,?is file 0 produc$ f page images at ,google ,books4 ,transcrib]'s ,note ,?is book 0 transcrib$ f a scan ( ! orig9al f\nd at ,google ,books4 ,i h rotat$ "s images4 ,"s ( ! m elaborate tables are treat$ z images4 ,illu/ration3 ,curtiss ,type ,,jn#d;,d ,biplane ,us$ by ,! ,unit$ ,/ates ,air ,mail ,s]vice 99,,a]oplane99 99,,con/ruction ,,&99 99,,op]ation99 ,includ+ ,notes ,on ,a]oplane ,design ,& ,a]odynamic ,calculation1 ,mat]ials1 ,etc4 ,a ,compreh5sive ,illu/rat$ ,manual ( ,in/ruction = ,a]oplane ,con/ructors1 ,aviators1 ,a]o-,me*anics1 ,flight ,(fic]s & ,/ud5ts4 ,adapt$ ,ei!r = ,s*ools or ,home ,/udy4 ,,by ,,john ,b4 ,,ra?bun ,,a]onautical ,,eng9e] ,consult+ ,a]onautical ,eng9e]1 ,*icago ,a]o ,works2 ,*ief ,eng9e]1 ,automotive ,eng9e]+ ,company4 ,=m]ly ,in/ructor 9 ,aviation & ,ma*9e ,design1 ,*icago ,te*nical ,college4 99,,*icago99 99,,/anton & ,,van ,,vliet ,,co499 99,,publi%]s99 #aiai ,copyright$1 #aiah ,by ,,/anton ,,& ,,van ,,vliet ,,co4 ,,a]oplane ,,con/ruction ,,& ,,op]ation ,,introduction ,_m a]onautical books ( a purely descriptive nature h be5 writt5 = ! av]age man1 b z a rule !y conta9 little ( int]e/ = ! m s]i\s /ud5t ( ! subject4 ,o!r books ( a highly te*nical & ma!matical class h also be5 publi%$1 b _! cont5ts are all b un9telligible to anyone b a tra9$ eng9e]4 ,x is ! purpose ( ! au?or to compromise betwe5 ^! two extremes1 & give only t "p ( ! !ory & description t w be ( practical use = ! build] & fly]4 ,! scope ( ! subjects cov]$ 9 ?is volume has be5 sugge/$ by ! que/ions ask$ by /ud5ts & cli5ts1 & is ! result ( _m ye>s' correspond5ce ) beg9n] aviators & amateur a]oplane build]s4 ,i h endeavor$ to expla9 ! pr9ciples ( ! a]oplane 9 simple1 concise language1 />t+ ) ! mo/ elem5t>y ideas ( flight & f9i%+ ) ! complete calculations = ! surfaces1 p[]1 weight1 etc4 ,:5 ma!matical op]ations are necess>y !y are simple 9 =m1 & are accompani$ by practical problems work$ out num]ically1 s t a man ) ev5 ! mo/ elem5t>y ma!matical k w h no difficulty 9 apply+ ! pr9ciple to 8 own "w4 ,9 cases :]e ! calculations w\ld necess>ily be complicat$1 ,i h sub/itut$ tables ( dim5sions = ! ma!matical op]ations1 ^! dim5sions be+ tak5 f a numb] ( repres5tative ma*9es4 ,:ile fly+ _c be taught by books1 & is only ! result ( actual exp]i5ce1 ! *apt] devot$ to ! use ( controls "u diff]5t flight conditions w be ( great b5efit to ! prospective aviator4 ,! portion ( ! book devot$ to op]ation w be ( use 9 fly+ s*ools & tra9+ camps s9ce bo? tra9+ me?ods & control manipulation are cov]$ 9 detail4 ,9 addition ,i h pres5t$ consid]able data on ! requirem5ts ( ! mod]n a]onautical motor4 ,s _m new firms are n[ ent]+ ! a]oplane indu/ry t !re is an ev] increas+ dem& = tra9$ me*anics1 design]s & fly]s1 & _m te*nical m5 n[ work+ along o!r l9es are tak+ a ke5 int]e/ 9 a]onautical eng9e]+4 ,if ! cont5ts ( ?is book w s]ve to inspire ! te*nical read] to deep] int]e/ & practical rese>* 9 ! fasc9at+ subject ( a]onautics1 ! au?or w be m ?an satisfi$ ) ! result ( 8 labor4 ,! a]oplane is rapidly assum+ a great comm]cial importance1 & !re is no d\bt b :at x w develop into an indu/ry rival+ t ( ! automobile4 ,to keep fully abrea/ ( ! times 9 a]onautic developm5t1 "o %\ld be a con/ant read] ( ! excell5t a]onautical magaz9es4 ,too mu* praise _c be giv5 to ! a]onautical press 9 its ef=t to ma9ta9 an int]e/ 9 ?is subject1 & z ) all pione]+ movem5ts1 ^! magaz9es h met ) _m disc\ragem5ts & f9ancial setbacks 9 ! e>li] days ( fly+4 ,to ! ,am]ican magaz9es1 ,a]ial ,age & ,fly+ 7,new ,york71 ! au?or owes a debt ( gratitude = ! use ( sev]al ( ! cuts appe>+ 9 ?is book4 ,! ,engli% magaz9es1 ,flight1 ,a]onautics & ! ,a]oplane1 h be5 simil>ly drawn on4 ,aviation & ,a]onautical ,eng9e]+ 7,new ,york7 has sugge/$ ! arrangem5t ( sev]al ( ! tables includ$ h]e94 ,all ( ^! pap]s are ( ! greate/ int]e/ & importance to ! eng9e]1 aviator & a]o-me*anic4 ,,john ,b4 ,,ra?bun4 ,,a]onautical ,,magaz9es ,! foll[+ li/ ( ,am]ican & ,engli% a]onautic publications w be ( int]e/ to ^? :o wi% to keep 9 t\* ) ! late/ developm5ts 9 a]onautics3 - ,,aviation ,,& ,,a]onautical ,,eng9e]+ 7two issues p] mon?74 ,a te*nical magaz9e publi%$ by ,! ,g>dn]-,m(fat ,co41 ,inc41 #abj ,w4 #cb;d ,/41 ,new ,york4 - ,,a]ial ,,age 7weekly74 ,popul> & te*nical4 ,! ,a]ial ,age ,co41 ,fo/] ,bldg41 ,madison ,ave4 & #dj? ,/41 ,new ,york4 - ,,air ,,s]vice ,,magaz9e 7weekly74 ,milit>y & popul> subjects4 ,g>dn]-,m(fat ,co41 ,inc41 #abj ,w4 #cb;d ,/41 ,new ,york4 - ,,fly+ 7mon?ly74 ,popul> & milit>y subjects4 ,publi%$ by ,fly+ ,association1 ,inc41 #bhj ,madison ,ave41 ,new ,york4 - ,,air ,,travel 7weekly74 ,popul> subjects4 ,publi%$ by ,air ,travel1 ,new ,york4 ,,engli% ,,magaz9es4 - ,,flight ,,& ,,! ,,aircraft ,,eng9e] 7weekly74 ,te*nical & popul>4 ,publi%$ by ,flight & ,aircraft ,eng9e]1 #cf ,great ,que5 ,/41 ,k+sway1 ,w4,c4#b1 ,london1 ,engl&4 - ,,a]onautics 7weekly74 ,te*nical & indu/rial4 ,publi%$ by ,a]onautics1 #f-h ,b\v]ie ,/41 ,london1 ,e4,c4#d1 or may be _h f #agij ,broadway1 ,new ,york4 - ,,! ,,a]oplane 7weekly74 ,te*nical & popul>4 ,publi%$ by ,! ,a]oplane1 #aff ,piccadilly1 ,london1 ,w4#a4 ,,a]oplane ,,con/ruction ,,& ,,op]ation 444444444444444444444444444444 ,,introduction 4444444444444444444444444444444444444444 444444444444 ,,a]onautical ,,magaz9es 4444444444444444444444444444444444444444 44 ,,engli% ,,magaz9es4 4444444444444444444444444444444444444444 444444 ,,*apt] ,i4 ,,pr9ciples ,,( ,,! ,,a]oplane4 4444444444444444444444444 ,,*apt] ,,ii4 ,,types ,,( ,,milit>y ,,a]oplanes4 44444444444444444444444 ,,*apt] ,,iii4 ,,elem5t>y ,,a]odynamics 4444444444444444444444444444 ,,*apt] ,,iv4 ,,exp]im5tal ,,laboratories4 44444444444444444444444444 ,,*apt] ,v4 ,,a]odynamics ,,( ,,lift+ ,,surfaces 7,,a](oils74 44444444 ,,*apt] ,,vi4 ,,practical ,,w+ ,,sections4 4444444444444444444444444444 ,,correction ,,factors ,,= ,,w+ ,,=m ,,& ,,size4 44444444444444444444 ,,*apt] ,,vii4 ,,biplanes ,,& ,,triplanes4 4444444444444444444444444444 ,,*apt] ,,viii4 ,,effects ,,( ,,plan ,,=m4 7,,t&em ,,a]oplanes47 44444444 ,,*apt] ,,ix4 ,,w+ ,,con/ruction4 4444444444444444444444444444444444 ,,*apt] ,x4 ,,w+ ,,con/ruction ,,details4 444444444444444444444444444 ,,*apt] ,,xi ,,fuselage 7,,body7 ,,con/ruction4 444444444444444444444444 ,,*apt] ,,xii ,,details ,,( ,,fuselage ,,con/ruction 44444444444444444444 ,,fuselage ,,weights4 4444444444444444444444444444444444444444 44444 ,,size ,,( ,,long]ons 4444444444444444444444444444444444444444 44444 ,,*apt] ,,xiii4 ,,*assis ,,con/ruction4 44444444444444444444444444444 ,,*apt] ,,xiv4 ,,e/imation ,,( ,,weight4 444444444444444444444444444444 ,,weights ,,( ,,a]onautical ,,motors4 4444444444444444444444444444444 ,,*apt] ,,xv4 ,,balance ,,& ,,/ability4 444444444444444444444444444444 ,,*apt] ,,xvi4 ,,head ,,resi/ance ,,calculations4 4444444444444444444444 ,,*apt] ,,xvii4 ,,p[] ,,calculations4 4444444444444444444444444444444 ,,*apt] ,,xviii4 ,,propell]s4 44444444444444444444444444444444444444 ,,*apt] ,,xix4 ,,op]ation ,,& ,,tra9+4 4444444444444444444444444444 ,,*apt] ,,xx4 ,,a]onautical ,,motors4 44444444444444444444444444444444 ,,*apt] ,,xxi4 ,,gloss>y ,,( ,,a]onautical ,,words4 44444444444444444444 ,a 4444444444444444444444444444444444444444 444444444444444444444 ,b 4444444444444444444444444444444444444444 444444444444444444444 ,c 4444444444444444444444444444444444444444 444444444444444444444 ,d 4444444444444444444444444444444444444444 444444444444444444444 ,e 4444444444444444444444444444444444444444 444444444444444444444 ,f 4444444444444444444444444444444444444444 444444444444444444444 ,g 4444444444444444444444444444444444444444 444444444444444444444 ,h 4444444444444444444444444444444444444444 444444444444444444444 ,i 4444444444444444444444444444444444444444 444444444444444444444 ,j 4444444444444444444444444444444444444444 444444444444444444444 ,k 4444444444444444444444444444444444444444 444444444444444444444 ,l 4444444444444444444444444444444444444444 444444444444444444444 ,m 4444444444444444444444444444444444444444 444444444444444444444 ,n 4444444444444444444444444444444444444444 444444444444444444444 ,o 4444444444444444444444444444444444444444 444444444444444444444 ,p 4444444444444444444444444444444444444444 444444444444444444444 ,p 4444444444444444444444444444444444444444 444444444444444444444 ,s 4444444444444444444444444444444444444444 444444444444444444444 ,t 4444444444444444444444444444444444444444 444444444444444444444 ,u 4444444444444444444444444444444444444444 444444444444444444444 ,v 4444444444444444444444444444444444444444 444444444444444444444 ,w 4444444444444444444444444444444444444444 444444444444444444444 ,,*apt] ,i4 ,,pr9ciples ,,( ,,! ,,a]oplane4 99,me*anical ,flight994 ,al?\gh ! elem5t>y pr9ciples ( me*anical flight are n ( rec5t orig91 ! practical developm5t ( ! fly+ ma*9e is conf9$ almo/ entirely to ! pres5t c5tury4 ,gravity propell$ glid]s & small models h be5 fl[n ) success f a comp>atively e>ly date1 b ! fir/ actual su/a9$ flight ) a p[] driv5 ma*9e 0 p]=m$ by ! ,wright ,bro!rs 9 #aijc4 ,!re 0 no s+le elem5t on ?is fir/ successful ma*9e t _h n be5 propos$ _m ye>s be=e by ,langley1 ,*anute1 ,montgom]y1 ,h5son1 ,m\ill>d1 & o!rs1 b ?is fir/ flight mu/ be attribut$ pr9cipally to ! fact t ! ,wrights />t$ c>efully & pa9/ak+ly to le>n h[ to op]ate 7,by practic+ ) glid]s7 be=e />t+ on ! fir/ p[] ma*9e4 ,if ,langley _h /udi$ ! op]ation ( 8 ma*9e z c>efully z he did its !ory & design1 he w\ld h be5 fly+ long be=e ! ,wrights z 8 orig9al ma*9e 0 aft]w>ds successfully fl[n by ,curtiss4 ,:5 once actual flight 0 a*iev$1 & ! success ( ! ,wright ,bro!rs became g5]ally kn[n1 ! developm5t proce$$ ) leaps & b\nds4 ,all ! res\rces ( sci5ce & eng9e]+ skill 7 at once appli$ to ! new device until our pres5t sci5tific k ( ! a]oplane comp>es v favorably ) ! old] eng9e]+ sci5ces4 ,9 ! few ye>s t h elaps$ s9ce ! fir/ flight1 ! a]oplane holds all records = spe$1 endurance1 & radius ( action4 ,a great deal ( ! success s rapidly acquir$ c be cr$it$ to ! automobile & motorcycle indu/ries1 s9ce x 0 ! developm5t ( ! light int]nal combu/ion motors us$ on ^! ma*9es t pav$ ! way = ! /ill light] a]onautic motor4 ,aga91 ! automobile indu/ry 0 responsible = ! light & p[]ful mat]ials ( con/ruction1 su* z alloy /eel1 alum9um alloys1 & also = ! highly important con/ructional details1 su* z ball be>+s1 pneumatic tires1 c>buretors1 magnetos1 /eel tub+1 etc4 ,! special me?ods develop$ 9 automobile "w h help$ to make ! a]oplane an imm$iate comm]cial proposition4 ,illu/ration3 ,curtiss ,type ,,jn#d-;,b ,prim>y ,tra9] 99,types ( ,fly+ ,ma*9es994 ,9 g5]al1 flight app>atus may be divid$ into two classes1 7#a7 ,! ,light] ,?an ,air ,type1 su* z ! balloon & dirigible1 & 7#b7 ,! ,heavi] ,?an ,air ,ma*9e1 repres5t$ by ! a]oplane1 helicopt] & orni?opt]4 ,! light] ?an air ma*9e is support$ 9 flight by buoyancy 9 mu* ! same mann] t a piece ( wood floats 9 wat]4 ,:5 a balloon or dirigible1 because ( its l>ge volume1 displaces a volume ( air equal to its own weight1 ! device w float4 ,:5 ! weight ( air displac$ exce$s ! weight ( ! balloon or dirigible1 x w cont9ue to rise until x rea*es an altitude :]e ! dim9i%$ air d5sity aga9 results 9 an equality betwe5 ! weight ( ! device & ! air displac$4 ,at ?is po9t x re/s1 or is 9 equilibrium4 ,! flotation ( su* a device is entirely due to /atic =ces & h5ce 7#a7 is (t5 call$ an a]o/at4 ,! su/5ation ( a ,heavi] ,?an ,air ,ma*9e is due to an entirely diff]5t application ( =ces4 ,=ces 9 motion 7,dynamic ,=ces7 are ess5tial to ! support ( a heavi] ?an air ma*9e1 & x is ! resultant ( ^! =ces t p]=ms ! actual lift+ op]ation1 ?is resultant correspond+ to ! buoyant =ce ( ! a]o/at4 ,dynamic flight is obta9$ by an app>atus 9 :i* an arrangem5t ( surfaces are mov$ 9 su* a way z to cause an upw>d compon5t ( ! =ces g5]at$ by ! impact ( ! air on ! surfaces4 ,! surfaces drive ! air d[n & :5 ! =ce necess>y = ! cont9u\s d[nw>d deflection ( air becomes equal to ! weight ( ! ma*9e x is su/a9$ 9 flight4 ,dynamic flight !re=e dep5ds on ! cont9u\s d[nw>d deflection ( masses ( air1 & :5 ?is motion ceases1 su/5tation also ceases4 ,an a]oplane is provid$ ) a deflect+ surface t is fix$ rigidly 9 reg>d to ! body ( ! ma*9e1 & ! motion necess>y = its support is provid$ by driv+ ! ma*9e =w>d1 ! =w>d motion be+ produc$ by ! horizontal pull ( air screws or propell]s4 ,x is at once evid5t t ! =w>d horizontal motion ( ! a]oplane mu/ be ma9ta9$ = its support1 = ! surfaces are fix$ & !re is no o!r possible way ( produc+ a relative motion betwe5 ! w+s & ! air4 ,to ov]come ! objection ( =w>d motion1 sev]al o!r ma*9es h be5 propos$ 9 :i* ! surfaces are mov$ 9 relation to ! body1 z well z ! air1 ?us mak+ x possible = ! device to /& /ation>y :ile ! revolv+ or reciprocat+ surfaces /ill cont9ue 9 motion 9 reg>d to ! air4 ,"o type ( ! mov+ surface ma*9e1 ! ,helicopt]1 is provid$ ) revolv+ surfaces arrang$ 9 ! =m ( v]tical air screws or propell]s1 ! blades ( ! propell]s be+ incl9$ s t !y drive d[n a cont9u\s /ream ( air & produce ! cont9u\s upw>d reaction t supports ! ma*9e4 ,:ile su* ma*9es h succe$$ 9 rais+ !mselves (f ! gr\nd !y are n yet practical fly+ devices4 ,! orni?opt] or or?opt] is a flapp+ w+ ma*9e t ma9ta9s flight aft] ! mann] ( ! bird 7,ornis74 ,l ! helicopt]1 ! orni?opt] has n yet prov$ successful4 ,illu/ration3 ,fig4 #a4 ,comp>ison ,betwe5 ! ,kite & ,a]oplane2 ,fig4 #b1 ,%[+ ! ,lift & ,drag ,=ces ,produc$ by ! ,air ,/ream4 ,! ,propell] 7,p71 ,acts 9 a ,mann] ,simil> to ! ,kite ,/r+ 7,s7 9 ,produc+ ,relative ,motion ,betwe5 ! ,air & ! ,lift+ ,surfaces4 99,pr9ciples ( ! ,a]oplane994 ,9 its elem5t>y pr9ciples1 ! a]oplane c be comp>$ ) ! kite1 z bo? are support$ by ! impact ( a horizontal /ream ( air4 ,9 ,diagram #a1 ! kite surface is indicat$ by ,x-,x ) ! relative air /ream ,w-,w-,w-,w mov+ f left to ! "r z indicat$ by ! arr[ heads4 ,on /rik+ ! surface1 ! air /ream is deflect$ v]tically1 & 9 a d[nw>d direction1 z %[n by ! /reams l9es ,r-,r-,r-,r4 ,! reaction ( ! air deflection produces ! lift %[n v]tically & upw>ds by ! arr[ ,l4 ,! kite surface is held aga9/ ! impact ( ! air /ream by ! /r+ ,s s t !re is relative motion betwe5 ! air & ! kite1 & s t ! surface w n be c>ri$ along ) ! air curr5t t[>d ! "r4 ,if ! kite 7 all[$ to drift ) ! w9d !re c\ld be no relative motion betwe5 ! surface & ! air /ream1 h5ce ! kite w\ld fall z soon z x atta9$ ! velocity ( ! w9d4 ,! horizontal =ce ex]t$ by ! w9d t5d+ to c>ry ! kite t[>d ! "r is indicat$ by ! arr[ ,d & is kn[n z ! drag or drift =ce4 ,!re are ?us ?ree =ces1 ! lift 7,l71 ! drag 7,d71 & ! resultant ( ! two =ces indicat$ by ! /r+ 7,s74 ,! =ces ( lift & drag are ne>ly at "r angles to "o ano!r4 ,! kite tail ,t is simply a /abiliz+ device ^: purpose is to ma9ta9 a con/ant angle betwe5 ! surface & ! w9d & x p]=ms an almo/ negligible am\nt ( lift4 ,a few m words 9 reg>d to ! relative velocity betwe5 ! surface & w9d4 ,9 ! figure1 ! kite is assum$ z be+ /ation>y1 :ile ! w9d moves f left to "r4 ,) a ?irty mile p] h\r w9d1 ! relative air velocity 9 reg>d to ! surface w\ld be #cj ,m4 ,p4 ,h4 ,if ! air p>ticles are n[ consid]$ /ation>y1 & if ! kite is t[$ t[>d ! left 7opposite to figure7 at #cj miles p] h\r1 ! relative velocity betwe5 ! surface & air w\ld /ill be #cj ,m4 ,p4 ,h4 ,9 o!r words1 ! kite may be /ation>y1 or may move 9 reg>d to ! e>?1 b its lift is unaffect$ z long z ! relative motion betwe5 ! surface & air rema9s con/ant4 ,! motion betwe5 an a]oplane & ! e>? dep5ds ^u ! diff]5ce ( ! a]oplane & w9d velocities4 ,= example1 a a]oplane ) a relative spe$ ( #fj miles p] h\r1 fly+ aga9/ a headw9d ( #cj miles p] h\r1 moves #fj-cj #cj miles p] h\r 9 reg>d to ! e>?4 ,! same a]oplane fly+ ) ! above w9d w\ld h a velocity ( #fjcjij miles p] h\r pa/ a fix$ po9t on ! e>?'s surface1 yet 9 bo? cases1 ! relative velocity ( ! surface 9 reg>d to ! air w\ld be ! same4 ,fig4 #b is a diagram ( an a]oplane t %[s ! connection betwe5 ! kite & a]oplane pr9ciples4 ,9 ?is figure1 ! w+ surface ( ! a]oplane1 ,x-,x corresponds to ! kite surface ,x-,x4 ,! relative air ,w-,,ww-,w /rik+ ! w+ f ! left is deflect$ d[n along ! arr[s ,r-,r-,r-,r & results 9 an equival5t lift =ce ,l1 & a drag =ce ,d z 9 ! case ( ! kite4 ,! resultant =ce requir$ to ma9ta9 ! relative velocity betwe5 ! air & w+s is indicat$ by ,d1 opposite & equal to ! drag =ce ,d4 ,! resultant requir$ = ov]com+ ! drag is provid$ by ! screw propell] ,p in/ead ( ! /r+ ,s %[n 9 ,fig4 #a4 ,! propell] ?ru/ 7,d7 is p>allel to ! air /ream in/ead ( be+ incl9$ z 9 ! case ( ! /r+1 b ! total effect is ! same s9ce bo? are ,resultants ( ! lift & drag4 ,to su/a9 ! a]oplane1 ! lift 7,l7 mu/ be equal & opposite to ! weight %[n by ,m4 ,! fact t ,m & ,l are opposite & equal makes x only necess>y = ! propell] to ov]come ! horizontal drag1 & h5ce ! ?ru/ c be made p>allel to ! air fl[--or ne>ly s4 ,! a]oplane is provid$ ) a small tail surface 7,t7 t corresponds to ! kite tail 7,t74 ,x ma9ta9s ! lift+ surfaces ,x-,x at a giv5 angle ) ! air /ream4 ,! tail may1 or may n aid 9 support+ ! ma*9e1 b 9 mod]n ma*9es x is common to employ a tail surface t is non-lift+ "u ord9>y conditions ( normal flight4 ,! body 7,b7 conta9s ! pilot1 motive p[]1 fuel1 & su* useful load z x may be necess>y to c>ry4 ,illu/ration3 ,fig4 #c4 ,caudron ,monoplane4 ,side ,elevation4 ,fig4 #c %[s a ,caudron monoplane 9 side elevation4 ,?is view illu/rates ! application ( ! pr9ciples %[n by ,fig4 #b1 except = ! v]tical rudd] at ! re>4 ,! latt] is us$ = /e]+ 9 a horizontal direction4 ,fig4 #d %[s ! con/ruction ev5 m cle>ly s9ce x is a p]spective view4 ,! ma*9e is a ,morane ,p>asol monoplane ) ! w+ plac$ ov] ! body4 ,?is location ( ! ma9 lift+ surface is = ! purpose ( improv+ ! view ( ! pilot & 9 no way affects ! pr9ciples j describ$4 ,! wires %[n above ! w+ are brac+ /ays4 ,! tail is h+$ ne> ! re> s t ! angle ( ! re> portion c be *ang$ 7,elevator flaps71 & p]mits ! angle ( ! ma9 w+s to be alt]$ 9 reg>d to ! air /ream1 ?us caus+ ! ma*9e to asc5d or desc5d4 ,! tail also damps out oscillations or vibrations due to irregul>ities 9 ! air curr5t4 ,! :eels & runn+ ge> 7,*assis7 all[ ! ma*9e to be run ov] ! gr\nd until ! relative air spe$ is suffici5t to support ! ma*9e 9 flight4 ,illu/ration3 ,fig4 #d4 ,morane ,umbrella ,type ,monoplane4 ,c\rtesy ( ,flight4 99,multiplanes994 ,9 ord] to support a heavy load1 & at ! same "t h a small compact ma*9e1 x is necess>y to h m ?an "o lay] ( w+ surface4 ,x is evid5t t ! w+ l5g? or span c be made mu* less ?an t ( ! monoplane surface %[n1 if ! total area c\ld be divid$ into two or m p>ts4 ,a ma*9e hav+ its ma9 lift+ surface divid$ into two or m sep>ate sections is kn[n z a multiplane1 ?is t]m becom+ ,biplane1 ,triplane1 or ,quadraplane1 dep5d+ on :e!r !re are two1 ?ree or f\r indep5d5t lift+ surfaces4 ,!re is almo/ a limitless v>iety ( arrangem5ts possible1 b ! mo/ common arrangem5t by f> is t ( ! biplane1 9 :i* !re are two sup]pos$ surfaces z %[n by ,fig4 #e4 ,9 ?is type1 ! two lift+ surfaces are plac$ ov] "o ano!r ) a consid]able gap or space betwe54 ,! body is plac$ betwe5 ! w+s & ! tail surfaces & *assis rema9 ! same z 9 ! monoplane4 ,?is is kn[n z a ,tractor biplane s9ce ! propell] is 9 front & pulls ! ma*9e along :ile ,fig4#f %[s a ,pu%] type biplane 9 :i* ! propell] is m\nt$ beh9d ! w+s & !re=e pu%es ! ma*9e4 ,illu/ration3 ,fig4 #d-;,a4 ,dep]duss9 ,monoplane ) ,monocoque ,body4 ,gordon-,b5nett ,rac]4 99,biplanes994 ,besides ! advantages ( size1 ! biplane has a numb] ( o!r good features4 ,! deep spac+ ( ! upp] & l[] surfaces p]mits ( a p[]ful & light sy/em ( truss+ be+ plac$ 9 ! gap1 & !re=e ! biplane c be made /rong] 7weight = weight7 ?an ! monoplane 9 :i* no su* truss+ c be economically appli$4 ,! v]tical /ruts ( ! brac+ c be cle>ly se5 9 ! figure4 ,! effici5cy ( ?is int]plane truss+ greatly increases ! possible size & capacity ( ! a]oplane4 ,) monoplanes x is seldom possible to exce$ a w+ span ( #cf feet )\t runn+ into almo/ unsurm\ntable /ructural difficulties4 ,! weight ( ! l>ge monoplane also increases is leaps & b\nds :5 ?is critical span is once exce$$4 ,to ma9ta9 an equal degree ( /r5g? ! monoplane requires v c>eful att5tion 9 reg>d to ! design & con/ruction1 & is correspond+ly m exp5sive & difficult to build ?an ! biplane1 al?\gh ! latt] has by f> ! great] numb] ( p>ts4 ,by suitable arrangem5ts 9 ! location ( ! biplane surfaces a v fair degree ( /ability c be obta9$1 an advantage :i* is impossible ) ! monoplane4 ,illu/ration3 ,fig4 #e4 ,s4 ,p4 ,a4 ,d4 ,tractor ,biplane ,spe$ ,sc\t4 ,a di/9ct disadvantage ( ! two sup]pos$ surfaces ( ! biplane is due to ! fact t !re is int]f]5ce betwe5 ! upp] & l[] w+s1 & t ! lift = equal areas is less ?an 9 ! case ( ! monoplane4 ,) a giv5 =m ( w+1 #ajj squ>e feet ( monoplane surface w lift consid]ably m ?an ! same area appli$ 9 biplane =m4 ,! am\nt ( ! drag = ! support ( a giv5 load is increas$1 & ) x ! am\nt ( p[] requir$4 ,! great] ! sep>ation or gap betwe5 ! w+s1 ! great] w be ! lift1 b :5 ! gap is unduly increas$ to obta9 a great lift ! l5g? ( ! int]plane brac+ is increas$ to su* an ext5t t ! resi/ance ( ! brac+ w m ?an ov]come ! advantages due to ! l>ge gap4 ,!re is a fix$ limit to ! gap beyond :i* x is n practical to g4 ,! brac+ has a v mat]ial effect on ! air resi/ance1 no matt] h[ small ! gap4 ,illu/ration3 ,fig4 #f4 ,pu%] ,type ,biplane 9 ,:i* ! ,propell] ,is ,plac$ ,beh9d ! ,w+s4 99,triplanes994 ,( late ! triplane has be5 rapidly increas+ 9 use1 & 9 c]ta9 respects has _m advantages ov] ei!r ! monoplane or biplane4 ,?is type has ?ree sup]pos$ surfaces :i* /ill fur!r dim9i%es ! size = a giv5 area4 ,! int]f]5ce betwe5 ! surfaces is ev5 great] ?an ) ! biplane1 & h5ce ! lift is less = a giv5 area & aspect ratio4 ,?is latt] defect is p>tly1 or :olly ov]come by ! possibility ( us+ long n>r[ w+s1 & because ( ! r$uc$ span !re is a correspond+ r$uction 9 ! brac+ resi/ance4 ,x %\ld be not$ at ?is po9t t ! effici5cy ( a lift+ surface is greatly increas$ :5 ! ratio ( ! l5g? to ! wid? is increas$1 t is1 a long1 n>r[ w+ w be m effici5t ?an a %ort1 wide %ape4 ,! relation ( ! l5g? to ! wid? is call$ aspect ratio1 & w be describ$ 9 m detail 9 a foll[+ *apt]4 ,illu/ration3 ,fig4 #f-;,a4 ,f>man ,type ,pu%] ,biplane4444 ,note ! ,propell] ,at ! ,re> ( ,body1 & ! ,position ( ! ,pilot & ,pass5g]4 ,illu/ration3 ,fig4 #f-;,b4 ,! ,mann ,two-,propell] ,pu%] ,biplane4 ,! ,propell]s ,are ,m\nt$ on ,ei!r ,side ( ! ,body1 & ,are ,driv5 by a ,s+le ,motor ,?r\gh a ,*a9 ,transmission4 ,?is ,drive ,is ,simil> to ! ,e>ly ,wright ,ma*9es4 ,fig4 #g is a sket* ( a ,sop) ,triplane ,sc\t & %[s cle>ly ! ?ree sup]pos$ w+s4 ,! small am\nt ( int]plane brac+1 & ! great aspect ratio1 makes ?is type v suitable = high spe$4 ,! body1 tail & *assis arrangem5ts are practically ! same z ^? ( a biplane4 ,! ,curtiss ,triplane ,sc\t is ! pione] ( ?is type ( ma*9e1 al?\gh exp]im5tal "w on ! triplane _h be5 p]=m$ 9 ,engl& by ,a4 ,v4 ,roe _m ye>s ago4 ,! ,roe triplane 0 lightly p[]$ & = its "t 0 successful 9 a way1 b ! ,curtiss is ! fir/ to ent] into active competition aga9/ ! biplane sc\t4 ,ow+ to ! small span requir$ = a giv5 area1 & ! possibilities ( v light & simple brac+1 ! triplane is an ideal type = heavy duty ma*9es ( ! bomb+ species4 ,enorm\s triplanes h be5 made t are capable ( a useful load runn+ up into ! tons1 ! l>ge ,curtiss & ,caproni's be+ notable examples4 ,z ! triplane is mu* high] ?an ! biplane ( equal area1 ! int]plane brac+ is deep] & m effective )\t caus+ proportionately high] resi/ance4 ,illu/ration3 ,fig4 #g4 ,sop) ,triplane ,spe$ ,sc\t4 99,quadraplane994 ,! use ( f\r sup]pos$ surfaces has n be5 ext5d$1 !re probably be+ only "o or two ( ^! ma*9es t c be said to be successful4 ,! small quad built by ,mat!w ,b4 ,sell]s is probably ! be/ kn[n4 ,! p[] requir$ to ma9ta9 ?is ma*9e 9 flight 0 surpris+ly small1 ! ma*9e gett+ (f ! gr\nd ) a #d horsep[] motor1 al?\gh an #h horsep[] 0 aft]w>ds in/all$ to ma9ta9 cont9u\s flight4 ,! empty weight 0 #aaj p\nds ) ! #h horsep[] motor4 ,! span ( ! w+s 0 #ah' #j & ! wid? or *ord #c' #j1 giv+ a total area ( ab\t #bjj squ>e feet4 ,illu/ration3 ,fig4 #g-;,a4 ,curtiss ,triplane ,spe$ ,sc\t4 ,c\rtesy ,a]ial ,age4 99,t&em ,a]oplanes994 ,a t&em a]oplane may be describ$ z be+ "o 9 :i* ! surfaces are arrang$ =e & aft4 ,! ,langley ,a]odrome 0 ( ! t&em monoplane type & consi/$ ( two sets ( monoplane w+s arrang$ 9 t&em4 ,?is pione] ma*9e is %[n 9 ,fig4 #h1 & is ! fir/ p[] driv5 model to a*ieve a cont9u\s flight ( any l5g?4 ,in/ead ( two monoplane surfaces1 two biplane units or triplane units c be arrang$ =e & aft 9 ! same mann]4 ,:ile !re h be5 a numb] ( t&em ma*9es built1 !y h n come into ext5sive use4 ,successful flight 0 obta9$ ) a full size ,langley ,a]odrome1 & ?is ma*9e flew ) a fair degree ( /ability4 ,! failure ( o!r t&em ma*9es to make good 0 due1 9 ! writ]'s op9ion1 to poor con/ruction & design r ?an to a failure ( ! t&em pr9ciple4 ,! ,montgom]y glid]1 fam$ = its /ability1 0 a t&em type b ! ma*9e 0 nev] successfully built z a p[]$ ma*9e4 ,! w+s mu/ be sep>at$ by a suffici5t di/ance s t ! re> set w n be greatly influ5c$ by ! d[nw>d tr5d ( ! air caus$ by ! lead+ w+s4 ,z ! re> surfaces always "w on di/urb$ air !y %\ld be *ang$ 9 angle1 increas$ 9 area1 or be equipp$ ) a diff]5t w+ curvature if !y are to c>ry an equal proportion ( ! load4 ,usually1 h[ev]1 ! areas ( ! front & re> w+s are equal1 & ! diff]5ce 9 lift is made by *anges 9 ! w+ =m or angle at :i* !y are set4 ,9 "s cases ! w+s are approximately ! same1 ! diff]5ce 9 lift be+ comp5sat$ = by mov+ ! load fur!r =w>d1 ?us ?r[+ m ( ! weight on ! front w+s4 ,illu/ration3 ,fig4 #h4 ,langley's ,a]odrome1 ,an ,e>ly ,type ( ,t&em ,monoplane4 99,! ,a]oplane 9 ,flight994 ,up to ! pres5t we h only consid]$ horizontal flight at a cont9u\s spe$4 ,9 actual flight ! altitude is frequ5tly v>i$ & ! spe$ is *ang$ to meet diff]5t conditions4 ,aga91 ! load is n an absolutely con/ant quantity ow+ to v>iations 9 ! weight ( pass5g]s1 & v>iations 9 ! weight ( fuel1 ! weight ( ! latt] dim9i%+ directly ) ! l5g? ( ! "t ( flight4 ,to meet ^! v>iations1 ! lift ( ! w+s mu/ be alt]$ to suit ! load+ & spe$--g5]ally by alt]+ ! angle ( ! w+s made ) ! l9e ( flight4 ,fig4#i %[s an a]oplane 9 horizontal flight & lightly load$1 ! ma*9e travel+ along ! horizontal flight pa? ,f-,f4 ,) ! light load1 ! angle made by ! w+s ) ! flight pa? is %[n by 7i71 ! tail & body rema9+ horizontal1 or p>allel to ! flight pa?4 ,) an increas$ load x is necess>y to increase ! angle ( ! w+s ) ! flight l9e1 s9ce )9 c]ta9 limits ! lift increases ) an increase 9 ! angle ( incid5ce 7i74 ,fig4 #aj %[s ! adju/m5t = a heavi] load 7,w71 ! angle ( incid5ce be+ increas$ to 7i'71 & ! body is turn$ d[n ?r\gh a correspond+ angle4 ,! increas$ angle is obta9$ by turn+ ! elevator flaps 7,t7 up1 ?us caus+ a d[nw>d =ce 7t7 on ! tail4 ,! =ce 7t7 acts ?r\gh ! body z a lev] arm1 & turns ! ma*9e into its new position4 ,x w be not$ t :5 ! angle ( incid5ce is great t ! re> ( ! body drags d[n & causes a heavy resi/ance4 ,?is position ( a dragg+ tail is kn[n to ! ,fr5* z fly+ ,cabr4 ,) high angles cabr flight is dang]\s1 = %\ld ! propell] ?ru/ cease = an in/ant ! ma*9e w\ld be likely to tail dive be=e ! pilot c\ld rega9 control4 ,?is sort ( flight is also wa/eful ( p[]4 ,cabr flight is unnecess>y 9 a v>iable incid5ce ma*9e1 ! w+ be+ turn$ to ! requir$ angle indep5d5tly ( ! body1 s t ! body foll[s ! flight l9e 9 a horizontal position1 no matt] :at ! angle ( incid5ce may be4 ,9 ?is type ( ma*9e ! w+s are pivot$ to ! body1 & are op]at$ by "s =m ( manual control4 ,illu/ration3 ,figs4 #i-aj-aa-ab4 ,%[+ ! ,use ( ,elevators 9 ,*ang+ ,angle ( ,incid5ce4 - ,ma*9e ,%[n 9 ,f\r ,pr9cipal ,attitudes ( ,flight4 ,z ! ,body & ,w+s ,are 9 a ,s+le ,unit1 ! ,body ,mu/ ,be ,turn$ = ,ea* ,diff]5t ,w+ ,angle4 ,9 ,fig4 #aa1 ! l>ge angle 7i'7 is /ill ma9ta9$1 b ! load is r$uc$ to ! value giv5 9 ,fig4 #i4 ,) an equal load1 an increas$ angle ( incid5ce causes ! ma*9e to climb1 z along ! new flight l9e f-f4 ,) ! load 7,w7 equal to t 9 ,fig4 #i1 ! angle ( incid5ce w /ill be 7i7 b ?is w be along a new flight l9e if ! l>ge angle 7i'7 is ma9ta9$ ) ! horizontal z %[n by ,fig4 #aa4 ,) ! w+s mak+ an angle ( 7i'7 ) ! horizontal1 & angle ( incid5ce 7i7 ) ! flight l9e1 x is evid5t f ,fig4 #aa t ! new flight l9e f-f mu/ make an angle 7c7 ) ! orig9al horizontal flight l9e ,f-,f4 ,?is %[s h[ an increas$ angle ) a con/ant load causes climb+1 provid+1 ( c\rse1 t ! spe$ & p[] are ma9ta9$4 ,) a giv5 w+ & load !re is a def9ite angle ( incid5ce if ! spe$ is kept con/ant4 ,%\ld a load be dropp$1 su* z a bomb1 ) ! w+ angle kept con/ant1 ! new pa? ( travel w be *ang$ f ,f-,f to f-f4 ,fig4 #ab %[s ! condition :5 ! re> end ( ! body is elevat$ by depress+ ! elevator flap ,t4 ,?is occasions an upw>d tail =ce t turns ! w+s d[n ?r\gh ! total angle 7i'74 ,) ! =m] load+ & spe$1 ! angle ( incid5ce is /ill 7i7 degrees ) ! new flight pa? f-f1 ! new flight pa? be+ at an angle 7c7 ) ! horizontal ,f-,f4 ,! body is turn$ ?r\gh angle 7i'71 b ! angle 7i7 ) ! flight pa? f-f is /ill con/ant ) equal loads & spe$s4 ,to cause an a]oplane to climb1 or to c>ry a heavi] load1 ! elevator flap is po9t$ up4 ,to desc5d1 or c>e = a light] load1 ! elevator is turn$ d[n4 ,9 normal horizontal flight ! ma*9e %\ld be balanc$ s t ! tail is horizontal & ?us creates no drag4 ,:5 ! elevator 99mu/99 be us$ to keep ! tail up 9 horizontal flight1 ! ma*9e is said to be tail heavy4 99,longitud9al ,/ability994 ,9 ,figs4 #i-aj-aa-ab ! ma*9e 0 assum$ to be fly+ 9 /ill air1 ! attitudes ( ! ma*9e be+ simply due to *anges 9 ! load+ or to a *ange 9 altitude4 ,! actual case is m complicat$ ?an ?is1 = ! reason t ! ma*9e is nev] op]at+ 9 /ill air b enc\nt]s sudd5 gu/s1 :orls1 & o!r erratic v>iations 9 ! d5sity & velocity ( ! air4 ,ea* v>iation 9 ! surr\nd+ air causes a *ange 9 ! lift ( ! w+s1 or 9 ! effect ( ! tail surfaces1 & h5ce t5ds to upset ! ma*9e4 ,if su* w9d gu/s w\ld always /rike ! w+s1 body1 & tail simultane\sly1 !re w\ld be no tr\ble1 b1 un=tunately1 ! air gu/ /rikes "o portion ( ! ma*9e & an appreciable l5g? ( "t elapses be=e x travels f> en\gh to /rike ano!r4 ,?\gh ?is may seem to be a small fraction ( "t1 x is 9 reality ( suffici5t duration to h a mat]ial effect on ! poise ( ! a]oplane4 ,v]tical gu/s due to ! w9d pass+ ov] build+s1 hills1 cliffs1 etc41 n only t5d to upset ! ma*9e1 b also t5d to *ange ! altitude s9ce ! ma*9e rises ) an up gu/ & s9ks ) a d[n tr5d 9 ! ,/ream4 ,assume a ma*9e z 9 ,fig4 #i to be travel+ /eadily along a horizontal pa? 9 /ill air4 ,a sudd5 horizontal gu/ n[ /rikes ! ma*9e f ! front1 ?us caus+ a sudd5 lift 9 ! ma9 w+s4 ,z ?is gu/ /rikes ! w+s be=e ! tail1 ! tail w /& at ! old altitude :ile ! w+s are lift$1 ?us giv+ ! position %[n by ,fig4 #aj4 ,aft] pass+ ov] ! w+s x lifts ! tail1 ?is effect probably n be+ suffici5t to re/ore ! w+ & ! tail to _! old relative attitude s9ce ! gu/ g5]ally loses velocity aft] pass+ ! w+s4 ,a head gu/ ( ?is type (t5 /rikes ! front w+s diagonally s t x nev] rea*es ! tail at all4 ,to rem$y ?is upsett+ action ( ! gu/1 ! pilot mu/ move 8 re> elevator s t ! elevator is 9 ! position %[n by ,fig4 #ab1 t is1 ! flap mu/ be turn$ d[n s z to raise ! tail4 ,a gu/ /rik+ f beh9d may1 or may n affect ! elevator flaps1 ?is dep5d+ on _! position at ! "t t ! gu/ /rikes4 ,if ! flaps are turn$ up1 ! re> end w be rais$ by ! gu/ & ! ma*9e w head dive3 if turn$ d[n1 ! gu/ w depress ! tail1 raise ! head & t5d to /all ! ma*9e4 ,if ! tail is ( ! lift+ type1 ! re> ent]+ gu/ w r$uce ! relative velocity1 & ! lift1 & cause ! tail to drop4 ,on pass+ ov] ! tail & /rik+ ! w+s1 ! re> gu/ w r$uce ! velocity & cause a loss 9 lift4 ,?is w ei!r cause ! ma*9e to head dive or drop v]tically ?r\gh a c]ta9 di/ance until x aga9 assumes its normal velocity4 ,all ( ^! v>iations cause a cont9ually =e & aft upsett+ movem5t t mu/ be cont9ually correct$ by rais+ & l[]+ ! elevator flaps1 & 9 v gu/y wea!r ?is is a v t$i\s & we>+ job4 ,x requires ! cont9ual att5tion ( ! pilot unless ! action is p]=m$ automatically by "s me*anical device1 su* z ! ,sp]ry ,gyroscopic1 or else by "s arrangem5t ( ! surfaces t give inh]5t /ability4 ,control by means ( ! elevator flaps 7:i* raise & l[] ! body 9 a =e & aft direction1 z %[n7 is kn[n z longitud9al control1 & :5 ! ma*9e is s built t correction = ! longitud9al attitude is obta9$ inh]5tly1 ! ma*9e is said to be longitud9ally /able4 ,mod]n ma*9es c be made v ne>ly longitud9ally /able1 & are comp>atively unaffect$ by any ?an ! heavie/ gu/s4 99,lat]al ,/ability994 ,! gu/s also affect ! side to side1 or lat]al balance by caus+ a diff]5ce 9 lift on ei!r end ( ! w+s4 ,%\ld ! gu/ /rike "o tip be=e ! o!r1 or %\ld x /rike "o tip h>d] ?an ! o!r1 ! t5d5cy w be to turn ! ma*9e ov] sidewise4 ,?is is a m difficult problem to solve ?an ! longitud9al mom5t1 al?\gh p]fect inh]5t /ability has be5 atta9$ 9 "o or two ma*9es )\t ! use ( additional automatic control me*anism4 ,inh]5t lat]al /ability has always be5 att5d$ by a consid]able loss 9 ! effici5cy ( ! a]oplane & spe$ due to ! peculi> arrangem5ts 9 ! ma9 lift+ surfaces4 ,at pres5t we mu/ make a decision betwe5 effici5cy & /ability1 = "o feature mu/ be atta9$ at a sacrifice 9 ! o!r4 ,contr>y to ! g5]al op9ion1 p]fect /ability is n desirable1 = almo/ inv>iably x affects ! control ( a ma*9e & makes x difficult to maneuv]4 ,%\ld ! /ability appliances be arrang$ s t !y c be cut out ( action at w1 z 9 ! case ( ! ,sp]ry ,gyroscopic ,/abiliz]1 !y w fulfill ! ne$s ( ! aviator mu* m fully ?an ^? ( ! fix$ inh]5t type4 ,! fir/ ?or\ghly /able ma*9e1 bo? longitud9ally & lat]ally1 0 t design$ by ,lieut5ant ,dunne1 & ?is obta9$ its di/9ctive feature by a v peculi> arrangem5t ( ! w+ surfaces4 ,x 0 excessively /able1 & z ) all v /able ma*9es1 0 difficult to /e] 9 a /raight l9e 9 w9dy wea!r1 & 0 correspond+ly difficult to l&4 ,illu/ration3 ,fig4 #ab4;,a4 ,diagram ( ! ,tractor ,biplane ,! fir/ ma*9e ( ! ord9>y biplane type t prov$ inh]5tly /able 0 ! ,r4 ,e4-#a design$ 9 ,engl& by ,edw>d ,busk4 ,?is ma*9e 0 fl[n f ,f>nbor\gh to ,salisbury ,pla91 & dur+ ?is flight ! only control t\*$ 0 ! v]tical rudd] us$ 9 /e]+4 ,s9ce !n1 all ,engli% ma*9es h be5 made at lea/ p>tially /able1 ! degree dep5d+ ^u ! s]vice = :i* x 0 int5d$4 ,x has be5 f\nd t 9 fight+1 a v controllable ma*9e is necess>y1 h5ce /ability mu/ be sacrific$1 or ! control surfaces mu/ be made suffici5tly p[]ful to ov]come ! /able t5d5cy ( ! ma*9e4 ,w> ma*9es are made to be j com=tably /able ov] ! range ( ord9>y flight spe$s1 & ) controls p[]ful en\gh s t ! inh]5t /ability c be ov]come :5 maneuv]+ 9 battle4 ,! pres5t w> ma*9e always conta9s an elem5t ( dang] = ! unskill$ pilot4 99,dih$ral ,angle994 ,?is 0 ! fir/ lat]al /ability arrangem5t to be appli$ to an a]oplane1 b is only effective 9 /ill air4 ,9 r\gh wea!r its g5]al t5d5cy is to de/roy /ability by all[+ dang]\s oscillations to take place4 ,fig4 #ac is a front view ( a monoplane 9 :i* ! w+s 7w7 & 7w'7 are set at an angle 7d71 ?is angle be+ kn[n z ! dih$ral angle4 ,! dott$ l9e 7m-m7 %[s ! l9e ( a pair ( p]fectly horizontal w+s & aids 9 illu/rat+ ! dih$ral4 ,assum+ ! c5t] ( lift at ,,cl on ! w+s1 x w be se5 t an increase 9 ! dih$ral raises ! c5t] ( lift above ! c5t] ( gravity l9e ,c4 ,g4 by ! am\nt 7h74 ,) ! c5t] ( gravity bel[ ! c5t] ( lift x is evid5t t ! weight ( ! ma*9e w\ld t5d to keep x on a level keel1 al?\gh ! same effect c\ld1 ( c\rse1 be atta9$ 9 ano!r way4 ,! pr9cipal right+ effect ( ! dih$ral is %[n by ,fig4 #ad 9 :i* ! w+s 7w7 & 7w'7 are set z be=e4 ,! ma*9e is tipp$ or li/$ t[>d ! left 7se5 f aviator's seat7 s t w+ 7w'7 is d[n4 ,by draw+ v]tical l9es d[n until !y int]sect ! horizontal l9e ,x-,x 7! l9e ( equilibrium71 x w be se5 t w+ 7w'7 pres5ts m horizontal lift surface ?an 7w7 s9ce ! project$ or effective w+ l5g? 7,c7 is great] ?an 7b74 ,s9ce 7w'7 pres5ts ! great] surface1 ! lift 7,l7 t5ds to re/ore ! ma*9e to its orig9al level position4 ,if ! w+s 7 bo? set on ! same /raight l9e1 ! project$ l5g?s 7b7 & 7c7 w\ld be ! same & !re w\ld be no re/or+ effect4 ,! dih$ral w\ld be v effective 9 /ill air1 b 9 turbul5t air1 & ) ! body sw++ back & =?1 ! dih$ral w\ld act 9 ! nature ( a circul> guid+ pa?1 & ?us t5d to all[ ! sw++ to p]si/ or increase r ?an to damp x d[n1 z w\ld be ! case ) level /raight w+s4 ,aga91 ) ! w+ b5t up at a consid]able angle1 a side gu/ z at 7,s7 w\ld t5d to ?r[ ! ma*9e /ill fur!r ov]1 & ?us increase r ?an dim9i% ! difficulty4 ,9 practical ma*9es1 ! dih$ral is usually made v small 7d #agf degrees71 ! angle ( ea* w+ ) ! horizontal be+ ab\t #b degrees1 or ev5 less4 ,i ?9k ! advantage ( su* a small angle is r m imag9>y ?an actual1 & at pres5t ! great] numb] ( w> ma*9es h no dih$ral at all4 ,9 ! old] monoplanes ! angle 0 v pron\nc$4 ,fig4 #ae %[s ! dih$ral appli$ bo? to ! upp] w+ 7,u7 & ! l[] w+ 7,l71 ! usual me?od ( apply+ dih$ral to l>ge biplanes4 ,fig4 #af %[s ! me?od ( apply+ ! dih$ral to small1 fa/ ma*9es1 su* z spe$ sc\ts1 ! dih$ral 9 ?is case be+ us$ only on ! l[] w+4 ,! dih$ral on ! bottom w+ is usually = ! purpose ( cle>+ ! w+ tips :5 turn+ on ! gr\nd r ?an = /ability4 ,a l[] w+ ) a dih$ral is less likely to /rike ! gr\nd or to become f\l$ :5 x enc\nt]s a side gu/ 9 l&+ or gett+ (f4 ,! use ( /raight upp] w+s makes ! con/ruction mu* simpl]1 especially on ! small ma*9es :]e x is possible to make ! w+ 9 "o cont9u\s l5g?4 99,ail]ons & ,w+ ,w>p+994 ,s9ce ! dih$ral is n effective 9 produc+ lat]al /ability1 "s o!r me?od mu/ be us$ t is p[]ful en\gh to ov]come bo? ! upsett+ movem5ts & ! lat]al oscillations caus$ by ! p5dulum effect ( a l[ c5t] ( gravity4 ,9 ! ord9>y type ( a]oplane ?is right+ effect is p]=m$ by movable surfaces t increase ! lift on ! l[] w+ tip1 & decrease ! lift on ! high side4 ,9 ,"s cases ! lat]al control surfaces are sep>ate f ! w+ prop] 7,ail]ons71 & 9 "s ! tip ( ! w+ is twi/$ or w>p$ s z to produce ! same effect4 ,^! control surfaces may be op]at$ manually by ! pilot or by "s type ( me*anism1 su* z ! gyroscope1 al?\gh ! =m] is ! me?od mo/ us$4 ,! lat]al control1 or side to side balanc+ ( an a]oplane1 c be comp>$ to ! side to side balanc+ ( a bicycle 9 :i* ! unbalance is cont9ually1 be+ correct$ by ! movem5t ( ! h&le b>s4 ,fig4 #ag %[s ! control surfaces or ,ail]ons 7,a-,a'71 m\nt$ ne> ! tips1 & at ! re> edge ( ! w+ ,w4 ,z %[n1 !y are cut into & h+$ to ! ma9 w+s s t !y are free to move up & d[n ?r\gh a total angle ( ab\t #fj degrees4 ,9 a biplane !y may be fitt$ to ! upp] w+ alone or to bo? top & bottom w+s1 accord+ to conditions4 ,= simplicity we w consid] only ! monoplane 9 ! pres5t in/ance4 ,9 ,fig4 #ah1 a front view ( ! monoplane1 ! ma*9e is %[n heel$ ov] s t ! w+ tip 7w7 is l[4 ,to correct ?is displacem5t1 ! ail]on 7,a7 on ! l[ side1 is pull$ d[n & ! ail]on 7,a'7 on ! opposite end is pull$ up4 ,?is1 ( c\rse1 increases ! lift on ! l[ end 7w7 & decreases ! lift on ! high side 7w'74 ,! right+ =ces ex]t$ are %[n by ,l-,l'4 ,! increas$ angles made by ,a-,a' ) ! w9d /ream affects ! =ces act+ on ! w+s1 al?\gh 9 opposite directions1 caus+ a left h& rotation ( ! :ole ma*9e4 ,9 ,fig4 #ai1 conditions are normal ) ! ma*9e on an ev5 keel & ) bo? ail]ons br\ght back to a po9t :]e !y are level ) ! surface ( ! w+1 or 9 neutral4 ,fig4 #bj %[s ! ma*9e cant$ 9 ! opposite direction ) 7w'7 l[ & 7w7 high4 ,?is is correct$ by br++ d[n ail]on 7,a'7 & rais+ 7,a71 ! =ces ,l-,l' %[+ ! rotation direction4 ,by alt]nately rais+ & l[]+ ! ail]ons we c correspond+ly raise or l[] ! w+ tips4 ,x %\ld be not$ "h t 9 "s ma*9es ! ail]ons are only s+le act+1 t is1 ! ail]on on ! l[ side c be pull$ d[n to increase ! lift1 b ! opposite ail]on rema9s 9 ! plane ( ! w+s1 & does n t5d to pu% d[n ! high side4 ,s9ce all ( ! ail]on resi/ance 9 a horizontal direction is n[ conf9$ to ! l[ side1 x turns ! ma*9e f its pa?1 ! high w+ sw++ ab\t ! l[] tip ) ! latt] z a pivot4 ,9 ! d\ble act+ control z %[n 9 ,figs4 #ag to #bc1 ! resi/ance is ne>ly equal at bo? tips & h5ce !re is no t5d5cy to di/urb ! flight direction4 ,) s+le act+ ail]ons1 ! directional di/urbance is correct$ ) ! rudd] s t :5 ! ail]on is pull$ d[n x is necess>y to set ! rudd] to oppose ! turn4 ,on e>ly ,wright ma*9es ! rudd] & lat]al controls 7 int]connect$ s t ! rudd] automatically respond$ to ! action ( ! ail]ons4 ,fig4 #ba is a detail$ front elevation ( ! ma*9e & %[s ! control :eel 7,c7 & cable connections betwe5 ! :eel & ! ail]ons ,a-,a'4 ,:5 ! :eel ,c is turn$ 9 ! direction ( ! arr[ ,k1 ! ail]on ,a' is pull$ d[n by ! flexible cable 7i71 & a correspond+ am\nt ( cable 7h7 is paid (f ! :eel to ! ris+ ail]on ,a4 ,ail]on ,a is pull$ up by ! connect+ cable 7e7 :i* is atta*$ to ,a' at "o end & to ,a at ! o!r4 ,pulleys 7f7 & 7g7 guide ! int]connection cable4 ,on turn+ ! :eel 9 ! opposite direction1 ail]on ,a is pull$ d[n & ,a' is elevat$4 ,9 flight1 especially 9 r\gh wea!r1 !re is almo/ cont9u\s op]ation ( ! control :eel4 ,figs4 #bb & #bc are sections tak5 ?r\gh ! w+ ,w & ! ail]ons1 %[+ ! me?od ( h++ & travel4 ,fig4 #bb %[s ! ail]on depress$ = rais+ ! w+ 9 ! direction ( ,l1 :ile ,fig4 #bc %[s ! ail]on lift$ to l[] ! w+4 ,9 normal flight1 ) ! ma*9e level1 ! ail]on =ms a "p ( ! w+ outl9e 79 neutral position74 ,9 ! orig9al ,wright a]oplane1 & 9 ! majority ( monoplanes1 no ail]ons are us$1 ! re> ( ma9 w+ tip be+ b5t d[n bodily to increase ! lift4 ,?is is kn[n z w+ w>p+1 & is practically a s+le act+ process s9ce ! depress+ =ce on ! high tip is seldom z effective z ! lift on ! l[4 ,w>p+ is n g5]ally us$ on mod]n biplanes s9ce x is impossible to ma9ta9 a /rong rigid /ructure ) flexible tips4 ,! control w>p+ & twi/+ ( su* w+s soon loos5s !m up & de/roys :at rema9+ /r5g? !y may h _h4 ,illu/ration3 ,figs4 #ag-bc4 ,%[+ ,use ( ,ail]ons 9 ,ma9ta9+ ,lat]al ,balance4 99,bank+ & ,turn+994 ,9 mak+ a %>p turn ! out] w+ tip mu/ be elevat$ to prev5t slipp+ sidewise ?r\gh ! effects ( ! c5trifugal =ce 7side slip74 ,?is is kn[n z bank+4 ,! fa/] & %>p] ! turn1 ! /eep] mu/ be ! bank1 or ! angle ( ! w+s1 until 9 "s cases ( /unt fly+ ! w+s /& almo/ /raight up & d[n4 ,%\ld ! bank be too /eep !re w be an equal t5d5cy to slip d[n1 & inw>dly1 s9ce ! end resi/ance aga9/ side slip is v slight4 ,"s a]oplanes assume ! correct angle ( bank automatically )\t att5tion f ! pilot s9ce ! extra lift due to ! rapid motion ( ! out] tip causes x to rise4 ,on o!r ma*9es ! natural bank+ ef=t ( ! ma*9e is n suffici5t1 & ?is mu/ be increas$ by pull+ d[n ! ail]on on ! out] w+ tip4 ,ma*9es t h a t5d5cy to ov]-bank mu/ h ! ail]ons appli$ 9 ! rev]se direction s z to depress ! out] tip4 ,9 cases ( "u1 or ov]bank+ ma*9es x =m]ly requir$ exp]i5ce & judgm5t on ! "p ( ! pilot to obta9 ! correct bank+ angle4 ,!re are n[ bank+ indicators on ! m>ket t %[ :e!r ! ma*9e is correctly bank$ or is side-slipp+4 ,illu/ration3 ,fig4 #bd4 ,a ,dep]duss9 ,monoplane ,bank+ ,ar\nd a ,%>p ,turn at ,high ,spe$4 ,note ! ,elevation ( ! ,out] ,w+ ,tip & ! ,angle ,made ) ! ,horizontal by ! ,w+s4 ,spe$1 #aje ,miles ,p] ,h\r4 ,illu/ration3 ,/&>d ,h-#c ,tra9+ ,biplane4 ,,*apt] ,,ii4 ,,types ,,( ,,milit>y ,,a]oplanes4 99,divisions ( ,s]vice994 ,9 ! army & navy1 a]oplanes are us$ bo? = (f5sive & def5sive op]ations4 ,!y mu/ c>ry out _! own "w & int5tions & prev5t ho/ile craft f c>ry+ out !irs4 ,9 (f5sive op]ations ! ma*9es fly cont9u\sly ov] ! enemy's c\ntry & attack e ho/ile craft sight$1 ?us creat+ a dang] zone )9 ! enemy's l9es :]e no oppos+ ma*9e c "w )\t be+ ?reat5$ ) an ov]:elm+ attack4 ,! (f5sive also includes bomb+ op]ations & ! de/ruction ( supply depots & transportation c5t]s4 ,def5sive a]ial op]ation consi/s 9 driv+ out ! enemy craft f our own l9es1 & 9 protect+ work+ ma*9es :5 on photograph+ or obs]vation trips4 ,) a p[]ful (f5sive !re is ( c\rse little ne$ = def5se4 ,! =m] me?od is a co/ly "o1 & is productive ( sev]e mat]ial & p]sonal losses4 ,at ! pres5t "t !re are eight pr9ciple functions p]=m$ by milit>y a]oplanes3 #a4 ,(f5sive op]ations aga9/ enemy ma*9es4 #b4 ,reconnaissance1 obs]vation1 special missions4 #c4 ,bomb+ supply c5t]s1 railways1 etc4 #d4 ,photography4 #e4 ,spott+ = ! artill]y4 #f4 ,signall+ = infantry op]ations4 #g4 ,subm>9e hunt+4 #h4 ,patrol & b>rage4 ,illu/ration3 ,fig4 #a4 ,curtiss ,baby4 ,biplane ,spe$ ,sc\t4 ,equipp$ ) #ajj ,horsep[] ,wat] ,cool$ ,motor4 ,probably ! mo/ important s]vice ( all is p]=m$ by ma*9es "u head+ 7#a74 ,if a successful (f5sive c be ma9ta9$ ov] ! enemy's l9es he is unable to intellig5tly direct 8 artill]y fire1 & c obta9 no in=mation reg>d+ re9=cem5ts1 or troop conc5trations = an imp5d+ attack4 ,) fight+ a]oplanes cle>+ ! way = our own obs]vation ma*9es & artill]y spott]s1 ! enemy is n only bl9d$1 b is block$ 9 any attempt to attack or conc5trate 8 =ces4 ,! fact t ! ,fr5* a]ial (f5sive at ,v]dun 0 s effici5tly & well ma9ta9$ acc\nts = ! failure ( ! heavy ,g]man artill]y4 ,driv5 f> back ov] _! own l9es1 ! ,g]man aviators 7 seldom able to obs]ve ! plac+ ( ! %ells1 & z a result _! gunn]s 7 practically tru/+ to luck 9 rea*+ _! t>get4 ,an imm$iate & accurate bomb>dm5t always foll[$ "o ( ! v infrequ5t ,g]man air raids ov] ! ,fr5* l9es4 ,:5ev] ! ,fr5*1 p>tially ab&on$ _! a]ial (f5sive 9 favor ( a def5sive campaign1 !y soon lo/ _! ma/]y ( ! air4 ,z long z enemy ma*9es c be kept back ( _! own l9es1 new tr5* sy/ems c be con/ruct$1 transportation l9es c be ext5d$ & ammunition dumps arrang$1 und]tak+s t w\ld be highly prec>i\s ) enemy obs]vation ma*9es cont9ually pass+ ov]head4 ,illu/ration3 ,fig4 #a4 ,italian ,pomilio ,two ,seat] ,biplane4 ,c\rtesy ,fly+4 ,to ma9ta9 an effective (f5sive places a trem5d\s /ra9 on bo? ! m5 & ! ma*9es1 = ?\gh ! a]oplanes d n p5etrate f> beyond ! l9es !y usually meet ) sup]ior numb]s1 & 9 addition are cont9ually 9 range ( ! anti-aircraft guns4 ,9 an attack ov] ho/ile c\ntry a slight mi%ap may cause ! loss ( a 'plane1 = usually ! di/ance f its base is s great z to prev5t a glid+ return4 ,ov] its own l9es an eng9e failure is usually only a tempor>y inconv5i5ce4 ,fight+ a]oplanes1 = ! (f5sive1 are small high p[]$ ma*9es g5]ally ( ! s+le seat] type1 & are capable ( high horizontal & climb+ spe$s4 ,! armam5t consi/s ( a ma*9e gun ( ! ,lewis type1 & occasionally a few light bombs may be includ$ 9 ! equipm5t4 ,z !y d n c>ry out op]ations f> to ! re> ( ! enemy's l9es !y are provid$ ) fuel = only two or ?ree h\rs1 & ?is r$uc$ fuel load is necess>y = ! high spe$s t mu/ necess>ily be atta9$4 ,! area is limit$ to p]mit ( quick maneuv]s 9 attack & escape1 & at ! same "t to r$uce ! head resi/ance & weight4 ,! horizontal spe$ may run up to #aej miles p] h\r1 ) a climb+ velocity t may exce$ #a1jjj feet p] m9ute4 ,su* ma*9es are v>i\sly kn[n z ,spe$ ,sc\ts1 ,*as]s1 or ,pursuit ,type 7,fr5* ,de,chasse74 ,at ! beg9n+ ( ! w> ! *as]s 7 l>gely ( ! monoplane type1 b at pres5t ! biplane is 9 almo/ exclusive use4 ,illu/ration3 ,fig4 #b4 ,ma*9e ,gun ,m\nt+ on ,morane ,monoplane4 ,gun ,fires ,directly ,?r\gh ! ,propell] ,disc4 ,! ,deflect+ ,plate ,atta*$ to ! ,root ( ! ,propell] ,blade ,protects ! ,propell] ,:5 9 ,l9e ( ,fire4 ,ammunition 9 ,?is ,gun ,is ,furni%$ 9 ,/raight ,/rips or ,clips4 ,! a]oplane employ$ = surveys ( ! enemy c\ntry & battle front 7#b7 are ( an entirely diff]5t type & are mu* l>g] & sl[]4 ,^! ,reconnaissance ma*9es are g5]ally ( ! two-seat] type1 ! p]sonnel consi/+ ( an obs]v] & ! pilot1 al?\gh 9 "s cases a ?ird man is c>ri$ z an assi/ant to ! obs]v]1 or to h&le a ma*9e gun aga9/ an attack4 ,s9ce _! spe$ is comp>atively l[1 !y are g5]ally provid$ ) an escort ( *as]s1 especially :5 employ$ on di/ant missions1 ?is escort repell+ attacks :ile ! obs]vations are be+ made4 ,illu/ration3 ,fig4 #b-;a4 ,ma*9e ,gun ,m\nt+ on ,s4 ,p4 ,a4 ,d4 ,biplane4 ,gun ,is ,rigidly ,atta*$ to ,fuselage ,top 9 ,front ( ,pilot4 ,= accurate obs]vation & mapp+1 ! spe$ ( an obs]vation ma*9e mu/ be necess>ily l[1 & z !y are additionally burd5$ ) a wireless set1 an obs]v]1 a l>ge fuel res]ve1 & o!r imp$im5ta1 !y h a comp>atively great area & are !re=e lack+ 9 ! maneuv]+ qualities ( ! *as]4 ,! span w av]age ab\t #dj feet1 & ! weight c>ri$ p] horsep[] is greatly 9 excess ( t ( ! *as]4 ,f a numb] ( examples1 ! reconnaissance type w av]age f #af to #ah p\nds p] horsep[]1 :ile ! load+ ( ! sc\t is f #h to #ab4 ,?is means t ! =m] has comp>atively little res]ve p[] = rapid climb+4 ,! pres5t reconnaissance type is always arm$1 & mu/ n be confus$ ) ! e>ly ma*9e by t "n1 :i*1 9 fact1 0 m]ely an enl>g$ tra9+ ma*9e & _h nei!r (f5sive nor def5sive p[]s4 ,! ,obs]v] acts z gunn]1 & is locat$ at a po9t :]e he has ! greate/ possible range ( vision1 & :]e ! angle ( fire is z little ob/ruct$ z possible4 ,! radius ( action1 or ! di/ance travel$ p] tank ( fuel1 is great] ) ! reconnaissance ?an ) ! *as]1 pres5t ma*9es hav+ a capacity ( f #aj to #ab h\rs on a s+le fill+ at normal flight spe$4 ,9 bomb+ op]ations 7#c71 ! load+ is v heavy & consequ5tly a ,bomb] mu/ be a weight lift] to ! exclusion ( all o!r qualities4 ,n only is ! bomb load requirem5t sev]e1 b ! fuel load is also ( great importance1 s9ce bomb+ is usually c>ri$ out at consid]able di/ances f ! base4 ,su* ma*9es may c>ry f ?ree to six m54 ,all ?is calls = a trem5d\s area & a l>ge p[] plant4 ,! ,h&ley-,page ,giant1 & ! ,caproni ,triplane are examples ( ,alli$ ma*9es ( ?is type :ile ! ,g]man ,go?a1 us$ 9 ! ,london air raids1 is an equival5t enemy ma*9e4 ,z an example ( ! weight c>ry+ capacity ( a typical bomb]1 ! ,h&ley-,page has c>ri$ a te/ crew ( #ba m51 or a p]sonnel load ( #c1egj p\nds4 ,! total weight1 fully load$1 has be5 giv5 z #aa1ejj p\nds ) a p[] plant ( #edj horsep[]4 ,! maximum spe$ is #ij miles p] h\r ) a climb+ velocity ( ab\t #ccj feet p] m9ute4 ,duration is ab\t #e h\rs at normal spe$ & full load4 ,illu/ration3 ,fig4 #c4 ,h&ley-,page ,giant ,bomb+ ,type ,biplane4 ,c\rtesy ,! ,a]oplane4 ,illu/ration3 ,fig4 #d4 ,curtiss ,tw9 ,motor ,biplane-,type ,,jn4 ,bomb+ is ( great importance1 n only because ( ! damage caus$ to munition factories1 transportation l9es1 /ore h\ses1 etc41 b also because ( ! moral effect on bo? ! enemy troops & ! civil population4 ,a well-tim$ bomb+ raid w d m to disorganize an army ?an almo/ any o!r =m ( attack1 & ?is is att5d$ ) a mu* less loss ( life1 & ) less co/ & equipm5t4 ,po9ts 9 enemy t]ritory t c\ld be rea*$ 9 no o!r way are readily attack$ by bomb+ planes ) all ! disa/r\s effects ( heavy artill]y fire4 ,! a]oplane is bett] adapt$ = ?is s]vice ?an dirigibles ( ! ,zeppel9 type1 = !y require few] m5 = _! op]ation1 & 9 addition co/ less to op]ate & build4 ,illu/ration3 ,fig4 #d;a4 ,curtiss ,wireless ,spe$ ,sc\ts 7,s-#b74 ,by an ,+5i\s ,arrangem5t ( ! ,int]plane ,/ruts ,!re ,is ,no ,expos$ ,wire or ,cable4 ,bomb+ op]ations aga9/ well protect$ objectives are be/ made at night s9ce !re is less *ance ( loss ?r\gh anti-aircraft gun fire1 & also because ( ! difficulty t ! def5se ma*9es h 9 locat+ ! raid]s4 ,ev5 :5 well equipp$ ) se>*lights & li/5+ /ations1 x is n ! easie/ ?+ 9 ! _w to pick out & hold ! location ( an attack+ squadron1 = ! se>*lights imm$iately betray !mselves & c !n be put out ( action by fire f ! invad]s4 ,) ! se>*lights out ( commission1 x is almo/ impossible = ! def5d+ *as]s to locate & engage ! raid]s1 ev5 be=e ! bombs h be5 dropp$4 ,aft] ! bomb dropp+ has be5 accompli%$ 7& ) comp>ative accuracy because ( ! fl>es dropp$ by ! bomb+ p>ty71 ! raid]s are light5$ ( a consid]able portion ( _! load1 & are correspond+ly increas$ 9 _! ability to climb & to evade ! enemy *as]s4 ,illu/ration3 ,fig4 #e4 ,sop) ,spe$ ,sc\t or ,*as]4 ,illu/ration3 ,fig4 #f4 ,nieuport ,biplane ,sc\t ) ,ma*9e ,gun ,pivot$ ,above ! ,upp] ,w+4 ,?is ,gun ,fires ,above ! ,propell]4 ,night fly+ 9 squadrons always introduces ! dang] ( collision1 & to m9imize ?is dang]1 by decreas+ ! numb] ( ma*9es1 ! size & c>ry+ capacity ( ! bomb]s has be5 cont9ually increas$4 ,aga91 bomb+ requires ! /eady plat=m t only a l>ge ma*9e c give1 & = accuracy ! span & area mu/ be great] ?an t ( ! reconnaissance type4 ,9 night fly+ a l>ge ma*9e is saf] to h&le ow+ to its l[] l&+ spe$ & ability to come to re/ quickly aft] l&+1 & ?is is ( ! greate/ importance :5 l&+ outside ( ! a]odrome4 ,= daylight "w at comp>atively %ort di/ances ! small] bomb c>ri] us$ at ! beg9n+ ( ! w> is probably pref]able z x has bett] maneuv]+ qualities1 & z ! bombs are divid$ among a great] numb] ( ma*9es !y are n s likely to be defeat$ be=e accompli%+ _! object4 ,because ( _! great size1 ^! bomb+ a]oplanes are ne>ly always ( ! tw9 motor type ) two1 or ev5 ?ree1 indep5d5t p[] plants4 ,! use ( a tw9 p[] plant is an add$ insurance aga9/ =c$ l&+s 9 ho/ile c\ntry1 or ov] unsuitable gr\nd1 & ev5 ) "o dead eng9e ! ma*9e c be fl[n home at a fair spe$4 ,illu/ration3 ,fig4 #h4 ,fokk] ,syn*roniz$ ,ma*9e ,gun4 ,! ,gun ,is ,driv5 by ! ,motor 9 ,su* a ,way ,t ! ,bullets ,pass ,betwe5 ! ,propell] ,blades4 ,l',a]ophile4 ,spott+ = ! guidance ( ! artill]y is a duty usually p]=m$ by ! reconnaissance type1 or small bomb+ type1 & is usually done "u ! escort ( *as]s4 ,_! duty is to direct ! batt]y z to ! plac+ ( %ots4 ,! ideal ma*9e = su* a purpose w\ld be ! direct lift type simil> to a helicopt] :i* c\ld hov] ov] "o p>ticul> spot until its object _h be5 accompli%$ 9 mak+ measurem5ts1 & plott+ enemy positions4 ,s9ce no su* ma*9e is at pres5t available1 ! duty mu/ be p]=m$ by a l[ spe$ a]oplane1 t is l>ge en\gh to provide a fairly /eady plat=m & at ! same "t has suffici5t spe$ = a quick getaway4 ,a dirigible has ! necess>y hov]+ qualities b lacks ! spe$ necess>y = avoid+ attack f ev5 ! sl[e/ ( a]oplanes1 & 9 addition is a magnific5t t>get = anti-craft guns if kept at an altitude l[ en\gh = accurate obs]vation4 ,a l>ge spe$ range is a desirable *>act]i/ic 9 su* s]vice4 ,photography is ( ! greate/ importance 9 reconnaissance1 s9ce ! cam]a di/9ctly records objects on ! t]ra91 s small & obscure t !y may entirely escape ! eye ( ! obs]v]4 ,aga91 ! photograph is a p]man5t record t may be /udi$ at leisure 9 headqu>t]s1 or may be us$ 9 comp>isons ) photographs tak5 at an e>li] date 9 ! same t]ritory4 ,?us *anges 9 ! disposition ( enemy batt]ies1 tr5*es1 & troops c be quickly id5tifi$4 ,) mod]n a]oplane photographic equipm5t1 a va/ t]ritory may be inve/igat$ & mapp$ out by a s+le ma*9e 9 a few h\rs4 ,cam\flage has b few t]rors = ! cam]a1 & ! photographs (t5 cle>ly reveal t :i* has be5 pass$ ov] "t & "t aga9 by ! obs]v]s4 ,:5 s5t out on a specific mission1 ! a]oplane returns ! films 9 an amaz+ly %ort l5g? ( "t1 & )9 a few m9utes !y are develop$ & are ready = ! inspection ( ! (fic]s 9 *>ge4 ,! analysis ( ^! photographs has rapidly develop$ into a sci5ce well wor?y ( a ,%]lock ,holmes4 ,*anges 9 ! position ( %ad[s1 suspici\sly sudd5 gr[?s ( und]bru%1 *anges 9 ! direction ( pa?s1 & fre% m\nds ( e>? all h a def9ite mean+ to ! photographic exp]t4 ,illu/ration3 ,fig4 #i4 ,types ( ,a]oplane ,bombs4 ,! ,tail ,surfaces ,guide ! ,bomb ,s ,t ,x ,/rikes on ! ,fir+ ,p9 & at ! ,same ,"t ,safeties ! ,bomb ,s ,t x ,w ,n ,explode ,until x ,has ,fall5 = ,"s ,di/ance4 ,9 ,fall+1 ! ,tail ,blades ,rotate & ,release ! ,fir+ ,me*anism ,aft] ! ,bomb ,has ,fall5 ,cle> ( ! ,a]oplane4 ,c\rtesy ( ,fly+4 ,illu/ration3 ,fig4 #i-;a4 ,curtiss ,,jn ,tw9 ,motor ,biplane4 ,obs]v] ,is ,seat$ 9 ,front4 ,9 ! navy ! a]oplane has prov$ ( mu* value 9 sc\t+ & p>ticul>ly 9 def5se aga9/ ! subm>9e4 ,because ( its great spe$ x has a daily radius ( action _m times t ( a torp$o boat1 & because ( its altitude ! effective range ( vision is /ill fur!r increas$4 ,at a fair height ! obs]v] c easily detect a subm>9e ev5 :5 subm]g$ to a consid]able dep?1 a feat impossible :5 ne> ! sea level4 ,= disclos+ ! conditions exi/+ 9 an enemy h>bor ! a]oplane is fully ! equal ( ! dirigible s9ce x c approa* & retreat rapidly1 & )\t mu* dang] at comp>atively l[ altitudes4 ,:ile ! dirigible c float indef9itely at "o po9t1 x mu/ be done at an altitude t is safely out ( range ( ! enemy guns1 & ?is is usually at a po9t :]e obs]vation is a difficult proposition4 ,x does n take long to get ! range ( su* a t>get z a hov]+ dirigible1 yet at a mu* l[] altitude x is difficult to h&le naval anti-aircraft guns effectively aga9/ a spe$+ a]oplane4 ,! small] sc\t+ seaplanes c report ! position ( a subm>9e to a torp$o boat or sub-*as]1 :ile ! l>g] ma*9es are p]fectly capable ( deal+ ) ! subm>9e at fir/ h&4 ,on ! l>ge bomb+ type1 a ?ree-p\nd] gun & a numb] ( l>ge bombs c be c>ri$1 ei!r ( :i* w\ld be suffici5t = ! purpose4 ,illu/ration3 ,fig4 #aj4 ,explosion ( a ,g]man ,a]oplane ,bomb ,ne> ,mesopotamia4 ,c\rtesy ( ,fly+4 ,9 l& def5se *as]s & fight]s are us$ = patrol1 & to ma9ta9 a b>rage aga9/ ! entrance ( enemy ma*9es into our l9es4 ,! patrol ma*9es "w along ! front l9e tr5*es1 :ile ! ma*9es ma9ta9+ ! b>rage are g5]ally arrang$ 9 two p>allel l9es back ( ! tr5*es1 ! fir/ be+ ab\t five miles1 & ! second ab\t t5 miles f ! front4 ,all ?ree l9es are g5]ally plac$ betwe5 ! enemy & ! pr9cipal /ations & railroad c5t]s to insure protection f enemy bomb]s & reconnaissance ma*9es4 ,%\ld ! fir/ l9e patrol fail to keep raid]s f cross+ ! fir/ l9e tr5*es1 !y w h to pass ?r\gh at lea/ two m zones ( organiz$ fight+ squadrons be=e rea*+ a vuln]able spot 9 our l9es4 ,! ma*9es us$ = patrol & b>rage are ( ! high spe$ & fa/ climb+ *as] type4 ,! response to an attack involves rapid climb+1 & a high degree ( maneuv]+4 ,illu/ration3 ,fig4 #aa4 ,caproni ,triplane ) ,?ree ,indep5d5t ,p[] ,plants4 ,! ,motor 9 ! ,c5tral ,body ,drives a ,pu%] ,propell]1 ,:ile ! ,o!r ,p[] ,plants ,are ,m\nt$ 9 ! ,two ,out] ,bodies & ,drive ,tractor ,screws4 ,?is is an ,example ( ! ,l>g] ,bomb+ ,a]oplanes4 ,! ,gun ,is ,m\nt$ 9 ! ,front ( ! ,c5t] ,body4 ,c\rtesy ,! ,a]oplane4 ,except = ! bomb]s & battle planes1 ! ma*9e gun or ,mitraleuse has be5 ! only =m ( arm 9 common use on a]oplanes4 ,^! use ammunition approximat+ s]vice rifle calib] & are furni%$ 9 b&s1 /rips or drums accord+ to ! type ( gun4 ,) l>g] guns1 ! weight ( ! ammunition has be5 f\nd excessive ) all b ! l>ge/ bomb+ ma*9es1 & ! recoil ( a l>ge calib] gun has also be5 difficult to ov]come4 ,9 a mod]n ,am]ican a]oplane gun ( l>ge calib] ! recoil has be5 r$uc$ to almo/ a negligible degree1 ev5 up to ! f\r-p\nd] size1 by a sy/em ( balanc$ projectile reactions4 ,?is gun has met successful te/s1 b :e!r x has met ) g5]al adoption w\ld be difficult to say at ! pres5t "t4 ,9 ,europe1 l>ge calib] a]oplane guns h be5 us$ on l>ge battle planes or gun planes = %ell+ dirigibles1 or 9 de/roy+ se>*light /ations 9 bomb+ raids4 ,! battle planes are ne>ly always ( ! ,tw9 type ) ! gun m\nt$ 9 ! front end ( ! fuselage4 99,summ>y ( ,types994 ,to sum up ! types requir$ 9 milit>y op]ations1 we h3 7#a7 ,high spe$ ,*as] or ,sc\t 7,s+le seat]71 7#b7 ,high spe$ ,*as] 7,two-seat type71 7#c7 ,reconnaissance type1 7#d7 ,bomb+ type1 7#e7 ,gun or ,battle ,planes4 ,?is does n include ! tra9+ ma*9es ( ! two place & ,p5gu9 types1 b z ^! are simply un>m$ modifications ( ! two place reconnaissance & s+le seat ma*9e1 respectively1 we w n g into fur!r details at ?is po9t reg>d+ _! con/ruction4 99,! ,*as] or ,pursuit ,type994 ,! mo/ important factors 9 ! design ( a *as] are spe$ & maneuv]+ ability4 ,! spe$ mu/ be at a maximum 9 bo? ! horizontal & v]tical directions1 = climb+ ability is fully ( z mu* importance z horizontal spe$4 ,second 9 importance is ! maximum altitude or ,height ( ceil+ to :i* ! ma*9e c asc5d4 ,?is maximum ,ceil+ g5]ally goes h& 9 h& ) ! climb+ spe$1 s9ce a fa/ climb] g5]ally has a correspond+ly high maximum altitude4 ,! comb9ation ( weight & head resi/ance mu/ be su* t ! climb int]f]es z little z possible ) ! =w>d velocity4 ,illu/ration3 ,de ,havill&4 ,v4 ,s+le ,seat ,*as] or ,spe$ ,sc\t ) a ,s+le ,rigidly ,m\nt$ ,ma*9e ,gun on ,top ( ,hood 7,to ,left74 ,x w ,be ,not$ ,t ! ,top ,w+ is ,/agg]$ ,back ,in/ead ( ,=w>d z 9 ! ,usual ,type1 ,?us ,all[+ ! ,pilot to ,look ,directly ,up & 9 ,front ( ! ,top ,w+4 ,dim5sions ,are 9 ,millimet]s4 ,great climb+ ability means a l>ge p[] res]ve1 h5ce ! weight c>ri$ p] horsep[] is r$uc$ to f #h to #ab p\nds on ! fa/e/ ma*9es1 aga9/ ! #af to #ah p\nds c>ri$ on ! l>g] & sl[] reconnaissance types4 ,/r5g? mu/ be sacrific$ to meet ^! conditions1 s t in/ead ( hav+ a safety factor ( f #h to #ab z 9 ! l>g] ma*9es1 x is cut to ab\t #e4e1 or 9 o!r words1 ! /r5g? is relatively only half t ( ! usual type ( a]oplane4 ,?is great r$uction 9 /r5g? calls = c>eful h&l+1 especially 9 l&+1 & also pa9/ak+ c>e 9 ! design & *oice ( mat]ials4 ,high spe$s & maneuv]+ ability bo? call = small w+ areas & %ort spans1 ! areas be+ s adju/$ t ! resi/ance is at a m9imum at ! highe/ spe$s4 ,! %ort spans h a m9imum ( expos$ int]plane brac+ & ?us indirectly r$uce bo? ! head resi/ance & ! weight4 ,un=tunately1 ! mo/ favorable areas at high spe$s are too small = safe l&+ spe$s4 ,) a fix$ area1 ! m9imum l&+ spe$ is only a little less ?an "o-half ( ! maximum fly+ spe$1 h5ce ) a maximum ( #aej miles p] h\r ! m9imum w probably be little less ?an #gj miles p] h\r4 ,! mo/ effici5t w+ sections1 & ! greate/ ref9em5t 9 ! body design1 brac+1 & *assis are necess>y at spe$s ( ov] #ajj miles p] h\r4 ,all o!r conditions be+ equal1 ! resi/ance v>ies z ! squ>e ( ! velocity1 h5ce at #aej miles p] h\r1 ! resi/ance is #b4be times t at #ajj miles p] h\r4 ,! foll[+ table gives approximately ! apportionm5t ( ! head resi/ance produc+ items 9 a typical spe$ sc\t or *as]4 ,body 7,fuselage7 #fh p] c5t ,*assis1 :eels1 /ruts1 etc4 #ae p] c5t ,tail1 rudd]1 f91 elevator #e p] c5t ,w+ /ructure1 /ruts1 wire1 fitt+s4 #ab p] c5t ,! a]odynamic drag due to ! lift ( ! w+s is n includ$ 9 ! above1 ! useless or p>asitic resi/ance alone be+ consid]$4 ,x w be not$ t ! body causes by f> ! great] "p ( ! resi/ance1 & z a result1 ! body ( ! spe$ sc\t requires ! mo/ c>eful att5tion 9 reg>d to /reaml9e =m4 ,=tunately ?is is possible ) ! %ort /umpy body ( ! *as]1 s9ce a true /reaml9e =m approximates ! av]age body dim5sions ( ! sc\t4 ,9 ! l>g] ma*9es1 ! body resi/ance is n z great 9 proportion to ! o!r items s9ce !re are m /ruts & /ay wires1 ! *assis is l>g]1 & ! tail surfaces are ( great] area4 ,! *assis is ! next l>ge/ item & is "o ( ! mo/ difficult items to r$uce4 ,x has be5 sugge/$ by sev]al p t ! *assis c\ld be /or$ away 9 ! body :ile 9 flight1 b ?is adds additional me*anism & weight1 & any automatic me*anism = fold+ up ! *assis memb]s w\ld likely prove unreliable4 99,*as] ,armam5t994 ,a s+le seat *as] is provid$ ) "o or two ma*9e guns m\nt$ on top ( ! fuselage1 & directly 9 front ( ! pilot1 ! l5g? ( ! b>rel be+ p>allel ) ! =e & aft c5t] l9e4 ,!y may ei!r be fix$ rigidly to ! fuselage top1 or s t !y c be po9t$ up1 & ov] ! top ( ! upp] w+4 ,) ! ma*9e guns fix$ rigidly to ! body1 z 9 ! e>ly *as] monoplanes us$ by ,g>ros & ,v$r9es1 x 0 necess>y at all times to fire directly ?r\gh ! disc area swept out by ! propell]4 ,two plans 7 tri$ = prev5t+ ! propell] f be+ brok5 by ! bullets4 ,! fir/ consi/$ ( a device op]at$ by ! motor t /opp$ ! gun :5ev] ! propell] blade came )9 ! pa? ( ! bullets4 ,?is e>ly me*anism prov$ unreliable1 s9ce ! frequ5t /opp+1 ) ! propell]s runn+ #abjj revolutions p] m9ute1 soon put ! app>atus out ( ord]4 ,soon aft] ! failure ( ?is me?od1 design]s m\nt$ curv$ protective /eel plates on ! inn] portions ( ! propell] blades at po9ts :]e !y 7 likely to be /ruck ) bullets4 ,accord+ to calculations 9 probability & *ance1 only "o bullet out ( e eighte5 w /rike ! protective plate on ! propell] blade1 & h5ce only "o out ( eighte5 bullets w be wa/$4 ,?is1 h[ev]1 0 a make%ift1 & on mod]n ma*9es ! gun is driv51 or ,syn*roniz$ ) ! motor s t ! bullets pass betwe5 ! blades4 ,illu/ration3 ,curtiss ,biplane 9 ,flight4 ,tak5 f ,ano!r ,ma*9e4 ,c\rtesy ,a]ial ,age4 ,_m mod]n s+le seat *as]s h ! gun pivot$ to ! top ( ! fuselage s t ! pilot c fire above ! top plane & to ei!r side ( ! body4 ,?is does away ) ! difficulty ( keep+ ! ma*9e head$ directly at ! enemy :5 9 action1 a me?od t is imp]ative ) ! fix$ type ( gun4 ,two seat] *as]s are g5]ally arrang$ s t ! gunn] is seat$ back ( ! pilot1 & ! gun is s pivot$ & support$ t x c be swung ?r\gh a wide radius bo? t[>d ! front & on ei!r side4 ,?is fre$om ( gun action at lea/ p>tly comp5sates = ! sl[] maneuv]+ qualities ( ! two seat] type1 s9ce ! gun may be swung ) ! t>get ?r\gh q a range ( field1 & )\t *ang+ ! flight direction ( ! ma*9e4 ,a gun ( ?is type is provid$ ) /ops :i* prev5t ! gunn] f %oot+ into ! outly+ p>ts ( 8 own ma*9e4 ,! gun m\nt+ 9 _m cases ( two seat] con/ruction consi/s ( a light circul> track t runs ar\nd ! edge ( ! cockpit op5+4 ,! gun /&>d runs on ?is track1 & ! gun is pivot$ at ! upp] end ( ! /&>d s t ! muzzle c be rais$ or l[]$4 ,! gun turns 9 a horizontal plane by slid+ on ! track1 & c be foll[$ ar\nd by ! gunn] :o is seat$ 9 ! c5t] on a pivot$ seat4 ,) ?is m\nt+ x is possible to gu>d aga9/ a re> attack1 to %oot /raight up1 or ne>ly /raight d[n ov] ! sides ( ! fuselage4 ,9 a few ma*9es ( ! two seat] type1 two ma*9e guns are provid$1 "o pivot$ gun 9 ! re>1 & "o gun rigidly fa/5$ to ! fuselage 9 front ( ! pilot4 ,x is v seldom t bo? guns c be br\ght into action at once unless engag$ ) a numb] ( enemy ma*9es1 al?\gh ! front gun is h&y 9 pursuit1 & at a "t :5 ! re> gun is ineffective because ( ! pilot 9 front ( him4 ,ev5 ) ! d\ble equipm5t1 ! sup]ior maneuv]+ qualities ( ! s+le seat] makes matt]s m ev5 ?an w\ld commonly be suppos$4 ,an add$ advantage ( ! s+le seat] is t x is small] & !re=e m difficult to hit4 ,engli% spe$ sc\ts h l>gely adopt$ ! ,am]ican ,lewis gun4 ,! c>tridges 9 ?is gun are arrang$ radially 9 a circul> drum1 & are f$ to ! gun z ! drum revolves4 ,! drum is m\nt$ on ! b>rel ne> ! bree* & is op]at$ automatically by ! successive explosions4 ,?is fe$s ! c>tridges & rejects ! empty %ells )\t ! att5tion ( ! pilot4 ,x fires ab\t #fjj %ots p] m9ute4 ,:5 "o drum is exhau/$1 ano!r drum ( new c>tridges c be quickly & easily ins]t$4 ,! ,fr5* use ! belt sy/em to a l>ge ext5t4 ,9 ?is sy/em ! c>tridges are atta*$ side by side on a cotton web belt z 9 ! old] types ( army ma*9e guns4 ,z 9 ! ,lewis gun1 ! c>tridges are f$ automatically by ! recoil ( ! explosions1 & ! belt moves ?r\gh ! bree* ) a /ep by /ep movem5t until ! ammunition is exhau/$4 ,?is is n ne>ly z compact an arrangem5t z ! ,lewis gun1 & is m difficult to pivot on acc\nt ( ! dangl+ belts4 ,on ! "r h& side ( ! ,nieuport body !re is a drum on :i* ! belt ) ! load$ c>tridges is w\nd4 ,! empty end ( ! belt is w\nd on a drum at ! left1 ?is drum be+ provid$ ) a spr+ to keep ! belt taut4 ,! empty c>tridges are dis*>g$ ?r\gh a tube t passes ?r\gh ! side ( ! body4 ,on ! #aiaf ,fokk] ! gun is ( ! ,maxim type1 & is immovably fa/5$ above ! eng9e c[l & slightly to ! "r4 ,to fire ! gun1 ! pilot presses d[n a small lev] fa/5$ to ! control column1 & f ?is lev] ! connect+ ,b[d5 wire closes ! motor clut* & />ts ! gun4 ,a cam is fix$ to ! motor %aft 9 relation to ! propell] blades4 ,:5 fir+1 ! elevator control is lock$ =e & aft1 :ile ! lat]al control movem5t is op]at$ by ! pilot's knees4 ,/e]+ is by ! action ( 8 feet on ! rudd] b>4 ,?us ! pilot c balance lat]ally1 & /e] ) 8 h&s free = ! manipulation ( ! gun1 b he _c *ange 8 elevation4 ,illu/ration3 ,a]om>9e ,tra9+ ,seaplane 99,p[] ,plant ( ! ,*as]994 ,9 ! small] spe$ sc\ts1 ! motor is ( ! rot>y air cool$ type1 ! output rang+ f #hj to #aaj horsep[]1 b z ! p[] dem&s increas$ ! wat]-cool$ motor came into use1 & at ! pres5t "t has f\nd favor ) a l>ge numb] ( build]s4 ,:5 ! p[] exce$s ab\t #abj horsep[] x is difficult to ?or\ghly cool ! rot>y eng9e1 & al?\gh ! ,gnome1 ,cl]get & ,le ,rhone are extremely desirable on a *as] because ( _! light weight1 !y _c be us$ pr(itably on ! l>g] sc\ts4 ,up to ! pres5t "t1 ! ,nieuport & ,sop) use ! ,cl]get & ,le ,rhone rot>y motors1 b ! ,s4 ,p4 ,a4 ,d4 & sev]al o!rs h adopt$ ! wat]-cool$ type4 ,ne>ly all ( ! ,g]man *as]s1 su* z ! ,rol& & ,albatros1 are wat]-cool$4 ,su* motors mu/ weigh well bel[ #c p\nds p] horsep[] if !re is to be suffici5t p[] res]ve = fa/ climb+4 ,! ,curtiss sc\ts are also wat]-cool$1 al?\gh ! rat+ is only #ajj horsep[]4 ,! ,fr5* & ,g]man ma*9es are v heavily p[]$1 motors ( #age horsep[] be+ v common1 ev5 on s+le seat]s4 ,! fuel capacity is v limit$1 probably n exce$+ #b4e to #c h\rs 9 any case4 99,g5]al ,dim5sions ( ,sc\ts994 ,! foll[+ table w give a bett] idea ( ! pr9cipal *>act]i/ics ( ^! ma*9es4 ,x gives ! ov]all dim5sions1 p[]1 spe$1 climb1 etc4 ,x w be not$ t ! ,nieuport biplane sc\ts h a small] l[] *ord 79974 ,! spe$s giv5 are ! sea level spe$s s9ce a great *ange 9 altitude affects ! p]=mance to a m>k$ degree4 99,reconnaissance ,type ,arrangem5t994 ,^! ma*9es are almo/ inv>iably ( ! two seat] type1 & are equipp$ ei!r ) "o ma*9e gun = ! obs]v]1 or ) a rigidly fix$ gun = ! pilot & a pivot$ gun at ! re> = ! obs]v]4 ,9 ! majority ( cases ! obs]v] is seat$ 9 ! re> cockpit 7,tractor types71 & at a po9t :]e he has a great] visual radius & field ( fire4 ,) ! pu%] type1 ! obs]v] is1 ( c\rse1 seat$ 9 ! extreme front ( ! body1 :]e he has an extremely wide angle ( vision4 ,! pilot 9 ! re> seat ( ! pu%] is effectually scre5$ f any gun action1 ei!r f ! front1 side or re>1 z ! propell] cuts (f ! field at ! back & ! obs]v] & int]plane brac+ blocks ! way at ! front & sides4 ,! obs]v]'s cock-pit is equipp$ ) ! signall+ app>atus1 photographic equipm5t1 map bo>ds1 etc41 z well z ! ammunition = ! gun4 ,! pilot's comp>tm5t conta9s ! navigat+ in/rum5ts & controls4 99,armam5t994 ,at ! beg9n+ ( ! w> ne>ly all ( ! ,fr5* two seat]s 7 ( ! pu%] type1 ?is arrangem5t1 ( c\rse1 result$ 9 almo/ a completely dead angle ( fire 9 ! re>1 & a front horizontal angle t 0 practically re/rict$ to #afj degrees4 ,ow+ to ! =w>d position ( ! gun ! v]tical angle 0 q good1 #bcj degrees or ev5 bett]4 ,9 ! tractor two seat]1 ) a s+le movable gun m\nt$ ,en b>bette at ! re>1 ! horizontal angle is ab\t #ahj degrees1 b ! v]tical angle is less ?an ) ! pu%] type4 ,:5 ! re> gun is supplem5t$ ) a front rigidly m\nt$ gun1 !re is "s protection at ! front1 b ! rigid gun is f> f be+ z effective z ! pivot$ re> gun4 ,! front gun ( c\rse fires ?r\gh ! propell]4 ,?is armam5t is us$ by ! ,g]man ma*9es ,aviatic1 ,rumpl]1 ,albatros1 & ,l4 ,v4 ,g4 ,! =w>d rigid gun is usually ( ! infantry type1 :ile ! movable re> gun is light]4 ,! latt] is f$ by drums1 or roll$ b&s on spools1 s t reload+ c be p]=m$ 9 ! w9d /ream4 ,) ! two seat] type us$ 9 reconnaissance1 artill]y spott+1 or photography1 ! p[] is g5]ally 9 ! neighborhood ( #bbj-bfj horsep[]1 & ! spe$ v>ies f #he to #ajj miles p] h\r4 ,! area is approximately #djj to #dhj squ>e feet4 ,a s+le eng9e is g5]ally us$4 99,g5]al ,dim5sions & ,spe$s994 ,reconnaissance ma*9es ( v>i\s types & makes are li/$ 9 ! foll[+ table4 ,a pu%] is indicat$ by 7,p7 & a tractor by 7,t74 ,! ,g]man a]oplanes 7,g71 & ! ,alli$ a]oplanes 7,a71 are bo? li/$ = comp>ison3 ,x w be not$ t sev]al types ( ma*9es h be5 made by ! same firms1 & t 9 "s cases ! same ma*9es h diff]5t p[] plants4 ,! ,albatros ,c-,,iii has be5 furni%$ ) bo? ! #agj & #bbj ,m]c$es motor4 ,! ,ago biplane has a tap]+ w+1 & ! *ord wid? 7997 giv5 is tak5 at ! body4 ,:ile v rec5t ma*9es _c be describ$1 because ( c]ta9 re/rictions1 ! horsep[] ( ! late/ two seat]s w av]age ab\t #bdj horsep[]4 ,if ! dates & p[] items are not$1 x w be se5 t ! ma*9es us$ 9 #aiag h mu* l>g] motors ?an ^? built 9 #aiaf4 ,! weight p] squ>e foot ( surface w av]age ab\t #f4e p\nds4 ,! load+ p] horsep[] r>ely exce$s #ag4j p\nds4 99,bomb+ ,type ,a]oplanes994 ,^! l>ge a]oplanes are fitt$ ) ei!r two or ?ree indep5d5t p[] plants4 ,! ,g]man bomb]s are repres5t$ by ! ,go?a1 ,a4 ,e4 ,g41 ,fri$ri*%af51 & ,rumpl] ,g1 :ile ! ,alli$ bomb]s are ! ,caproni1 ,h&ley-,page1 ,f>man1 ,vois91 etc4 ,! spe$ is ab\t t ( ! reconnaissance type1 & w seat ?ree or m m54 ,! motors av]age #ejj #efj horsep[] p] p[] plant1 & ! w+ area is usually well ov] #a1jjj squ>e feet4 ,! small two seat]s are g5]ally equipp$ ) two pivot$ ma*9e guns1 :ile ! ?ree seat]s h a ?ird ma*9e gun arrang$ s t x c be l[]$ & fir$ ?r\gh a trap door 9 ! bottom ( ! body4 ,def5se may ?us be _h f ! re>1 or bel[4 ,9 "s ( ! pu%] types1 a rapid fire gun ( comp>atively heavy calib] is m\nt$ at ! front ( ! body 9 place ( ! usual ma*9e gun4 ,?is is usually ! case ) ! sea planes us$ = subm>9e *as+4 ,9 addition to bomb+ op]ations1 ^! l>ge ma*9es are also us$ = ! protection ( spott+ a]oplanes1 or = ! direct protection ( ! l9es aga9/ l& attacks4 ,^! heavily arm$ bomb]s are v difficult to attack1 ev5 = ! small] & m agile ,*as]s1 z !y c fire f bel[ z well z f ! front1 top1 or sides4 ,9 ! bomb]s :i* h only a s+le gun 9 ! re>1 ! gunn] is work+ at a disadvantage if 8 adv]s>y =ces him to cont9ually raise & l[] 8 gun f ! top ( ! body to ! l[] trap door4 ,?is is v tir+ to ! re> gunn]1 & if ! *as]'s tactics are c>ri$ out = a suffici5t l5g? ( "t1 x c we> out ! gunn] by cont9ually ris+ & dropp+ at ! tail ( ! bomb+ plane4 ,9 reg>d to ! front gun1 ! tw9 motor type (f]s _m ( ! advantages ( ! pu%]1 & z a :ole1 ! tw9 arrangem5t w ne>ly d\ble ! field ( fire ( ei!r ! tractor or pu%]4 ,! bomb+ planes mu/ h a v l>ge radius ( action1 p>ticul>ly ^? t are us$ 9 night bomb+ op]ations4 ,! ,go?as 9 bomb+ ,london fly sev]al hundr$ miles f _! base1 & rec5tly a ,h&ley-,page bomb+ plane flew f ,london to ,con/ant9ople1 ,turkey1 mak+ only a few /ops on ! way4 ,/>t+ out f ,h5don1 ,engl&1 ! ,h&ley-,page ma*9e flew to ,p>is1 d[n ! ,rhone valley to ,lyons & ,m>seilles1 & !n to ,pisa1 & ,rome 7,italy71 :]e !y l&$4 ,f ,rome ! ma*9e pass$ ov] ,naples1 ov] ,oranto & !n ov] ! ,albanian ,alps to ! base at ,salonica4 ,mak+ prep>ations at ?is base !y flew ! f9al /age ( ! trip to ,con/ant9ople1 a di/ance ( #bej miles ov] ho/ile c\ntry4 ,! bomb+ ( ! ,turki% capital 0 done at night aft] a flight ( #b #a_/b h\rs f ,salonica4 ,:5 ov] ! sea ( ,m>mora1 ! %ip ,goeb5 0 bomb$1 & 9 addition a hit 0 scor$ on ! two subm>9es ly+ at h] side4 ,f\r bombs /ruck ! ,goeb5 directly1 f an altitude ( #hjj feet4 ,two m bombs 7 dropp$ on ! ,g]man %ip1 ,g5]al1 :i* 0 ! headqu>t]s ( ! ,g]man /aff4 ,f9ally1 aft] #cj m9utes ov] ! city ( ,con/ant9ople1 ! ,turki% ,w> ,(fice 0 ! recipi5t ( two m bombs4 ,9 ! words ( ! ,turki% communiqu ?is ,0 n entirely de/roy$4 ,on its return to ,salonica x 0 f\nd t ! ma*9e _h be5 /ruck by #bf %rapnel bullets4 ,?is disabl$ "o ( ! p[] plants s t ! great] "p ( ! return j\rney 0 made on a s+le motor4 ,f ,london to ,salonica five m5 7 c>ri$4 ,9 addition 0 _! luggage1 b$d+1 two tool boxes1 sp>e p>ts equival5t 9 weight to "o eng9e1 & two #aa'-f sp>e propell]s4 ,complete1 ! ma*9e weigh$ ov] #f tons1 ) a useful load ( ab\t #f1jjj p\nds4 ,9 cross+ ! ,albanian ,alps ! ma*9e frequ5tly 0 at an altitude ( #aj1jjj feet4 ,! p[] plant consi/$ ( two #bge horsep[] ,rolls-,royce motors1 & ev5 at ?is high altitude1 & ) ! heavy load+1 no tr\ble 0 exp]i5c$4 ,dur+ ! bomb+1 only ?ree m5 7 c>ri$1 ! rema9d] ( ! useful weight be+ made up ( bombs & o!r ammunition4 ,:ile ?is record w probably be beat5 be=e ?is book goes to press1 x w at lea/ give an idea z to ! requirem5ts & capabilities ( ! bomb+ type a]oplane4 99,milit>y ,tra9+ ,ma*9es994 ,! milit>y tra9+ ma*9es us$ 9 ! ,unit$ ,/ates are g5]ally ( ! two seat] tractor type1 simil> 9 ext]nal appe>ance to ! reconnaissance type ma*9es already describ$4 ,!y are l[ p[]$1 #ij to #abe horsep[]1 & w h an av]age span ( #dj'-j4 ,! controls are 9 duplicate s t ! /ud5t's controls move 9 unison ) ! in/ructor's4 ,,*apt] ,,iii4 ,,elem5t>y ,,a]odynamics 99,def9ition994 ,a]odynamics treats ( ! =ces produc$ by air 9 motion1 & is ! basic subject 9 ! /udy ( ! a]oplane4 ,x is ! purpose ( ?is *apt] to describe 9 detail ! action ( ! w+ 9 flight1 & ! a]odynamic behavior ( ! o!r bodies t ent] into ! con/ruction ( ! a]oplane4 ,at pres5t1 a]odynamic data is almo/ entirely bas$ on exp]im5tal inve/igations4 ,! motions & reactions produc$ by di/urb$ air are s complex & involv$ t no complete ma!matical !ory has yet be5 advanc$ t p]mits ( direct calculation4 99,prop]ties ( ,air994 ,air be+ a mat]ial sub/ance1 possesses ! prop]ties ( volume1 weight1 viscosity & compressibility4 ,x is a me*anical mixture ( ! two elem5t>y gases1 oxyg5 & nitrog51 9 ! proportion ( #bc p] c5t ( oxyg5 to #gg p] c5t ( nitrog54 ,x is ! oxyg5 elem5t t produces combu/ion1 :ile ! nitrog5 is in]t & does n readily ent] into comb9ation ) o!r elem5ts1 its evid5t function be+ to act z a dilutant = ! en]getic oxyg54 ,9 combu/ion1 ! oxyg5 ent]s into a *emical comb9ation ) ! fuel :ile ! nitrog5 passes (f ) ! products ( combu/ion un*ang$4 ,air is consid]$ z a fluid s9ce x is capable ( fl[+ l wat]1 b unlike wat]1 x is highly compressible4 ,ow+ to ! diff]5ce betwe5 air & wat] 9 reg>d to compressibility1 !y d n foll[ exactly ! same laws1 b at ord9>y flight spe$s & 9 ! op5 air1 ! v>iations 9 ! pressure are s slight z to cause little diff]5ce 9 ! d5sity4 ,h5ce = 99flight alone991 air may be consid]$ z incompressible4 ,x %\ld be not$ t a compressible fluid is *ang$ 9 d5sity by v>iations 9 ! pressure1 t is1 by apply+ pressure ! weight ( a cubic foot ( a compressible fluid is great] ?an ! same fluid "u a light] pressure4 ,?is is an important consid]ation s9ce ! d5sity ( ! air greatly affects ! =ces t set x 9 motion1 & = ?is reason ! d5sity 7weight p] cubic foot7 is always specifi$ 9 a te/4 ,e exi/+ fluid resi/s ! motion ( a body1 ! opposition to ! motion be+ commonly kn[n z resi/ance4 ,?is is due to ! cohesion betwe5 ! fluid p>ticles & ! resi/ance is ! actual =ce requir$ to break !m ap>t & make room = ! mov+ body4 ,fluids exhibit+ resi/ance are said to h viscosity4 ,9 e>ly a]odynamic rese>*es1 & 9 ! /udy ( hydrodynamics1 ! ma!matical !ory is bas$ on a p]fect fluid1 t is1 on a !oretical fluid possess+ no viscosity1 & :ile ?is conception is an aid 9 /udy+ ! reactions1 ! actual laboratory results are f> f ! comput$ values4 ,su* !ory w\ld assume t a body c\ld move 9 a fluid )\t enc\nt]+ resi/ance1 :i* 9 practice is1 ( c\rse1 impossible4 ,9 reg>d to viscosity1 x may be not$ t air is highly viscu\s--relatively mu* high] ?an wat]4 ,d5sity = d5sity1 ! viscosity ( air is ab\t #ad times t ( wat]1 & consequ5tly ! effects ( viscosity 9 air are ( ! utmo/ importance 9 ! calculation ( resi/ance ( mov+ p>ts4 ,atmosph]ic air at sea level is ab\t #a_/hjj ( ! d5sity ( wat]4 ,its d5sity v>ies ) ! altitude & ) v>i\s atmosph]ic conditions1 & = ?is reason ! d5sity is usually specifi$ at sea level z ?is altitude gives a con/ant base ( measurem5t = all p>ts ( ! _w4 ,z ! d5sity is also affect$ by *anges 9 temp]ature1 a /&>d temp]ature is also specifi$4 ,exp]im5tal results1 :atev] ! pressure & temp]ature at :i* !y 7 made1 are r$uc$ to ! correspond+ values at /&>d temp]ature & at ! normal sea level pressure1 9 ord] t ^! results may be readily comp>able ) o!r data4 ,! normal 7av]age7 pressure at sea level is #ad4g p\nds p] squ>e in*1 or #b1aai p\nds p] squ>e foot at a temp]ature ( #fj ,fahr5heit4 ,at ?is temp]ature #a p\nd ( air occupies a volume ( #ac4ada cubic feet1 :ile at #j ,f4 ! volume %r9ks to #aa4eh cubic feet1 ! correspond+ d5sities be+ #j4jgfaj & #j4jhfcc p\nds p] cubic foot1 respectively4 ,?is ref]s to dry air only z ! pres5ce ( wat] vapor makes a *ange 9 ! d5sity4 ,) a r$uction 9 temp]ature ! pressure increases ) ! d5sity increase s t ! effect ( heat is tw(old 9 its effect4 ,) a con/ant temp]ature1 ! pressure & d5sity bo? decrease z ! altitude increases1 a d5sity at sea level ( #j4jgfaj p\nds p] cubic foot is r$uc$ to #j4jceg p\nds p] cubic foot at an altitude ( #bj1jjj feet4 ,dur+ ?is increase 9 altitude1 ! pressure drops f #ad4g p\nds p] squ>e in* to #f4hg p\nds p] squ>e in*4 ,?is v>iation1 ( c\rse1 greatly affects ! p]=mance ( a]oplanes fly+ at diff]5t altitudes1 & /ill m affects ! p]=mance ( ! motor1 s9ce ! latt] _c take 9 z mu* fuel p] /roke at high altitudes z at l[1 & z a result ! p[] is dim9i%$ z we ga9 9 altitude4 ,! foll[+ table gives ! p[] v>iations at diff]5t heights above sea level4 ,?is air table also gives ! prop]ties ( air ?r\gh ! usual range ( flight altitudes4 ,! pressures correspond+ to ! altitudes are giv5 bo? 9 p\nds p] squ>e in* & 9 in*es ( m]cury s t b>omet] & pressure read+s c be comp>$4 ,9 ! f\r? column is ! p]c5tage ( ! horsep[] available at diff]5t altitudes1 ! horsep[] at sea level be+ tak5 z unity4 ,= example1 if an eng9e develops #ajj horsep[] at sea level1 x w develop #ajj #j4ffff horsep[] at an altitude ( #aj1jjj feet above sea level4 ,! b>ometric pressure 9 p\nds p] squ>e in* c be obta9$ by multiply+ ! pressure 9 in*es ( m]cury by ! factor #j4dije1 ?is be+ ! weight ( a m]cury column #a in* high4 ,illu/ration3 ,,note4-,d5sities m>k$ 99 are int]polat$ f a graph1 b are close en\gh = all ord9>y purposes4 ,9 a]odynamic laboratory reports1 ! /&>d d5sity ( air is #j4jgfjh p\nds p] cubic foot at sea level1 ! temp]ature be+ #ae degrees ,c5tigrade 7#ei degrees ,fahr5heit74 ,?is /&>d d5sity w be assum$ ?r\gh\t ! book1 & h5ce = any o!r altitude or d5sity ! correspond+ corrections mu/ be made4 ,ow+ to ! fact t ! temp]ature decreases z we ga9 altitude1 fur!r corrections mu/ be made 9 ! tabul> values1 b z ! *anges are r difficult to make & are relatively small we w n take ! matt] up at ?is po9t4 ,illu/ration3 ,fig4 #a4 ,air ,fl[ ,ab\t a ,flat ,normal ,plate4 ,pressure ,zone at ,front & 44 ,turbul5t ,zone at ,re> 7,h74 ,arr[s ,%[ ,direction ,o ,,ow4 99,air ,pressure on ,normal ,flat ,plates994 ,:5 a flat plate or plane is held at "r angles or normal to an air /ream1 x ob/ructs ! fl[ & a =ce is produc$ t t5ds to move x ) ! /ream4 ,! /ream divides1z %[n 9 ,fig4 #a & passes all ar\nd ! edges ( ! plate 7,p-,r71 ! /ream reunit+ at a po9t 7,m7 f> 9 ! re>4 ,assum+ ! air fl[ f left to "r1 z 9 ! figure1 x w be not$ t ! re> ( ! plate at 7,h7 is "u a slight vacuum1 & t x is fill$ ) a complicat$ :irl+ mass ( air4 ,! g5]al tr5d ( ! eddy pa?s are indicat$ by ! arr[s4 ,at ! front :]e ! air curr5t fir/ /rikes ! plate !re is a consid]able pressure due to ! impact ( ! air p>ticles4 ,9 ! figure1 pressure above ! atmosph]ic is indicat$ by 9999991 :ile ! vacu\s space at ! re> is indicat$ by f9e dots4 ,z ! pressure 9 front1 & ! vacuum 9 ! re>1 bo? t5d to move ! surface to ! "r 9 ! direction ( ! air /ream1 ! total =ce t5d+ to move ! plate w be ! diff]5ce ( pressure on ! front & re> faces multipli$ by ! area ( ! plate4 ,?us if ,f is ! =ce due to ! impact pressure at ! front1 & ,g is ! =ce due to ! vacuum at ! re>1 !n ! total resi/ance 7,d7 or ,drag is ! sum ( ! two =ces4 ,contr>y to ! common op9ion1 ! vacu\s "p ( ! drag is by f> ! great]1 say 9 ! neighborhood ( f #fj to #ge p] c5t ( ! total4 ,:5 a body exp]i5ces pressure due to ! break+ up ( an air /ream1 z 9 ! pres5t case1 ! pressure is said to be due to turbul5ce1 & ! body is said to produce turbul5t fl[4 ,?is is to di/+ui% ! =ces due to impact & suction1 f ! =ces due to ! frictional drag produc$ by ! air /ream rubb+ ov] ! surface4 ,=ces due to turbul5t fl[ d n v>y directly z ! velocity ( ! air pa/ ! plate1 b at a mu* high] rate4 ,if ! velocity is d\bl$1 ! plate n only meets ) twice ! volume ( air1 b x also meets x twice z fa/4 ,! total effect is f\r times z great z 9 ! fir/ place4 ,! =ces due to turbul5t fl[ !re=e v>y z ! squ>e ( ! velocity1 & ! pressure increases v rapidly ) a small increase 9 ! velocity4 ,! =ce ex]t$ on a plate also increases directly ) ! area1 & to a less] ext5t ! drag is also affect$ by ! %ape & proportions4 ,express$ z a =mula1 ! total resi/ance 7,d7 becomes3 ,d ,,kav1 :]e ,k co-effici5t ( resi/ance det]m9$ by exp]im5t1 ,a area ( plate 9 squ>e feet1 & ,v velocity 9 miles p] h\r4 ,! value ( ,k takes ! %ape & proportion ( ! plate into consid]ation1 & also ! air d5sity4 99,example994 ,if ! area ( a flat plate is #f squ>e feet1 ! co-effici5t ,k #j4jjc1 & ! velocity is #fj miles p] h\r1 :at is ! drag ( ! plate 9 p\nds8 99,solution994 ,d ,,kav #j4jjc #f 7#fj ,x #fj7 #fd4hj p\nds drag4 ,= a squ>e flat plate1 ! co-effici5t ,k c be tak5 z #j4jjc4 99,aspect ,ratio994 ,! aspect ratio ( a plate is ! ratio ( ! l5g? to ! wid?4 ,?us1 ) an aspect ratio ( #b4j1 we und]/& t ! plate is twice z long z x is wide4 ,! ratio ( ! l5g? to ! wid? has a v consid]able influ5ce ( ! resi/ance or drag1 ?is increas+ z ! ratio is made great]4 ,if ! resi/ance ( a squ>e plate is tak5 z #a4jj1 ! resi/ance ( a plate ) an aspect ratio ( #bj w be ab\t #a4cd times z great4 ,! foll[+ table w give ! effects ( aspect ratio on ! resi/ance ( a flat plane4 ,,effects ,,( ,,aspect ,,ratio ,,on ,,flat ,,plates4 ,aspect ,ratio4 ,resi/ance ,k z a ,multiple ( a ,squ>e ,l5g?_/,wid? ,plate4 #a4jj 7squ>e7 #a4jj #a4ej #a4jd #b4jj #a4je #c4jj #a4jg #d4jj #a4jh #e4jj #a4ji #f4jj #a4aj #g4jj #a4ab #i4jj #a4ad #aj4jj #a4ae #ae4jj #a4bf #bj4jj #a4cd #cj4jj #a4dj ,to conv]t ! values ( a squ>e plate into a flat plate ( giv5 aspect ratio1 multiply ! resi/ance ( ! squ>e plate by ! factor "u ! ,k head+4 ,= example3 ,! resi/ance ( a c]ta9 squ>e plate is #bj p\nds1 f9d ! resi/ance ( a plate ( ! same area1 b ) an aspect ratio ( #ae4 99,solution994 ,! factor = a ratio ( #ae w be f\nd to be #a4bf1 h5ce ! resi/ance ( ! requir$ plate w be #bj #a4bfbe4b p\nds4 ,illu/ration3 ,fig4 #b4 ,air ,fl[ ,ab\t a ,/reaml9e ,body ,%[+ an ,almo/ ,complete ,abs5ce ( ,turbul5ce ,except at ! ,extreme ,re> ,edge4 ,resi/ance ,is ,pr9cipally ,due to ,sk9 ,friction4 99,/reaml9e ,=ms994 ,:5 a body is ( su* =m t x does n cause turbul5ce :5 mov$ ?r\gh ! air1 ! drag is entirely due to sk9 friction4 ,su* a body is kn[n z a /reaml9e =m & approximations are us$ = ! expos$ /ructural p>ts ( a]oplanes 9 ord] to r$uce ! resi/ance4 ,/reaml9e bodies are fi%like or torp$o-%ap$1 z %[n by ,fig4 #b1 & x w be not$ t ! air /ream hangs closely to ! outl9e ?r\gh ne>ly its entire l5g?4 ,! drag is !re=e entirely due to ! friction ( ! air on ! sides ( ! body s9ce !re is no turbul5ce or discont9uity4 ,9 practical bodies x is impossible to prev5t ! small turbul5ce 7,i71 b 9 well-design$ =ms its effect is almo/ negligible4 ,9 poor attempts at /reaml9e =m1 ! fl[ discont9ues its adh]5ce to ! body at a po9t ne> ! tail4 ,! poor] ! /reaml9e1 & ! high] ! resi/ance1 ! soon] ! /ream />ts to break away f ! body & cause a turbul5t region4 ,! resi/ance n[ becomes p>tly turbul5t & p>tly frictional1 ) ! resi/ance increas+ rapidly z ! p]c5tage ( ! turbul5t region is increas$4 ,! fact t ! resi/ance is due to two factors1 makes ! resi/ance ( an approximate /reaml9e body v difficult to calculate1 z ! frictional drag & ! turbul5t drag d n increase at ! same rate = diff]5t spe$s4 ,! drag due to turbul5ce v>ies z ,v squ>$ :ile ! frictional resi/ance only v>ies at ! rate ( ,v to ! #a4hf? p[]1 h5ce ! drag due to turbul5ce increases mu* fa/] ) ! velocity ?an ! frictional compon5t4 ,if we c\ld =etell ! p]c5tage ( friction1 x w\ld be fairly easy to calculate ! total effect1 b ?is p]c5tage is exactly :at we d n "k4 ,! only sure me?od is to take ! results ( a full size te/4 ,fig4 #b gives ! approximate section ?r\gh a /reaml9e /rut su* z us$ 9 ! int]plane brac+ ( a biplane4 ,! l5g? is 7,l7 & ! wid? is 7d71 ! latt] be+ measur$ at ! wide/ po9t4 ,! relation ( ! l5g? to ! wid? is kn[n z ! f95ess ratio & 9 int]plane /ruts ?is may v>y f #b4e to #d4e1 t is1 ! l5g? ( ! section ranges f #b4e to #d4e times ! wid?4 ,! ideal /reaml9e =m has a ratio ( f #e4 to #e4ge4 ,su* l>ge ratios are difficult to obta9 ) economy on practical /ruts z ! small wid? w\ld result 9 a weak /rut unless ! weight 7 unduly increas$4 ,int]plane /ruts rea* a maximum f95ess ratio at ab\t #c4e to #d4e4 ,fig4 #c %[s ! result ( a small f95ess ratio1 ! %ort1 /ubby body caus+ ! /ream to break away ne> ! front & =m a l>ge turbul5t region 9 ! re>4 ,an approximate =mula %[+ ! relation ( f95ess ratio & resi/ance 7curvature equal7 0 develop$ by ,a4 ,e4 ,b]riman1 & publi%$ 9 ,flight ,nov4 #ab1 #aiae4 ,let ,d resi/ance ( a flat plate at a giv5 spe$1 & ,r resi/ance ( a /rut at ! same spe$ & ( ! same area1 !n ! relation betwe5 ! resi/ance ( ! flat plate1 & ! /rut w be express$ by ! =mula ,r_/,d#d,l_/#cjj;d1 :]e ,l l5g? ( section & d wid? z 9 ,fig4 #b4 ,?is c be transpos$ = conv5i5ce1 by assum+ ! drag ( a flat plate z ,d #j4jjc;,,av1 :]e ,a area 9 squ>e feet1 & ,v velocity 9 miles p] h\r4 ,! ratio ( ! /rut resi/ance to ! flat plate resi/ance1 giv5 by ,b]riman's =mula1 c n[ be multipli$ by ! flat plate resi/ance1 or /rut resi/ance ,r #j4jjc;,,av ,x #d,l_/#cjj;d4 #j4jab,,lav_/#cjj;d4 ,x %\ld be und]/ood t ! area m5tion$ above is ! greate/ area pres5t$ to ! w9d 9 squ>e feet1 & h5ce is equal to ! l5g? ( ! /rut 7n section7 multipli$ by ! wid? 7d74 ,illu/ration3 ,fig4 #c4 ,imp]fect ,/reaml9e ,body ) a ,consid]able ,turbul5ce ,due to ! ,%ort1 ,/ubby ,=m4 ,fig4 #d ,%[s ! ,fl[ ,ab\t a ,circul> ,rod or ,cyl9d]4 ,assum+ ! l5g? 7,l7 ( ! section z #g4e in*es1 & ! wid? 7d7 z "o in*1 ! f95ess ratio w be #g4e4 ,us+ ! ,b]riman =mula 9 its orig9al =m1 ! relative resi/ance ( ! /rut & flat plate ( same area w be f\nd z ,r_/,d#d,l_/#cjjj #j4a1 t is1 ! resi/ance ( a /reaml9e =m /rut ( above f95ess ratio w be ab\t #j4a ( a flat plate ( ! same area4 ,x %\ld be und]/ood t ?is is only an approximate =mula s9ce ev5 /ruts ( ! same f95ess v>y among !mselves accord+ to ! outl9e4 ,results publi%$ by ! ,national ,physical ,laboratory %[ /reaml9e sections giv+ #j4jg ( ! resi/ance ( a flat plate ( ! same area1 ) f95ess ratio #f4e4 ,9 ,fig4 #d ! effects ( fl[ ab\t a circul> rod is %[n1 a case :]e ! f95ess ratio is #a4 ,! /ream foll[s ! body ?r\gh less ?an "o-half ( its circumf]5ce1 & ! turbul5t region is v l>ge2 almo/ z great z ) ! flat plate4 ,a circul> rod is f> f be+ ev5 an approa* to a p]fect =m4 ,9 all ! cases %[n1 ,figs4 #a-b-c-d1 x w be notic$ t ! air is affect$ = a consid]able di/ance 9 front ( ! plane1 z x rises to pass ov] ! ob/ruction be=e x actually rea*es x4 ,! front compression may be p]ceptible = #f diamet]s ( ! object4 ,f ! exam9ation ( sev]al good l[-resi/ance /reaml9e =ms x seems t ! be/ results are obta9$ ) ! blunt nose =w>d & ! ?9 end aft4 ,! be/ position = ! po9t ( greate/ ?ickness lies f #j4be to #j4cc p] c5t ( ! l5g? f ! front end4 ,f ! ?icke/ "p x tap]s out gradually to no?+ at ! re> end4 ,t portion to ! re> ( ! maximum wid? is ! mo/ important f ! /&po9t ( resi/ance1 = any irregul>ity 9 ?is region causes ! /ream to break away into a turbul5t space4 ,f exp]im5ts x has be5 f\nd t z mu* z "o-half ( ! ent]+ nose c be cut away )\t mat]ially increas+ ! resi/ance4 ,! cut-(f nose may be left flat1 & /ill ! loss is only 9 ! neighborhood ( #e p] c5t4 99,resi/ance ,calculations 7,turbul5cy7994 ,9 any plate or body :]e ! resi/ance is pr9cipally due to turbul5t action1 z 9 ! flat plate1 sph]e1 cone1 etc41 ! resi/ance c be comput$ f ! =mula ,r ,,kav1 :]e ,r is ! resi/ance 9 p\nds & ,k1 ,a1 & ,v are z be=e4 ,! resi/ance co-effici5t 7,k7 dep5ds ^u ! %ape ( ! object "u /&>d air conditions1 & diff]s greatly ) flat plates1 cones1 sph]e1 etc4 ,! area 7,a7 is ! area pres5t$ to ! w9d1 or is ! greate/ area t faces ! w9d1 & is tak5 at "r angles to its direction4 ,! foll[+ table gives ! value ( ,k = ! m common =ms ( objects4 ,see ,figs4 #d to #ab1 inclusive3 ,!re are almo/ an inf9ite numb] ( diff]5t =ms1 b = ! pres5t ! above examples w fill our purpose4 ,z an example 9 %[+ h[ greatly ! =m ( an object influ5ces its resi/ance1 we w "w out ! resi/ance ( a flat plate & a sph]ical end$ cone1 bo? hav+ ! same pres5t$ diamet]4 ,! cone is plac$ s t ! sph]ical end w face ! air /ream4 ,! area ,a ( bo? objects w be3 #j4ghed #b #b #c4adaf squ>e feet4 ,) an assum$ w9d velocity ( #ajj miles p] h\r1 ! resi/ance ( ! circul> flat disc w be3 ,r ,,kav#jjjbhb #c4adaf 7#ajjajj7 #hg4if lbs4 ,= ! cone1 ,r ,,kav#j4jjjbbb #c4adaf 7#ajj #ajj7 #f4ig lbs4 ,f ?is calculation x w be se5 t x is advisable to surr\nd ! object ) a sph]ical cone %ap$ body r ?an to pres5t ! flat surface to ! w9d4 ,9 ! above table ! value ( ,k is giv5 = two positions ( ! sph]ical bas$ cone1 ! fir/ is ) ! apex t[>d ! w9d1 & ! second condition gives ! value ) ! base to ! w9d4 ,) ! blunt end =w>d1 ! resi/ance is ab\t "o-half t :5 ! po9t$ apex ent]s ! air /ream4 ,?is is due to ! tap] clos+ up ! /ream )\t caus+ turbul5ce4 ,illu/ration3 ,figs4 #d;a-#e-f-g-h-i-aj-aa-ab4 ,! ,values ( ! ,resi/ance ,co-effici5t ,k = ,diff]5t ,=ms & ,positions ( ,solid ,objects4 ,arr[s ,indicate ! ,direction ( ! ,relative ,w9d4 7,eiffel47 ,) ! apex =w>d !re is no?+ to fill up ! vacu\s space :5 ! air passes ov] ! l>ge diamet] ( ! base z ! curve ( ! sph]ical end is too %ort to accompli% mu* 9 ?is direction4 99,sk9 ,friction994 ,! air 9 rubb+ ov] a surface exp]i5ces a frictional resi/ance simil> to wat]4 ,at ! pres5t "t ! accept$ exp]im5ts are ^? ( ,dr4 ,zahm b ^! are /ill 9 "s "q z to accuracy4 ,x 0 f\nd 9 ^! exp]im5ts t !re 0 practically no diff]5ce caus$ by ! mat]ial ( ! surfaces1 z long z !y 7 equally smoo?4 ,l95 or cotton gave ! same results z smoo? wood or z9c z long z !re 0 no nap or l9t ^u ! surface4 ,) a fuzzy surface ! friction increas$ rapidly4 ,?is is und\bt$ly due to a m9ute turbul5ce caus$ by ! unev5 surface1 & h5ce ! increase 0 n purely frictional1 b also due to turbul5ce4 ,9 ! te/s1 ! air curr5t 0 l$ p>allel to ! surface 9 su* a way t only ! friction c\ld move ! surface4 ,! surface 0 freely susp5d$1 & z ! w9d mov$ x edgewise1 ! movem5t 0 measur$ by a %>p po9t]4 ,end %ields prev5t$ impact ( ! air on ! end ( ! te/ piece s t !re 0 no error f ?is s\rce4 ,! complete =mula giv5 by ,dr4 ,zahm is r complicat$ = ord9>y use1 especially = ^? n us$ to ma!matical computations4 ,if ,rf resi/ance due to friction on "o side ( surface1 ,l l5g? 9 direction ( w9d 9 feet1 b wid? ( surface 9 feet1 & ,v velocity 9 feet p] second1 !n ,rf #j4jjjjjggh,l4,v4b4 ,x w be not$ t ! resi/ance increases at a l[] rate ?an ! velocity squ>$1 & at a less rate ?an ! area4 ,t is to say1 t d\bl+ ! area w n d\ble ! resi/ance1 b w be less ?an twice ! am\nt4 ,giv+ ! =mula 9 t]ms ( area & miles p] h\r units1 we h3 ,rf #j4jjjjafg;,a4,v44 ,:]e ,a area 9 squ>e feet & ,v miles p] h\r4 ,! area is = "o side ( ! surface only4 ,a r\gh approximation to ,zahm's equation has be5 propos$ by a writ] 9 ,flight1 ! int5tion be+ to avoid ! complicat$ =mula & yet come close en\gh to ! orig9al = practical purposes4 ,! latt] =mula reads3 ,rf #j4jjjjji,v :]e ,rf & ,v are z above4 ,up to #dj miles p] h\r ! results are v close to ,zahm's =mula1 & are fairly close f #fj to #ij miles p] h\r4 ,?is approximation is only ju/ifi$ :5 ! l5g? 9 ! direction ( ! w9d is ne>ly equal to ! l5g?4 ,if ! l5g? is mu* great]1 !re is a s]i\s error introduc$4 ,?is =mula is appli$ to surfaces p>allel to ! w9d su* z ! sides ( ! body1 rudd]1 /abiliz]1 & elevator surfaces 7:5 9 neutral74 ,a second important feature ( ! friction =mula is t x illu/rates ! law ( similitude or ! results ( a *ange 9 scale & velocity1 h5ce x outl9es :at we mu/ expect :5 we compute a full size a]oplane f ! results ( a model te/4 99,! ,incl9$ ,plane994 ,:5 a flat plate is incl9$ ) ! w9d1 ! resi/ance or drag w be brok5 up into two compon5ts1 "o at "r angles to ! air /ream1 & "o p>allel to x4 ,if ! plate is prop]ly incl9$1 ! "r angl$ compon5t c be utiliz$ 9 obta9+ lift z ) an a]oplane w+4 ,?is is %[n 9 ,fig4 #ac :]e ,l is ! v]tical lift =ce at "r angles to ! air /ream & ,d is ! horizontal drag act+ 9 ! direction ( ! w9d4 ,z 9 ! case ( ! plate plac$ normal to ! w9d1 !re is pressure at ! front ( ! plate & a p>tial vacuum beh9d4 ,! resultant =ce w be det]m9$ by ! diff]5ce 9 pressure betwe5 ! front & ! back ( ! plate4 ,! =ces w v>y z ,v s9ce ! reaction is caus$ by turbul5t fl[4 ,bo? ! lift & drag w v>y ) ! angle made ) ! /ream1 & !re w be a diff]5t value = ! co-effici5t ,k = ea* *ange 9 ! angle4 ,! angle made ) ! air /ream is kn[n z ! ,angle ( incid5ce or ! ,angle ( attack4 ,! *ange ( drag & lift does n v>y at a regul> rate ) ! angle4 ,illu/ration3 ,fig4 #ac4 ,fl[ ,ab\t1 ,incl9$ ,plane & ,=ces ,produc$ by ,/ream4 ,fig4 #ad4 ,normal ,plane ) ,c4,p4 at c5t] ( ,plate4 ,fig4 #ae44 ,c4,p4 ,moves ,t[>d ,ent]+ ,edge ,:5 ,plate ,is ,incl9$ to ,w9d4 ,a l9e ,,or is ! resultant ( ! lift & drag =ces ,l & ,d1 ?is resultant be+ ! =ce necess>y to balance ! two =ces ,l-,d4 ,x is on ! po9t ( application ,o t ! plate balances1 & ?is po9t is sometimes kn[n z ! ,c5t] ( pressure4 ,! c5t] ( pressure is !re=e ! po9t at :i* ! resultant int]sects ! surface ( ! flat plate4 ,! resultant ,,or is approximately at "r angles to ! surface at small incid5t angles1 & ! po9t ,o is ne>] ! front or lead+ edge 7,a7 ( ! plane4 ,! small] ! angle ( incid5ce ! ne>] w ! po9t ,o approa* ! lead+ edge ,a4 ,by draw+ ,,ol to scale1 repres5t+ ! lift1 & ,,od to scale repres5t+ ! drag1 we c f9d ! resultant ,,or by draw+ ,,lr p>allel to ! drag ,,od & ,,dr p>allel to ! lift l9e ,,ol4 ,all l9es drawn ?r\gh ! int]section ( ,,lr & ,,dr w give ! resultant ,,or to scale4 ,all ( ! l9es mu/ be />t$ f ! c5t] ( pressure at ,o4 ,! lea/ resultant w1 ( c\rse1 occur :5 ! plane is p>allel to ! air /ream4 ,! maximum resultant w occur :5 ! angle ( incid5ce is ab\t #dj degrees1 & on a fur!r increase 9 ! angle1 ! value ( ! resultant w gradually decrease4 ,:5 ! plane is p>allel ) ! /ream1 ! resultant is p>allel to ! plate1 b rapidly approa*es a position at "r angles at ab\t an incid5ce ( #f to #aj degrees4 ,beyond #aj degrees incid5ce ! angle ( ! resultant increases pa/ ! normal4 ,! c5t] ( pressure 7,o71 or ! po9t :]e ! resultant =ce int]sects ! plane1 moves =w>d z ! angle ( incid5ce is decreas$ f #ij4 ,:5 at "r angles to ! air curr5t1 ! c5t] ( pressure is exactly 9 ! c5t] ( ! plane z %[n by ,fig4 #ad4 ,9 ?is case ! drag 7,d7 is ! resultant1 & act+ 9 ! c5t]1 exactly balances ! air =ces4 ,9 ,fig4 #ae ! angle ( incid5ce is r$uc$1 consequ5tly ! c5t] ( pressure moves ne>] ! lead+ edge 7,a74 ,z ! angle cont9ues to decrease1 ! ,c4 ,p4 moves /ill fur!r =w>d until x lies directly on ! front edge :5 ! plate becomes p>allel ) ! air /ream4 ,! c5t] ( pressure movem5t is due to ! fact t m & m "w is done by ! front "p ( ! surface z ! angle is decreas$4 ,consequ5tly ! po9t ( support1 or ,c4 ,p41 mu/ move =w>d to come "u ! load4 ,x %\ld be und]/ood t ! plane w balance ab\t ! ,c4 ,p4 if a knife edge be>+ 7 appli$ z at ,r 9 ,fig4 #ae4 99,calculation ( ,incl9$ ,planes994 ,we w n[ consid] ! incl9$ plane z a lift+ surface = an a]oplane1 & make ! elem5t>y calculations = su* purpose4 ,! lift w fir/ be calculat$ = ! support ( ! giv5 load1 at ! giv5 velocity1 & !n ! drag4 ,= sev]al reasons1 t w aft]w>ds be expla9$1 ! flat plate or plane is n us$ = ! ma9 lift+ surfaces1 b ! exp]i5ce ga9$ 9 comput+ ! plate w be ( great assi/ance :5 we />t calculat+ actual w+s4 99,lift & ,drag ,co-effici5ts994 ,! lift compon5t 7,l7 ( ! incl9$ flat plate dep5ds on ! velocity1 area1 aspect ratio & angle ( incid5ce4 ,in/ead ( us+ ! co-effici5t 7,k7 =m]ly us$ = ! total drag1 we w use ! lift co-effici5t ,ky4 ,! =mula = lift n[ becomes3 ,l ,ky,a,v :]e ,a area 9 squ>e feet1 & ,v velocity 9 miles p] h\r4 ,! lift co-effici5t ,ky1 dep5ds ^u ! angle ( incid5ce4 ,! horizontal drag ,d w be calculat$ f ! drag co-effici5t ,kx1 :i* is us$ 9 ! same way z ! co-effici5t ,k 9 ! case ( ! normal plate4 ,! subscript 7x7 is us$ to di/+ui% x f ! lift co-effici5t4 ,bo? ,ky & ,kx mu/ be correct$ = aspect ratio4 ,! drag c be calculat$ f ! =mula3 ,d ,kx,a,v :]e ! lett]s ,a & ,v are ! same z above4 ,= ! calculation ( ! drag1 we w use a new expression--! ,lift-,drag ,ratio--or z m commonly giv51 ,l_/,d4 ,?is %[s ! relation betwe5 ! lift & drag1 s t by kn[+ ! lift & ! ratio = any p>ticul> case1 we c compute ! drag )\t ! necessity ( go+ ?r\gh ! t$i\s calculation ,d ,kx,a,v4 ,! lift-drag ratio = a flat plate v>ies ) ! angle ( incid5ce1 & ! aspect ratio1 & h5ce a sep>ate value mu/ be us$ = e incl9ation & *ange 9 aspect4 ,to obta9 ! drag1 divide ! lift by ! lift-drag ratio4 ,h5ce if ! lift is #abjj p\nds1 & ! ratio equals #f4jj1 ! drag w be3 #abjj_/fbjj p\nds1 or 9 o!r words1 ! lift is #f times ! drag =ce4 ,*ang+ ! angle ( incid5ce ?r\gh angles rang+ f #a degree to #g degrees1 ! lift-drag ratio ( a flat plate w v>y f #a4e to #g4e4 ,:5 ! plane is p>allel to ! w9d /ream & gives no lift1 ! drag is comput$ f ,zahm's sk9 friction =mula4 ,! foll[+ tables give ! values ( ,ky1 ,kx1 ,l_/,d1 & c5t] ( pressure movem5t = flat plates ( v>i\s aspect ratios4 ,! c5t] ( pressure 7,c4 ,p47 = ea* angle is giv5 z a decimal fraction ( its di/ance f ! lead+ edge1 9 t]ms ( ! wid? or ,*ord4 ,illu/ration3 ,fig4 #af4 ,plan ,view ( ,plate ) ,long ,edge to ,w9d4 ,fig4 #ag4 ,plate ) ,n>r[ ,edge to ,w9d1 ,%[+ ,loss 9 ,lift4 #ag;a ,%[s ,effect ( ,rak$ ,tips4 ,fig4 #af %[s ! top view or plan ( a lift+ surface1 ) ! direction ( ! w9d /ream indicat$ by ! arr[s w-w-w w4 ,! long] side or span is indicat$ by ,s1 :ile ! wid? or *ord is ,c4 ,ma9 lift+ surfaces1 or w+s1 h ! long side at "r angles to ! w9d z %[n4 ,:5 9 ?is position1 ! surface is said to be 9 ,pt]ygoid ,aspect1 & :5 ! n>r[ edge is pres5t$ to ! w9d1 ! w+ is 9 ,apt]oid ,aspect4 ,! ^w ,pt]ygoid means ,bird l1 & 0 *os5 = ! condition 9 ,fig4 #af1 z ?is is ! me?od 9 :i* a bird's w+ meets ! air4 ,contr>y to ! case ) true curv$ a]oplane w+s1 flat planes usually give bett] lift 9 apt]oid ?an 9 pt]ygoid aspect at high angles4 ,! aspect ratio w be ! span 7,s7 divid$ by ! *ord 7,c71 or ,aspect ratio ,s_/,c4 ,x w be se5 f ! above t ! lift coeffici5t ,ky increases ) ! aspect ratio1 & t x g5]ally decl9es aft] an angle ( #cj degrees4 ,! c5t] ( pressure moves /eadily back ) an increase 9 angle4 99,example = ,lifts994 ,a c]ta9 flat plane has an area ( #bjj squ>e feet1 & moves at #ej miles p] h\r4 ,! angle ( incid5ce is #aj degrees1 & ! aspect ratio is #f4 ,f9d ! total lift & ! drag 9 p\nds4 ,also ! location ( ! c5t] ( pressure 9 reg>d to ! lead+ edge1 if ! *ord is #e4h feet4 99,solution994 ,"u ! table head$1 ,aspect ,ratio #f we f9d t ,ky at #aj #j4jjagc1 & t ! lift drag ratio is #e4b4 ,! c5t] ( pressure is #j4ccc ( ! *ord f ! front edge4 ,! total lift !n becomes3 ,l ,ky,a,v #j4jjagc x #bjj x 7#ej x #ej7 #hfe p\nds4 ,s9ce ! lift drag ratio is #e4b1 ! drag ,d #hfe_/e4b #aff4c p\nds4 ,! c5t] ( pressure w be locat$ #e4h x #j4ccc #a4d feet f ! lead+ edge4 ,"u ! same conditions1 b ) an aspect ratio ( #c1 ! lift w become3 ,l ,ky,a,v #j4jjad x #bjj x7#ej x #ej7 #gjj p\nds4 ,9 ?is case ! lift drag ratio is #e4a1 s t ! drag w be #acg4h p\nds4 ,ev5 ) ! same area1 ! aspect ratio makes a diff]5ce ( #hfe-gjj #afe p\nds4 ,if we 7 compell$ to c>ry ! orig9al #hfe p\nds ) aspect #c w+1 we w\ld also be compell$ to increase ! area1 angle1 or spe$4 ,if ! spe$ 7 to be kept con/ant1 we w\ld be limit$ to a *ange 9 area or angle4 ,9 ! latt] case x w\ld be pref]able to increase ! area1 s9ce a suffici5t increase 9 ! angle w\ld greatly increase ! drag4 ,x w be not$ t ! lift-drag ratio decreases rapidly ) an increase 9 ! angle4 ,illu/ration3 ,burgess ,seaplane ,sc\t4 99,calculation ( ,area993 ,let u assume t we are conf9$ to ! use ( an aspect ratio ( #f1 a spe$ ( #ej miles p] h\r1 weight #bejj p\nds1 & wi% to obta9 ! area t w give ! mo/ effici5t surface 7,lea/ lift-drag ratio47 ,! equation c be n[ transpos$ s t ! area ,a ,ky,v4 ,on exam9ation ( ! table x w be se5 t ! greate/ lift-drag ratio is #f4d at #e degrees1 & t ! ,ky at ?is angle is #j4jjajc4 ,sub/itut+ ^! values 9 ! equation = area1 we h ,a ,l_/,ky,v #bejj_/jjjajc x 7#ej x #ej7 #iga squ>e feet4 ,illu/ration3 ,w9d ,tunnel at ,wa%+ton ,navy ,y>d 9 ,:i* ! ,air ,circulates ,cont9u\sly ,?r\gh a ,clos$ ,circuit ,,*apt] ,,iv4 ,,exp]im5tal ,,laboratories4 99,te/ ,me?ods 9 ,g5]al994 ,z already expla9$1 ! behavior ( a body 9 an air /ream _c be pr$ict$ ) any c]ta9ty by direct ma!matical calculation1 & = ?is reason1 ea* & e a]odynamic body mu/ be te/$ "u conditions t are z ne>ly simil> to ! actual work+ conditions z possible4 ,prior to ,pr(essor ,langley's fir/ exp]im5ts 9 #ahhg1 me*anical flight ) a heavi] ?an air ma*9e 0 d]id$ z an impossibility1 ev5 by su* sci5ti/s z ,navi]1 ,von ,helmotz1 ,gay-,lussac1 & o!rs1 :o prov$ by ! mo/ intricate calculations t a body l>g] ?an a bird c\ld n be support$ by its own en]gy4 ,su* calculations 71 ( c\rse1 bas$ on a wrong und]/&+ ( air fl[1 & z no exp]im5tal "w _h be5 done up to t "t1 ! fl[ 0 assum$ accord+ to ! individual ta/e & belief ( ! demon/rator4 ,! pres5ce ( a vacuum on ! back ( a plate 0 n und]/ood1 & z ?is contributes full two-?irds ( ! lift1 x is an easy matt] to see :y all ( ! e>ly pr$ictions fell %ort ( ! actual lift+ =ces4 ,to quote "o classic absurdity1 ! sci5ti/ ,navi] prov$ ma!matically t if me*anical flight 7 possible1 !n #ag swall[s w\ld be capable ( develop+ "o horsep[]4 ,9 spite ( ^! disc\rag+ computations1 ,langley proce$$ ) a v c>efully conduct$ s]ies ( exp]im5ts1 fir/ inve/igat+ ! laws ( surface su/5ation on v>i\s =ms ( plates1 & :5 ! data collect$ 0 suffici5t = 8 ne$s1 he />t$ to con/ruct a numb] ( model fly]s ) v>i\s w+ arrangem5ts & a](oil =ms4 ,x 0 ,langley's exp]im5ts ^u a](oils t cle>$ ! way = ! ,wright ,bro!rs1 :o />t$ a fur!r & m complete inve/igation 9 #ahif4 ,exp]im5ts 7 made on ! effect ( curvature1 aspect ratio & angle ( incid5ce1 & ! results obta9$ 9 _! w9d tunnel 7 aft]w>ds appli$ to _! successful full size ma*9e4 ,dur+ #aija to #aijb ! ,wrights inve/igat$ ! prop]ties ( at lea/ #ajj diff]5t a](oil =ms4 ,bo? ,langley's & ,wrights' exp]im5ts 7 ) models1 al?\gh !y 7 made 9 a diff]5t mann]4 ,x 0 9 ?is way t exp]im5tal evid5ce ga9$ prec$5ce ov] !ory4 ,langley's specim5s 7 m\nt$ at ! end ( a revolv+ arm1 s t ) ! arm revolv+1 a relative air /ream ( kn[n velocity c\ld be _h4 ,! a](oil 0 m\nt$ 9 su* a way t ! lift & drag c\ld be measur$4 ,9 ! e>ly exp]im5ts ( ! ,wrights1 ! models 7 plac$ 9 an enclos$ *annel ?r\gh :i* a /ream ( air 0 ma9ta9$ by a fan4 ,! model 0 atta*$ to a balance sy/em s t ! lift & resi/ance c\ld be measur$4 ,?is is :at is n[ kn[n z a w9d tunnel1 & at pres5t is almo/ exclusively us$ 9 model te/s4 ,sev]al inve/igators imm]s$ _! model a](oils 9 runn+ wat] s t ! direction ( fl[ c\ld be visibly obs]v$4 ,:ile ?is latt] me?od is ( great s]vice 9 det]m9+ di/urbances1 /ream l9e fl[1 & g5]al *>act]i/ics1 x is qualitative r ?an quantitative1 & _c be us$ 9 obta9+ accurate num]ical results4 ,a m accurate me?od ( mapp+ out ! direction ( fl[1 eddies1 etc41 is to introduce smoke into ! air /ream4 99,full ,size ,exp]im5ts994 ,! old rule ( ! ?umb me?od ( build+ a full size ma*9e )\t model te/ data or o!r exp]im5tal evid5ce to beg9 ) has se5 its day4 ,x is n only exce$+ly exp5sive1 b is highly dang]\s1 & _m a fly] has met 8 dea? 9 ! endeavor to "w out untri$ pr9ciples on a full size ma*9e4 ,! fir/ co/ ( ! ma*9e1 ! cont9ual breakage & op]at+ exp5se1 to say no?+ ( ! damage suits & loss ( "t1 make a prelim9>y full size try\t an absurdity at ! pres5t "t4 ,aga91 ! results ( full size exp]im5ts are n always reliable1 z s mu* dep5ds ^u ! pilot & wea!r conditions4 ,! in/rum5ts us$ on a l>ge ma*9e are f> f be+ z accurate z ^? us$ 9 model te/s4 ,^! are also likely to be ?r[n out ( adju/m5t unkn[+ly by falls or collisions4 ,! great numb] ( v>iables t ent] into su* a te/ make x almo/ an impossibility to obta9 accurate data on ! result ( m9or alt]ations1 &1 9 fact1 x is almo/ impossible to get ! same results twice )\t fur!r alt]ations ?an *ang+ ! pilot4 ,full scale te/s are necess>y aft] suffici5t data has be5 obta9$ & appli$ 9 a sci5tific mann] to ! design ( ! ma*9e1 b successful p]=mance _c be expect$ f a p[]$ ma*9e built by guess "w4 ,:5 p]=m$ 9 connection ) a w9d tunnel1 or bas$ on dep5dable data f o!r s\rces1 full size w+ te/s are v in/ructive & useful if c>e is tak5 to h ! te/s conduct$ "u uni=m & kn[n conditions4 ,_m full size exp]im5ts ( ?is nature h be5 c>ri$ out by ,sa9t-,cyr ,univ]sity 9 ,france1 & by ! ,royal ,aircraft ,factory 9 ,great ,brita94 ,bo? ( ^! in/itutions h a w9d tunnel & an almo/ unlimit$ fund ( p]=mance data1 & la/ b n lea/1 h ! s]vices ( skill$ obs]v]s4 ,at ,sa9t-,cyr1 ! full size w+s1 or ! entire ma*9e1 are c>ri$ on an electric c> or *>iot4 ,! spe$ ( ! c>1 ! lift & drag1 c be det]m9$ at any mom5t dur+ ! run ?r\gh suitable record+ devices4 ,actual fly+ te/s h also be5 made1 ! measurem5t ( ! propell] ?ru/ giv+ ! drag1 :ile ! lift is kn[n z be+ equal to ! weight ( ! ma*9e4 ,! ,r4,a4,f4 h c>ri$ out a v ext5sive s]ies ( flight te/s1 ! exp]im5ts on ! old ,b4 ,e4-#b probably be+ ! be/ kn[n4 ,! great] "p ( ! exp]im5ts p]=m$ ) ! c> at ,sa9t-,cyr diff]$ consid]ably f ! results obta9$ by model te/s1 & app>5tly ^! diff]5ces foll[$ no specific law4 ,accord+ to !ory1 & ! results obta9$ by diff]5t laboratories1 ! p]=mance ( a full size w+ %\ld be bett] ?an ) a model1 b ! ,sa9t-,cyr te/s %[$ t su* 0 n always ! case4 ,! c5t] ( pressure movem5t diff]$ 9 almo/ e case1 & z a direct result1 ! pressure di/ribution ( ! l>ge w+s 0 mat]ially diff]5t ?an ) ! model4 ,! lift-drag ratio results v>i$1 sometimes be+ bett] = ! model ?an = ! l>ge w+4 ,^! diff]5ces c probably be expla9$ z be+ due to v>iation 9 air curr5ts1 side w9ds1 etc4 99,model ,te/s994 ,s9ce lift & resi/ance are due to relative motion betwe5 a body & ! air /ream1 a model c ei!r be t[$ ?r\gh ! air1 or x c be held /ation>y :ile ! air is =c$ pa/ x4 ,!re has be5 "s controv]sy on ! relation betwe5 ! results obta9$ by ! two me?ods1 b = ! pres5t we w accept ! common belief t ! results obta9$ by ei!r me?od are ! same4 ,9 te/+ %ip models1 !y are always t[$ ?r\gh ! tank1 b 9 ! case ( a]o-dynamic bodies ?is is complicat$ & n desirable4 ,9 t[+ models ?r\gh ! air a v high velocity is ne$$ & ?is necessitates ei!r a v long track or a %ort "t l5g? = mak+ ! obs]vations4 ,aga91 x is almo/ impossible to avoid errors because ( vibration1 inequality ( movem5t due to unev5 track1 or air eddies caus$ by diff]5ces 9 temp]ature & by ! movem5t ( ! t[+ device4 ,9 fact1 ! same difficulties apply to t[$ model te/s z to ! full size electric *>iot4 ,! :irl+ arm me?od ( te/+ z us$ by ,langley1 ,maxim-,vick]s1 & o!rs1 is a =m ( t[$ te/+1 b is also op5 to s]i\s objections4 ,unless ! arm is v long1 e "p ( ! model surface w n move at ! same velocity1 ! out] portions mov+ ! fa/]4 ,z ! =ces produc$ by an air /ream v>y z ! squ>e ( ! velocity1 ?is may introduce a s]i\s error4 ,! fact t ! body passes repeat$ly ov] ! same pa? introduces error1 z ! body aft] ! fir/ revolution is always work+ 9 di/urb$ air4 ,! c5trifugal =ce1 & ! curr5ts set up by ! arm itself all r$uce ! accuracy ( ! me?od4 ,:5 a model is plac$ 9 a uni=m curr5t ( air 9 a prop]ly design$ *annel or tunnel1 ! great] "p ( ! errors due to t[$ te/s are elim9at$4 ,! measur+ in/rum5ts c be plac$ on a firm f\ndation1 ! air /ream c be ma9ta9$ at a ne>ly uni=m spe$ & ) little error due to eddies1 & ! te/ may be cont9u$ "u uni=m conditions = an indef9ite p]iod4 ,:ile !re are m9or errors due to wall friction & slight v>iations 9 ! velocity at diff]5t po9ts 9 ! cross section ( ! tunnel1 !y are v small :5 comp>$ to ! errors ( t[+4 ,= ?is reason ! w9d tunnel is ! accept$ means ( te/+4 99,eiffel's ,w9d ,tunnel994 ,! ,eiffel ,laboratory at ,auteuil1 ,france1 is probably "o ( ! be/ kn[n4 ,! results 9 ,*apt]s ,,iii & ,v 7 obta9$ 9 ?is laboratory & ?\s&s ( simil> exp]im5ts h be5 c>ri$ out at ?is place4 ,two tunnels1 a l>ge & small1 are plac$ side by side 9 ! ma9 laboratory room1 ! tunnels be+ support$ midway betwe5 ! floor & ceil+4 ,! air is drawn f ?is room into an airtight exp]im5tal *amb] ?r\gh a bell-m\!d circul> op5+4 ,a grill or honeycomb baffle is plac$ 9 ! op5+ to /raight5 out ! fl[1 & f ?is po9t ! air passes across ! *amb] & exits ?r\gh a circul> duct to ! suction side ( a l>ge fan4 ,f ! fan ! air is dis*>g$ into ! room4 ,! same air ?us circulates ?r\gh ! tunnel cont9u\sly4 ,! te/ *amb] is consid]ably wid] ?an ! op5+s s t ! walls d n influ5ce ! fl[ ar\nd ! model4 ,a cyl9d] ( air passes ?r\gh ! *amb] at a rem>kably uni=m velocity1 & )\t any appreciable eddies4 ,diamet] ( ! /ream approximates #f4f feet 9 ! l>ge tunnel & #c feet 9 ! small]4 ,9 ! l>ge tunnel ! maximum velocity is #aje feet p] second1 & #aca feet p] second is atta9$ 9 ! small]4 ,a #ej-;horsep[] electric motor is us$ ) a multiblade fan ( ! ,sirocco type4 ,! obs]v] & weigh+ me*anism are support$ above ! air /ream on a slid+ floor1 & a /&>d ext5ds f ! model 9 ! w9d /ream to ! balances on ! weigh+ floor4 ,^! balances det]m9e ! lift & drag ( ! models1 ! c5t] ( pressure1 etc4 99,! ,n4 ,p4 ,l4 ,tunnel994 ,! ,national ,physical ,laboratory at ,t$d+ton1 ,engl&1 has a rem>kably complete & accurate a]odynamic equipm5t4 ,?is consi/s ( a l>ge tunnel ( #g squ>e feet area1 a small tunnel ( #d squ>e feet1 & a :irl+ table h\se4 ,! l>ge tunnel is #hj feet 9 l5g? ) an air fl[ ( #fj feet p] second1 ! air be+ circulat$ by a f\r-blad$ propell] driv5 by an electric motor ( #cj horsep[]4 ,! velocity is uni=m )9 "o-half p] c5t1 & ! mo/ accurate ( results h be5 obta9$4 ,! small] tunnel is ab\t #ef feet long & ! w9d velocity is ab\t #dj miles p] h\r maximum4 ,! propell] revolves at #fjj revolutions & is driv5 by a #aj-;horsep[] electric motor4 ,!re is no *amb] & ! models are susp5d$ 9 ! passage half way betwe5 ! ,diffus] 9 ! ent]+ end1 & ! baffles 9 ! exit4 ,! ,massa*usetts ,in/itute ( ,te*nology1 & ! ,curtis ,a]oplane ,company bo? h simil> tunnels4 99,unit$ ,/ates ,navy ,tunnel994 ,9 ?is tunnel ! air is conf9$ 9 a clos$ circuit1 ! return tunnel be+ mu* l>g] ?an ! section 9 :i* ! te/s are p]=m$4 ,! cross-sectional area is #h squ>e feet at ! po9t ( te/1 & ! /ream is uni=m )9 #b p] c5t4 ,! balance & controls are m\nt$ on ! ro( ( ! tunnel1 ) an arm ext5d+ d[n ?r\gh ! air /ream to ! model1 z 9 ! ,eiffel tunnel4 ,! balance is simil> to ,eiffel's & is s5sitive to less ?an #b_/ajjj p\nd4 ,a velocity ( #ge miles p] h\r may be atta9$ by ! #ejj-;horsep[] motor1 b on acc\nt ( ! heat+ ( ! air /ream ?r\gh sk9 friction1 ! te/s are g5]ally made at #dj miles p] h\r4 ,models up to #cf-;in* span c be te/$1 :ile ! majority ( models te/$ at ,m4 ,i4 ,t4 are ab\t #ah in*es4 ,,*apt] ,v4 ,,a]odynamics ,,( ,,lift+ ,,surfaces 7,,a](oils74 99,g5]al ,w+ ,requirem5ts994 ,! p]=mance ( flat plates :5 us$ z lift+ surfaces is v poor comp>$ ) curv$ sections or w+ =ms4 ,x w be rememb]$ t ! greate/ lift-drag ratio = ! flat plate 0 #f4d1 & ! be/ ,ky 0 #j4jjbid4 ,mod]n w+ sections h a lift-drag ratio ( ov] #bj4j1 & "s sections h a lift coeffici5t ( ,ky-#j4jjcfd1 or ab\t #fj p] c5t high] ?an ! lift obta9$ ) a flat plate4 ,9 fact1 ?is advantage made flight possible4 ,to ,langley1 above all o!r m51 we owe a debt ( gratitude = 8 inve/igations into ! value ( curv$ w+ surfaces4 99,air ,fl[ ,ab\t an ,a](oil994 ,to di/+ui% ! curv$ w+ f ! flat plane1 we w use ! t]m ,a](oil4 ,su* w+s are v>i\sly ref]r$ to z ,camb]$ surfaces1 ,ar*$ surfaces1 etc41 b ! t]m ,a](oil is m applicable to curv$ sections4 ,! v>iety ( =ms & curvatures is almo/ )\t limit1 "s a](oils be+ curv$ top & bottom1 :ile o!rs are curv$ only on ! upp] surface4 ,! curve on ! bottom face may ei!r be concave or convex1 an a](oil ( ! latt] type be+ g5]ally kn[n z ,d\ble camb]$4 ,! curves may be circul> arcs1 z 9 ! ,wright & ,nieuport w+s1 or an approximation to a p>abolic curve z ) _m ( ! mod]n w+s4 ,fig4 #a-;b %[s ! g5]al tr5d ( fl[ ab\t an a](oil at two diff]5t angles ( incid5ce1 ! fl[ 9 ! upp] view be+ *>act]i/ic = angles up to ab\t #f degrees1 :ile ! l[] view repres5ts ! fl[ at angles approximat+ #af4 ,at great] angles ! air /ream breaks away entirely f ! top surface & produces a turbul5ce t greatly resembles ! di/urbance produc$ by a flat plate4 ,x w be not$ 9 ! top figure 7,at small angles7 t ! fl[ is v simil> to ! fl[ ab\t a /reaml9e body1 & t ! air adh]es v closely to ! top surface4 ,! fl[ at small angles is v /eady & a m9imum ( turbul5ce is produc$ at ! trail+ edge4 ,illu/ration3 ,figs4 #a;a1 #a;b4 ,a](oil ,types & ,fl[ at ,diff]5t ,angles4 ,:5 increas$ beyond #f1 turbul5ce beg9s1 z %[n 9 ! l[] figure1 & a consid]able *ange takes place 9 ! lift-drag ratio4 ,?is is kn[n z ! ,l[] ,critical ,angle4 ,! turbul5ce1 h[ev]1 is conf9$ to ! aft] "p ( ! w+1 & little or no di/urbance takes place 9 ! locality ( ! l[] surface4 ,we obs]ve t an increase 9 angle & lift produces an increas$ turbul5t fl[ ab\t ! upp] surface1 & h5ce ! upp] surface is l>gely responsible = ! lift4 ,bel[ #aj ! tr5d ( ! upp] portion ( ! /ream is /ill approximately p>allel to ! upp] surface4 ,illu/ration3 ,fig4 #b4 ,%[+ ,h[ ,lift ,is ,obta9$ ,:5 an ,a](oil ,is ,incl9$ at a ,negative ,angle1 ! ,l9e ( ,flight ,be+ ,along ,x-,x4 ,f #af to #ah1 ! /ream sudd5ly breaks entirely away f ! w+ surface1 & produces an exce$+ly turbul5t fl[ & mass ( eddies4 ,! lift falls (f sudd5ly ) ! />t ( ! discont9u\s fl[4 ,! angle at :i* ?is drop 9 lift takes place is kn[n v>i\sly z ! ,second ,critical ,angle1 ! ,burble ,po9t1 or ! ,/all+ ,angle4 ,any fur!r increase 9 angle ov] ! /all+ angle causes a drop 9 lift z ! discont9uity is increas$4 ,) ! flat plane1 ! burble po9t occurs 9 ! neighborhood ( #cj & movem5t beyond ?is angle also decreases ! lift4 ,9 flight1 ! burble po9t %\ld n be approa*$1 = a slight increase 9 ! angle :5 ne> ?is po9t is likely to cause ! ma*9e to drop or ,/all4 ,! fact t ! maximum lift occurs at ! critical angle makes ! drop 9 lift at a slightly great] angle1 d\bly dang]\s4 ,a peculi> feature ( ! a](oil lies 9 ! fact t lift is /ill obta9$ ) a z]o angle ( incid5ce1 & ev5 ) a negative angle4 ,) ! a](oil %[n 9 ,fig4 #b !re w be a consid]able lift :5 ! flat bottom is p>allel ) ! direction ( travel1 & "s lift w /ill be obta9$ ) ! front edge dipp$ d[n 7,negative ,angle74 ,! curv$ upp] surface causes ! air /ream to rise t[>d ! front edge1 z at ,e1 h5ce ! w+ c be dipp$ d[n consid]ably 9 reg>d to ! l9e ( motion ,x-,x1 )\t go+ bel[ ! actual air /ream4 99,action 9 ,produc+ ,lift994 ,at comp>atively high angles ( incid5ce1 :]e !re is turbul5t fl[1 ! lift & drag are due pr9cipally to ! diff]5ce 9 pressure betwe5 ! upp] & l[] surfaces z 9 ! case ( ! flat plate4 ,!re is a positive pressure bel[ z 9 ! front ( a flat incl9$ plane1 & a vacu\s region above ! upp] surface4 ,! drag ) ! plane bel[ ! burble po9t1 & above ! ,l[] ,critical ,angle1 is due bo? to sk9 friction & turbul5ce--pr9cipally to ! latt]4 ,bel[ ! fir/ critical angle 7#f71 ! sk9 friction effect increases1 ow+ to ! clos5ess ) :i* ! air /ream hangs to ! upp] surface4 ,s9ce !re is b little turbul5ce at ! small angles bel[ #f1 ! !ory ( ! lift at ?is po9t is difficult to expla94 ,! be/ explanation ( lift at small angles is giv5 by ,kutta's ,vortex ,hypo!sis4 ,?is !ory is bas$ on ! fact t a w+ ) a practically /reaml9e fl[ produces a s]ies ( :irl+ vortices 7,:irlpools7 9 ! wake ( ! w+s1 & t ! =w>d movem5t ( ! plane produces ! en]gy t is /or$ 9 ! vortices4 ,! relation betwe5 ^! vortices is su*1 t :5 _! motion is de/roy$1 !y give up _! en]gy & produce a lift+ reaction by _! d[nw>d mom5tum4 ,! upw>d reaction on ! w+ is ?us equal & opposite to ! d[nw>d mom5tum ( ! air vortices4 99,drag ,compon5ts994 ,at l>ge angles ( incid5ce :]e turbul5ce exi/s1 ! lift & also ! drag are ne>ly proportional to ! velocity squ>$ 7,v74 ,:]e little turbul5ce exi/s1 & :]e ! air /ream hugs ! surface closely1 ! drag is due l>gely to sk9 friction1 & consequ5tly ?is "p ( ! drag v>ies accord+ to ,zahm's law ( friction 7,v74 ,= ?is reason x is difficult to e/imate ! diff]5ce 9 drag produc$ by diff]5ces 9 velocity1 s9ce ! two drag compon5ts v>y at diff]5t rates1 & !re is no fix$ proportion betwe5 !m4 ,s9ce ! frictional drag does n increase 9 proportion to ! area1 b z ,a41 difficulty is also exp]i5c$ 9 e/imat+ ! drag ( a full size w+ f data furni%$ by model te/s4 99,incid5ce & ,lift994 ,up to ! burble po9t ! lift increases ) an increase 9 ! angle2 b n at a uni=m rate = any "o a](oil1 nor at ! same rate = diff]5t a](oils4 ,! drag also increases ) ! angle1 b m rapidly ?an ! lift aft] an incid5ce ( ab\t #d is pass$1 h5ce ! lift-drag ratio is less at angles great] ?an #d4 ,decreas+ ! angle bel[ #d also decreases ! lift-drag1 b n s rapidly z ) ! l>g] angles4 ,at ! angle ( ,no ,lift ! drag is pr9cipally due to sk9 friction4 ,fig4 #c %[s a typical lift & incid5ce *>t t gives ! relation betwe5 ! angle ( incid5ce & ! lift coeffici5t4 ,?is curve v>ies greatly = diff]5t =ms ( a](oils bo? 9 %ape & num]ical value1 & x is only giv5 to %[ ! g5]al =m ( su* a graph4 ,! curve ly+ to ! left1 & above ! curve = ! ,flat plate1 is ! curve = ! p>ticul> a](oil %[n above ! *>t4 ,! ,lift-,coeffici5ts at ! left h& v]tical edge correspond to ! coeffici5t ,ky1 al?\gh ^! mu/ be multipli$ by a factor to conv]t !m into values ( ,ky4 ,z %[n1 !y are 9 t]ms ( ! ,absolute units us$ by ! ,national ,physical ,laboratory & to conv]t !m into ! ,ky unit !y mu/ be multipli$ by #j4jjea,v :]e ,v is 9 miles p] h\r1 or #j4jjbcfv :]e v feet p] second4 ,! incid5ce angle is 9 degrees4 ,illu/ration3 ,fig4 #c4 ,*>t ,%[+ ,relation ,betwe5 ,incid5ce ,& ,lift4 ,x w be not$ t ! lift ( ! a](oil is great] ?an t ( ! plate at e angle z ) ne>ly e practical a](oil4 ,! a](oil has a lift coeffici5t ( #j4jjbe at ! negative angle ( -#c1 :ile ! lift ( ! flat plate ( c\rse becomes z]o at #j4 ,z ! incid5ce ( ! a](oil increases ! lift coeffici5t also increases1 until x rea*es a maximum at ! burble po9t 7,/all+ angle7 ( ab\t #aa4e4 ,an increase ( angle f ?is po9t causes ! lift coeffici5t to drop rapidly until x rea*es a m9imum lift coeffici5t ( #j4df at #ag4 ,! flat plate z %[n1 rea*es a maximum at ! same angle1 b ! lift ( ! plate does n drop (f z rapidly4 ,! maximum coeffici5t ( ! a](oil is #j4eh & ( ! plate #j4da4 ,! rapid drop 9 pressure1 due to ! air /ream break+ away at ! burble po9t1 is cle>ly %[n by ! %>p peak 9 ! a](oil curve4 ,! %>pness ( ! drop v>ies among diff]5t a](oils1 ! peaks 9 "s =ms be+ v flat & uni=m = q a di/ance 9 a horizontal direction1 :ile o!rs are ev5 %>p] ?an t %[n4 ,ev]y?+ else be+ equal1 an a](oil ) a flat peak is ! m desirable z ! lift does n drop (f s rapidly 9 cases :]e ! aviator exce$s ! critical angle1 & h5ce ! t5d5cy to /all ! ma*9e is n z great4 ,?is =m ( *>t is probably ! simple/ =m to read4 ,x conta9s only "o quantity1 ! lift-coeffici5t1 & x %[s ! small v>iations m cle>ly ?an o!r types ( graphs 9 :i* ! values ( ,kx1 lift-drag1 & ! resultant =ce are all giv5 on a s+le %eet4 99,c5t] ( ,pressure ,movem5t994 ,z 9 ! case ( ! flat plate ! c5t] ( pressure on an a](oil surface v>ies ) ! angle ( incid5ce1 b unlike ! plate ! c5t] ( pressure 7,c4 ,p47 moves backw>d ) a decrease 9 angle4 ,! rapidity ( travel dep5ds ^u ! =m ( a](oil1 9 "s types ! movem5t is v great ) a small *ange 9 ! angle1 :ile 9 o!rs ! movem5t is almo/ negligible ?r\gh a wide range4 ,9 g5]al1 a](oils are inh]5tly un/able1 s9ce ! ,c4 ,p4 moves t[>d ! trail+ edge ) decreas$ angles1 & t5ds to aggravate a defici5cy 9 ! angle4 ,if ! angle is too small1 ! backw>d movem5t t5ds to make x /ill small]1 & ) an increas+ angle ! =w>d movem5t ( ! c5t] ( pressure t5ds to make ! angle /ill great]4 ,fig4 #d is a diagram %[+ ! c5t] ( pressure movem5t = a typical a](oil ) ! a](oil at ! top ( ! *>t4 ,! left side ( ! *>t repres5ts ! lead+ edge ( ! a](oil & ! "r side is ! trail+ edge1 :ile ! movem5t 9 p]c5tages ( ! *ord l5g? is %[n by ! figures along ! l[] l9e4 ,?us figure 4#c indicates t ! c5t] ( pressure is locat$ #j4c ( ! *ord f ! lead+ edge4 ,9 practice x is usual to measure ! di/ance ( ! ,c4 ,p4 f ! lead+ edge 9 ?is way4 ,illu/ration3 ,fig4 #d4 ,*>t ,giv+ ,relation ,betwe5 ,incid5ce & ,c4,p4 ,movem5t4 ,= an example 9 ! use ( ! *>t1 let u f9d ! location ( ! ,c4 ,p4 at angles ( #j1 #c & #g4 ,/>t+ ) ! column ( degrees at ! left h& edge ( ! *>t1 f9d #j1 & foll[ along ! dott$ l9e to ! "r until ! curve is rea*$4 ,f ?is po9t foll[ d[n to ! l[] r[ ( figures4 ,x w be f\nd t at #j ! ,c4 ,p4 lies ab\t half way betwe5 #j4e & #j4f1 or m exactly at #j4ee ( ! *ord f ! lead+ edge4 ,simil>ly at #c ! ,c4 ,p4 is at #j4cg ( ! *ord1 & at #g is at #j4c ( ! *ord4 ,f #aa to #ai1 ! ,c4 ,p4 = ?is p>ticul> a](oil moves v little1 rema9+ almo/ con/ant at #j4be ( ! *ord4 ,r$uc+ ! angle f #c causes ! ,c4 ,p4 to retreat v rapidly to ! re>1 s t at -#a ! ,c4 ,p4 is at #j4h ( ! *ord1 or v ne> ! trail+ edge ( ! w+4 99,o!r ,=ms ( ,*>ts994 ,! arrangem5t ( w+ p]=mance *>ts diff]s among ! v>i\s inve/igators4 ,"s *>ts %[ ! lift1 drag1 lift-drag ratio1 angle ( incid5ce1 c5t] ( pressure movem5t1 & resultant pressure on a s+le curve4 ,?is is v conv5i5t = ! exp]i5c$ eng9e]1 b is some:at complicat$ = ! beg9n]4 ,:atev] ! =m ( *>t1 !re %\ld be an outl9e draw+ ( ! a](oil describ$ 9 ! *>t4 ,fig4 #e %[s a *>t ( ! ,pol> v>iety 9 :i* f\r ( ! factors are %[n by a s+le curve4 ,?is type 0 orig9at$ by ,eiffel & is g5]ally excell5t1 except t ! *anges at small angles are n %[n v cle>ly or %>ply4 ,! curve illu/rates ! prop]ties ( ! ,kauffman w+1 or bett] kn[n z ! ,eiffel ,no4 #cg4 ,a m complete description ( ?is a](oil w be f\nd "u ! *apt] ,practical ,w+ ,sections4 ,a s+le curve is m>k$ at diff]5t po9ts ) ! angle ( incid5ce 7#j to #ab74 ,! column at ! left gives ! lift-coeffici5t ,ky1 :ile ! r[ at ! bottom ( ! %eet gives ! drag-coeffici5ts ,kx4 ,at ! top ( ! *>t are ! lift-drag ratios1 ea* figure be+ at ! end ( a diagonal l9e4 ,9 ?is way ! lift1 drag1 liftdrag & angle ( incid5ce are _h f a s+le curve4 ,take ! *>act]i/ics at an angle ( #aj degrees = example4 ,f9d ! angle ( #aj on ! curve1 & foll[ horizontally to ! left = ,ky4 ,! lift-coeffici5t w be f\nd to be #j4jjbf 9 t]ms ( miles p] h\r & p\nds p] squ>e foot4 ,foll[+ d[n f #aj1 x w be f\nd t ! drag-coeffici5t ,kx #j4jjjcf4 ,note ! diagonal l9es1 & t ! #aj po9t lies ne>e/ to ! diagonal head$ #g at ! top ( ! *>t4 7,x is m ne>ly a lift-drag ratio ( #g4cc ?an #g47 ,9 ! same way x w be f\nd t an angle ( #h degrees lies almo/ exactly on ! lift-drag diagonal m>k$ #i4 ,! be/ lift-drag is rea*$ at ab\t #b degrees at :i* po9t x is %[n z #ag4j4 ,! be/ lift-coeffici5t ,ky is #j4jjbgf at #ab degrees4 ,illu/ration3 ,fig4 #e4 ,pol> ,type ,*>t ,orig9at$ ,by ,eiffel4 ,a ?ird class ( *>t is %[n by ,fig4 #f4 ,?is s+le *>t %[s ?ree ( ! factors by means ( ?ree curves2 "o = ! lift-coeffici5t1 "o = ! drag-coeffici5t1 & "o = ! ,c4 ,p4 movem5t4 ,foll[ ! solid curves only1 = ! dott$ l9es are = comp>ison ) ! results obta9$ by ano!r laboratory 9 *eck+ ! *>act]i/ics ( ! w+4 ,! curves ref] to ! ,r4,a4,f4-#f section describ$ 9 ! *apt] on ,practical ,w+ ,sections4 ,! lift-coeffici5ts ,ky w be f\nd at ! "r ( ! *>t ) ! drag-coeffici5ts ,kx at ! left & 9 ! l[] column ( figures4 ,! upp] column at ! left is = ! ,c4 ,p4 movem5t & gives ! ,c4 ,p4 location 9 t]ms ( ! *ord l5g?4 ,! angles ( incid5ce w be f\nd at ! bottom4 ,values are 9 t]ms ( p\nds p] squ>e foot1 & miles p] h\r4 ,illu/ration3 ,fig4 #f4 ,*>t ( ,r4,a4,f4-#f ,w+ ,section ) ,?ree ,indep5d5t ,curves4 ,9 us+ ?is *>t1 />t ) ! angle ( incid5ce at ! bottom1 & foll[ up v]tically to ! lift or drag curves4 ,if ! value ( ,ky is desir$1 proce$ f ! requir$ incid5ce & up to ! ,lift curve1 !n horizontally to ! "r4 ,to obta9 ! drag1 foll[ up f ! angle ( incid5ce to ! drift curve1 & !n horizontally to ! left4 ,= ! position ( ! ,c4 ,p41 trace up f angle until ! ,c5t] ( ,pressure curve is rea*$1 & !n across horizontally to ! left4 ,if ! angle ( #h degrees is assum$1 ! lift-coeffici5t w be f\nd z ,ky #j4jjbb1 ! drag ,kx #j4jjjaf1 & ! c5t] ( pressure w be locat$ at #j4cb ( ! *ord f ! lead+ edge4 ,?is te/ 0 made ) ! air d5sity at #j4jgfjh p\nds p] cubic foot1 & at a spe$ ( #bi4he miles p] h\r4 ,! peak at ! burble po9t is fairly flat1 & gives a good range ( angle be=e ! lift drops to a s]i\s ext5t4 ,! a](oil ,r4,a4,f4-#f is a practical w+ =m us$ 9 _m ma*9es1 & ?is fact %\ld make ! *>t ( special int]e/4 99,surface ,calculations994 ,! calculation ( lift & drag = an a](oil are ! same z ^? = a flat plate1 t is1 ! total lift is express$ by ! =mula3 ,l ,ky,a,v :]e ,a is ! area 9 squ>e feet1 & ,v is ! velocity 9 miles p] h\r4 ,f ?is prim>y equation1 ! values ( ! area & velocity may be f\nd by transposition4 ,a ,l_/,ky,v & ,v ,l_/,ky,a4 ,! drag c be f\nd f ! old equation1 ,d ,kx,a,v1 or by divid+ ! lift by ! lift-drag ratio z 9 ! case ( ! flat plate4 99,example993 ,a w+ ( ! ,r4,a4,f4-#f =m has an area ( #bjj squ>e feet1 & ! spe$ is #fj miles p] h\r4 ,:at is ! lift at #f incid5ce8 99,solution994 ,f ,*>t ,no4 #f ! lift coeffici5t ,ky is #jjjahe at #f1 h5ce ! total lift is3 ,l ,ky,a,v #j4jjahe x #bjj x 7#fj x #fj7 #accb p\nds4 ,) an angle ( #h degrees1 & ) ! same spe$ & area1 ! lift becomes1 ,l #j4jjbb x #bjj x 7#fj x #fj7 #aehd p\nds4 ,! drag coeffici5t ,kx at an angle ( #f is #j4jjjab1 & at #h is #j4jjjaf4 ,! drag at #f becomes ,d ,kx,a,v #j4jjjab x #bjj x 7#fj x #fj7 #hf4d p\nds4 ,! lift-drag ratio at ?is angle is ,l_/,d #accb_/hfd #ae4d4 ,! drag at #h is ,d ,kx,a,v #j4jjjaf x #bjj x 7#fj x #fj7 #aae4b p\nds4 ,! lift-drag at #h is ,l_/,d #aehd_/aae4b #ac4h4 99,=ces ,act+ on ,a](oil994 ,fig4 #g is a section ?r\gh an a](oil ( a usual type1 ) a concave "u-surface ,9 an a](oil ( ?is "* all measurem5ts are made f ! *ordal l9e ,x-,x :i* is a /raight l9e drawn across 7& t\*+7 ! ent]+ & trail+ edges ( ! a](oil4 ,! angle made by ,x-,x ) ! horizontal is ! angle ( incid5ce 7i74 ,! wid? ( ! section1 measur$ f tip to tip ( ! ent]+ & trail+ edges1 is call$ ! ,*ord4 ,9 ?is figure ! ent]+ edge is at ! left4 ,! direction ( lift is ,up or z 9 ! case ( any a](oil1 acts away f ! convex side4 ,9 ! position %[n1 ) horizontal motion t[>d ! left1 ! lift =ce is indicat$ by ,l1 & ! horizontal drag =ce by ,d1 ! direction ( _! action be+ indicat$ by ! arr[ heads4 ,! =ce t is ! resultant ( ! lift & drag1 lies betwe5 !m1 & is %[n by ,r4 ,! po9t at :i* ! l9e ( ! resultant =ce int]sects ! *ordal l9e ,x-,x is call$ ! ,c5t] ( ,pressure 7,c4 ,p47 ,! resultant is n always at "r angles to ! *ordal l9e z %[n1 b may lie to ei!r side ( ?is "r angle l9e accord+ to ! angle ( incid5ce 7i74 ,a =ce equal to & 9 ! same direction z ,r1 w hold ! =ces ,l & ,d 9 equilibrium if appli$ at ! c5t] ( pressure 7,c4 ,p47 ,ow+ to ! diff]5ce 9 ! relative values ( ,l & ,d at v>i\s angles ( incid5ce1 ! angle made by ,r ) ! *ordal l9e mu/ v>y4 ,! lift & drag are always at "r angles to "o ano!r4 ,! resultant c be f\nd by draw+ bo? ! l9es ,l & ,d ?r\gh ! ,c4 ,p41 & at "r angles to "o ano!r1 & !n clos+ up ! p>allelogram by draw+ l9es p>allel to ,l & ,d f ! extreme ends ( ! latt]4 ,! resultant =ce 9 direction & ext5t w be ! diagonal ,r drawn across ! corn]s ( ! p>allelogram4 ,illu/ration3 ,fig4 #g4 ,=ces ,act+ on an ,a](oil1 ,lift1 ,drag1 & ,resultant4 ,relative ,w9d ,is f ,left to ,"r4 ,! =ces act+ on ! upp] & l[] surfaces are diff]5t1 bo? 9 direction & magnitude1 ow+ to ! fact t ! upp] & l[] surfaces d n contribute equally to ! support ( ! a](oil4 ,! upp] surface contributes f #fj to #hj p] c5t ( ! total lift4 ,a *ange 9 ! outl9e ( ! upp] curv$ surface vitally affects bo? ! lift & lift-drag1 b a *ange 9 ! l[] surface affects ! p]=mance to an almo/ negligible am\nt4 ,9 ! case ( ?9 circul> ar*$ plates ! curvature has a mu* m pron\nc$ effect4 ,:5 ! curvature ( a ?9 plate is increas$1 bo? ! upp] & l[] surfaces are increas$ 9 curvature1 & ?is und\bt$ly is ! cause ( ! great increase 9 ! lift ( ! %eet metal a](oils te/$ by ,eiffel4 ,! drag compon5t ( ! front upp] surface is ,negative1 t is1 acts ) ! horizontal =ce in/ead ( aga9/ x4 ,! l[] surface drag compon5t is ( c\rse oppos$ to ! horizontal propell+ =ce by en\gh to :olly ov]come ! assi/+ negative drag =ce ( ! front upp] surface4 ,! resultants v>y f po9t to po9t along ! section ( ! a](oil bo? 9 ext5t & direction4 ,a resultant true = ! ent]+ edge w\ld be entirely diff]5t at a po9t ne> ! trail+ edge4 99,di/ribution ( ,pressure994 ,to fully und]/& ! relative pressures & =ces act+ on diff]5t p>ts ( ! a](oil we mu/ ref] to ! exp]im5tal results obta9$ by ! ,eiffel & ! ,n4 ,p4 ,l4 laboratories4 ,9 ^! te/s small holes 7 drill$ ov] ! a](oil surface at giv5 int]vals1 ea* hole 9 turn be+ connect$ to a manomet] or pressure gauge1 & ! pressure at t po9t record$4 ,:ile ! read+ 0 be+ tak51 ! w9d 0 pass$ ov] ! surface s t ! pressures correspond$ to actual work+ conditions4 ,x 0 f\nd t ! pressure n only v>i$ 9 mov+ f ! ent]+ to trail+ edge1 b t x also v>i$ f ! c5t] to ! tips 9 mov+ along ! l5g? ( ! plane4 ,! rate ( v>iation diff]$ among diff]5t a](oils1 & ) ! same a](oil at diff]5t angles ( incid5ce4 ,on ! upp] surface1 ! suction or vacuum 0 g5]ally v high 9 ! imm$iate vic9ity ( ! ent]+ edge4 ,f ?is po9t x decreas$ until sometimes ! pressure 0 actually rev]s$ ne> ! trail+ edge & at ! latt] po9t !re 0 actually a d[nw>d pressure act+ aga9/ ! lift4 ,! positive pressure on ! "u surface rea*$ a maximum m ne>ly at ! c5t]1 & 9 _m cases !re 0 a vacuum ne> ! ent]+ edge or at ! trail+ edge4 ,) ne>ly all a](oils1 an increase 9 ! curvature result$ 9 a decid$ increase 9 ! vacuum on ! upp] surface1 p>ticul>ly ) ?9 a](oils curv$ to a circul> arc4 ,illu/ration3 ,fig4 #h4 ,pressure ,di/ribution = ,?9 ,circul> ,section4 ,fig4 #i4 ,%[s ! ,effect ( ,increas+ ! ,camb]4 7,eiffel7 ,by tak+ ! sum ( ! pressures at ! v>i\s p>ts ( ! surface1 x 0 f\nd t ! total correspond$ to ! lift ( ! entire a](oil1 ?us prov+ ! correctness ( ! inve/igation4 ,! sum ( ! drag =ces measur$ at ! diff]5t op5+s gave a l[] total ?an ! total drag measur$ by ! balance1 & ?is at once sugge/s t ! diff]5ce 0 due to ! sk9 friction effect t ( c\rse gave no pressure indication4 ,! tru? ( ?is d$uction is /ill fur!r prov$ by ! fact t ! drag values 7 m ne>ly equal at l>ge angles :]e ! turbul5ce =m$ a great] p]c5tage ( ! total drag4 ,figs4 #h1 #i1 #aj1 #aa1 #ab are pressure di/ribution curves tak5 along ! section ( sev]al a](oil surfaces4 ,^! are due to ,eiffel4 ,9 ,fig4 #h is ! pressure curve = a ?9 circul> a](oil section1 ! dep? ( ! curve measur$ f ! *ordal l9e be+ #a_/ac4e ( ! *ord4 ,! vacuum di/ribution ( ! upp] surface is indicat$ by ! upp] dott$ curve1 :ile ! pressure on ! bottom surface is giv5 by ! solid curve "u ! a](oil4 ,! pressures are giv5 by ! v]tical column ( figures at ! "r & are 9 t]ms ( in*es ( wat]1 t is1 ! pressure requir$ = ! support ( a wat] column ( ! specifi$ height4 ,figures ly+ above #j & m>k$ 7-71 ref] to a vacuum or negative pressures1 :ile ! figures bel[ z]o are positive pressures above ! atmosph]ic4 ,! ent]+ edge is at ! "r1 & ! angle ( incid5ce 9 all cases is #f4 ,x w be se5 t ! vacuum jumps up v sudd5ly to a maximum at ! lead+ edge1 & aga9 drops z sudd5ly to ab\t "o-half ! maximum4 ,f ?is po9t x aga9 gradually increases ne> ! c5t]1 & !n decl9es t[>d ! trail+ edge4 ,x w also be se5 t ! pressure on ! l[] surface1 giv5 by ! solid curve1 is f> less ?an ! pressure due to ! upp] surface4 ,s9ce ! l[] pressure curve crosses up1 & ov] ! z]o l9e at a po9t ne> ! trail+ edge1 x is evid5t t ! supp] surface ne> ! trail+ edge is "u a positive pressure1 or a pressure t acts d[n & aga9/ ! lift4 ,! pressures 9 any case are v m9ute1 ! maximum suction be+ #j4cedf in* ( wat]1 :ile ! maximum pressure on ! "u surface is only #j4jhe in*4 ,fig4 #i %[s ! effect ( increas+ ! curvature or camb]1 ! a](oil 9 ?is case hav+ a dep? equal to #a_/g ! *ord1 or ne>ly d\ble ! camb] ( ! fir/4 ,! %>p peak at ! ent]+ edge ( ! pressure curve is slightly r$uc$1 b ! rema9+ suction pressures ov] ! re/ ( ! surface are mu* increas$1 indicat+ a m>k$ increase 9 ! total pressure4 ,! pressure at ! c5t] is n[ ne>ly equal to ! front peak1 & ! pressure is g5]ally m ev5ly di/ribut$4 ,!re is a vacuum ov] ! entire upp] surface & a positive pressure ov] ! l[]4 ,! g5]al increase 9 pressure due to ! increas$ camb] is ! result ( ! great] d[nw>d deviation ( ! air /ream1 & ! correspond+ great] *ange 9 ! mom5tum ( ! air4 ,! spe$ at :i* ! te/s 7 made 0 #aj met]s p] second1 or #bb4d miles p] h\r4 ,! curves are only true at ! c5t] ( ! a](oil l5g? & = an aspect ratio ( #f4 ,! av]age pressure ov] ! entire surface 9 ,fig4 #h is #a4bjb p\nds p] squ>e foot1 & t ( ,fig4 #i is #a4ddj p\nds1 a diff]5ce ( #j4bch p\nd p] squ>e foot due to ! d\bl+ camb] 7#af4e p] c5t74 ,ano!r a](oil ) a camb] ( only #a_/bg gave an av]age pressure ( #j4hec p\nd p] squ>e foot "u ! same conditions4 ,a flat plane gave #j4edf4 ,tabulation ( ^! values w %[ ! results m cle>ly4 ,camb] ( ,av4 ,pres4 ,p] ,inc4 9 ,pres4 9 ,effici5cy ,surface ,sq4 ,ft4 ,lbs4_/,sq4 ,ft4 ,top4 ,bottom4 ,flat ,plane4 #j4edf #j4jjj #j4hi #j4aa #a_/bg #j4hec #j4cjg #j4gb #j4bh #a_/ac4e #a4bjb #j4cdi #j4ga #j4bi #a_/g #a4ddj #j4bch #j4ei #j4da ,9 ?is table1 ! ,effici5cies are ! relative lift effici5cies ( ! top & bottom surfaces4 ,= example1 9 ! case ( ! #a_/g camb] ! top surface lifts #ei p] c5t1 & ! bottom #da p] c5t ( ! total lift4 ,fig4 #aj is a ?9 a](oil ( p>abolic =m1 :ile ,fig4 #aa is an approximation to ! comp>atively ?ick w+ ( a bird4 ,9 bo? ^! sections x w be not$ t ! front peak is n mu* great] ?an ! second>y peak1 & t ! latt] is ne>] ! lead+ edge ?an ) ! circul> a](oils4 ,also t ! drop betwe5 ! peaks is small or entirely lack+4 ,! l[] surface ( ! trail+ edge is subject$ to a great] d[n pressure 9 ! case ( ! ?9 p>abola1 & !re is also a consid]able d[n pressure on ! upp] lead+ edge4 ,! pressure 9 ,fig4 #aj is #a4jj p\nd p] squ>e foot1 & t ( ,no4 #aa is #a4bje1 :ile ! effici5cy ( ! top surfaces is respectively #gb & #gd p] c5t4 ,illu/ration3 ,fig4 #aj4 ,?9 ,p>abolic ,a](oil ) ,pressure ,di/ribution4 ,fig4 #aa4 ,pressure ,di/ribution ( ,?ick ,bird's ,w+ ,type4 7,eiffel7 ,fig4 #ab %[s ! effect ( *ang+ ! angle ( ! bird w+ f z]o to #h degrees4 ,! lift p] squ>e foot 9 ea* case is %[n at ! upp] left h& corn] ( ! diagram :ile ! p]c5tages ( ! upp] & l[] surface lifts are includ$ above & bel[ ! w+4 ,= ^! curves ,i am indebt$ to ,e4 ,r4 ,arm/rong1 =m]ly ( ,a]o & ,hydro4 ,z ! angle is increas$1 ! suction ( ! upp] surface is mu* increas$ 7#j4eda to #a4cgj p\nds p] squ>e foot71 & ! pressure at ! lead+ edge increases f depression to a v long ?9 peak4 ,! maximum "u pressure is n mu* increas$ by ! angle1 b its di/ribution & av]age pressure are mu* alt]$4 ,at #j & #b ! usual pressure is r$uc$ to a vacuum ov] ! front ( ! section z %[n by ! l[] curve cross+ ov] ! upp] side ( ! w+1 & at ?is po9t ! "u surface sucks d[n & acts aga9/ ! lift4 ,illu/ration3 ,fig4 #ab4 ,effect ( ,incid5ce ,*anges on ! ,pressure ,di/ribution ( a ,?ick ,bird's ,w+4 7,aft] ,eiffel7 99,di/ribution ( ,drag ,=ces994 ,! drag z well z ! lift *anges 9 bo? direction & magnitude = diff]5t po9ts on ! w+4 ,9 ! front & upp] portions ! drag is ,negative1 t is1 in/ead ( produc+ head resi/ance to motion x really acts ) ! propell+ =ce4 ,h5ce on ! upp] & front portions ! lift is obta9$ ) no exp5diture ( p[]1 & 9 fact ?ru/ is giv5 up & add$ to t ( ! propell]4 ,! rema9+ drag elem5ts at ! re>1 & on ! l[] surface1 ( c\rse m ?an ov]come ?is desirable t5d5cy & give a positive drag = ! total w+4 ,! di/ribution is %[n by ,fig #ac :i* gives ! lift1 drag & resultant =ces at a numb] ( diff]5t po9ts on two circul> arc a](oils hav+ camb]s ( #a_/ac4e & #a_/g respectively4 ,9 ?is figure1 ! horizontal drag =ces are m>k$ ,d & d1 & ! direction ( ! drag is %[n by ! arr[s4 ,! lift is %[n by ,l & ! resultant by ,r z 9 ! ,fig4 #g4 ,z %[n1 ! arr[s po9t+ to ! "r are ! ,negative drag 7d7 =ces t assi/ 9 mov+ ! plane =w>d1 :ile ! drag indicat$ by arr[s 7,d7 po9t+ to ! left are ! drag =ces t oppose or resi/ ! horizontal motion4 ,) ! small] camb] 7#a_/ac4e7 ! drag =ces are v mu* small] ?an ^? ) ! heavi] camb] ( #a_/g1 & ! negative drifts 7d7 are correspond+ly small]4 ,all ( ! drag due to ! l[] surface1 po9t to ! left 7,d71 & h5ce produce head resi/ance to flight4 ,! drag to ! re> ( ! c5t] ( ! upp] surface are ! same4 ,9 front ( ! upp] c5t] we h "r h&1 or negative drifts 7d71 t aid ! motion4 ,^! =w>d =ces obta9$ by exp]im5t prove ! correctness ( ,lili5?al's ,=w>d ,tang5tial !ory advanc$ _m ye>s ago4 ,illu/ration3 ,fig4 #ac4 ,direction ( ,drag ,ov] ,diff]5t ,portions ( ,circul> ,arc - ,a](oils4 ,illu/ration3 ,fig4 #ad;a4 ,di/ribution = ,wright ,w+4 7b7 ,m4 ,f>man ,w+4 7c7 ,breguet ,w+4 7d7 ,bl]iot ,w+4 7e7 ,bl]iot #aa-;,bis4 ,illu/ration3 ,fig4 #ae4 ,pressure ,di/ribution at ,v>i\s ,po9ts ,along ! ,l5g? ( a ,nieuport ,monoplane ,w+4 99,di/ribution on ,practical ,w+s994 ,) ! exception ( ! bird w+1 ! di/ributions h be5 giv5 = ?9 plates t are ( little value on an a]oplane4 ,!y d n p]mit ( /rong /ructural memb]s = c>ry+ ! load4 ,! actual w+ mu/ h consid]able ?ickness1 z %[n by ! a](oils 9 ,figs4 #a1 #b1 #c1 etc41 & are ( approximately /ream l9e =m4 ,fig4 #ad %[s ! di/ribution = actual a]oplane w+s3 7a7 ,wright1 7b7 ,m4 ,f>man1 7c7 ,breguet1 7d7 ,bl]iot #aa47;d71 7e7 ,bl]iot #aa-;bis4 ,! ,wright w+ is v blunt & has an exce$+ly high lift at ! lead+ edge4 ,! ,m4 ,f>man1 :i* is slightly less blunt1 has a simil> b l[] front peak4 ,! ,breguet is ( a m mod]n type ) ! maximum ?ickness ab\t #be p] c5t f ! lead+ edge4 ,! latt] %[s a rem>kably ev5 di/ribution ( pressure1 & is !re=e a bett] type z w be se5 f ! relative lifts ( #j4iaf & #j4ihf p\nds p] squ>e foot4 ,! lift-drag ratio ( ! ,breguet is also bett]1 ow+ to ! great] pr$om9ance ( ! negative drag compon5ts4 ,decreas+ ! ?ickness & ! und]camb] ( ,bl]iot #aa1 result$ 9 an unusual increase ( #aj p] c5t ( ! "u pressure1 & a decrease 9 ! ,suction1 %[n by ,bl]iot #aa-;bis4 ,! ,bl]iot has ! %>pe/ ent]+ edge & ! lea/ upp] pressure4 ,9 ! above practical w+ sections ! aspect ratio is v>iable1 be+ ! same 9 ! te/ model z 9 ! full-size ma*9e4 ,! ,bl]iot be+ a monoplane has a l[] aspect ratio 7#e71 ?an ! biplanes 7a71 7b7 & 7c74 ,! ,breguet ) an aspect ( #h has a lift ( #j4ihf p\nds p] squ>e foot z aga9/ ! #j4gha ( ! ,bl]iot1 & und\bt$ly "p ( ?is diff]5ce is due to ! aspect ratio4 ,! pressure falls (f ar\nd ! tips z %[n by ! successive sections tak5 ?r\gh a ,nieuport monoplane w+ 9 ,fig4 #ae4 ,section 7f7 0 tak5 ne> ! body & %[s ! great] lift4 ,section 7g7 is midway betwe5 ! tips & body1 & 7h7 & 7i7 are progressively ne>] ! tips4 ,z we proce$ t[>d ! tips f ! body ! pressure falls (f z %[n 9 ! sections1 ?is r$uc+ f #a4jg to #j4ee p\nds p] squ>e foot4 ,?is w+ also ?9s d[n t[>d ! tips or wa%es out1 z x is call$4 ,illu/ration3 ,fig4 #af4 ,%[+ ,pressure ,di/ribution on ! ,plan ,view ( a ,typical ,w+1 ,lead+ ,edge ,along ,a-,a1 ,trail+ ,edge ,d-,c4 ,c5t] ( ,pressure4 ,m>k$ ,c4,p4 ,! ,proportion ,pressures ,are ,indicat$ by ! ,%ad+ on ! ,surface1 ! ,pressure ,be+ ,negative at ! ,tips & ,ne> ! ,re> ,edge4 ,,*apt] ,,vi4 ,,practical ,,w+ ,,sections4 99,developm5t ( ,mod]n ,w+s994 ,! fir/ practical results obta9$ by ,wright ,bro!rs1 ,montgom]y1 ,*anute1 ,h5son1 ,curtiss1 ,langley1 & o!rs1 7 obta9$ by ! use ( camb]$ w+s4 ,! l[ value ( ! lift-drag ratio1 due to ! flat planes us$ by ! e>li] exp]im5t]s1 0 pr9cipally ! cause ( _! failure to fly4 ,! ,wrights *ose w+s ( v heavy camb] s t a maximum lift c\ld be obta9$ ) a m9imum spe$4 ,^! e>ly w+s _h ! v fair lift-drag ratio ( #ab to #a4 ,mod]n w+ sections h be5 develop$ t give a lift-drag ratio ( well ov] #bj to #a1 al?\gh ?is is att5d$ by a consid]able loss 9 ! lift4 ,z be=e expla9$1 ! total lift ( a w+ surface dep5ds on ! =m ( ! w+1 its area1 & ! spe$ ^u :i* x moves 9 relation to ! air4 ,travel+ at a l[ spe$ requires ei!r a w+ ) a high lift co-effici5t or an increas$ area4 ,) a con/ant value = ! lift-drag ratio1 an increase 9 ! lift value ( ! w+ section is pref]able to an increase 9 area1 s9ce ! l>g] area necessitates heavi] /ructural memb]s1 m expos$ brac+1 & h5ce1 m head resi/ance4 ,un=tunately1 x is n always possible to use ! sections giv+ ! heavie/ lift1 = ! reason t su* sections usually h a poor lift-drag ratio4 ,9 ! practical ma*9e1 a compromise mu/ be effect$ betwe5 ! drag ( ! w+s & ! drag or head resi/ance ( ! /ructural p>ts s t ! comb9$ or total head resi/ance w be at a m9imum4 ,9 mak+ su* a compromise1 x mu/ be rememb]$ t ! head resi/ance ( ! /ructural p>ts pr$om9ates at high spe$s1 :ile ! drag ( ! w+s is ! mo/ important at l[ spe$s4 ,9 ! e>ly days ( fly+1 ! fact t an a]oplane left ! gr\nd 0 a suffici5t pro( ( its excell5ce1 b n[adays ! "q ( effici5cy "u diff]5t conditions ( flight 7p]=mance7 is an ess5tial4 ,ea* new a]oplane is c>efully te/$ = spe$1 rate ( climb1 & load+4 ,spe$ range1 or ! relation betwe5 ! l[e/ & highe/ possible flight spe$s1 is also ( increas+ importance1 ! mo/ c>eful calculations be+ made to obta9 ?is desirable quality4 99,p]=mance994 ,to improve ! p]=mance ( an a]oplane1 ! design] mu/ increase ! ratio ( ! horsep[] to ! weight1 or 9 o!r words1 mu/ ei!r use great] horsep[] or decrease ! weight c>ri$ by a giv5 p[]4 ,?is result may be obta9$ by improvem5ts 9 ! motor1 or by improvem5ts 9 ! ma*9e itself4 ,improvem5ts 9 ! a]oplane may be atta9$ 9 sev]al ways3 7#a7 by cutt+ d[n ! /ructural weight2 7#b7 by increas+ ! effici5cy ( ! lift+ surfaces2 7#c7 by decreas+ ! head resi/ance ( ! body & expos$ /ructural p>ts1 & 7#d7 by adju/m5t ( ! area or camb] ( ! w+s s t ! angle ( incid5ce c be ma9ta9$ at ! po9t ( greate/ plane effici5cy4 ,at pres5t we are pr9cipally conc]n$ ) item 7#b71 al?\gh 7#d7 foll[s z a directly relat$ item4 ,improvem5t 9 ! w+ *>act]i/ics is pr9cipally a subject = ! w9d tunnel exp]im5tali/1 s9ce ) our pres5t k1 x is impossible to compute ! p]=mance ( a w+ by direct ma!matical me?ods4 ,hav+ obta9$ ! *>act]i/ics ( a numb] ( w+ sections f ! a]odynamic laboratory1 ! design] is 9 a position to proce$ ) ! calculation ( ! areas1 p[]1 etc4 ,at pres5t ?is is r a matt] ( elim9ation1 or survival ( ! fitte/1 z ea* w+ is tak5 sep>ately & comput$ ?r\gh a c]ta9 range ( p]=mance4 99,w+ ,load+994 ,! basic unit = w+ lift is ! load c>ri$ p] unit ( area4 ,9 ,engli% units ?is is express$ z be+ ! weight 9 p\nds c>ri$ by a squ>e foot ( ! lift+ surface4 ,practically1 ?is value is obta9$ by divid+ ! total load$ weight ( ! ma*9e by ! w+ area4 ,?us1 if ! weight ( a ma*9e is #b1ejj p\nds 7load$71 & ! area is #ejj squ>e feet1 ! unit load+ w be3 w #b1ejj_/ejj #e p\nds p] squ>e foot4 ,9 ! metric sy/em ! unit load+ is giv5 9 t]ms ( kilogrammes p] squ>e met]4 ,conv]sely1 ) ! total weight & load+ kn[n1 ! area c be comput$ by divid+ ! weight by ! unit load+4 ,! unit load+ adopt$ = a giv5 ma*9e dep5ds ^u ! type ( ma*9e1 its spe$1 & ! w+ section adopt$1 ?is quantity v>y+ f #c4e to #aj p\nds p] squ>e foot 9 usual practice4 ,z w be se51 ! load+ is high] = small fa/ ma*9es ?an = ! sl[] & l>g] types4 ,a v good s]ies ( w+s has be5 develop$1 rang+ f ! l[ resi/ance type c>ry+ #e p\nds p] squ>e foot at #de miles p] h\r1 to ! high lift w+1 :i* gives a lift ( #g4e p\nds p] squ>e foot at ! same spe$4 ,! m$ium lift w+ w be assum$ to c>ry #f p\nds p] squ>e foot at #de miles p] h\r4 ,! w+ c>ry+ #g4e p\nds p] squ>e foot gives a great sav+ 9 area ov] ! l[ lift type at #e p\nds p] squ>e foot1 & !re=e a great sav+ 9 weight4 ,! weight sav$ is n due to ! sav+ 9 area alone1 b is also due to ! r$uction 9 /ress & ! correspond+ r$uction 9 ! size & weight ( ! /ructural memb]s4 ,fur!r1 ! small] area requires a small] tail surface & a %ort] body4 ,a r\gh approximation gives a sav+ ( #a4e p\nds p] squ>e foot 9 favor ( ! #g4e p\nd w+ load+4 ,?is mat]ially increases ! horsep[] weight ratio 9 favor ( ! high lift w+1 & ) ! r$uction 9 area & weight comes an improvem5t 9 ! vision range ( ! pilot & an increas$ ease 9 h&l+ 7except 9 dives74 ,! high lift types 9 a dive h a l[ limit+ spe$4 ,z an (fset to ^! advantages1 ! drag ( ! high lift type ( w+ is s great at small angles t z soon z ! weight p] horsep[] is increas$ beyond #ah p\nds we f9d t ! spe$ range ( ! l[ resi/ance type increases f> beyond t ( ! high lift w+4 ,accord+ to ,w+ ,comm&] ,s$don1 ( ! ,engli% ,navy1 a sc\t plane ( ! future equipp$ ) l[ resi/ance w+s w h a spe$ range ( f #ej to #aej miles p] h\r4 ,! same ma*9e equipp$ ) high lift w+s w\ld h a range ( only #ej to #ajj miles p] h\r4 ,an excess ( p[] is ( value ) l[ resi/ance w+s1 b is increas+ly wa/eful z ! lift co-effici5t is increas$4 ,l&+ spe$s h a great influ5ce on ! type ( w+ & ! area1 s9ce ! l[ spe$s necess>y = ! av]age ma*9es require a high lift w+1 great area1 or bo?4 ,) ! pres5t w+ sections1 l[ flight spe$s are obta9$ ) a sacrifice 9 ! high spe$ values4 ,9 ! same way1 high spe$ ma*9es mu/ l& at dang]\sly high spe$s4 ,at pres5t1 ! be/ range t we c hope = ) fix$ areas is ab\t two to "o2 t is1 ! high spe$ is n mu* m ?an twice ! l[e/ spe$4 ,a ma*9e ) a l[ spe$ ( #de miles p] h\r _c be dep5d$ ^u to safely develop a maximum spe$ ( mu* ov] #ij miles p] h\r1 = at high] spe$s ! angle ( incid5ce w be s dim9i%$ z to come dang]\sly ne> to ! position ( no lift4 ,9 any case1 ! travel ( ! c5t] ( pressure w be s great at extreme w+ angles z to cause consid]able manipulation ( ! elevator surface1 result+ 9 a fur!r increase 9 ! resi/ance4 99,resi/ance & ,p[]994 ,! horizontal drag 7resi/ance7 ( a w+1 det]m9es ! p[] requir$ = its support s9ce ?is is ! =ce t mu/ be ov]come by ! ?ru/ ( ! propell]4 ,! drag is a compon5t ( ! weight support$ & !re=e dep5ds ^u ! load+ & ^u ! effici5cy ( ! w+4 ,! drag ( ! av]age mod]n w+1 /ructural resi/ance neglect$1 is ab\t #a_/af ( ! weight support$1 al?\gh !re are sev]al sections t give a drag z l[ z #a_/bc ( ! weight4 ,! d5om9ators ( ^! fractions1 su* z #af & #bc1 are ! lift-drag ratios ( ! w+ sections4 ,drag 9 any w+ section is a v>iable quantity1 ! drag v>y+ ) ! angle ( incid5ce4 ,9 g5]al1 ! drag is at a m9imum at an angle ( ab\t #d degrees1 ! value increas+ rapidly on a fur!r increase or decrease 9 ! angle4 ,usually a high lift section has a great] drag ?an ! l[ lift type at small angles1 & a small] drag at l>ge angles1 al?\gh ?is latt] is n inv>iably ! case4 99,p[] ,requirem5ts994 ,p[] is ! rate ( do+ "w1 or ! rate at :i* resi/ance is ov]come4 ,) a con/ant resi/ance ! p[] w be increas$ by an increase 9 ! spe$4 ,) a con/ant spe$1 ! p[] w be increas$ by an increase 9 ! resi/ance4 ,num]ically1 ! p[] is ! product ( ! =ce & ! velocity 9 feet p] second1 feet p] m9ute1 miles p] h\r1 or met]s p] second4 ,! mo/ common ,engli% p[] unit is ! horsep[]1 :i* is obta9$ by multiply+ ! resi/+ =ce 9 p\nds by ! velocity 9 feet p] m9ute1 ?is product be+ divid$ by #cc1jjj4 ,if ,d is ! horizontal drag 9 p\nds1 & v velocity ( ! w+ 9 feet p] m9ute1 ! horsep[] ,h w be express$ by3 ,h ,dv _/ #cc1jjj ,s9ce ! spe$ ( an a]oplane is seldom giv5 9 feet p] m9ute1 ! =mula = horsep[] c be giv5 9 t]ms ( miles p] h\r by3 ,h ,,dv _/ #cge ,:]e ,v velocity 9 miles p] h\r1 ,d & ,h rema9+ z be=e4 ,! total p[] = ! entire ma*9e w\ld involve ! sum ( ! w+ & /ructural drags1 ) ,d equal to ! total resi/ance ( ! ma*9e4 99,example994 ,! total weight ( an a]oplane is f\nd to be #c1jjj p\nds4 ,! lift-drag ratio ( ! w+s is #ae4jj1 & ! spe$ is #ij miles p] h\r4 ,f9d ! p[] requir$ = ! w+s alone4 99,solution994 ,! total drag ( ! w+s w be3 ,d #c1jjj_/ae #bjj p\nds4 ,! horsep[] requir$3 ,h ,,dv_/#cge #bjj #ij_/cgedh horsep[]4 ,x %\ld be rememb]$ t ?is is ! p[] absorb$ by ! w+s1 ! actual motor p[] be+ consid]ably great] ow+ to losses 9 ! propell]4 ,) a propell] effici5cy ( #gj p] c5t1 ! actual motor p[] w become3 ,hm #dh_/j4gjfh4eg = ! w+s alone4 ,to include ! effici5cy into our =mula1 we h3 ,h ,,dv_/#cge;,e :]e ,e propell] effici5cy express$ z a decimal4 ,! great] ! propell] effici5cy1 ! less w be ! actual motor p[]1 h5ce ! great necessity = an effici5t propell]1 especially 9 ! case ( pu%] type a]oplanes :]e ! w+s d n ga9 by ! increas$ slip /ream4 ,! propell] ?ru/ mu/ be equal & opposite to ! drag at ! v>i\s spe$s1 & h5ce ! ?ru/ v>ies ) ! plane load+1 w+ section1 & angle ( incid5ce4 ,portions ( ! w+ surfaces t lie 9 ! propell] slip /ream h a great] lift ?an ^? ly+ outside ( ?is zone because ( ! great] velocity ( ! slip /ream4 ,= accurate results1 ! area 9 ! slip /ream %\ld be det]m9$ & calculat$ = ! increas$ velocity4 ,(t5times x is desirable to obta9 ! ,unit drag2 t is1 ! drag p] squ>e foot ( lift+ surface4 ,?is c be obta9$ by divid+ ! lift p] squ>e foot by ! lift-drag ratio1 c>e be+ tak5 to note ! angle at :i* ! unit drag is requir$4 99,advantages ( ,camb]$ ,sections ,summ>iz$994 ,mod]n w+ sections are always ( ! camb]$1 d\ble-surface type = ! foll[+ reasons3 #a4 ,!y give a bett] lift-drag ratio ?an ! flat surface1 & !re=e are m economical 9 ! use ( p[]4 #b4 ,9 ! majority ( cases !y give a bett] lift p] squ>e foot ( surface ?an ! flat plate & require less area4 #c4 ,! camb]$ w+s c be made ?ick] & w accommodate heavi] sp>s & /ructural memb]s )\t excessive head resi/ance4 99,prop]ties ( ,mod]n ,w+s994 ,! curvature ( a w+ surface c be/ be se5 by cutt+ out a section along a l9e p]p5dicul> to ! l5g? ( ! w+1 & !n view+ ! cut portion f ! end4 ,x is f ?is me?od ( illu/ration t ! diff]5t w+ curves1 or types ( w+s1 are kn[n z w+ sections4 ,9 all mod]n w+s ! top surface is well curv$1 & 9 ! majority ( cases ! bottom surface is also giv5 a curvature1 al?\gh ?is is v small 9 _m in/ances4 ,fig4 #a4 %[s a typical w+ section ) ! names ( ! diff]5t p>ts & ! me?ods ( dim5sion+ ! curves4 ,all measurem5ts to ! top & bottom surfaces are tak5 f ! /raight *ordal l9e or datum l9e m>k$ ,x-,x4 ,?is l9e is drawn across ! concave und]surface 9 su* a way z to t\* ! surface only at two po9ts1 "o at ! front & "o at ! re> ( ! w+ section4 ,! incl9ation ( ! w+ ) ! direction ( flight is always giv5 z ! angle made by ! l9e ,x-,x ) ! w9d4 ,?us1 if a c]ta9 w+ is said to h an angle ( incid5ce equal to #d degrees1 we "k t ! *ordal l9e ,x-,x makes an angle ( #d degrees ) ! direction ( travel4 ,?is angle is g5]ally designat$ by ! lett] 7i71 & is also kn[n z ! angle ( attack4 ,! di/ance f ! extreme front to ! extreme re> edge 7wid? ( w+7 is call$ ! *ord wid? or m commonly ! *ord4 ,9 measur+ ! curve1 ! datum l9e ,x-,x is divid$ into a numb] ( equal p>ts1 usually #aj1 & ! l9es #a-b-c-d-e-f-g-h-i-aj-aa are drawn p]p5dicul> to ,x-,x4 ,ea* ( ! v]tical numb]$ l9es is call$ a /ation1 ! l9e ,no4 #c be+ call$ ,/ation #c1 & s on4 ,! v]tical di/ance measur$ f ,x-,x to ei!r ( ! curves along "o ( ! /ation l9es is kn[n z ! ord9ate ( ! curve at t po9t4 ,?us1 if we "k ! ord9ates at ea* /ation1 x is a simple matt] to draw ! /raight l9e ,x-,x1 divide x into #aj p>ts1 & !n lay (f ! heights ( ! ord9ates at ! v>i\s /ations4 ,! di/ances f datum to ! upp] curve are kn[n z ! ,upp] ord9ates1 :ile ! same measurem5ts to ! "u surface are kn[n z ! ,l[] ord9ates4 ,?is me?od all[s u to quickly draw any w+ section f a table t gives ! upp] & l[] ord9ates at ! diff]5t /ations4 ,a common me?od ( express+ ! value ( ! dep? ( a w+ section 9 t]ms ( ! *ord wid? is to give ! ,camb]1 :i* is num]ically ! result obta9$ by divid+ ! dep? ( ! w+ curve at any po9t by ! wid? ( ! *ord4 ,usually ! camb] giv5 = a w+ is tak5 to be ! maximum camb]2 t is1 ! camb] tak5 at ! po9t ( greate/ dep?4 ,?us1 if we he> t a c]ta9 w+ has a camb] ( #j4jhi1 we take x = grant$ t ?is is ! camb] at ! deepe/ portion ( ! w+4 ,! correct me?od w\ld be to give #j4jhi z ! maximum camb] 9 ord] to avoid confusion4 ,to obta9 ! maximum camb]1 divide ! maximum ord9ate by ! *ord4 ,illu/ration3 ,fig4 #a4 ,section ,?r\gh a ,typical ,a](oil or ,w+1 ! ,p>ts & ,measurem5ts ,be+ ,m>k$ on ! ,section4 ,! ,horizontal ,wid? or ,*ord ,is ,divid$ ,into #aj ,equal ,p>ts or ,/ations1 & ! ,height ( ! ,top & ,bottom ,curves ,are ,measur$ f ! ,*ordal ,l9e ,x-,x at ,ea* ,/ation4 ,! ,v]tical ,di/ance f ! ,*ordal ,l9e ,is ! ,ord9ate at ! ,po9t ( ,measurem5t4 99,example994 ,! maximum ord9ate ( a c]ta9 w+ is #e in*es1 & ! *ord is #dj in*es4 ,:at is ! maximum camb]8 ,! maximum camb] is #e_/dj #j4abe4 ,9 o!r words1 ! maximum dep? ( ?is w+ is #ab4e p] c5t ( ! *ord1 & unless o!rwise specifi$1 is tak5 z be+ ! camb] ( ! top surface4 ,! maximum camb] ( a mod]n w+ is g5]ally 9 ! neighborhood ( #j4jh1 al?\gh !re are sev]al ,successful sections t are well bel[ ?is figure4 ,un=tunately1 ! camb] is n a direct index to ! value ( a w+1 ei!r 9 reg>d to lift+ ability or effici5cy4 ,by kn[+ ! camb] ( a w+ we _c directly calculate ! lift or drag1 = !re are sev]al examples ( w+s hav+ widely diff]5t camb]s t give practically ! same lift & drift4 ,at ! pres5t "t1 we c only det]m9e ! *>act]i/ics ( a w+ by exp]im5t1 ei!r on a full size w+ or on a scale model4 ,9 ! be/ w+ sections1 ! greate/ ?ickness & camb] occurs at a po9t ab\t #j4c ( ! *ord f ! front edge1 ?is edge be+ mu* m blunt & abrupt ?an ! portions ne> ! trail+ edge4 ,an effici5t w+ tap]s v gradually f ! po9t ( maximum camb] t[>ds ! re>4 ,?is is usually a s\rce ( difficulty f a /ructural /&po9t s9ce x is difficult to get an effici5t dep? ( w+ beam at a po9t ne> ! trail+ edge4 ,a numb] ( exp]im5ts p]=m$ by ! ,national ,physical ,laboratory %[ t ! position ( maximum ord9ate or camb] %\ld be locat$ at #cc4b p] c5t f ! lead+ edge4 ,?is location gives ! greate/ lift p] squ>e foot1 & also ! lea/ resi/ance = ! weight lift$4 ,plac+ ! maximum ord9ate fur!r =w>d is worse ?an plac+ x to ! re>4 ,?ick5+ ! ent]+ edge causes a proportionate loss 9 effici5cy4 ,?ick5+ ! re> edge also decreases ! effici5cy b does n affect ! weight lift+ value to any great ext5t4 ,! camb] ( ! "u surface seems to h b little effect on ! effici5cy1 b ! lift increases slightly ) an increase 9 ! camb] ( ! l[] surface4 ,increas+ ! camb] ( ! l[] surface decreases ! ?ickness ( ! w+ & h5ce decreases ! /r5g? ( ! support+ memb]s1 p>ticul>ly at po9ts ne> ! trail+ edge4 ,! increase ( lift due to increas+ ! "u camb] is s slight z to be h>dly wor? ! sacrifice 9 /r5g?4 ,v>iations 9 ! camb] ( ! upp] surface are ( mu* great] importance4 ,x is on ?is surface t ! great] "p ( ! lift takes places1 h5ce a *ange 9 ! dep? ( ?is curve1 or 9 its outl9e1 w cause wid] v>iations 9 ! *>act]i/ics ( ! w+ ?an w\ld be ! case ) ! "u surface4 ,increas+ ! upp] camb] by ab\t #fj p] c5t may d\ble ! lift ( ! upp] surface1 b ! relation ( ! lift to ! drag is increas$4 ,f ?is1 x w be se5 t direct calculations f ! outl9e w\ld be mo/ difficult1 & 9 fact a practical impossibility at ! pres5t "t4 ,illu/ration3 ,fig4 #b4 7,upp]74 ,%[s a ,slight ,reflex or ,upw>d ,turn ( ! ,trail+ ,edge4 ,fig4 #c4 7,l[]7 ,%[s an ,excessive ,reflex ,:i* ,greatly ,r$uces ! ,c4,p4 ,movem5t4 ,by putt+ a rev]se curve 9 ! trail+ edge ( a w+1 z %[n by ,fig4 #b1 ! /ability ( ! w+ may be increas$ to a surpris+ degree1 b ! lift & effici5cy are correspond+ly r$uc$ ) ea* increase 9 ! am\nt ( rev]se curvature4 ,9 ?is way1 /ability is atta9$ at ! exp5se ( effici5cy & lift+ p[]4 ,) ! re> edge rais$ ab\t #j4jcg ( ! *ord1 ! ,n4 ,p4 ,l4 f\nd t ! c5t] ( pressure c\ld be held /ation>y1 b ! loss ( lift 0 ab\t #be p] c5t & ! loss ( effici5cy am\nt$ practically #ab p] c5t4 ,) v slight rev]se curvatures x has be5 possible to ma9ta9 ! lift & effici5cy1 & at ! same "t to keep ! c5t] ( pressure movem5t d[n to a reasonable ext5t4 ,! ,new ,u4,s4,a4 sections & ! ,eiffel ,no4 #cb section are examples ( excell5t sections 9 :i* a slight rev]se or reflex curvature is us$4 ,! ,eiffel #cb w+ is effici5t1 & at ! same ! c5t] ( pressure movem5t betwe5 incid5t angles ( #j & #aj is practically negligible4 ,?is w+ is ?9 9 ! neighborhood ( ! trail+ edge1 & x is v difficult to obta9 a /rong re> sp>4 99,w+ ,selection994 ,no s+le w+ section is adapt$ to all purposes4 ,"s w+s give a great lift b are ineffici5t at small angles & ) light load+4 ,!re are o!rs t give a l[ lift b are v effici5t at ! small angles us$ on high spe$ ma*9es4 ,z be=e expla9$1 !re are v /able sections t give b poor results :5 consid]$ f ! /&po9t ( lift & effici5cy4 ,! selection ( any "o w+ section dep5ds ^u ! type ( ma*9e ^u :i* x is to be us$1 :e!r x is to be a small spe$ ma*9e or a heavy fly+ boat or bomb+ plane4 ,!re are a multitude ( w+ sections1 ea* possess+ c]ta9 admirable features & also c]ta9 faults4 ,to li/ all ( ! w+s t h be5 tri$ or propos$ w\ld require a book _m times ! size ( ?is1 & = ?is reason ,i h kept ! li/ ( w+s conf9$ to ^? t h be5 mo/ commonly employ$ on prom95t ma*9es1 or t h %[n evid5ce ( highly desirable & special qualities4 ,?is selection has be5 made ) a view ( includ+ w+s ( widely v>y+ *>act]i/ics s t ! data c be appli$ to a wide range ( a]oplane types4 ,w+s suitable = bo? spe$ & weight c>ry+ ma*9es h be5 includ$4 ,! w+s describ$ are ! ,u4,s4,a4 ,sections ,no4 #a1 #b1 #c1 #d1 #e & #f2 ! ,r4,a4,f4 ,sections ,nos4 #c & #f1 & ! well kn[n ,eiffel ,w+s ,no4 #cb1 #cf & #cg4 ,! data giv5 = ^! w+s is obta9$ f w9d tunnel te/s made at ! ,massa*usetts ,in/itute ( ,te*nology1 ! ,national ,physical ,laboratory 7,engl&71 & ! ,eiffel ,laboratory 9 ,p>is4 ,= ea* ( ^! sections ! lift co-effici5t 7,ky71 ! lift-drift ratio 7,l_/,d71 & ! drag co-effici5t 7,kx7 are giv5 9 t]ms ( miles p] h\r & p\nds p] squ>e foot4 ,s9ce ^! are ! results = model w+s1 !re are c]ta9 corrections to be made :5 ! full size w+ is consid]$1 ^! corrections be+ made necess>y by ! fact t ! drag does n v>y at ! same rate z ! lift4 ,?is ,size or ,scale correction is a function ( ! product ( ! w+ span 9 feet by ! velocity ( ! w9d 9 feet p] second4 ,a l>ge value ( ! product results 9 a bett] w+ p]=mance1 or 9 o!r words1 ! l>ge w+ w always give bett] lift-drag ratios ?an w\ld be indicat$ by ! model te/s4 ,! lift co-effici5t ,ky is practically unaffect$ by v>iations 9 ! product4 ,if ! model te/s are tak5 )\t correction1 ! design] w always be on ! safe side 9 calculat+ ! p[]4 ,! me?od ( mak+ ! scale corrections w be tak5 up lat]4 ,( all ! sections describ$1 ! ,r4,a4,f4-#f is probably ! be/ kn[n4 ,! data on ?is w+ is mo/ complete1 & 9 reality x is a sort ( /&>d by :i* ! p]=mance ( o!r w+s is comp>$4 ,data has be5 publi%$ :i* describes ! p]=mance ( ! ,r4,a4,f4-#f us$ 9 monoplane1 biplane & triplane =m2 & ) almo/ e conceivable degree ( /agg]1 sweep back1 & decalage4 ,9 addition to ! laboratory data1 ! w+ has also be5 us$ ) great success on full size ma*9es1 pr9cipally ( ! ,prim>y tra9] class :]e an ,all ar\nd class ( w+ is p>ticul>ly desirable4 ,x is excell5t f a /ructural /&po9t s9ce ! section is comp>atively deep 9 ! vic9ity ( ! trail+ edge4 ,! ,u4,s4,a4 sections are ( comp>atively rec5t developm5t & are decid$ improvem5ts on ! ,r4,a4,f4 & ,eiffel sections4 ,! only objection is ! limit$ am\nt ( data t is available on ^! w+s--limit$ at lea/ :5 ! ,r4,a4,f4 data is consid]$--z we h only ! figures = ! monoplane arrangem5t4 99,,w+ ,,selection499 997#a7 ,lift-,drag ,ratio994 ,! lift-drag ratio 7,l_/,d7 ( a w+ is ! measure ( w+ effici5cy4 ,num]ically1 ?is is equal to ! lift divid$ by ! horizontal drag1 bo? quantities be+ express$ 9 p\nds4 ,! great] ! weight support$ by a giv5 horizontal drag1 ! less w be ! p[] requir$ = ! propulsion ( ! a]oplane1 h5ce a high value ( ,l_/,d indicates a desirable w+ section--at lea/ f a p[] /&po9t4 ,9 ! expression ,l_/,d1 ,l lift 9 p\nds1 & ,d horizontal drag 9 p\nds4 ,un=tunately1 ?is is n ! only important factor1 s9ce a w+ hav+ a great lift-drag is usually defici5t 9 lift or is sometimes /ructurally weak4 ,! lift-drag ratio v>ies ) ! angle ( incid5ce 7i71 rea*+ a maximum at an angle ( ab\t #d 9 ! majority ( w+s4 ,! angle ( incid5ce at :i* ! lift-drag is a maximum is g5]ally tak5 z ! angle ( incid5ce = normal horizontal flight4 ,at angles ei!r great] or less1 ! ,l_/,d falls (f1 g5]ally at a v rapid rate1 & ! p[] increases correspond+ly4 ,v effici5t w+s may h a ratio high] ?an ,l_/,d#bj at an angle ( ab\t #d1 :ile at #af incid5ce ! value may be r$uc$ to ,l_/,d #d1 or ev5 less4 ,! lift is g5]ally greate/ at ab\t #af4 ,! am\nt ( v>iation 9 ! lift1 & lift-drag1 correspond+ to *anges 9 ! incid5ce diff]s among ! diff]5t types ( w+s & mu/ be det]m9$ by actual te/4 ,aft] f9d+ a w+ ) a good value ( ,l_/,d1 ! value ( ! lift co-effici5t ,ky %\ld be det]m9$ at ! angle ( ! maximum ,l_/,d4 ,) two w+s hav+ ! same lift-drag ratio1 ! w+ hav+ ! greate/ lift 7,ky7 at ?is po9t is ! mo/ desirable w+ z ! great] lift w require less area & w !re=e result 9 less head resi/ance & less weight4 ,any increase 9 ! area n only increases ! weight ( ! w+ surface prop]1 b also increases ! wir+ & weights ( ! /ructural memb]s4 ,) heavy ma*9es1 su* z seaplanes or bomb dropp]s1 a high value ( ,ky is necess>y if ! area is to be kept )9 practical limits4 ,a small fa/ sc\t+ plane requires ! be/ possible lift-drag ratio at small angles1 b requires only a small lift co-effici5t4 ,at spe$s ( ov] #ajj miles p] h\r a small increase 9 ! resi/ance w cause a great increase 9 ! p[]4 997#b7 ,maximum ,lift 7,ky7994 ,) a giv5 w+ area & weight1 ! maximum value ( ! lift co-effici5t 7,ky7 det]m9es ! sl[ spe$1 or l&+ spe$1 ( ! a]oplane4 ,! great] ! value ( ,ky1 ! sl[] c be ! l&+ spe$4 ,= safety1 ! l&+ spe$ %\ld be z l[ z possible4 ,9 ! majority ( w+s1 ! maximum lift occurs at ab\t #af ( incid5ce1 & 9 sev]al sections ?is maximum is fairly well su/a9$ ov] a consid]able range ( angle4 ,! angle ( maximum lift is v>i\sly kn[n z ! ,/all+ angle or ! ,burble po9t1 s9ce a *ange ( angle 9 ei!r direction r$uces ! lift & t5ds to /all ! a]oplane4 ,= safety1 ! angle range = maximum lift %\ld be z great z possible1 = if ! lift falls (f v rapidly ) an increase 9 ! angle ( incid5ce1 ! pilot may easily increase ! angle too f> & drop ! ma*9e4 ,9 ! ,r4,a4,f4-#c w+1 ! lift is little alt]$ ?r\gh an angle range ( f #ad to #af4e1 ! maximum occurr+ at #ae4g1 :ile ) ! ,r4,a4,f4-#d1 ! lift drops v sudd5ly on increas+ ! angle above #ae4 ,! range ( ! /all+ angle 9 any ( ! w+s c be increas$ by suitable biplane or triplane arrangem5ts4 ,if l>ge values ( lift are accompani$ by a fairly good ,l_/,d value at l>ge angles1 ! w+ section w be suitable = heavy ma*9es4 997#c7 ,c5t] ( ,pressure ,movem5t994 ,! c5t] ( pressure movem5t ) v>y+ angles ( incid5ce is ( ! greate/ importance1 s9ce x n only det]m9es ! longitud9al /ability b also has an important effect ^u ! load+ ( ! w+ sp>s & ribs4 ,) ! majority ( w+s a decrease 9 ! angle ( incid5ce causes ! c5t] ( pressure to move back t[>d ! trail+ edge & h5ce t5ds to cause nose div+4 ,:5 decreas$ beyond #j ! movem5t is v %>p & quick1 ! ,c4 ,p4 mov+ ne>ly half ! *ord wid? 9 ! *ange f #j to -#a4e4 ,! small] ! angle1 ! m rapid w be ! movem5t4 ,betwe5 #f & #af1 ! c5t] ( pressure lies ne> a po9t #j4c ( ! *ord f ! ent]+ edge 9 ! majority ( w+ sections4 ,r$uc+ ! angle f #f to #b moves ! ,c4 ,p4 back to approximately #j4d ( ! *ord f ! ent]+ edge4 ,!re are w+ sections1 h[ev]1 9 :i* ! ,c4 ,p4 movem5t is exce$+ly small1 ! ,eiffel #cb be+ a notable example ( ?is type4 ,?is w+ is exce$+ly /able1 z ! ,c4 ,p4 rema9s at a trifle m ?an #j4cj ( ! *ord ?r\gh ne>ly ! total range ( flight angles4 ,an a]oplane equipp$ ) ! ,eiffel #cb w+ c\ld be provid$ ) exce$+ly small tail surfaces )\t a t5d5cy to dive4 ,%\ld ! elevator become inop]ative ?r\gh accid5t1 ! ma*9e c\ld probably be l&$ )\t dang]4 ,?is w+ has c]ta9 objectionable features1 h[ev]1 t (fset ! advantages4 ,x w be not$ t ) ! un/able w+s ! c5t] ( pressure movem5t always t5ds to aggravate ! w+ attitude4 ,if ! ma*9e is div+1 ! decrease 9 angle causes ! ,c4 ,p4 to move back & /ill fur!r increase ! div+ t5d5cy4 ,if ! angle is sudd5ly increas$1 ! ,c4 ,p4 moves =w>d & increases ! t5d5cy t[>d /all+4 ,if ! c5t] ( pressure c\ld be held /ation>y at "o po9t1 ! w+ sp>s c\ld be arrang$ s t ea* sp> w\ld take its prop] proportion ( ! load4 ,z x is1 ei!r sp> may be call$ ^u to c>ry any:]e f ?ree-f\r?s ( ! load to entire load1 s9ce at extreme angles ! ,c4 ,p4 is likely to lie directly on ei!r ( ! sp>s4 ,s9ce ! re> sp> is always %all[ & ineffici5t1 ?is is mo/ undesirable4 ,?is condition alone to a c]ta9 ext5t c\nt]balances ! /ructural disadvantage ( ! ?9 ,eiffel #cb section4 ,al?\gh ! sp>s 9 ?is w+ mu/ ( necessity be %all[1 !y c be arrang$ s t ea* sp> w take its prop] %>e ( ! load & ) ! assurance t ! load+ w rema9 con/ant ?r\gh\t ! range ( flight angles4 ,! comp>atively deep front sp> c\ld be mov$ back until x c>ri$ ! great] "p ( ! load1 ?us reliev+ ! re> sp>4 ,) a good lift-drag ratio1 & a comp>atively high value ( ,ky1 ! c5t] ( pressure movem5t %\ld be an important consid]ation 9 ! selection ( a w+4 ,x %\ld be rememb]$ 9 ?is reg>d t ! /ability effects ( ! ,c4 ,p4 movem5t c be (fset to a consid]able ext5t by suitable biplane arrangem5ts4 997#d7 ,/ructural ,consid]ations994 ,= l>ge1 heavy ma*9es1 ! /ructural factor (t5 ranks 9 importance ) ! lift-drag ratio & ! lift co-effici5t4 ,x is also ( extreme importance 9 spe$ sc\ts :]e ! numb] ( int]plane /ruts are to be at a m9imum & :]e ! b5d+ mom5t on ! w+ sp>s is likely to be great 9 consequ5ce4 ,a deep1 ?ick w+ section p]mits ( deep /rong w+ sp>s4 ,! /r5g? ( a sp> increases ) ! squ>e ( its dep?1 b only 9 direct proportion to its wid?4 ,?us1 d\bl+ ! dep? ( ! sp> increases ! /r5g? f\r times1 :ile d\bl+ ! wid? only d\bles ! /r5g?4 ,! increase 9 weight w\ld be ! same 9 bo? cases4 ,:ile v deep w+s are n usually effici5t1 :5 consid]$ f ! w+ section te/s alone1 ! total effici5cy ( ! w+ con/ruction :5 m\nt$ on ! ma*9e is great] ?an w\ld be suppos$4 ,?is is due to ! lightness ( ! sp>s & to ! r$uction 9 head resi/ance made possible by a great] spac+ ( ! int]plane /ruts4 ,?us1 ! deep w+ alone may h a l[ ,l_/,d 9 a model te/1 b its /ructural advantages give a high total effici5cy = ! ma*9e assembl$4 99,summ>y994 ,x w be se5 f ! =ego+ matt] t ! selection ( a w+ consi/s 9 mak+ a s]ies ( compromises & t no s+le w+ section c be expect$ to fulfill all conditions4 ,) ! purpose ( ! propos$ a]oplane ?or\ghly 9 m9d1 ! v>i\s sections are tak5 up "o by "o1 until a w+ is f\nd t mo/ usefully compromises ) all ( ! conditions4 ,r$uc+ ?is inve/igation to its simple/ elem5ts we mu/ foll[ ! r\t9e z describ$ above3 7#a7 ,lift-drift ratio & value ( ,ky at ?is ratio4 7#b7 ,maximum value ( ,ky & ,l_/,d at ?is lift4 7#c7 ,c5t] ( pressure movem5t4 7#d7 ,dep? ( w+ & /ructural *>act]i/ics4 99,calculations = ,lift & ,area994 ,al?\gh ! pr9ciples ( surface calculations 7 describ$ 9 ! *apt] on elem5t>y a]odynamics1 x w probably simplify matt]s to review ^! calculations at ?is po9t4 ,! lift ( a w+ v>ies ) ! product ( ! area1 & ! velocity squ>$1 ?is result be+ multipli$ by ! co-effici5t ( lift 7,ky74 ,! co-effici5t v>ies ) ! w+ section1 & ) ! angle ( incid5ce4 ,/at$ z a =mula3 ,l ,ky,a,v :]e ,a area 9 squ>e feet1 & ,v velocity ( ! w+ 9 miles p] h\r4 ,assum+ an area ( #bjj squ>e feet1 a velocity ( #hj miles p] h\r1 & ) ,k #j4jjbe1 ! total life 7,l7 becomes3 ,l ,ky,a,v #j4jjbe x #bjj x 7#hj #hj7 #c1bjj p\nds4 ,assum+ a lift-drag ratio ( #af1 ! drag ( ! w+1 or its resi/ance to horizontal motion1 w be express$ by ,d ,l_/r#c1bjj_/afbjj p\nds1 :]e r lift-drag ratio4 ,x is ?is resi/ance ( #bjj p\nds t ! motor mu/ ov]come 9 driv+ ! w+s ?r\gh ! air4 ,! total resi/ance (f]$ by ! a]oplane w be equal to ! sum ( ! w+ resi/ance & ! head resi/ance ( ! body1 /ruts1 wir+ & o!r /ructural p>ts4 ,9 ! pres5t in/ance we w consid] only ! resi/ance ( ! w+s4 ,:5 ! lift co-effici5t1 spe$1 & total lift are kn[n1 ! area c be f\nd f ,a ,l_/,ky,v1 ! lift1 ( c\rse1 be+ tak5 z ! total weight ( ! ma*9e4 ,! area ( ! support+ surface = a spe$ ( #fj miles p] h\r1 total weight ( #b1djj p\nds1 & a lift co-effici5t ( #j4jjb is calculat$ z foll[s3 ,a ,l_/,ky,v #b1djj_/j4jjb 7#fj #fj7 #ccc sq4 ft4 ,a ?ird v>iation 9 ! =mula is t us$ 9 f9d+ ! value ( ! lift co-effici5t = a p>ticul> w+ load+4 ,f ! weight1 spe$ & area1 we c f9d ! co-effici5t ,ky1 & ) ?is value we c f9d a w+ t w correspond to ! requir$ co-effici5t4 ,?is me?od is p>ticul>ly conv5i5t :5 se>*+ = ! section ) ! greate/ lift-drag ratio4 ,ky ,l_/,,av1 or :5 ! load+ p] squ>e foot is kn[n1 ! co-effici5t becomes ,ky ,l'_/,v4 ,= example1 let u f9d ! co-effici5t = a w+ load+ ( #e p\nds p] squ>e foot at a velocity ( #hj miles p] h\r4 ,ins]t+ ! num]ical values into ! equation we h1 ,ky ,l'_/,v #e_/7hj #hj7 #j4jjjgh4 ,any w+1 at any angle t has a lift co-effici5t equal to #j4jjjgh w support ! load at ! giv5 spe$1 al?\gh _m ( ! w+s w\ld n give a satisfactory lift-drag ratio ) ?is co-effici5t4 ,x %\ld be not$ 9 ! above calculations t no correction has be5 made = ,scale1 aspect ratio or biplane int]f]5ce4 ,9 o!r words1 we h assum$ ! figures z apply+ to model monoplanes4 ,9 ! foll[+ tables ! lift1 lift-drag & drag mu/ be correct$1 s9ce ?is data 0 obta9$ f model te/s on monoplane sections4 ,! effects ( biplane int]f]5ce w be describ$ 9 ! *apt] on ,biplane & ,triplane ,arrangem5t1 b x may be /at$ t sup]pos+ ! planes r$uces bo? ! lift co-effici5t & ! liftdrag ratio1 ! am\nt ( r$uction dep5d+ ^u ! relative gap betwe5 ! surfaces4 ,?us ) a gap equal to ! *ord1 ! lift ( ! biplane surface w only be ab\t #hj p] c5t ( ! lift ( a monoplane surface ( ! same area & section4 99,w+ ,te/ ,data994 ,! data giv5 9 ?is *apt] is ! result ( w9d tunnel te/s made "u /&>d conditions1 ! great] "p ( ! results be+ publi%$ by ! ,massa*usetts ,in/itute ( ,te*nology4 ,! te/s 7 all made on ! same size ( model & at ! same w9d spe$ s t an accurate comp>ison c be made betwe5 ! diff]5t sections4 ,all values are = monoplane w+s ) an aspect ratio ( #f1 ! laboratory models be+ #ahx#c in*es4 ,! exception to ! above te/ conditions w be f\nd 9 ! tables ( ! ,eiffel #cg & #cf sections1 ^! figures be+ tak5 f ! results ( ,eiffel's laboratory4 ,! ,eiffel models 7 #ce4dx#e4i in*es & 7 te/$ at w9d velocities ( #bb4d1 #dd4h1 & #fg4b miles p] h\r4 ,! te/s made at ,m4 ,i4 ,t4 7 all made at a w9d spe$ ( #cj miles p] h\r4 ,! lift co-effici5t ,ky is practically indep5d5t ( ! w+ size & w9d velocity1 b ! drag co-effici5t ,kx v>ies ) bo? ! size & w9d velocity1 & ! v>iation is n ! same = ! diff]5t w+s4 ,! results ( ! ,m4 ,i4 ,t4 te/s 7 publi%$ 9 ,aviation & ,a]onautical ,eng9e]+ by ,alex&] ,klem9 & ,g4 ,m4 ,d5k+]4 99,! ,r4,a4,f4 ,w+ ,sections994 ,^! w+s are probably ! be/ kn[n ( all w+s1 al?\gh !y are inf]ior to ! new ,u4,s4,a4 sections4 ,!y are ( ,engli% orig91 be+ develop$ by ! ,royal ,aircraft ,factory 7,r4,a4,f471 ) ! te/s p]=m$ by ! ,national ,physical ,laboratory at ,t$d+ton1 ,engl&4 ,! ,r4,a4,f4-#f is ! ne>e/ approa* to ! all ar\nd w+1 ?is section hav+ a fairly high ,l_/,d ratio & a good value ( ,ky = ne>ly all angles4 ,x is by no means a spe$ w+ nor is x suitable = heavy ma*9es1 b x comprises well betwe5 ^! limits & has be5 ext5sively us$ on m$ium size ma*9es1 su* z ! ,curtiss ,,jn#d-;,b1 ! ,london & ,prov9cial1 & o!rs4 ,! ,r4,a4,f-#c has a v high value = ,ky1 & a v good lift-drag ratio = ! high-lift values4 ,x is suitable = seaplanes1 bomb dropp]s & o!r heavy ma*9es ( a l nature t fly at l[ or mod]ate spe$s4 ,! outl9es ( ^! w+s are %[n by ,figs4 #g & #h1 & ! camb] ord9ates are m>k$ z p]c5tages ( ! *ord4 ,9 lay+ out a w+ rib f ^! diagrams1 ! ord9ate at any po9t is obta9$ by multiply+ ! *ord l5g? 9 in*es by ! ord9ate factor at t po9t4 ,ref]r+ to ! ,r4,a4,f4-#c diagram1 ,fig4 #h1 x w be se5 t ! ord9ate = ! upp] surface at ! ?ird /ation f ! ent]+ edge is #j4jfd4 ,if ! *ord ( ! w+ is #fj in*es1 ! height ( ! upp] curve measur$ above ! datum l9e ,x-,x at ! ?ird /ation w be1 #j4jfd #fj #c4hd in*es4 ,at ! same /ation1 ! height ( ! l[] curve w be1 #j4jaf #fj #j4if in*4 ,! *ord is divid$ into #aj equal p>ts1 & at ! ent]+ edge "o ( ! t5 p>ts is subdivid$ s z to obta9 a m accurate curve at ?is po9t4 ,9 "s w+ sections x is absolutely necess>y to subdivide ! fir/ *ord division z ! curve *anges v rapidly 9 a %ort di/ance4 ,! upp] curve1 especially at ! ent]+ edge1 is by f> ! mo/ active "p ( ! section & = ?is reason p>ticul> c>e %\ld be ex]cis$ 9 gett+ ! correct outl9e at ?is po9t4 ,illu/ration3 ,figs4 #g-h4 ,r4,a4,f4 ,w+ ,sections4 ,ord9ates z ,decimals ( ! ,*ord4 99,a]odynamic ,prop]ties ( ! ,r4,a4,f4 ,sections994 ,table #a gives ! values ( ,ky1 ,kx1 ,l_/,d1 & ! c5t] ( pressure movem5t 7,c4 ,p47 = ! ,r4,a4,f4-#c section ?r\gh a range ( angles v>y+ f -#b to #bj4 ,! fir/ column at ! left gives ! angles ( incid5ce 7i71 ! correspond+ values = ! lift 7,ky7 & ! drag 7,kx7 be+ giv5 9 ! second & ?ird columns1 respectively4 ,! f\r? column gives ! lift-drag ratio 7,l_/,d74 ,! fif? & la/ column gives ! location ( ! c5t] ( pressure = ea* diff]5t angle ( incid5ce1 ! figure indicat+ ! di/ance ( ! ,c4 ,p4 f ! ent]+ edge express$ z a decimal "p ( ! *ord4 ,z an example 9 ! use ( ! table1 let x be requir$ to f9d ! lift & drag ( ! ,r4,a4,f4-#c section :5 incl9$ at an angle ( #f & propell$ at a spe$ ( #ij miles p] h\r4 ,! assum$ area w be #cjj squ>e feet4 ,at #f x w be f\nd t ! lift co-effici5t ,ky is #j4jjbcfi4 ,f our =mulae1 ! lift w be3 ,l ,ky,a,v or num]ically1 ,l#j4jjbcfi #cjj 7#ij #ij7 #e1gefg lbs4 ,at ! same spe$1 b ) ! angle ( incid5ce r$uc$ to #b1 ! lift w be r$uc$ to ,l #j4jjaeed #cjj x 7#ij #ij7 #c1ggf4b p\nds1 :]e #j4jjaeed is ! lift co-effici5t at #b4 ,x w be not$ t ! maximum lift co-effici5t occurs at #ad & cont9ues at ?is value to a little pa/ #ae4 ,! lift at ! /all+ angle is fairly con/ant f #ab to #af4 ,! value ( ! drag c be f\nd 9 ei!r ( two ways3 7#a7 by divid+ ! total lift 7,l7 by ! lift-drag ratio1 or 7#b7 by figur+ its value by ! =mula ,d ,kx,a,v4 ,! fir/ me?od is %ort] & pref]able4 ,by consult+ ! table1 x w be se5 t ! ,l_/,d ratio at #f is #ad4i4 ,! total w+ drag w !n be equal to #e1gef4g_/adi #chf4d lbs4 ,figur$ by ! second me?od1 ! value ( ,ky at #f is #j4jjjaei1 & ! drag is !re=e3 ,d ,kx,a,v #j4jjjaei #cjj 7#ij #ij7 #chf4d4 ,?is *ecks exactly ) ! fir/ me?od4 ,! lift-drag ratio is be/ at #d1 ! figure be+ #ae4f1 :ile ! lift at ?is po9t is #j4jjaifc4 ,) ! same area & spe$1 ! total lift ( ! surface at ! angle ( be/ lift-drift ratio w be #jjjaifc #cjj 7#ij #ij7 #d1ggj lbs4 ,at #d ! c5t] ( pressure is #j4che ( ! *ord f ! ent]+ edge4 ,if ! *ord is #fj in*es wide1 ! c5t] ( pressure w be locat$ at #j4che #fj #bc4a in*es f ! ent]+ edge4 ,at #ae1 ! c5t] ( pressure w be #j4bi #fj #ag4d in*es f ! ent]+ edge1 or dur+ ! *ange f #d to #ae ! c5t] ( pressure w h mov$ =w>d by #e4g in*es4 ,at -#b1 ! pressure has mov$ ov] ?ree-qu>t]s ( ! way t[>d ! trail+ edge -#j4ghe ( ! *ord1 to be exact ,?r\gh ! ord9>y flight angles ( f #b to #ab1 ! travel ( ! c5t] ( pressure is n excessive4 ,! maximum lift co-effici5t 7,ky7 is v high 9 ! ,r4,a4,f4-#c section1 rea*+ a maximum ( #j4jjcdha at an incid5ce ( #ad4 ,?is is second to only "o o!r w+1 ! section ,u4,s4,a4-#d4 ,?is makes x suitable = heavy seaplanes4 ,table #b gives ! a]odynamic prop]ties ( ! ,r4,a4,f-#f w+1 ! table be+ arrang$ 9 a mann] simil> to t ( ! ,r4,a4,f4-#c4 ,9 glanc+ d[n ! column ( lift co-effici5ts 7,ky71 & comp>+ ! values ) ^? ( ! ,r4,a4,f4-#c section1 x w be not$ t ! lift ( ,r4,a4,f4-#f is mu* l[] at e angle ( incid5ce1 b t ! lift-drag ratio ( ! latt] section is n always correspond+ly high]4 ,at e angle bel[ #b1 at #f1 & at angles above #ad1 ! ,l_/,d ratio ( ! ,r4,a4,f4-#c is sup]ior 9 spite ( its great] lift4 ,! maximum ,l_/,d ratio ( ! ,r4,a4,f4-#f at #d is #af4eh1 :i* is consid]ably high] ?an ! be/ ,l_/,d ratio ( ! ,r4,a4,f4-#c4 ,! be/ lift co-effici5t ( ! ,r4,a4,f4-#f1 #jjjcjde1 is v mu* l[] ?an ! maximum ,ky ( ! ,r4,a4,f4-#c4 ,! fact t ! ,l_/,d ratio ( ! ,r4,a4,f4-#c w+ is mu* great] at high lift co-effici5ts1 & l>ge angles ( incid5ce1 makes x v valuable z at ?is po9t ! great] ,l_/,d does n t5d to /all ! plane at sl[ spe$4 ,a l>ge ,l_/,d at great angles1 toge!r ) a wide /all+ angle t5ds = safety 9 sl[ spe$ fly+4 ,bo? w+ sections are /ructurally excell5t1 be+ v deep 9 ! region ( ! re> edge1 ! ,r4,a4,f4-#f be+ p>ticul>ly deep at ?is po9t4 ,a good deep sp> c be plac$ at almo/ any desirable po9t 9 ! ,r4,a4,f-#f1 & ! trail+ edge is deep en\gh to insure aga9/ rib weakness ev5 ) a comp>atively great ov]hang4 ,scale corrections = ! full size ,r4,a4,f4 w+s are v difficult to make4 ,accord+ to ! ,n4 ,p4 ,l4 reports1 ! correct$ value = ! maximum ,l_/,d ( ! ,r4,a4,f4-#c w+ is #ah4a1 ! model te/ indicat+ a maximum value ( #ae4f4 ,i believe t ,l_/,d #ag4e w\ld be a safe full size value = ?is section4 ,! same reports give ! full size ,l_/,d = ! ,r4,a4,f4-#f z #ah4e1 :i* w\ld be probably safe at #ah4j "u ! new conditions4 99,prop]ties ( ! ,eiffel ,sections 7#cb-cf-cg7994 ,?ree ( ! ,eiffel sections are %[n by ,figs4 #aj1 #aa & #ab1 ^! ,sections be+ select$ out ( an enorm\s numb] te/$ 9 ! ,eiffel laboratories4 ,!y diff] widely1 bo? a]odynamically & /ructurally1 f ! ,r4,a4,f4 a]ocurves j illu/rat$4 ,illu/ration3 ,fig4 #aj-aa-ab ,ord9ates = ,?ree ,eiffel ,w+ ,sections ,eiffel #cb is a v /able w+1 z has already be5 po9t$ out1 b ! value ( ! maximum ,l_/,d ratio is 9 d\bt z ?is quantity is v susceptible to *anges 9 ! w9d velocity--mu* m ?an 9 ! av]age w+4 ,s9ce ,eiffel's te/s 7 c>ri$ out at mu* high] velocity ?an at ! ,m4 ,i4 ,t41 8 lift-drift values at ! high] spe$s 7 naturally mu* bett] ?an ^? obta9$ by ! ,am]ican ,laboratory4 ,:5 te/$ at #fg4b miles p] h\r ! lift-drift ratio = ! ,eiffel #cb 0 #ahd :ile at #bb4d miles p] h\r1 ! ratio dropp$ to #ac4d4 ,?is te/ alone w give an idea z to ! v>iation possible ) *anges 9 scale & w9d velocity4 ,! foll[+ table gives ! results ( te/s c>ri$ out at ! ,massa*usetts laboratory1 report$ by ,alex&] ,klem9 & ,g4 ,m4 ,d5k+] 9 ,aviation & ,a]onautical ,eng9e]+4 ,w9d spe$1 #cj miles p] h\r4 ,! ,c4 ,p4 ,travel 9 ! ,eiffel w+ is v small1 z w be se5 f ,table #c4 ,at -#b ! ,c4 ,p4 is #j4cc ( ! *ord f ! lead+ edge & only moves back to #j4cgh at an angle ( #bj1 ! int]m$iate *anges be+ v gradual1 rea*+ a m9imum ( #j4cjd at #f incid5ce4 ,! maximum ,ky ( ,eiffel #cb is #j4jjbijh1 :ile = ! ,r4,a4,f4-#f w+1 ,ky #j4jjcjde maximum1 bo? co-effici5ts be+ a maximum at #af incid5ce1 b ! lift-drag at maximum ,ky is mu* bett] = ! ,r4,a4,f4-#f4 ,/ructurally1 ! ,eiffel #cb is at a disadvantage :5 comp>$ ) ! ,r4,a4,f4 sections s9ce x is v n>r[ at po9ts ne> ! trail+ edge4 ,?is w\ld necessitate mov+ ! re> sp> well up t[>d ! c5t] ) ! front sp> locat$ v ne> ! lead+ edge4 ,?is is ! type ( w+ us$ 9 a l>ge numb] ( ,g]man ma*9es4 ,x w also be not$ t !re is a v pron\nc$ rev]se curve or ,reflex 9 ! re> portion1 ! trail+ edge actually curv+ up f ! *ord l9e4 ,eiffel #cf is a mu* ?ick] w+ ?an ei!r ( ! o!r ,eiffel curves %[n1 & is defici5t 9 mo/ a]odynamical respects4 ,x has a l[ value = ,ky & a poor lift-drag ratio4 ,x has1 h[ev]1 be5 us$ on sev]al ,am]ican tra9+ ma*9es1 probably = ! reason t x p]mits ( /urdy con/ruction4 ,illu/ration3 ,fig4 #ac ,*>act]i/ic ,curves = ,eiffel ,w+s ,sections ,eiffel #cg is ess5tially a high-spe$ w+ hav+ a high ,l_/,d ratio & a small lift co-effici5t4 ,! maximum lift-drag ratio ( #bj4d is atta9$ at a negative angle -#jh4 ,! value ( ,ky at ?is po9t is #j4jjjhf1 an extremely l[ figure4 ,! maximum ,ky is #j4jjbhh at #ad4j1 ! ,l_/,d ratio be+ #d4j at ?is angle4 ,/ructurally x is ! wor/ w+ t we h yet discuss$1 be+ almo/ pap] ?9 = a consid]able di/ance ne> ! trail+ edge4 ,! "u surface is deeply camb]$1 ) ! maximum "u camb] ab\t "o-?ird f ! trail+ edge4 ,x is impossible to use ?is w+ )\t a v long ov]hang 9 ! re> ( ! section1 & l ! ,eiffel #cb1 ! front sp> mu/ be v f> =w>d4 ,= ^? desir+ flexible trail+ edges1 ?is is an ideal section4 ,?is w+ is be/ adapt$ = spe$ sc\ts & rac+ ma*9es because ( its great ,l_/,d1 b z its lift is small & ! c5t] ( pressure movem5t rapid at ! po9t ( maximum lift-drag1 x w\ld be necess>y to fly at a small range ( angles & l& at an extremely high spe$4 ,any slight *ange 9 ! angle ( incid5ce causes ! lift-drag ratio to drop at a rapid rate1 & h5ce ! w+ c\ld only be manipulat$ at its mo/ effici5t angle by an exp]i5c$ pilot4 ,aga91 ! angle ( maximum ,l_/,d is only a few degrees f ! angle ( no lift4 99,u4,s4,a4 ,w+ ,sections994 ,^! w+ sections 7 develop$ by ! ,aviation ,section ( ! ,signal ,corps1 ,unit$ ,/ates ,army1 & are decid$ improvem5ts on any w+ sections yet publi%$4 ,! six ,u4,s4,a4 w+s cov] a wide range ( application1 v>y+ z !y d1 f ! high spe$ sections to ! heavy lift w+s us$ on l>ge ma*9es4 ,! data 0 fir/ publi%$ by ,capta9s ,edg> ,s4 ,gorrell & ,h4 ,s4 ,m>t91 ,u4,s4,a41 by p]mission ( ,pr(essor ,c4 ,h4 ,peabody1 ,massa*usetts ,in/itute ( ,te*nology4 ,an ab/ract ( ! pap] by ,alex&] ,klem9 & ,t4 ,h4 ,huff 0 aft]w>ds pr9t$ 9 ,aviation & ,a]onautical ,eng9e]+4 ,:ile sev]al ( ! curves are modifications ( ! ,r4,a4,f4 sections already describ$1 !y are a]odynamically & /ructurally sup]ior to ! orig9als1 & especial att5tion is call$ to ! m>k$ /ructural advantages4 ,u4,s4,a4-#a & ,u4,s4,a4-#f are ess5tially high spe$ sections ) a v high lift-drag ratio1 ^! w+s be+ suitable = spe$ sc\ts or pursuit ma*9es4 ,! diff]5ce betwe5 ! w+s is v slight1 ,u4,s4,a4-#a ) ,k-#jjjcah giv+ a bett] l&+ spe$1 :ile ,u4,s4,a4-#f is slightly m effici5t at l[ angles & high spe$s4 ,illu/ration3 ,fig4 #ad4 ,u4,s4,a4 ,w+ ,sections ,nos4 #a-b-c-d-e-f1 ,%[+ ! ,ord9ates at ! ,v>i\s tations ,express$ z ,decimals ( ! ,*ord4 ,u4,s4,a4-#d is a ,heavy ,lift ,section1 ,:ile ,u4,s4,a4-#a & ,u4,s4,a4-#f4;are ,high ,spe$ ,w+s4 ,= ,any ,p>ticul> ,duty1 ! ,above ,w+s ,are ,v ,deep & ,p]mit ( ,l>ge ,/ructural ,memb]s4 ,! ,c5t] ( ,pressure ,movem5t ,is ,comp>atively ,slight4 ,) #j incid5ce1 ! ratio ( ,u4,s4,a-#aaa4j :ile ! lift-drag ( ,u4,s4,a4-#f at #j incid5ce is #ac4j4 ,! maximum lift ( ,u4,s4,a4-#a is sup]ior to t ( ,eiffel #cb1 & ! maximum lift-drag ratio at equal spe$s is f> sup]ior1 be+ #ag4h aga9/ #ad4ej ( ! ,eiffel #cb4 ,comp>$ ) ! ,eiffel #cb x w be se5 t ! ,u4,s4,a4 sections are f> bett] f a /ructural po9t ( view1 especially 9 ! case ( ,u4,s4,a4-#a4 ,! dep? 9 ! region ( ! re> sp> is exceptionally great1 ab\t ! same z t ( ! ,r4,a4,f4-#f4 ,:ile nei!r ( ! ,u4,s4,a4 w+s are z /able z ! ,eiffel #cb1 ! motion ( ! ,c4 ,p4 is n sudd5 nor ext5sive at ord9>y flight angles4 ,probably "o ( ! mo/ rem>kable ( ! ,unit$ ,/ates ,army w+s is ! ,u4,s4,a4-#d :i* has a high] maximum lift co-effici5t 7,ky7 ?an ev5 ! ,r4,a4,f4-#c4 ,! maximum ,ky ( ! ,u4,s4,a4-#d is #j4jjcfd comp>$ ) ! ,r4,a4,f4-#c 9 :i* ,ky 7,maximum7#j4jjcdha4 ,above #d incid5ce1 ! lift-drag ratio ( ! ,u4,s4,a4-#d is g5]ally bett] ?an t ( ! ,r4,a4,f4-#c1 ! maximum ,l_/,d at #d be+ consid]ably bett]4 ,?is is a mo/ excell5t w+ = a heavy seaplane or bomb]4 ,! ,u4,s4,a4-#b has an upp] surface simil> to t ( ! ,r4,a4,f4-#c1 b ! w+ has be5 ?ick5$ = /ructural reasons1 ?us caus+ a modification 9 ! l[] surface4 ,?is results 9 no p>ticul> a]odynamic loss & x is mu* bett] at po9ts ne> ! re> edge = ! reception ( a deep & effici5t re> sp>4 ,u4,s4,a4-#c is a modification ( ,u4,s4,a4-#b1 & l ,u4,s4,a4-#b w\ld fall "u ! head ( ,all ar\nd w+s1 a type simil>1 b sup]ior to ,r4,a4,f4-#f4 ,^! w+s are a compromise betwe5 ! high spe$ & heavy lift types--suitable = tra9+ s*ools or exhibition fly]s4 ,bo? h a fairly good ,l_/,d ratio & a correspond+ value = ,ky4 ,u4,s4,a4-#e has a v good maximum lift-drag ratio 7#af4ba7 & a good lift-drag ratio at ! maximum ,ky4 ,its maximum ,ky is sup]ior to all sections ) ! exception ( ,u4,s4,a4-#b & #d4 ,/ructurally x is v good1 be+ deep bo? =e & aft4 ,9 review ( ! ,u4,s4,a4 sections1 x may be said t !y are all rem>kable 9 hav+ a v heavy camb] on bo? ! upp] & l[] surfaces1 & at ! same "t are effici5t & /ructurally excell5t4 ,?is r contradicts ! usual belief t a heavy camb] w produce a l[ lift-drag ratio1 a belief t is also prov5 false by ! excell5t p]=mance ( ! ,eiffel #cg section4 ,! maximum ,ky is also well su/a9$ at & above #j4jjc4 ,!re is no %>p drop ( lift at ! ,/all+ angle & ! work+ range ( incid5ce is l>ge4 99,curtiss ,w+ & ,d\ble ,camb]$ ,sections994 ,an old type ( ,curtiss w+ is %[n by ,fig4 #ae4 ,x is v ?ick & an effici5t w+ = g5]al use4 ,x w be notic$ t !re is a slight reflex curve at ! trail+ edge ( ! "u surface & t !re is ample sp> room at almo/ any po9t along ! section4 ,! nose is v r\nd & ?ick = a w+ possess+ ! ,l_/,d *>act]i/ics exhibit$ 9 ! te/s4 ,! conditions ( ! te/ 7 ! same z = ! prec$+ w+ sections4 ,fig4 #af %[s a rem>kable ,curtiss section design$ = use z a /abiliz+ surface4 ,x is d\ble camb]$1 ! top surface be+ id5tical ) ! l[]1 & is !re=e non-lift+ ) ! *ord horizontal4 ,! =ce ex]t$ by ! surface is equal ) equal positive or negative angles ( incid5ce1 a valuable feature 9 a control surface4 ,9 spite ( its great ?ickness1 x is ( excell5t /ream l9e =m & !re=e has a v good lift-drag ratio4 ,at #j angle ( incid5ce ! resi/ance is at a m9imum1 & is mu* less ?an t ( a ?91 squ>e edg$1 flat plate4 ,?is d\ble camb]$ plane r$uces ! /ay brac+ & head resi/ance necess>y ) ! flat type ( /abiliz] surface4 ,illu/ration3 ,fig4 #ae4 ,old ,type ( ,curtiss ,w+4 #af4 ,curtiss ,d\ble ,camb] = ,control ,surfaces4 ,! ,curtiss sections m5tion$ above 7 describ$ 9 ,aviation & ,a]onautical ,eng9e]+ by ,dr4 ,j]ome ,c4 ,hunsak]1 b ! figures 9 ! above table 7 obta9$ by ! au?or on a slid+ te/ wire arrangem5t t has be5 "u developm5t = "s "t4 ,at ! "t ( writ+ sev]al ( ! ,u4,s4,a4 sections are "u inve/igation on ! same device4 ,,correction ,,factors ,,= ,,w+ ,,=m ,,& ,,size4 99,aspect ,ratio994 ,z previ\sly expla9$1 ! aspect ratio is ! relation ( ! span to ! *ord1 & ?is ratio has a consid]able effect ^u ! p]=mance ( a w+4 ,9 ! practical full size ma*9e ! aspect ratio may range f #e 9 monoplanes1 & small biplanes1 to #aj or #ab 9 ! l>g] biplanes4 ,! aspect 9 ! case ( triplanes is ev5 great]1 "s examples ( ! latt] hav+ aspects ( #af to #bj4 ,9 g5]al1 ! aspect ratio increases ) ! gross weight ( ! ma*9e4 ,control surfaces1 su* z ! rudd] & elevator1 usually h a mu* l[] aspect ratio ?an ! ma9 lift+ surfaces1 p>ticul>ly :5 flat non-lift+ control surfaces are us$4 ,! aspect ( elevator surfaces w range f unity to #c1 :ile ! v]tical rudd]s g5]ally h an aspect ( #a4 ,) a giv5 w+ area1 ! span increases directly ) an increase 9 ! aspect ratio4 ,! additional weight ( ! /ructural memb]s due to an increas$ span t5d to (fset ! a]odynamic advantages ga9$ by a l>ge aspect ratio1 & ! increas$ resi/ance due to ! numb] & size ( ! expos$ brac+ /ill fur!r r$uces ! advantage4 99,effects ( ,aspect ,ratio994 ,v>iations 9 ! aspect ratio d n give ! same results 9 all w+ sections1 & ! lift co-effici5t & ,l_/,d ratio *ange 9 a v irregul> mann] ) ! angle ( incid5ce4 ,! foll[+ tables give ! results obta9$ by ! ,n4 ,p4 ,l4 on a ,bl]iot w+ section1 ! aspect ratio be+ plott$ aga9/ ! angle ( incid5ce4 ,! figures are comp>ative1 an aspect factor ( unity 7#a1jjj7 be+ tak5 = an aspect ratio ( #f at ea* angle ( incid5ce4 ,to obta9 an approximation = any o!r w+ section at any o!r aspect ratio1 multiply ! model te/ 7,aspect#f7 by ! factor t corresponds to ! giv5 angle & aspect ratio4 ,at ! extreme "r ( ! table is a column ( r\gh av]ages1 tak5 )\t reg>d to ! angles4 ,! column ( av]age values is n ! av]age ( ! tabul> values b is ! av]age ( ! results obta9$ by a numb] ( inve/igators on diff]5t w+ sections4 ,?r\gh ! small angles ( #j & #b ! l[ aspect ratios give a maximum ,ky great] ?an ) ! l>g] aspects4 ,! l>g] aspects increase ! lift ?r\gh a l>g] range ( angles b h a l[] maximum value = ,ky at small angles4 ,beyond #b ! l>g] aspect ratios give a great] ,ky4 99,aspect = ,flat ,plates994 ,= flat plates ! results are diff]5t ?an ) camb]$ sections4 ,! lift-drag ratios are n mu* improv$ ) an increase 9 aspect1 b ! highe/ maximum lift is obta9$ ) a small aspect ratio4 ,= ?is reason1 a small aspect ratio %\ld be us$ :5 a high lift is to be obta9$ at l[ spe$s ) a flat plate z 9 ! case ( control surfaces4 ,an aspect ratio ( unity is satisfactory = flat v]tical rudd]s s9ce a maximum effect is desirable :5 taxi-+ ov] ! gr\nd at l[ spe$s4 ,! flat plate effects are n important except = control surfaces1 & ev5 9 ?is case ! plates are be+ sup]s$$ by d\ble camb]$ sections4 99,reason = ,aspect ,improvem5t994 ,! air fl[s lat]ally t[>d ! w+ tips caus+ a v decid$ drop 9 lift at ! out] ends ( ! w+s4 ,! lift-drag ratio is also r$uc$ at ?is po9t4 ,! c5t] ( pressure moves back ne> ! trail+ edge z we approa* ! tips1 ! maximum zone ( suction on ! upp] surface be+ also ne> ! trail+ edge4 ,! lift-drag ratio at ! c5t] ( ! plane is betwe5 #d or #e times t at a po9t ne> ! tips4 ,all ( ! desirable *>act]i/ics ( ! w+ are exhibit$ at a po9t ne> ! c5t]4 ,:5 ! aspect ratio is increas$1 ! ineffici5t tips =m a small] p]c5tage ( ! total w+ areas1 & h5ce ! losses at ! tips are ( less importance ?an w\ld be ! case ) a small aspect4 ,! end losses are n r$uc$ by end %ields or plates1 & 9 attempts to prev5t lat]al fl[ by curta9s1 ! losses are actually (t5 increas$4 ,prop] design ( ! =m ( ! w+ tip1 su* z rak+ ! tips1 or wa%+ out ! camb] & incid5ce1 c be reli$ ^u to increase ! lift factor4 ,?is *ange 9 ! tips causes ! ma9 w9d /ream to ent] ! w+s 9 a direction opposite to ! lat]al leakage fl[ & !re=e r$uces ! loss4 ,prop]ly rak$ tips may increase ! lift by #bj p] c5t4 99,effects ( ,scale 7,size & ,velocity7994 ,9 ! *apt] ,elem5t>y ,a]odynamics x 0 po9t$ out t ! lift ( a surface 0 obta9$ by ! motion ( ! air1 or ! turbul5ce caus$ by ! ent]+ ( ! plane4 ,x 0 also expla9$ t ! effect ( ! lift due to turbul5ce v>i$ z ! squ>e ( ! velocity & directly z ! area ( ! w+s4 ,?is w\ld indicate t ! lift ( a small w+ 7,model7 w\ld be 9 a fix$ proportion to a l>ge w+ ( ! same type4 ,?is holds true 9 practice s9ce ne>ly all laboratories h f\nd by exp]im5t t ! lift ( a l>ge w+ c\ld be comput$ directly f ! results obta9$ ) ! model )\t ! use ( correction factors4 ,t is to say1 t ! lift ( a l>ge w+ ) #dj times ! area ( ! model1 w\ld give #dj times ! lift ( ! model at ! same air spe$4 ,9 ! same way1 ! lift w\ld be proportional to ! squ>es ( ! velocities4 ,if ! span ( ! model is tak5 at #a feet1 & ! velocity z ,v feet p] second1 ! product ,,iv w\ld repres5t bo? ! model & ! full size ma*9e4 ,! lift is due to a]odynamic =ces /rictly1 & h5ce !re %\ld be no reason :y ! ,v law %\ld be int]f]$ ) 9 a *ange f ! model to ! full size ma*9e4 ,9 ! case ( drag ! conditions are diff]5t1 s9ce ! drag is produc$ by two factors t v>y at diff]5t rates4 ,"p ( ! drag is caus$ by turbul5ce or a]odynamic =ces & "p by sk9 friction1 ! =m] v>y+ z ,v :ile ! sk9 friction v>ies z ,v44 ,! a]odynamic drag v>ies directly ) ! area or span :ile ! sk9 friction "p ( ! drag v>ies z #a41 :]e #a is ! span4 ,f consid]ations ( ! span & ! spe$1 x w be se5 t ! frictional resi/ance increases mu* sl[] ?an ! a]odynamic resi/ance1 & consequ5tly ! l>ge ma*9e at high spe$ w\ld give less drag & a high] value ( ,l_/,d ?an ! small model4 ,9 o!r words1 ! results ( a model te/ mu/ be correct$ = drag & ! lift-drag ratio :5 appli$ to a full size ma*9e4 ,su* a correction factor is sometimes kn[n z ! ,scale factor4 ,eiffel gives ! correction factor z #a4jh1 t is ! liftdrag ratio ( ! full size ma*9e w be approximately #a4jh times z great z ! model4 ,a s]ies ( full size te/s 7 made by ! ,univ]sity ( ,/4 ,cyr 9 #aiab-aiac ) ! object ( comp>+ full size a]oplane w+s ) small scale models ( ! same w+ section4 ,! full size w+s 7 m\nt$ on an electric trolley c> & ! te/s 7 made 9 ! op5 air4 ,_m diff]5ces 7 not$ :5 ! small reproductions ( ! w+s 7 te/$ 9 ! w9d tunnel1 & no satisfactory conclusions c be arriv$ at f ^! te/s4 ,accord+ to ! !ory1 & ! te/s made by ! ,n4 ,p4 ,l41 ! lift-drag ratio %\ld increase ) ! size b ! ,/4 ,cyr te/s %[$ t ?is 0 n always ! case4 ,9 at lea/ ?ree ( ! te/s1 ! model %[$ bett] results ?an ! full size ma*9e4 ,!re seem$ to be no fix$ relation betwe5 ! results obta9$ by ! model & ! l>ge w+4 ,! c5t] ( pressure movem5t 0 always diff]5t 9 e comp>ison made4 ,"o cause ( su* pron\nc$ diff]5ce w\ld probably be expla9$ by ! diff]5ce 9 ! mat]ials us$ on ! model & full size w+1 ! model w+ be+ absolutely smoo? rigid wood :ile ! full size w+ 0 ( ! usual fabric con/ruction4 ,! fabric w\ld be likely to *ange 9 =m "u diff]5t conditions ( angle & spe$1 caus+ a great dep>ture f ! true values4 ,aga91 ! model be+ ( small size1 w\ld be a difficult object to ma*9e to ! exact outl9e4 ,a diff]5ce ( #a_/ajjj in* f ! true dim5sion w\ld make a great diff]5ce 9 ! results obta9$ ) a small surface4 99,plan ,=m994 ,w+s are made ne>ly rectangul> 9 =m1 ) ! ends m or less r\nd$1 & v little is n[ kn[n ab\t ! effect ( w+s v>y+ f ?is =m4 ,rak+ ! ends ( ! w+ tips at a slight angle increases bo? ! lift-drag & lift by ab\t #bj p] c5t1 ! angle ( ! rak$ end be+ ab\t #ae degrees4 ,rak+ is a widely adopt$ practice 9 ! ,unit$ ,/ates1 especially on l>ge ma*9es4 99,summ>y ( ,corrections994 ,we c n[ "w out ! total correction to be made on ! w9d tunnel te/s = a full size ma*9e ( any aspect ratio4 ,! lift co-effici5t %\ld be us$ z giv5 by ! model te/ data1 b ! corrections c be appli$ to ! lift-drag ratio & ! drag4 ,! scale factor is tak5 at #a4jh1 ! =m factor due to rake is #a4b1 & ! aspect correction is tak5 f ! =ego+ table4 ,! total correction factor w be ! product ( all ( ! individual factors4 99,example994 ,a c]ta9 w+ section has a lift-drag ratio ( #ae4jj1 z det]m9$ by a w9d tunnel te/ on a model1 ! aspect ( ! te/ plane be+ #f4 ,! full size w+ is to h an aspect ratio ( #h1 & ! w+ tips are to be rak$4 ,:at is ! correct$ lift-drag ratio ( ! full size ma*9e at #ad8 99,solution994 ,! total correction factor w be #a4jh #a4aj #ab #a4dci4 ,! lift-drag ratio ( ! full size modifi$ w+ becomes #ae4jj x #a4dci #ba4ehe4 ,z a comp>ison1 we w assume ! same w+ section ) rectangul> tips & an aspect ratio ( #c4 ,! total correction factor = ! new arrangem5t is n[ #a4jh ,x #j4gb #j4gggf :]e #j4gb is ! relative lift-drag due to an aspect ( #c4 ,! total lift-drag is n[ #ae4jj ,x #j4gggf #aa4ffd4 ,hav+ a l>ge aspect ratio & rak$ tips makes a v consid]able diff]5ce z w be se5 f ! above results1 ! rake & aspect ( #h mak+ ! diff]5ce betwe5 #ba4ehe & #aa4ffd 9 ! lift-drag4 ,area = area1 ! drag ( ! fir/ plane w be approximately "o-half ( ! drag due to an aspect ratio ( ?ree4 99,lift 9 ,slip ,/ream994 ,! portions ( a monoplane or tractor biplane ly+ 9 ! propell] slip /ream are subject$ to a mu* high] w9d velocity ?an ! outly+ p>ts ( ! w+4 ,s9ce ! lift is proportional to ! velocity squ>$1 x w be se5 t ! lift 9 ! slip /ream is f> high] ?an on ! surr\nd+ area4 ,assum+ = example1 t a c]ta9 propell] has a slip ( #cj p] c5t at a translational spe$ ( #hd miles p] h\r1 ! relative velocity ( ! slip /ream w be #hd_/j4gj #abj miles p] h\r4 ,assum+ a lift factor 7,ky7#j4jjbb1 ! lift 9 ! slip /ream w be ,l #j4jjbb #abj #abj #ca4fh p\nds p] squ>e foot4 ,9 ! translational w9d /ream ( #hd miles p] h\r1 ! lift becomes ,l #j4jjbb ,x #hd ,x #hd #ae4eb p\nds p] squ>e foot4 ,9 o!r words1 ! lift ( ! portion 9 ! slip /ream is ne>ly d\ble t ( ! re/ ( ! w+ ) a propell] effici5cy ( #gj p] c5t4 ,,*apt] ,,vii4 ,,biplanes ,,& ,,triplanes4 99,biplane ,*>act]i/ics994 ,f an a]odynamic /&po9t1 ! monoplane w+ is m effici5t ?an ! sup]pos$ w+s ( ! biplane type1 s9ce ! proximity ( ! two surfaces 9 ! latt] causes a decid$ loss 9 ! total lift4 ,o!r practical advantages1 h[ev]1 (fset ! losses due to ! sup]pos$ surfaces1 & h5ce ! total effici5cy ( ! complete biplane may be ev5 great] ?an t ( ! monoplane4 ,= ! same area ! /ructural p>ts ( ! biplane are light]1 & ?is advantage increases rapidly ) ! size ( ! ma*9e s t :5 a span ( #cf feet is exce$$1 any o!r arrangem5t ?an t ( ! biplane or triplane becomes almo/ a practical impossibility4 ,a biplane is easi] & *eap] to make ?an a monoplane1 s9ce ! w+ brac+ ( ! =m] c be arrang$ to bett] advantage1 ! load-be>+ memb]s c be simpl]1 & ! safety factor made high] = an equal weight4 ,by suitable adju/m5ts betwe5 ! w+s ( a biplane1 x is possible to obta9 a v high degree ( inh]5t longitud9al /ability )\t incurr+ mu* loss 9 effici5cy1 an arrangem5t t is ( c\rse impossible ) a s+le monoplane surface4 ,by /agg]+1 ! view ( ! pilot is increas$1 & ! g5]ally small] size ( ! ma*9e p]mits ( bett] maneuv]+ qualities = a giv5 load4 99,int]f]5ce994 ,due to int]f]5ce1 or to ! *ok+ ( ! air /ream betwe5 ! upp] & l[] surfaces1 ! lift ( bo? w+s is r$uc$1 ) ! drag rema9+ ab\t ! same z ) a s+le surface4 ,?is1 ( c\rse1 r$uces ! total lift-drag ratio at all except c]ta9 angles4 ,! relative lift-drag ratios ( ! monoplane & biplane dep5d to "s ext5t ^u ! =m ( ! w+4 ,int]f]5ce causes a loss on ! oppos+ faces ( ! w+s1 ! lift be+ r$uc$ on ! top surface ( ! l[] w+1 & on ! bottom surface ( ! top w+4 ,s9ce ! upp] surface ( ! l[] w+ is "u suction1 & !re=e produces ! great] proportion ( lift1 x is natural t ! l[] w+ lift %\ld be r$uc$ to a great] ext5t ?an 9 ! upp] w+1 s9ce x is only ! l[] surface ( ! latt] t is affect$4 ,at normal flight angles ! upp] w+ c>ries ab\t #ee p] c5t ( ! total load4 ,at z]o degrees incid5ce1 ! upp] w+ c>ries z high z #fb p] c5t ( ! total load1 :ile at #ab degrees ?is may be r$uc$ to #ed p] c5t4 99,gap-,*ord ,ratio994 ,call+ ! di/ance betwe5 ! upp] & l[] w+s ! gap1 x may be said t ! ratio ( ! gap to ! w+ *ord greatly influ5ces ! lift4 ,?is ratio is call$ ! gap-*ord ratio1 & may v>y f #j4h to #a4j 9 small ma*9es or #a4j to #a4b 9 sl[1 heavy a]oplanes4 ,) ! drag rema9+ practically con/ant1 ! lift-drag is ( c\rse affect$ by a *ange 9 ! gap-*ord ratio1 ?is quantity be+ dim9i%$ at small gap ratios4 ,comp>$ ) a monoplane1 ! lift ( a biplane is ab\t #j4gg :5 ! gap is #j4h ( ! *ord1 & ab\t #j4hi ( ! monoplane value :5 ! gap-*ord ratio is increas$ to #a4f4 ,9 ?is range ! lift-drag approximates #j4hb & #j4hi1 respectively4 ,! c5t] ( pressure movem5t is n greatly *ang$ ) any gap-*ord ratio1 & to all practical purposes rema9s ! same z ) ! monoplane4 ,x %\ld be und]/ood t ^! rem>ks apply only to ! ,or?ogonal biplane arrangem5t 9 :i* ! w+s are v]tically ov] "o ano!r4 ,:ile biplane effici5cy is increas$ by hav+ a l>ge gap-*ord ratio 7w+ effici5cy alone71 ! total effici5cy ( ! a]oplane is n always increas$ by a l>ge gap1 pr9cipally because ( ! great head resi/ance due to ! long] /ruts & int]plane brac+4 ,at high spe$s ! long] brac+ memb]s (t5 m ?an (fset ! ga9 due to w+ effici5cy1 & z a result ! gap ( high spe$ sc\ts w g5]ally be f\nd 9 ! neighborhood ( #j4h ! *ord4 ,) sl[1 heavy ma*9es1 :]e lift is ( great importance1 & :]e sl[ spe$ does n affect ! /ructural resi/ance to s great an ext5t1 ! gap-*ord ratio w range f #a4j to #a4b4 ,9 mak+ ! above comp>isons betwe5 monoplanes & biplanes1 equal aspect ratios h be5 assum$ = bo? types1 b 9 actual practice ! aspect ratio ( biplanes is always great] ?an ) monoplanes1 & z a result ! biplane loss is usually less ?an indicat$ above4 ,:5 correction has be5 made = ! aspect ratio1 ! disp>ity 9 ! monoplane & biplane values ( ,ky & ,l_/,d is n z great z commonly suppos$4 ,biplane r$uction factors1 or ! factors us$ 9 r$uc+ monoplane values to ^? ( ! biplane1 dep5d to a great ext5t ^u ! w+ section z well z ^u ! gap1 & = exact values ( ! factors we %\ld h ! te/s report ( ! w+s 9 biplane =m4 ,lack+ ?is in=mation1 we c adopt ! values obta9$ by ! ,n4 ,p4 ,l4 = an old type ( w+ 9 ord] to get approximate results4 ,to obta9 ! biplane values1 multiply ! monoplane values obta9$ by ! w9d tunnel te/ by ! factors f\nd "u ! requir$ gap-*ord ratio4 ,^! factors apply to an aspect ratio ( #f4 ,,biplane ,,r$uction ,,factors 7,n4 ,p4 ,l47 7,at ,normal ,flight ,angles7 ,gap-,*ord ,ratio4 #j4h #a4j #a4b #a4f ,ky ,r$uction ,factor #j4gg #j4hb #j4hf #j4hi ,l_/,d ,r$uction ,factor #j4hb #j4hd #j4he #j4hi ,dr4 ,hunsak] conduct$ exp]im5ts at ! ,massa*usetts ,in/itute ( ,te*nology on biplane & triplane comb9ations1 & ! results 7 report$ 9 ,aviation & ,a]onautical ,eng9e]+1 ,nov4 #a1 #aiaf4 ,! ,r4,a4,f4-#f section 0 us$ ) a gap-*ord ratio ( #a4b4 ,! biplane portions ( ! exp]im5ts are z foll[s1 ! actual ,ky & ,l_/,d values & r$uction factors be+ arrang$ accord+ to ! angle ( incid5ce3 ,x w be not$ t !re is /eady improvem5t 9 ! lift factor ) an increase 9 ! angle f #b up 7except at #h71 & t ! same holds true ) ! ,l_/,d factor4 ,t is1 ! biplane values become ne>ly monoplane values at high angles1 & 9 ! case ( ! ,l_/,d ratio ! biplane actually is #bd p] c5t great] ?an ! monoplane value at an angle ( #af4 ,! lift coeffici5t ,ky above1 is n f> f ! correspond+ ,ky1 = gap-*ord ratio #a4b 9 ! fir/ table4 ,! maximum biplane value ( ,l_/,d occurs at ! same po9t z 9 ! monoplane w+1 t is1 at #d4 ,! fact t ! lift-drag is s high at #af is v favorable1 s9ce ! biplane w\ld be less likely to /all :5 fly+ sl[ly1 & ) a big dem& on ! eng9e4 ,! range ( angles at ! /all+ angle is mu* great] ?an ) ! monoplane w+1 & ! lift does n fall (f s rapidly aft] ! maximum is rea*$4 99,biplane ,arrangem5ts994 ,9 ! =ego+ data we h assum$ t ! upp] w+ 0 plac$ directly above ! l[]1 & ) ! lead+ edges on ! same v]tical l9e z %[n by ,fig4 #c4 ,?is is kn[n z an ,or?ogonal biplane1 & ! gap is indicat$ by ,g & ! *ord by ,c4 ,9 ,fig4 #d ! =w>d edge ( ! top w+ is advanc$ beyond ! l[]1 or is ,/agg]$1 ! am\nt ( ! /agg] be+ indicat$ by ,s4 ,?is all[s ( bett] view1 & slightly increases bo? ! lift & ,l_/,d values4 ,) a comp>atively l>ge /agg] ! range ( ! /all+ angle is increas$1 & ! lift does n fall (f z rapidly aft] ! maximum is rea*$ z ) ! or?ogonal type4 ,9 ,fig4 #e ! top w+ is giv5 a backw>d /agg]1 b ! exact effects ( ?is arrangem5t are n g5]ally kn[n4 ,!re are few ma*9es us+ ! rev]s$ /agg]1 ! only example1 to ! writ]'s k1 be+ ! ,de ,havill& spe$ sc\t4 ,by /agg]+1 ! resi/ance ( ! int]plane brac+ /ruts 7#c7 is some:at r$uc$1 because ( _! incl9ation ) ! w9d1 al?\gh !y are long] = ! same gap ?an 9 ,fig4 #c4 ,fig4 #f %[s ! *ord ( ! l[] w+ 7,c'7 %ort] ?an ! upp] *ord1 a type us$ 9 ! ,nieuport spe$ sc\t4 ,9 effect1 ?is is a =m ( /agg]1 & x und\bt$ly wid5s ! view ( ! pilot1 & to "s ext5t increases ! effici5cy & ! range ( ! /all+ angle4 ,nei!r ! /agg] 9 7#d7 nor ! small l[] *ord alone improves ! /ability to any ext5t4 ,to obta9 any m>k$ advantage ) ! %ort l[] *ord1 ! *ord ,c' mu/ be v mu* %ort] ?an ! upp] *ord1 say f #j4hj;,c to #j4ej;,c4 ,! loss ( area is s great t ?is w\ld n be p]missible on any except ! fa/e/ ma*9es1 :]e lift is n a prim>y consid]ation4 ,! pilot's view1 h[ev]1 is v mu* improv$ ) ! %ort l[] *ord1 & 9 battle ?is is an important consid]ation4 ,fig4 #g %[s ! *ord ( ! upp] w+ incl9$ at an angle ) ! l[] *ord by ! am\nt 7d74 ,?is is kn[n z ,decalage & is productive ( a great degree ( longitud9al /ability :5 tak5 9 comb9ation ) /agg]4 ,! /ability atta9$ by decalage & /agg] is )\t a great loss 9 ! ,l_/,d ratio1 :ile ! lift & /all+ angle range are bo? increas$4 ,?is latt] /able comb9ation is %[n by ,fig4 #h1 9 :i* ! w+s are giv5 bo? /agg] & decalage4 ,illu/ration3 ,sl[ ,spe$1 ,two-,seat ,biplane1 ) a ,l>ge ,gap-,*ord ,ratio4 ,! ,l>ge ,gap ,is ,p]missible 9 a ,sl[ ,ma*9e1 z ! ,/rut ,resi/ance ,is ,less ,?an ! ,ga9 9 ,lift-,drag ,ratio ,obta9$ by ! ,great] ,gap4 ,x ,w ,be ,not$ ,t ,^! ,w+s ,h a ,consid]able ,am\nt ( ,/agg]4 ,! ,position ( ! ,bottom ,w+ ,all[s ! ,obs]v] to ,see ,almo/ ,directly ,bel[4 ,illu/ration3 ,a ,high ,spe$1 ,two-,seat ,fight+ ,biplane1 ) a ,small ,gap-,*ord ,ratio4 ,9 ,?is ,case1 ! ,/rut ,resi/ance ,w\ld ,be ,great] ,?an ! ,a]odynamic ,ga9 ( ! ,w+s ) a ,great] ,gap ,*ord ,ratio4 ,! ,gunn] ,is ,locat$ 9 ! ,re> ,seat1 & ,beh9d ! ,trail+ ,edge ( ! ,l[] ,w+s4 ,he ,has a ,cle> ,field to ! ,re> an ,ov] ! ,top ,w+4 99,=w>d ,/agg]994 ,eiffel p]=m$ exp]im5ts ) ,dor& w+s1 & f\nd t :5 ! top surface 0 /agg]$ =w>d by #a_/b4e ( ! *ord 7#j4d;,c71 & ) a gap-*ord ratio ( #j4i1 an increase 9 lift ( f #f to #aj p] c5t 0 obta9$4 ,! ,l_/,d 0 ! same z ) no /agg]4 ,) ?9 circul> plates1 #a_/ac4e camb]1 & a gap-*ord ratio #j4ff1 ! lift-drag 0 bett] 7?an ) no /agg]7 only :5 ! value ( ,ky 0 great] ?an #j4jff 7metric74 ,!n ! ,l_/,d improv$ progressively ) ! am\nt ( /agg]4 ,ky 0 improv$ by #e p] c5t :5 ! /agg] 0 equal to half ! *ord1 & by #aj p] c5t :5 ! /agg] 0 equal to ! *ord4 ,! ,n4 ,p4 ,l4 ) a ,bl]iot w+1 aspect ratio#d1 f\nd t ,ky 0 increas$ by #e to #f p] c5t ) a /agg] ( #j4d;,c1 & ! ,l_/,d 0 increas$ by ab\t #d p]c5t4 ,! gap-*ord ratio 0 #a4jj4 ,illu/ration3 ,a ,s+le ,seat ,biplane ,spe$ ,sc\t ) an ,air ,cool$ ,motor4 ,9 a s]ies ( te/s made by ,a4 ,t*]s*]sky1 ! backw>d /agg] z 9 ,fig4 #e gave ab\t #ae p] c5t great] lift ?an ! or?ogonal biplane1 or ab\t #d p] c5t less lift ?an a monoplane surface ( ! same area4 ,! /agg] 9 ?is exp]im5t 0 ab\t #j4cc;,c4 ,9 default ( m accurate in=mation1 x w\ld seem t backw>d /agg] w\ld give bett] results ?an =w>d /agg]1 s9ce ! air swept d[n by ! upp] surface w\ld pass fur!r to ! re> ( ! l[] plane & h5ce w\ld n s greatly affect ! vacuum on ! upp] surface ( ! l[] w+4 ,?is w\ld1 h[ev]1 de/roy ! view ( ! pilot to a great] ext5t ?an any ( ! o!r arrangem5ts4 ,/agg] always introduces /ructural difficulties1 makes ! w+s difficult to assemble1 & ! wires are ( v>y+ l5g?s4 ,a simple or?ogonal cell is m compact & bett] f a manufactur+ /&po9t1 z x simplifies ! fitt+s1 & to a slight ext5t decreases ! weight4 ,:5 comb9$ ) sweep back1 ! complication is p>ticul>ly 9 evid5ce4 ,x is pleas+ to note ! preval5ce ( or?ogonal cells on mod]n battle-planes4 99,influ5ce ( ,camb]994 ,! am\nt ( air swept d[n by ! upp] w+ is l>gely det]m9$ by ! curvature ( ! "u surface ( ! upp] w+4 ,by decreas+1 or flatt5+ out ! curvature ( ?is surface1 ! velocity is increas$ 9 a horizontal direction & r$uc$ 9 a v]tical direction1 s t ! l[] w+ is less affect$4 ,! upp] surface ( ! upp] w+ is n influ5c$ by int]f]5ce4 ,x %\ld be not$ at ?is po9t t air 9 /rik+ a convex surface is increas$ 9 horizontal spe$ :ile ! rev]se is true ( ! l[] concave surface4 ,if ! "u surface ( ! upp] w+ 7 made convex1 ! d[n tr5d ( ! air w\ld be /ill fur!r r$uc$1 & ! loss on ! l[] w+ r$uc$ 9 proportion4 ,increas+ ! camb] on ! upp] surface ( ! l[] w+ increases its horizontal velocity & h5ce affects ! upp] w+ to a less ext5t1 b z ! upp] w+ loss is comp>atively slight1 ! camb] increase bel[ is n ( great consequ5ce4 ,?is has only be5 tri$ 9 "o ma*9e to ! writ]'s k1 "o ( ! ,/&>d seaplanes1 9 :i* ! upp] w+ 0 an ,r4,a4,f4-#f & ! l[] w+ 0 a deeply camb]$ ,u4,s4,a4-#b section4 ,! l[] surface ( ! ,r4,a4,f4-#f is comp>atively flat4 99,effects ( ,decalage994 ,:5 ! upp] w+ incid5ce is increas$ 9 reg>d to t ( ! l[] w+1 or is giv5 decalage1 ! /ability is increas$ ) a slight increase 9 ! p[] or drag4 ,?is angle %[n by 7d7 9 ,figs4 #g & #h1 mu/ be accompani$ by /agg] to obta9 /ability1 ! angle 7d7 rang+ f #a to #d4 ,) a decalage ( #b4e1 & a /agg] ( half ! *ord1 a high degree ( /ability is atta9$ ) a loss 9 ! lift-drag ( f #d to #f p]c5t4 ,! lift & ! range ( ! /all+ angle are bo? increas$1 ! =m] by ab\t #c p]c5t1 :ile ! latt] is ne>ly d\ble4 ,by increas+ ! decalage to #d1 ! lift-drag is /ill #d p]c5t less ?an ) ! or?ogonal cell1 b ! range ( ! /all+ angle is ne>ly tripl$4 ,! #d decalage is v /able & is suitable = tra9+ ma*9es or = amateurs4 ,9 ei!r case1 ! /agg]-decalage sy/em is usually bett] ?an sweep back1 reflex curves or negative w+ tips4 ,)\t reg>d to ! /ability1 & only ) ! idea ( a great] ,l_/,d 9 m9d1 x has be5 usual 9 sev]al ,european ma*9es to adopt a negative decalage2 t is1 to increase ! angle ( ! l[] w+ 9 reg>d to ! upp] *ord4 ,) ! top *ord horizontal1 a negative decalage ( #d w\ld make ! incid5ce ( ! l[] w+ equal to #d4 ,?is has n be5 g5]ally f\nd advantage\s 9 model te/s1 b 9 full size ma*9es !re is a consid]able increase 9 ! ,l_/,d ratio4 ,! great] incid5ce ( ! l[] w+ also improves ! lift ( ?is surface & ?us requires less surface = obta9+ ! same total lift1 especially :5 top w+ is /agg]$ =w>d4 ,incid5ce ( top w+ ( ,nieuport #a-cj'4 ,l[] w+ is set at #c4 99,v>y+ ,incid5ce994 ,) sev]al types ( ,european spe$ sc\ts1 & 9 ! case ( ! old ,h&ley-,page monoplane1 ! angle ( incid5ce is r$uc$ f ! c5t] ( ! w+ to ! tip4 ,?us 9 "o spe$ sc\t1 ! incid5ce at ! body is #d1 & #b at ! tips4 ,a decrease 9 angle t[>d ! tips has mu* ! same effect z an increase 9 aspect ratio2 t is1 x decreases ! lat]al fl[ & end leakage4 ,x also has an effect 9 aid+ ! lat]al /ability because !re is less lift at ! tips1 & h5ce !y are less affect$ by side gu/s4 ,wa%$ out incid5ce is an aid to longitud9al /ability1 z ! c5t] ( pressure at ! tips is mov$ fur!r back ?an at ! c5t] ( ! w+1 & !re=e ! ,c4 ,p4 is di/ribut$ ov] a long] di/ance =e & aft ?an x w\ld be ) a uni=m angle ( incid5ce4 ,9 driv+ ! propell]1 ! motor t5ds to turn ! body 9 a direction opposite to t ( ! propell] rotation1 & if no o!r provision is made ?is mu/ be ov]come by means ( ! ail]ons4 ,! ,motor torque on small span ma*9es is p>ticul>ly difficult to ov]come 9 ?is way1 ow+ to ! %ort lev] arm l5g? ( ! ail]ons4 ,to practically ov]come ! torque1 )\t excessively load+ ! ail]ons1 x is usually ! practice to set ! l[] left w+ tip at a great] angle ?an ! l[] "r w+4 ,! great] angle at ! left gives a lift t opposes ! turn+ mom5t ( ! motor4 ,?is comp5sation c nev] be complete1 = ! motor torque v>ies ) ! motor output1 h5ce an av]age angle is select$ s t ! incid5ce w cov] ! usual horizontal flight spe$s4 99,triplane ,arrangem5t994 ,:5 a biplane exce$s a c]ta9 weight ! area requir$ = a giv5 l&+ spe$ makes x desirable to increase ! numb] ( lift+ surfaces to m ?an two1 if ! span & /ress are to be kept d[n )9 reasonable limits4 ,?us ! biplane has its limits z well z ! monoplane1 & 9 ! biplane ?is limit is g5]ally rea*$ :5 ! span approa*es #hj feet4 ,9 addition to ! increas$ weight due to spans ( ov] #hj feet1 !re are o!r tr\bles 9 reg>d to ! space requir$ = h\s+1 & awkw>dness 9 maneuv]+4 ,on ! small] & fa/] a]oplanes1 ! triplane arrangem5t p]mits ( space cond5sation1 & also all[s ( l>g] aspect ratios ?an ) ! biplane4 ,! great] dep? ( ! triplane /ructure makes ! int]plane brac+ ev5 m effective ?an 9 ! case ( ! biplane4 ,= equal spans !re is less brac+ expos$ to ! w9d1 & ! weight ( ! w+ sp>s & ribs c be consid]ably r$uc$4 ,! %ort] ribs ( ! triplane alone contribute 9 no small degree to ! sav+ 9 weight4 ,consid]+ ! w+s alone1 )\t ref]5ce to ! head resi/ance ( ! brac+1 etc41 !re is a great] loss ( lift & ,l_/,d :5 ?ree ti]s ( w+s are sup]pos$ ?an ) a biplane4 ,9 exp]im5ts by ,dr4 ,hunsak] ^u ,r4,a4,f4-#f & ,curtiss w+ sections1 x 0 f\nd t at ab\t #d1 t ! triplane requir$ ab\t #f p]c5t m p[] ?an ! correspond+ biplane4 ,at ?is angle1 ! ,l_/,d = ! triplane 0 #ab4h1 aga9/ ! ratio ( #ac4h = ! biplane4 ,! gap-*ord ratio 9 ea* case 0 ma9ta9$ at #a4b4 ,bo? ! ,r4,a4,f4-#f & ! ,curtiss w+s gave results ( ! same g5]al "*1 & !re 0 n a great deal ( diff]5ce 9 ! num]ical values4 ,at v high angles1 #ab to #af1 ! lift ( ! biplane & triplane only diff]$ by ab\t #b p]c5t1 b at v small angles su* z are us$ at normal flight spe$s1 ! r$uction ( lift 9 ! triplane 0 v m>k$4 ,! drag 0 n greatly diff]5t bel[ #ab1 b at #af ! drag-coeffici5t is less ?an t ( ei!r ! biplane or monoplane1 & = ma*9es fly+ at l[ spe$s1 or heavily load$1 ?is decrease is ( great advantage s9ce x relieves ! motor at a "t :5 p[] is p>ticul>ly requir$4 ,at ?is po9t x %\ld be not$ t at high angles1 ! ,l_/,d g5]ally is bett] = multiplanes 9 an almo/ direct proportion to ! numb] ( surfaces4 ,9 ?is exp]im5t1 ! lift-drag ratios = a monoplane1 biplane1 & triplane 7 respectively #d4e1 #e4f1 & #f4e4 ,! drop 9 lift aft] ! po9t ( maximum lift1 or ! /all+ angle1 is n z rapid z 9 ! case ( ! biplane or monoplane1 & h5ce !re is less dang] ( /all+ ! triplane4 ,) ! same area1 & load+1 ! l&+ spe$ ( ! biplane & triplane w be ab\t ! same4 ,! foll[+ tables give ! lift1 & lift-drag ratios z det]m9$ 9 ^! exp]im5ts1 ! factors be+ 9 t]ms ( ! monoplane values ( an ,r4,a4,f4-#f w+4 ,?us to obta9 triplane values1 multiply ! giv5 monoplane values by t numb] opposite ! requir$ angle ( incid5ce4 ,aspect ratio #f4 ,illu/ration3 ,curtiss ,triplane ,spe$ ,sc\t4 ,note ! ,great ,aspect ,ratio ( ! ,w+s1 & ! ,relatively ,great ,gap-,*ord4 ,ratio4 ,only ,"o ,set ( ,/ruts ,are ,us$ 9 a ,s+le ,r[1 ,h5ce ! ,head ,resi/ance ,is at a ,m9imum4 ,! ,span ,is #be'-j & ! ,*ord #b'-j1 ,giv+ an ,aspect ,ratio ( #ab4e4 ,?us1 if ! monoplane lift value = ! ,r4,a4,f4-#f w+ at #d is ,ky #j4jja4de1 !n ! triplane value w be #j4jjade #j4geg #j4jjajig z giv5 9 ! table4 ,! monoplane lift-coeffici5t ( any o!r w+ section c be h&l$ 9 ! same way ) fair accuracy4 ,to obta9 ! correct$ lift-drag ratio = any w+ section1 multiply ! lift-drag ( ! monoplane w+ by ! factor 9 ! above table correspond+ to ! incid5ce ( ! monoplane te/ w+4 ,illu/ration3 ,! ,italian ,caproni ,triplane ( ! ,heavy ,lift or ,bomb+ ,type4 ,motors ,are ,in/all$ 9 ,ea* ( ! ,?ree ,bodies1 ,tractor ,propell]s ,be+ ,us$ 9 ! ,two ,long ,out] ,bodies1 ,:ile a ,pu%] ,screw ,is ,us$ at ! ,re> ( ! ,c5tral ,pass5g] ,body4 ,! ,enorm\s ,size ( ,?is ,triplane ,c ,be ,se5 by ,comp>+ x ) ! ,caproni ,monoplane ,%[n at ! ,"r4 ,c\rtesy ,fly+4 ,! upp] w+ gives ! greate/ p]c5tage ( lift1 & ! middle w+ ! lea/1 s9ce ! latt] suff]s f int]f]5ce on bo? sides4 ,x has be5 f\nd t ! sum ( ! top & bottom w+s ( a triplane gr\p gives ! same lift z ! two w+s ( a biplane "u equal conditions4 ,x 0 also f\nd t ! lift-coeffici5ts & lift-drag ( ! upp] plane alone 0 v ne>ly equal to ! lift ( ! comb9$ effects ( all ?ree w+s1 & at all angles4 ,call+ ! lift ( ! middle w+ #a4jj 7#d71 ! lift ( ! upp] w+ w be #a4ia & ! l[] w+ #a4fd4 ,call+ ! ,l_/,d ( ! middle w+ #a4jj 7#d71 ! relative life-drag w be ,l_/,d #b4ei = ! upp] w+ & #a4fi = ! l[]4 ,) ! middle w+ /ill assum$ at unity1 ! lift ( ! top plane is at #a4di at #af1 & ! l[] w+ #a4bj4 ,! liftdrag at #af degrees w be respectively #a4jj1 #a4bb1 & #a4aag = middle top & bottom4 ,at #j1 ! upp] w+ w c>ry #b4fh1 ! middle #a4jj1 & ! bottom #a4hb4 ,at #j1 ! lift-drag ( ! top is #c4fc1 ! middle #a4jj1 & bottom #b4cj4 ,^! relative figures are only useful 9 comp>+ ! load+ :5 comput+ ! /r5g? ( ! /ructural p>ts4 ,see ,aviation & ,a]onautical ,eng9e]+ ,nov4 #a1 #aiaf4 99,ov]hang+ ,w+ ,tips994 ,9 _m ,am]ican ma*9es1 & 9 "s ,european ma*9es1 su* z ! ,f>man1 ! upp] w+ is giv5 a mu* great] span ?an ! l[]4 ,( late1 ! t5d5cy has be5 to make ! w+s ( equal1 span & fully #ij p] c5t ( ! mod]n ma*9es w be f\nd to be arrang$ 9 ?is way4 ,:ile ! ov]hang+ tips may slightly increase ! effici5cy ( ! biplane by r$uc+ int]f]5ce at ! ends1 x makes ! span unduly long & difficult to brace at ! end4 ,! add$ end brac+ due to ! ov]hang probably (fsets any a]odynamic advantage to be obta9$1 al?\gh ,i h no accurate data on ?is po9t4 ,compactness is c]ta9ly n a feature4 ,x is said t ail]ons are m effective :5 m\nt$ on ! upp] ov]hang1 & ?is may be s1 b ,i note t ! area is ab\t ! same 9 any case4 ,) ov]hang+ tips1 ! ail]ons are g5]ally plac$ on upp] w+s1 only :ile ) equal or ne>ly equal spans1 !y are plac$ top & bottom4 ,! ov]hang+ section & ! ail]ons =m a s+le deta*able unit z a g5]al rule4 ,) ne>ly equal spans1 ! upp] & l[] ail]ons are g5]ally int]connect$ ) a small /rut 9 su* a way t !y act toge!r4 ,small spe$ sc\ts1 r>ely if ev]1 h any ov]hang s9ce ! object ( ^! ma*9es is to make !m z small & compact z possible4 ,,*apt] ,,viii4 ,,effects ,,( ,,plan ,,=m4 7,,t&em ,,a]oplanes47 99,g5]al ,notes994 ,up to ! pres5t we h consid]$ only two w+ outl9es1 ! rectangul> & ! w+ ) rak$ tips4 ,9 addition1 we h consid]$ only ! effect tak+ place on monoplane surfaces4 ,= ! purpose ( obta9+ longitud9al /ability1 or = di/ribut+ ! lift ^u two or m foll[+ surfaces1 ! plan view 9 "s a]oplanes has be5 some:at modifi$ z 9 ! ,dunne1 ,langley & ,ago4 ,und\bt$ly ! simple rectangul> w+1 or ! w+ ) rak$ tips1 h prov$ ! mo/ effici5t f an a]odynamic /&po9t1 b z ! layman is usually int]e/$ 9 di/ort$ w+ %apes1 or odd-look+ outl9es1 ,i w describe ! effect ( su* /abiliz+ =ms ^u ! lift & drag4 ,figs4 #a-i %[ ! usual range ( w+ =ms1 at lea/ ^? t h be5 us$ on well kn[n ma*9es1 & all ( !m h fl[n ) v>y+ results4 ,9 any case1 ! v>iations 9 ! values ( ! lift & lift-drag are n excessive1 ! extreme cases v>y+ possibly n m ?an #bj p] c5t on ei!r side ( ! values = a pla9 rectangul> w+4 ,:ile almo/ p]fect longitud9al /ability c be obta9$ 9 o!r ways1 by less loss ?an by *ang+ ! plan =m1 c]ta9 manufactur]s /ill adh]e to "o or m deviations f ! m usual rectangul> =m4 ,fig4 #a %[s a plan view ( a ma*9e ) a rectangul> w+1 & ,no4 #b %[s ! ma*9e provid$ ) rak$ tips4 ,fig4 #c is a w+ ) an incl9$ ent]+ edge1 z us$ on ! ,engli% ,mann biplane4 ,fig4 #d is ! ,g]man ,ago ) a diamond =m surface1 ! evid5t purpose ( :i* is to simplify ! w+ sp> brac+ z %[n by ! dott$ l9es4 ,by br++ ! w+ sp>s 'toge!r at ! tips1 ! sp>s !mselves =m a triangle to resi/ ! drag /resses4 ,fig4 #e is ! common =m ( sweep back or retreat$ w+ z us$ 9 ! ,/&>d ,h-#c tra9+ biplane1 & sev]al o!r mod]n biplanes4 ,:ile ?is arrangem5t und\bt$ly assi/s longitud9al /ability1 x causes c]ta9 losses t w be describ$ lat]4 ,! inh]5tly /able ,dunne is %[n by ,fig4 #f 9 :i* ! sweep back is increas$ to almo/ #ij degrees4 ,9 fact ! retreat is s great t no tail or /abiliz+ surfaces are us$ at all1 ! elevator functions be+ p]=m$ by ! ail]ons4 ,x %\ld be not$ t ! swept back tips really act z /abiliz]s s9ce !y trail back f> beh9d ! c5t] ( gravity & c5t] ( pressure4 ,! ail]ons 7a7 are n ne$$ = lat]al balance1 h5ce asc5t & desc5t--& also turn+ 9 a horizontal plane--are p]=m$ by ! ail]ons 9 sett+ !m 9 diff]5t relative positions4 ,be+ f> to ! re> !y are v effective elevators1 al?\gh _! action & ! extreme retreat ( ! w+s1 causes a consid]able drag4 ,?is is some:at (fset by ! abs5ce ( tail resi/ance4 ,an ,au/rian or ,g]man ,taube is %[n by ,fig4 #g ) ! negative trail+ w+ tips 7a71 t greatly assi/ longitud9al /ability1 b :i* are decid$ly ineffici5t4 ,?is is evid5c$ by ! fact t nei!r ! ,g]mans nor ,au/rians build ?is ma*9e at pres5t--at lea/ = active s]vice4 ,! tips 7a7 are b5t up at ! re> & ?us =m a negative angle ( incid5ce ) ! ma9 lift+ surface4 ,?is 0 ! orig9al inv5tion ( ,igo ,etri*1 an ,au/rian1 & z ) ev]y?+ else1 ! idea 0 promptly grabb$ by ! ,g]mans at ! beg9n+ ( ! w> & claim$ z _! own idea4 ,etri* 0 "o ( ! pione]s 9 aviation1 a sci5ce t did n prosp] 9 ,g]many until ! impracticability ( ! ,zeppel9 = univ]sal s]vice 0 an accept$ fact4 ,illu/ration3 ,figs4 #a-i4 ,plan ,views ( ,diff]5t ,w+ ,arrangem5ts & ,w+ ,outl9es4 ,fig4 #h is ! w+ outl9e ( ! ,bl]iot monoplane1 a repres5tative w+ us$ on ! e>li] monoplanes4 ,?is is really rev]s$ rake1 & h5ce does n /& = effici5cy 9 lift4 ,a t&em a]oplane is %[n by ,fig4 #i 9 :i* ! lead+ surface is 7m7 & ! trail+ w+ is 7n74 ,! tail 7t7 may1 or may n be includ$4 ,?is is a type t has be5 neglect$ 9 its practical developm5t al?\gh x has be5 repeat$ly propos$4 ,! ,langley ma*9e1 ! ,montgom]y glid]1 & ! ,ri*>dson are ( ?is type4 ,9 all ! figures ! w+ ribs are indicat$ by ! ?9 full l9es pass+ across ! wid? ( ! w+1 ) ! tail at 7t74 ,! arr[ repres5ts ! l9e ( flight4 ,x w be not$ t ) any b rectangul> w+ outl9es ! rib l5g?s are diff]5t1 ?r\gh\t ! w+4 ,?is makes ?is w+ a bad manufactur+ proposition1 & a difficult & exp5sive w+ to repair4 ,to provide aga9/ em]g5cies ! aviator mu/ keep a complete extra w+ 9 res]ve = repair p>ts1 :ile ! manufactur] is put to ! exp5se ( a great numb] ( rib molds1 & mu/ also keep a l>ge numb] ( ribs 9 /ock4 ,!re is a con/ant difficulty due to ! fact t mi/akes are (t5 made 9 ord]+ ! ribs = repair1 & altoge!r1 any?+ b a rectangul> w+ is a decid$ nuisance4 99,sweep ,back or ,retreat994 ,) swept back w+s1 z %[n 9 ,fig4 #e1 ! c5t] ( pressure movem5t is peculi>4 ,! ,c4 ,p4 moves =w>d :5 r$uc+ ! incid5ce at small angles1 & ?us t5ds to r$uce head div+1 b at v l>ge angles ! ,c4 ,p4 aga9 moves =w>d1 t5d+ to increase ! angles fur!r & ?us /all ! ma*9e4 ,?is rev]sal ( ,c4 ,p4 movem5t takes place at ab\t #aj to #ab1 & ! movem5t is %>p] & fur!r ) ea* increase 9 ! sweep back4 ,at ord9>y angles ( flight1 say at f #j to #f ! =w>d ,c4 ,p4 movem5t is satisfactory1 b at l[ spe$s & high angles /ability is only p>tially secur$1 & h5ce = ! total p]=mance sweep back is n to be desir$4 ,! w+ section us$ 9 ! above inve/igation 0 an ,r4,a4,f4-#f ) an aspect ratio ( #f4 ,9 reg>d to ! lift coeffici5t ,ky1 x 0 not$ t ?is factor 0 decreas$ ) e degree 9 ! angle ( sweep back4 ,at ! incid5ce angle ( #d = ! maximum value ( ,l_/,d1 ! value ( ,ky decreas$ f #j4jjadc ) a sweep back ( #j 7,/raight w+s71 to #j4jjabj ) a sweep back ( #cj4 ,at ! same incid5ce1 b ) a sweep back ( #aj1 ! lift became3 ,ky #j4jjacj4 ,) a retreat ( #bj1 ,ky- #j4jjabi4 ,! lift-drag also suff]$ ) an increase 9 retreat1 ?is be+ #ag4jj ) /raight w+s1 at #af4e at #aj1 #af4b at #bj1 & #ab4h at #cj4 ,up to1 & includ+ a retreat ( #bj1 ! loss 9 lift-drag is n s bad1 b 9 ! *ange f #bj to #cj !re is a v great loss4 ,illu/ration3 ,fig4 #aj4 7,upp]7 ,v>i\s ,angles ,made by ,w+s ,dur+ ,exp]im5ts4 7,bel[7 ,! ,c5t] ( ,pressure ,movem5t ) ,v>y+ ,angles4 ,! angle ( retreat h]e9 specifi$ is su* t ea* w+ is mov$ back ?r\gh an angle ( "o-half ! total giv5 retreat 7r7 angle 9 ,fig4 #e4 ,t is1 ) a retreat ( #cj1 ea* w+ section makes an angle ( #ae ) ! ent]+ edge ( a pair ( /raight w+s4 ,x is m usual to specify ! includ$ angle betwe5 ! lead+ edges z indicat$ by 7,s7 9 ,fig4 #e4 ,9 ! upp] portion ( ,fig4 #aj is %[n ! v>i\s angles ( ! w+s dur+ ! exp]im5ts1 :ile bel[ is ! ,c4 ,p4 movem5t accord+ to ! diff]5t angles ( retreat4 ,! above is bas$ on exp]im5ts made by ,h4 ,e4 ,rossell & ,c4 ,l4 ,br&1 assi/ant ,naval ,con/ructors1 ,u4 ,s4 ,navy1 & publi%$ 9 ,a]ial ,age4 ,! c5t] ( pressure ref]r$ to is t at ! =w>d po9t ( ! middle longitud9al section ( ea* w+1 & ) a giv5 incid5ce ! ,c4 ,p4 is ?r[n to ! re> by ab\t #j4b ( ! *ord by a sweep back ( #aj degrees1 & #j4d ( ! *ord = a sweep back ( #bj4 ,! c5t] ( gravity ( ! ma*9e w ?us h to be mov$ to ! re> if sweep back is employ$4 ,9 mak+ a turn a ma*9e ) sweep back has a natural t5d5cy to bank up 9 ! correct attitude1 & ev5 a retreat ( #aj w add ne>ly #ajj p] c5t to ! bank+ t5d5cy :5 comp>$ to a pair ( /raight w+s4 ,x w be se5 t ) swept back w+s1 ! lead+ edge is radial1 consequ5tly meets ! air /ream at m ne>ly a "r angle4 ,?is gives m lift to ! out] w+ ?an w\ld be ! case ) /raight ent]+ edges1 :ile ! inn] end losses increase correspond+ly 9 lift & h5ce t5ds fur!r to depress ! inn] tip4 ,! greate/ value ( sweep back is f\nd 9 its resi/ance to side slip4 ,if ! ma*9e %\ld be ov] bank$1 & t5d to slip d[n t[>d ! inn] side ( ! turn1 ! backw>d angle ( ! inn] w+s w cause ! ent]+ edge to meet ! side /ream at m ne>ly "r angles1 & ?us t5d to r$uce ! bank & ! inn] slide slip4 ,9 ?is respect ! retreat is an aid to lat]al /ability4 ,on ! o!r h&1 ! sweep back t5ds to keep ! ma*9e roll+ 9 r\gh wea!r = side gu/s !n meet ! incl9$ w+ edges at an effective angle4 ,?is is p>ticul>ly noticeable 9 l&+4 99,rak$ ,tips994 ,?is subject 0 discuss$ "u ,/&>d ,w+ ,section1 b x may be repeat$ "h1 t ,eiffel 9 an exp]im5t ) ! ,co&a ,w+ 7,eiffel #ch71 f\nd t ! ,l_/,d ( ! rak$ w+ 0 #bj p] c5t high] ?an ) ! same w+ 9 rectangul> =m4 ,?is value w\ld n be safe to assume ) all sections4 ,illu/ration3 ,fig4 #aa4 ,influ5ce ( ,wa% ,d[n on ! ,re> ,w+s ( a ,t&em ,pair4 ,illu/ration3 ,fig4 #ab4 ,t&em ,arrangem5ts ,us$ 9 ,eiffel ,exp]im5ts4 7#a7 ,*ords 9 ,/raight ,l9e1 7#b7 ,re> ,w+ at #b4e1 7#c7 ,re> ,w+ at #e4 99,t&em ,arrangem5t994 ,9 t&em w+s z %[n by ,fig4 #i1 ! d[nw>d wa% ( ! front w+ 7m7 w affect ! re> w+ 7n7 by caus+ a *ange 9 ! relative direction ( ! fl[4 ,if ! front w+s are at an incid5ce ( 7i7 degrees 7,fig4 #aa71 ! deviation or wa%d[n ( ! air /ream to ! re> w be express$ by3 d 7#j4e;i #a74 ,if i incid5ce ( re> w+ measur$ f ! *ord ( ! front w+1 !n ! angle ( incid5ce made by ! re> *ord to ! horizontal w be3 ,i 7i-i'7 - 7#j4e;i #a71 :]e ,i is ! incid5ce ( ! re> plane ) ! horizontal4 ,exp]im5ts by ,eiffel on t&em planes ) circul> camb]$ a](oils gave exce$+ly good results = c]ta9 comb9ations 7,fig4 #ab74 ,^! arrangem5ts 7 us$1 7#a7 ,*ords 9 a /raight l9e 7#b71 ,re> a](oil tilt$ d[n at a negative angle ( #b4e1 7#c71 ,re> ,plane tilt$ d[n at a negative angle ( #e4 ,9 all cases ! camb] 0 #a_/ac4e ( ! *ord1 & ! front & re> w+s 7 spac$ two *ord wid?s ap>t4 ,:ile ! drag did n *ange mu* = any ( ! arrangem5ts1 ! lifts v>i$ widely1 & arrangem5t 7#b7 is by f> ! m effici5t 9 lift+ capacity4 ,no4 #b is #ej p] c5t great] ?an 7#a71 & has twice ! lift+ ability ( 7#c74 ,= ! same angle ( incid5ce1 ! front w+ does ! same am\nt ( lift+ 9 all cases1 ! diff]5ce be+ entirely due to ! *anges 9 ! re> surface4 ,9 7#b7 ! lift ( ! re> a](oil is actually #ac p] c5t great] ?an ! front plane4 ,! foll[+ tables give ! results3 ,demo ,table ,,table ,,( ,,lifts ,,9 ,,grams ,,= ,,?ree ,,arrangem5ts4 ,,angle ,,( ,,arrangem5t ,,arrangem5t ,,arrangem5t ,,incid5ce 7#a7 7#b7 7#c7 #c #ffe #ajid #ccd #f #ihg #aefh #gjc #i #acae #bjfh #ife #ab #aedj #bcbf #acdg ,av]age at all #aabg #agfd #hcg angles ,p]c5tage #j4fd #a4jj #j4dg ,illu/ration3 ,fig4 #ac4 ,drzewiecki ,t&em ,arrangem5t = ,longitud9al ,/ability4 ,! lifts 9 ! above table are = ! two planes work+ toge!r1 & ! angle ( incid5ce is ! angle ( ! front a](oil1 or r ! angle ( ! comb9ation4 ,! w+s 7 #ae x #ij c5timet]s1 aspect ratio #f4 ,fig4 #ab %[s ! con/ruction cle>ly4 ,?is is only true = circul> ar*$ surfaces ( ! camb] giv54 ,illu/ration3 ,fig4 #ad4 ,drzwiecki ,t&em ,w+ ,arrangem5t = ,/ability4 ,m4 ,drzewiecki work+ ) ,eiffel's results on ! above comb9ations1 produc$ an inh]5tly /able t&em monoplane1 9 :i* ! front & re> w+s 7 ( diff]5t camb]s & 7 set at diff]5t incid5ces4 ,! front w+ is ,eiffel ,no4 #h set normally at #h incid5ce1 & ! re> w+ is ,eiffel ,no4 #ac-;bis 7,bl]iot #aa-;bis71 set normally at #e4 ,! c5t] ( gravity is approximately half-way betwe5 ! two w+s1 & ! front is small] ?an ! trail+ surface4 ,because ( ! diff]5ce 9 area1 ! lift ( ! front w+ v>ies less rapidly ?an ! re> :5 ! angle ( ! ma*9e *anges because ( di/urb$ air4 ,%\ld ! ma*9e head up1 ! re> w+ increases fa/] 9 lift ?an ! front1 & h5ce re/ores ! ma*9e to a horizontal position4 ,%\ld ! front surface drop1 ! incid5ce is r$uc$1 b z incid5ce ( ! re> w+ is less ?an ! front 7#h71 ! re> w+ is r$uc$ to ne>ly a z]o angle ( incid5ce--7,) little lift74 ,! front w+ is /ill incl9$ at a consid]able incid5ce3 7#c7 :5 ! re> is at z]o4 ,?is drops ! re>1 & raises ! front w+ s t ! normal attitude is re/or$4 ,lat]al /ability is obta9$ by mov+ ! two halves ( ! front w+ 9 relation to "o ano!r1 ! relative movem5t be+ simil> to t ( ail]ons4 ,illu/ration3 ,typical ,w+ ,assembl+ ,%op ,,*apt] ,,ix4 ,,w+ ,,con/ruction4 99,g5]al ,w+ ,frame ,lay\t994 ,9 _m ways1 ! frame ( ! w+ is "o ( ! mo/ important /ructural p>ts ( ! a]oplane4 ,x n only ma9ta9s ! prop] a]odynamic =m ( ! a](oil1 b also transmits ! air pressure & lift to ! body ( ! ma*9e1 & !re=e c>ries ! entire weight ( ! a]oplane :5 9 flight4 ,9 spite ( ! heavy load+ on ?is frame x has be5 br\ght to a rem>kable degree ( /r5g? & lightness4 ,n only is ,brute /r5g? necess>y1 b x mu/ also be rigid en\gh to prop]ly reta9 ! outl9es ( ! a](oil ) ! heavie/ load+s1 h5ce ! effici5cy ( ! a]oplane greatly dep5ds ^u ! /iffness z well z /r5g?4 ,! cont\r ( ! ent]+ edge mu/ be p>ticul>ly accurate & well support$ s9ce x is at ?is po9t t ! great] "p ( ! lift is obta9$1 & :]e a slight deviation 9 =m w mat]ially affect ! lift & drag4 ,! fabric surface1 on :i* ! air pressure is ex]t$1 mu/ transmit ! pressure & lift to ! ma9 /ructural memb]s ?r\gh ! p>ts t give =m to ! surface4 ,! fabric surfac+1 be+ flexible & pliant1 mu/ be support$ at frequ5t int]vals by ! =m+ memb]s :i* 9 effect are simil> to ! joi/s ( a floor sy/em4 ,! =m+ memb]s are !n support$ 9 turn by longitud9al beams1 or gird]s1 t transmit ! pressure to ! po9t :]e ! load is appli$4 ,! gird]s n only c>ry ! lift+ =ce1 b mu/ also take c>e ( ! drag :i* acts at "r angles to ! lift4 ,to pass gird]s t are suffici5tly /rong1 & yet )9 ! limits ( weight1 ?r\gh ! n>r[ space betwe5 ! top & bottom surfaces ( ! w+ is n always ! simple/ ( problems4 ,figs4 #a & #b %[ typical w+ frames 9 diagrammatic =m1 ! upp] views are ! plans1 :ile at ! bottom are sections tak5 ?r\gh ! w+4 ,! outl9es ( ! sections are curv$ to ! outl9es ( ! a](oil adopt$ = ! w+s1 & aft] ?is outl9e is drawn out to scale1 we mu/ maneuv] our /ructural memb]s s t !y w lie entirely betwe5 ! surfaces4 ,9 ,fig4 #a1 ! =m+ ribs are indicat$ by ,r1 ^! be+ ! memb]s curv$ to ! a](oil =m4 ,!y are spac$ along ! l5g? ( ! w+ at int]vals ( ab\t "o foot & ! fabric is appli$ to ! top & bottom edges ( ! rib4 ,! ribs are fa/5$ to ! front sp> ,f1 & ! re> sp> ,s4 ,! sp>s are equival5t to beams1 & are = ! purpose ( transmitt+ ! lift ( ! ribs to ! body4 ,a ?9 /rip ,e 7nos+7 runn+ along ! ent]+ edge ( ! w+1 s]ves to hold ! fabric taut at ?is po9t & also =ms x to ! %ape ( ! a](oil ent]+ edge4 ,! ?9 trail+ edge /rip 7,t7 p]=ms ! same purpose1 & ! w+ outl9e is complet$ by ! ,end b[ 7,a7 :i* reta9s ! fabric at ! w+ tips4 ,betwe5 ! front sp> ,f & ! re> sp> ,s is ! truss$ ,drag brac+1 :i* b9ds ! two sp>s into a truss 9 a horizontal direction1 & aga9/ ! drag ( ! surfaces4 ,?is consi/s ( ! ,drag wires or cables 7d7 & ! %ort wood /ruts 7e71 al?\gh 9 _m cases ! ribs are /r5g!n$ at ! po9t ( atta*m5t ( ! drag wires & s]ve z /ruts4 ,! ail]on ,g is locat$ at ! out] tip & is h+$ to ! re> sp> or to an ext5sion ( ! re> sp>4 ,betwe5 ! sp>s are ?9 /rips kn[n z batt5s :i* /iff5 ! ribs sideways1 ^! are %[n by 7,f74 ,illu/ration3 ,fig4 #a4 7,left7 ,w+ ,assembly ) ,sp> to ! ,re> ( ! ,ent]+ ,edge4 ,fig4 #b4 7,"r7 ,assembly ) ! ,front ,sp> at ! ,ent]+ ,edge4 ,metal connection clips ,c1 at ! end ( ! w+ sp>s1 are = atta*+ ! w+s to ! body1 or = connection ( ! two halves ( ! upp] w+ ( a biplane4 ,look+ at ! l[] sectional view we see ! int]plane /ruts ( a biplane atta*$ to ! front & re> sp>s z at 7m7 & 7n74 ,ref]r+ to ! plan view1 ! location ( ! /ruts is indicat$ by 99 99 99 at ! po9ts :]e ! drag-brac+ is atta*$ to ! sp>s4 ,fig4 #b is a =m ( w+ 9 :i* ! sp> ,f' also =ms ! ent]+ edge1 ?us elim9at+ "o "p ( ! w+4 ,"o objection to ?is con/ruction is t ! front sp> mu/ necess>ily be %all[] ?an ! sp> %[n 9 ,fig4 #a4 ,! re> sp> is 9 ! usual location at ,s'1 ! two sp>s be+ connect$ ?r\gh ! usual end b[ ,a'4 ,! trail+ edge ,t' may be ei!r a ?9 /rip1 or x may be a ?9 cable z indicat$4 ,?is w+ is simil> to ! w+ us$ on ! e>ly ,wright ma*9es1 & is /ill us$ by ,f>man1 ,vois9 & o!r ,european manufactur]s ( biplanes4 ,usually ! trail+ ends ( ! ribs ov]hang ! re> sp> = q a di/ance1 9 ?is type ( w+1 giv+ a flexible trail+ edge4 ,! front & re> int]plane /ruts 7m7 & 7n7 are %[n1 ! =m] connect+ ) ! front sp> at a po9t ne> ! ent]+ edge4 ,illu/ration3 ,fig4 #c4 ,sub-,rib ,con/ruction1 ! ,sub-,ribs 7r7 ,are ,plac$ at ! ,ent]+ ,edge4 ,fig4 #c %[s ! usual con/ruction except t %ort ,sub-ribs m>k$ 7r7 are plac$ betwe5 ! ma9 ribs ,r at ! ent]+ edge4 ,^! %ort ribs increase ! support & accuracy ( ! curve at ! ent]+ edge1 or else all[ wid] spac+ ( ! ma9 ribs ,r4 ,! fabric mu/ be well support$ at ?is po9t1 n only to ma9ta9 ! be/ effici5cy ( ! a](oil1 b to relieve ! /ress on ! fabric1 z x is "h 7,top surface7 t ! greate/ suction pressure comes4 ,%\ld !re be a rip or te> ne> ! ent]+ edge1 9 ! l[] surface1 ! upp] fabric w be subject$ to bo? ! pressure und]nea? & ! vacuum above4 ,?is adds fully #be p] c5t to ! load on ! upp] fac+4 ,! ma9 sp>s may be ( wood or /eel tub+1 al?\gh ! =m] mat]ial is g5]ally us$4 ,!y are ( a v>iety ( =ms1 ! ,i beam section1 solid rectangul>1 holl[ box1 or a comb9ation ( plate & ,i sections1 ! total object be+ to obta9 ! greate/ /r5g? ) ! lea/ possible weight4 ,:5 made up ( sev]al pieces ( wood !y are kn[n z ,built up sp>s4 ,illu/ration3 ,fig4 #d4 ,effects ( ,c4,p4 ,movem5t on ,sp> ,load+ ,! load on ! sp>s v>ies ) ! total weight c>ri$1 & also ) ! movem5t ( ! c5t] ( pressure due to *anges 9 ! angle ( incid5ce4 ,:5 ! c5t] ( pressure moves to any ext5t1 ! loads on ! two sp>s may v>y betwe5 wide limits1 & 9 extreme cases1 ei!r sp> may c>ry ! full load4 ,?is is %[n cle>ly by ,fig4 #d1 a section tak5 ?r\gh ! w+4 ,! front sp> ,f & ! re> sp> ,s are spac$ by ! di/ance ,l1 ! respective sp> loads be+ indicat$ by ,y & ,z4 ,z be=e expla9$1 ! c5t] ( pressure moves =w>d at l>ge angles 7,,cp71 :ile at small angles x moves back say to position 7,,cp'74 ,%\ld x move back z f> z ,,cp-#b1 ! load w come directly "u ! re> sp> & ?is memb] w !re=e c>ry ! entire load4 ,:5 at ! =w>d position ,,cp1 ! great] "p ( ! load w come on ! front sp>1 & only a small portion w n[ come on ,s4 ,9 ! same way1 :5 at a small angle ( incid5ce1 ! c5t] ( pressure w be at ,,cp'1 a di/ance 7,k7 f ! re> sp>4 ,! great] "p ( ! load w n[ be on ,s4 ,! action is ! same z if ! entire weight ,w or lift1 7 conc5trat$ at ! c5t] ( pressure4 ,:5 int]m$iate betwe5 ! two sp>s1 ! c5t] ( pressure causes a b5d+ mom5t 9 ! rib ,r1 & is at a maximum :5 ! ,,cp is midway betwe5 ! two sp>s4 ,x w be se5 t ! ,c4 ,p4 movem5t has an important effect outside ( ! "q ( /ability1 & ?is travel mu/ be tak5 into c>eful consid]ation :5 ! /r5g? ( ! sp>s is calculat$4 ,to f9d ! load on ! re> sp>1 = example1 ) ! c5t] ( pressure at ,,cp1 multiply ! lift ,w by ! di/ance ,p1 & divide by ! sp> spac+ ,l4 ,?is w give ! load ,z4 ,) ! ,c4 ,p4 9 ! same position1 ! load on ! front sp> w be ! diff]5ce betwe5 ! total lift ,w & ! load on ! re> sp>1 or ,y ,w-,z4 ,) ! load at ,,cp'1 ! load on ! front sp> w be3 ,y ,wx,k_/,l1 & ! load on ,s w be ,z ,w - ,y4 ,= example1 we w assume t ! lift ,w #ajjj p\nds1 & ! di/ance ,p #ab in*es4 ,! sp> spac+ ,l #cj in*es & ! c5t] pressure is at ,,cp4 ,! load ,z on ! re> sp>1 w be3 ,z ,wx,p_/,l #ajjj x #ab_/cj #djj p\nds4 ,! load on ! front sp> c be f\nd f ! =mula1 ,y ,w - ,z #ajjj-djj #fjj p\nds4 ,illu/ration3 ,fig4 #e4 ,p]spective ,view ( ,w+ ,con/ruction 7,re> ,sp> ,omitt$71 ,%[+ ,holl[$ ,ent]+ ,edge & ,built-,up ,sp>4 ,rib ,is ( ! ,i ,beam ,type4 ,c\rtesy ,flight4 ,fig4 #e4 %[s a typical =m ( w+ con/ruction 7re> sp> omitt$74 ,! front sp> is ( ! ,built up type1 & ! trail+ edge is a flatt5$ /eel tube4 ,! re> sp> is simply a solid rectangul> beam4 ,a c5tral a% ,i beam is us$ z ! front sp>1 ) v]tical spruce plates on ei!r side4 ,! spruce ent]+ edge1 or nos+1 is =m$ to ! %ape ( ! ent]+ edge & is holl[$ out = lightness4 ,! rib is also ( ! built up type1 ! upp] & l[] flanges are ( spruce & ! middle portion 7,web7 is cotton-wood4 ,at ! po9t :]e ! sp> passes ?r\gh ! rib1 ! rib flanges pass ov]1 & are tack$ to ! sp>4 ,! spruce nos+ fits closely ov] ! front web ( ! rib4 ,! rib flanges are cut away s t ! outside ( ! nos+ w come flu% ) ! flange l9e ( ! rib4 ,illu/ration3 ,fig4 #f4 ,caudron ,monoplane ,w+ ) ,/eel ,tube ,sp>s & ,flexible ,trail+ ,edge4 ,a ,slot 9 ! ,re> ( ! ,rib ,web ,p]mits ! ,deflection ( ! ,trail+ ,edge4 ,drag ,wire ,brac+ ,is ,us$ ,betwe5 ! ,front & ,re> ,sp>s4 ,c\rtesy ,flight4 ,a w+ ( decid$ly diff]5t con/ruction is ! ,caudron monoplane w+ %[n by ,fig4 #f1 ! front & re> sp>s ( ?is w+ be+ /eel tubes ) an ent]+ edge ( ?9 wood4 ,! drag brac+ wires may be se5 connect$ at alt]nate ribs by small /eel plates & ! latt] also s]ve to atta* ! ribs to ! sp>s4 ,in/ead ( be+ cut out entirely1 ! webs ( ! ribs are holl[$ out betwe5 ! sp>s4 ,probably ! mo/ unique feature is ! con/ruction ( ! long flexible trail+ ends ( ! rib at ! "r4 ,! trail+ rib edge is divid$ into an upp] & l[] section by a long slot1 ! upp] sections be+ rigid1 :ile ! l[] edge is ?9 & flexible4 ,! flexible edges all[ ! l[] ends ( ! ribs to give locally1 & r$uce ! camb] :5 /ruck by a heavy gu/4 ,?is aids 9 ! lat]al /ability1 s9ce ! lift is ?us consid]ably r$uc$ at ! po9t ( impact1 & x also relieves ! w+ ( unnecess>y /resses4 ,! rigid upp] section ( ! rib acts z a limit /op to ! l[] half1 & prev5ts ! flexure f exce$+ a c]ta9 am\nt4 ,ow+ to ! flexibility ( ! trail+ edges a /eel wire or cable mu/ be us$ = ! trail+ edge4 ,illu/ration3 ,fig4 #g4 ,/&>d ,h-#c ,w+ ,con/ruction4 ,sp>1 ,rib & ,drag ,/rut ,connections at ,left4 ,body ,connection ,fitt+ or ,h+e at ,"r4 ,note ,drag ,wire ,fitt+s4 ,c\rtesy ,a]ial ,age4 ,details ( ! fram+ ( ! ,/&>d ,h-#c are %[n by ,fig4 #g4 ,! figure at ! left gives a cle> idea ( ! connections betwe5 ! drag /ruts & sp>1 :ile ! view at ! "r %[s ! body connection at ! end ( ! sp>4 ,i am indebt$ to ,a]ial ,age = ^! sket*es4 ,! ma9 sp> is 9 a solid piece1 *annel$ out to ,i beam =m1 except at ! po9t :]e ! spruce drag /rut is atta*$4 ,at ! end ( ?is /rut is atta*$ a %eet /eel fitt+ t af=ds a means ( connect+ ! drag wires1 & = fa/5+ ! /rut to ! ma9 w+ sp>4 ,at ! po9t ( atta*m5t1 wood5 plates are fa/5$ to ei!r side ( ! sp>4 ,^! prev5t ! fitt+ bolts & ! fitt+ f slid+ along ! sp> :5 subject$ to an unev5 pull 9 ! wires4 ,a v5e] top & bottom plate /ill fur!r /r5g!n ?is jo9t & hold ! sub-rib 9 place4 ,! ma9 ribs are /r5g!n$1 at ! po9t :]e ! sp> passes ?r\gh ! rib web1 by small v]tical blocks4 ,9 ! "r h& figure ! /eel clevis is %[n bolt$ to ! sp>4 ,a lug = ! w+ drag wire is br\ght out f ! fitt+4 ,! clevis on ! w+ engages ) a simil> clevis on ! body ( ! ma*9e1 & ! two are fa/5$ toge!r ) a bolt or p94 ,illu/ration3 ,fig4 #h4 ,typical ,biplane ,w+4 ,gap = ,ail]on ,%[n at ,"r ,end ( ,w+4 ,left ,end ,re/s ,aga9/ ,fuselage1 ! ,obs]vation ,port ,be+ ,cut ,out at ! ,upp] ,left ,h& ,corn]4 ,drag ,wire ,brac+ ,cle>ly ,%[n4 ,c\rtesy ,a]ial ,age4 ,fig4 #h is a photograph ( a biplane w+ ) ! fram+ memb]s complet$ & ready = ! application ( ! fabric4 ,at ! "r is ! op5+ left = ! ail]on1 & at ! left is ! obs]vation port1 ! latt] com+ next to ! body4 ,z ?is is a l[] w+1 ! sockets = ! atta*m5t ( ! int]plane /ruts c be se5 on ! upp] & ne> edges ( ! ma9 sp>4 ,betwe5 ! sp>s are v ?9 wood /rips runn+ ) ! l5g? ( ! w+4 ,^! are ! ,batt5s us$ = /iff5+ ! ribs betwe5 ! po9ts ( support at ! sp>s4 ,z ! di/ance betwe5 ! sp>s is comp>atively great1 9 respect to ! ?ickness ( ! rib flanges1 "s sidewise support ( ?is k9d is necess>y4 ,! drag-brac+ cables cross ?ree rib spaces1 or are fa/5$ to e f\r? rib4 ,betwe5 ! front sp> 7at ! bottom71 & ! ent]+ edge1 are ! small /rips t s]ve z sub-ribs4 ,d\ble cross brac+ is us$ at ! inn] end ( ! w+ 7left71 :ile additional knee braces are plac$ at ! ail]on op5+1 & at ! out] tips4 ,?is is necess>y to )/& ! /resses due to assembl+ & h&l+1 r ?an = ! flight /resses4 ,fig4 #i is a ,/&>d ,w+ ready = cov]+4 ,be=e ! fabric is appli$1 a n>r[ clo? /rip is wrapp$ ov] ! trail+ edge1 z %[n1 & is /it*$ to ! frame4 ,?is =ms a means ( /it*+ ! ma9 cov]+ at ! re> edge1 :]e ! ends ( ! upp] & l[] surfaces meet4 99,w+ ,fabric or ,cov]+994 ,at ! pres5t "t unblea*$ ,iri% l95 is us$ almo/ exclusively = cov]+ ! w+ /ructure1 al?\gh 9 ! e>ly days ( fly+ rubb]iz$ fabrics 7 us$ to a great ext5t4 ,illu/ration3 ,fig4 #i4 ,/&>d ,h-#c ,w+ ,ready = ,cov]+4 ,op5+ = ,ail]on ,flap ,%[n at ,upp] ,left ,h& ,edge 7,trail+ ,edge74 ,aft] ! l95 is /ret*$ on ! w+ frame1 x is giv5 sev]al coats ( a special prep>ation commonly kn[n z ,dope to pro( ! fabric aga9/ moi/ure4 ,9 addition to wat]pro(+1 ! dope adds consid]ably to ! /r5g? ( ! fabric & %r9ks x tightly on ! ribs--mu* m ev5ly ?an c\ld be done by h&4 ,:5 completely ,dop$1 ! l95 %\ld be pro( aga9/ ! effects ( salt wat]1 moi/ure1 or extreme dryness1 & ! fabric mu/ be ,drum tight at e po9t on ! surface ( ! w+4 ,! l95 %\ld h a t5sile /r5g? ( at lea/ #ge p\nds p] in* ( wid? 9 any direction1 & weigh f #c4ge to #d4d ounces p] squ>e y>d4 ,x mu/ be wet spun1 free f fill+ matt] & uncal5d]$4 ,z a usual ?+1 ! wid? %\ld n be less ?an #cf in*es1 al?\gh ! wid? c be alt]$ to meet conditions ( rib spac+1 etc4 ,! ,u4,s4,a4 seaplane specifications 7#aiaf7 require a m9imum /r5g? along ! w>p ( #ge p\nds p] in* wid?1 & #he p\nds p] in* ( wid? along ! weft4 ,! foll[+ table gives ! prop]ties ( well kn[n w+ fabrics3 99,w+ ,dope994 ,w+ dopes are 9 ne>ly e case bas$ on cellulose--ei!r cellulose acetate or nitrate be+ ! mo/ common base4 ,?is has prov5 f> sup]ior to ! res91 copal1 gum or oil bases conta9$ 9 ord9>y v>ni%1 s9ce ! cellulose ( ! dope seems to amalgamate ) ! cellulose ( ! flax fib] & bond ! :ole into an integral /ructure4 ,! fact t ! dope mu/ be ela/ic b>s ! use ( %ellac or o!r h>d res9 solutions4 ,! solv5ts us$ = ! cellulose dopes v>y ) ! mak]s1 "s us+ amyl-acetate1 tetra*lore?ane1 etc41 :ile o!rs use special secret comp\nds t are be/ adapt$ = _! bases4 ,_m ( ! solv5ts give (f poison\s gases 9 dry+1 & ?is mu/ be gu>d$ aga9/ by good v5tilation4 ,! vapor ( tetra*lore?ane is p>ticul>ly dang]\s1 & has result$ 9 _m dea?s4 ,illu/ration3 ,fig4 #aj4 ,complete ,fram+ ,plan ( ,typical ,monoplane ,/ructure4 7,a7 ,pilot4 7,b7 ,pass5g]4 7,m7 ,motor4 7,s7 ,/abiliz]4 7,e7 ,elevator4 7,r7 ,v]tical ,rudd]4 ,dop$ surfaces h f #aj to #be p] c5t great] t5sile /r5g? & resi/ance to te>+ ?an ! undop$ l951 & increases ! weight ( ! fabric by ab\t #j4g ounce p] squ>e y>d = ea* coat appli$4 ,"u ord9>y wea!r conditions1 dope w require f #bj to #dj m9utes p] coat = dry+1 & at lea/ "o-half h\r %\ld be all[$ betwe5 ea* coat4 ,wea!r conditions h a great effect on ! action ( dope1 & ) cellulose comp\nds ! be/ results are obta9$ 9 a clean dry room1 well w>m$1 & )\t drafts4 ,on ra9y days ! l95 is damp & ! dope does n set well1 & ?is tr\ble is n greatly help$ by artificial heat4 ,drafts cause :ite spots & /reaks1 especially if cold air is all[$ to ent] directly ^u ! w>m w+ surface4 ,to prev5t drafts ! v5tilat+ ducts %\ld be ne> ! floor1 & z ! vapor is heavi] ?an ! air1 & fl[s d[nw>ds1 ?is means ( v5tilation is entirely practicable4 99,apply+ ! ,dope994 ,! numb] ( coats dep5d ^u ! "* ( ! job1 b at lea/ five coats %\ld be appli$1 & pref]ably sev54 ,on ! be/ grade ( "w1 ! dope is g5]ally cov]$ ) ?ree or m f9al coats ( sp> v>ni%1 al?\gh ?is is n absolutely necess>y4 ,= ord9>y "w1 dope alone on ,iri% l95 has prov$ v satisfactory = l& ma*9es1 five coats be+ ! usual am\nt appli$ on exhibition a]oplanes & planes = amateur use4 ,sev5 coats ( dope ) ?ree coats ( sp> v>ni% are specifi$ = milit>y ma*9es t are to be us$ on salt wat]4 ,seaplanes are subject$ to conditions t are p>ticul>ly h>d on fabric & mu/ be protect$ accord+ly4 ,9 apply+ ! dope1 at lea/ "o-half h\r %\ld be all[$ = dry+ betwe5 ea* coat1 & m if possible4 ,! fir/ two coats %\ld be pa9t$ on lightly1 ! purpose be+ simply to fill ! pores ( ! fabric & to prev5t ! succe$+ coats f s9k+ ?r\gh4 ,if ! fir/ two coats are too heavy1 ! dope filt]s ?r\gh ! me% ( ! l95 & drops on ! l[] surface1 caus+ spots & a wa/e ( a v exp5sive mat]ial4 ,dope is exp5sive ev5 ) ! greate/ c>e ex]cis$ 9 its application1 & ! writ] has se5 cases :]e ! fir/ two coats 7 s heavily appli$ t fully #ej p] c5t ( ! fluid ran ?r\gh & cak$ 9 among ! /ructural p>ts ( ! ma*9e4 ,?is ran ! dop+ exp5se up to a t]rific figure4 ,! clo? %\ld be dry1 & ! "w p]=m$1 if possible1 on a dry day4 ,to save dope1 nev] take out ( ! supply drum m ?an c be us$ = "o coat1 = ! dope soon becomes tacky on exposure to ! air1 & a satisfactory job is h>d to obta9 if x gets 9 ?is condition4 ,illu/ration3 ,fig4 #aj;a4 ,te/+ ! ,w+ ,/ructure ( a ,curtiss ,biplane by ,means ( ,s& ,bag ,load+4 ,! ,w+s ,are ,turn$ ,upside ,d[n & a ,s& ,load ,is ,laid ,uni=mly ,ov] ! ,w+s4 ,s ,t ,!y ,produce a ,load ,equal to1 or ,great] ,?an1 ! ,flight ,load4 ,9 plac+ ! fabric on ! w+s1 p>ticul> c>e mu/ be tak5 9 /ret*+ s z n to h x too tight :5 cellulose dope is us$4 ,! dope %r9ks ! l95 to a v consid]able ext5t1 & if x is too tight to beg9 )1 ! /ress due to %r9kage w place an excessive /ress on bo? ! fabric & ! /ructure4 ,:5 ( ! prop] tautness1 ! fabric %\ld s\nd l a drum :5 snapp$ ) ! f+]4 ,any less t5sion ?an ?is w p]mit ! fabric to sag badly :5 "u ! air pressure & r$uce ! effici5cy ( ! w+s4 ,9 fa/5+ ! clo? x %\ld be j /ret*$ taut & no m4 ,9 damp wea!r ! clo? c be /ret*$ a little tight] ?an 9 dry wea!r4 99,transp>5t ,cov]+s994 ,9 "s types ( battle-planes & sc\ts1 a "p ( ! w+ section directly above ! pilot is cov]$ ) a transp>5t firepro( cellulose %eet1 mu* resembl+ celluloid4 ,?is p]mits ! pilot to see above him ?r\gh ! ov]hang+ w+1 & is ( great value 9 action4 ,9 "s cases1 a /rip is plac$ on ! l[] w+s along ! sides ( ! body s t ! gr\nd is also easily visible4 ,^! cellulose %eets w n crack nor spl9t]1 & are ne>ly z flexible z rubb]4 ,celluloid ( ! ord9>y v>iety mu/ n be us$1 = ?is is easily ignit$ & is likely to />t a disa/r\s fire4 99,plac+ ! ,fabric on ! ,w+s994 ,9 "s a]oplanes ! seams ( ! fabric are run p>allel to ! ribs1 & are tack$ or sew$ directly to !m1 :ile 9 o!r cases ! seams are run diagonally across ! plane or on ! bias4 ,diagonal seams are mo/ satisfactory1 & if c>e is tak5 !re is no m wa/e ( l95 ?an ) ! /raight seam4 ,! seams %\ld be ( ! d\ble-lapp$ or ,engli% welt type1 & ?is ( c\rse necessitates sew+ be=e ! fabric is plac$ on ! w+s4 ,! seams us$ on ov]coats are satisfactory = ?is purpose1 & give a cov]+ t w n /ret* nor bag4 ,"s use l95 ?read & o!rs use silk1 b ! l95 is pref]able1 s9ce dope (t5 causes silk to rot4 ,! seams %\ld be cov]$ ) l95 to protect !m f ! wea!r & to prev5t ! entrance ( wat] to ! int]ior woodwork4 ,ord9>ily1 ! w+ is turn$ upside d[n = cov]+1 ) ! concave side upp]mo/4 ,! seams are sew$ toge!r s t ! complet$ fabric is wid] ?an ! l5g? ( ! w+ & is a little long] ?an is necess>y to wrap entirely ar\nd ! wid? ( ! w+4 ,! fabric is !n tempor>ily fa/5$ along ! trail+ edge1 is pass$ "u ! w+ to ! front edge1 & ov] ! concave upp] side back to ! trail+ edge4 ,at ?is po9t ! excess mat]ial w hang d[n ov] ! re> edge4 ,) ! w+ 9 its upside d[n position1 ! convex side w be at ! bottom1 & if a weight is hung on ! ov]hang+ mat]ial at ! re> edge1 ! clo? w be pull$ tight aga9/ ! l[] convex side & /raight across & above ! concave side4 ,! fabric at ! top is !n /ret*$ along ! cordal l9e ( ! ribs4 ,by lay+ a n>r[ bo>d on top ( ! fabric1 & ne> ! ent]+ edge1 ! fabric c be br\ght d[n uni=mly along ! concave edge ( ! ribs1 & by tack+ or sew+ z ! bo>d is mov$ back ! concave face c be cov]$ )\t fur!r tr\ble4 ,aft] ! concave face is dispos$ (1 ! w+ c be turn$ ov] & ! fabric is !n fa/5$ to ! convex side ( ! ribs4 ,illu/ration3 ,fig4 #aa4 ,me?od ( ,/ret*+ ,fabric on ,w+s4 ,fabric ,passes ,"u & ,!n ,ov] ,concave ,side & ,is ,press$ ,d[n into ,holl[ by a ,bo>d z ,%[n4 ,"o me?od ( fa/5+ ! l95 is to lay tape ov] ! ribs1 & !n drive tacks ?r\gh ! tape & fabric into ! rib4 ,! tape keeps ! tacks f te>+ ?r\gh ! l954 ,! tape %\ld be heavy l95 ( f #c_/d to #a #a_/d in*es wide1 & laid 9 cellulose be=e tack+1 s t ! tape w be cem5t$ to ! fabric & ! solution w be driv5 into ! tack holes4 ,aft] ! tape is 9 place1 x %\ld be cov]$ ) n less ?an ?ree coats ( cellulose dope be=e ! ma9 surface is treat$4 ,?is gives an additional ?ree coats ov] ! tape :]e x is mo/ ne$$ = protection aga9/ moi/ure4 ,9 any case1 ! seam or tack+ /rip %\ld be press$ d[n s t x projects z little z possible above ! g5]al surface ( ! w+4 ,tack+ is n desirable1 = tacks & nails always t5d to split ! ?9 memb]s ( ! rib1 & v (t5 corrode ! clo? & weak5 ! fabric4 ,?is has result$ 9 ! :ole fabric be+ ripp$ (f :ile 9 flight4 ,iron or /eel tacks %\ld nev] be us$1 z !y de/roy ! /r5g? ( ! fabric v rapidly by ! =mation ( ru/1 & p>ticul>ly ) sea-planes us$ on salt wat]4 ,sew+ ! fabric to ! ribs ) l95 ?read is ! mo/ satisfactory me?od & is 9 g5]al use among high-grade build]s4 ,! fabric c be /it*$ to b&s ( ?read or tape1 ! latt] be+ wrapp$ ab\t ! rib4 ,/it*es c also be tak5 f "o surface /raight ?r\gh to ! o!r4 ,! ?read or tape b&s on ! ribs are m]ely wrapp+s tak5 ar\nd ! rib flange1 & ?r\gh ! light5+ holes1 ^! b&s usually be+ ab\t #d in*es ap>t4 ,!y at once tie ! flange to ! web & =m a s(t surface into :i* to take ! /it*es4 ,fig4 #d 9 ,*apt] ,x %[s ! ?read b&s 7d7 wrapp$ ar\nd ! rib flange 7,g71 & ?r\gh ! light5+ hole1 ! fabric ly+ above & bel[ ! rib flanges z %[n4 ,a section view ?r\gh ! rib & fabric is %[n at ! "r4 99,v>ni%+994 ,:5 v>ni% is to be us$ ov] ! dope1 only ! be/ grade ( sp> v>ni% %\ld be us$1 s9ce any o!r k9d is soon de/roy$ by moi/ure4 ,f two to ?ree v>ni% coats w be suffici5t1 & ea* coat %\ld be ?or\ghly dri$ & s&pap]$ be=e ! next is appli$1 c>e be+ tak5 n to injure ! fabric ) ! s&pap]4 ,s&pap]+ betwe5 ! dope lay]s is n necess>y1 s9ce ea* successive coat p>tially dissolves ! prec$+ coat1 & ?us welds ! lay]s toge!r4 ,v>ni%1 h[ev]1 does n act 9 ?is way1 & ! coats mu/ be r\gh5$4 ,%ellac rots ! l95 & %\ld n be us$4 ,! ,gov]nm5t specifies "o coat ( flexible :ite enamel 9 :i* a small quantity ( lead *romate is mix$4 ,?is is appli$ ov] ! la/ coat ( v>ni%4 ,! lead *romate filt]s out ! act9ic rays ( ! sun1 ?us r$uc+ ! injuri\s effect ( ! sunlight on ! cov]+4 ,if color+ matt] is add$ to ! dope1 x %\ld be 9 liquid =m1 z p[d]s de/roy ! /r5g? & texture ( ! dope deposit4 ,illu/ration3 ,fig4 #ab4 ,w+ ,/ructure ( ,h&ley-,page ,giant ,biplane4 ,c\rtesy ,a]ial ,age4 99,pat*+ ,fabric994 ,! majority ( dopes c be us$ z cem5t = pat*+1 b z dope w n /ick to v>ni%1 all ( ! v>ni% ar\nd ! pat* mu/ be ?or\ghly remov$ ) "s good v>ni% remov]4 ,! v>ni% mu/ be ?or\ghly clean$ (f or !re w be no results4 ,be=e apply+ ! dope1 ! pat* mu/ be well /it*$ all ar\nd ! edges1 !n cem5t$ ) ! dope4 ,! pat* mu/ n[ be cov]$ ) at lea/ five coats ( ?9 dope z 9 f9i%+ ! surface4 ,p>ticul> att5tion mu/ be paid to fill+ ! dope 9 ! /it*+4 ,,*apt] ,x4 ,,w+ ,,con/ruction ,,details4 99,types ( ,ribs994 ,! rib fir/ us$ by ! ,wright ,bro!rs consi/$ ( two spruce /rips sep>at$ by a s]ies ( small p9e blocks4 ,practically ! same con/ruction 0 us$ by ,etri* 9 ,au/ria4 ,) ! com+ ( ! monoplane1 & its deep heavy sp>s1 ! old ,wright rib 0 no long] suitable = ! blocks 7 n effici5t 9 ?ick w+ sections4 ,! *anges 9 ! w+ =m !n l$ to ! almo/ univ]sal adoption ( ! ,i type rib 9 :i* an upp] & l[] flange /rip are sep>at$ by a ?9 v]tical web ( wood4 ,at pres5t ! ,i rib is us$ on ne>ly e well kn[n ma*9e4 ,x is v /rong & light1 & is capable ( tak+ up ! end ?ru/ ( ! drag wires1 z well z tak+ c>e ( ! b5d+ /resses due to ! v]tical load+ or lift4 ,fig4 #a %[s ! orig9al ,wright rib ) ! ,batt5s or flanges 7g7 & ! spac+ blocks ,b4 ,! front sp> is at ! lead+ edge 7,f71 & ! re> sp> at ,s4 ,an ,i beam1 or ,monoplane type is %[n by ,fig4 #b1 & z w be se5 is m suitable = deep sp>s su* z 7,f'7 & ,s'4 ,! upp] & l[] flanges 7g7 are sep>at$ by ! ?9 p]=at$ web 7w71 ! sectional view at ! "r %[+ ! connection betwe5 ! flanges & ! web4 ,light5+ holes 7h7 r$uce ! weight ( ! web1 ) en\gh mat]ial left along ! c5t] ( ! web to resi/ ! horizontal =ces4 ,! web is glu$ into a slot cut 9 ! flanges1 & ! flanges are !n ei!r tack$ to ! web ) f9e nails1 or b\nd to x by turns ( ?read ar\nd ! flange4 ,on ! av]age ma*9e1 ! web is ab\t #c_/af ?ick1 :ile ! flanges are f #c_/d to #a in* wide1 & f #c_/af to #a_/d in* ?ick4 ,on ! v l>ge ma*9es1 ! dim5sions ( c\rse are mat]ially increas$4 ,at ! /rut locations 9 biplanes1 & ! po9t ( cable brac+ atta*m5t 9 monoplanes1 ! ribs are increas$ 9 /r5g? unless ! end ?ru/ ( ! /ay wires is tak5 up by a sep>ate /rut4 ,at ! po9t ( /ay connection 9 ! old ,nieuport monoplane ! rib 0 provid$ ) a d\ble web ?us mak+ a holl[ box =m ( section great en\gh to acc\nt = ! diagonal pull ( ! /ays4 ,illu/ration3 ,fig4 #a4 ,wright ,type ,rib ) ,batt5s & ,block ,sep>ators4 ,fig4 #b4 ,monoplane or ,i ,type ( ,rib ) ,solid ,web4 ,fig4 #c %[s ! ,nieuport monoplane ribs1 :i* are good examples ( box ribs4 ,! sections at ! left are tak5 ?r\gh ! c5t] ( ! ribs4 ,! w+ *ord tap]s f ! body to ! w+ tip1 :ile ! ?ickness ( ! w+ section is greate/ at ! middle1 & tap]s d[n bo? t[>d ! tips & t[>d ! body4 ,! upp] section is locat$ at ! body1 ! second is locat$ midway betwe5 ! body & ! tip1 & ! o!r two are ne> ! tips1 ! bottom be+ ! la/ rib at ! out] end4 ,! ribs %[n are ( box =m z !y are at po9ts ( connection1 b ! int]m$iate ribs are ( ! ,i type %[n by ,fig4 #b4 ,illu/ration3 ,fig4 #c4 ,nieuport ,monoplane ,ribs4 ,?is ,w+ ,is ,?icke/ 9 ! ,c5t] & ,wa%es ,qut ,t[>d ,ei!r ,end1 ,?us ,mak+ ,all ( ! ,ribs ,diff]5t 9 ,curvature & ,?ickness4 ,at ! ,po9t ( ,/ay ,wire ,atta*m5t ,d\ble ,webb$ ,box ,ribs ,are ,us$4 99,rib ,mat]ial994 ,9 ,am]ican a]oplanes1 ! flanges ( ! ribs are g5]ally made ( spruce4 ,! webs are ( popl>1 :itewood1 cottonwood or simil> light mat]ial4 ,!re is n a great deal ( /ress on a rib1 & ! /ronge/ mat]ial is n necess>y1 b z !re are a great _m ribs 9 a w+ assembly lightness is a prim>y consid]ation4 ,a few ounces diff]5ce on ea* rib makes a great deal ( diff]5ce 9 ! total weight1 especially :5 !re are #hj or m ribs 9 a complete ma*9e4 ,exception to ! above mat]ials w be f\nd 9 ! ,curtiss ,sup]-,am]ican ,fly+ ,cruis] :i* has ribs ) p9e webs & bir* flanges4 ,european a]oplane practice makes use ( h>dwood 9 ! ribs4 99,web ,/iff5]s994 ,! webs be+ ?9 & deep1 & cut = light5+ z well1 ne$ brac+ at ! po9ts :]e conc5trat$ loads are plac$1 su* z at ! front & re> sp>s1 & at po9ts betwe5 ! light5+ holes4 ,by glu+ ?9 /rips to ! webs 79 a v]tical direction71 & s t ! tops & bottoms ( ! /rips come tight aga9/ ! upp] & l[] flanges1 a great deal ( ! /ra9 on ! web c be avoid$4 ,! /iff5+ blocks are %[n by 7x7 9 ,fig4 #d1 & are plac$ on bo? sides ( ! front & re> sp>s ,f & ,s1 & also betwe5 ! light5+ holes ,h4 ,illu/ration3 ,fig4 #d4 ,details ( ,i ,type ,rib1 ,%[+ ,light5+ ,holes & ,/iff5]s4 99,flange ,fa/5+s994 ,9 ! section at ! "r ( ,fig4 #d x w be se5 t ! web is ins]t$ into a groove cut 9 ! flanges & is !n glu$ into place4 ,x w\ld be unsafe to tru/ entirely to ! glue1 ow+ to ! effects ( ag+1 moi/ure & heat1 & consequ5tly "s additional means ( fa/5+ mu/ be _h4 ,x has be5 cu/om>y to nail ?r\gh ! flange into ! web1 b z ! web is only ab\t #c_/af in* ?ick x is likely to split4 ,an approv$ me?od is %[n 9 ,fig4 #d 9 :i* ,iri% l95 ?read wraps 7d7 are pass$ ?r\gh ! light5+ holes 7,h71 & ov] ! flanges 7,g74 ,! ?read is coat$ ) glue be=e wrapp+ & aft]1 & :5 dry x is ?or\ghly v>ni%$ = protection aga9/ moi/ure4 ,! b&s are spac$ f #c to #d in*es ap>t4 ,if nails are us$ !y %\ld be brass nails--nev] /eel or iron4 ,at ! po9ts 7,f7 & 7,s7 :]e ! sp>s pass ?r\gh ! web1 ! web is entirely cut out s t ! flanges ord9>ily lie directly on ! sp>s4 ,9 ?is case x is necess>y to bevel ! sp> s t x at lea/ approximately fits ! curve ( ! flange4 ,sometimes :5 a full size sp> is impossible1 z 9 cases :]e ! sp> tap]s t[>d ! tips1 wood pack+ pieces may be plac$ betwe5 ! flange & ! sp>2 tap]$ to make up = ! curve4 ,! flanges 9 any case mu/ be securely fa/5$ to ! sp> by brass wood screws z at 7e71 & ! edges ( ! web %\ld fit tightly aga9/ ! sides ( ! sp>s4 99,w+ ,batt5s994 ,! w+ batt5s run along ! l5g? ( ! w+s1 f end to end1 & betwe5 ! sp>s1 & s]ve to brace ! ribs sideways z %[n 9 "s ( ! g5]al views ( ! w+ assembly4 ,to accommodate ! batt5s1 ! op5+s 7f7 are cut directly "u ! flange4 ,usually ! batt5s are ?9 spruce /rips f #c_/af to #a_/d in* ?ick & #a_/b in* wide1 & %\ld be run ?r\gh ! web at a po9t ne> ! /iff5]s4 ,! ?ickness f ! top ( ! flange to ! "u side ( ! light5+ hole is f #a_/b to #c_/d in* z indicat$ by 7,c74 99,/r5g? ( ,wood ,ribs994 ,! /r5g? ( a rib = any individual case c be f\nd by ! me?od us$ 9 comput+ beams1 ! rib usually be+ assum$ to h a uni=mly di/ribut$ load1 al?\gh ?is is n actually ! case1 z be=e expla9$4 ,! great] "p ( ! load 9 normal flight is ne> ! front sp>1 b ?is %ifts back & =? ) ! angle ( incid5ce s t !re is no real /ation>y po9t ( application1 & ! rib mu/ be figur$ = ! maximum condition4 ,! total load c>ri$ by "o ( ! int]m$iate ribs is due to ! area betwe5 ! ribs1 or to ! unit load+ multipli$ by ! rib spac+ & *ord4 ,! portion ( ! rib betwe5 ! sp>s c be calculat$ z a uni=mly load$ beam1 support$ at bo? ends4 ,! ent]+ edge 9 front ( ! sp>1 & ! trail+ edge to ! re> may be tak5 z uni=mly load$ beams support$ at "o end4 ,! proportion ( ! loads com+ on ! ends & c5t] position c be tak5 f ! pressure di/ribution diagrams z %[n "u ,a](oils4 ,a numb] ( te/s 7 made on ribs by ,mr4 ,he9ri* ( ! ,he9ri* ,a]oplane ,company1 ! ribs be+ built up on %ort pieces ( sp> s t actual conditions 7 approa*$4 ,in/ead ( us+ a di/ribut$ load1 su* z usually comes on ! rib1 a conc5trat$ load 0 plac$ at ! c5t]4 ,if ! rib 7 uni=m 9 section ! equival5t uni=mly di/ribut$ load c\ld be tak5 z "o-half ! conc5trat$ load1 b because ( ! light5+ holes ?is w\ld n be v exact4 ,x w\ld be on ! safe side1 h[ev]1 z su* a te/ w\ld be m sev]e ?an ) a uni=m load4 ,! ribs 7 ( ! same type z %[n 9 ,fig4 #e1 & 7 plac$ #cb4e in*es ap>t4 ,! front sp> 0 #b #g_/af in*es deep1 ! re> sp> #b #a_/af in*es deep1 & ! ov]all dep? ( ! rib at ! c5t] 0 #c #a_/h in*es4 ,! rib flanges 7 ( :ite wood #c_/d in* wide1 & #c_/af in* ?ick4 ,9 rib ,no4 #a ! web 0 solid :itewood1 #c_/af in* ?ick1 & 9 ribs ,nos4 #b & #c1 ! webs 7 mahogany ?ree-ply v5e] 7#e_/cb in* ?ick74 99,te/ ( ,rib ,no4 #a994 ,!re are #e light5+ holes betwe5 sp>s1 ) #b in*es ( mat]ial left betwe5 ! holes1 & #a_/b in* betwe5 fir/ hole & front sp> op5+4 ,) #ie p\nds conc5trat$ load at ! c5t]1 ! fir/ rupture appe>$ z a split betwe5 ! fir/ hole & sp> op5+4 ,at #aai p\nds1 ! flanges _h pull$ away f "o side ( ! sp>1 & #a_/h in* away f ! web4 ,full failure at #abg4e p\nds4 ,web 0 split betwe5 ea* light5+ hole ) a complete cross break at c5t] ( web1 ! latt] be+ caus$ by a brad hole 9 ! web4 99,te/ ( ,rib ,no4 #b994 ,lam9at$ web1 ) no brads driv5 opposite light5+ holes4 ,at #adj p\nds rib deflect$ #e_/af in*1 & :5 reliev$ sprang back only #c_/af in*4 ,) #age p\nds1 ! deflection aga9 0 #e_/af in*1 b ! rib cont9u$ to b5d sl[ly1 ! flanges pull+ away f ! web & sp>s4 ,! wood 0 n brok5 any:]e1 ! failure be+ 9 ! brads & glue4 99,te/ ( ,rib ,no4 #c994 ,same mat]ials z ,no4 #b1 b web 0 fitt$ inside ( ! ,i beam sp> & ! rib flanges 7 screw$ to ! sp>4 ,at #age p\nds !re 0 no sign ( rupture any:]e1 & ! deflection 0 #e_/af in*4 ,at #ahe p\nds ! rib broke v sudd5ly & cleanly1 & 9 su* a way z to indicate t ?is 0 ! true /r5g? ( ! rib4 ,! normal load+ on ! rib 9 flight 0 #ag4e p\nds1 uni=mly di/ribut$1 s t ) a conc5trat$ load ( #cgj p\nds equival5t1 ! safety factor 0 #ba4a4 ,! conclusions to be arriv$ at f ?is te/ are z foll[s3 7#a7 ,:5 a solid s(t wood web is us$1 !re %\ld be at lea/ #b #a_/b to #c in*es betwe5 light5+ holes4 7#b7 ,a lam9at$ or ?ree-ply web is ! be/4 7#c7 ,no brads %\ld be driv5 opposite light5+ holes4 7#d7 ,! web %\ld fit closely to ! sp> sides & ! flange ( ! rib %\ld be tightly screw$ to ! top & bottom ( sp>4 ,! above gives an idea z to ! /r5g? ( ! usual =m ( wood rib1 & c be us$ comp>atively = o!r cases if ! read] is n famili> ) /r5g? calculations4 ,illu/ration3 ,fig4 #g4 ,rib ,b5d+ ,press = ,curv+ ! ,rib ,flanges4 99,mak+ ! ,rib994 ,wood5 webs are cut out on ! b& saw1 & ! webs are s simple t !re is n mu* m to be said on ! subject4 ,! flanges1 h[ev]1 mu/ be /eam$ & b5t to ! ne>ly correct =m be=e assembly4 ,aft] plan+ to size & cutt+ ! groove = ! reception ( ! web1 ! ribs are plac$ 9 ! /eam] & ?or\ghly /eam$ = at lea/ an h\r4 ,a rib flange press %[n by ,fig4 #g consi/s ( two heavy blocks ) ! inn] faces cut approximately to ! rib outl9e4 ,! /eam$ ribs are !n plac$ betwe5 ! blocks1 ! bolts are screw$ d[n tight1 & is left = #bd h\rs s t ! /rips h ample "t to cool & dry4 ,= ! amateur or small build]1 ! /eam] c be made ( a galvaniz$ d[n-sp\t connect$ ) an op5+ cut 9 ! top ( an ord9>y wa% boil]4 ,"o end ( ! sp\t is p]man5tly seal$1 :ile ! o!r is provid$ ) a removable cov] s t ! /rips c be ins]t$4 ,a hole cut ne> ! c5t] ( ! sp\t is connect$ to ! op5+ 9 ! boil] cov] by a %ort l5g? ( sp\t+ or pipe4 ,! sp\t %\ld be made l>ge en\gh 9 diamet] to conta9 all ( ! ribs t c be press$ at "o "t1 & %\ld be long en\gh to accommodate long] pieces su* z ! fuselage long]ons1 etc4 ,:5 remov$ f ! press1 ! rib flanges c be glu$ to ! webs tak+ c>e t ! glue is hot1 & t x ?or\ghly cov]s ! groove surface4 ,! rib mu/ n[ be held accurately 9 place 9 a second =m1 s t ! true rib outl9e w be reta9$ until ! glue drys4 ,a great deal dep5ds ^u ! accuracy ( ! second =m1 & ! accuracy ) :i* ! web outl9e is cut4 ,! l>g] manufactur]s use metal rib =ms or jigs1 b ! small build] mu/ be cont5t ) a wood5 =m consi/+ ( a bo>d fitt$ ) suitable reta9+ cleats1 or lugs4 ,! outl9e ( ! a](oil is drawn on ! bo>d1 ! tips ( ! cleats are br\ght to ! l9e1 & are screw$ to ! bo>d s t !y c be turn$ back & =? = ! admission & release ( ! ribs4 ,! /rip b5d+ press 9 ,fig4 #g is only int5d$ to b5d ! flanges approximately to =m1 & h5ce two lay]s may be put 9 ! press at "o "t )\t mu* error4 99,w+ ,sp>s994 ,9 ,am]ican a]oplanes ^! memb]s are usually ( ! solid ,i =m = m$ium size exhibition & tra9+ ma*9es1 b = small fa/ a]oplanes1 :]e e ounce mu/ be sav$1 !y are g5]ally ( ! built up type1 t is1 made up ( two or m memb]s4 ,9 ,europe1 built up con/ruction is m common ?an 9 ?is c\ntry1 & is f> pref]able = any ma*9e t ju/ifies ! additional "t & exp5se4 ,! w+ sp>s are ! heavie/ & mo/ important memb]s 9 ! w+ & no tr\ble %\ld be sp>$ to h !m z light z ! /r5g? & exp5se w p]mit4 ,!y are subject$ to a r sev]e & complex s]ies ( /resses2 b5d+ due to ! load c>ri$ betwe5 supports1 compression due to ! pull ( ! /ay wires1 b5d+ due to ! twi/ ( non-c5tral wire fitt+s1 /resses due to drag & ^? caus$ by sudd5 deviations 9 ! flight pa? & by ! torque ( ! motors4 ,^! %\ld be accurately work$ out by means ( /ress diagrams if ! be/ weight effici5cy is to be obta9$4 ,illu/ration3 ,fig4 #i4 ,types ( ,w+ ,sp>s4 7,a7 ,is ! ,i ,beam ,type4 7,b7 ,box ,sp>4 7,c7 ,is ,composite ,wood & ,/eel1 ,wrapp$ ) ,tape4 ,a numb] ( diff]5t w+ sp> sections are %[n by ,figs4 #i1 #aj1 #aa4 ,sp> 7,a7 9 ,fig4 #i is ! solid "o piece ,i type 7g5]ally spruce71 *annel$ out along ! sides to remove ! ineffici5t mat]ial at ! c5t]4 ,! load 9 ?is case is assum$ to be 9 a v]tical direction4 ,9 resi/+ b5d+ /resses1 x %\ld be not$ t ! c5tral portion ( ! mat]ial is n ne>ly z effective z t at ! top & bottom1 & t ! same weight ( mat]ial locat$ top & bottom w produce _m times ! results obta9$ ) mat]ial locat$ along ! c5t] l9e4 ,at po9ts ( connection1 or :]e bolts pass ?r\gh ! sp>1 ! *annel+ is discont9u$ to comp5sate = ! mat]ial cut away by ! bolt & fitt+s4 ,sp> 7,b7 is ( ! holl[ type1 made 9 two halves & glu$ toge!r ) h>dwood d[el /rips4 ,! d[el+ /rips may be at ! top & bottom z %[n1 or on ! horizontal c5t] l9e z %[n by ,sp> 7,j74 ,! mat]ial ( ! box portion is g5]ally ( spruce4 ,?is is a v effici5t section z ! mat]ial lies ne> ! out] edge 9 e direction1 & (f]s a high resi/ance to b5d+1 bo? horizontally & v]tically4 ,un=tunately a great deal dep5ds ^u ! glu$ jo9ts1 & ^! require c>eful protection aga9/ moi/ure4 ,!re is absolutely no means ( nail+ or key+ aga9/ a slipp+ t5d5cy or horizontal %e>4 ,! be/ arrangem5t to insure aga9/ slipp+ ( ! two halves is to tape ar\nd ! outside z %[n by sp> 7,e74 ,?is is /rong l95 tape & is glu$ c>efully to ! sp>1 & ! :ole con/ruction is pro($ aga9/ moi/ure by sev]al coats ( sp> v>ni% & %ellac4 ,9 addition to ! /r5g!n+ effect ( ! tape1 x also prev5ts ! wood f spl9t]+ 9 accid5ts4 ,illu/ration3 ,fig4 #aj4 ,f\r ,types ( ,w+ ,sp>s1 ! ,sp> ,d ,be+ a ,simple ,/eel ,tube z ,us$ 9 ! ,caudron & ,breguet ,ma*9es4 ,sp> 7,c7 consi/s ( a c5tral a% ,i section1 ) /eel /rips 9 ! grooves4 ,two spruce side /rips are plac$ at ei!r side z /iff5]s aga9/ lat]al flexure1 & ! entire con/ruction is tap$ & glu$4 ,?is is v effective aga9/ d[nw>d /resses1 & = its /r5g? is v compact4 ,s9ce spruce is mu* /iff] ?an ei!r ! ?9 /eel /rip1 or ! a%1 x is plac$ on ! outside4 ,sp> 7,d7 9 ,fig4 #aj has be5 describ$ be=e4 ,fig4 7,f7 consi/s ( two spruce *annels plac$ back to back1 ) a v]tical /eel /rip betwe5 !m4 ,aga9 ! spruce is us$ z a side /iff5]1 & 9 ?is case probably also takes a consid]able portion ( ! compression load4 ,sp> 7,g7 is a special =m ( box sp> us$ :5 ! sp> is at ! ent]+ edge ( ! w+1 ! curv$ nose be+ curv$ to ! %ape ( ! a](oil nose4 ,9 ,fig4 #aa 7,h71 a c5t] a% ,i is /iff5$ by two spruce side plates1 ! a% memb] tak+ ! b5d+ mom5t1 & ! spruce ! compression4 ,sp> 7,i7 has a comp\nd c5tral ,i1 ! upp] & l[] flanges be+ ( a% & ! c5t] web ( ?ree ply v5e]4 ,! two out] plates are ( spruce4 ,?is %\ld be a v effici5t section1 b "o t w\ld be difficult & co/ly to build4 ,fig4 7,j7 is ! same z 7,b71 except t ! p>t+ lies 9 a horizontal plane4 ,sp> 7,k7 has a% top & bottom memb]s1 & spruce or v5e] side plate4 ,! resi/ance ( ?is %ape to side ?ru/ or twi/ w\ld be v slight4 ,! sides are bo? screw$ & glu$ to ! top & bottom memb]s4 ,illu/ration3 ,fig4 #aa4 ,built-,up ,wood5 ,w+ ,sp>s1 ,commonly ,us$ ) ,european ,a]oplanes4 ,! front end ( a ,hansa-,br&5burg w+ is %[n by ,fig4 #ab1 ! box sp> & its in/allation be+ drawn to scale & ) dim5sions 9 millimet]s4 ,! top & bottom are slop$ 9 agreem5t ) ! rib flange curve1 & ! rib web is /r5g!n$ by /iff5]s at ei!r side ( ! sp>4 ,! h>dwood d[el /rips are at top & bottom z 9 ,fig4 ,b1 & :5 plac$ 9 ?is position ! glu$ jo9t is n subject$ to ! horizontal %e> =ces4 ,! walls are ?ick] at top & bottom ?an at ! sides1 9 ord] to resi/ ! great] v]tical =ces4 ,= ! same reason is deep] ?an x is wide4 ,z w be rememb]$1 ! drag is v mu* less ?an ! lift1 & aga91 ! drag /ress is greatly r$uc$ by ! int]nal drag wire brac+4 99,lead+ ,edge ,con/ruction994 ,9 ! e>ly ,bl]iot monoplanes ! lead+ edge 0 ( %eet alum9um1 b5t into ,u =m ov] ! nose ( ! rib4 ,9 mod]n biplanes1 ?is edge is g5]ally ( ,u =m holl[ spruce1 ab\t #c_/af in* ?ick4 ,ano!r favorite mat]ial is flatt5$ /eel tub+1 ab\t #a_/b x #a_/d1 & ( v light gauge1 ! long side be+ horizontal4 ,! tube has ! advantage ( be+ mu* ?9n] & mu* /iff] ?an ! o!r =ms1 & ! ?9 edge makes x v suitable = c]ta9 types ( a](oils4 ,! w+ tip b[s are g5]ally ( holl[$ a% & are fa/5$ to ! sp> ends1 lead+ edges1 & trail+ edges ) maple d[els1 ! jo9t be+ ( a long sc>f$ =m4 ,:5 ! sc>f$ jo9t is d[el$ toge!r1 x is wrapp$ ) "o or two lay]s ( glu$ l95 tape4 ,9 "s types ( ma*9es ! top surface ( lead+ edge is cov]$ ) ?9 two ply wood f ! extreme front edge to ! front sp>4 ,?is ma9ta9s ! a](oil curve exactly at ! mo/ critical po9t ( lift+1 & also /iff5s ! w+ aga9/ ! drag =ces4 ,illu/ration3 ,fig4 #ab;b4 ,an ,old ,type ( ,curtiss ,biplane ,/rut ,socket1 at ,left4 ,at ! ,"r ,is a ,m ,mod]n ,type 9 ,:i* ! ,bolts ,d ,n ,pi]ce ! ,sp>4 99,trail+ ,edges994 ,^! are ei!r ( ?9 bevel$ a% or ,/eel tube4 ,on army ma*9es1 ! re> "p ( ! trail+ edge fabric is pi]c$ ) holes ab\t #c_/af in* diamet]1 ! holes be+ provid$ ) ru/ pro( eyelets4 ,?is relieves an excess ( pressure due to rips or te>s2 "o op5+ be+ locat$ betwe5 ea* rib & next to ! body4 ,illu/ration3 ,fig4 #ab;c4 ,a ,/&>d ,h-#c ,int]plane ,/rut ,socket ,is ,%[n at ! ,left1 ! ,bolts 9 ,?is ,case ,pass+ on ,ei!r ,side ( ! ,sp>4 ,note ! ,/ay ,wire ,atta*m5t ,clips & ,p9n$ ,/rut ,connection4 ,a ,g]man ,/rut ,socket at ,"r4 ,c\rtesy ,a]ial ,age4 99,protection ( ,w+ ,wood ,"w994 ,9 protect+ ! wood framework ( ! w+s f ! effects ( moi/ure1 at lea/ ?ree coats ( good sp> v>ni% %\ld be c>efully appli$1 ) an extra coat ov] ! glu$ surfaces & tap+4 ,%ellac is n suitable = ?is purpose4 ,x cracks ) ! deflection ( ! w+s & f9ally admits wat]4 ,! /eel p>ts ( ! w+ %\ld be giv5 two coats ( f9e lead pa9t1 & !n two coats ( sp> v>ni% ov] ! pa9t4 ,wires are treat$ ) "s flexible comp\nd1 z ! vibration ( ! ?9 wires1 or cables1 soon cracks (f any ord9>y v>ni%4 ,! use ( %ellac _c be too /rongly condemn$2 x is n only an indiff]5t protection1 b x causes ! fabric to rot :5 9 contact ) ! dop$ surface4 99,monoplane ,w+ ,sp>s994 ,a few repres5tative monoplane w+ sp>s are %[n by ,fig4 #ac1 ! ,r4 ,e4 ,p41 ,bl]iot ,,xi1 & ! ,nieuport4 ,except at po9ts :]e ! /ay wires are connect$1 ! ,bl]iot sp> is *annel$ out into ,i beam =m z indicat$ 9 ! figure4 ,x w be not$ t ! top & bottom faces ( ! sp> are slant$ to agree ) ! curvature ( ! ribs4 ,a4 /eel connection plate is bolt$ to ! sides ( ! sp> by ?r\gh bolts1 & ) a lug left top & bottom = ! top & bottom guy wires4 ,! ,r4 ,e4 ,p4 is also an ,i type1 ! section4 ,a be+ tak5 ?r\gh ! *annel$ portions1 :ile ,b is tak5 ?r\gh "o ( ! connection po9ts :]e ! beam is a solid rectangle4 ,! *annel+ %\ld always /op at connection po9ts2 fir/1 s t ! plates h a good be>+ surface1 & second1 to all[ = ! mat]ial remov$ by ! bolt holes4 ,illu/ration3 ,fig4 #ac4 ,typical ,monoplane ,w+ ,sp> ,con/ruction4 ,probably ! mo/ int]e/+ ( all ! sp>s is ! ,nieuport1 :i* is a comb9$ truss & gird] type4 ,?is sp> tap]s d[n f ! c5t] to bo? ends1 be+ ?icke/ at ! po9ts :]e ! guys are atta*$4 ,! top flange 7,j71 & ! bottom flange 7,l71 are a%1 :ile ! side plates & diagonals 7,h7 are spruce4 ,! diagonals resi/ ! %e>1 & are held 9 place by ! tie bolts 7,i74 ,at ! left1 ! spruce cov] plate is remov$1 :ile at ! "r x is 9 place ) ! int]ior con/ruction %[n 9 dott$ l9es4 ,! dim5sions are 9 millimet]s4 ,illu/ration3 ,fig4 #ad4 ,plate ,connection = ,monoplane ,/ay ,wire ,connection to ,sp>4 ,a ,compression ,memb] or ,drag ,/rut ,is ,%[n 9 ! ,c5t] ( ! ,sp> ,:i* ,takes ,up ! ,?ru/ ,due to ! ,angul>ity ( ! ,/ays & ,also ! ,drag ,/ress4 99,location ( ,sp>s994 ,!re are a numb] ( items t affect ! location ( ! sp>s 9 reg>d to ! lead+ edge4 ,! mo/ important factors 9 ! *oice ( location are3 7#a7 ,%ape & dep? ( w+ section1 7#b7 ,c5t] ( pressure movem5t1 7#c7 ,drag brac+ requirem5ts1 7#d7 ,wid? ( ail]ons1 7#e7 ,me?od ( atta*+ ! int]plane /ruts4 ,,*apt] ,,xi ,,fuselage 7,,body7 ,,con/ruction4 99,purpose ( ,fuselage994 ,! fuselage ( a monoplane or tractor biplane is ! backbone ( ! ma*9e4 ,x =ms a means ( connect+ ! tail surfaces to ! ma9 w+ surfaces1 c>ries ! motor1 fuel & pilot1 & transmits ! weight ( ^! items to ! w+s & *assis4 ,) ! exception ( ! w+ /ructure1 ! fuselage is ! mo/ important s+le item 9 ! con/ruction ( ! a]oplane4 ,fig4 #a %[s a typical arrangem5t ( a two-place biplane fuselage equipp$ ) a wat]-cool$ motor4 ,! motor ,e1 propell] ,y1 & radiator ,r are plac$ 9 ! front ( ! fuselage1 & consid]ably 9 advance ( ! w+s ,w & ,d4 ,imm$iately beh9d ! motor is ! pass5g]'s seat ,a & ! fuel tank ,f4 ,! pilot's seat ,b is plac$ beh9d ! trail+ edge ( ! w+s & is beh9d ! pass5g]'s seat4 ,! cockpit op5+s ,g & ,h are cut 9 ! fuselage top = ! pass5g] & pilot respectively4 ,! re> ext5sion ( ! fuselage c>ries ! control surfaces1 ,l be+ ! v]tical f91 ,m ! rudd]1 ,o ! fix$ tail or /abiliz]1 & ,p ! elevator4 99,resi/ance994 ,to r$uce ! resi/ance 9 flight1 ! fuselage is ( z p]fect /reaml9e =m z possible1 ! fuselage be+ deepe/ at a po9t ab\t "o-?ird f ! front4 ,f ?is po9t x tap]s out gradually to ! re>4 ,) ! motors n[ 9 use x is only possible to approximate ! ideal /reaml9e =m ow+ to ! front area ( ! radiator & to ! size ( ! motor4 ,aga91 ! projection ( ! pilot's head above ! fuselage adds consid]ably to ! resi/ance4 ,! w9d %ields ,i di/urb ! fl[ ( air4 ,! connections to ! tail surfaces & to ! *assis memb]s ,k also add to ! total resi/ance4 ,an ar*$ turtle deck ,j is g5]ally provid$1 ( su* a %ape t ! pilot's head is effectively /reaml9$1 ! tap] ( ?is deck all[+ ! di/urb$ air to close 9 gradually at ! re>4 ,! flat area pres5t$ by ! radiator ,r is probably ! greate/ s+le s\rce ( resi/ance1 & = ?is reason ! radiator is sometimes plac$ at ! side ( ! fuselage1 or 9 "s o!r position t w all[ ( a bett] front end outl9e4 ,an example ( ?is con/ruction is %[n by ,fig4 #b 9 :i* ! radiator ,r is plac$ beh9d & above ! motor ,e4 ,! front fuselage end ,z c n[ be made ( a m suitable /reaml9e =m4 ,illu/ration3 ,figs4 #a-b-c4 ,fuselage & ,motor ,arrangem5t ( ,tractor ,biplanes4 ,fig4 #c is a view ( ! front end ( a typical fuselage 9 :i* an air-cool$ rot>y type ( motor is in/all$4 ,s9ce ! diamet] ( ?is type ( motor is seldom mu* less ?an ?ree feet1 x is necess>y to h a v great diamet] 9 ! extreme front4 ,! motor h\s+ or c[l m>k$ ,e has a diamet] d :i* %\ld smoo?ly bl5d into ! outl9e ( ! fuselage at b4 ,9 ! old] types ( con/ruction !re 0 (t5 a v consid]able break 9 ! outl9e at ?is po9t1 especially 9 cases :]e ! circul> c[l 0 abruptly connect$ to a squ>e fuselage4 ,a break ( ?is sort greatly increases ! head resi/ance4 ,a sp9n] or propell] cap m>k$ ,z 9 ,fig4 #c is an aid 9 r$uc+ ! resi/ance (f]$ by ! motor c[l & also r$uces ! resi/ance ( ! inn]1 & ineffective1 portion ( ! propell] blades4 ,! cap 9 any case is small] ?an ! c[l op5+ 9 ord] t cool+ air be admitt$ to ! enclos$ cyl9d]s4 99,di/ribution ( ,loads994 ,return+ to ,fig4 #a1 we note t ! weight ( ! fuselage1 pilot1 pass5g]1 fuel1 control surfaces & motor are c>ri$ to ! upp] w+ ,w by ! cabane /rut memb]s ,c-,c & /ays1 ! l[] w+ be+ connect$ directly into ! sides ( ! fuselage4 ,cont9uations ( ! cabane memb]s on ! int]ior ( ! fuselage int]-connect ! upp] & l[] w+s 7%[n 9 dott$ l9es74 ,! int]plane /ays 9 connection ) ! cabane memb]s b9d ! w+s & fuselage into a unit4 ,a v]tical l9e ,,cp passes ?r\gh ! c5t] ( pressure ( bo? w+s1 & approximately ?r\gh ! c5t] ( gravity ( ! ma*9e4 ,9 o!r ,words1 ! ma*9e is ne>ly balanc$ on ! c5t] ( pressure l9e4 ,! turn+ mom5ts ( weights beh9d ! ,,cp mu/ approximately balance ! opposite turn+ mom5ts ( ! masses locat$ 9 front ( ! ,,cp4 ,! exact relation betwe5 ! c5t] ( pressure & ! c5t] ( gravity w be tak5 up lat]4 ,v>iable loads su* z ! pass5g]1 gasol9e & oil1 are plac$ z ne>ly z possible on ! c5t] ( pressure l9e1 s t v>iation 9 ! weight w n affect ! balance4 ,9 ! figure1 ! pass5g]'s seat ,a1 & ! fuel tank ,f are on ! ,,cp l9e1 or ne>ly s4 ,?us1 a r$uction 9 ! weight ( ! fuel w n affect ! trim ( ! ma*9e1 nor w a wide v>iation 9 ! weight ( ! pass5g] produce any su* effect4 ,z %[n1 ! pass5g]'s seat is plac$ directly on ! top ( ! fuel tank1 an arrangem5t widely us$ by ,european con/ructors4 ,9 ! majority ( ,am]ican ma*9es ! fuel tank is plac$ at ! top ( ! fuselage in/ead ( 9 ! position illu/rat$4 ,z ! pilot is consid]$ z a con/ant weight1 8 location does n affect ! balance4 ,:5 at re/ on ! gr\nd1 ! weight ( ! re> end ( ! fuselage is support$ by ! tail skid ,n4 ,! l5g? ( ?is skid mu/ be su* t ! tail surfaces are kept well cle> ( ! gr\nd4 ,! c5t] ( ! *assis :eel ,q is plac$ 9 front ( ! c5t] ( gravity s t ! weight ( ! ma*9e w cause ! tail skid to be> on ! gr\nd :5 ! ma*9e is at re/4 ,if ! :eel 7 beh9d ! c5t] ( gravity1 ! ma*9e w\ld /& on its nose :5 mak+ a l&+4 ,! :eels mu/ be locat$ s t ! t5d5cy to nose ov] is z small z possible1 & yet mu/ n be set s f> =w>d t !y w cause an excessive load on ! tail skid4 ,) too mu* load on ! skid1 ! tail w n come up1 except aft] fa/ & prolong$ runn+1 & heavy /resses w be set up 9 ! framework due to ! tail bump+ ov] ! gr\nd at high spe$4 ,! skids %\ld n be dragg$ fur!r ?an absolutely necess>y1 especially on r\gh gr\nd4 ,) prop] weight & :eel adju/m5t1 ! tail %\ld come up 9 a %ort run4 ,! :eel adju/m5t w be tak5 up "u ! head ( ,*assis4 99,position 9 ,flight994 ,9 normal horizontal flight1 ! c5t] l9e ( ?ru/ ,,ct is horizontal or ne>ly s4 ,?is l9e ( ?ru/ passes ?r\gh ! c5t] ( ! motor crank%aft & propell]4 ,9 an upw>d climb1 ! ,,ct is incl9$ at ! angle ( climb1 & s9ce ! ,,ct indicates ! l9e ( flight1 ! /reaml9e curves ( ! body %\ld be laid out s t ! axis ( lea/ body resi/ance w co9cide ) ! l9e ( ?ru/4 ,:5 fly+ horizontally at ! normal spe$1 ! body mu/ pres5t ! m9imum ( resi/ance & ! w+s mu/ be at ! mo/ effici5t angle ( incid5ce4 ,9 climb+1 or fly+ at a v l[ spe$1 ! tail mu/ necess>ily be depress$ to ga9 a l>ge angle ( w+ incid5ce1 & h5ce ! body resi/ance w be comp>atively high ow+ to ! angle ( ! body ) ! flight l9e4 ,x is be/ to h ! lea/ resi/ance ( ! fuselage co9cide ) ! normal horizontal flight spe$4 ,?is condition at once e/abli%es ! angle ( ! w+s 9 reg>d to ! fuselage c5t] l9e4 99,c5t] ,l9e ( ,resi/ance994 ,! c5t] l9e ( ?ru/ %\ld pass ?r\gh ! c5t] ( total head resi/ance z ne>ly z possible4 ,! total resi/ance ref]r$ to is compos$ ( ! w+ drag1 body & *assis resi/ances4 ,9 an ord9>y milit>y type ( a]oplane ?is l9e is locat$ approximately at "o-?ird ( ! gap f ! bottom w+4 ,ow+ to v>iations 9 ! drag ( ! ,w+s at diff]5t angles1 ?is po9t v>ies "u diff]5t fly+ conditions1 & aga91 x is affect$ by ! =m & size ( ! fuselage & *assis4 ,! exact location ( ! c5t] ( resi/ance involves ! computation ( all ( ! resi/ance produc+ items4 ,9 addition to pass+ ?r\gh ! c5t] ( resi/ance1 ! c5t] l9e ( ?ru/ %\ld pass slightly bel[ ! c5t] ( gravity ( ! ma*9e4 ,9 ?is position ! pull ( ! motor t5ds to hold ! head up1 b 9-case ( motor failure ! ma*9e imm$iately t5ds to head-dive & ?us to increase its spe$4 ,! t5d5cy to dive ) a dead motor automatically ov]comes ! t5d5cy to /all or to lose headway4 ,) ! c5t]l9e ( ?ru/ det]m9$1 & ) giv5 motor dim5sions1 ! fuselage position c be locat$ at once 9 reg>d to ! w+s4 ,?is is good en\gh = a prelim9>y lay\t1 b mu/ be modifi$ 9 ! f9al design4 ,z be=e expla9$1 ! c5t]l9e ( ?ru/ is locat$ at a po9t betwe5 ! two w+s1 approximately "o-?ird ( ! gap f ! l[] w+4 ,9 ma*9es hav+ a span ( #ce feet & ov]1 x is a trifle less ?an "o-?ird ! gap1 :ile 9 small spe$ sc\ts x is g5]ally a trifle ov] "o-?ird4 ,?is rule *ecks v closely ) ! data obta9$ f #bb /&>d ma*9es4 ,?us1 9 a ma*9e hav+ a #f-;foot gap1 ! propell] c5t]l9e w be locat$ ab\t #b feet above ! l[] w+4 ,! top ( ! fuselage 7measur$ "u ! /abiliz] surface7 is f #e to #h in*es above ! c5t] l9e ( ?ru/4 ,at ! motor end1 ! height ( ! fuselage above ! ,,ct is controll$ by a numb] ( factors1 ei!r by ! type ( motor1 or by ! arrangem5ts made = access to ! motor p>ts4 ,9 a numb] ( ,european ma*9es1 ! motor sits well above ! top ( ! fuselage1 ?is always be+ ! case :5 a six-cyl9d]1 v]tical wat]-cool$ motor is us$4 ,) an air-cool$ type1 ! top is gov]n$ by ! c[l diamet]4 99,motor ,comp>tm5t994 ,! space occupi$ by ! motor & its accessories is kn[n z ! motor comp>tm5t1 & 9 monoplane & tractor biplane fuselage x is locat$ 9 ! extreme front ( ! body4 ,! int]ior arrangem5t v>ies ) diff]5t types ( motors & makes ( ma*9es4 ,) rot>y cyl9d] motors1 ! comp>tm5t is (t5 no?+ b a metal c[l1 :ile ) l>ge wat]-cool$ motors x occupies a consid]able portion ( ! body4 ,wat]-cool$ motors are g5]ally cov]$ ) automobile type hoods1 ^! usually be+ provid$ ) gill$ op5+s = v5tilation4 ,ow+ to ! heat g5]at$ 9 ! motor1 "s sort ( v5tilation is imp]ative at ?is po9t4 ,:atev] ! type1 ! comp>tm5t is always cut (f f ! re/ ( ! fuselage by a firepro( metal p>tition to gu>d aga9/ fire rea*+ ! pass5g] or fuel tanks4 ,! fuel & oil %\ld always be sep>at$ f ! motor by sub/antial p>titions s9ce a s+le c>buret] pop may cause s]i\s tr\ble4 ,illu/ration3 ,fig4 #d4 ,m\nt+ & ,c[ls = ,rot>y ,cyl9d] ,motors4 ,c\rtesy ,flight4 ,accessibility is a mo/ important feature 9 ! design ( ! motor end1 & h5ce ! hood %\ld be ( ! h+$ automobile type s t x c be easily rais$ = inspection or repairs4 ,9 ! ,curtis ,,jn#d-;,b ,milit>y ,tra9+ ,tractor1 ! cyl9d] heads & valve me*anism project slightly above ! top ( ! hood s t ^! p>ts are amply cool$ & are entirely accessible4 ,access to ! c>buret] c be _h ?r\gh a small h&-hole 9 ! side ( ! hood4 ,! radiator 9 ?is ,curtiss model is locat$ 9 ! extreme front end ( ! fuselage--automobile fa%ion4 ,! propell] %aft passes ?r\gh a c5tral op5+ 9 ! radiator4 ,9 ,fig4 #f ! v]tical motor ,e is set d[n l[ 9 ! frame1 ! upp] "p ( ! fuselage ,f end+ at ,h4 ,! eng9e be>] ,b1 :i* c>ries ! motor1 =ms ! top "p ( ! fuselage at ?is po9t4 ,! eng9e is ?us 9 ! cle> & access c easily be _h to e "p ( ! motor4 ,! radiator is 9 front ( ! motor at ,r4 ,:5 9 flight ! motor is cov]$ by a %eet metal hood simil> to ! fold+ hood us$ on automobiles4 ,?is type is us$ 9 ! ,m>t91 ,/urtevant1 & sev]al ,european ma*9es4 ,illu/ration3 ,fig4 #e4 ,motor ,comp>tm5t ( a ,curtiss ,tractor ,biplane ,us+ a ,front ,type ,radiator4 ,note ! ,two ,exhau/ ,pipes ,:i* ,c>ry ! ,gases ,ov] ! ,top ( ! ,w+s4 ,fig4 #g is a v common front end arrangem5t us$ ) side radiators4 ,! top fuselage memb] ,f is br\ght d[n 9 a v l[ curve1 leav+ ! great] "p ( ! motor project+ above ! fuselage4 ,at ! extreme front1 ! upp] fuselage memb] ,f jo9s ! eng9e be>] ,b1 ! connection be+ made ) a press$ /eel plate4 ,! radiator ,r is %[n at ! side ( ! fuselage4 ,! cyl9d]s are n usually cov]$ :5 9 flight4 ,9 ! front view x w be not$ t ! radiators are arrang$ on ei!r side ( ! fuselage4 ,a side view ( ! ,h4 & ,m4 ,f>man ,fight] is %[n by ,fig4 #aj4 ,?is is a v effici5t ,fr5* ma*9e :i* has se5 mu* active s]vice 9 ! w>4 ,! front end is mu* l t %[n 9 ,fig4 #g except t a sp9n] cap is fitt$ to ! propell] boss4 ,a ,v type motor all[s ( ! radiator be+ m\nt$ betwe5 ! two r[s ( cyl9d]s1 & 9 a position :]e x w cause ! lea/ possible head resi/ance4 ,illu/ration3 ,figs4 #f-g4 ,v>i\s ,motor ,arrangem5ts1 & ,radiator ,locations4 ,illu/ration3 ,fig4 #aj4 ,a ,type ( ,h4 & ,m4 ,f>man ,tractor ,fight+ ,biplane4 ,?is ,ma*9e ,uses a ,v4 ,type ,motor1 ) ! ,radiator 9 ! ,valve ,alley4 ,! ,gunn] & ! ,ma*9e ,gun ,are ,m\nt$ 9 ! ,re> ,cock-pit4 ,x ,w ,be ,not$ ,t ! ,body ,is ,rais$ ,well ,above ! ,l[] ,w+ ,s t ! ,gun ,field ,is ,increas$4 ,! ,pilot ,is ,well ,ahead ( ! ,ent]+ ,edge ( ! ,l[] ,w+4 ,c\rtesy ( ,a]ial ,age4 ,! fuselage is ( excell5t /reaml9e =m & %[s c>eful /udy 9 reg>d to ! arrangem5t ( ! p[] plant4 ,unlike ! majority ( ma*9es1 ! fuselage is rais$ well above ! bottom w+1 ?is be+ done evid5tly to increase ! range ( ! gun 9 ! re> cockpit4 ,! increas$ height all[s ! gun to %oot ov] ! top plane at a fairly small angle1 & ! height above ! gr\nd p]mits ! use ( a v l>ge & effici5t propell] )\t hav+ an excessively high *assis4 ,at ! re> ! fuselage tap]s d[n to a v ?9 knife edge & !re=e produces little di/urbance4 ,illu/ration3 ,fig4 #aa4 ,radiator ,m\nt$ at ,lead+ ,edge ( ,upp] ,w+4 ,?is ,type ,is ,us$ ) ! ,/urtevant & ,lawson ,a]oplanes & ,is ,v ,effective ,because ( ! ,improv$ ,circulation4 ,fig4 #aa %[s a ,/urtevant ,tra9+ ,biplane 9 :i* ! radiator is m\nt$ at ! front edge ( ! upp] plane4 ,?is arrangem5t 0 orig9ally introduc$ by ! ,/urtevant ,company 9 _! /eel biplanes & has prov$ a v effici5t type = cool+1 al?\gh ! radiator mu/ affect ! lift ( ! top plane to a v consid]able ext5t4 99,pilot & ,pass5g] ,comp>tm5ts994 ,^! comp>tm5ts conta9 ! seats1 controls1 & in/rum5ts1 & 9 ! milit>y types conta9 ! gun m\nts & ammunition4 ,9 "s battle-planes1 ! pass5g] or obs]v] occupies ! re> seat1 z ?is position gives a wid] range ( fire aga9/ re> or side attacks4 ,?is arrangem5t is true ( ! ,h4 & ,m4 ,f>man ma*9e j illu/rat$ & describ$4 ,9 ! l>ge ,g]man ,go?a ! gunn] occupies ! re> position & fires ?r\gh1 or above1 a tunnel built ?r\gh ! re> end ( ! fuselage4 ,9 "s =ms ( tra9+ ma*9es1 ! pilot & pass5g] sit side by side in/ead ( 9 t&em1 z ?is arrangem5t all[s bett] communication betwe5 ! pilot & /ud5t1 & p]mits ! =m] to keep bett] wat* ov] ! movem5ts ( ! /ud5t4 ,a notable example ( ?is type is ! ,burgess ,prim>y ,tra9]4 ,a side-by-side ma*9e mu/ h a v wide fuselage & !re=e pres5ts m head resi/ance ?an "o ) ! seats arrang$ 9 t&em1 b ) prop] att5tion to ! /reaml9e =m ?is c be r$uc$ s t ! loss is n z s]i\s z w\ld be imag9$ f a view ( ! lay\t4 ,! seats may be ( sev]al types1 7a7 ! alum9um bucket type simil> to1 b light] ?an1 ! bucket seats us$ 9 rac+ automobiles2 7b7 ! wov5 wick] seat us$ 9 _m types ( ,g]man ma*9es1 or 7c7 ! modifi$ *air =m ) wood5 side rails & tightly /ret*$ lea!r back & bottom4 ,:atev] ! type1 !y %\ld be made z com=table z possible1 s9ce ! op]ation ( a heavy ma*9e is try+ en\gh )\t add+ additional discom=t 9 ! =m ( flimsy h>d seats4 ,9 ! old] ma*9es ! seats 7 no?+ m ?an p]*es on :i* ! pilot balanc$ himself prec>i\sly & 9 int5se discom=t4 ,a few p\nds add$ 9 ! =m ( a com=table seat is mat]ial well sp5t s9ce x is a great factor 9 ! effici5t op]ation ( ! ma*9e4 ,wick] seats are light1 yield+ & com=table1 & c be made z /rong or /rong] ?an ! o!r types4 ,x seems /range t !y h n be5 m widely adopt$ 9 ?is c\ntry4 ,all seats %\ld be slightly tilt$ back s t ! pilot c lean back 9 a com=table position1 ) a c]ta9 portion ( 8 weight aga9/ ! back ( ! seat4 ,sitt+ 9 a rigid v]tical position is v tir+1 & is especially s :5 fly+ 9 r\gh wea!r1 or on long reconnaissance trips4 ,! backs ( ! seats %\ld be high & head re/s %\ld be provid$ s t ! pilot's head c be com=tably support$ aga9/ ! pressure ( ! w9d4 ,if ^! head re/s are /reaml9$ by a long1 tap]+1 project+ cone runn+ back along ! top ( ! fuselage1 ! resi/ance c be consid]ably r$uc$4 ,?is arrangem5t 0 fir/ introduc$ 9 ! ,gordon-,b5nett ,dep]duss9 & has be5 foll[$ 9 _m mod]n ma*9es4 ,9 ! ,dep]duss91 ! pilot's head 0 expos$ directly to ! full bla/ ( ! propell] slip/ream & a head support 0 c]ta9ly ne$$4 ,small1 transp>5t w9d %ields are n[ fa/5$ to ! front edge ( ! cockpit op5+s :i* to a c]ta9 ext5t %ield ! pilot f ! t]rific w9d pressure4 ,^! are q l[ & pres5t little resi/ance at high spe$s4 ,illu/ration3 ,fig4 #ab4 ,hall-,scott ,motor & ,side ,type ,radiator ,m\nt+ on a ,typical ,tractor4 ,a heavy lea!r cov]$ pad1 or roll1 %\ld be run entirely ar\nd ! edge ( ! cockpit op5+ z a protection to ! pilot 9 case ( an accid5t or h>d l&+4 ,! roll %\ld be at lea/ #c #a_/b 9 diamet] & %\ld be fill$ ) horse hair4 ,all %>p edges 9 ! cockpit %\ld be simil>ly gu>d$ s t 9 ! ev5t ( ! pilot be+ ?r[n out ( 8 seat1 he w n be cut or bruis$4 ,ea* seat %\ld be provid$ ) an improv$ safety /rap t w securely hold ! pilot 9 8 seat1 & yet mu/ be arrang$ s t x c be quickly & easily releas$ 9 an em]g5cy4 ,9 flight ! occupants mu/ be securely /rapp$ 9 place to prev5t be+ ?r[n out dur+ rapid maneuv]s or 9 r\gh wea!r4 ,buckles %\ld be sub/antial & well sew$ & rivet$ to ! fabric s t !re w be no dang] ( _! be+ torn out4 ,! /raps mu/ be arrang$ s t !y w n int]f]e ) ! free movem5t ( ! pilot1 & s t !y w n become entangl$ ) ! controls4 ,x is be/ to copy ! sets approv$ by ! gov]nm5t z ^! are ! result ( long cont9u$ exp]im5t & use4 ,illu/ration3 ,fig4 #ac4 ,dep]duss9 ,monoplane ) ,monocoque ,body4 ,note ! ,/reaml9e ,=m ( ! ,body & ! ,sp9n] ,cap at ! ,root ( ! ,propell]4 ,c>e mu/ be tak5 to h ! seats locat$ at ! correct height f ! floor s t ! legs w n become cramp$4 ,9 ! majority ( ma*9es1 ! v]tical rudd] is op]at$ by ! feet4 ,unless ! seat is at ! prop] height1 ! pilot w be 9 a /ra9$ position z he _c %ift ar\nd nor take 8 feet f ! rudd] b>4 ,ei!r ! rudd] b> or ! seat %\ld be adju/able = diff]5t l5g?s ( legs4 ,usually ! adju/m5t is made 9 ! rudd] b> s9ce x is n usually advisable to %ift ! seats ow+ to ! necessity ( hav+ ! pilot's weight 9 a fix$ position4 ,9 "s old types ( monoplanes1 ! pilot sat on a small pad plac$ on ! floor ( ! fuselage4 ,ne$less to say1 ?is 0 a horribly uncom=table position to be 91 b z ! flights ( t "t 7 ( %ort duration x did n matt] mu*4 ,if ! feet c\ld be remov$ occasionally f ! rudd] b> ! matt] ( seat position w\ld n be ( s mu* importance1 b to sit flat on ! floor1 ) ! legs /raight out1 = a c\ple ( h\rs is a t]rible /ra9 & has und\bt$ly caus$ _m accid5ts ?r\gh cramps4 ,z bo? ! pass5g] & ! fuel are v>y+ weights1 ! fuel tank seat idea is good4 ,?is all[s bo? ( ^! items to be plac$ at ! c5t] ( gravity ( ! ma*9e :]e weight v>iation w h no effect on ! balance ( ! plane4 ,9 ?is position1 h[ev]1 ! fuel mu/ be pump$ up to a high] auxili>y tank s9ce ! ma9 tank w\ld be too f> bel[ ! c>buret] = gravity fe$4 ,! floor+ ( ! cockpits c be ei!r ( v5e]1 or c be built up ( small spruce slats ab\t #a_/b x #a_/b1 ! slats be+ spac$ ab\t #a_/b ap>t4 ,! latt] floor is specifi$ by ! gov]nm5t = seaplane use1 & is v light & desirable4 ,! floor is plac$ only at po9ts :]e x w be /epp$ on4 ,obs]vation holes are cut 9 ! floor on a l9e ) ! edge ( ! seats s t ! occupants c view ! gr\nd )\t look+ ov] ! edge ( ! fuselage4 ,! obs]vation port holes are ab\t #i in*es 9 diamet]4 ,glass %\ld nev] be us$ 9 ! cockpits except = ! in/rum5t cov]s1 unless x is ( ! non-spl9t]+ triplex lam9at$ type ( glass4 ,! use ( inflammable celluloid %\ld also be avoid$ z be+ ev5 m dang]\s ?an ! glass4 ,! triplex glass is built up ( two or m lay]s ( glass1 :i* are cem5t$ toge!r ) a celluloid film appli$ "u heavy pressure4 ,?is =m ( con/ruction is v /rong1 & :ile x c be brok51 x w n fly ap>t 9 ! =m ( spl9t]s4 ,all in/rum5ts %\ld be plac$ directly 9 front ( ! pilot s t he c take obs]vations )\t turn+ 8 head4 ,usually all ( ! in/rum5ts1 ) ! exception ( ! compass1 are m\nt$ on a s+le in/rum5t bo>d plac$ 9 front ( ! pilot & directly "u ! =w>d edge ( ! cockpit op5+4 ,! compass c be plac$ on ! floor z 9 ,am]ican ma*9es1 or ins]t$ 9 ! upp] w+ z 9 "s ,european ma*9es4 ,! motor control app>atus is plac$ :]e x c be rea*$ conv5i5tly f ! seat4 ,oil gages1 gasol9e gages1 & revolution c\nt]s are g5]ally plac$ on ! in/rum5t bo>d :]e !y c be easily obs]v$4 ,if a wireless set is c>ri$1 ! swit*es are plac$ on1 or ne>1 ! in/rum5t bo>d4 ,ow+ to ! uses to :i* ! diff]5t ma*9es are put x is impossible to give a li/ ( in/rum5ts t w\ld be suitable = e ma*9e4 ,! simple/ ma*9e %\ld h ! foll[+ in/rum5ts3 99,altimet]99 = measur+ altitude4 99,clock99 ( special a]oplane type4 99,incid5ce indicator499 99,air spe$ indicators99 = measur+ ! spe$ ( ! ma*9e relative to ! air4 99,gasol9e1 oil & pressure gages99 = det]m9+ am\nt ( fuel4 ,in/rum5ts = ,navy & ,army ma*9es are ( c\rse m complete4 ,9 ! specifications = ,army ,hydroa]oplanes 7tw9 motor type #aiaf7 ! foll[+ in/rum5ts are specifi$3 99,an]oid ,b>omet]994 ,graduat$ 9 feet1 & read+ f sea-level to #ab1jjj feet4 99,compasses994 ,"o 9 ea* cockpit4 ,to be ( ! ,sp]ry ,gyroscopic type ) an ela/ic susp5sion & prop]ly damp$4 ,%all be atta*$ to1 & syn*roniz$ )1 ! gr\nd drift indicator4 99,gr\nd ,drift ,indicator994 ,locat$ 9 obs]v]'s cockpit4 ,= not+ drift due to side w9ds4 ,see illu/ration on page #bdd4 99,clock994 ,special a]oplane type1 built to resi/ vibration4 ,locat$ 9 pilot's cockpit4 ,illu/ration3 ,fig4 #ad4 ,a]oplane ,compass ( ! ,mc,creagh-,osborn ,type4 7,sp]ry7 99,gasol9e ,supply ,gage994 ,to indicate ! am\nt ( fuel 9 gravity s]vice tank at all attitudes ( flight1 & %all be visible f pilot's seat4 ,a gage 9 ! ma9 tank w also be desirable t w regi/] ! approa*+ exhau/ion ( fuel4 ,?is indicator %\ld regi/] :5 #ge ( ! fuel 9 ! ma9 tank is exhau/$1 & !n record ! rema9d] cont9u\sly4 99,air ,spe$ ,indicator994 ,"o 9 pilot's cockpit4 99,angle ( ,incid5ce ,indicator994 ,sp]ry type4 ,to be locat$ 9 pilot's cockpit4 99,incl9omet]994 ,= measur+ angle ( incl9ation ( longitud9al axis ( ma*9e4 ,9 pilot's cockpit1 & plac$ on in/rum5t bo>d 9 ! vic9ity ( ta*omet]s4 99,bank ,indicator994 ,= indicat+ ! prop] am\nt ( bank on turns4 ,9 pilot's cockpit4 99,map ,bo>d994 ,"o revolv+ map bo>d plac$ 9 pilot's cockpit4 99,map ,desk994 ,"o fold+ map desk 9 obs]v]'s cockpit4 ,illu/ration3 ,fig4 #ae4 ,sp]ry ,gr\nd ,drift ,indicator4 99,ta*omet]s994 ,= measur+ spe$ ( motors 9 revolutions p] m9ute4 ,pilot's cockpit4 99,self-,/>t] ,swit*994 ,= op]at+ self-/>t]4 ,on in/rum5t bo>d 9 pilot's cockpit4 ,among ! o!r accessories specifi$ 9 ! cockpit = ! above ma*9es are a ,pyr5e fire ext+ui%]2 a #b-;gallon wat] break]2 a speak+ tube = communication betwe5 ! pilot & obs]v] 7#a to #a #a_/h72 a fla%light signal = speak+ tube2 & a tool kit4 ,! weight ( ! tool kit %all n exce$ #aa lbs4 ,illu/ration3 ,fig4 #af4 ,cock-pit ( a ,london & ,prov9cial ,biplane4 ,control ,lev] 9 ,=egr\nd & ,in/rum5t ,bo>d ,"u ,c[l4 ,c\rtesy ( ,flight4 99,g5]al ,proportions ( ! ,fuselage994 ,! total l5g? ( ! fuselage dep5ds ^u ! type ( p[] plant1 ^u ! span or *ord ( ! w+s1 & ^u ! arrangem5t ( ! tail surfaces4 ,! re> end ( ! fuselage %\ld be f> en\gh away f ! w+s to insure t ! re> surfaces are n unduly affect$ by ! d[n-wa% or ! wake-/ream ( ! w+s4 ,a v %ort fuselage gives a %ort lev] arm to ! control surfaces1 h5ce ^! surfaces mu/ be v l>ge ) a %ort body4 ,) ! /abiliz] surface close to ! w+s1 ! damp+ effect is slight1 t is1 ! surface does n effectively kill or damp d[n oscillations4 ,l>ge tail surfaces are heavy1 difficult to brace1 & cause a v consid]able am\nt ( head resi/ance4 ,! extra weight ( a long fuselage is g5]ally (fset by ! increas$ weight caus$ by ! l>ge tail area ( ! %ort body type4 ,:5 ma*9es are crat$ & %ipp$ at frequ5t int]vals1 a v long fuselage is objectionable unless x is built 9 two sections4 ,x also requires mu* /orage space & a v long hang>4 ,ma*9es = private use mu/ (t5 be sacrific$ f ! effici5cy /&po9t 9 ord] to keep ! dim5sions )9 reasonable limits4 ,an a]oplane requir+ an enorm\s hang> has c]ta9ly no attraction = ! av]age man4 ,e ef=t mu/ be made to cond5se ! ov]all dim5sions or to arrange ! extremities s t !y c be easily dism\nt$4 ,exhibition fly]s require specially portable ma*9es s9ce !y %ip !m ne>ly e day1 & ! exp5se ( h&l+ a long awkw>d fuselage may alone det]m9e ! *oice ( a plane4 ,x is usually be/ to divide ! body at a po9t j to ! re> ( ! pilot's seat1 al?\gh _m fly]s look ^u a two-"p body ) disfavor unless !y c be %[n t ! jo9t connections are z /rong z ! re/ ( ! fuselage4 ,illu/ration3 ,fig4 #ai4 ,fuselage ,dim5sion ,*>t = ,two ,place ,a]oplane ,fuselage4 ,upp] ,diagram ,is ! ,wat] ,cool$ ,type & ! ,l[] ,figure ,applies to a ,ma*9e ) a ,rotat+ ,air ,cool$ ,motor4 ,see ,table ( ,dim5sions on ,page #bdh4 ,z a guide 9 ! *oice ( fuselage proportions1 a set ( diagrams & a table are atta*$ :i* gives ! g5]al ov]all dim5sions ( sev]al prom95t makes ( ma*9es4 ,! lett]s 9 ! diagram ref] to ! lett]s head+ ! columns 9 ! tables s t ! g5]al dim5sions ( any "p c be readily det]m9$4 ,i d n claim t ^! dim5sions %\ld be foll[$ religi\sly 9 e case1 b !y %[ :at has be5 done 9 ! pa/ & w at lea/ sugge/ ! limits )9 :i* a new ma*9e c be built4 ,illu/ration3 ,fig4 #bj4 ,fuselage ,dim5sion ,diagrams ,giv+ ! ,pr9cipal ,dim5sions ( ,spe$ ,sc\t ,ma*9es4 ,upp] ,figure ,%[s ,typical ,sc\t ) ,wat] ,cool$ ,motor 7,curtiss71 ,:ile ,l[] ,diagram ,%[s an ,arrangem5t ,common ) ,rot>y ,air ,cool$ ,motors 7,nieuport7 ,fig4 #ai gives ! outl9e & dim5sion lett]s = two-place ma*9es ( :at is kn[n z ! ,reconnaissance ,type4 ,bo? wat]-cool$ & air-cool$ motor equipm5ts are %[n1 ! top ma*9e be+ ( ! wat]-cool$ type :ile ! l[] figure %[s a typical two-place ma*9e ) a rot>y air-cool$ motor4 ,und]nea? ?is side elevation is a front view ( ! fuselage1 & a section tak5 ?r\gh ! po9t ( greate/ dep?4 ,z %[n1 ! fuselage is ( squ>e cross-section1 b ! dim5sion ,b applies equally to ! diamet] ( a circul> cross-section4 ,dim5sion ,c gives ! height ( ! curv$ upp] deck1 or turtle deck ( ! fuselage4 ,dim5sion ,d %[s ! extreme l5g? ext5d+ 9 front ( ! lead+ edge ( ! l[] w+1 & ,t %[s ! l5g? ( ! re> portion back ( ! lead+ edge ( ! l[] w+1 ! lead+ edge be+ tak5 z a base ( measurem5t4 ,! location ( ! deepe/ section1 measur$ f ! extreme front ( ! fuselage1 is giv5 by ,e1 ! dep? at ?is po9t be+ indicat$ by ,b4 ,! extreme wid? is %[n by ,i4 ,9 ! ma*9e %[n1 side radiators are us$1 ! blunt front end dim5sion$ by ,g & ,k be+ ! dim5sion ( ! front eng9e plate4 ,:5 front radiators are us$1 ! dim5sions ,g & ,k also apply to ! size ( ! radiator4 ,! am\nt ( advance1 or ! di/ance ( ! *assis :eel c5t] f ! lead+ edge is giv5 by ,s1 & ! di/ance ( ! :eel c5t] bel[ ! lead+ edge is giv5 by ,r4 ,v is ! l5g? ( ! eng9e project+ above ! fuselage top4 ,! pass5g] or obs]v] is indicat$ by #a & ! pilot by #b4 ,! top plane is #c & ! bottom plane #d4 ,! eng9e is locat$ by #e1 & ! top fuselage-rail1 or long]on1 by #g4 ,turtle deck is #f4 ,illu/ration3 99 ,r\nd monocoque body1 dim5sions 7,b7 & 7,f7 measur$ f out] diamet] or top ( circle ,fig4 #bj gives ! diagrams ( spe$ sc\t ma*9es1 bo? ( ! air-cool$ & wat]-cool$ types4 ,^! are ! small1 fa/1 s+le seat ma*9es s mu* us$ 9 ! ,european w> = repell+ air attacks & = gu>d+ ! l>g] & sl[] bomb+ & obs]vation ma*9es4 ,! upp] draw+ %[s a ,curtiss ,spe$ ,sc\t equipp$ ) a ,v type wat]-cool$ motor & a circul> front radiator4 ,:ile ! front ( ! body is circul>1 x gradually fades out into a squ>e cross-section at ! re>4 ,! l[] ma*9e is a ,nieuport spe$ sc\t equipp$ ) a rotat+ cyl9d] air-cool$ motor4 ,9 ?is sc\t1 ! diamet] ( ! motor c[l is giv5 by dim5sion ,k4 ,body is ( squ>e cross-section4 ,x w also be not$ t ! *ord ( ! l[] plane is less ?an t ( ! upp] plane & t ! deep body almo/ entirely fills ! gap betwe5 ! two w+s4 ,illu/ration3 ,fig4 #ba4 ,curtiss ,j ,n #d-;,b ,fuselage ,box$ = ,%ipm5t4 ,) "s ( ! lat] spe$ sc\ts1 ! body entirely fills ! gap betwe5 ! w+s & ! top plane is fa/5$ directly to ! top memb]s ( ! fuselage4 ,?is makes w9d[s necess>y 9 ! sides ( ! fuselage4 ,:5 v]tical wat]-cool$ motors are us$ on spe$ sc\ts1 ! front view is entirely cut (f1 = ^! are v l>ge motors & project above ! fuselage = a consid]able di/ance4 ,?is ob/ruction is avoid$ 9 ! ,curtiss spe$ sc\t %[n1 by ! use ( a ,v type motor4 ,x w be not$ t ^! two sc\ts1 especially ! ,nieuport1 are ( excell5t /ream l9e =m1 a v important item ) su* high spe$ ma*9es4 ,! propell] ( lat] ,nieuports is provid$ ) a conical sp9n] cap :i* evid5tly r$uces ! head resi/ance to a consid]able ext5t4 ,! diff]5t portions ( ! ma*9e are indicat$ by ! same figures z 9 ! case ( ! reconnaissance ma*9e4 ,,*apt] ,,xii ,,details ,,( ,,fuselage ,,con/ruction ,classification ( types4 ,:ile !re are a numb] ( me?ods adopt$ 9 build+ up ! fuselage /ructure1 ! common type is ! wire truss 9 :i* wood compression memb]s are us$ 9 connection ) /eel wire or cable t5sion memb]s4 ,f\r wood5 long]ons or longitud9als run ! entire l5g? ( ! body & are b5t to its g5]al outl9e4 ,! longitud9als are spac$ at ! correct di/ance by wood compression memb]s1 :i* 9 turn are held 9 place by wire cross brac+4 ,?is me?od ( truss+ =ms a v /rong & light /ructure1 al?\gh r complicat$1 & difficult to build4 ,! cross-section is rectangul>1 al?\gh 9 _m cases ! body is conv]t$ into a circul> or elliptical section by ! use ( light wood =m]s fa/5$ to ! ma9 frame4 ,ano!r well kn[n type is ! ,monocoque body1 fir/ us$ on ! ,gordon-,b5nett ,dep]duss9 monoplane4 ,?is fuselage is a circul> %ell built up ( ?ree-ply tulip wood1 ?us =m+ a s+le piece body ( great /r5g?4 ,! ?ree-ply %ell is really a v5e]1 ! lay]s proce$+ spirally ar\nd ! body1 ea* lay] be+ securely glu$ to its neighbor4 ,betwe5 ea* lay] is a scrim lay] ( treat$ silk1 & ano!r fabric lay] is g5]ally glu$ to ! outside ( ! %ell4 ,! %ell is v ?91 ! total ?ickness ( ! ?ree lay]s ( wood & fabric 9 mod]n ma*9es be+ r less ?an #a4e millimet]s 7ab\t #a_/af in*74 ,9 ! orig9al ,deps ?is 0 some:at great]1 #j4ae in*4 ,monocoque con/ruction z a rule is heavy & exp5sive1 b (f]s ! great advantage ( /r5g?1 p]fect alignm5t at all times1 & ( (f]+ resi/ance to rifle & %ell fire4 ,if ! longitud9als ( a truss type are /ruck ) a bullet1 or %ell fragm5t1 ! entire fuselage is likely to fail1 b a monocoque body may be well p]=at$ be=e failure is likely to take place4 ,! ,am]ican ,l4 ,w4 ,f4 ,tractor ,biplane has a monocoque body 9 :i* spruce lam9ations are us$ in/ead ( h>dwood4 ,"o ply runs longitud9ally :ile ! o!r two lay]s are spirall$ to ! "r & left respectively4 ,betwe5 ea* lay] is a scrim lay] ( treat$ silk1 ! :ole con/ruction be+ cov]$ ) a f9al lay] ( fabric1 sev]al coats ( wat]pro( comp\nd1 & f\r f9al coats ( sp> v>ni%4 ,:5 us$ = seaplanes ! wood plies are /it*$ toge!r ) /rong wires to prev5t sep>ation due to dampness4 ,s9ce spruce is us$ 9 place ( h>dwood1 ! con/ruction is light] ?an 9 ,european models1 & ! ,l4 ,w4 ,f4 ,company claim t x is light] ?an ! usual truss con/ruction4 ,an additional advantage ( ! monocoque con/ruction is t ! pilot is protect$ aga9/ spl9t]s or p5etration by ! limbs ( trees :5 mak+ a =c$ l&+ 9 ! bru%4 ,ano!r =m ( monocoque con/ruction 0 adopt$ by ! ,fr5* build]1 ,bl]iot1 at ! beg9n+ ( ! w>4 ,! fuselage ( ?is ma*9e 0 cov]$ ) papi]-ma*e1 ! a% longitud9als be+ buri$ 9 ?is mixture4 ,! papi]-ma*e is built up ) glue & silk ?reads4 ,?is con/ruction is v light & /rong1 b is exp5sive & difficult to protect aga9/ moi/ure4 ,! front ( ! fuselage is protect$ ) a #c millimet] /eel armor plate to protect ! pilot aga9/ bullets & %rapnel4 ,! papi]-ma*e portion ( ! body is n easily spl9t]$ by bullets4 ,a ?ird =m ( monocoque1 exp]im5t$ ^u by ! au?or1 is ! /eel %ell type 9 :i* ! ?ree-ply wood v5e] is supplant$ by a ?9 /eel %ell4 ,?is out] %ell is /r5g!n$ by suitable /iff5] angles4 ,) a %ell ?ickness ( #j4jac in*1 ! /r5g? is equal to ! /r5g? ( a wood %ell & is slightly less 9 weight4 ,x has ! advantage ( be+ easily & *eaply =m$ into %ape & is absolutely pro( aga9/ ! influ5ces ( heat & moi/ure4 ,x _c spl9t]1 w n cat* fire & (f]s a maximum resi/ance aga9/ p5etration4 ,!re is yet mu* exp]im5tal "w to be done be=e ! con/ruction is p]fect$4 ,ab\t midway betwe5 ! truss fuselage & ! monocoque is ! v5e] con/ruction us$ on _m ( ! mod]n ,g]man a]oplanes4 ,9 g5]al1 ?is may be describ$ z be+ a v5e] %ell fa/5$ to ! conv5tional wood longitud9als4 ,/ay wires are n 9 g5]al use1 ! v5e] tak+ ! %e> due to ! b5d+ movem5t4 ,six long]ons are us$ in/ead ( f\r1 ! two additional memb]s be+ locat$ midway on ! v]tical sides4 ,transv]se wood frames take ! place ( ! transv]se /ay wires us$ 9 ! truss type4 ,examples ( ?is type are met ) 9 ! ,albatros de ,*asse & 9 ! ,go?a bomb dropp]4 ,! s+le seat]1 ,rol&1 has a fuselage ( circul> section1 ) a true monocoque v5e] con/ruction1 b ,g]man-l1 re9=ces ! con/ruction ) a numb] ( v small longitud9als4 ,9 ?is ma*9e !re are #f lay]s1 or plies1 ( wood re9=c$ by fabrics4 ,! entire ?ickness ( ! wood & fabric is only #a4e millimet]s 7#a_/af in*74 ,/eel tube fuselage dates back to ! beg9n+ ( ! a]oplane indu/ry4 ,9 ?is type ! wood longitud9als ( ! wood truss type are replac$ ) ?9 gage /eel tubes1 ! cross /ruts be+ also ( ?is mat]ial4 ,! diagonal brac+ may be ei!r ( /eel wire1 z 9 ! wood frames1 or may be made up ( incl9$ /eel tube memb]s t p]=m bo? ! duty ( ! /ay wires & /ruts4 ,= ! greate/ weight-effici5cy1 a /eel tube body %\ld be triangul> 9 section r ?an squ>e4 ,a triangul> section saves "o longitud9al & a multitude ( wire /ruts & connections s9ce no transv]se brac+ is necess>y4 ,connections on a /eel tube fuselage are difficult to make & are heavy4 ,!y require mu* braz+ & weld+ ) ! result t ! /r5g? is unc]ta9 & ! jo9t is heavy4 ,a v mod]n type ( /eel con/ruction is t develop$ by ! ,/urtevant ,company4 ,! memb]s ( ! ,/urtevant fuselage are 9 ! =m ( /eel angles & *annels1 simil> 9 _m respects to ! sections us$ 9 /eel build+s & bridges4 ,! jo9ts are rivet$ & p9n$ z 9 /eel /ructural "w4 ,! longitud9als are angles & ! /ruts are *annels4 ,cry/allization ( ! /eel memb]s is prev5t$ by ! use ( special p9-connect$ jo9ts provid$ ) %ock absorb+ wa%]s4 ,ow+ to ! simplicity ( ! rivet$ jo9ts1 !re is practically no weight due to connections1 & s9ce ! weight ( connections is a l>ge item 9 ! total weight ( a fuselage1 ! ,/urtevant is a v light /ructure4 ,accord+ to ,g4 ,c4 ,lo5+1 eng9e] ( ! company1 ! fitt+s ( a l>ge wood fuselage weigh at lea/ #fj p\nds4 ,?is is almo/ entirely sav$ ) ! rivet$ connections4 ,illu/ration3 ,truss ,type ,fuselage ( ,curtiss ,r-#d ,biplane1 ,%[+ ,motor & ,front ,radiator ,m\nt$ 9 ,place4 ,x ,w ,be ,not$ ,t ! ,upp] & ,l[] ,long]ons ,are ,*annel$ ,out = ,lightness & ,h5ce ,^! ,memb]s ,are ( ! ,i ,beam or ,*annel ,=m4 ,propell] ,flange ,is ,%[n ,project+ ,?r\gh ! ,radiator ,op5+4 ,a novel type ( wood fuselage has be5 describ$ by ,p\ls5 9 ,flight4 ,eight small longitud9als are us$ :i* are held 9 place by ?ree-ply wood5 =m]s or diaphragms4 ,wire brac+ is us$ 9 a longitud9al direction1 b n transv]sely 9 ! plane ( ! diaphragms4 ,! cross-section is octagonal1 & ! complet$ /ructure is cov]$ ) fabric4 ,= ! amateur ?is (f]s _m advantages s9ce ! wir+ is r$uc$ to a m9imum & all ( ! memb]s are small & easily b5t to %ape4 ,x is fully z light z any type ( body1 = ! connections are only ?9 /rips ( /eel bolt$ to ! diaphragms ) small ma*9e screws4 ,no =m]s are ne$$ = ! deck1 & ! ma*9e c be giv5 a close approximation to ! ideal /ream-l9e =m ) little tr\ble4 99,truss ,type ,fuselage994 ,we w n[ take up ! con/ruction ( ! truss type ( fuselage 9 m detail1 & inve/igate ! m]its ( ! diff]5t types ( connections us$ 9 fa/5+ ! frame toge!r4 ,l e "p ( ! a]oplane1 ! fuselage mu/ ei!r be "r or wrong1 !re is no middle c\rse4 ,fig4 #bc %[s a side elevation ( a typical truss type fuselage built up ) wood longitud9als & /ruts1 ! t5sion memb]s be+ high t5sile /r5g? /eel wire & cable4 ,l & ,l' are ! upp] & l[] longitud9als1 ,s-,s-,s are ! v]tical /ruts1 & ,t-,t-,t are ! horizontal cross /ruts :i* run across ! frame4 ,! eng9e b$ is ! timb] m>k$ ,b at ! front ( ! body4 ,! upp] w+ is atta*$ to ! body ?r\gh ! cabane /ruts ,c1 & ! *assis connections are %[n at ,d4 ,! /]n po/ ,e closes ! re> end ( ! body 9 a knife edge & acts z a support = ! rudd] & ! re> end ( ! /abiliz]4 ,f is ! seat rail :i* c>ries ! seats & supports ! control yokes4 ,all cross brac+ is ( high t5sile /r5g? /eel wire1 or ( high /r5g? aviation cable1 ^! /r&s tak+ ! t5sile /resses :ile ! wood /ruts are 9 compression4 ,9 ! =w>d portion1 d\ble /r&$ cables are g5]ally us$1 ) solid wire appli$ to ! aft] portions4 ,! longitud9als are ( a% f ! motor to ! re> ( ! pilot's seat1 :ile ! re> longitud9als are g5]ally ( spruce4 ,9 "s ma*9es1 h[ev]1 ! entire l5g? ( ! longitud9als is a%4 ,! latt] arrangem5t makes a heavi]1 b /rong] body4 ,! /ruts are usually ( spruce z ?is mat]ial is /iff] ?an a% & mu* light]4 ,illu/ration3 ,diagram ( ,typical ,truss ,type ,fuselage1 ,%[+ ,pr9cipal ,memb]s 9 ,place4 ,illu/ration3 ,fuselage ( ,hansa-,br&5burg ,fight+ ,biplane4 ,see ,page #bfh4 ,figs4 #bg-bh-bi-cj4 ,fuselage ,details4 7,truss ,type7 ,bo? ! /ruts & longitud9als are frequ5tly *annell$ out = lightness1 z %[n by ,fig4 #bg1 ! wood5 memb] be+ left rectangul> 9 section only at ! po9ts :]e ! connections are made ) ! /ruts & cables4 ,! *annell+-out process1 if correctly foll[$1 gives v /rong /iff memb]s ) a m9imum ( cross-sectional area & weight4 ,_m captur$ ,g]man ma*9es1 on ! contr>y1 h solid longitud9als ( rectangul> section1 wrapp$ ) l95 fabric4 ,?is fabric /r5g!ns ! con/ruction & at ! same "t r$uces ! *ances ( spl9t]+ ! wood5 memb]s 9 a h>d l&+4 ,! fabric is glu$ to ! wood & ! entire wrapp+ is !n giv5 sev]al coats ( a moi/ure repell+ v>ni%4 ,9 ! old] types ( fuselage1 ! longitud9als 7 (t5 ( ! lam9at$ class1 t is1 7 built up ( sev]al lay]s ( wood glu$ toge!r 9 a s+le rectangul> mass4 ,?is r$uc$ ! t5d5cy t[>d splitt+1 b 0 v unreliable because ( ! unc]ta9ty ( ! glu$ jo9ts :5 expos$ to ! effects ( heat & moi/ure4 ,lam9at$ longitud9als are n[ seldom us$1 p>ticul>ly 9 ! region ( ! motor :]e wat] & oil are c]ta9 to wreck havoc ) ! glu$ up memb]s4 ,z ! /resses rapidly dim9i% t[>d ! tail1 x is ! g5]al practice to tap] d[n ! section ( ! longitud9al t[>d ! re> & to r$uce ! section ( ! /ruts4 ,! longitud9als are g5]ally kept con/ant 9 section f ! motor to ! re> ( ! pilot's seat1 ! tap] />t+ at ! latt] po9t & cont9u+ to ! re> end4 ,= example1 if ! longitud9al section at ! motor is #a #a_/d x #a #a_/b1 ! section at ! re> w be #a x #a1 ! wid? ( ! /ruts correspond+ to ?is tap]4 ,:ile tap]+ is v desirable f ! weight /&po9t1 x makes ! fitt+ problem v difficult s9ce ea* fitt+ mu/ be ( a diff]5t dim5sion unless ! connections c be design$ s t !y are adju/able to *anges 9 ! section ( ! longitud9als4 ,9 "o ma*9e1 ! wid? & dep? ( ! longitud9als are kept con/ant1 ! v>iation 9 weight & section be+ accompli%$ by increas+ ! dep? ( ! *annell+ z ! re> is approa*$4 ,) ?is design1 ! same fitt+s c be appli$ f "o end to ! o!r4 ,illu/ration3 ,figs4 #bg-bh-bi-cj4 ,fuselage ,fram+ ,memb]s & ,details4 ,s9ce ! load+ ( ! /ruts is comp>atively light1 !y c be mu* r$uc$ 9 section by *annell+ or by *amf]+1 z %[n by ,fig4 #bh4 ,if ! wid? & ?ickness is ma9ta9$1 mu* ( ! int]ior mat]ial c be remov$ )\t dang] ( r$uc+ ! /r5g?4 ,sket* 7,a7 9 ,fig4 #bh %[s a v common me?od ( /rut r$uction1 ! /rut be+ ( rectangul> section ?r\gh\t its l5g?1 b tap]$ 9 su* a way t x is ?icke/ at ! c5t] 7d7 & ?9ne/ at ! two ends 7e74 ,to obta9 ! correct relation betwe5 ! c5t] end ?ickness requires v c>eful calculation4 ,z %[n1 ! /rut is atta*$ to ! upp] & l[] longitud9als by %eet /eel fitt+s or sockets4 ,sket* 7,b7 %[s a simple me?od1 ! rectangul> /rut be+ *amf]$ (f at ea* ( ! f\r corn]s1 & left full size at ei!r end :]e ! fitt+s connect x ) ! longitud9als4 ,?is =m is n correct f a te*nical /&po9t1 b is g5]ally good en\gh = lightly load$ /ruts1 & has ! advantage ( be+ *eaply & easily con/ruct$4 ,9 sket* 7,c7 a *annell$ /rut is %[n1 ! c5t] portion be+ *annell$ out 9 a mann] simil> to ! *annell+ ( ! longitud9als4 ,?is light5+ process is mo/ commonly adopt$ ) ! l>ge heavily load$ /ruts 9 ! front portion ( ! fuselage1 & at ! po9ts :]e ! motor b$ is susp5d$ or :]e ! w+s & *assis are atta*$ to ! body4 ,! black dots at ! ends ( ! /ruts indicate ! bolt holes = ! fitt+s1 x be+ p]missible to drill holes 9 ! ends ( ! /ruts b n 9 ! longitud9al memb]s4 ,if ! /rut is l>ge en\gh to resi/ ! b5d+ /resses at ! c5t] x w g5]ally all[ ( holes be+ drill$ ne> ! ends )\t dang] ( /r5g? r$uction4 ,aga91 ! /ruts are always 9 compression & h5ce ! bolts may be dep5d$ ^u to p>tly take ! place ( ! remov$ mat]ial 9 c>ry+ ! compressive /resses4 ,holes %\ld nev] be drill$ 9 ! longitud9als s9ce ^! memb]s may be ei!r 9 t5sion or compression1 dep5d+ ^u ! angle at :i* ! elevator flaps are set4 ,! hole n only de/roys ! /r5g? at ! po9t at :i* x is drill$1 b ?is r$uction also ext5ds to a consid]able di/ance on ei!r side ( ! hole1 ow+ to ! fibr\s nature ( ! wood4 ,9 /eel memb]s ! effect ( ! hole is purely local & does n usually ext5d mu* beyond ! edge ( ! hole4 ,consid]+ ! wood beam z consi/+ ( a s]ies ( p>allel fib]s1 x w be se5 t sev]+ any "o ( ! fib]s w decrease ! /r5g? ( ! wood ?r\gh a di/ance equal to ! l5g? ( ! cut fib]1 or at lea/ ?r\gh a di/ance equal to ! natural %e> value ( ! res9s t b9d ! fib]s toge!r4 ,fuselage fitt+s are almo/ numb]less 9 ! v>iety ( design4 ,!y mu/ be v light & /rong1 mu/ be appli$ )\t drill+ ! long]ons1 & %\ld be simple & *eap to con/ruct4 ,!y are usually made ( %eet /eel ( f #j4bj to #j4cj po9t c>bon1 & may be ei!r b5t or press$ into %ape4 ,at ! po9ts :]e ! /ruts are jo9$ to ! longitud9als1 ! fitt+s connect /ruts & wires 9 ?ree planes1 ! v]tical /ruts & =e & aft wires2 ! transv]se wires & horizontal /ruts1 & ! top & bottom wires t lie 9 a horizontal plane4 ,!re are at lea/ #f connections at e /rut1 f\r ( ! connections be+ made to ! /ay wires or cables4 ,a simple connection is !re=e v h>d to design4 ,fig4 #bi %[s a typical fuselage panel & ! int]connect$ memb]s 9 _! usual relation4 ,,lu & ,,ll are ! top & bottom longitud9als at ! "r1 :ile ,,lu' & ,,ll' are ! longitud9als at ! "r h& side4 ,! v]tical /ruts ,,sv & ,,sv' sep>ate ! top & bottom longitud9als1 :ile ! horizontal /ruts ,,% & ,,%' sep>ate ! "r & left h& sides ( ! fuselage body4 ,! wires w-w-w-w brace ! body =e & aft 9 a v]tical plane4 ,! wires t-t lie 9 a horizontal plane1 produce compression 9 ! horizontal /ruts ,,%-,,%'1 & /iff5 ! frame aga9/ side ?ru/4 ,! transv]se rectangle ,,sv-,,%-,,sv'-,,%' is held 9 %ape by ! transv]se /ay wires ,w-,w1 ?is rectangle1 & ! /ays resi/+ torsional /ress 7twi/+71 act aga9/ ! /ruts compos+ ! sides ( ! rectangle4 ,9 "s ,european ma*9es1 ! wires ,,ww are elim9at$1 & are replac$ by ?9 v5e] panels1 or %ort wood knee braces z %[n by ,fig4 #cj4 ,! section %[s ! longitud9als ,l-,l-,l-,l & ! /ruts ,,sv-,,sv'-,,%-,,%' brac$ by ! v5e] %eet or diaphragm ,d4 ,?is diaphragm is well p]=at$ by light5+ holes & effectually resi/s any torsional /ress t may be due to motor torque1 etc4 ,s9ce ! transv]se wires ,w-,w 9 ,fig4 #bi are r inaccessible & difficult to adju/1 ! v5e] diaphragm 9 ,fig4 #bg has a great advantage4 ,9 ?is reg>d x may be /at$ t wire brac+ is n a desirable con/ruction1 & ! sub/itution ( solid v5e] is a /ep 9 advance4 ,wire brac+ has always seem$ l a make%ift to ! au?or4 ,! compression & t5sion memb]s be+ ( mat]ials ( widely diff]5t *>act]i/ics are n suitable 9 positions :]e a /rict alignm5t mu/ be ma9ta9$ "u diff]5t conditions ( temp]ature & moi/ure4 ,! diff]5ce 9 expansion betwe5 wire & ! wood compression memb]s produces alt]nate tightness & slackness at ! jo9ts1 & z ?is is n a uni=m v>iation at ! diff]5t jo9ts1 ! frame is always weav+ 9 & out ( l9e4 ,"u ! influ5ce ( moi/ure ! wood ei!r swells or contracts1 :ile ! wire & cable ma9ta9 _! orig9al l5g?s & adju/m5ts4 ,! result is t a frame ( ?is k9d mu/ be giv5 con/ant att5tion if correct alignm5t is desir$4 ,! adju/m5t ( a wire brac$ wood fuselage %\ld be p]=m$ only by a skill$ me*anic1 z x is easily possible to /ra9 ! memb]s beyond ! ela/ic limit by c>eless or ignorant h&l+ ( ! wire /ra9+ turnbuckles4 ,9 ! endeavor to br+ an old w>p$ fuselage back into l9e x is c]ta9 t ! initial t5sion 9 ! wires c be made great] ?an ! maximum work+ /ress = :i* ! wires 7 orig9ally int5d$4 ,%r9kage ( ! wood also loos5s ! bond betwe5 ! wood5 memb]s & ! /eel fitt+s unless ?is is cont9ually be+ tak5 up4 ,"s =m ( unit con/ruction1 su* z ! monocoque body1 is f> m desirable ?an ! common =m ( wire truss$ wood body4 ,illu/ration3 ,fuselage ,details ( ,de ,havill& ,v4 ,s+le ,seat ,*as]4 ,a ,rot>y ,le ,rhone ,motor ,is ,us$ 9 a ,circul> ,c[l4 ,! ,diagonal ,brac+ 9 ! ,front ,section is ,re9=c$ by ,lam9at$ ,wood ,plates ,in/ead ( by ,wires4 ,dim5sions 9 ,millimet]s4 99,fuselage ,fitt+s994 ,9 ! e>ly days ( aviation ! fuselage fitt+s on _m ma*9es 7 made ( alum9um alloy4 ,?is metal1 :ile light1 0 unc]ta9 9 reg>d to /r5g?1 h5ce ! use ( ! alloy 0 gradually ab&on$4 ,at pres5t ! great] "p ( ! fitt+s are /amp$ /eel1 =m$ out ( ! %eet1 & are ( a uni=m /r5g? = simil> designs & classes ( mat]ial4 ,! /eel be/ adapt$ = ! fitt+s has a c>bon cont5t ( f #j4bj to #j4cj1 ) an ultimate /r5g? ( #fj1jjj p\nds p] squ>e in*1 & a #ae p] c5t elongation4 ,! /eel z receiv$ f ! mill %\ld be anneal$ be=e /amp+ or =m+ to avoid fracture4 ,aft] ! =m+ x c be giv5 a /r5g!n+ heat treatm5t4 ,a l[] /eel ly+ betwe5 #j4aj & #j4ae c>bon is s(t] & c be =m$ )\t anneal+ be=e ! =m+ process4 ,?is mat]ial is v weak1 h[ev]1 ! t5sile /r5g? be+ ab\t #dj1jjj p\nds p] squ>e in*4 ,fitt+s made ( ! #j4ae c>bon /eel w !re=e be heavi] ?an ) ! #j4cj c>bon /eel = ! same /r5g?4 ,! ?ickness ( ! metal w v>y f #a_/cb to #a_/af1 dep5d+ ^u ! load com+ on ! fitt+4 ,a typical fuselage /rut fitt+ is %[n by ,fig4 #ca-;,a 9 :i* ,l-,l-,l are ! long]ons1 d is ! fitt+ /rap pass+ ov] ! long]ons1 ,s & ,s are ! v]tical & horizontal /ruts respectively4 ,! /ay wires are fa/5$ to e>s 7b7 b5t out ( ! fitt+1 ! wires be+ atta*$ ?r\gh ! adju/able turnbuckles 7t74 ,! /ruts are provid$ ) ! %eet /eel f]rules m>k$ 7,f74 ,!re are no bolts pass+ ?r\gh ! longitud9als ,l-,l'1 ! fitt+ be+ clamp$ to ! wood5 memb]4 ,?is is v simple & light fitt+4 ,fig4 #ca-;,b is a simil> type1 s simple t fur!r discussion is unnecess>y4 ,fig4 #cb %[s a fuselage /rut fitt+ z us$ on ! ,/&>d ,type ,h-#c ,biplane4 ,we are indebt$ to ,a]ial ,age = ?is illu/ration4 ,?is consi/s ( a %eet metal /rap ( ,u =m :i* is b5t ov] ! longitud9al & is bolt$ to ! v]tical /rut4 ,at ei!r side ( ! /rut are ?r\gh bolts to :i* b5t /raps atta* ! turnbuckles4 ,^! /raps are loop$ ar\nd ! bolts & =m a clevis = ! male ends ( ! turnbuckles4 ,illu/ration3 ,fig4 #ca4 ,typical ,fuselage ,/rut ,fitt+s4 ,an old =m ( fuselage connection us$ on ! ,nieuport monoplane is %[n by ,fig4 #cc1 an example ( a type 9 :i* ! bolts are pass$ ?r\gh ! long]on memb]4 ,?is fitt+ is v light b objectionable because ( ! pi]c+ ( ! long]on4 ,an ,au/rian a]oplane1 ! ,hansa-,br&5b]g1 has a wood fuselage 9 :i* no /ay wires are us$4 ,?is fuselage is %[n by ,fig4 #bc;a4 ,bo? ! v]tical & incl9$ memb]s are wood /ruts4 ,! out] cov]+ ( wood v5e] makes ! use ( /ay wires unnecess>y s9ce ! %ea? takes up all horizontal /resses1 & h5ce =ms a sort ( plate gird] con/ruction4 ,! ,g]man ,albatros also employs a wireless v5e] fuselage1 ! con/ruction be+ %[n 9 detail by ,figs4 #cf & #cf;a4 ,?ree long]ons are locat$ on ei!r side ( ! body1 ! ?ird memb] be+ plac$ at ab\t ! c5t] ( ! v]tical side4 ,z w be se51 ! v5e] makes ! use ( wire brac+ & metal connections unnecess>y4 ,! v5e] also insures p]fect alignm5t4 ,illu/ration3 ,fig4 #cb4 ,fuselage ,/rut ,fitt+s ( ! ,/&>d ,h-#c ,tra9+ ,biplane4 99,w+ ,connections994 ,! l[] w+s are atta*$ to ! l[] longitud9als by a special %eet /eel fitt+ :i* also g5]ally connects to a v]tical /rut at ?is po9t1 & to an extra heavy horizontal /rut4 ,a %eet metal clevis1 or socket1 on ! w+ sp> is p9n$ to ! fuselage half ( ! fitt+ s t ! w+ c be easily deta*$ :5 ! ma*9e is to be dissembl$4 ,at ?is po9t a connection is also provid$ = ! end ( ! inn] int]plane /ay wires4 ,! horizontal /rut at ! po9t ( w+ atta*m5t is really a cont9uation ( ! w+ sp> & takes up ! ?ru/ due to ! incl9ation ( ! int]plane /ays4 ,9 ! majority ( cases ! horizontal ?ru/ /rut is a /eel tube1 ) ! h+$ connection braz$ to its out] ends4 ,?is is "o ( ! mo/ important & heavily load$ connections on ! ma*9e & %\ld be design$ accord+ly4 ,illu/ration3 ,fig4 #cc4 ,fuselage ,fitt+s ( ! ,nieuport ,monoplane4 ,fig4 #cg %[s a typical w+ to fuselage connection ( ! h+e type4 ,! w+ sp> 7,g7 is cov]$ ) a %eet /eel f]rule 7,a7 at its inn] end4 ,two eye b>s 7,b7 are bolt$ to ! w+ sp>1 & ov] ! f]rule1 ! eyes ( ! b> project+ beyond ! end ( ! sp>4 ,?is =ms ! w+ half ( ! connect+ h+e4 ,! eyes are fa/5$ to ! fuselage h+e memb] 7,h7 by means ( ! p9 7,e74 ,?is p9 has a tap]$ end = easy entry into ! jo9t1 & is pi]c$ ) holes at ! out] end = cott] p9s or a simil> reta9+ device4 ,! fuselage h+e memb] 7,h7 is braz$ to ! end ( ! /eel tube /rut 7,t74 ,?is tube runs across ! fuselage f w+ sp> end to w+ sp> end4 ,/rut tube 7,t7 lies on1 & is fa/5$ to1 ! fuselage long]on 7,l71 & also lies betwe5 ! two halves ( ! v]tical /rut 7,s74 ,! v]tical /rut is cut out at its l[] end = ! receipt ( ! /eel tube 7,t74 ,a /eel plate is braz$ to ! tube1 is wrapp$ ab\t ! long]on 7,l7 & is bolt$ to ! v]tical /rut 7,s74 ,! int]plane /ay 7,f7 is atta*$ to ! p9 7,e7 at ! po9t ( juncture ( ! w+ sp> eye & ! fuselage memb] ( ! h+e4 ,a coll> 7,i7 is braz$ to ! tube1 & =ms a means ( atta*+ ! fuselage /ays 7,d74 ,! drift wires 7,c7 ( ! w+s are atta*$ to an eye at ! end ( "o ( ! w+ sp> bolts4 ,z %[n1 ! fitt+ 7,h7 is a /eel =g+1 v c>efully ma*9$ & r$uc$ 9 weight4 ,! inside w+ ribs are indicat$ by 7,k71 f :i* x w be se5 t !re is a gap betwe5 ! end ( ! w+s & ! outside face ( ! fuselage4 ,illu/ration3 ,fig4 #cf4 ,v5e] ,fuselage ,con/ruction ( ! ,g]man ,albatros ,spe$ ,sc\t4 ,body ,outl9e ,is ,obta9$ by ,v5e] ,diaphragms & no ,/ay ,wires ,are ,us$4 ,fig4 #cf-;a %[s ! con/ruction ( ! w+ jo9t ( ! ,g]man ,albatros ma*9e4 ,! fuselage is ( monocoque con/ruction :i* all[s ( a simple atta*m5t to ! out] %ell4 ,?is is a v /urdy & simple connection4 ,fig4 #ch-,z is ! w+ atta*m5t detail ( ! ,engli% ,london & ,prov9cial ,biplane 7#aiaf71 ! fuselage 9 ?is case be+ ( ! wire truss$ wood type4 ,we are indebt$ to ,flight = ?is illu/ration4 ,illu/ration3 ,fig4 #cf-;a4 ,details ( ,albatros ,v5e] ,fuselage ,con/ruction4 ,9 "s ma*9es ! int]plane /ay wires are atta*$ to a lug =m$ f ! atta*m5t plate1 b we d n consid] t ?is con/ruction is z good z ! type 9 :i* ! wire is atta*$ directly to ! w+ sp> p94 ,:ile ! =m] may be easi] to assemble1 ! atta*m5t ( ! wire to ! p9 elim9ates any ecc5tricity1 or b5d+ mom5t1 due to ! pull ( ! int]plane /ay4 ,! atta*m5t 9 ! ,l4 ,w4 ,f4 insures aga9/ any ecc5tricity 9 ! /ay atta*m5t1 & at ! same "t makes ! assembly & dism\nt+ a v simple matt]4 ,illu/ration3 ,fig4 #cg4 ,w+ ,connection to ,fuselage4 99,*assis ,memb] ,atta*m5t994 ,! atta*m5t ( ! *assis /ruts g5]ally involves "s difficulty z ^! memb]s usually int]sect ! l9e ( ! long]ons at a v awkw>d angle4 ,if ! w+ atta*m5t is ne> ! same po9t1 z x g5]ally is1 ! detail is made d\bly difficult4 ,! *assis mu/ be p9 connect$ z 9 ! case ( ! w+ jo9t s t ! *assis memb]s c be easily & quickly remov$4 ,a detail ( a *assis to body connection is %[n by ,fig4 #ci4 ,9 ?is figure 7,l7 is ! l[] long]on1 7,s7 is ! v]tical fuselage /rut1 & 7,c7 is "o ( ! *assis memb]s4 ,! upp] end ( ! *assis memb] is envelop$ 9 a %eet /eel f]rule 7,d7 :i* is bolt$ 9 place1 & :i* is provid$ ) a clevis at its upp] end = ! atta*m5t p9 7,p74 ,a plate 7,e7 is bolt$ to ! fuselage /rut 7,s7 & is pass$ ar\nd ! l[] long]on 7,l71 a h+e jo9t 7,h7 be+ provid$ = atta*m5t to ! *assis f]rule ?r\gh ! p9 7,p74 ,e>s or lugs are left at 7,g-,g7 = ! atta*m5t ( ! fuselage /ays 7,b-,b74 ,on ! inn] side ( ! plate 7,e7 are atta*m5t lugs = ! horizontal /rut 7,h74 ,x w be not$ t ! plate 7,e7 is well provid$ ) light5+ holes s t ! weight c be kept d[n to a m9imum4 ,! p9 is tap]$ at ! end1 & is provid$ ) cott] p9 holes4 ,! fitt+ 9 g5]al is small1 & does n produce any great degree ( head resi/ance1 ! small "p expos$ be+ ( good /reaml9e =m4 ,illu/ration3 ,fig4 #chx4 ,w+ ,connection ( ! ,albatros ,reconnaissance ,biplane4 ,fig4 #chy4 ,w+ ,atta*m5t ( ,albatros ,fight] ) ,p9 ,jo9t4 ,fig4 #chz4 ,w+ ,connection ( ,london & ,prov9cial ,biplane4 ,great c>e %\ld be tak5 9 braz+ or weld+ ^! fitt+s1 s9ce ! heat *anges ! /ructure ( ! metal & greatly r$uces its /r5g?4 ,! braz+ temp]ature v>ies f #a1ejj to #a1gjj degrees1 a po9t well above ! temp]+ heat ( /eel4 ,attempts h be5 made to heat treat ! metal aft] ! braz+ op]ation1 b ) v little success1 ow+ to ! fact t ! heat treat+ temp]ature is g5]ally at or above ! melt+ po9t ( ! braz+ spelt]1 h5ce is likely to cause holes & op5+s 9 ! braz$ jo9ts4 ,) acetyl5e weld$ jo9ts ! p>ts c1 & %\ld be1 heat treat$ aft] ! weld+4 ,:ile ?is is an app>5t advantage ( acetyl5e weld+1 all p>ts _c be successfully h&l$ 9 ?is mann]4 ,! weld+ tor* c only jo9 edges1 :ile ! braz+ spelt] c be appli$ ov] almo/ any area ( surface4 ,weld+ is v successful 9 jo9+ ?9 /eel tubes :ile 9 _m fitt+s made ( %eet metal1 braz+ is ! only feasible op]ation4 ,illu/ration3 ,fig4 #ci4 ,*assis ,connection4 ,bo? me?ods h a common fault1 9 t !y are unreliable4 ,imp]fect welds & braz+ are n always app>5t f ! outside1 actual breakage ( ! "p be+ necess>y to det]m9e ! true nature ( ! jo9t4 ,,fuselage ,,weights4 99,di/ribution ( ,weight994 ,! weight ( a fuselage dep5ds ^u ! span ( ! w+s1 ^u ! seat+ capacity1 & ^u ! weight & type ( ! p[] plant4 ,! weight also v>ies consid]ably ) ! type ( con/ruction1 t is1 :e!r ( truss1 v5e]1 or monocoque con/ruction4 ,a heavily p[]$ ma*9e1 or "o c>ry+ m ?an a s+le p]son1 requires heavi] /ructural memb]s & h5ce weighs m ?an a small s+le seat]4 ,! am\nt ( fuel c>ri$ also has a consid]able be>+ on ! fuselage weight4 ,probably ! be/ me?od ( treat+ ?is subject is to give ! fuselage weights ( sev]al types ( well kn[n ma*9es4 ,! read] w !n h at lea/ a comp>ative basis = det]m9+ ! approximate weight4 7,truss type only47 ,!re are s _m v>iables t ! weight _c be det]m9$ by any set rule or =mula4 ,alex&] ,klem9 9 8 ,c\rse 9 ,a]odynamics & ,airplane ,design says t ! approximate weight ( a b>e wood truss type fuselage is ab\t #aej p\nds = a ma*9e hav+ a total weight ( #b1ejj p\nds4 ,= small biplane & monoplane sc\ts weigh+ approximately #a1bjj p\nds total1 ! b>e fuselage frame w weigh ab\t #gj p\nds4 ,^! figures are = ! b>e frame alone & )\t seats1 controls1 tail skids or o!r fitt+s4 ,! weights giv5 "u ! column head$ ,wt4 ,b>e include ! eng9e b$s1 tail skids1 floor+1 c[l+ & body cov]+1 & h5ce exce$ ! bone b>e e/imate ( ,klem9 by a consid]able am\nt4 ,! all-/eel fuselage ( ! l>ge ,/urtevant battle-plane 7,model ,a7 weighs #afe p\nds inclusive ( ! /eel eng9e b$4 ,a wood51 wire brac$ fuselage ( ! same size & /r5g? weighs well ov] #bjj p\nds1 ! metal fitt+s & wires weigh+ ab\t #fj p\nds alone4 ,a% is us$ 9 ! wood example = ! long]ons4 ,! /ruts & diagonal memb]s 9 ! ,/urtevant metal fuselage are rivet$ directly to ! longitud9als1 )\t fitt+s or connection plates4 ,! safety factor = air loads is #h1 & = ! gr\nd loads due to taxi-+ ov] ! gr\nd1 a safety factor ( #d is us$4 ,aft] a m9ute comp>ison ( ! items compris+ ! fuselage ( ! ,curtiss ,,jn#d-;,b & ! ,/&>d ,h-#c1 ,klem9 f9ds t ! fuselage assembly ( ! ,/&>d ,h-#c am\nts to #ac4f p] c5t ( ! total load$ weight1 & t ! fuselage ( ! ,curtiss ,,jn#d-;,b is #ae4e p] c5t ( ! total4 ,tanks1 pip+ & controls are omitt$ 9 bo? cases4 ,= ma*9es weigh+ ab\t #b1ejj p\nds1 ,dr4 ,j4 ,c4 ,hunsak] f9ds ! body weight av]ag+ #h4b p] c5t ( ! total1 ?is figure be+ ! av]age tak5 f a numb] ( ma*9es4 ,on c>eful exam9ation x w be f\nd t ! fuselage assembly 7b>e7 am\nts to a trifle less ?an ! w+ gr\p = biplanes hav+ a total weight ( f #a1ijj to #b1ejj p\nds4 ,! relation betwe5 ! w+ weight & ! fuselage weight seems to be> a clos] relation ?an betwe5 ! fuselage & total weights4 ,we w set ^! diff]5t relations =? 9 ! foll[+ table3 ,,p]c5tage ,,( ,,fuselage ,,weight ,fuselage ,weight z ,p]c5tage ( ! ,total ,load ,"n ( ,w+ ,weight ,z ,plane or ,body ,body ,body ,p]c5tage ( ,total ,inve/igator ,assembly ,assembly ,assembly ,weight ,b>e & & ,equipm5t ,p[] ,plant ,curtiss #ae4ej #ag4hf #dc4if #ad4ae ,,jn#d-;,b ,/&>d ,h-#c #ac4fj #ag4gj #de4dj #ad4eb ,j4,c4 #h4bj #aa4ej #cd4cj #af4ej ,hunsak] ,au?or's #ad4if #ag4fb #df4ff #ad4fj ,exp]i5ce ,av]age ( #ac4jf #af4ag #db4eh #ad4id ,above ,9 ! above table1 ! column head$ ,body ,assembly & ,equipm5t includes ! body frame1 controls1 tanks & pip+4 ,9 ! f\r? column1 ! radiator1 motor1 propell]1 wat]1 & exhau/ pipe h be5 add$4 ,= ! av]age value x w be se5 t ! b>e fuselage is ab\t #a4hh p] c5t l[] ?an ! weight ( ! w+s4 ,x %\ld be not$ t ! w+ weight giv5 is ! weight ( ! surfaces alone1 & does n include ! weight ( ! int]plane /ruts1 wires & fitt+s4 ,! weight ( ! w+ surfaces z above w av]age ab\t #j4ge p\nds p] squ>e foot4 ,bas$ on ! above figures1 we c obta9 a r\gh rule = obta9+ ! approximate weight ( ! fuselage1 at lea/ accurate en\gh = a prelim9>y e/imate4 ,if ,a ! total area ( ! w+s1 !n ! total weight ( ! w+s w be express$ by w #j4ge;,a4 ,! weight 7f7 ( ! fuselage c be %[n z f #ac4jf_/adid x w #j4fe;,a4 99,example994 ,! area ( ! ,/&>d ,h-#d is #edb squ>e feet total4 ,f9d ! approximate weight ( ! fuselage4 ,by ! =mula1 f #j4fe;,a #j4fe x #edb #ceb p\nds4 ,! actual b>e weight is #cjb4j p\nds4 ,= sev]al o!r ma*9es1 ! actual weight is great] ?an ! weight calculat$ by ! =mula1 s t ! rule c be tak5 z a fair av]age1 especially = a new type t is n z ref9$ 9 detail z ! ,h-#c4 ,,size ,,( ,,long]ons ,! size ( ! long]ons1 t is1 ! section1 is influ5c$ by _m factors4 ,z ^! memb]s mu/ resi/ fly+ loads1 ! lev]age ( elevator flaps1 /resses due to control wires1 l&+ /resses & ! weight ( ! motor & p]sonnel x is always advisable to itemize ! load+ & !n prep>e a diagram to obta9 ! /resses 9 ! diff]5t memb]s4 ,?is latt] me?od is a me?od = a tra9$ eng9e]1 b an exhau/ive description ( ! me?od ( proc$ure w be f\nd 9 books on ! subject ( ,/r5g? ( ,mat]ials4 ,= ! practical man1 ,i give ! foll[+ li/ ( long]on dim5sions s t he w h at lea/ a guide 9 ! selection ( 8 mat]ial4 ,! l5g? ( ! fuselage & p[] ( motor are giv5 s t ! read] c obta9 sizes by comp>ison1 al?\gh ?is is a crude & inaccurate me?od4 ,z ! long]ons tap] f front to back1 ! sizes ( ! section are giv5 at ! motor end1 & also at ! tail4 ,! size ( ! front memb]s dep5ds pr9cipally ^u ! weight ( ! motor & ! pass5g] load1 :ile ! re> long]ons c>ry ! elevator loads & ! tail skid %ock4 ,if ! rudd] is high above ! fuselage x introduces a twi/+ movem5t t may be ( consid]able importance4 ,! loads on ! /abiliz]1 elevators & ! v]tical rudd] are v sev]e :5 /raight5+ out aft] a /eep dive or 9 loop+1 & ! pull on ! control wires ex]t$ by ! aviator at ?is "t greatly adds to ! total /ress4 ,9 ! front ( ! fuselage1 ! motor ex]ts a /eady torque 7twi/7 9 addition to ! /ress due to its weight1 & to ?is mu/ be add$ ! gyroscopic =ce caus$ by ! propell] :5 ! ma*9e is sudd5ly *ang$ 9 ! direction ( flight4 ,! comb9ation ( ^! =ces act+ at diff]5t times makes ! calculation v difficult4 ,9 ! case ( ! ,curtiss ,r-#d1 ! front long]ons tap] d[n f ! motor #a4fc x #a4be to a po9t directly beh9d ! pilot's seat1 ! section at ! latt] po9t be+ #a4be x #a4be4 ,f ?is po9t ! re> long]ons tap] d[n to #a x #a at ! tail4 ,at ! motor1 ! section is #a4fc x #a4be4 ,! longitud9als ( ! ,bl]iot monoplane are lam9at$ & are built up ( alt]nate lay]s ( spruce & a%4 ,?is is an old type ( ma*9e & ?is practice has s9ce be5 discont9u$4 ,x w be not$ t z ! p[] is increas$1 ! size ( ! front long]ons is g5]ally increas$1 al?\gh ?is is n always ! case 9 spe$ ma*9es4 ,! ,*icago ,a]o ,works' ,/> fuselage c\ld easily c>ry a #ij horsep[] motor1 al?\gh ?is size is n regul>ly in/all$4 99,pu%] ,type ,fuselage 7,nacelle7994 ,comp>$ ) ! tractor biplane & ! monoplane fuselage1 ! body ( ! pu%] is v %ort & light4 ,! latt] body simply acts z a support = ! motor & p]sonnel s9ce ! tail loads are c>ri$ by ! outrigg]s or tail booms4 ,! motor is locat$ at ! re> end ( ! body & may be ei!r ( ! air or wat]-cool$ type4 ,! accompany+ figure %[s a typical pu%] type body1 or ,nacelle z x is sometimes call$4 ,! advantages ( ! pu%] type = milit>y s]vice are obvi\s4 ,! obs]v] or gunn] c be plac$ imm$iately 9 ! front :]e 8 vision is unob/ruct$1 & :]e ! angle ( fire is at a maximum4 ,illu/ration3 ,typical ,pu%] ,body ,%[+ ,w+s1 & ,outrigg] to ,tail ,surfaces4 99,tw9 ,motor$ ,fuselage994 ,tw9 motor$ a]oplanes g5]ally h ! p[] plants m\nt$ at a po9t ab\t midway betwe5 ! fuselage & tips ( ! w+s4 ,9 almo/ e case1 ! p[] plants are ( unit con/ruction1 t is to say1 consi/ ( ! motor1 radiator & propell] complete on "o support1 only ! fuel & oil tanks be+ m\nt$ 9 ! fuselage4 ,! fuselage ( ! tw9 may be simil> 9 l5g? & g5]al con/ruction to t ( ! tractor biplane1 or x may be a %ort nacelle simil> to t us$ 9 ! pu%] type4 ,9 any case1 ! obs]v] c be locat$ 9 ! extreme front ( ! body4 ,an int]e/+ & unusual con/ruction is ! body ( ! ,caproni ,biplane 7#aiaf74 ,a c5t] nacelle c>ries ! pass5g]s1 a pu%] screw be+ locat$ at ! re> ( ! c5tral body z 9 ! case ( ! pu%] biplane4 ,on ei!r side ( ! c5t] are ! motors driv+ ! tractor screws1 ea* motor be+ encas$ 9 a long tractor type fuselage t also supports ! tail surfaces4 ,! latt] fuselage s]ves to /reaml9e ! motors & takes ! place ( ! usual outrigg] con/ruction4 ,!re are ?ree bodies1 two tractor screws1 & "o pu%] screw4 ,some:at simil> 9 design is ! fam\s ,g]man ,billy ,two-,tails1 ?is ma*9e be+ equipp$ ) two tractor type bodies4 ,a motor is locat$ 9 ! front ( ea* body4 ,ea* fuselage is provid$ ) accommodations = pass5g]s1 & is long en\gh to support ! tail surfaces4 ,! ,caproni & ! ,g]man ma*9e are bo? v l>ge ma*9e & heavily p[]$4 99,u4,s4,a4 ,sea-,plane ,specifications 7#aiaf7994 ,^! gov]nm5t specifications cov] a tw9 motor$ sea-plane ) a c5tral nacelle4 ,! body is arrang$ s t ! =w>d man 7obs]v]7 c op]ate ! =w>d ma*9e gun ?r\gh a horizontal arc ( at lea/ #aej1 & ?r\gh a v]tical arc ( at lea/ #bgj1 ) ! gun at an angle ( ab\t #ge ) ! c5t] l9e ( ! body4 ,! muzzle mu/ be =w>d ( ! propell] plane4 ,! re> man 7pilot7 op]ates a ma*9e gun ?r\gh a v]tical arc ( at lea/ #aej to ! re>1 & ?r\gh a v]tical arc ( at lea/ #ahj1 ) ! gun at an angle ( ab\t #aje ) ! fuselage c5t] l9e4 ,! muzzle mu/ be to ! re> ( ! plane ( propell] rotation4 ,! numb] ( /ays & o!r important connections :i* ext5d across ! plane ( propell] rotation %all be r$uc$ to a m9imum4 ,x is consid]$ advisable to incorporate 9 ! design ( ! body su* a /ructure 79 ! plane & #h in*es =w>d ( propell] plane7 z w prev5t a brok5 propell] blade f sev]+ ! ma9 body4 ,! sy/em us$ 9 ! con/ruction ( ! cage ma/s us$ on battle%ips is sugge/$1 ) a numb] ( spruce compression memb]s 9 place ( /ay-wires4 ,! cle>ance ( ! propell] tips f ! sides ( ! c5tral body %all be f #e to #ab in*es4 ,no "p ( ! gas tanks %all lie 9 ! plane ( propell] rotation1 nor )9 a space #f in*es ahead ( ?is plane4 ,a space ext5d+ at lea/ #i in*es back f ! re> ( ! obs]v]'s seat1 & entirely across ! body1 mu/ be left op5 & unoccupi$ 9 ord] t any desir$ in/rum5ts c be in/all$ !re94 ,9 ! c5t] l9e ( ! body1 a circul> hole #i in*es 9 diamet] %all be cut 9 ! floor ( ! obs]v]'s cock-pit1 ! re> ( ! hole be+ #e in*es =w>d ( ! =w>d edge ( ! obs]v]'s seat4 ,! floor+ ( ! pilot's & obs]v]'s cockpits %all consi/ ( spruce /rips #a_/b x #a_/b spac$ at #a_/b int]vals along ! long]ons4 ,no floor+ is to be plac$ "u ! seats4 ,! safety factor ( ! body & tail /ructure %all n be less ?an #b4e1 ! air spe$ be+ tak5 at #ajj miles p] h\r ) ! elevator at an angle ( #bj & ! fix$ /abiliz] surface at #f4 ,all wire t5sion memb]s n readily accessible = inspection & adju/m5t are to be s+le /r& high t5sile /eel wire4 ,all t5sion /ays t are easily accessible %all be ( non-flexible /r&$ /eel cable4 ,= turnbuckle safety+ ,no4 #bj semi-h>d copp] wire %all be us$4 ,all cable %all be well /ret*$ be=e mak+ up ! connections4 ,a load equal to #bj or #cj p] c5t ( ! break+ load %all be appli$ = a p]iod ( f two to ?ree h\rs4 ,! h>d wire mu/ und]go a b5d+ te/ by b5d+ at a "r angle turn ov] a radius equal to ! diamet] ( ! wire1 back & =? f\r times ea* way4 ,no m ?an f\r sizes ( turnbuckles %all be us$ on ! entire a]oplane /ructure4 ,! /r5g?s & size numb]s ( ! turnbuckles w be z foll[s3 ,no4 #a #h1jjj lbs4 ,no4 #b #d1fjj lbs4 ,no4 #c #b1ajj lbs4 ,no4 #d #a1ajj lbs4 ,controls & fitt+s 9 ! vic9ity ( ! compasses %all1 z mu* z possible1 be ( non-magnetic mat]ial4 ,all /eel plate & =g$ fitt+s %all be protect$ aga9/ ! action ( salt wat] by bak+ enamel1 ! be/ /&>d ?ree coat process be+ us$4 ,all cov]$ wir+ & turnbuckles %all be coat$ by at lea/ two coats ( ,flexible ,comp\nd4 ,all /eel tub+ %all be ?or\ghly clean$1 slu%$ ) m9]al oil inside1 & plugg$ at bo? ends by wood plugs impregnat$ ) m9]al oil or p>aff9e4 ,all /eel nuts1 bolts1 p9s & cott] p9s %all be protect$ by heavy nickel plat+ ov] copp]4 ,all wood memb]s1 especially fay+ surfaces1 end gra9 butts1 sc>fs & jo9ts1 %all be protect$ aga9/ ! access ( moi/ure be=e f9al assembly by ! be/ grade ( v>ni%1 or by impregnation by p>aff9e4 ,all wood %all be /raight gra9$1 well season$1 ( uni=m weight1 & free ( knots1 pit* pockets1 *ecks or cracks4 ,spruce to be ( ! v highe/ grade ( select$ /raight1 ev5 gra9$1 cle> spruce4 ,x %all be air season$1 pref]ably = two ye>s4 ,kiln dri$ wood is n acceptable4 ,x is highly desirable to h all bolts1 p9s1 plate fitt+s & turnbuckle ends made ( *rome vanadium /eel 7,s4 ,a4 ,e4 ,specification #f4acj71 heat treat$ to obta9 ! be/ physical *>act]i/ics4 ,all p>ts & fitt+s t mu/ be b5t %all be heat treat$ aft] all b5d+ op]ations are complet$1 & by su* a sequ5ce ( treatm5t z w produce ! desir$ gra9 & t\ghness1 & relieve all /resses due to ! b5d+4 ,?is includes %eet & =g$ /eel fitt+s1 turnbuckle ends & bolts & p9s4 ,all /eel p>ts & fitt+s submitt$ to /ress or vibration %all be heat treat$ 9 su* a mann] z to produce ! highe/ possible ref9em5t ( gra9 & give ! greate/ possible resi/ance to alt]nat+ & vibratory /resses4 ,:]e plate fitt+s are 9 contact ) wood5 memb]s1 %>p edges next to ! wood %all be remov$4 ,9 mak+ up & connect+ /eel fitt+s1 weld+ %all be us$ :]ev] possible4 ,if impracticable to weld1 & 9 su* cases only1 braz+ w be us$1 prop] heat treatm5t to be employ$ to re/ore /r5g? & t\ghness ( metal aft] su* weld+ or braz+4 ,extreme c>e %\ld be tak5 to avoid nick+ or k9k+ any wire1 cable or fitt+4 ,fitt+s1 %eet or =g$1 mu/ be free f %>p corn]s & suppli$ ) g5]\s fillets4 ,9 g5]al ! ,s4,a4,e4 ,/&>ds w be acceptable1 & ^! /&>ds = screw ?reads %all be us$ :]ev] possible4 ,u4,s4 ,/&>d ?reads w be accept$ :]e ?read$ into ca/ iron1 ca/ alum9um or copp] alloys4 ,all nuts & p9s mu/ be provid$ ) "o or m positive & durable safety devices4 ,9 g5]al1 :]e x mu/ be expect$ t a /ructural fitt+ w be disassembl$ a numb] ( times dur+ ! life ( ! a]oplane1 ca/ellat$ nuts ) split p9s1 9 accordance ) ,s4,a4,e4 ,/&>ds1 %all be us$4 ,:]ev] ?is is n ! case1 p9s or bolts %all be rivet$ 9 a workmanlike mann]4 ,seats %all be securely brac$ aga9/ bo? horizontal & v]tical /resses4 ,arrangem5t & dim5sions ( cock-pits %all be z ne>ly z practicable to t indicat$ by ! draw+s 7n publi%$ 9 ?is *apt]74 ,9 addition1 if practicable1 ! pilot %\ld be provid$ ) quick release arm re/s4 ,sections ( be/ grade ( khaki on ea* side ( seats1 9 :i* pockets are made1 %\ld be fa/5$ to long]ons & v]tical po/s 9 su* a way z to be securely 9 place & yet readily deta*able = inspection ( /ructural wir+ & fitt+s4 ,safety belts %all be provid$ = bo? seats & securely fa/5$4 ,! belts %all safely support at any po9t a load ( #b1jjj p\nds appli$ z 9 practice4 ,rubb] %ock absorb]s 9 ! safety belt sy/em are consid]$ to be an advantage4 ,! quick release device %all be z indicat$ 9 draw+s & %all reliably & quickly function4 ,seat pads %all be quickly deta*able 9 ord] t !y may be us$ z life pres]v]s4 ,!y w be fill$ ) ,kapok or o!r simil> mat]ial & cov]$ ) real lea!r to protect x aga9/ ! action ( salt wat]4 ,suitable cov]s %all be provid$ ov] ! top ( ! re> end ( ! fuselage4 ,^! mu/ be easily remov$ & capable ( be+ securely fa/5$ 9 place dur+ flight4 ,space %all be all[$ 9 ! body directly 9 ! re> ( ! obs]v]'s seat = ! /[age ( ! sea an*or4 ,:5 9 use1 ! sea an*or %all be atta*$ by suitable & conv5i5t fa/5+ hooks to ! two po9ts along ! l[] long]ons1 & at ! junction ( ! two v]tical /ruts 9 ! re> ( ! front seat4 ,! /ructure mu/ be su* t x w successfully )/& ! /resses impos$ by ! sea an*or4 ,controls %all be ( ! /&>d ,dep]duss9 type1 in/all$ 9 ! re> cock-pit only4 ,! tanks = ! ma9 supply ( gasol9e %all be 9 ! fuselage & locat$ s t ! longitud9al balance w n be di/urb$ by ! empty+ ( ! tank dur+ flight4 ,! above data is n 9 ! exact =m ( ! orig9al specifications & is n complete1 b gives only ! specifications t affect ! design ( ! body4 ,^! 7 pick$ out "p by "p f ! orig9al4 99,army ,specification #ajjc 7,spe$ ,sc\t7994 ,^! specifications cov] ! design ( l& ma*9es1 ! extracts giv5 "h ref]r+ only to ! safety factor4 ,body =w>d ( ! cockpit %all be design$ = safety factor ( #aj ov] /atic conditions1 ) ! propell] axis horizontal4 ,body 9 re> ( cockpit %all be design$ to fail "u loads n less ?an ^? impos$ "u ! foll[+ conditions3 7a7 ,dynamic load+ ( #e z ! result ( quick turns 9 pull+ out ( a dive4 7b7 ,sup]pos$ on ! above dynamic load+ %all be ! load :i* x is possible to impose ^u ! elevators1 comput$ by ! foll[+ =mula3 ,l #j4jje;,,av1 :]e ,a is ! total area ( ! /abiliz+ surface 7elevators & fix$ surface71 & ,v is ! horizontal high spe$ ( ! ma*9e4 ,! units are all 9 ! metric sy/em4 7c7 ,sup]pos$ on ?is load+ %all be ! =ce 9 ! control cables produc+ compression 9 ! long]ons4 99,fuselage ,cov]+994 ,disreg>d+ ! monocoque & v5e] con/ruct$ types ( fuselage1 ! mo/ common me?od ( cov]+ consi/s ( a metal %ell 9 ! =w>d end1 & a dop$ l95 cov]+ = t portion ( ! body t lies to ! re> ( ! re> seat4 ,! metal %ea?+1 :i* may be ( %eet /eel or %eet alum9um1 g5]ally runs f ! extreme front end to ! re> ( ! pilot's cockpit4 ,%eet /eel is m common ?an alum9um because ( its /iffness4 ,milit>y ma*9es are usually protect$ 9 ! =w>d portions ( ! fuselage by a ?9 armor plate ( ab\t #c millimet]s 9 ?ickness4 ,?is is a protection aga9/ rifle bullets & %rapnel fragm5ts1 b is ( little avail aga9/ ! heavi] projectiles4 ,armor is ne>ly always omitt$ on spe$ sc\ts because ( its weight4 ,bomb]s ( ! ,h&ley-,page type are v heavily plat$ & ?is %ell c resi/ q l>ge calib]s4 ,! fabric us$ on ! re> portion ( ! fuselage is ( l95 simil> to ! w+ cov]+1 & l ! w+ fabric is well dop$ ) "s cellulose comp\nd to resi/ moi/ure & to produce %r9kage & tautness4 ,on ! sides & bottom ! fabric is support$ by v ?91 light /r+]s atta*$ to ! fuselage /ruts4 ,on ! top1 ! face is g5]ally curv$ by support+ a numb] ( closely spac$ /r+]s on curv$ wood5 =m]s4 ,! =m]s are g5]ally arrang$ s t !y c be easily remov$ = ! inspection ( ! wire /ay connections & ! control leads4 ,on "s ma*9es ! top ( ! fuselage consi/s entirely ( %eet metal support$ on =m]s1 :ile 9 o!rs ! metal top only ext5ds f ! motor to ! re> ( ! re> cockpit4 ,,*apt] ,,xiii4 ,,*assis ,,con/ruction4 99,g5]al ,notes994 ,! *assis or l&+ ge> c>ries ! weight ( ! a]oplane :5 re/+ on or runn+ ov] ! gr\nd1 & is subject$ to v heavy %ocks1 especially :5 l&+4 ,x is provid$ ) pneumatic tir$ :eels1 an ela/ic %ock absorb+ device1 & ! /ructural memb]s t connect ! axle ) ! fuselage4 ,9 "s =ms ( l&+ ge>1 ! :eels are supplem5t$ by long horizontal skids :i* s]ve to support ! ma*9e aft] ! ela/ic %ock absorb]s are fully ext5d$ or :5 ! :eels collapse4 ,! skids also protect ! a]oplane 9 cases :]e ! :eels run into a dit* & also prev5t ! ma*9e f nos+ ov] 9 a bad l&+4 ,s9ce ! skids & _! /ructural memb]s cause a high resi/ance !y are n[ seldom us$ except on ! l>g] & sl[] ma*9es4 ,9 runn+ ov] ! gr\nd1 or 9 mak+ a h>d l&+1 "p ( ! %ock is tak5 up by ! deflection ( ! tires & "p by ! deflection ( ! %ock absorb]4 ,! great] ! movem5t ( ! tires & absorb]1 ! less w be ! /ress 9 ! frame4 ,9 ! majority ( cases1 ! %ock absorb]s consi/ ( rubb] b&s or cords1 ^! be+ w\nd ov] ! axle & "u a /ation>y "p ( ! *assis memb]s4 ,s9ce rubb] is capable ( absorb+ & dissipat+ a great] am\nt ( en]gy p] p\nd ( weight ?an /eel1 x is ! mo/ commonly us$ mat]ial4 ,rubb] causes mu* less reb\nd or kick ?an /eel spr+s4 ,! pr9cipal objection to rubb] is its rott+ "u ! influ5ce ( sunlight1 or :5 9 contact ) lubricat+ oil4 ,! movem5t ( ! axle tube is g5]ally con/ra9$ by a slott$ guide or by a %ort radius rod4 ,! design ( a suitable *assis is q a complicat$ problem1 = ! /resses are sev]e1 & yet ! weight & resi/ance mu/ be kept at a m9imum4 ,9 runn+ ov] r\gh or s(t gr\nd = ! ,get (f1 ! %ocks & vibration mu/ be absorb$ )\t excessive /ress 9 ! framework1 & )\t di/urb+ ! balance or poise ( ! ma*9e4 ,!re mu/ be little t5d5cy t[>d nos+ ov]1 & ! ma*9e mu/ be balanc$ ab\t ! tread s t side gu/s h little t5d5cy 9 ?r[+ ! ma*9e out ( its pa?4 ,x mu/ be simple & easily repair$1 & ! :eels mu/ be l>ge en\gh to roll easily ov] mod]ately r\gh gr\nd4 ,illu/ration3 ,fig #a4 ,v ,type ,*assis z ,appli$ to ,z5s ,monoplane4 ,c\rtesy ,flight4 99,types ( ,*assis994 ,! simple/ & mo/ ext5sively us$ l&+ ge> is ! ,vee type %[n by ,fig4 #a1 & is equally applicable to monoplanes1 biplanes or triplanes4 ,prim>ily1 ! ,vee *assis consi/s ( two :eels1 an axle1 a rubb] %ock absorb]1 & two sets ( ,vee =m /ruts4 ,! *assis %[n by ,fig4 #a-;a is t ( ! ,hansa-,br&5burg & is typical ( biplane *assis4 ,! w9d+ ( ! rubb] cord & ! arrangem5t ( ! *assis /ruts are cle>ly %[n4 ,! two /ruts are connect$ at ! bottom by a metal fitt+1 & ! rubb] is w\nd ov] ! axle & "u ?is fitt+4 ,no guid+ device is us$ = ! axle1 ! ma*9e be+ freely susp5d$ by ! *ord4 ,! /ruts are made z ne>ly /reaml9e =m z possible4 ,illu/ration3 ,fig #a;a4 ,v ,type ,*assis ,us$ on ,hansa-,br&5b]g ,biplane4 ,fig4 #b is a front view ( a typical ,vee *assis1 & ,fig4 #c is side view ( ! same device1 ! same ref]5ce lett]s be+ us$ 9 ea* view4 ,! v]tical /ruts ,c run f ! fuselage at ,f to ! connect+ axle guide plate ,g4 ,! :eels ,w-,w are connect$ ) ! /eel tube axle ,a1 & ! /ruts are brac$ aga9/ side ?ru/ by ! cross-tube ,d & ! /ay wire braces ,b-,b4 ,9 ,fig4 #c ! metal fitt+ ,g is provid$ ) ! guid+ slot ,s = ! axle ,a4 ,! ela/ic rubb] cord absorb] passes ov] ! axle & is fa/5$ to ! plate ,g by ! /uds ,i4 ,fig4 #d is a side view ( ! *assis ( ! ,lawson tra9]1 :i* l _m o!r prim>y tra9+ ma*9es1 uses a front pilot :eel to gu>d aga9/ nos+ ov]4 ,! re> two :eels 7,w7 are ela/ically support$ betwe5 ! ,vee /ruts ,c & ,f1 :ile ! front :eel ,x is atta*$ to ! fuselage by ! v]tical /rut ,e1 & to ! re> :eel frame by ! tube ,g4 ,x w be not$ t ! front :eel is small] ?an ! re> ma9 :eels1 z ?is :eel c>ries b little load4 ,! tail skid ,t is h+$ to ! fuselage & is provid$ ) ela/ic cord at ! upp] end s t ! %ock is r$uc$ :5 ! tail /rikes ! gr\nd4 ,fig4 #e %[n directly above ! ,lawson tra9]1 is ! complete assembly ( ! ,hansa-,br&5burg already describ$4 ,! tail skid ( ! ,hansa-,br&5burg is indicat$ by ,t4 ,illu/ration3 ,figs4 #b-c4 ,typical ,v ,*assis ,) ,axle ,guide4 ,! metal %od a% skid /ick is h+$ to ! l[] face ( ! fuselage1 & at ! upp] end is atta*$ to a /ation>y fuselage memb] ?r\gh f\r turns ( ela/ic cord4 ,:5 ! skid /rikes an ob/acle ! rubb] gives & all[s ! tail to move 9 relation to ! gr\nd4 ,by ?is arrangem5t ! great] "p ( ! device is enclos$ )9 ! fuselage &1 h5ce1 produces little head resi/ance4 ,illu/ration3 ,fig #d4 7,bel[74 ,lawson ,tra9+ ,tractor ,biplane4 ,fig4 #e 7,above74 ,hansa-,br&5burg ,fight+ ,biplane ,%[+ ,*assis & ,tail ,skid 7t74 ,fig4 #g is ! skid *assis ( ! ,f>man biplane :i* %[s cle>ly ! arrangem5t ( ! skids & ! %ock absorb+ susp5sion4 ,a metal bridge is atta*$ to ! axle1 & a s]ies ( %ort rubb] b&s are us$ 9 connect+ ! axle bridge1 & ! bridge on ! skid4 ,a triangul> tubul> radius rod is atta*$ to ! axle & h+$ to ! skid4 ,?is re/ra9s ! travel ( ! axle 9 a =e & aft direction4 ,ano!r =m ( skid %ock absorb] is giv5 by ,fig4 #h1 9 :i* ! rubb] r+s pass ov] a spool on ! axle4 ,! guid+ l9ks or radius rods on ! inside ( ! skids regulate ! axle travel4 ,9 g5]al1 ! use ( a radius rod is n desirable z x transmits a p]c5tage ( ! %ock to ! ma*9e4 ,illu/ration3 ,fig4 #g4 7,left74 ,f>man ,skid ,type ,*assis4 ,fig4 #h4 ,ano!r ,type ( ,skid ,*assis 9 ,:i* ! ,axle ,is ,guid$ by a ,radius ,rod or ,lev]4 ,illu/ration3 ,fig4 #i4 ,*assis ,details ( ! ,nieuport ,monoplane4 ,?is ,has a ,c5tral ,skid & ,uses an ,automobile ,type ,/eel ,spr+ ,in/ead ( ,rubb] ,cord4 ,fig4 #aj ,is a ,detail ( ! ,nieuport ,spr+4 7,at ,"r47 ,fig4 #i is an old] =m ( ,nieuport monoplane *assis1 a /eel cross spr+ be+ us$ 9 place ( ! usual rubb] b&s4 ,?is is simple1 b comp>atively heavy1 & is subject to frequ5t spr+ breakage4 ,to gu>d aga9/ spr+ failure1 a long a% skid is plac$ "u ! axle4 ,! spr+ sy/em is connect$ ) ! body by ?ree sets ( oval /eel /ruts4 ,an old type ( ,curtiss *assis is giv5 by ,fig4 #aa4 ,?is has be5 widely us$ by amateurs & exhibition fly]s1 b requires a fairly smoo? l&+ gr\nd z !re are no %ock absorb]s4 ,! only %ock absorption is t due to ! deflection ( ! tires4 ,! extreme =w>d position ( ! front :eel effectually prev5ts any t5d5cy t[>d nos+ ov] :5 l&+4 ,illu/ration3 ,fig4 #aa4 ,an ,old ,type ( ,curtiss ,exhibition ,*assis ,) ,?ree ,:eels4 ,illu/ration3 ,fig4 #ab 7,left74 ,/&>d ,h-#c ,%ock ,absorb]4 ,fig4 #ac4 7,"r74 ,rubb] ,cord on ,axle4 ,a ,/&>d ,h-#c %ock absorb+ sy/em is giv5 by ,fig4 #ab4 ,?is has a bracket or hang] atta*$ to ! axle ov] :i* ! ela/ic cord is wrapp$4 ,! cord is wrapp$ 9 cont9u\s turns betwe5 ! axle hang] & ! bottom ( ! ,vee support memb]s4 ,z %[n1 ! upp] /reaml9$ b> is ! axle1 :ile ! l[] is ! cross b> brace :i* s]ves to hold ! l[] ends ( ! ,u's4 ,i am indebt$ to ,a]ial ,age = ?is cut4 ,9 ord] to guide ! axle 9 a /raight l9e 9 its up & d[n movem5t1 two radius l9ks are atta*$ betwe5 ! axle & ! front v]tical /rut4 ,"o decid$ advantage ( ! ,/&>d con/ruction is t ! cords are w\nd )\t cross+ ! /r&s1 ?us r$uc+ cutt+ & we> betwe5 ! cord turns4 ,fig4 #ac is a v>iation ( ,fig4 #ab1 ! cord be+ w\nd directly ar\nd spools on ! axle & ! l[] /ation>y cross tube4 ,! axle is guid$ by a slot 9 ! guide plate at ! "r1 :ile end motion is controll$ by a radius l9k4 ,fig4 #ad is ! d\ble :eel arrangem5t ( a l>ge ,tw9 bomb+ plane4 ,two :eels are plac$ directly "u ea* ( ! motor units s t a portion ( ! load is communicat$ to ! *assis by tubes4 ,diagonal tubes transmit ! body load to ! *assis4 ,illu/ration3 ,fig4 #ad4 ,*assis = ,tw9 ,motor$ ,biplane ( ,bomb+ ,type4 99,fold+ ,*assis994 ,ow+ to ! great relative resi/ance ( ! *assis x has be5 sugge/$ by _m design]s to provide a fold+ frame :i* w automatically fold up into ! body aft] ! ma*9e has left ! gr\nd4 ,?is w\ld be a decid$ advantage b ! ge> is complicat$ & probably n altoge!r reliable4 99,height ( ,*assis994 ,! height ( ! *assis is made z small z possible ) a suffici5t cle>ance = ! propell] tips4 ,x is usual to h ! tips ( ! propell] blades cle> ! gr\nd by f #aj to #ab in*es :5 ! a]oplane is /&+ ) ! body 9 a horizontal position4 ,any small] cle>ance is almo/ c]ta9 to result 9 brok5 blades :5 l&+ at a %>p angle or :5 runn+ ?r\gh high grass4 ,if ! *assis is excessively high ! resi/ance w be high & ! ma*9e is also likely to be top heavy4 ,illu/ration3 ,figs4 #ae-af4 ,me?ods ( ,calculat+ ,:eel ,position on ,two ,:eel ,*assis4 ,?is ,is an ,important ,item 9 ! ,design ( an ,a]oplane4 99,location ( ,:eels994 ,! exact location ( ! :eels1 9 a =e & aft direction1 is ( ! greate/ importance4 ,if !y are too f> ahead ( ! c5t] ( gravity1 too mu* weight w be plac$ on ! tail skid & excessive runn+ w be requir$ to get ! tail (f ! gr\nd4 ,if ! :eels are too f> back1 ! ma*9e w be likely to nose ov] :5 l&+ or runn+ ov] ! gr\nd4 ,9 any case1 ! :eels mu/ be well ahead ( ! c5t] ( gravity s t ! weight w resi/ a =w>d ov]turn+ mom5t4 ,9 ! majority ( or?ogonal biplanes1 9 :i* ! lead+ edges ( ! upp] & l[] w+s are on ! same v]tical l9e1 ! c5t] ( ! :eel is f #c to #f in*es back ( ! lead+ edges4 ,9 /agg]$ biplanes ! :eel c5t] is f #f in*es to "o foot 9 front ( ! l[] lead+ edge4 ,?is diff]5ce is caus$ by ! fact t ! c5t] ( gravity is ne>] ! lead+ edge ( a /agg]$ w+ ?an ) ! ,or?ogonal type1 & h5ce ! :eels mu/ be fur!r =w>d4 ,fig #ae 7upp] diagram7 %[s ! conditions :5 ! ma*9e is runn+ ov] ! gr\nd ) ! body horizontal4 ,! v]tical l9e a-a pass+ ?r\gh ! c5t] ( gravity ,c ,g is a di/ance ,n f ! c5t] ( ! :eel4 ,! weight act+ d[n has a t5d5cy to pull ! tail d[n1 ?is mom5t be+ equal to ! weight ( ! ma*9e multipli$ by ! di/ance ,n1 or ,w x ,n4 ,! elevator flap ,m ex]ts a lift+ =ce ,ky :i* acts ?r\gh ! lev] arm ,l1 & opposes ! mom5t due to ! weight4 ,! =ce ,k mu/ be equal to ,k ,,wn_/,l4 ,! di/ance ,i is ! di/ance ( ! :eel c5t] l9e f ! ent]+ edge ( ! w+4 ,! weight on ! tail skid ,s :5 ! ma*9e is re/+ on ! gr\nd w be equal to ,s ,,wn_/,m1 & ?is may range any:]e f #dj to #bjj p\nds1 accord+ to ! size ( ! a]oplane4 ,fig4 #af illu/rates a pr9ciple ( :eel location advanc$ by ,capt4 ,byron ,q4 ,jones1 & publi%$ 9 ,aviation & ,a]onautical ,eng9e]s1 ,nov4 #af1 #aiaf4 ,! body is %[n 9 a horizontal position ) ! propell] axis ,x-,x horizontal4 ,! c5t] ( gravity is at ,g on ,x-,x1 ! weight act+ d[n z at ,p ) ! l9e prolong$ meet+ ! gr\nd l9e at ,b4 ,a l9e ,e-,e is a l9e drawn tang5t to ! :eels & ! tail skid at ,d1 ! angle ( ?is l9e ) ! gr\nd det]m9+ ! maximum angle ( incid5ce4 ,e-,e is ! gr\nd l9e :5 ! ma*9e is at re/4 ,= ! be/ conditions1 ,capt4 ,jones f9ds t ! l9e connect+ ! po9t ( tang5cy ,c1 & ! c5t] ( gravity at ,g1 %\ld make an angle ( #ac degrees & #aj m9utes ) ! v]tical ,,gb dropp$ ?r\gh ! c5t] ( gravity4 ,) ! l9e ,,ga drawn p]p5dicul> to ! re/+ l9e ,e-,e1 ! angle ,,bga %\ld be #aj degrees z ne>ly z possible4 ,?is is = a two-:eel ,vee *assis1 b ) a ?ird front :eel z ) ! tra9+ ( type ! angle ,,cgb c be made less4 ,capt4 ,jones has f\nd t ) ! :eels 9 ! above location !re w be no t5d5cy to nose ov] ev5 ) v poor l&+s1 & ?is me?od has be5 appli$ to ! tra9+ ma*9es at ! ,san ,diego ,signal ,corps aviation s*ool4 ,if ! angle ,,bga is great] ?an #aj degrees x is difficult to taxi ! ma*9e on ! gr\nd1 ?is t5d+ to make ! ma*9e sp9 or turn into ! w9d4 ,capt4 ,jones claims t a two-:eel *assis arrang$ accord+ to ^! rules is sup]ior to ! ?ree-:eel type = tra9+ purposes s9ce ! t5d5cy t[>d sp9n+ is less4 ,! location ( ! tail skid ,s %\ld be su* t ! elevator & rudd] surfaces are well (f ! gr\nd ) ! skid fully deflect$1 & yet ! skids mu/ be l[ en\gh to p]mit ( ! maximum angle ( incid5ce or an angle ( ,,exx #aj degrees4 ,to a c]ta9 ext5t1 ! maximum angle ( incid5ce det]m9es ! *assis height4 ,if ! angle ,,exx is made great] ?an ! greate/ angle ( incid5ce1 ! w+s c be us$ z air brakes 9 br++ ! ma*9e to a quick /op aft] l&+4 ,! track1 or ! di/ance betwe5 ! c5t]s ( ! :eels measur$ along ! axle1 mu/ be ab\t #a_/g or #j4ae ( ! span ( ! l[] w+4 ,?is makes ! track v>y f #e to #g feet on ! usual types1 & z high z #ae feet on ! l>ge bomb+ planes4 ,! track mu/ be great en\gh to prev5t ov]turn+ :5 mak+ a l&+ on s(t gr\nd or ) a cross w9d4 ,if ! track is excessive1 !re w be a heavy sp9n+ mom5t 9 cases :]e "o :eel /rikes a depression or s(t spot 9 ! gr\nd4 99,%ock ,absorb]s994 ,! axle movem5t all[$ by ! ela/ic %ock absorb]s & guid+ appliances av]ages f #e to #f in*es4 ,! great] ! movem5t1 ! less w be ! /resses induc$ by a giv5 drop1 b 9 practice ! movem5t is g5]ally limit$ by consid]ations ( *assis height & propell] cle>ance4 ,x c be prov$ t a movem5t ( #e in*es w produce a maximum /ress equal to #h4f times ! weight ( ! ma*9e "u conditions ( a "o-foot drop1 :ile ) an absorb] movem5t ( #f in*es ! /ress is r$uc$ to #g4e times ! weight4 ,?is calculation takes ! tire deflection into consid]ation4 ,) ! absorb] movem5t limit$ to "o in*1 ! /ress may be z high z #ce times ! weight ( ! ma*9e4 ,f,w 7#b #b4gg_/x7 :]e ,w weight ( ma*9e 9 p\nds1 ,f ! /ress produc$ by ! fall1 & x ! absorb] movem5t 9 in*es4 99,l&+ ,ge> ,:eels994 ,! :eels are g5]ally ( ! tang5t lac$ wire spoke type1 & are enclos$ ) discs to r$uce ! resi/ance4 ,!y mu/ h v wide hubs to resi/ ! heavy end /resses caus$ by l&+ sidewise4 ,! l5g? ( ! hub %\ld be at lea/ twice ! diamet] ( ! tire & a great] wid?1 say ?ree times ! tire diamet]1 is pref]able4 ,! n>r[ hubs us$ on motorcycle :eels are n safe aga9/ side bl[s1 al?\gh !y may be capable ( )/&+ ! v]tical load4 ,! :eels are rat$ accord+ to ! outside diamet] ov] ! tire1 & by ! diamet] ( ! tire cas+4 ,a #bf x #d :eel signifies t ! outside diamet] is #bf in*es ) a cas+ diamet] ( #d in*es4 ,! #bf x #d tires are us$ on ! majority ( tra9+ ma*9es ( ! two-:eel type1 :ile a #bj x #d :eel is us$ = ! front :eel ( ! ?ree-:eel tra9]4 ,two l>g] sizes1 #cj x #d & #cd x #d1 h also be5 us$ to "s ext5t1 p>ticul>ly on ! ,ack]man spr+ :eels4 ,,*apt] ,,xiv4 ,,e/imation ,,( ,,weight4 99,effect ( ,weight994 ,weight is an all important consid]ation & is mo/ difficult to e/imate unless "o has accurate data on exi/+ ma*9es ( ! same type4 ,! total weight 9 fly+ ord] dep5ds ^u ! useful load to be c>ri$1 & ^u ! weight ( ! p[] plant4 ,! weight ( ! latt] v>ies bo? ) ! useful load & ) ! spe$1 climb1 & duration ( flight4 ,! type ( a]oplane det]m9es ! relative head resi/ance :i* aga9 reflects back to ! weight ( ! p[] plant4 ,! only reason = ! exi/5ce ( an a]oplane is to c>ry a c]ta9 useful load = a giv5 di/ance1 & ?is useful load is ! basis ( our weight calculations4 ,! basic useful load consi/s ( ! pass5g]s & c>go1 al?\gh 9 "s specifications ! live load may be con/ru$ z includ+ ! weight ( ! fuel1 oil & in/rum5ts1 & 9 ! case ( milit>y a]oplanes1 ! weight ( ! armam5t1 armor1 ammunition1 wireless & cam]as4 ,= comp>ison1 ! elem5ts con/itut+ ! live load %\ld always be specifi$4 ,= a giv5 horsep[]1 spe$ & climb1 x is obvi\s t ! dead or /ructural weight %\ld be at a m9imum = a maximum live load capacity4 ,! dead load c>ri$ 9 pres5t a]oplanes w be und\bt$ly r$uc$ 9 ! future by ! adoption ( light] & /rong] mat]ials1 bett] me?ods ( brac+1 & by r$uctions 9 ! weight ( ! p[] plant4 ,j z ! automobile indu/ry develop$ light & p[]ful mat]ials ( con/ruction1 s w ! a]oplane design] develop m suitable mat]ials = ! aircraft4 ,:ile ! pres5t p[] plant has be5 ref9$ to a rem>kable ext5t :5 comp>$ ) ! old] types1 x is /ill f> f ! l[e/ possible limit4 ,at pres5t ! complete p[] unit--! motor1 radiator1 propell]1 wat]1 etc4--w weigh f #b to #e p\nds p] horsep[]4 ,) a giv5 a]oplane1 ! p]=mance is det]m9$ by ! total weight & p[]4 ,! duration & flight range c be increas$ by increas+ ! fuel weight at ! exp5se ( ! pass5g] or c>go weight4 ,! p[] available = climb+ is ! excess ( ! total p[] ( ! motor ov] ! p[] requir$ = horizontal flight4 ,s9ce ! p[] = horizontal flight dep5ds pr9cipally ^u ! weight1 x is at once evid5t t ! weight is a regulat+ factor 9 ! climb+ spe$4 ,9 fact ! climb+ spe$ may be almo/ directly det]m9$ f ! weight c>ri$ p] horsep[] at normal flight spe$4 ,a fa/ climb+ sc\t may weigh f #h to #ab p\nds p] horsep[]1 :ile ! l>ge l[ climb+ ma*9e w weigh f #af to #bj p\nds p] horsep[]1 ! respective climb+ spe$s be+ approximately #a1bjj & #cej feet p] m9ute4 99,fuel ,effici5cy & ,weight994 ,! effici5cy ( ! motor1 or its fuel consumption = a giv5 output1 has a v m>k$ effect ^u ! total weight ( ! a]oplane4 ,"u c]ta9 conditions a v light motor ) a high fuel consumption w (t5 contribute m to ! total weight ?an a heavi] b m economical motor4 ,9 %ort flights1 up to #c h\rs1 ! v light rotat+ cyl9d] motor ) its high fuel consumption probably gives ! lea/ total weight1 b = long] flights ! m effici5t & heavi] wat]-cool$ type is pref]able4 ,= flights ( ov] ?ree h\rs ! fuel weight is a consid]able p]c5tage ( ! total weight4 ,! prop] motor = any ma*9e mu/ be select$ by comput+ ! weight ( ! fuel & oil requir$ = a giv5 duration & !n add+ ?is to ! total weight ( ! eng9e & its cool+ sy/em4 99,di/ribution ( ,weight994 ,practically ! only way to pr$ict ! weight ( a propos$ ma*9e is to comp>e x ) a simil> exi/+ type4 ,aft] ! ratio ( ! useful load to ! total load has be5 det]m9$1 ! useful load ( ! propos$ ma*9e c be divid$ by ! ratio factor to obta9 ! total weight4 ,x %\ld be not$ 9 ?is reg>d t if ! propos$ ma*9e is mu* l>g] ?an ! ne>e/ exi/+ example1 a lib]al all[ance mu/ be made to comp5sate = ! increase 9 ! proportional weight ( ! /ructural memb]s4 ,!re h be5 _m ma!matical =mulas advanc$ = pr$ict+ ! weight1 b ^! are v inaccurate 9 ! majority ( cases4 ,z a r\gh e/imate1 bas$ on a numb] ( successful ma*9es1 ! weight ( ! actual a]oplane /ructure )\t p[]-plant1 live load1 fuel1 oil1 or tanks1 is v ne>ly #cb p] c5t 7#j4cb7 ( ! total weight4 ,! rema9+ #fh p] c5t is divid$ up among ! p[]-plant1 fuel & live load4 ,?us1 ! a]oplane /ructure prop] ( a ma*9e weigh+ #bjjj p\nds total w be #bjjj x #j4cb #fdj p\nds4 ,tak+ ! weight ( ! p[] plant1 tanks & pip+ at #bh p] c5t1 ! total dead load ( ! b>e ma*9e )\t fuel or oil w be #fj p] c5t ( ! total4 ,) a tra9+ a]oplane built = a #f-;h\r flight1 ! fuel & oil w approximate #af p] c5t1 s t ! total p]c5tage possible = ! crew & c>go w be #bd p] c5t4 ,) a giv5 live load1 ! total load c n[ be calculat$ by divid+ ! live load by its p]c5tage4 ,us+ ! above value1 = example1 ! total weight 9 ord] ( flight ) a live load ( #gbj p\nds becomes3 ,w #gbj_/j4bd #cjjj p\nds4 ,9 gov]nm5t specifications ! total weight ( ! pilot & pass5g] are tak5 at #ccj p\nds1 or #afe p\nds p] man4 ,gasol9e & oil are = a #d-;h\r flight4 ,a saf] av]age figure w be #agj p\nds p] man1 & a fuel all[ance ( #f h\rs4 ,! floats ( a seaplane or fly+ boat br+ ! p]c5tage ( ! dead load mu* high] ?an ) ! l& type ( *assis4 ,! foll[+ table w give an idea z to ! weight di/ribution express$ bo? 9 p\nds1 & z a p]c5tage ( ! total weight4 ,x cov]s a wide range ( types1 v>y+ f ! tra9+ types ,curtiss ,,jn-#d;,b & ! ,/&>d ,h-#c1 to ! ,h&ley-,page ,giant bomb] & ! ,nieuport spe$ sc\t4 ,! av]age values f\nd by ,hunsak] = a numb] ( ma*9es weigh+ 9 ! neighborhood ( #bejj p\nds is giv5 9 ! f\r? column4 ,"u ea* head+ are ! actual weights & ! p]c5tages ( ! total weight = ea* item4 ,items m>k$ 7997 include bo? gasol9e & oil4 ,m>k 7,c7 is ! p[] plant complete1 & 77 includes radiator4 99,weight ,p] ,horsep[]994 ,z already expla9$1 ! weight c>ri$ p] horsep[] v>ies ) ! type ( ma*9e4 ,:5 ! total weight is det]m9$ = any a]oplane1 ! p[] requirem5ts c be calculat$ by divid+ ! total weight by ! weight p] horsep[] ratio4 ,a fair value = a tra9+ or exhibition ma*9e is f #ah to #bj p\nds p] horsep[]1 :ile = a v high spe$ ma*9e1 su* z a *as]1 ! weight w be tak5 at #aj p\nds p] horsep[]4 ,= two-seat] fight]s #af to #ah p\nds is fair practice4 ,= a comp>ison ( ! horsep[]-weight ratios us$ on diff]5t well-kn[n ma*9es see tables 9 ,*apt] ,,ii4 ,?us1 if our total weight is f\nd to be #bdjj p\nds z det]m9$ f ! above table1 & if ?is is a tra9+ ma*9e1 ! horsep[] w be3 #bdjj_/bj #abj horsep[]4 ,us+ ! same total weight1 b p[]$ = two-seat] fight] conditions1 ! p[] w be increas$ to #bdjj_/af #aej horsep[]4 ,z a sc\t ! p[] w be increas$ /ill fur!r to #bdjj_/ajbdj horsep[]4 ,z a problem 9 solv+ ! weight & horsep[] f ! data1 we w assume t we are to design a two-seat] fight] ) a total useful load ( #abjj p\nds4 ,?is load consi/s ( ! foll[+ items3 ,p]sonnel 7#b7 #ccj p\nds2 gas & oil #ejj p\nds2 guns & ammunition #cgj p\nds4 ,! ne>e/ example t we h to ?is live load is t ( ! ,/&>d ,h-#c1 :i* c>ries #gdd p\nds & 9 :i* ! p]c5tage ( live load is #bh4a p] c5t4 ,z our ma*9e w be some:at l>g]1 we w n be f> f ! tru? if we take ! p]c5tage z #j4bg in/ead ( #j4bha4 ,! total weight1 9 fly+ ord]1 w n[ be #abjj_/j4bg #dddj p\nds4 ,at #af p\nds p] horsep[] ! motor w be3 #dddj_/afbgg horsep[]4 ,an empirical =mula = a high-spe$ sc\t 0 set =? 9 ,aviation & ,a]onautical ,eng9e]+ by ,d4 ,w4 ,d\glas4 ,?is is bas$ on ! horsep[] unit4 ,a unit w+ load+ ( #h4de p\nds p] squ>e foot1 & a l[ spe$ ( #ee miles p] h\r 0 assum$4 ,! w+ section *os5 0 ! ,u4,s4,a4-#a4 ,9 ! =mula1 ,h horsep[]3 - ,p[] plant weight #c ,h4 - ,*assis weight #j4g ,h4 - ,tail weight #j4be ,h4 - ,fuel = #b4be h\rs #a4d ,h4 - ,milit>y load #bej p\nds4 - ,tanks & pip+ #j4db ,h4 - ,fuselage weight #a4hd ,h4 - ,w+ weight #a lb4 sq4 ft4 - ,propell] #b4h_/;,h4 - 7,total7 7#g4fa ,h #b4e_/;,h #bej7_/g4de ,weight ( a]oplane fully load$ 9 ! ord] ( flight4 99,weight ( ,w+s994 ,! weight ( ! w+s dep5ds ^u ! span1 v small ma*9es hav+ w+s t weigh only #j4ch p\nds p] squ>e foot1 :ile ! w+s ( v l>ge ma*9es may run z high z #a4a p\nds p] squ>e foot4 ,= av]age size biplanes f #j4ge to #j4hj p\nds p] squ>e foot w\ld probably be safe--t is1 = areas rang+ f #dej to #eej squ>e feet4 ,! weight ( ! upp] w+ ( ! ,nieuport is #j4hae p\nds p] squ>e foot1 :ile ! l[] w+ 7%ort *ord7 is #j4fdf p\nds p] squ>e foot4 ,! w+s ( ! ,/&>d ,h-#c tra9] w av]age #j4gg p\nds p] squ>e foot1 ! l[] w+ & c5t] section be+ heavi] ?an ! upp] w+4 ,! w+s ( ! ,curtiss ,,jn-#d;,b w av]age #j4ge p\nds p] squ>e foot4 ,^! weights d n include ! int]plane wires or /ruts1 nor ! fitt+s4 ,! total weight ( ! int]plane /ruts ( ! ,,jn-#d;,b1 ! ,aviatic1 & ma*9es ( simil> size w av]age f #bh to #cj p\nds4 ,! ail]ons w weigh ab\t #ab p\nds ea*4 99,weight ( ,motors994 ,!re is a consid]able diff]5ce 9 ! weight ( air-cool$ & wat]-cool$ motors4 ,! wat]1 wat] pip+1 radiators & jackets ( ! wat]-cool$ motors adds consid]ably to ! weight ( ! complete p[] plant4 ,! m\nt+s are heavi] = ! wat]-cool$ motors1 & because ( ! t&em arrangem5t ( ! cyl9d]s1 ! crank%aft & crankcase weigh m4 ,9 tak+ ! b>e weight ( ! p[] plant all ( ! accessories mu/ be includ$4 ,9 ! foll[+ table1 ! b>e eng9e includes ! c>buret]1 magneto1 & necess>y integral accessories1 b does n include ! jacket wat]1 m\nt+1 radiator1 oil 9 base1 wat] pip+1 nor controls4 ,wat]-cool$ motors are m>k$ by 7,w7 & air-cool$ by 7,a74 ,rot>y air-cool$ are 7,,ra71 & gallons 7,g74 ,,weights ,,( ,,a]onautical ,,motors4 ,! b>e radiator w weigh f #j4dh to #j4ef p\nds p] horsep[]1 ! av]age be+ safe at #j4eb4 ,! wat] conta9$ 9 ! radiator w av]age #j4ce p\nds p] horsep[]4 ,! weights ( ! pip+ & ! wat] conta9$ !re9 w be comput$ sep>ately4 ,! circul> %eet metal c[l us$ ov] ! rot>y cyl9d] air-cool$ motor is equal to twice ! squ>e root ( ! motor weight1 accord+ to ,b>nwell4 ,propell] weight v>ies consid]ably ) ! diamet]1 pit*1 etc41 b a safe rule w give ! weight z #b4h ,h :]e ,h horsep[]4 ,! tanks w weigh f #j4ge to #a4b p\nds p] gallon ( cont5ts1 or approximately #a_/e ! weight ( ! cont5ts :5 completely fill$4 99,*assis & ,:eel ,weight994 ,! *assis ( a two-:eel tra9] w weigh ab\t #ij p\nds complete1 al?\gh !re are *assis ( tra9+ ma*9es t weigh z mu* z #adj p\nds4 ,! *assis ( spe$ sc\ts w be f #bb to #dj p\nds complete4 ,tail skids c be tak5 at f #f to #h p\nds4 ,tang5t wire :eels complete ) tires are ab\t z foll[s3 #bf x #d #ba p\nds2 #bf x #e #bh p\nds2 #bf x #c #ad p\nds4 ,ack]man spr+ spoke :eels are e/imat$ z foll[s3 #bj x #d #ag4e p\nds2 #bf x #c #bb p\nds2 #bf x #d #cb p\nds2 #cj x #d #ce p\nds2 #cd x #d #de p\nds4 99,milit>y ,loads994 ,a #bj-mile wireless outfit devis$ by ,capt4 ,culv] weigh$ #dj p\nds ) /orage batt]ies1 :ile ! #abj-mile outfit weigh$ #fj p\nds ) a #ahj-watt g5]ator4 ,! #adj-mile ,u4,s4,a4 mule-back wireless ( #aiab weighs #de p\nds4 ,! ,blimp specifications all[ #bej p\nds4 ,! ,lewis gun z m\nt$ on ! #aa ,nieuport weighs #aaj p\nds1 includ+ m\nt1 gun & ammunition4 ,lewis gun b>e is #bf p\nds4 ,! ,davis #f-p\nd]1 ,m>k ,,iv1 weighs #ajc p\nds ) m\nt+ b )\t ammunition1 :ile ! same make ( #c-;in* #ab-p\nd] weighs #bch p\nds "u ! same conditions4 99,controls & ,in/rum5ts994 ,! ,dep]duss9 type controls us$ on ! ,curtiss ,,jn-#d;,b weigh #af p\nds p] control1 :ile ^? in/all$ 9 ! ,/&>d ,h-#c weigh ab\t #ac p\nds4 ,an av]age ( #ae p\nds p] control is safe4 ,an in/rum5t bo>d = ! aviators' cock-pit1 fully equipp$1 weighs f #bj to #bd p\nds4 ,! front1 or /ud5ts' in/rum5t bo>d w av]age #aj p\nds4 ,pyr5e ext+ui%] & brackets #g p\nds2 ,speak+ tube #c p\nds2 ,oil pressure l9e & gage #c p\nds2 ,side pockets #c p\nds2 ,tool kit #aj p\nds4 99,control ,surfaces994 ,! rudd]1 /abiliz]1 f91 & elevator c be made s t ! weight w n exce$ #j4fj to #j4fe p\nds p] squ>e foot4 99,g5]al ,notes on ,weight994 ,be=e />t+ on ! weight e/imates ( ! ma*9e ! read] %\ld c>efully exam9e ! tables 9 ,*apt] ,,ii :i* give ! weights1 & g5]al *>act]i/ics ( a numb] ( mod]n ma*9es4 99,weights & ,w+ ,area994 ,:5 ! weight ( ! ma*9e is once det]m9$1 ! next /ep w be to det]m9e ! w+ area4 ,= spe$ sc\ts or v l>ge heavy duty ma*9es ! *oice ( a w+ section mu/ be v c>efully consid]$4 ,= ! spe$ sc\t sev]al w+s giv+ a m9imum high spe$ resi/ance %\ld be exam9$1 su* z ! ,eiffel #cg or ! ,u4 ,s4 ,a-#a or ,u4,s4,a4-#f4 ,= ! l[-spe$ a]oplane to be design$ = great lift1 a numb] ( sections su* z ! ,u4,s4,a4-#d or ! ,r4,a4,f4-#c %\ld be tri$ = a numb] ( spe$s & angles4 ,= tra9+ ma*9es a w+ ( ! ,all ar\nd type su* z ! ,r4,a4,f4-#f %\ld be adopt$1 ! /ructural *>act]i/ics 9 ! case ( a tra9] hav+ an important be>+ on ! subject4 ,if ,w weight ( ! ma*9e 9 p\nds1 ,v l[ spe$ 9 miles p] h\r1 ,a total area 9 squ>e feet1 & ,kylift coeffici5t1 !n ! area becomes ,a,w_/,ky,v4 ,comp5sation mu/ be made = biplane int]f]5ce = aspect ratio1 & /agg] z previ\sly expla9$4 ,= an ord9>y tra9+ ma*9e ) ! usual gap_/*ord ratio1 & aspect ratio1 ! correction factor ( #j4he may be safely employ$4 99,example994 ,we w take ! case ( an a]oplane c>ry+ a p]sonnel load ( #cdj p\nds1 oil & gasol9e #cgj p\nds1 & baggage am\nt+ to #aij p\nds1 in/rum5ts #ajj p\nds4 ,total live load w be #ajjj p\nds4 ,tak+ ! live load p]c5tage z #j4cj1 ! total load w be #ajjj_/j4cj #cccc p\nds4 ,if ! l[ spe$ is #ej miles p] h\r1 & ! maximum ,ky ( ! *os5 w+ is #j4jjc at ?is spe$1 ! area w be ,a ,w_/,ky,v #cccc_/j4jjc x 7#ej x #ej7 #ddd squ>e feet4 ,s9ce ?is is a biplane ) a correction factor ( #j4he1 ! correct$ area w be3 #ddd_/j4he #ebc squ>e feet4 ,! unit load+1 or weight p] squ>e foot w be3 #cccc_/ebc #f4cf p\nds4 ,! correct$ area includes ! ail]ons & ! "p ( ! l[] w+ occupi$ by ! body4 99,empirical ,=mula = ,load+994 ,aft] inve/igat+ a l>ge numb] ( practical biplanes1 ! au?or has develop$ an expression = det]m9+ ! approximate unit load+4 ,:5 ?is is f\nd1 ! approximate area c be f\nd by divid+ ! total weight by ! unit load+4 ,?is gives an idea z to ! area us$ 9 practice4 ,x 0 f\nd t ! unit load+ increas$ ) ! velocity at ne>ly a uni=m rate4 ,?is gave an av]age /raight l9e =mula t agre$ v closely ) #abh examples4 ,if ,v ,maximum velocity 9 miles p] h\r1 & w weight p] squ>e foot1 !n ! unit load+ becomes3 w #j4jfe,v - #j4be = ! av]age case4 ,= high spe$ sc\ts ?is gives a result t is a trifle l[1 ! =mula = a fa/ ma*9e be+ m ne>ly w #j4fe,v - #j4ae1 = spe$s ov] #ajj miles p] h\r4 ,a two-seat ma*9e ( av]age size weighs #bejj p\nds1 & has a maximum spe$ ( #ij miles p] h\r4 ,f9d ! approximate unit load+ & area4 ,! load+ becomes3 w #j4jfe,v - #j4be 7#j4jfe x #ij7 - #j4be #e4f p\nds p] squ>e foot4 ,! approximate area w be3 #bejj_/e4fj #ddf squ>e feet4 ,if ! above ma*9e _h a spe$ ( #aaj miles p] h\r1 ! =mula w\ld be *ang$ = ! high-spe$ type ma*9e1 & ! load+ w\ld become3 w #j4jfe,v - #j4ae 7#j4jfe x #aaj7 - #j4ae #g4jj p\nds p] squ>e foot4 ,! requir$ area w be3 #bejj_/g4j #cgb squ>e feet4 ,:5 ! unit load is also det]m9$ 9 ?is way x is a v simple matt] to *oose ! w+ section f ,ky w_/,v4 99,area ,f ,live ,load & ,spe$994 ,by a comb9ation ( empirical =mula we c approximate ! area directly4 ,= ! av]age size ma*9e1 w #j4jfe,v - #j4be4 ,& ! total weight ,w ,u_/#j4cb :]e ,u is ! useful or live load4 ,s9ce ,a ,w_/w1 !n ,a ,u_/7#j4fe,v - #j4be7 x #j4cb ,u_/#j4jba,v - #j4jh4 ,?us if an a]oplane travels at #ij miles p] h\r & has c>ri$ a useful load ( #hjj p\nds 7includ+ gas & oil71 ! approximate area is3 ,a ,u_/#j4jba4,v #j4jh #hjj_/7j4jba x #ij7 - #j4jh #ddb squ>e feet4 ,?is assumes t ! useful load is #j4cb ( ! total load & t ! spe$ is less ?an #ajj miles p] h\r4 ,,*apt] ,,xv4 ,,balance ,,& ,,/ability4 99,elem5ts ( ,/ability994 ,:5 we balance a bo>d on a fulcrum s t x /&s 9 a p]fectly horizontal position1 ! bo>d is said to be ,9 equilibrium1 or is support$ at its ,c5t] ( gravity4 ,!re is only "o po9t at :i* a body w balance1 & ?is po9t is at ! c5t] ( gravity or ,c4 ,g4 ,9 an a]oplane1 ! comb9$ mass ( ! body1 motor1 w+s1 fuel1 *assis1 tail & live load has a c5t] ( gravity or a balanc+ po9t at :i* ! lift mu/ be appli$ if ! ma*9e is to re/ 9 equilibrium4 ,:5 ! c5t] ( lift 7or c5t] ( pressure7 does n pass ?r\gh ! c5t] ( gravity ( ! a]oplane1 "s o!r =ce mu/ be appli$ to ov]come ! unbalanc$ condition4 ,:5 ! ma*9e is unbalanc$ 9 a =e & aft direction ) ! tail l[1 a =ce mu/ be appli$ by ! elevator flaps t is opposite & equal to ! mom5t ( ! unbalanc$ =ces4 ,an a]oplane is /able :5 x is balanc$ 9 su* a way t x returns to a /ate ( equilibrium aft] meet+ ) a di/urbance4 ,:5 di/urb$1 a /able body does n usually return in/antly to its position ( equilibrium1 b rea*es x aft] a s]ies ( decreas+ oscillations4 ,! heavi] ! body1 & ! m compact its =m1 ! long] w x oscillate ab\t its fulcrum be=e com+ to re/4 ,by arrang+ broad surfaces at ! ends ( ! oscillat+ body1 a portion ( ! en]gy w be exp5d$ 9 creat+ air curr5ts1 & ! motion w be readily damp$ out4 ,if ! damp+ effect is s great t ! body does n sw+ back aft] once rea*+ ! position ( equilibrium1 ! body is said to be dead beat1 or dynamically /able4 ,!re is a great diff]5ce betwe5 ! /atic =ces t t5d to return ! body to a position ( equilibrium & ! dynamic ret>d+ =ces t t5d to damp out ! oscillations4 ,usually1 a body ) excessive /atic /ability is f> f be+ /able 9 a true s5se1 s9ce su* a body t5ds to oscillate long]1 & m viol5tly1 ?an "o 9 :i* ! /atic re/or+ =ces are n s /rongly m>k$4 ,a body may be /atically b n dynamically /able1 b a dynamically /able body mu/ ( necessity be /atically /able4 ,/atic /ability 9 calm air is det]m9$ by ! location ( ! c5t] ( gravity1 ! c5t] ( lift1 ! c5t] ( propell] ?ru/1 ! c5t] ( area ( ! surfaces1 & ! c5t] ( ! =w>d resi/ance4 ,! =ces act+ ?r\gh ^! c5t]s are3 7#a7 ,! weight2 7#b7 ,! lift+ =ce2 7#c7 ,! propell] ?ru/2 7#d7 ,! resi/ance4 ,! weight & lift are v]tical =ces equal & opposite 9 direction4 ,! ?ru/ & resi/ance are horizontal =ces1 also equal & opposite 9 direction4 ,:5 all ( ^! =ces int]sect at a common po9t1 !y w completely neutralize "o ano!r & ! body w be 9 equilibrium4 ,dynamic /ability is atta9$ by ! use ( l>ge damp+ surfaces su* z ! /abiliz] surface1 f9s1 & ! elevator4 ,^! act to kill ! oscillations set up by ! /atic right+ c\ples or =ces4 ,)\t suitable damp+ surfaces ! ma*9e w\ld soon be out ( control 9 gu/y wea!r s9ce successive w9d gu/s w act to increase ! oscillations ( ! right+ =ces until ! ma*9e w turn completely ov]4 ,on ! o!r h&1 an a]oplane c be too /able & !re=e difficult to /e] or control 9 gu/s because ( its t5d5cy t[>d *ang+ its attitude ) e gu/ 9 ord] to re/ore its equilibrium4 ,a ma*9e %\ld only be p>tially /able1 & ! majority ( pilots are firmly set aga9/ any =m ( me*anical or inh]5t control4 ,no matt] h[ simple ! me?od1 me*anical control always introduces a c]ta9 am\nt ( me*anism t may g wrong4 ,! "q ( /ability has already be5 solv$ to a suffici5t ext5t4 ,a di/urbance t simply *anges ! direction ( travel is n consid]$ an un/able =ce s9ce x normally does n t5d to endang] ! ma*9e4 ,ne>ly any ma*9e1 equipp$ ) any possible =m ( control app>atus1 t5ds to *ange its direction :5 be+ right$4 99,axes ( ,/ability994 ,an a]oplane has six degrees ( fre$om or motion4 ,?ree are ( translation or /raight l9e motion1 & ?ree are ( rotation ab\t rectangul> axes4 ,x c travel =w>d 9 a /raight l9e1 rise & fall 9 a v]tical plane1 or skid sidewise4 ,:5 x rolls f side to side ab\t ! =e & aft axis 7,x axis7 x is lat]ally un/able4 ,:5 pit*+ up & d[n 9 a =e & aft direction1 & ar\nd an axis p>allel ) ! l5g? ( ! w+s 7,y axis71 ! ma*9e is said to be longitud9ally un/able4 ,:5 sw++ or ,yaw+ f "r to left ab\t a v]tical axis 7,z axis7 x is un/able 9 ,yaw4 ,roll+ is resi/$ by ! ail]ons1 pit*+ by ! elevators & /abiliz]1 & yaw+ by ! v]tical directional rudd]4 ,lat]al oscillation are damp$ out by ! w+ surfaces & by v]tical surfaces or ,f9s4 ,longitud9al oscillations are damp$ mo/ly by ! /abiliz] & elevator surfaces4 ,directional or yaw+ vibrations are correct$ by ! damp+ action ( ! v]tical tail f91 v]tical rudd] & ! sides ( ! body1 ! latt] also s]v+ to damp out longitud9al vibrations4 ,on an absolutely calm day1 ! pilot c %ut (f ! motor & glide d[n )\t t\*+ ! controls if ! ma*9e is longitud9ally /able4 ,! glide g5]ally />ts ) a few pit*+ oscillations1 b ^! gradually are damp$ out by ! tail z soon z ! ma*9e picks up its natural glid+ angle & spe$1 & f ?is po9t x w cont9ue )\t oscillat+4 99,! ,spiral & ,nose ,dive994 ,!re are two =ms ( in/ability t h n yet be5 fully correct$1 & bo? are highly dang]\s4 ,"o ( ^! is kn[n z ! spiral dive or nose sp91 & ! o!r z ! /raight nose dive4 ,! a]oplane 9 a spiral nose dive rotates rapidly ab\t a v]tical axis dur+ ! dive4 ,spiral in/ability result+ f lat]al in/ability1 c be m9imiz$ by decreas+ ! area ( ! v]tical rudd] & by ! prop] plac+ ( f9s s t !re is n s great an excess ( v]tical area to ! re> ( ! ,c4 ,g4 ,! cov]$-9 body acts z a f9 & w be productive ( spiral in/ability if ! area is n prop]ly di/ribut$4 ,9 ! majority ( cases ! re> ( ! body is equival5t to a l>ge f9 plac$ to ! re> ( ! ,c4 ,g4 ,a f9 above ! ,g4 ,g4 t5ds to r$uce all spirall+4 99,/ability & ,spe$994 ,an a]oplane 9 /raight horizontal flight mu/ be driv5 at su* an angle1 & su* a spe$1 t ! weight is j su/a9$4 ,to be inh]5tly /able ! ma*9e mu/ always t5d to increase its spe$ by div+ %\ld ! p[] be cut (f 9 any way4 ,an a]oplane t does n t5d to increase its spe$ 9 ?is way1 ,/alls or becomes out ( control4 ,any ma*9e t w automatically pick up its glid+ angle aft] ! propell] ?ru/ has ceas$ is at lea/ p>tially inh]5tly /able1 & if x does n possess ?is degree ( /ability1 o!r =ms ( /ability are practically wor?less4 ,! ma*9e hav+ ! smalle/1 flatte/ glid+ angle is naturally safe/ 9 cases ( p[] failure1 & h5ce ! glid+ angle is some:at relat$ to ! subject ( /ability4 ,illu/ration3 ,a ,spani% ,a]oplane ,us+ a ,peculi> ,=m ( ,upp] ,f94 ,^! ,f9s ,also ,p]=m ! ,duty ( ,v]tical ,rudd]s z ,well z ,act+ z ,/abiliz]s4 ,! longitud9al /ability decreases ) a decrease 9 ! spe$1 ! =e & aft vibrations becom+ m rapid due to ! decreas$ effect ( ! tail surfaces1 & to ! r$uction ( w+ lift4 ,in/ability at l[ spe$s is common to all a]oplanes1 :e!r inh]5tly /able or n1 & at a c]ta9 critical spe$ ! ma*9e becomes absolutely un/able 9 a dynamic s5se4 ,if a ma*9e is to be /able at l[ spe$s1 x mu/ n fly at too great an angle ( incid5ce at ^! spe$s1 & x %\ld h a v l>ge tail surface act+ at a consid]able di/ance f ! w+s4 ,hunsak] /ates t ! l[e/ spe$ %\ld n require m ?an #hj p] c5t ( ! total lift possible4 99,in]tia or ,fly:eel ,effect994 ,! pr9cipal weights %\ld be conc5trat$ z ne>ly z possible at ! c5t] ( gravity4 ,weights plac$ at extreme out] positions1 z at ! w+ tips1 or f> ahead ( ! w+s1 t5d to ma9ta9 oscillations by virtue ( _! fly:eel effect4 ,! measure ( ?is in]tia or fly:eelage is kn[n z ! ,mom5t ( ,in]tia & is ! sum ( ! products ( all ! masses by ! squ>es ( _! di/ances f ! c5t] ( gravity4 ,a great am\nt ( in]tia mu/ be met by a l>ge damp+ surface or control area if ! vibrations are to be damp$ out 9 a giv5 "t4 ,9 tw9-motor$ a]oplanes ! motors %\ld be kept z close to ! body z ! propell]s w p]mit4 99,w9d ,gu/s & ,spe$994 ,a ma*9e fly+ at high spe$ is less affect$ by w9d gu/s or v>iations 9 d5sity ?an a sl[ ma*9e1 s9ce ! di/urb+ curr5ts are a small] p]c5tage ( ! total spe$4 ,9 addition1 a high spe$ results 9 small] /resses due to ! gu/s4 99,gyroscopic ,in/ability994 ,! motor gyroscopic =ces d n affect ! /ability ( a ma*9e to any great ext5t1 & 9 tw9 motor$ a]oplanes ! gyroscopic action ( ! propell]s is almo/ entirely neutraliz$4 ,at "o "t ! gyroscopic torque 0 blam$ = e =m ( in/ability1 b on inve/igation x 0 f\nd t ! practical effect 0 negligible4 99,in/ability ,due ,p[] ,plant994 ,! p[] plant affects /ability 9 a numb] ( ways4 ,! ?ru/ ( ! propell] may cause a =e & aft mom5t if ! c5t] l9e ( ?ru/ does n pass ?r\gh ! c5t] ( resi/ance4 ,?is causes ! ma*9e to be held head up1 or head d[n1 accord+ to :e!r ! l9e ( ?ru/ is bel[ or above ! ,c4 ,g4 ,if ! propell] ?ru/ t5ds to hold ! head up 9 normal flight1 ! ma*9e w t5d to dive1 & assume its normal glid+ velocity ) ! p[] (f1 h5ce ?is is a condition ( /ability4 ,) ! effect ( ! ?ru/ neutral1 or ) ! ?ru/ pass+ ?r\gh ! c5t] ( resi/ance1 ! ma*9e w n t5d to ma9ta9 ! spe$1 & h5ce x is likely to /all unless imm$iately correct$ by ! pilot4 ,) ! l9e ( ?ru/ above ! ,c4 ,g41 ! /all effect is /ill fur!r increas$ s9ce ) ?is arrangem5t !re is a v decid$ t5d5cy = ! ma*9e to nose up & increase ! angle ( incid5ce :5 ! p[] is cut (f4 ,illu/ration3 ,/eel ,elevator & ,rudd] ,con/ruction ,us$ on a ,european ,ma*9e4 ,! ,elevators ,also ,act z ,/abiliz]s1 ! ,entire ,surface ,turn+ ,ab\t ! ,tube ,sp>4 ,! slip /ream ( ! propell] has a v decid$ effect on ! tail surfaces1 ^! be+ mu* m effective :5 ! propell] slip /ream passes ov] !m4 ,) lift+ tails1 or tails t normally c>ry a "p ( ! load1 ! /oppage ( ! slip /ream decreases ! lift ( ! tail & consequ5tly t5ds to /all ! ma*9e4 ,non-lift+ tails %\ld be arrang$ s t ! slip /ream /rikes d[n on ! upp] surface4 ,?is t5ds to =ce ! tail d[n1 & ! head up 9 normal flight1 & :5 ! p[] ceases ! tail w be reliev$ & !re w be an automatic t5d5cy t[>d div+ & increase 9 spe$4 ,on a tw9 a]oplane1 a simil> effect is obta9$ by mak+ ! upp] tips ( bo? propell]s turn inw>dly4 ,! air is ?us ?r[n d[n on ! tail4 ,) a s+le motor1 ! torque t5ds to turn ! a]oplane 9 a direction opposite to ! rotation ( ! propell]4 ,lat]al /ability is ?us int]f]$ ) :5 ! motor is cut (f or r$uc$ 9 spe$4 ,) "r-h& propell] rotation1 = example1 ! ma*9e w be turn$ t[>d ! left1 =c+ ! left tip d[n4 ,to ma9ta9 a horizontal attitude1 ! left ail]on mu/ be held d[n by an am\nt j suffici5t to ov]come ! torque4 ,9 "s ma*9es "o w+ tip is giv5 a p]man5t increase 9 incid5ce s t ! d[n seek+ tip is giv5 p]man5t additional lift4 99,lat]al ,/ability994 ,:5 an a]oplane is turn$ %>ply 9 a horizontal plane1 or ,yaws1 ! out] & fa/] mov+ w+ tip receives ! great] lift1 & a lat]al roll+ mom5t is produc$ ab\t ! =e & aft axis4 ,9 ! opposite condition1 a lat]al roll+ mom5t t5ds to yaw or to ?r[ ! a]oplane (f a /raight c\rse4 ,bel[ a c]ta9 critical spe$1 ! lat]al or roll+ oscillations increase 9 amplitude1 ) a /rong t5d5cy to side slip1 skid or spiral4 ,! tail f9 or rudd] ret>ds ! tail velocity 9 a side slip1 & ?us turns ! slipp+ or skidd+ ma*9e into a v]tical spiral or sp9n+ nose dive4 ,?is sp9 increases ! angle ( bank & h5ce ! side slip4 ,?is 9 turn increases ! turn+ or yaw+ velocity1 & ! spiral />ts4 ,?is t5d5cy t[>d a spiral dive c be correct$ by a v]tical f9 plac$ =w>d1 & above ! c5t] ( gravity1 or by rais+ ! w+ tips4 ,an upp] f9 ( ?is type w give a =ce t t5ds to break up ! bank :5 side slip />ts & ?us w prev5t sp9n+4 ,illu/ration3 ,sp]ry ,gyroscopic ,control ,sy/em = ,automatic ,/ability4 ,! ,gyroscopic ,control at ! ,left ,controls ! ,movem5ts ( ! ,electric ,s]vo-,motor at ! ,extreme ,"r4 ,?is ,motor ,op]ates ! ,control ,surfaces ,?r\gh ! ,pulley ,%[n4 ,a ,small ,electric ,g5]ator ,betwe5 ! ,s]vo-,motor & ,gyroscope ,provides ! ,curr5t & ,is ,driv5 by a ,small ,w9d ,propell]4 ,at normal spe$s ! roll+ is damp$ d[n by ! w+ surfaces1 & c be fur!r controll$ by ! application ( ! ail]ons4 ,at ! l[] critical spe$ :5 ! ma*9e is /all$1 "o w+ tip has no m lift ?an ! o!r1 & h5ce ! damp+ effect ( ! w+s & ! action ( ! ail]ons becomes negligible4 99,dut* ,roll994 ,9 ,dut* ,roll1 ! roll+ is accompani$ by an alt]nate yaw+ f "r to left4 ,?is is aggravat$ by a f9 plac$ high above ! ,c4 ,g41 & h5ce corrections = spiral dive conflict ) corrections = ,dut* roll4 ,! roll+ is accompani$ by "s side slip1 & ! motion is /able provid+ t !re is suffici5t f9 9 ! re> & n an excessive am\nt above ! ,c4 ,g4 99,degree ( ,/ability994 ,excessive /ability is dang]\s unless ! control surfaces are p[]ful en\gh to ov]come ! /able t5d5cy4 ,s9ce a /able ma*9e always seeks to face ! relative w9d1 x becomes difficult to h&le 9 gu/y wea!r1 z x is cont9ually *ang+ its c\rse to meet p]iodic di/urbances4 ,?is is aggravat$ by a high degree ( /atic /ability1 & may be positively dang]\s :5 l&+ 9 w9dy wea!r4 99,control ,surfaces994 ,a non-lift+ tail mu/ give no lift :5 at a z]o angle ( incid5ce4 ,x mu/ be symmetrical 9 section s t equal values ( lift are giv5 by equal positive & negative angles ( incid5ce4 ,squ>e edg$1 flat surfaces are n desirable because ( _! great resi/ance4 ,a d\ble camb]$ surface is suitable = su* controls z ! /abiliz]1 elevator & rudd]4 ,x has a l[ resi/ance1 p]mits ( /rong int]nal sp>s1 & is symmetrical ab\t ! l9e ( ! *ord4 ,"s tails are provid$ ) a camb]$ top & a flat bottom surface s t ! d[n wa% ( ! w+s is neutraliz$4 ,"u ord9>y conditions ?is w\ld be an unsymmetrical lift+ surface1 b :5 prop]ly adapt$ to ! w+s ! lift+ effect is completely neutraliz$ by ! d[n wa%4 ,! curvature ( ! section %\ld be su* t ! movem5t ( ! c5t] ( pressure is z small z possible4 ,) a small movem5t ( ! c5t] ( pressure1 ! surface c be accurately balanc$ & h+$ on ! c5t] ( pressure l9e4 ,x is desirable to h ! maximum ?ickness ( section at1 or ne> to ! ,c4 ,p41 s t a deep sp> c be us$ = ! support ( ! h+e sy/em4 ,usually ! movem5t ( ! control surfaces is limit$ to an angle ( #cj degrees on ei!r side ( ! c5t] l9e1 z ! lift ( all surfaces />t to decrease aft] ?is po9t is rea*$4 ,! surface movem5t %\ld be limit$ by ! maximum lift angle ( ! section 9 any case1 s9ce an accid5t w be b\nd to occur if !y are all[$ movem5t beyond ! angle ( maximum lift4 ,9 locat+ ! control surfaces1 c>eful att5tion %\ld be paid to ! surr\nd+ air conditions s t !y w n be unduly affect$ by ! wa%-d[n ( ! w+s or body4 ,! effectiv5ess ( ! tail surfaces is v mu* r$uc$ by br++ !m close to ! w+s1 & ! lift is always r$uc$ by ! wa% ( a cov]$ fuselage4 ,! wa%-d[n effect ( ! w+s on ! tail is proportional to ! *ord & n to ! span1 & = ?is reason an increase 9 span does n always necessitate an increase 9 ! l5g? ( ! body4 ,an adequate damp+ effect requires a l>ge surface at ! end ( a long lev] arm4 99,balanc+ ! ,a]oplane994 ,figs4 #a to #f %[ ! pr9ciples involv$ 9 ! balanc+ ( ! a]oplane4 ,9 ,fig4 #a a numb] ( weights #a'-b'-c' & #e,m are support$ on a beam1 ! load be+ balanc$ on ! fulcrum po9t ,m4 ,! load #b' be+ directly ov] ! fulcrum1 has no influ5ce on ! balance1 b load #a' at ! left t5ds to turn ! mass 9 a left-h& direction1 :ile #c' & #e,m t5d to give x a "r-h& rotation4 ,?is turn+ t5d5cy dep5ds ^u ! weights ( ! bodies & _! di/ance f ! fulcrum4 ,! turn+ t5d5cy or ,mom5t is measur$ by ! product ( ! weight & ! di/ance f ! fulcrum4 ,if weight #a' %\ld be #aj p\nds1 & its di/ance ,a' f ! fulcrum %\ld be #bj in*es1 !n x w\ld cause a left-h& mom5t ( #aj x #bj #bjj in* p\nds4 ,if ! sy/em is to be 9 balance1 !n ! left-h& mom5t ( #a' %\ld be equal to ! sum ( ! mom5ts ( #c' & #e,m4 ,?us3 #a' x ,a 7#c' x ,b7 7#e,m x ,c'74 ,illu/ration3 ,figs4 #a-f4 ,me?ods ( ,balanc+ an ,a]oplane ,ab\t ,c5t] ( ,lift4 ,! application ( ?is pr9ciple z appli$ to a monoplane is %[n by ,fig4 #d1 9 :i* ,x-,x is ! c5t] ( pressure or lift4 ,! c5t] ( lift corresponds to ! fulcrum 9 ,fig4 #a1 & ! weights ( ! a]oplane masses & _! di/ance f ! c5t] ( lift are %[n by ! same lett] z 9 ,fig4 #a4 ,! eng9e #a' is at ! "r ( ! ,c4 ,p4 by ! di/ance ,a1 :ile ! fuel tank #b is plac$ on ! ,c4 ,p4 9 ! same way t ! weight #b' 9 ,fig4 #a is plac$ directly ov] ! fulcrum4 ,by plac+ ! tank 9 ?is position1 ! balance is n affect$ by ! empty+ ( ! fuel s9ce x ex]ts no mom5t4 ,! *assis ,g act+ ?r\gh ! di/ance ,e is 9 ! same direction z ! eng9e load4 ,! body #e ) its c5t] ( gravity at ,m acts ?r\gh ! di/ance ,c1 :ile ! weight ( ! pilot #c ex]ts a "r-h& mom5t ) ! lev] arm l5g? ,b4 ,if ! mom5ts ( all ^! weights are n 9 equilibrium1 an additional =ce mu/ be ex]t$ by ! tail ,v4 ,fig4 #b %[s an additional weight #d' t corresponds to ! weight ( ! pass5g] #d 9 ,fig4 #e4 ,?is t5ds to increase ! "r turn+ mom5t unless ! fulcrum is mov$ t[>d ! new load4 ,9 ,fig4 #b ! fulcrum ,m rema9s at ! same po9t z 9 ,fig4 #a1 h5ce ! sy/em requires a new =ce ,p' act+ up at ! end ( ! beam4 ,if ! load 0 9 equilibrium be=e ! addition ( #d'1 !n ! =ce ,p' mu/ be su* t ,p' x ,t' #d x ,d'4 ,9 ! equival5t ,fig4 #e1 ! c5t] ( gravity has mov$ f its =m] position at ,s to ! new position at ,r1 ! ext5t ( ! motion be+ indicat$ by ,u4 ,to hold ?is 9 equilibrium1 an upw>d =ce ,p mu/ be ex]t$ by ! elevator at ,y1 ! lev] arm be+ equal to 7,t ,u74 ,fig4 #f %[s ! s+le-seat]1 b "u a new condition1 ! c5t] ( pressure hav+ mov$ back f ,x-,x to ,z4 ,to hold ! a]oplane 9 equilibrium1 a d[nw>d =ce mu/ be provid$ by ! tail ,v :i* w cause a "r-h& mom5t equal to ! product ( ! entire weight & ! di/ance ,u4 ,= e %ift 9 ! c5t] ( pressure1 !re mu/ be a correspond+ mom5t provid$ by ! elevator surface4 ,! condition is %[n by ! simple load$ beam ( ,fig4 #c4 ,9 ?is case ! fulcrum has be5 mov$ f ,m to ,n1 a di/ance equal to ! c5t] ( pressure movem5t 9 ,fig4 #f4 ,?is requires a d[nw>d =ce ,p' to ma9ta9 equilibrium4 99,c5t] ( ,pressure ,calculation994 ,fig4 #g is a diagram %[+ ! me?od ( calculat+ ! c5t] ( gravity4 ,! ref]5ce l9e ,r is %[n bel[ ! elevators & is drawn p>allel to ! c5t] ( pressure l9e ,w-,w1 ! latt] l9e be+ assum$ to pass ?r\gh ! c5t] ( gravity4 ,! l9e ,r may be locat$ at any conv5i5t po9t1 z at ! propell] flange or else:]e1 b = cle>ness 9 illu/ration x is locat$ to ! re> ( ! a]oplane4 ,! weight ( ea* item is multipli$ by ! di/ance ( its c5t] ( gravity f ! l9e ,r1 ^! products are add$1 & ! sum is !n divid$ by ! total weight ( ! ma*9e4 ,! result ( ?is division gives ! di/ance ( ! c5t] ( gravity f ! l9e ,r4 ,?us1 if ! c5t] ( gravity ( ! body 7#aa7 is locat$ at 7#aj71 !n ! product ( ! body weight multipli$ by ! di/ance ,b w give ! mom5t ( ! body ab\t ! l9e ,r4 ,! weight ( ! motor 7#b7 multipli$ by ! di/ance ,f gives ! mom5t ( ! motor ab\t ,r1 & s on ?r\gh ! li/ ( items4 ,illu/ration3 ,c5t] ,( ,gravity ,table ,! di/ance ( ! c5t] ( gravity 7or c5t] ( pressure7 f ! ref]5ce l9e ,r is giv5 by ,h ,k4 ,?is gives ! num]ical value #baicej_/acge #aeif in*es4 ,?us if we measure #aei4f in*es f ,r t[>d ! w+s we w h locat$ ! c5t] ( gravity4 ,! location ( ! ,c4 ,g4 c be *ang$ by %ift+ ! weights ( ! motor1 pass5g]1 or o!r easily mov$ items4 ,9 any case1 ! ,c4 ,g4 %\ld lie ne> ! c5t] ( pressure4 99,tail ,lev] ,arms994 ,! effective damp+ mom5t ex]t$ by ! fix$ /abiliz] surface 7#ab7 w be ! product ( its area by ! di/ance 7,i71 measur$ f ! c5t] ( pressure ( ! w+ to ! c5t] ( pressure ( ! /abiliz]4 ,! lev] arm ( ! elevator is ! di/ance 7,h7 measur$ f ! c5t]s ( pressure z be=e4 ,illu/ration3 ,fig4 #g4 ,me?od ( ,det]m9+ ! ,c5t] ( ,gravity ( an ,a]oplane4 99,resultant ,=ces & ,mom5ts 9 ,flight994 ,! a]oplane is 9 equilibrium :5 all ( ! =ces pass ?r\gh a common c5t]1 z %[n by ,fig4 #h4 ,9 ?is figure ! lift 7,l71 ! weight 7,w71 ! l9e ( propell] ?ru/ 7,t71 & ! resi/ance 7,r7 all pass ?r\gh ! c5t] ( gravity %[n by ! black dot ,c4 ,g4 ,!re are no mom5ts & h5ce no correction is ne$$ f ! elevator 7,t74 ,9 ,fig4 #i1 ! ?ru/ & resi/ance pass ?r\gh ! c5t] ( gravity z be=e1 b ! c5t] ( lift 7,l7 does n pass ?r\gh ! c5t] ( gravity1 ! di/ance betwe5 ! two be+ indicat$ by 7n74 ,?is causes a mom5t1 ! l5g? ( ! lev] arm 7n7 be+ effective 9 giv+ a "r-h& rotation to ! body4 ,if horizontal flight is to be _h ?is mu/ be resi/$ by ! upw>d elevator =ce 7,e74 ,9 ,fig4 #aj1 ! lift passes ?r\gh ! c5t] ( gravity1 b ! l9e ( resi/ance lies bel[ x by ! am\nt 7m74 ,! ?ru/ 7,t7 t5ds to rotate ! ma*9e 9 a left-h&$ direction4 ,! elevator mu/ ex]t a d[nw>d =ce 7e7 to resi/ ! mom5t caus$ by 7m74 ,?is is a bad disposition ( =ces1 z ! ma*9e w\ld t5d to /all or tail-dive %\ld ! propell] ?ru/ cease = ev5 an in/ant4 ,! /ability ( ,figs4 #h & #i w\ld n be affect$ by ! propell] ?ru/1 z x passes ?r\gh ! ,c4 ,g4 9 bo? cases4 ,9 ,fig4 #aa1 ! c5t] l9e ( ?ru/ is bel[ ! l9e ( resi/ance 7,r71 s t ! ?ru/ t5ds to hold ! nose up4 ,%\ld ! motor fail 9 ?is case1 ! nose w\ld drop & ! ma*9e w\ld />t on its glid+ angle & pick up spe$4 ,9 ,fig4 #ab none ( ! =ces int]sect at a common po9t1 ! lift & weight =m+ a "r-h&$ c\ple1 :ile ! ?ru/ 7,t7 & ! resi/ance 7,r7 =m a left-h&$ c\ple t opposes ! c\ple set up by ! weight & lift =ces4 ,if ! ?ru/-resi/ance c\ple c be made equal to ! lift-weight c\ple1 ! a]oplane w be 9 equilibrium & w ne$ no assi/ance f ! elevator4 ,z ! weights 9 ! a]oplane are all locat$ at diff]5t heights1 x is necess>y to obta9 ! c5t] ( gravity ( all ! loads 9 a v]tical plane z well z horizontally4 ,?us 9 ,fig4 #ac ! l9e ,c4 ,g4 is ! c5t] ( gravity ( ! eng9e weight 7#a71 ! w+ weight 7#b71 ! pilot's weight 7#c71 ! *assis weight 7#d71 ! fuselage weight 7#e71 & ! fuel tank weight 7#f74 ,! l9e ,c4 ,g4 is ! effective c5t] ( all ^! loads1 & is calculat$ by tak+ ! products ( ! weights by ! di/ance f a ref]5ce l9e su* z ,r-,r4 ,! c5t] ( resi/ance is ! effective c5t] ( all ! resi/ance produc+ items su* z ! w+s1 body1 /ruts1 *assis1 etc4 ,illu/ration3 ,figs4 #h-ae4 ,=ces ,affect+ ! ,longitud9al ,/ability ( an ,a]oplane4 ,a sugge/ion ( ! me?od employ$ 9 obta9+ ! c5t] ( resi/ance is %[n by ,fig4 #ad1 ! c5t] l9e ( resi/ance ,r-,r be+ ! resultant ( ! w+ resi/ance 7,d71 ! body resi/ance 7,b71 & ! *assis resi/ance 7,c74 ,x w be not$ t ! w+ resi/ance ( biplane w+s 7,w-,w'7 does n lay midway betwe5 ! w+s b r clos] to ! upp] w+1 z %[n by 7,e74 ,?is is due to ! upp] w+ p]=m+ ! great] "p ( ! lift4 ,9 locat+ ! c5t] ( resi/ance1 ! resi/ance =ces are treat$ exactly l ! weights 9 ! ,c4 ,g4 det]m9ation4 ,ea* =ce is multipli$ by its di/ance f a horizontal ref]5ce l9e1 & ! sum ( ! products is divid$ by ! total resi/ance4 ,z %[n1 ! c5t] ( resi/ance ,r-,r passes ?r\gh ! c5t] ( gravity ,c4 ,g4 ,! c5t] ( pressure l9e ,x-,x also conta9s ! c5t] ( resi/ance4 ,a /agg]$ biplane cell is %[n by ,fig4 #ae1 ! c5t] ( pressure ( ! upp] & l[] w+s be+ connect$ by ! l9e ,x-,x z be=e4 ,! c5t] ( resi/ance ( ! pair is %[n at 7,d71 :]e x is clos] to ! upp] w+ ?an to ! l[]4 ,a v]tical l9e ,y-,y dropp$ ?r\gh ! c5t] ( resi/ance gives ! location ( ! c5t] ( lift4 ,z %[n1 ! c5t] ( lift is br\ght =w>d by ! /agg] until x is a di/ance 7g7 9 front ( ! lead+ edge ( ! l[] w+4 ,! c5t] ( lift & ! c5t] ( resi/ance bo? lie on a l9e connect+ ! c5t] ( pressure ( ! upp] & l[] w+s4 99,calculation ( ,control ,surfaces994 ,x is almo/ impossible to give a h>d & fa/ rule = ! calculation ( ! control surfaces4 ,! area ( ! ail]ons & tail surfaces dep5ds ^u ! degree ( /ability ( ! ma9 w+s1 ^u ! mom5t ( in]tia ( ! complete ma*9e1 & ^u ! turn+ mom5ts4 ,if ! w+s are swept back or set ) a /agg]-decalage arrangem5t1 !y w require less tail ?an an or?ogonal cell4 ,all ( ^! quantities h to be work$ out diff]5tly = e individual case4 99,ail]on ,calculations994 ,! ail]ons may be us$ only on ! upp] w+ 7#b ail]ons71 or !y may be us$ on bo? ! upp] & l[] w+s4 ,:5 only two are us$ on ! upp] w+ x is usually ! practice to h consid]able ov]hang4 ,:5 ! w+s are ( equal l5g? ei!r two or f\r ail]ons may be us$4 ,r\ghly1 ! ail]ons are ab\t "o-qu>t] ( ! w+ span 9 l5g?4 ,) a long span1 a giv5 ail]on area w be m effective because ( its great] lev] arm4 ,if a area ( ail]ons1 & ,a total w+ area 9 squ>e feet1 ) ,s w+ span 9 feet1 ! ail]on area becomes3 a #c4b;,a_/,s4 ,x %\ld be borne 9 m9d t ?is applies only to an a]oplane hav+ two ail]ons on ! upp] w+1 s9ce a f\r-ail]on type usually has ab\t #ej p] c5t m ail]on area = ! same w+ area & w+ span4 ,=1 example1 let ! w+ span be #dj feet & ! area ( ! w+s be #ddj squ>e feet1 !n ! ail]on area w be3 a #c4b;,a_/,s #c4b x #ddj_/dj #ce4b squ>e feet4 ,if f\r ail]ons 7 employ$1 two on ! upp] & two on ! l[] w+1 ! area w\ld be increas$ to #a4e x #ce4b #eb4h squ>e feet4 ,z an example 9 ! sizes ( ail]ons1 ! foll[+ table w be ( int]e/3 ,illu/ration3 ,ail]on ,sizes ,table ,9 cases :]e ! upp] & l[] spans are n equal1 take ! av]age span--t is1 "o-half ! sum ( ! two spans4 99,/abiliz] & ,elevator ,calculations994 ,^! surfaces %\ld prop]ly be calculat$ f ! values ( ! upsett+ c\ples & mom5ts ( in]tia1 b a r\gh rule c be giv5 t w approximate ! area4 ,if a' comb9$ area ( /abiliz] & elevator 9 squ>e feet2 ,l di/ance f ,c4 ,p4 ( w+s to ! ,c4 ,p4 ( tail surface2 ,a ,area ( w+s 9 squ>e feet1 & ,c *ord ( w+s 9 feet1 !n3 a' #j4ea;,,ac_/,l4 ,assum+ our area z #dcj squ>e feet1 ! *ord z #e4g feet1 & ! lev] arm z #bj feet1 !n3 a' #j4ea;,,ac_/,l #j4ea x #dcj x #e4g_/bj #fb4e squ>e feet1 ! comb9$ area ( ! elevators & /abiliz]4 ,! relation betwe5 ! elevator & /abiliz] areas is n a fix$ quantity1 b ma*9es hav+ a /abiliz] ab\t #bj p] c5t great] ?an ! elevator give good results4 ,9 ! example j giv51 ! elevator area w be3 #fb4e_/bb #bh4da squ>e feet1 :]e #b4b is ! con/ant obta9$ f ! ratio ( sizes4 ,! area ( ! /abiliz] is obta9$ f3 #bh4da x #a4b #cd4a squ>e feet4 99,negative ,/abiliz]s994 ,a consid]able am\nt ( inh]5t longitud9al /ability is obta9$ by plac+ ! /abiliz+ surface at a slight negative angle ) ! w+s4 ,?is angle g5]ally v>ies f -#b to -#f4 ,at small angles ( w+ incid5ce ! negative angle ( ! tail w be at a maximum1 & act+ d[n w oppose fur!r div+ & t5d to head ! ma*9e up4 ,at l>ge w+ angles1 ! tail w be depress$ s f> t ! tail angle w become positive in/ead ( negative1 & ?us ! lift on ! tail w oppose ! w+s & w =ce ! ma*9e to a small] angle ( incid5ce4 ,! negative angle c ?us be adju/$ to give longitud9al /ability )9 ! ord9>y range ( flight angles4 99,/abiliz] ,%apes & ,aspect ,ratio994 ,/abiliz]s h be5 built 9 a great numb] ( diff]5t %apes1 semicircul>1 triangul>1 elliptical1 & ( rectangul> w+ =m4 ,measur$ at ! re> h+$ jo9t1 ! span or wid? ( ! /abiliz] is ab\t #a_/c ! w+ span = spe$ sc\ts1 & ab\t #a_/d ! w+ span = ! l>g] ma*9es4 ,ne>ly all mod]n ma*9es h non-lift+ tails1 or tails s modifi$ t !y are ne>ly non-lift+4 ,s9ce flat plates give ! greate/ lift ) a small aspect ratio1 & h5ce are mo/ effective :5 runn+ ov] ! gr\nd at l[ spe$s1 ! /abiliz]s & elevators are ( comp>atively l[ aspect4 ,9 g5]al1 an aspect ratio ( #c is a good value = ! /abiliz]4 ,v]tical rudd]s g5]ally h an aspect ratio ( #a1 & h5ce are ev5 m effective p] unit area ?an ! /abiliz]s4 ,?is is p>ticul>ly necess>y 9 gr\nd runn+4 ,illu/ration3 ,ail]on ,control ,diagram ( ,curtiss ,,jn#d-;,b4 ,illu/ration3 ,elevator ,control ,diagram ( ,curtiss ,,jn#d-;,b4 99,v]tical ,rudd]s994 ,! calculation ( ! v]tical rudd]s mu/ take ! mom5t ( in]tia & yaw+ mom5ts into effect1 & ?is is r a complicat$ calculation = ! beg9n]4 ,z an approximation1 ! area ( ! rudd] c be tak5 f #i to #ab squ>e feet = ma*9es ( ab\t #dj feet span1 & f #e to #h squ>e feet = spe$ sc\ts4 ,illu/ration3 ,/ick ,control ,us$ on ! ,caudron ,biplane4 ,w+ ,w>p ,is ,us$ ,in/ead ( ,ail]ons4 ,back & ,=? ,movem5t ,actuates ,elevator4 ,illu/ration3 ,g]man ,/ick ,control ,) ,d\ble ,grips4 ,a4 ,lat* on ! ,side ( ! ,/ick ,acts on a ,sector ,s ,t ! ,lev] ,c ,be ,held at ,any ,po9t4 ,x ,is ,releas$ by ! ,pressure ( ! ,knees4 99,w+ ,/ability994 ,"u w+ sections1 ! subject ( ! c5t] ( pressure movem5t has already be5 dealt )4 ,! v>iation ( ! c5t] ( pressure ) ! angle ( incid5ce t5ds to de/roy longitud9al /ability s9ce ! c5t] ( pressure does n at all times pass ?r\gh ! c5t] ( gravity4 ,on "s w+s1 ! camb] is su* t ! v>iation 9 ! position ( ! c5t] ( pressure is v little1 & h5ce ^! are kn[n z /able w+s4 ,a reflex curve 9 ! trail+ edge ( a w+ r$uces ! c5t] ( pressure movem5t1 & swept back w+s are also us$ z an aid 9 secur+ longitud9al /ability4 ,introduc+ /agg] & decalage into a biplane pair c be made to produce almo/ p]fect /atic longitud9al /ability4 ,x %\ld be not$ t /ability obta9$ by w+ & camb] arrangem5ts is /atic only1 & requires damp+ surfaces to obta9 dynamic /ability4 ,illu/ration3 ,=m ( ,control ,us$ on ! ,nieuport ,monoplane4 99,manual ,controls994 ,9 flight1 ! aviator has ?ree control surfaces to op]ate1 ! ail]ons1 elevator1 & rudd]4 ,9 ! usual =m ( ma*9e ! ail]ons & elevator are op]at$ by a s+le lev] or control column1 :ile ! rudd] is connect$ ) a foot b>4 ,9 ! small] ma*9es ,/ick ,control is g5]ally us$1 ! ail]ons & elevator be+ mov$ ?r\gh a simple lev] or ,joy ,/ick :i* is pivot$ at its l[] end to ! floor4 ,! ,dep]duss9 or ,dep control is /&>d ) ! l>g] ma*9es & consi/s ( an inv]t$ ,u =m yoke on :i* is m\nt$ ! :eel = op]at+ ! ail]ons4 99,/ick ,control994 ,) ! /ick pivot$ at ! bottom1 a =w>d movem5t ( ! lev] causes ! ma*9e to desc5d :ile a backw>d movem5t or pull t[>d ! pilot causes ! a]oplane to head up or asc5d4 ,! /ick is connect$ ) ! elevators ) cross$ wires1 s t ! flaps move 9 an opposite direction to ! ,/ick4 ,mov+ ! /ick f side to side op]ates ! ail]ons4 ,illu/ration3 ,/&>d ,/ick ,control & ,movem5ts ,us$ 9 ! ,u4,s4,a4 99,dep]duss9 ,control994 ,a ,u %ap$ yoke1 ei!r ( b5t wood or /eel tube1 is pivot$ ! be>]s at ! sides ( ! fuselage4 ,wires are atta*$ to ! bottom ( ! yoke s t its back & =? movem5t is communicat$ to ! elevator flaps4 ,on ! top1 & 9 ! c5t] ( ! yoke1 is pivot$ a h& :eel ( ! automobile /e]+ type4 ,?is is provid$ ) a pulley & is connect$ ) ! ail]on flaps 9 su* a way t turn+ ! :eel t[>d ! high w+ tip causes x to desc5d4 ,pu%+ ! yoke =w>d & away f ! aviator causes ! ma*9e to desc5d1 :ile a rev]se movem5t raises ! nose4 ,! ,dep control is reliable & p[]ful b is bulky & heavy1 & requires a wide body 9 ord] to all[ room = ! pilot4 ,illu/ration3 ,foot ,rudd] ,b> ,us$ 9 ! ,/&>d ,h-#c4 ,c\rtesy ,a]ial ,age4 99,rudd] ,control994 ,foot b> control = ! rudd] is /&>d ) bo? ! /ick & ,dep controls4 ,! foot b> is connect$ ) ! rudd] 9 su* a way t ! a]oplane turns opposite to ! movem5t ( ! foot b> 9 ! mann] ( a boat4 ,t is1 pu%+ ! "r end ( ! b> =w>d causes ! ma*9e to turn t[>d ! "r4 ,illu/ration3 ,automatic ,control ,sy/em 7,sp]ry7 ,in/all$ 9 ,fuselage ( ,curtiss ,tractor ,biplane4 ,,*apt] ,,xvi4 ,,head ,,resi/ance ,,calculations4 99,effect ( ,resi/ance994 ,resi/ance to ! =w>d motion ( an a]oplane c be divid$ into two classes1 7#a7 ,! resi/ance or drag due to ! lift ( ! w+s1 & 7#b7 ,! useless or ,p>asitic resi/ance due to ! body1 *assis & o!r /ructural p>ts ( ! ma*9e4 ,! total resi/ance is ! sum ( ! w+ drag & ! p>asitic resi/ance4 ,s9ce e p\nd ( resi/ance calls = a def9ite am\nt ( p[]1 x is ( ! greate/ importance to r$uce ?is loss to ! l[e/ possible am\nt4 ,! adoption ( an effici5t w+ section means little if !re is a high resi/ance body & a tangle ( useless /ruts & wires expos$ to ! air /ream4 ,! resi/ance has a mu* great] effect on ! p[] ?an ! weight4 99,weight & ,resi/ance994 ,we h se5 t ! av]age mod]n w+ section w lift ab\t #af times ! value ( ! horizontal drag1 t is1 an addition ( #af p\nds w be equal to #a p\nd ( head resi/ance4 ,if1 by unnecess>y resi/ance1 we %\ld increase ! drag by #aj p\nds1 we might z well ga9 ! b5efit ( #aj x #af #afj p\nds ( useful load4 ,! high] ! lift-drag effici5cy ( ! w+1 ! great] w be ! proportional loss by p>asitic resi/ance4 99,glid+ ,angle994 ,! glid+ angle1 or ! incl9ation ( ! pa? ( desc5t :5 ! ma*9e is op]at+ )\t p[]1 is det]m9$ by ! weight & ! total head resi/ance4 ,) a con/ant weight ! angle is greate/ :5 ! resi/ance is highe/4 ,aside f consid]ations ( p[]1 ! glid+ angle is ( ! greate/ importance f ! /&po9t ( safety4 ,! less ! resi/ance1 & ! flatt] ! angle ( desc5t1 ! great] ! l&+ radius4 ,num]ically ?is angle c be express$ by3 ,glide ,w_/,r1 :]e ,w ! weight ( ! a]oplane1 & ,r total resi/ance4 ,?us if ! weight is #bejj p\nds & ! head resi/ance is #ejj p\nds1 ! rate ( glide w be3 #bejj_/ejj #e4 ,?is means t ! ma*9e w travel =w>d #e feet = e foot t x falls v]tically4 ,if ! resi/ance c\ld be decreas$ to #ajj p\nds1 ! rate ( glide w\ld be ext5d$ to #bejj_/ajj #be1 or ! a]oplane w\ld travel #be feet horizontally = e foot ( desc5t4 ,?is w give an idea z to ! value ( l[ resi/ance4 99,resi/ance & ,spe$994 ,! p>asitic resi/ance ( a body 9 uni=m air v>ies z ! squ>e ( ! velocity at ord9>y flight spe$s4 ,comp>+ spe$s ( #dj & #ajj miles p] h\r1 ! ratio w be z #dj is to #ajj #afjj3 #aj1jjj #f4be1 t is1 ! resi/ance at #ajj miles p] h\r w be #f4be times z great z at #dj miles p] h\r4 ,! above rem>ks apply only to bodies mak+ con/ant angle ) ! air /ream4 ,w+s & lift+ surfaces make v>y+ angles at diff]5t spe$s & h5ce d n %[ ! same rate ( increase4 ,9 c>ry+ a con/ant load1 ! angle ( ! a]oplane w+ is decreas$ z ! spe$ increases & up to a c]ta9 po9t ! resi/ance actually decreases ) an increase 9 ! spe$4 ,! w+ resi/ance is greate/ at extremely l[ spe$s & at v high spe$s4 ,z ! total resi/ance is made up ( ! sum ( ! w+ & p>asitic resi/ance at ! diff]5t spe$s1 x does n v>y accord+ to any fix$ law4 ,! only true k ( ! conditions exi/+ ?r\gh ! range ( flight spe$s is obta9$ by draw+ a curve 9 :i* ! sums ( ! drag & head resi/ance are tak5 at int]vals4 99,resi/ance & ,p[]994 ,! p[] consum$ 9 ov]com+ p>asitic resi/ance increases at a high] rate ?an ! resi/ance1 or z ! cube ( ! spe$4 ,?us if ! spe$ is increas$ f #dj to #ajj miles p] h\r1 ! p[] w be increas$ #ae4fc times4 ,?is c be %[n by ! foll[+3 ,let ,v velocity 9 miles p] h\r1 ,h ,horsep[]1 ,k ,resi/ance coeffici5t ( a body1 ,a ,total area ( pres5tation1 & ,r resi/ance 9 p\nds4 ,!n ,h ,,rv_/#cge4 ,s9ce ,r ,,kav1 !n ,h ,,kav x ,v_/#cge ,,kav_/#cge4 99,resi/ance & ,altitude994 ,! resi/ance decreases ) a r$uction 9 ! d5sity ( ! air at con/ant spe$4 ,9 practice1 ! resi/ance ( an a]oplane is n 9 direct proportion to a decrease 9 ! d5sity z ! spe$ mu/ be increas$ at high altitudes 9 ord] to obta9 ! lift4 ,! foll[+ example giv5 by ,capt4 ,gre5 w %[ ! actual relations4 ,tak+ an altitude ( #aj1jjj feet above sea level :]e ! d5sity is #j4gd ( t at sea level1 ! resi/ance at equal spe$s w be practically 9 proportion to ! d5sities4 ,9 ord] to ga9 su/5tation at ! high] altitude1 ! spe$ mu/ be increas$1 & h5ce ! true resi/ance w be f> f t calculat$ by ! relative d5sities4 ,assume a sea level spe$ ( #ajj ft4_/sec41 a weight ( #cjjj p\nds1 a lift-drag ratio ( ,l_/,d #ae1 & a body resi/ance ( #dj p\nds at sea level4 ,because ( ! *ange 9 d5sity at #aj1jjj feet1 ! fly+ spe$ w be increas$ f #ajj feet p] second to #cej feet p] second 9 ord] to obta9 su/5tation4 ,) sea level d5sity ?is increase 9 spe$ 7#c4e times7 w\ld increase ! body resi/ance #c4e x #c4e #ab4be times1 mak+ ! total resi/ance #ab4be x #dj #dij p\nds4 ,s9ce ! d5sity at ! high] altitude is only #j4gd ( t at sea level1 ?is w be r$uc$ by #j4bf1 or #j4bf x #dij #cfd p\nds4 ,?us1 ! f9al practical result is t ! sea level resi/ance ( ! body 7#dj p\nds7 is increas$ #i4a times because ( ! spe$ increase necess>y = su/5tation4 ,s9ce ! w+ angle & h5ce ! liftdrag ratio w\ld rema9 con/ant "u bo? conditions1 ! w+ drag w\ld be con/ant at bo? altitudes1 or #cjjj_/ae #bjj p\nds4 ,! total sea level resi/ance at #ajj feet p] second is #bjj #dj #bdj p\nds1 :ile ! total resi/ance at #aj1jjj feet becomes #cfd #bjj #efd p\nds4 ,! spe$ v>ies z ! squ>e root ( ! *ange 9 d5sity p]c5tage4 ,if ,v velocity at sea level1 v velocity at a high] level1 & d p]c5tage ( ! sea level d5sity at ! high] altitude1 !n v ,v_/,d4 ,:5 ! velocity at ! high altitude is ?us det]m9$1 ! resi/ance c be easily obta9$ by ! me?od giv5 9 ,capt4 ,gre5's article4 ,! foll[+ table gives ! p]c5tage ( d5sities ref]r$ to sea level d5sity4 ,altitude ,feet ,d5sity ,p]c5t ,altitude ,feet ,d5sity ,p]c5t ,sea-level #a4jj #g1ejj #j4gh #a1jjj 4#ig #aj1jjj 4#gd #b1jjj 4#ie #ab1ejj 4#ff #c1jjj 4#ia #ae1jjj 4#fa #e1jjj 4#he #bj1jjj 4#eb ,if ! velocity at sea level is #ajj miles p] h\r1 ! velocity at #bj1jjj feet w be #ajj_/j4gb #aci miles p] h\r1 :]e #j4gb is ! squ>e root ( ! d5sity p]c5tage1 or ! squ>e root ( #j4eb 4#gb at #bj1jjj feet4 99,total ,p>asitic ,resi/ance994 ,aside f ! drag ( ! w+s1 ! resi/ance ( ! /ructural p>ts1 body1 tail & *assis dep5ds ^u ! size & type ( a]oplane4 ,a spe$ sc\t has less resi/ance ?an a l>g] ma*9e because ( ! small am\nt ( expos$ brac+1 al?\gh ! relative resi/ance ( ! body is mu* great]4 ,! type ( eng9e also has a great influ5ce on ! p>asitic resi/ance4 ,! foll[+ gives ! approximate di/ribution ( a mod]n fight+ a]oplane3 ,body #fb p]c5t ,l&+ ge> #af ,tail1 f91 rudd] #g ,/ruts1 wires1 etc4 #ae ,! body resi/ance is by f> ! greate/ item4 ,a great "p ( ! body resi/ance c be attribut$ to ! motor cool+ sy/em1 s9ce 9 ei!r case x is div]t$ f ! true /reaml9e =m 9 ord] to accommodate ! radiator1 or ! rot>y motor c[l4 ,! body resi/ance is also influ5c$ by ! necessity ( accommodat+ a giv5 c>go or pass5g]-c>ry+ capacity1 & by ! di/ance ( ! tail surfaces f ! w+s4 ,a body is n a /reaml9e =m :5 its l5g? greatly exce$s #f diamet]s4 99,calculation ( ,total ,resi/ance994 ,! ne>e/ approa* t we c make to ! actual head resi/ance by means ( a =mula is to adopt an expression 9 ! =m ( ,r ,,kv :]e ,k is a factor dep5d+ ^u ! size & type ( ma*9e4 ,! true me?od w\ld be to g ov] ! planes & sum up ! individual resi/ance ( all ! expos$ p>ts4 ,! p>ts ly+ 9 ! propell] slip /ream %\ld be increas$ by ! increas$ velocity ( ! slip /ream4 ,! p>asitic resi/ance ( biplanes weigh+ ab\t #ahjj p\nds w av]age ab\t1 ,r #j4jcf,v :]e ,v velocity 9 miles p] h\r4 ,biplanes av]ag+ #bejj p\nds give ,r #j4jdh,v4 ,ma*9es ( ! tra9+ or #b-seat] type weigh f #ahjj to #bejj p\nds1 & h an av]age head resi/ance di/ribution z foll[s3 ,body1 radiators1 %ields #ce4e p]c5t4 ,tail surface & brac+ #ad4i ,l&+ ge> #ag4b ,int]plane /ruts1 wires & fitt+s #bc4f ,ail]ons1 ail]on brac+1 etc4 #h4h ,! av]ages 9 ! above table diff] greatly f ! values giv5 = ! high spe$ fight+ ma*9e1 pr9cipally because ( ! l>ge control surfaces us$ 9 tra9+ ma*9es1 & ! diff]5ce 9 ! size ( ! motors4 ,) ! w+ drag be+ equal to ,d ,kx ,,av1 & ! total p>asitic resi/ance equal to ,r ,,kv1 ! total resi/ance c be express$ by ,rt ,kx,a,v ,,kv1 :]e ,k coeffici5t ( p>asitic resi/ance = diff]5t types & sizes ( ma*9es4 ,! value ( ,k = tra9+ ma*9es w av]age #j4jcf1 = ma*9es weigh+ ab\t #bejj p\nds ,k #j4jdh4 ,sc\ts & small ma*9es w be safe at ,k #j4jbh4 ,! w+ drag coeffici5t ,kx v>ies ) ! angle ( incid5ce & h5ce ) ! spe$4 ,= example1 we w assume t ! w+ drag 7,kx7 ( a sc\t biplane at #ajj miles p] h\r is #j4jjjae1 t ! area is #bjj squ>e feet1 & t ! p>asitic resi/ance coeffici5t is ,k #j4jbh4 ,! total resi/ance becomes3 ,r 7#j4jjjae x #bjj x #ajj x #ajj7 #j4jbh x #ajj x #ajj #cjj #bhj #ehj p\nds4 ,! =mula 9 ?is case w\ld be ,r ,kx,a,v #j4jbh,v4 99,/rut ,resi/ance994 ,! /ruts are ( z ne>ly /reaml9e =m z possible4 ,9 practice ! resi/ance mu/ be compromis$ ) /r5g?1 & = ?is reason ! /ruts hav+ ! lea/ resi/ance are n always applicable to ! practical a]oplane4 ,f ! be/ results publi%$ by ! ,n4 ,p4 ,l4 ! resi/ance 0 ab\t #ab4h p\nds p] #ajj feet /rut at #fj miles p] h\r4 ,! wid? ( ! /rut is #a in*4 ,a rectangul> /rut "u ! same conditions gave a resi/ance ( #ajd4d p\nds p] #ajj feet4 ,a safe value w\ld be #be p\nds p] #ajj feet at #fj miles p] h\r4 ,if a wid] /rut is us$1 ! resi/ance mu/ be increas$ 9 proportion4 ,) a great] spe$1 ! resi/ance mu/ be increas$ 9 proportion to ! squ>es ( ! velocity4 ,:5 ! /ruts are incl9$ ) ! w9d1 ! resi/ance is mu* decreas$1 & ?is is "o advantage ( a heavy /agg] 9 a biplane4 ,! ,f95ess ratio or ! ratio ( ! wid? to ! dep? ( ! section has a great effect on ! resi/ance4 ,) ! dep? equal to twice ! wid? measur$ across ! /ream1 a c]ta9 /rut section gave a resi/ance ( #bd4h p\nds p] #ajj feet1 :ile ) a ratio ( #c4e ! resi/ance 0 r$uc$ to #aa4d p\nds p] hundr$ feet4 ,beyond ?is ratio ! *ange is n z great1 = ) a ratio ( #d4f ! resi/ance only dropp$ to #aa4b p\nds4 99,radiator ,resi/ance994 ,= ! exact calculation ( ! radiator resi/ance x is fir/ necess>y to "k ! motor p[] & ! fuel consumption s9ce ! radiator area1 & h5ce ! resi/ance1 dep5ds ^u ! size ( ! motor & ! am\nt ( heat transmitt$ to ! jacket wat]4 ,an a]onautic motor may be consid]$ to lose z mu* ?r\gh ! wat] jackets z is develop$ 9 useful p[]1 s t on ?is basis we %\ld all[ ab\t #a4f squ>e feet ( radiation surface p] horsep[]4 ,?is figure is arriv$ at by ,j4 ,c4 ,hunsak] & assumes t ! w9d spe$ is #ej miles p] h\r 7#gc feet p] second74 ,! mo/ sev]e cool+ condition is met ) 9 climb+ at l[ spe$1 & x is "h assum$ t #ej miles p] h\r w repres5t ! l[e/ spe$ t w\ld be ma9ta9$ = any l5g? ( "t ) ! motor full out4 ,= a rac+ a]oplane t w n climb = any l5g? ( "t1 "o-half ( ! surface giv5 above w be suffici5t1 & if ! radiator is plac$ 9 ! propell] slip /ream x c be made relatively /ill small] z ! increas$ propell] slip at rapid rates ( climb p>tially (fsets ! additional heat+4 ,9 ! above calculations1 ,hunsak] does n take any p>ticul> type ( radiator into consid]ation1 m]ely assum+ a smoo? cool+ surface4 ,! ,rome-,turney ,company /ates t !y all[ #a4jh squ>e feet ( cool+ surface p] horsep[] = honeycomb radiators1 & #j4he squ>e feet = ! helical tube type4 ,! surface ref]r$ to means ! actual surface measur$ all ov] ! tubes & cells1 & does n ref] to ! front area nor ! ext]ior dim5sions ( ! radiator4 ,:ile a radiator may be made #be p]c5t small] :5 plac$ 9 ! slip/ream1 ! resi/ance is increas$ by ab\t #be p] c5t1 ) a v small sav+ 9 weight1 h5ce ! total sav+ is small1 if any4 ,side m\nt$ radiators h a l[] cool+ effect p] squ>e foot ?an ^? plac$ 9 any o!r position1 ow+ to ! fact t ! air mu/ pass ?r\gh a great] l5g? ( tube ?an :]e ! broad side faces ! w9d4 ,9 ! radiator section te/$ by ,hunsak]1 !re 7 ab\t #fd squ>e feet ( cool+ surface p] squ>e foot ( front face area1 b = absolute assurance on ?is po9t "o %\ld det]m9e ! ratio = ! p>ticul> type ( radiator t is to be us$4 ,! ,auto ,radiator ,manufactur+ ,corporation1 mak]s ( ! ,flexo copp] core radiators1 h publi%$ "s field te/s made "u practical conditions & = diff]5t types & me?ods ( m\nt+4 ,! f\r classes ( radiators describ$ are3 7#a7 ,front ,type1 9 :i* ! radiator is m\nt$ 9 ! end ( ! fuselage2 7#b7 ,side ,type1 m\nt$ on ! sides ( ! body2 7#c7 ,ov]head ,type1 m\nt$ above ! fuselage & ne> ! top plane2 7#d7 ,ov]-,eng9e ,type1 plac$ above & connect$ directly to ! motor1 z 9 ! ,/&>d ,h-#c4 ,! foll[+ table gives ! effectiv5ess ( ! diff]5t m\nt+s 9 t]ms ( ! frontal area requir$ p] horsep[] & ! cool+ surface1 ! area be+ 9 squ>e in*es 7,front face area ( radiator74 ,area 9 w9d ( type 7#c7 is half ! calculat$ frontal area s9ce "o core lies beh9d ! o!r3 ,tak+ ! value ( ! ,rome-,turney honeycomb radiator z #fj squ>e feet ( cool+ surface p] horsep[]1 ! frontal area p] horsep[] w be #j4jafi squ>e feet1 assum+ t ! radiator is approximately #f in*es ?ick4 ,?is am\nts to #b4dc squ>e in*es ( frontal area p] horsep[]4 99,example994 ,f9d ! approximate frontal area ( a ,rome-,turney type honeycomb radiator us$ ) a motor giv+ #ajj brake-horsep[]4 ,f9d ,resi/ance at #ej miles p] h\r 7#gc feet p] second74 ,class ( ,m\nt+ ,squ>e ,in*es ,cool+ ,surface ,p] ,h4,p ,p] ,h4,p4 ,squ>e ,in* ,front ,type #d4jj #aag4jj ,side ,type #g4bj #ajd4jj ,ov]head ,type #b4gj #aab4jj ,ov]-,eng9e ,type #e4jj #aba4jj 99,solution994 ,area ,a #j4jafi ,,hp #j4jafi x #ajj #a4fi squ>e feet4 ,! honeycomb portion ( surface = a squ>e radiator ( ! above area w measure #af4b x #af4b4 ,all[+ a #a-;in* wat] passage or frame all ar\nd ! core1 ! side ( ! complet$ squ>e radiator w measure #af4b #a #ah4b4 ,! diamet] ( a circul> radiator core ( ! same #a4fi x #add area w be #ag4d in*es1 s9ce ,d #a4fix#add_/j4ghed4 ,add+ ! wat] passage1 ! ov]all diamet] becomes #ag4d #a #a #ai4d in*es4 ,! r\nd honeycomb front radiator us$ on ! #ajj horsep[] ,curtiss ,baby ,sc\t measures #bj in*es4 ,hunak] f\nd ! resi/ance ( a honeycomb radiator to be ,r#j4jjjhad ,,av1 !re be+ #d honeycomb cells p] squ>e in*4 ,a area ( radiator 9 squ>e feet1 & ,v velocity 9 feet p] second4 ,adopt+1 = example1 a spe$ ( #gc feet p] second1 & an area equival5t to a #ai4d-;in* diamet] circul> radiator z above1 ! total resi/ance becomes3 ,r #j4jjjhad ,,av #j4jjjhad x #c4ax 7#gc x #gc7 #ac4cb p\nds1 at #ej ,m4 ,p4 ,h4 :]e ,a #c4a squ>e feet4 99,resi/ance ( ,*assis994 ,disc :eels 7,enclos$ spokes7 h a resi/ance ( ab\t "o-half t ( op5-wire :eels4 ,! ,n4 ,p4 ,l4 & ,eiffel h agre$ t ! resi/ance ( a :eel approximat+ #bf x #d has a resi/ance ( #a4g p\nds at #fj miles p] h\r 7,disc type74 ,= any o!r spe$1 ! :eel resi/ance w be ,r #a4g ,v_/#cfjj1 :]e ,v spe$ 9 miles p] h\r4 ,we mu/ also take into consid]ation ! axle1 *assis /ruts1 wir+1 %ock absorb]s1 etc4 ,! itemization ( ! *assis resi/ance1 z giv5 by ! ,n4,p4,l4 = ! ,b4,e4-#b biplane is z foll[s 7#fj miles p] h\r73 ,:eels #b7;a7#a4ge p\nds #c4e p\nds ,axle #b4j ,*assis /ruts & connections #a4a ,total *assis resi/ance7#c7fj ,,mph4 #f4f p\nds ,at any o!r spe$1 ! resi/ance = ! complete *assis c be giv5 by ! =mula ,r #f4f,v_/#cfjj4 ,?is all[ance w be ample1 z ! ,b4 ,e4-#b is an old type & is equipp$ ) skids4 99,int]plane ,resi/ance994 ,! int]plane /ruts & wires are difficult to e/imate by an approximate =mula1 ! only exact way be+ to figure up ea* item sep>ately f a prelim9>y draw+4 ,! resi/ance v>ies ) ! =m ( ! /rut or wire section1 ! l5g?1 & ! ?ickness4 ,! fact t "s ( ! /ruts lie 9 ! propell] slip/ream1 & "s outside ( x1 makes ! calculation d\bly difficult4 ,! only rec\rse t we h at pres5t is to analyze ! conditions on ! ,b4 ,e4-#b4 ,) /ruts approximat+ true /reaml9e =m1 a great p]c5tage ( ! total resi/ance is sk9 friction1 & z be=e expla9$1 ?is item v>ies at a less] rate ?an ! squ>e ( ! spe$4 ,accord+ to a numb] ( exp]im5ts on full size biplanes av]ag+ #aijj p\nds1 x has be5 f\nd t ! int]plane resi/ance 7,/ruts1 wires & fitt+s7 am\nts to ab\t #bd p] c5t ( ! total p>asitic head resi/ance ( ! entire ma*9e1 ! drag ( w+s n be+ includ$4 ,! maximum obs]v$ gave #bi p] c5t & ! m9imum #ae p] c5t4 ,! resi/ance ( ! int]plane brac+ ( spe$ sc\ts w be consid]ably less 9 proportion1 z !re are few] expos$ /ruts & cables on ?is type1 ! resi/ance probably av]ag+ #ae p] c5t ( ! total head resi/ance4 ,bas$ on ^! figures ! resi/ance ( ! int]plane brac+ c be express$ by ! foll[+ =mula1 9 :i* ,i resi/ance ( int]plane brac+ 9 p\nds1 & ,v translational spe$ 9 miles p] h\r3 ,i #j4jji ,v 7,= two-place biplanes weigh+ #aijj p\nds74 ,i #j4jjed,v 7,= biplane spe$ sc\ts or rac+ type biplanes74 99,/rut ,resi/ance994 ,! above e/imate includes wir+1 /rut fitt+s1 etc41 complete1 & also takes ! effect ( ! slip/ream into consid]ation4 ,a m accurate e/imate c be made on ! basis ( /rut l5g?4 ,to obta9 ?is unit value we h rec\rse to ! ,b4 ,e4-#b te/s4 ,! translational spe$ 9 #fj miles p] h\r 7#hh feet p] second7 & ! slip/ream is tak5 at #be feet p] second4 ,?is gives a total velocity 9 ! slip/ream ( #aac feet p] second4 ,! /ruts are #a in*es wide1 & v>y 9 l5g? f #c' #j to #f' #j4 ,9 ! slip/ream ! increas$ velocity increases ! resi/ance ( ! items by #fd p] c5t4 ,total runn+ l5g? #aaj'-j4 ,total resi/ance #aj4ha p\nds4 ,! resi/ance p] foot #aj4ha_/aaj #j4jii p\nds4 99,resi/ance ( ,wire & ,cable994 ,9 ?is e/imate we w take ! resi/ance giv5 9 ! ,b4 ,e4-#b te/s1 s9ce values are giv5 9 ! slip/ream z well z = ! out] portions4 ,9 ! translational /ream !re is #bdj' #j ( cable1 #gj' #j ( ,no4 #ab solid wire1 & #eb turnbuckles1 ! total giv+ a resi/ance ( #ch4aj p\nds4 ,9 ! slip/ream !re is #ej' #j ( cable & #cj' #j ( solid wire ) a resi/ance ( #aa4jj p\nds4 ,! total wire & cable resi/ance = ! w+s is !re=e #di4aj p\nds4 ,! resi/ance ( ! wire & cable comb9$ is #j4abg p\nds p] runn+ foot4 99,summ>y ( ,int]plane ,resi/ance994 ,! total int]plane resi/ance includes ! /ruts1 wires1 cables & turnbuckles1 a portion ( :i* are 9 ! slip/ream4 ,s9ce ! total head resi/ance ( ! entire ma*9e 7,b4,e4-#b7 is #adj p\nds at #fj ,m4 ,p4 ,h41 & ! int]plane resi/ance #aj4ha #di4aj #ei4ia p\nds1 ! relation ( ! int]plane resi/ance to ! total resi/ance is #dc p] c5t4 ,?is is mu* high] ?an ! av]age 7#bd p] c5t71 b ! ,b4,e4-#b is an old type ( ma*9e & ! numb] ( /ruts & wires 7 mu* great] ?an ) mod]n a]oplanes4 99,control ,surface ,resi/ance994 ,! resi/ance ( ! control surfaces is a v>iable quantity1 s9ce s mu* dep5ds ^u ! arrangem5t & =m4 ,ano!r v>iation occurr+ among ma*9es ( ! same make & type is due to ! v>i\s angles ( ! surfaces dur+ flight1 or at lea/ dur+ ! "t t !y are us$ 9 correct+ ! attitude ( ! ma*9e4 ,) ! elevator flaps or ail]ons depress$ to _! fulle/ ext5t1 ! drag is _m times t ) ! surfaces 9 neutral1 & z a g5]al ?+ ! controls are depress$ at ! "t :5 ! p[] dem& is ! greate/--t is1 on l&+1 fly+ sl[1 or 9 gett+ (f4 ,ail]ons 9 neutral c be consid]$ z be+ an integral "p ( ! w+s :5 !y are h+$ to ! w+ sp>4 ,9 ! old] types ( ,curtiss ma*9es ! ail]ons 7 h+$ midway betwe5 ! planes & ! resi/ance 0 always 9 exi/5ce1 :e!r ! ail]ons 7 9 neutral or n4 ,w+ w>p+1 9 g5]al1 c be assum$ z 9 ! case :]e ! w+s & ail]ons are comb9$4 ,) ail]ons built into ! w+s1 ! resi/ance ( ! ail]ons1 & _! wires & fitt+s1 c be tak5 z be+ ab\t #d p] c5t ( ! total head resi/ance4 ,) ! ail]on locat$ betwe5 ! two w+s1 ! resi/ance may run z high z #bj p] c5t ( ! total4 ,l ! ail]ons1 ! elevator surfaces & rudd] are v>iable 9 attitude & !re=e give a v>y+ resi/ance4 ,9 neutral attitude ! complete tail1 consi/+ ( ! rudd]1 /abiliz]1 elevator1 f9 & brac+1 w av]age ab\t #ae p] c5t ( ! total resi/ance1 x be+ und]/ood t a non-lift+ /abiliz] is fitt$4 ,) lift+ tails ! resi/ance w be increas$ 9 proportion to ! load c>ri$ by ! /abiliz]4 ,9 reg>d to ! tail resi/ance x %\ld be not$ t ^! surfaces are 9 ! slip/ream & are calculat$ accord+ly1 al?\gh ! velocity ( ! slip/ream is some:at r$uc$ at ! po9t :]e x enc\nt]s ! tail surfaces4 ,! total tail resi/ance ( ! ,b4 ,e4-#b is giv5 z #c4c p\nds4 99,resi/ance ( ,seaplane ,floats994 ,! usual type ( seaplane ) d\ble floats may be consid]$ z hav+ ab\t #ab p] c5t high] resi/ance ?an a simil> l& ma*9e4 ,"s =ms ( floats h less resi/ance ?an o!rs1 ow+ to _! bett] /reaml9e =m1 b ! above figure w be on ! safe side = ! av]age pontoon4 ,bas+ our =mula on a #ab p] c5t increase on ! total head resi/ance1 ! =mula = ! floats & brac+ w become3 ,rt #j4jjdcf,v :]e ,r#a resi/ance ( floats & fitt+s4 99,body ,resi/ance994 ,?is item is probably ! mo/ difficult ( any to compute1 ow+ to ! great v>iety ( =ms1 ! diff]5ce 9 ! eng9e m\nt+1 & ! disposition ( ! fitt+s & connections4 ,! resi/ance ( ! pilot's & pass5g]'s heads1 w9d %ields1 & propell] arrangem5t all t5d to increase ! difficulty ( obta9+ a correct value4 ,a]oplanes ) rot>y air-cool$ motors1 or ) l>ge front radiators h a high] resi/ance ?an ^? arrang$ ) o!r types ( motors or radiator arrangem5ts4 ,probably ! item hav+ ! greate/ influ5ce on ! resi/ance ( ! fuselage is ! ratio ( ! l5g? to ! dep?1 or ! f95ess ratio4 ,9 tractor monoplanes & biplanes1 ( ! s+le propell] type1 ! body is 9 ! slip/ream1 & comp5sation mu/ be made = ?is factor4 ,if x 7 n = ! motor & radiator1 ! tractor fuselage c\ld be made 9 true dirigible /reaml9e =m1 & w\ld !re=e pres5t less resi/ance ?an ! pres5t =ms ( practical bodies4 ,! necessity ( plac+ ! tail surfaces at a fix$ di/ance f ! w+s also involves ! use ( a body t is long] 9 proportion ?an a true /reaml9e =m1 & ?is factor alone introduces an excessive head resi/ance4 ,! ideal ratio ( dep? to l5g? w\ld seem to range f #a to #e4e or #a to #f4 ,! f95ess ratio ( ! av]age two-seat tractor is consid]ably great] ?an ?is1 rang+ f #a to #g4e or #h4e4 ,a s+le-seat ma*9e ( ! spe$-sc\t type c be made mu* %ort] & has m ne>ly ! ideal proportions4 ,! only possible way ( dispos+ ( ?is problem is to comp>e ! results ( w9d tunnel te/s made on diff]5t types ( bodies1 & ev5 ) ?is data at h& a lib]al all[ance %\ld be made because ( ! influ5ce ( ! connections & o!r accessories4 ,eiffel1 ! ,n4 ,p4 ,l41 & ! ,massa*usetts ,in/itute ( ,te*nology h made a numb] ( exp]im5ts ) scale models ( exi/+ a]oplane bodies4 ,x is f ^! te/s t we mu/ e/imate our body resi/ance1 h5ce a table ( ! results is atta*$1 ! approximate outl9es be+ %[n by ! figures4 ,z 9 calculat+ ! resi/ance ( o!r p>ts1 ! resi/ance ( ! body c be express$ by ,r ,kx,a,v1 :]e ,kx coeffici5t ( ! body =m1 ,a ,cross-sectional area ( body 9 squ>e feet 7,area ( pres5tation71 & ,v velocity 9 miles p] h\r4 ,! area ,a is obta9$ by multiply+ ! body dep? by ! wid?4 ,! area ( pres5tation ( a body #b' #f wide & #c' #j deep w be #b4e x #c #g4e squ>e feet4 ,! exp]im5tal data does n give a v ready comp>ison betwe5 ! diff]5t types1 z ! bodies n only v>y 9 %ape & size1 b are also %[n ) diff]5t equipm5t4 ,"s h tail planes & "s h n2 two are %[n ) ! heads ( ! pilot & pass5g] project+ above ! fuselage1 :ile ! rema9d] h ei!r a simple cock-pit op5+ or are entirely clos$4 ,! pres5ce ( ! propell] 9 two cases may h a great deal to d ) rais+ ! value ( ! exp]im5tal results4 ,! propell] 0 /ation>y dur+ ! te/s1 b x 0 not$ t ! resi/ance 0 consid]ably less :5 ! propell] 0 all[$ to run z a w9dmill1 driv+ ! motor4 ,?is latt] condition w\ld correspond to ! resi/ance 9 glid+ ) ! motor cut (f4 ,9 all cases1 except ! ,dep]duss91 ! bodies are cov]$ ) fabric1 & ! sagg+ ( ! clo? 9 flight w probably result 9 high] resi/ance ?an w\ld be indicat$ by ! solid wood or metal model us$ 9 ! te/s4 ,! pu%] type bodies give less resi/ance ?an ! tractors1 b ! additional resi/ance ( ! outrigg]s & tail brac+ w probably br+ ! total f> above ! tractor body4 ,9 ! accompany+ body *>t are %[n #g repres5tative bodies3 7a7 ,dep]duss9 ,monocoque ,monoplane ,body1 a s+le-seat]2 7b7 ,n4 ,p4 ,l4-#e ,tractor ,biplane ,body1 s+le-seat]2 7c7 ,b4 ,f4-#cf ,dirigible ,=m1 )\t propell] or cock-pit op5+s2 7d7 ,b4 ,e4-#c4 ,two-,place ,tractor ,body1 ) pass5g] & pilot2 7e7 ,curtiss ,,jn ,type ,tractor ,body1 ) pass5g]s1 *assis & tail2 7f7 ,f>man ,pu%] type1 ) motor1 propell] & expos$ pass5g]s2 7g7 ,n4 ,p4 ,l4 ,pu%] ,body1 b>e4 ,body 7a7 0 te/$ ) a #a_/e scale model at a w9d tunnel spe$ ( #bh met]s p] second1 ! resi/ance ( ! model be+ #j4cgg kilograms 7#j4hc p\nds74 ,body 7d7 9 model =m 0 #a_/af scale & 0 te/$ at #bj4e miles p] h\r1 at :i* spe$ ! resi/ance 0 #j4jafe p\nds4 ,model 7e7 0 #a_/ab scale & 0 te/$ at #cj miles p] h\r4 ,^! v>y+ te/ spe$s1 x w be se51 d n all[ ( a v accurate means ( comp>ison4 ,! resi/ance ( model 7e7 0 #j4acfe p\nds at ! specifi$ w9d-tunnel air spe$4 ,! spe$s giv5 9 ! above table are simply translational spe$s1 & are n correct$ = slip/ream velocity4 ,) a slip/ream ( #be p] c5t1 increase ! body resi/ance by #dj p] c5t4 ,x w\ld be safe to add an additional #aj p] c5t to make up = project+ fitt+s1 baggy fabric1 & scale v>iations4 ,s9ce a body ( approximately /reaml9e =m has a consid]able p]c5tage ( sk9 friction1 scale corrections = size & velocity are ev5 ( m importance ?an ) w+ sections4 ,no w9d-tunnel exp]im5ts c det]m9e ! resi/ance exactly because ( ! unc]ta9ty ( ! scale factor4 ,! resi/ance z giv5 9 ! table is also affect$ by ! proximity ( ! w+ & tail surfaces1 & by projections emanat+ f ! motor comp>tm5t4 ,x w be not$ t ! dirigible =m ,b4,f4-#cf is m>k$ly bett] ?an any ( ! o!rs1 be+ almo/ ( p]fect /reaml9e =m4 ,! ne>e/ approximation to ! ideal =m is ,n4,p4,l4-#e1 :i* has easy curves1 l[ resi/ance1 & is fairly symmetrical ab\t ! c5t] l9e4 ,because ( _! small size1 ! pu%] bodies or nacelles h a small total resi/ance1 b ! value ( ,kx is high4 ,illu/ration3 ,*>t ,%[+ ,=ms ( #g ,typical ,a]oplane ,fuselage 99,problem994 ,f9d ! resi/ance ( a ,curtiss ,tractor ,type ,,jn body ) a bread? ( #b' #f & a dep? ( #c' #c1 ! spe$ be+ #ij miles p] h\r4 ,! slip/ream is assum$ to be #be p] c5t1 ) an additional #aj p] c5t = add$ fabric loss1 etc4 ,illu/ration3 ,typical ,/ream ,l9e ,/rut ,con/ruction4 99,solution994 ,! cross-sectional area #b' #f x #c' #c ,a #h4ac squ>e feet4 ,! velocity ( translation is #ij ,m4 ,p4 ,h41 or ,v #hajj4 ,! value ( ! resi/ance coeffici5t is tak5 f ! table1 ,ko-#j4jjbgc4 ,! total resi/ance ,r ,kx,a,v #j4jjbgc x #h4ac x #hajj #agh4b p\nds4 ,s9ce a slip/ream ( #be p] c5t increases ! resi/ance by #dj p] c5t1 ! resi/ance 9 ! slip/ream is #aghb x #a4d #bdi4dh p\nds4 ,! addition ( ! #aj p] c5t = extra friction makes ! total resi/ance #bdi4dh x #a4a #bgd4dc p\nds4 ,! resi/ance ( ?is body1 us$ ) tw9 motors1 w\ld be #agh4b x #a4a #aif4jb1 b z a tractor ) ! body 9 ! slip/ream1 ! resi/ance w\ld be equal to #bgd4dc p\nds z calculat$ above4 ,,*apt] ,,xvii4 ,,p[] ,,calculations4 99,p[] ,units994 ,p[] is ! rate ( do+ "w4 ,if a =ce ( #aj p\nds is appli$ to a body mov+ at ! rate ( #cjj feet p] m9ute1 ! p[] w be express$ by #aj x #cjj #cjjj foot-p\nds p] m9ute4 ,z ! figures obta9$ by ! foot & p\nd units are usually inconv5i5tly l>ge1 ! ,horsep[] unit has be5 adopt$4 ,a horsep[] is a unit t repres5ts "w done at ! rate ( #cc1jjj foot-p\nds p] m9ute1 or #eej foot-p\nds p] second4 ,?us if a c]ta9 a]oplane (f]s a resi/ance ( #bjj p\nds1 & flies at ! rate ( #fjjj feet p] m9ute1 !n ! "w done p] m9ute w be equal to #bjj x #fjjj #a1bjj1jjj foot-p\nds4 ,s9ce !re are #cc1jjj foot-p\nds ( "w p] m9ute = ea* horsep[]1 ! horsep[] w be3 #abjjjjj_/ccjjj #cf4c4 ,z a]oplane spe$s are usually giv5 9 t]ms ( miles p] h\r1 x w be conv5i5t to conv]t ! foot-m9ute unit into ! mile p] h\r unit4 ,if ,h horsep[]1 ,r resi/ance ( a]oplane1 & ,v miles p] h\r1 !n ,h ,,rv_/#cge1 ! !oretical horsep[]1 )\t loss4 ,if an a]oplane flies at #ajj miles p] h\r & requires a propell] ?ru/ ( #cjj p\nds1 !n ! horsep[] becomes3 ,h ,,rv_/#cge #cjj x #ajj_/cge #hj horsep[]4 ,?is is ! actual p[] requir$ to drive ! ma*9e1 b is n ! eng9e p[]1 z ! eng9e mu/ also supply ! losses due to ! propell]4 ,! propell] losses are g5]ally express$ z a p]c5tage ( ! total p[] suppli$4 ,! p]c5tage ( useful p[] is kn[n z ! ,effici5cy4 ,! effici5cy ( ! av]age a]oplane propell] w v>y f #j4gj to #j4hj4 ,if e propell] effici5cy express$ z a decimal1 ! motor horsep[] becomes3 ,h ,,rv_/#cge;e4 ,to obta9 ! motor horsep[]1 divide ! !oretical horsep[] by ! effici5cy4 ,us+ ! complete =mula = ! solution ( an example 9 :i* ! flight spe$ is #ajj ,m4 ,p4 ,h41 ! resi/ance #bbe p\nds & ! effici5cy #j4ge1 we h3 ,h ,,rv_/#cge;e #bbe x #ajj_/cge x #j4ge #hj horsep[]4 99,p[] ,di/ribution994 ,s9ce p[] dep5ds ^u ! total resi/ance to be ov]come1 "p ( ! p[] w be us$ = driv+ ! lift+ surfaces & a "p = ov]com+ ! p>asitic resi/ance4 ,! p[] requir$ = driv+ ! w+s dep5ds ^u ! angle ( incid5ce1 s9ce ! drag v>ies ) e angle4 ,! w+ p[] v>ies ) e flight spe$1 ow+ to ! *anges 9 angle made necess>y to support ! con/ant load4 ,! p[] = ! w+s w be lea/ at ! spe$ & angle t corresponds to ! greate/ lift-drag ratio4 ,ow+ to ! l[ value ( ! ,l_/,d at v small & v l>ge angles1 ! p[] requirem5ts w be excessive at extremely l[ & high spe$s4 ,z ! p>asitic resi/ance increases z ! squ>e ( ! spe$1 ! p[] = ov]com+ ?is resi/ance w v>y z ! cube ( ! spe$4 ,x is ! p>asitic resi/ance t really limits ! high] spe$s ( ! a]oplane1 s9ce x increases v rapidly at velocities ( ov] #fj miles p] h\r4 ,! total p[] at any spe$ is ! sum ( ! w+ p[] & p[] requir$ = ! p>asitic resi/ance4 ,ow+ to v>iations 9 ! w+ drag & resi/ance at e po9t )9 ! flight range1 x is exce$+ly difficult to directly calculate ! total p[] at any p>ticul> spe$4 ,! w+ drag & ! resi/ance %\ld be calculat$ = e spe$1 & !n laid out by a graph or curve4 ,! m9imum propell] ?ru/1 or ! m9imum total resi/ance1 occurs approximately at ! spe$ :]e ! body resi/ance & w+ drag are equal4 ,! m9imum horsep[] occurs at a l[ spe$1 b n ! l[e/ spe$1 & ?is w diff] ) e ma*9e4 ,illu/ration3 ,fig4 #a4 ,p[] ,*>t ( ,bl]iot ,monoplane1 ,) ,outl9e ( ,w+ ,section4 ,! ,results ,7 ,tak5 ,f ,full ,size ,te/s ,made by ! ,engli% ,gov]nm5t4 ,fig4 #a is a set ( p]=mance curves drawn f ! results ( te/s on a full size ,bl]iot monoplane4 ,at ! bottom ! horizontal r[ ( figures gives ! horizontal spe$ 9 feet p] second4 ,! fir/ column to ! left is ! horsep[]1 & ! second column is ! resi/ance or drag 9 p\nds4 ,! f\r curves repres5t respectively ! body resi/ance1 w+ or plane resi/ance1 horsep[]1 & total resi/ance4 ,! horizontal l9e ,,av %[s ! available horsep[]4 ,x w be not$ t ! body resi/ance increases /eadily f #i p\nds at #ej feet p] second1 to #ahj p\nds at #ajj feet p] second4 ,! w+ resi/ance1 on ! o!r h&1 decreases f #cej p\nds at #ef feet p] second to a m9imum ( #acj p\nds at #hc feet p] second4 ,x w be not$ t ! angles ( incid5ce are m>k$ along ! w+-drag curve by small circles4 ,! incid5ce is #f at #ge feet p] second1 & #d at a little less ?an #he feet p] second4 ,! available horsep[] ,,av is #db4 ,?is is %[n z a /raight l9e1 al?\gh 9 ! majority ( cases x is slightly curv$ ow+ to v>iations 9 p[] at ! high] spe$s1 & to v>iations 9 ! propell] effici5cy4 ,at #ij feet p] second ! actual horsep[] curve crosses ! l9e ( available horsep[] ,,av4 ,beyond ?is po9t horizontal flight is no long] possible1 z ! p[] requirem5ts w\ld exce$ ! available horsep[]4 ,x w be not$ t ! l[e/ total resi/ance occurs ne> ! po9t :]e ! body & w+ resi/ance curves int]sect1 or 9 o!r words1 :]e ! body & w+ resi/ance are equal4 ,! m9imum horsep[] takes place at #fc feet p] second1 or at a po9t ne>ly #a_/c betwe5 ! l[e/ flight spe$ & ! highe/ spe$ atta9$ by ! available horsep[] 9 horizontal flight 7#ij ft_/sec74 ,! actual range ( flight spe$s is limit$ to po9ts betwe5 ! int]section ( ! ,horsep[] requir$ curve1 & ! ,available horsep[] curve4 ,by increas+ ! propell] effici5cy1 or by increas+ ! p[] ( ! motor1 ! available horsep[] l9e is rais$ & ! flight range increas$4 99,horsep[] ,= ,climb+994 ,up to ! pres5t we h only consid]$ horizontal flight4 ,! p[] available = climb+ is ! diff]5ce betwe5 ! p[] requir$ to ma9ta9 horizontal flight at any spe$1 & ! actual horsep[] t c be deliv]$ by ! propell]4 ,?us1 if ! actual p[] deliv]$ by a motor ?r\gh ! propell] is #he horsep[]1 & ! p[] requir$ = horizontal flight at t spe$ is #de1 !n we h3 #he-de #dj horsep[] available = climb+4 ,s9ce ! diff]5ce betwe5 ! driv+ p[] & ! p[] requir$ = horizontal flight is less at extremely l[ & high spe$s1 x is evid5t t we w h a m9imum climb+ res]ve at ! high & l[ spe$s4 ,consult+ ! p[] curve = ! ,bl]iot monoplane1 we see t ! p[] requir$ at #ef feet p] second is #dj horsep[]1 & at #he feet p] second x is #ch horsep[]4 ,at ! l[ spe$ we h a climb+ res]ve ( #dd-dj #d ,h4 ,p41 & at ! high] spe$ #dd-ch #f ,h4 ,p4 ,! maximum available horsep[] ,,av is #dd horsep[]4 ,! m9imum horizontal p[] requir$ is f\nd at #fc feet p] second1 ! climb+ res]ve at ?is po9t be+ #dd-bh #af horsep[]4 ,at #ee feet p] second1 & at #ij1 we w\ld n be able to climb1 z we w\ld only h suffici5t p[] to ma9ta9 horizontal flight4 ,if ,w total weight ( a]oplane1 c climb+ spe$1 & ,h horsep[] res]ve = climb+1 !n ! climb+ spe$ ) a con/ant air d5sity w be express$ by3 c #ccjjj;,h_/,w4 ,assum+ t ! weight ( ! ,bl]iot monoplane is #hjj p\nds1 & t we are to climb at ! spe$ ( ! greate/ p[] res]ve 7#af horsep[]71 our rate ( climb is3 c #ccjjj;,h_/w #ccjjj x #af_/hjj #ffj feet p] m9ute4 ,x %\ld be und]/ood t ?is is ! velocity at ! beg9n+ ( ! climb4 ,aft] prolong$ climb+ ! rate falls (f because ( dim9i%+ p[] & increas+ spe$4 ,mu* dep5ds ^u ! eng9e p]=mance at ! high] altitudes1 s t ! res]ve p[] = climb usually dim9i%es z ! ma*9e rises1 & h5ce ! rate ( climb dim9i%es 9 proportion4 ,! foll[+ table tak5 f actual fly+ te/s w %[ h[ ! rate ( climb decreases ) ! altitude4 ,^! ma*9es 7 equipp$ ) #aej ,h4 ,p4 ,hispano-,suisa motors4 ,x w be not$ t ! ,s4 ,p4 ,a4 ,d4 & ! ,bl]iot hold _! rate ( climb con/ant up to #ghjj feet altitude1 :i* is a feat t is und\bt$ly p]=m$ by v>y+ ! compression ( ! eng9e4 ,besides increas+ ! p[]1 ! rate ( climb c also be increas$ by decreas+ ! weight ( ! a]oplane4 99,maximum ,altitude994 ,! maximum altitude to :i* a ma*9e c asc5d is kn[n z its ,ceil+4 ,?is aga9 dep5ds on bo? ! a]oplane & ! motor1 b pr9cipally on ! latt]4 ,x has be5 not$ t ma*9es hav+ ! greate/ rate ( climb also h ! greate/ ceil+4 ,?us ! ceil+ ( a fa/ climb+ sc\t is high] ?an t ( a l>g] & sl[] ma*9e4 ,bas$ on ?is pr9ciple1 a writ] 9 ,flight has develop$ ! foll[+ equation = ceil+1 :i*1 ( c\rse1 assumes a uni=m decrease 9 d5sity4 ,let ,h maximum altitude1 h ! altitude at any "t t aft] ! />t ( ! climb1 & a ! altitude aft] a "t equal to twice ! "t t1 !n3 ,h h _/ 7#b - a_/h7 ,approximate values ( h & a may be _h f ! foll[+ table1 :i* are ! results ( a te/ on a c]ta9 a]oplane3 99,"t99 7,m9utes7 #j4j #b4e #e4j #g4e #aj4j #ab4e #ae4j #ag4e #bj4j #bb4e 99,altitude99 7,feet7 #j4jccjj #faej #hgcj #ajgfj #abfaj #adaij #aeecj #affej #agfjj ,if we assume t ! height is #ajgfj feet aft] ! fir/ #aj m9utes1 & t ! altitude aft] twice ?is "t 7#bj m9utes7 is #affej feet1 !n ! maximum ceil+ atta9$ w be3 ,h h _/ 7#b - a_/h7 #ajgfj _/ #b - #affej_/ajgfj #bc1ggj feet4 ,! use ( ?is =mula requires t ! climb be kn[n = c]ta9 "t int]vals be=e ! ceil+4 99,glid+ ,angle994 ,! glid+ angle ( ! w+s alone is equal to ! lift-drag ratio at ! giv5 angle4 ,! be/ or ,flatte/ glid+ angle is1 ( c\rse1 ! be/ lift-drag ratio ( ! w+--say on ! av]age ab\t #a 9 #af4 ,! glid+ angle ( ! complete ma*9e is consid]ably less ?an ?is1 ow+ to ! resi/ance ( ! body & /ructural p>ts4 ,?is g5]ally r$uces ! actual angle to less ?an #ab1 & 9 mo/ cases betwe5 #f & #h4 ,express$ 9 t]ms ( degrees1 tan ,r_/,w :]e ,r head resi/ance & ,w weight 9 p\nds4 ,fig4 #b is a diagram giv+ ! glid+ =ce diagram4 ,! plane desc5ds along ! glid+ pa? ,,ac1 mak+ ! angle ( incid5ce 774 ,:5 9 horizontal flight1 ! lift is along ,,ol & ! weight is ,,ow4 ,:5 desc5d+ on ! glid+ pa? ! lift ma9ta9s ! same relation ) ! w+1 b ! relative angle ( ! weight is alt]$4 ,! weight n[ acts along ,,og4 ,! drag is repres5t$ by ,,od1 ) ! propell] ?ru/ ,,op equal & opposite to x4 ,) ! weight con/ant1 ! lift ,,ol is decreas$ by ! angle s t ! total life ,l ,w cos 4 ,! action ( ! weight ,w produces ! propell+ compon5t ,,op t gives =w>d velocity4 ,! l9e ,,ab is ! horizontal gr\nd l9e4 ,if ! total lift-drag ratio is #h1 !n ! glid+ angle w be #a 9 #h1 or measur$ 9 degrees1 tan ,r_/,w #a_/h #j4abe4 ,f a trigonometric table x w be f\nd t ?is tang5t corresponds to an angle ( #g - #aj'4 ,x %\ld be not$ t ,r is ! total resi/ance & n ! w+-drag4 ,illu/ration3 ,fig4 #b4 ,glid+ ,angle ,diagram ,%[+ ,compon5t ( ,gravity ,t ,causes ,=w>d ,motion4 ,! ,glid+ ,angle ,dep5ds ,^u ! ,ratio ( ! ,resi/ance to ! ,weight4 99,complete ,p[] ,calculations994 ,kn[+ ! total weight & ! desir$ spe$1 we mu/ det]m9e ! w+ section & area be=e we />t on ! actual p[] calculations4 ,?is c ei!r be det]m9$ by empirical rules 9 ! case ( a prelim9>y inve/igation1 or by actual calculation by means ( ! lift coeffici5ts aft] ! approximate values are kn[n4 ,su/a9+ a giv5 weight1 we c v>y ! angle1 area1 w+ section1 or ! spe$1 ! *oice ( ^! items be+ regulat$ pr9cipally by ! p[]4 ,giv5 a small area & a great angle ( incid5ce1 we c support ! load1 b ! p[] consumption w be excessive because ( ! l[ value ( ! ,l_/,d ratio at high angles4 ,if small area is desir$1 a l>ge value ( ,ky due to a high lift-w+ section is pref]able to a l[ lift w+ at high angles4 ,9 g5]al1 ! area %\ld be s arrang$ t ! w+ is at ! angle ( ! maximum lift-drag ratio at ! rat$ spe$4 ,a l[ angle means a small] motor1 less fuel1 & h5ce a light] ma*9e4 ,?is selection involves consid]able difficulty1 & a numb] ( w+ sections & areas mu/ be tri$ by ! trial & error me?od until ! mo/ economical comb9ation is discov]$4 ,illu/ration3 ,graphical ,glid+ ,diagrams ( ,sev]al ,a]oplanes ,record$ 9 ,briti% ,army ,conte/ ( #aiab4 ,! fir/ consid]ation be+ ! total weight1 we mu/ fir/ e/imate ?is f ! requir$ live load4 ,?is c be e/imat$ f previ\s examples ( ne>ly ! same type4 ,say t our requir$ live load is #ffj p\nds1 & t a live load factor ( #j4cj is us$4 ,! total weight n[ becomes #ffj_/j4cjbbjj p\nds4 ,to make a prelim9>y e/imate ( ! area we mu/ f9d ! load p] squ>e foot4 ,an empirical =mula = biplane load+ reads3 w #j4jfe,v - #j4be :]e ,v maximum spe$ 9 ,m4 ,p4 ,h41 & w load p] squ>e foot4 ,if we assume a maximum spe$ ( #ij ,m4 ,p4 ,h4 = our ma*9e1 ! unit load+ is w 7#j4jfe x #ij7 - #j4be #e4f p\nds p] squ>e foot4 ,! approximate area c n[ be f\nd f #bbjj_/e4f #cic squ>e feet4 7,call #cij47 ,! m9imum spe$ is ab\t #dh p] c5t ( ! maximum1 or #dc ,m4 ,p4 ,h4 ,we c n[ *oose "o or m w+ sections t w come approximately to our requirem5ts by ! use ( ! basic =mula1 ,ky w_/,v4 ,at high spe$1 ,ky #e4f_/7ij x #ij7 #j4jjjfia4 ,at l[ spe$1 ,ky #e4f_/7dj x #dj7 #j4jjcjcj4 ,we mu/ *oose ! mo/ economical w+ betwe5 ^! limits ( lift1 & on ref]5ce to our w+ section tables we f9d3 ,x w\ld seem f ! above t ! *os5 area is a little too l>ge1 z ! majority ( ! ,l_/,d ratios at high spe$ are poor1 ! be/ be+ #aa4jj ( ! ,u4,s4,a4-#a4 ,! angles are small1 be+ negative 9 mo/ cases at high spe$4 ,:ile ! lift-drag ( ! ,r4,a4,f-#c is v good at l[ spe$1 x is v poor at high1 h5ce ! area = ?is section %\ld be r$uc$ to increase ! load+4 ,! ,r4,a4,f4-#f & ! ,u4,s4,a4-#a %[ up ! be/1 = !y are bo? ne> ! maximum lift at l[ spe$ & h fair ,l_/,d ratios at high spe$4 ,x w be se5 t = ! be/ results !re %\ld be a s]ies ( p[] curves drawn = ! v>i\s w+s & areas4 ,?is me?od is too complicat$ & t$i\s to take up "h1 & s we w use ,u4,s4,a4-#a1 :i* does n really %[ up s bad at ?is /age4 ,bo? ! ,r4,a4,f4-#f & ! ,u4,s4,a4-#a h be5 us$ ext5sively on ma*9es ( ! size & type "u consid]ation4 ,:ile we require ,ky #j4jjcjcj1 & ,u4,s4,a-#a gives #j4jjcafe1 we w n attempt to utilize ?is excess1 z x w be rememb]$ t we %\ld n assume ! maximum lift = reasons ( /ability4 ,! w+-drag at high spe$ w be #bbjj_/aa4j #bjj p\nds1 & at l[ spe$ x w be3 #bbjj_/aj4d #baa p\nds4 ,s9ce ! maximum ,l_/,d is #ag4h at #c1 :]e ,ky is #j4jjacc1 ! lea/ drag w be3 #bbjj_/ag4h #abd p\nds4 ,?is lea/ drag w occur at ,v ,v#e4f_/jjjacc #fe ,m4 ,p4 ,h4 ,! w+ drag = ea* spe$ mu/ n[ be divid$ by ! correction factor #j4he1 :i* conv]ts ! monoplane values ( drag into biplane values4 ,s9ce ?is is practically con/ant x does n affect ! relative values ( ,kx 9 comp>+ w+s1 b x %\ld be us$ 9 f9al results4 ,= ?is type ( ma*9e we w take ! total p>asitic resi/ance z r #j4jcf,v4 ,at #ij ,m4,p4,h41 r #j4jcf x #ij x #ij #bia4f p\nds4 ,at #fe ,m4 ,p4 ,h41 ! resi/ance is3 #j4jcf x #fe x #fe #aeb4a4 ,at ! extreme l[ spe$ ( #dc ,m4 ,p4,h4 we h r - #j4jcfx#dc x #dc #ff4ef p\nds4 ,! total resi/ance 7,r7 is equal to ! sum ( ! w+-drag & ! p>asitic resi/ance4 ,at #ij ,m4 ,p4 ,h4 ! total resi/ance becomes #bjj #bia4f #dia4f p\nds4 ,at #fe ,m4,p4,h4 ! total is #abd #aeb4a #agf4a1 & at #dc ,m4,p4,h4 x is #baa #ff4ef #bgg4ef p\nds4 ,! horsep[] is comput$ f ,h ,,rv_/#cge;e1 & at #ij ,m4 ,p4 ,h4 ?is is 3 ,h #dia4f x #ij_/cge x #j4hj #adg4e ,h4 ,p4 :]e #j4hj is ! assum$ propell] effici5cy4 ,at #fe ,m4 ,p4 ,h4 ! horsep[] drops to ,h #agf4a x #fe_/cge x #j4h #ch4a ,h4 ,p41 assum+ ! same effici5cy4 ,9 ! same way ! ,h4 ,p4 at #dc ,m4 ,p4 ,h4 r is #ci4h4 ,a table & p[] *>t %\ld be work$ out = a numb] ( sections & areas accord+ to ! foll[+ table4 ,! calculations %\ld be comput$ at int]vals ( #e ,m4 ,p4 ,h41 at lea/ ! l[] spe$s4 ,w+ drag is n correct$ = biplane int]f]5ce3 99,weight & ,p[]994 ,! weight lift$ p] horsep[] v>ies 9 ! diff]5t types ( a]oplanes1 ?is diff]5ce ly+ pr9cipally 9 ! res]ve all[$ = climb+ & horizontal spe$4 ,a spe$ sc\t may c>ry z little z #h p\nds p] horsep[]1 :ile a sl[ two-seat] may exce$ #bj p\nds p] horsep[]4 ,a r\gh e/imate ( ! horsep[] requir$ may be _h by divid+ ! total weight by ! weight p] horsep[] ratio = t p>ticul> type4 ,?us if ! unit ,h4 ,p4 load+ is #af p\nds & ! total weight is #cbjj1 !n ! horsep[] w equal #cbjj_/af #bjj horsep[]4 ,assum+ t ! live load w' is #j4cb ( ! total weight ,w1 !n ,w w'_/#j4cb4 ,if m lbs4 p] ,h4,p41 !n ,h ,w_/m or ,h w'_/#j4cbm4 ,tak+ ! case ( a tra9+ ma*9e :]e m #bj1 & ! live load is #fdj p\nds1 ! approximate horsep[] w be3 ,h w'_/#j4cbm #fdj_/j4cb x #bj #ajj horsep[]4 ,a spe$ sc\t c>ry+ #cbj p\nds useful load1 ) m #aj1 w require ,h #cbj_/j4cb x #aj #ajj horsep[]4 ,,*apt] ,,xviii4 ,,propell]s4 99,pr9ciples & ,use ( ,propell]s994 ,a propell] conv]ts ! en]gy ( ! eng9e into ! ?ru/ requir$ to ov]come ! resi/ance ( ! a]oplane4 ,to ma9ta9 flight ! ?ru/1 or =ce ex]t$ by ! propell]1 mu/ always equal ! total resi/ance ( ! a]oplane4 ,a total resi/ance ( #djj p\nds requires a propell] ?ru/ ( #djj1 & z ! resi/ance v>ies ) ! spe$1 ! eng9e revolutions mu/ be alt]$ correspond+ly4 ,! propell] is ! mo/ complicat$ & lea/ und]/ood elem5t ( ! a]oplane1 & we c b t\* only on ! mo/ elem5t>y features4 ,! incl9$ blades ( ! propell] ?r[ back an air/ream1 ! reaction ( :i* produces ! ?ru/4 ,! blades c also be consid]$ z a](oils mov+ 9 a circul> pa?1 ! lift ( ! a](oils correspond+ to ! ?ru/ ( ! propell]4 ,! reactions 9 any case are q complicat$ & require ! use ( high] ma!matics = a full und]/&+4 99,pit* & ,velocity994 ,:5 9 action ! propell] rotates1 & at ! same "t advances along a /raight l9e p>allel to its axis4 ,z a result1 ! tips ( ! propell] blades describe a curve kn[n z ,helix or screw-?read curve4 ,! action is v simil> to t ( a screw be+ turn$ 9 a nut4 ,= cle>ness 9 explanation we w call ! velocity 9 ! a]oplane pa? ! ,translational velocity1 & ! spe$ ( ! tips 9 _! circul> pa? z ! ,rotational velocity4 ,:5 a screw works 9 a rigid nut x advances a di/ance equal to ! ,pit* 9 ea* revolution1 ! pit* ( a s+le ?read$ screw be+ equal to ! di/ance betwe5 ! ?reads4 ,s9ce ! propell] or ,air screw works 9 a fluid1 !re is "s slip & ! actual advance does n correspond to ! ,pit* ( ! propell] blades4 ,! effective pit* is ! di/ance travel$ by ! propell] 9 "o revolution4 ,! actual pit* or ! angle ( ! blades mu/ be great] ?an ! angle ( ! effective helix by ! am\nt ( slip4 ,if ,n ,revolutions p] m9ute1 ,p effective pit* 9 feet & ,v translational velocity 9 miles p] h\r1 !n ,v ,,np_/#hh4 ,) an effective pit* ( #e feet1 & #abjj revolutions p] m9ute1 ! translational velocity ( ! a]oplane w be3 ,v #abjj x #e_/hhfh4b miles p] h\r4 ,illu/ration3 ,excelsior ,propell]1 an ,example ( ,am]ican ,propell] ,con/ruction4 ,?is ,propell] ,is ,built ,up ( ,lam9ations ( ,a%4 ,! actual pit* ( ! blades w\ld be f #ae to #be p] c5t great] ?an ! effective pit* because ( ! slip4 ,to h ?ru/ we mu/ h slip4 ,) ! translational velocity equal to ! blade-pit* velocity1 !re is no air/ream accel]at$ by ! blades1 & consequ5tly !re is no ?ru/ due to reaction4 ,! air ?r[n to ! re> ( a propell] moves at a great] spe$ ?an ! translation :5 ?ru/ is develop$1 & ?is /ream is kn[n z ! slip/ream4 ,! diff]5ce betwe5 ! translational & slip/ream velocity is ! slip4 ,! angle ( ! blade face det]m9es ! pit*4 ,! great] ! angle ( ! blade ) ! plane ( propell] rotation1 ! great] is ! pit*4 ,?is angle is measur$ f ! *ord ( ! work+ face ( ! table1 or f t side fac$ to ! re> ( ! blade4 ,9 ! majority ( cases ! work+ face is flat4 ,! front face is always heavily camb]$ l a w+ section1 ) ! greate/ ?ickness ab\t "o-?ird ! *ord f ! ent]+ edge4 ,z 9 ! case ( ! w+1 ! camb] is ( ! greate/ importance4 ,a uni=m pit* propell] has a v>y+ blade angle1 smalle/ at ! tip & increas+ t[>d ! hub4 ,) a uni=m pit* propell]1 e "p ( ! blade travels ?r\gh ! same =w>d di/ance 9 "o revolution1 h5ce x is necess>y to increase ! angle t[>d ! hub z ! inn]mo/ portions travel a small] di/ance ar\nd ! circle ( rotation4 ,!oretically1 ! angle at ! exact c5t] w\ld be #ij degrees4 ,! blade angles at ! diff]5t po9ts 9 ! l5g? ( a uni=m pit* propell] are obta9$ z foll[s3 ,draw a "r angle triangle 9 :i* ! altitude is made equal to ! pit*1 & ! base is equal to #c4adaf times ! propell] diamet]4 ,! angle made by ! hypot5use ) ! base is ! blade angle at ! tip4 ,divide ! base into any numb] ( equal spaces & connect ! division po9ts ) ! upp] angle4 ,! angles made by ^! l9es ) ! base are ! angles ( ! diff]5t blade sections4 99,blade ,=m994 ,! blade may be ei!r /raight-sid$ or curv$4 ,9 ! latt] case ! mo/ deeply curv$ edge is g5]ally ! ent]+ edge1 & ! maximum wid? is ab\t "o-?ird f ! tip4 ,mu* c>e is ex]cis$ 9 arrang+ ! outl9e s t ! c5t] ( pressure w n be locat$ 9 an ecc5tric position & ?us h>mfully di/ort ! blade :5 load$4 ,if ?is is n att5d$ to1 ! pit* w v>y accord+ to ! load4 ,9 "o make ( propell] ! blade is purposely made flexible s t ! pit* w accommodate itself correctly to diff]5t flight spe$s & conditions4 ,?is1 h[ev]1 is c>efully laid out s t ! flexure is proportional ?r\gh\t ! blade to ! *anges 9 ! load4 ,illu/ration3 ,! ,lang ,propell]1 ,hav+ ,/raight ,edges1 ,slightly ,tap]+ ,t[>d ! ,tips4 ,! ,tips ,are ,%ea!d ,) ,?9 ,copp] = ,protection ,aga9/ ,spray4 ,?is ,outl9e ,is ,(t5 ,kn[n z ! ,normale4 ,type ,f ! ,fr5* ,propell] ,fir/ ,us+ ,?is ,outl9e4 ,illu/ration3 ,a ,p>agon ,propell] ,) a ,curv$ ,lead+ ,edge4 ,! ,maximum ,wid? ,is ,ab\t ,"o-,?ird ! ,blade ,l5g? f ! ,tip & o4 ,t[>d ! ,tip ,s ,t ,x ,is ,v ,n>r[ at ! ,out] ,end4 ,! ,/eel ,propell] ,flange ,is ,%[n 9 ,place on ! ,hub4 99,propell] ,diamet]994 ,! l>ge/ propell]s are ! mo/ effici5t4 ,! propell] %\ld be z l>ge z c be safely swung on ! a]oplane4 ,l>ge1 sl[ revolution propell]s are f> sup]ior to ! small high spe$ type4 ,x is m economical to accel]ate a l>ge mass ( air sl[ly ) a l>ge diamet] ?an to spe$ up a small mass to a high velocity4 ,! diamet] us$ on any a]oplane dep5ds ^u ! p[] plant1 propell] cle>ance1 height ( *assis & _m o!r consid]ations4 ,approximately ! diamet] v>ies f ab\t #a_/c ! span on small spe$ sc\ts1 to #a_/e or #a_/f ( ! span on ! l>g] ma*9es4 99,air ,fl[994 ,! great] "p ( ! air is tak5 9 ?r\gh ! tips1 & is !n expell$ to ! re>4 ,?is condition prevails until ! blade angle is above #de degrees1 & f ?is po9t ! fl[ is outw>d4 ,ow+ to ! great angles at ! hub1 !re is little ?ru/ giv5 by ! inn] ?ird ( ! blade1 ! air 9 ?is region be+ simply *urn$ up 9 a directionless mass ( eddies4 ,at ! tips ! angle is small & ! velocity high1 :i* results 9 ab\t #hj p] c5t ( ! useful "w be+ p]=m$ by ! out] ?ird ( ! blade4 ,9 "s a]oplanes a sp9n] cap is plac$ ar\nd ! hub to r$uce ! *urn+ loss & to /reaml9e ! hub4 ,! blade section is v ?ick at ! hub = /ructural reasons4 ,! ,disc area ( a propell] is ! area ( ! circle swept out by ! blades4 ,x is ! pressure ov] ?is area t gives ! ?ru/1 & 9 "s me?ods ( calculation ! ?ru/ is bas$ on ! mean pressure p] squ>e foot ( disc area4 ,! pressure is n uni=mly di/ribut$ ov] ! disc1 be+ _m times great] at ! out] circumf]5ce ?an at ! hub4 ,! av]age pressure p] squ>e foot dep5ds ^u ! blade section & angle4 ,because ( ! great int5sity ( pressure at ! circumf]5ce1 ! effective /ream is 9 ! =m ( a holl[ tube4 99,numb] ( ,blades994 ,= tra9+1 & ord9>y "w1 two-blad$ propell]s are pref]able1 b = l>ge motors :]e ! sw+ is limit$1 ?ree or f\r blades are (t5 us$4 ,a multiple-blad$ propell] absorbs m horsep[] ) a giv5 diamet] ?an ! two-blade type4 ,9 g5]al1 a f\r-blad$ propell] revolv+ sl[ly may be consid]$ m effici5t ?an ! two-blade revolv+ rapidly4 ,:]e ! sw+ & cle>ance are small1 a small f\r-blade may give bett] results ?an a l>g] & fa/] two-blade4 ,a ?ree-blade (t5 %[s m>k$ sup]iority ov] a two-blade ev5 :5 ( small] diamet]1 & ! hub ( ! ?ree-blade is mu* /rong] ?an ! f\r-blade1 al?\gh nei!r ! ?ree or f\r is z /rong z ! two-blade type4 99,effects ( ,altitude994 ,at high altitudes ! d5sity is less1 & consequ5tly ! ?ru/ is less ) a giv5 numb] ( revolutions p] m9ute4 ,! ?ru/ c be ma9ta9$ ei!r by increas+ ! spe$1 or by increas+ ! pit*4 ,= correct s]vice at high altitudes ! propell] %\ld und\bt$ly be ( ! v>iable pit* type1 9 :i* ! pit* c be controll$ manually1 or by "s automatic means su* z proportional blade flexure4 99,effects ( ,pit*994 ,driv5 at a con/ant spe$1 bo? ! ?ru/ & horsep[] increase ) ! pit* up to a c]ta9 limit+ angle4 ,= a giv5 horsep[] ! /atic ?ru/ dep5ds bo? on ! diamet] & ! pit*4 ,if ! pit* is increas$ ! diamet] mu/ be decreas$ 9 proportion to ma9ta9 a con/ant spe$4 ,z ! pit* is regulat$ by ! translational spe$ & revolutions1 ! /atic ?ru/ ( a high spe$ ma*9e is v small4 ,z ! translational spe$ increases1 ! pit* relative to ! w9d is less1 & consequ5tly ! ?ru/ w pick up until a c]ta9 limit+ spe$ is rea*$4 99,?ru/ & ,horsep[]994 ,! calculation = ?ru/ & p[] are v complicat$1 b ! prim>y conditions c be giv5 by ! foll[+3 ,let ,v ! pit* velocity 9 feet p] m9ute1 ,t ?ru/ 9 p\nds1 & ,h horsep[]1 !n ,h ,,tv_/#ccjjj;,e f :i* ,t #ccjjj;,,he_/,v1 ! effici5cy be+ designat$ by ,e4 ,s9ce ! pit* velocity is ,,np1 :]e ,n revs4 p] m9ute & ,p pit* 9 feet1 !n ,t #ccjjj;,,he_/,,pn4 ,assum+ a #e-;foot pit*1 #abjj revs41 ! effici5cy #j4ge1 & ! horsep[] #ajj1 ! ?ru/ w be3 ,t #ccjjj x #ajj x #j4ge_/e x #abjj #dab4e p\nds4 ,! pit* 9 ?is case is ! blade pit*1 & ! great unc]ta9ty lies 9 select+ a prop] value = ,e4 ,?is may v>y f #j4gj to #j4he4 ,! diamet] is also an unkn[n factor 9 ?is primitive equation4 99,mat]ials & ,con/ruction994 ,! woods us$ = propell] con/ruction are spruce1 a%1 mahogany1 bir*1 :ite oak1 walnut1 & maple4 ,up to #ej ,h4 ,p4 spruce is suitable1 z x is light1 & /rong en\gh = ?is p[]4 ,9 ,europe walnut & mahogany are ! mo/ commonly us$1 al?\gh !y are v exp5sive4 ,bir* is v /rong & comp>atively light = its /r5g?1 & c be us$ successfully up to #abe horsep[]4 ,a% is /rong1 light & fibr\s1 b has ! objectionable feature ( w>p+ & _c )/& moi/ure4 ,maple is too heavy = its /r5g?4 ,:ite oak1 qu>t]-saw$1 is ! be/ ( propell] woods & is us$ ) ! v l>ge/ eng9es4 ,x is /rong = its weight & is h>d1 b is v difficult to "w & glue4 ,= tropical climates1 ,s\!rn popl> is frequ5tly us$ z x has ! prop]ty ( resi/+ heat & humidity4 ,"o-in* bo>ds are r\gh dress$ to #g_/h in* & !n f9i%$ d[n to #ac_/af or #c_/d in*4 ,aft] a ?or\gh too? plan+ to r\gh5 ! surface = ! glue1 !y are ?or\ghly coat$ ) hot hide glue1 pil$ toge!r 9 blocks ( f #e to #aj lam9ations1 & !n ?or\ghly squeez$ = #ah h\rs 9 a press or by clamps until ! glue has ?or\ghly set4 ,only ! be/ ( hide glue is us$1 appli$ at a temp]ature ( #adj;,f4 & at a room temp]ature ( #ajj4 ,! glue mu/ nev] be hott]1 nor ! bo>ds cool] ?an ! temp]atures /at$4 ,! propell] aft] be+ r\gh$ out is left to dry = t5 days s t all ( ! glue /resses are adju/$4 ,if less "t is tak51 ! propell] w w>p out ( %ape4 ,! propell] is work$ d[n )9 a small fraction ( ! f9i%$ size & is aga9 all[$ to re/4 ,aft] a few days x is f9i%$ d[n to size by h&1 is scrap$1 & te/$ = pit*1 track+ & hub dim5sions4 ,! f9i% is glossy1 & may be accompli%$ by sev]al coats ( sp> v>ni% or by repeat$ applications ( hot boil$ l9se$ oil well rubb$ 91 f9i%+ ) ?ree or f\r coats ( wax poli%4 ,!re %\ld be at lea/ #e applications ( l9se$ oil1 ! ?ird coat be+ s&pap]$ ) ,no4 #j pap]4 ,! wood %\ld be scrap$ to dim5sion & mu/ n be t\*$ ) s&pap] until at lea/ two coats ( v>ni% or oil h be5 appli$4 ,! wood mu/ be absolutely cle> & /raight gra9$1 & )\t discolorations4 ,! bo>ds mu/ be pil$ s t ! edge ( ! gra9 is on ! face ( ! blades1 & ! direction ( ! annul> r+s mu/ be alt]nat$ 9 ! adjac5t bo>ds4 ,illu/ration3 ,plan & ,side ,elevation ( ! ,s4,p4,a4,d4 ,spe$ ,sc\t4 ,c\rtesy ,a]ial ,age4 ,,*apt] ,,xix4 ,,op]ation ,,& ,,tra9+4 99,self-,tra9+994 ,9 ! e>ly days ( aviation1 !re 7 few s*ools1 & ^! 7 s exp5sive to att5d t ! majority ( ! a]onautical en?usia/s taught !mselves to fly on home-made ma*9es4 ,:ile ?is 0 a h]oic me?od1 x _h ! advantage ( giv+ ! /ud5t p]fect confid5ce 9 himself1 & if 8 funds 7 suffici5t to outla/ ! cra%es1 x result$ 9 a f9i%$ & ?or\gh fly]4 ,9 g5]al1 ?is process may be describ$ z consi/+ ( two h\rs ( practice foll[$ by a week or m ( repair+4 ,! pres5t-day beg9n] has _m advantages4 ,he has ! *oice ( _m excell5t s*ools t *>ge a reasonable tuition1 & :]e ! risk ( injury is small4 ,he has access to ! valuable notes publi%$ 9 ! a]onautical magaz9es1 & ! privilege ( consult+ ) exp]i5c$ aviators4 ,! /ability & reliability ( ! planes & ! motors h also be5 improv$ to a rem>kable degree1 & ! /ud5t no long] has to cont5d ) a d\btful a]oplane con/ruction nor ) ! :ims ( a poorly-con/ruct$ motor4 99,tra9+ ,me?ods994 ,9 ! majority ( ,am]ican s*ools1 ! in/ructor accompanies ! /ud5t 9 ! fir/ flights4 ,! controls are ,dual1 or int]connect$1 s t ! in/ructors' controls act 9 unison ) ^? ( ! /ud5t1 ?us giv+ ! latt] an accurate k ( ! movem5ts necess>y = ea* flight condition4 ,aft] ! fir/ few flights ! in/ructor c relax 8 controls at times s t ! /ud5t c take *>ge4 ,?is cont9ues until ! /ud5t has %[n ! ability to h&le ! ma*9e alone "u ord9>y conditions & is !n ready = 8 fir/ ,solo or flight alone4 ,! fir/ solo is a critical p]iod 9 8 tra9+1 = :5 once 9 flight he is beyond all human aid4 ,at ! navy tra9+ s*ool at ,p5sacola1 ! /ud5t is fir/ tak5 = a ride ) "o ( ! in/ructors )\t giv+ him access to ! controls4 ,?is is simply to give ! /ud5t an exp]i5ce 9 ! s5sation ( flight4 ,aft] ?is he is tak5 = a s]ies ( %ort flights on a dual control ma*9e1 ! in/ructor gradually all[+ him to take *>ge to a great] & great] ext5t z he develops ! ,air feel4 ,dur+ ?is "t ! intricacies ( ! maneuv]s are also gradually increas$1 s t aft] ab\t t5 h\rs ( ?is sort ( "w he is all[$ to take 8 fir/ solo4 ,x has be5 f\nd t ! av]age /ud5t w require f #aj to #bj h\rs ( dual control in/ruction be=e he is fit to fly alone4 ,:5 8 "w has prov5 satisfactory he is !n all[$ to fly 9 r\gh wea!r1 execute spirals1 & attempt high altitude & long di/ance fly+4 ,"s in/ructors believe 9 %[+ :at c be p]=m$ 9 ! air f ! v beg9n+4 ,dur+ ! fir/ dual flights1 ! pilot indulges 9 dives1 v]tical banks1 side slip1 or ev5 loop+4 ,aft] an exp]i5ce ( ?is sort1 ! /ud5t is f> m collect$ & easy dur+ ! foll[+ in/ructions 9 simple /raight fly+4 ,if ?is prelim9>y /unt fly+ has a v mat]ial effect on ! n]ve ( ! /ud5t x may be tak5 = grant$ t he is n adapt$ = ! "w & c be we$$ out )\t fur!r loss ( "t4 ,if he is ( ! "r type1 ?is r\gh /uff has a b5eficial influ5ce on 8 "w dur+ ! succe$+ lessons4 ,dur+ ?is "t num]\s l&+s are made1 = x mu/ be und]/ood t ?is is "o ( ! mo/ difficult features ( fly+4 ,) #ae m9ute lessons1 at lea/ #f l&+s %\ld be made p] lesson4 ,a second me?od ( in/ruction1 & to ! au?or's m9d ! mo/ desirable1 is by means ( ! ,p5gu9 or ,roll]4 ,?is is a l[-p[]$ ma*9e ) v small w+s--s small t x _c raise itself f ! gr\nd4 ,by runn+ ! p5gu9 ov] ! gr\nd1 ! /ud5t le>ns h[ to manage 8 eng9e & to /e] ) 8 feet4 ,9 ?is way he obta9s a c]ta9 delicacy ( t\* )\t endang]+ ei!r himself or an exp5sive ma*9e4 ,aft] he has progress$ satisfactorily on ?is ma*9e he graduates to a fa/] p5gu9 or else to a v sl[ a]oplane ) :i* he c actually leave ! gr\nd4 ,s9ce ! second p5gu91 or ! sl[ a]oplane are mu* fa/] ?an ! fir/ ma*9e1 ! /ud5t f9ds t ! s5sitiv5ess ( ! rudd] & controls are greatly increas$4 ,!y require m c>eful h&l+ ?an 9 ! fir/ in/ance1 & ! slighte/ mi/ake or delay w s5d ! ma*9e skidd+4 ,! a]oplanes us$ at ?is /age are v l[-p[]$1 & are capable ( ris+ only a few feet f ! gr\nd1 b !y give ! /ud5t an opportunity ( le>n+ ! ail]on & tail controls 9 comp>ative safety4 ,! same result c be obta9$ ) a /&>d a]oplane by a p]man5t set 9 ! ?rottle control1 & by adju/+ ! /abiliz] surface4 ,! beg9n] is all[$ to "w only dur+ calm wea!r1 z ! l[ spe$ & small lift+ capacity is likely to cause an accid5t if ! ma*9e is caught by a side or foll[+ gu/4 ,he only le>ns h[ to get ! ma*9e (f ! gr\nd1 to keep ! tail up & hold x 9 a /raight l9e = a few seconds4 ,! man taught by ! p5gu9 me?od is alone :5 he fir/ leaves ! gr\nd1 & h5ce is g5]ally m self-reliant ?an "o :o has be5 ,spoon f$4 ,8 exp]i5ce 9 h&l+ ! controls has made 8 movem5ts in/9ctive1 s t :5 he fir/ actually flies he is 9 a bett] position to analyze ! new problems be=e him4 ,x is a bett] & *eap] me?od = ! s*ool z ! breakage is less exp5sive & all[s ! unfit /ud5ts be we$$ out be=e !y cause damage to !mselves or to ! s*ool prop]ty4 99,gr\nd ,in/ruction994 ,be=e attempt+ flight1 ! /ud5t %\ld be ?or\ghly v]s$ 9 ! pr9ciples an con/ructional details ( ! a]oplane & ! a]onautic motor4 ,he %\ld "k h[ to take d[n1 "t & repair e type ( motor ) :i* he is likely to come into contact4 ,he %\ld be able to tell at a glance :e!r ! ma*9e is rigg$ or tru$ up prop]ly1 & h a g5]al k ( ! und]ly+ pr9ciples ( a]odynamics4 ,! /udy ( ^! subjects is ! function ( ! gr\nd s*ool4 ,at ?is s*ool ! /ud5t %\ld le>n ! assembl+ & adju/+ ( ! a]oplane /ructure & its balance4 99,types ,suitable = ,pilots994 ,!re is a great div]sity ( op9ion z to ! type ( man be/ suit$ = fly+4 ,9 ?is c\ntry ! gov]nm5t requirem5ts reg>d+ age & physical condition are v exact+1 :ile 9 ,europe x has be5 f\nd t physical condition is n an index to a man's ability z a pilot4 ,_m ( ! be/ ,fr5* pilots 7 9 su* bad %ape z to be reject$ by ! o!r bran*es ( ! army4 ,our m5 are well "u #cj ye>s ( age1 :ile 9 ,european s]vice !re are _m excell5t pilots well ov] #dj4 ,x is almo/ impossible to tell f ext]nal appe>ances :e!r a man c become a good pilot4 ,9 g5]al he mu/ be m intellig5t & bett] educat$ ?an ! av]age infantryman4 ,he %\ld n be subject to an attack ( ,n]ves1 nor become easily rattl$1 = su* a man c\rts disa/] 9 fly+4 ,_m exhibition fly]s ( reputation h prov$ absolute failures 9 milit>y s]vice4 ,a k ( me*anics w be ( great b5efit & has be5 ! salvation ( _m a pilot 9 active s]vice4 ,automobile or motorcycle exp]i5ce is p>ticul>ly valuable4 ,recklessness1 or a d>e-devil sort ( a disposition1 are f>!/ f be+ qualifications = an aviator4 ,su* a man %\ld n be p]mitt$ to fly1 = he is n only a con/ant m5ace to himself b to ev]yone else conc]n$4 99,le>n+ to ,fly ,alone994 ,x is ) ! greate/ hesitancy t ! au?or ent]s into a ,gr\nd c\rse ( flight in/ruction4 ,i c1 h[ev]1 li/ ! pr9cipal ?+s to avoid & "s ( ! ?+s to d1 b ?is w nev] take ! place ( actual field in/ruction & exp]i5ce4 ,! fir/ & la/ ?+ to rememb] is to ,proce$ sl[ly & ) caution4 ,nev] try a new /unt until y are absolutely sure t y h ?or\ghly ma/]$ ! prelim9>y /eps 9 /raight fly+4 ,ov]-confid5ce at ! beg9n+ is almo/ z bad z no confid5ce at all1 & ! greate/ difficulty met ) by in/ructors dur+ ! fir/ solo flights is to keep ! /ud5t f imitat+ ! maneuv]s ( ! m exp]i5c$ fly]s4 ,sp5d pl5ty ( "t roll+ or ,grass-cutt+ be=e attempt+ to leave ! gr\nd4 ,be sure t y c h&le ! rudd] ) accuracy1 & at fairly high spe$s be=e attempt+ to lift4 ,a few days sp5t 9 sitt+ 9 ! ma*9e 7motor dead71 & acqua9t+ y\rself ) ! controls is excell5t practice & c]ta9ly is n a loss ( "t4 ,) ! ma*9e 9 ! hang>1 move ! controls = imag9>y turns1 dips & o!r maneuv]s s t ! resi/ance1 rea* & limit ( control movem5t w come m naturally :5 ! ma*9e is mov+4 ,dur+ ! gr\nd roll+ p]iod1 ! elevator or /abiliz] %\ld be set s t x is impossible to leave ! gr\nd1 & ! motor %\ld be adju/$ s t x _c develop its full ?ru/4 ,?is w provide aga9/ an accid5tal lift4 ,be easy & g5tle 9 h&l+ ! controls1 = !y "w easily1 & h p[]ful effect at high spe$s4 ,! desp]ate f]vor ) :i* ! beg9n] g5]ally yanks at ! joy/ick is g5]ally ! v reason = 8 accid5ts4 ,d n />t (f at full spe$ )\t fir/ gett+ us$ to ! effect ( ! controls4 ,le>n to f9d ! location ( ! v>i\s devices s t y c rea* !m )\t look+ or )\t fumbl+4 99,! ,fir/ ,/raight994 ,by adju/+ ! /abiliz] & elevators s t ! latt] has a great] degree ( fre$om1 & by *ang+ ! motor s t x c be run at a slightly high] spe$1 we are 9 a position to attempt our fir/ flight4 ,be c>eful t ! adju/m5t w limit ! climb ( ! ma*9e1 & *oose only ! calme/ ( wea!r4 ,x %\ld be rememb]$ t ! a]oplane w get (f ! gr\nd at a l[] spe$ ?an t requir$ = full flight at high] altitudes1 ?is be+ due to ! cu%ion+ effect betwe5 ! w+s & ! e>?4 ,a ma*9e travel+ at a spe$ capable ( su/a9+ flight at a few feet above ! e>? w cause x to /all :5 x is high en\gh to lose ?is compression4 ,! adju/m5t %\ld be su* t ! ma*9e _c rise above ?is ,cu%ion1 & 9 ?is condition x is fairly safe = ! beg9n]4 ,9 mak+ ! fir/ runs "u ! new conditions ( adju/m5t1 ! /ud5t %\ld le>n to manipulate ! elevators s t !y w hold ! tail up 9 ! correct position1 t is1 ) ! *ord ( ! w+s ne>ly horizontal4 ,d n all[ ! tail skid to drag ov] ! gr\nd fur!r ?an necess>y4 ,at ?is po9t ! /ud5t %\ld be /rapp$ 9 ! seat by a quick-deta*able safety belt4 ,n[ comes ! te/4 ,get "u full headway ) ! tail well up1 tak+ c>e to run aga9/ ! breeze4 ,! spe$ increases rapidly1 !n ! motion & j> seem s(t]1 & ! motor ceases to ro> s l\dly4 ,!re is n[ a v di/9ct *ange 9 ! note ( ! motor4 ,y are (f4 ,at ?is po9t a v peculi> illusion takes place1 = y\r elevation ( a few feet seems ab\t a ?\s& times great] ?an x really is4 ,) ?is impression ! /ud5t usually tries to correct matt] by a sudd5 =w>d pu% on ! control lev] caus+ f9e dive & a sma%4 ,x mu/ be borne 9 m9d t only ! slighte/ movem5t ( ! controls %\ld be made1 & if ?is does n prove suffici5t aft] a mom5t or s1 advance !m /ill fur!r b v g5tly4 ,sudd5 movem5ts mu/ be avoid$4 ,at fir/ ! ,hops %\ld n ext5d ov] a hundr$ y>ds or s until ! /ud5t is sure ( 8 controls4 ,little by little !y c be increas$ 9 l5g? & height4 ,he %\ld practice = "s "t be=e attempt+ a flight ( m ?an a mile4 ,by ?is "t1 ! /ud5t w h le>n$ t ! l&+ is by f> ! mo/ difficult feature 9 fly+1 & he %\ld practice ?is incessantly be=e try+ flights 9 w9dy wea!r4 ,! ma*9e %\ld be head$ directly into ! w9d1 bo? 9 gett+ (f & 9 l&+1 especially 9 ! latt] case1 z a sudd5 foll[+ gu/ w t5d to /all a ma*9e or upset x4 ,) a head w9d1 ! lift is ma9ta9$ at a l[ spe$ & h5ce is an aid 9 a safe l&+4 ,:5 fly+ 9 /ill air !re is little if any use = ! ail]ons1 b 9 gu/s ! /ud5t w ne$ _! aid 9 ma9ta9+ lat]al balance4 ,aft] ! rudd] & elevator controls h be5 well le>n$ ! effect ( ! ail]ons c be tri$4 ,gu/y or squally wea!r mu/ be avoid$ at ?is po9t 9 ! tra9+1 & no turns %\ld yet be attempt$4 ,:5 ! /ud5t atta9s heights great] ?an a few feet he %\ld take great c>e 9 obta9+ a suffici5t gr\nd spe$ be=e try+ to get (f1 = if lift$ be=e ! full fly+ spe$ is atta9$ x is likely to /all4 ,fa/ climb+ at %>p angles is dang]\s unless a suffici5t gr\nd spe$ has be5 atta9$4 ,su/5tation is due to =w>d spe$1 & ?is mu/ n be =gott54 ,! quicke/ climb = gett+ ov] trees & o!r ob/ructions is obta9$ by ga9+ full spe$ on ! gr\nd be=e ! climb beg9s1 z ! p[] ( ! eng9e is aid$ by ! mom5tum ( ! ma*9e4 ,9 l&+ 9 small fields x is necess>y to br+ ! ma*9e to re/ z soon z possible1 & ?is /opp+ di/ance dep5ds to a great ext5t ^u ! attitude ( ! ma*9e :5 x fir/ t\*es ! gr\nd4 ,if x is l&$ s t ! *assis :eels & tail skid /rike ! gr\nd simultane\sly1 ! incid5ce is s great t ! w+s act z air brakes4 ,on l&+1 ! angle 9 any case %\ld be quickly increas$ pa/ ! angle ( maximum lift4 ,! lift is mu* r$uc$ & ! drag is increas$ by quickly pull+ ! control t[>d ! aviator4 ,?is also r$uces ! t5d5cy t[>d nos+ ov]4 ,a normal l&+ 9 a l>ge field c be affect$ by fir/ />t+ d[n at ! normal glid+ angle1 & :5 f tw5ty to ?irty feet above ! gr\nd ! elevator control is pull$ back s t ! ma*9e w describe a curve tang5t to ! gr\nd4 ,9 /ud5t's practice ! curve %\ld n be exactly tang5t to ! gr\nd1 b tang5t to a level two or ?ree feet above ! gr\nd4 ,! ma*9e is n[ los+ spe$1 & to prev5t settl+ ! elevator %\ld be pull$ back a trifle4 ,! spe$ cont9ues to decrease until x settles d[n ?r\gh ! small rema9+ di/ance ) ! elevator full back4 ,! po9ts ( support %\ld /rike simultane\sly4 ,x is difficult = ! beg9n] to make ?is sort ( a l&+1 z !re always seems to be an uncontrollable desire to jam ! ma*9e d[n on ! gr\nd4 ,if a puff ( w9d happ5s to /rike ! ma*9e :5 a few feet (f1 ! /ud5t becomes rattl$ by ! sudd5ly increas$ elevation & jams h] d[n d\bly h>d4 99,w9d ,fly+994 ,! nature ( w9d at l[ altitudes is det]m9$ to a great ext5t by ! cont\r ( ! gr\nd4 ,eddies are caus$ by trees1 embankm5ts1 f5ces1 small hills1 etc41 :i* t5d to di/urb ! equilibrium or *ange ! c\rse ( ! a]oplane4 ,z ! altitude increases1 ! effects ( ^! ob/ructions are less pron\nc$1 until at f #bjjj to #cjjj feet ! effect is practically negligible4 ,w9ds t may be ,bumpy ne> ! gr\nd are fairly regul> :5 #cjjj feet is atta9$4 ,at ! high] altitudes ! velocity increases1 & if ! ma*9e is fly+ aga9/ ! w9d ! progress w naturally be mu* sl[] at ! high] altitudes4 ,:5 />t+ 9 a /rong w9d x is advisable to atta9 an altitude ( at lea/ #cjj to #djj feet be=e turn+4 ,turn+ 9 ) ! w9d c>ries ! possibility ( a drop or /all4 ,a %ort gu/ /rik+ ! ma*9e1 head on1 t5ds to ret>d ! velocity 9 reg>d to ! e>?1 b 9 reality increases ! relative air spe$ & ?us causes ! ma*9e to climb mom5t>ily4 ,a prolong$ head gu/ may produce a /all unless correct$ by ! elevator or met ) by res]ve p[]4 ,a re> gu/ r$uces ! relative w9d velocity & t5ds to make ! ma*9e /all1 al?\gh !re are a few cases :]e ! gu/ velocity has be5 great en\gh to cause a precipitate drop4 ,! high] ! spe$1 ! less ! dang] f re> gu/s4 ,! gu/s are mu* m pron\nc$ ) l[ w9ds1 say w9ds ( ab\t #e to #ae miles p] h\r1 & h5ce x is usually m tricky to fly 9 a w9d ( ?is velocity ?an ) a high] w9d4 ,x is n ! spe$ ( ! w9d s mu* z x is its v>iation f ! av]age velocity4 ,"o %\ld />t to "w on a bump at ! mom5t x fir/ />ts to appe>4 ,:5 fly+ ) ! w9d1 ! total spe$ 9 reg>d to ! e>? is ! sum ( ! w9d spe$ & ! a]oplane spe$4 ,:5 fly+ aga9/ x is ! diff]5ce betwe5 ! a]oplane & air spe$s4 ,?us1 if ! air spe$ ( ! a]oplane is #fj miles p] h\r1 ! spe$ 9 reg>d to ! gr\nd w be #ge miles p] h\r ) a foll[+ w9d ( #ae miles p] h\r1 & #de miles p] h\r :5 fly+ aga9/ a #ae-mile w9d4 ,! spe$ :5 fly+ across ! w9d w\ld be repres5t$ by ! diagonal ( a p>allelogram1 "o side ( :i* repres5ts ! a]oplane spe$1 & ! o!r side ! w9d spe$4 ,! angle ( ! diagonal is ! angle at :i* ! ma*9e mu/ be po9t$4 ,:5 view$ f ! gr\nd1 an a]oplane 9 a cross w9d appe>s to fly sideways4 99,turn+994 ,aft] ! beg9n] is able to ma9ta9 longitud9al & lat]al balance on /raight away flights1 he next attempts turns4 ,at fir/1 ! turns mu/ be ( great radius4 ,z ! radius is gradually %ort5$1 ! effects ( c5trifugal =ce become great]1 increas+ ! t5d5cy t[>d skidd+ or outw>d side slip4 ,to prev5t skidd+1 ! out] w+ tip mu/ be rais$ s t ! lift w oppose ! c5trifugal =ce4 ,! %ort] ! turn1 & ! fa/] x is made1 ! great] w be ! bank+ angle4 ,%\ld ! bank be too /eep1 ! gravitational =ce w pull ! ma*9e d[n1 & inw>dly 9 a direction p>allel to ! w+s4 ,?is is kn[n z an ,inn] side slip4 ,! bank+ may be p]=m$ by ! natural bank+ t5d5cy ( ! a]oplane or may be assi/$ by depress+ ! ail]on on ! out] w+ tip4 ,unless ! spe$ is well up to normal1 ! ma*9e w be likely to /all & drop on a turn1 z ! head resi/ance is mu* great] "u ^! conditions4 ,= safety "o %\ld take a %ort d[nw>d glide be=e />t+ ! turn1 s t ! spe$ w surely be suffici5t to c>ry x ar\nd ! turn4 ,a turn %\ld nev] be attempt$ :5 climb+ unless "o has a great res]ve p[]4 ,! comb9$ effects ( ! turn+ resi/ance1 & absorption ( en]gy due to ! climb1 w be almo/ c]ta9 to /all ! ma*9e4 ,!re are bank+ indicators on ! m>ket :i* w prove ( great s]vice4 ,^! op]ate on ! p5dulum pr9ciple & indicate graphically :e!r ! a]oplane is be+ held at ! correct angle ( bank4 99,prop] ,flight ,spe$994 ,an a]oplane %\ld always be provid$ ) an air spe$ met]1 giv+ ! spe$ ( ! ma*9e 9 relation to ! air4 ,:5 fly+ ) ! w9d ! pilot is likely to be confus$ by ! trem5d\s gr\nd spe$ at :i* 8 ma*9e is fly+4 ,:ile ! ma*9e may be mov$ at a fa/ clip 9 reg>d to ! e>?1 x may be really ne> ! /all+ spe$4 ,?is error is p>ticul>ly dang]\s :5 "o turns 9 ) ! direction ( ! w9d1 aft] fly+ aga9/ x = "s "t4 ,! sudd5 increase 9 ! e>? spe$1 :5 fully 9 ) ! w9d1 always creates a sudd5 desire to ?rottle d[n at ! v "t :5 ! relative air spe$ has already be5 greatly r$uc$ by ! turn4 ,/all+ due to ?is cause has result$ 9 _m accid5ts1 & ! beg9n] %\ld always atta9 an altitude ( a lea/ #ejj feet be=e he tries turn+ 9 ) a /rong w9d4 ,an accurate spe$ indicator elim9ates ?is dang] to a great ext5t1 b x %\ld be prov$ t ! in/rum5t itself is accurate be=e too mu* reliance is plac$ on x4 ,be=e ! adv5t ( ! indicator1 pilots 7 compell$ to e/imate ! spe$ by ! s5se ( feel1 "s dep5d+ ^u ! feel ( ! w9d pressure on _! faces1 & o!rs by ! relative resi/ance (f]$ to ! movem5t ( ! control surfaces4 ,! s5se ( ,air feel develop$ by ! late ,l9coln ,bea*ey 0 m>vel\s1 = )\t in/rum5ts he w\ld repeat$ly climb ne>ly into a /all :5 only #ej feet f ! gr\nd1 & !n recov] ) 8 *assis ne>ly dragg+ 9 ! we$s4 99,glid+ 7,fr4 ,vol ,plan7994 ,glid+ is a desc5t along an incl9$ pa? )\t p[]1 & is possible ) any a]oplane4 ,by suitably incl9+ ! w+s ) ! horizontal1 gravity is made to produce a =w>d propell+ compon5t t moves ! ma*9e =w>d at ! exp5se ( a loss 9 altitude4 ,! angle ( ! glid+ pa? made ) ! horizontal is kn[n z ! ,glid+ angle1 & indicates ! effici5cy ( ! a]oplane1 = ) ma*9es hav+ v l[ head resi/ance ! angle is v flat1 & m ne>ly approa*es ! horizontal4 ,! be/ or flatte/ glid+ angle is an inh]5t feature ( ! a]oplane design1 & ?is _c be exce$$ by any ef=t on ! "p ( ! pilot4 ,x is g5]ally express$ 9 t]ms ( ! ratio ( ! desc5t to ! =w>d di/ance travel$1 ?us a glid+ angle ( #aj means t ! a]oplane travels #aj feet horizontally = e foot ( desc5t4 ,any angle /eep] ?an ! flatte/ angle c be produc$ by pu%+ =w>d on ! elevator controls1 ?us depress+ ! elevator tips4 ,a v flat glid+ angle is a mo/ important feature f ! /&po9t ( safety1 z x det]m9es ! ext5t ( ! area )9 :i* a l&+ c be made ) a dead eng9e4 ,if ! glid+ angle is tak5 z #ab1 & ! height is #bjjj feet1 !n ! radius ( ! circul> area 9 :i* a l&+ is possible is #bjjj #ab #bdjjj feet1 & ! diamet] is twice ?is or #dh1jjj feet1 s t we c l& any:]e )9 a di/ance ( ov] #i miles4 ,if ! be/ glid+ angle ( ! ma*9e 7 only #aj1 ?is w be r$uc$ to #bjjj #aj #bjjjj feet1 h5ce our *ance ( *oos+ a safe l&+ space w\ld be cut d[n 9 proportion4 ,! be/ glid+ angle corresponds to a c]ta9 spe$ & w+ angle1 & mu/ be det]m9$ by exp]im5t1 b 9 _m ma*9es ! adju/m5t ( ! weight is su* t ! ma*9e automatically picks up ! be/ glide z soon z ! motor is cut (f1 & ne$s b little correction by ! elevators4 ,su* a ma*9e is div$ slightly :5 ! motor is cut out1 & !n aft] a few oscillations settles d[n & travels /eadily along ! prop] glid+ pa?4 ,9 try+ to improve ?is p]=mance1 ! spe$ indicator & incid5ce indicator %\ld be c>efully wat*$ s t nei!r ! /all+ angle nor ! /all+ spe$ are approa*$4 ,! be/ glide angle corresponds to ! be/ flight spe$ & w be increas$ if ! incid5ce is mu* bel[ or above ! incid5ce = ! mo/ economical flight spe$4 99,v]tical ,nose ,dive994 ,:5 ! a]oplane is div+ v]tically1 nose d[n1 ! c5t] ( pressure movem5t 9 "s ma*9es may oppose ! elevators1 ?us mak+ x difficult to /raight5 out into ! horizontal4 ,if pull+ full back on ! elevator control does n rem$y matt]s1 ! control %\ld !n be quickly rev]s$ s t !re is a mom5t>y t5d5cy to ?r[ ! ma*9e ov] on its back4 ,?is breaks up ! lock1 & :5 accompli%$1 ! controls %\ld be aga9 pull$ back to br+ ! ma*9e into ! horizontal ) ! elevators 9 ! orig9al /raight5+ out position4 ,! mom5tum sw+s ! ma*9e out & aga9/ ! lock+ position1 ?us aid+ ! controls 9 ov]com+ ! mom5t ( ! ,c4 ,p4 ,illu/ration3 ,typical ,glid+ ,angle ,diagram ,%[+ ,pa? ,incl9ation ( ,dep]duss9 ,monoplane4 99,tail ,sp9 7,sp9n+ ,nose ,dive7994 ,sp9n+ is due to side slipp+ or /all+1 & soon] or lat] e pilot gets into ?is position ei!r ?r\gh accid5t or int5tion4 ,if an accid5t1 x may be due to ! design ( ! a]oplane ?r\gh an improp] di/ribution ( ! v]tical surfaces1 or aga9 x may be caus$ by v /eep bank+ )\t an equival5t rate ( turn+4 ,incorrect manipulation ( ! ail]ons :5 ! ma*9e is ne> /all+ spe$1 or :5 glid+ 9 a spiral ( gradually decreas+ radius1 also causes ?is result4 ,at any rate1 ! side slip & /all are ! f9al cause ( sp94 ,9 ,/unt fly+1 :]e a sp9 is desir$1 "o ( ! quicke/ me?ods ( gett+ a sp9 is to pull ! controls all ! way back & pu% ! rudd] h>d ov] 9 ! desir$ direction ( sp9 ) ! motor %ut (f4 ,ano!r way to get a sp9 ) lots ( ,pep 9 x1 is pull ! /ick cle> back ) ! motor on1 & climb until ! ma*9e is /all$1 !n rudd] ov] h>d ) ! controls /ill held back4 ,! a]oplane w n[ fall ov] on its side 9 ! direction ( ! rudd]1 & assi/$ by ! motor :i* has aga9 cut 9 aft] ! peak ( ! climb1 w give all ! sp9 t any critic c\ld ask =4 ,aft] ! /all occurs1 ! motor %\ld be ?rottl$ d[n = x is likely to /ra9 ! plane or ev5 break x4 ,!re are sev]al ways ( com+ out ( ! sp94 ,probably ! be/ way1 & ! "o t causes ! lea/ loss ( altitude1 is to keep ! controls pull$ back all ! way1 & rudd] 9 ! opposite direction to ! sp9 7,motor cut out74 ,! rudd] w /op ! sp91 & ! elevator w cause ! plane to level out ( ! dive simultane\sly1 b ! controls %\ld be put into neutral z soon z level$ out or !re w be ano!r sp9 />t$ 9 ! opposite direction4 ,a v common me?od us$ by exhibition fly]s is fir/ put ! controls into neutral1 & rudd] opposite to ! sp9 until x /ops turn+ & x is !n put into a nose dive4 ,! /raight nose dive c !n be easily correct$ by pull+ back on ! controls until x levels out4 ,?is latt] me?od develops an excessive spe$ & requires a high altitude4 ,:5 ! a]oplane is ov]bank$ at normal spe$1 & ! turn is n correspond+ly rapid1 ! plane w slip d[n sideways into an ,inside side slip4 ,! /rong upw>d w9d aga9/ ! side ( ! body w turn ! nose into a dive1 ! nose drops1 & ! tail w !n />t to sw+ ar\nd 9 a circle l>g] ?an ! circle describ$ by ! nose--! dive cont9u+4 ,:5 mu* bel[ ! normal flight spe$1 or ne> ! /all+ po9t1 ! inn] ail]ons are n z effective :5 mak+ a %>p turn = _! velocity is mu* r$uc$4 ,:5 fully depress$1 ! inn] ail]ons give v little lift t[>d right+ ! ma*9e b add to ! drag & t5d to sp9 ! ma*9e ar\nd ) ! inn] tips act+ z a c5t] ( rotation4 ,! out] ail]ons are v effective & because ( ! high spe$ ( ^! tips1 !re is a /rong bank+ t5d5cy t ev5tually w result 9 side slip & a sp9 if ! pilot is n exp]i5c$4 ,ei!r ! sp9 due to ov]bank+1 or t due to l[ spe$ may be /raight5$ out accord+ to in/ructions already giv54 ,:5 a turn is attempt$ at l[ spe$ ne> ! gr\nd1 ! /ud5t g5]ally fails to bank up suffici5tly ?r\gh fe> ( /rik+ ! gr\nd ) ! l[] w+ tip1 & !re=e gets into an outw>d side slip4 ,9 ! frantic ef=t to keep ! l[ w+ up & (f ! gr\nd he depresses ! l[ ail]on to ! full1 ?us increas+ ! drag on ! l[ side & />t+ ! sp94 ,v mu* to 8 surprise he f9ds t ?is actually drops ! l[ tip fur!r in/ead ( rais+ x z ! out] tip is n[ spe$+ ar\nd at a trem5d\s clip1 & ! out] lift is increas+ ! bank aga9/ 8 w4 ,giv5 "t1 & altitude1 ! plane w bank up until x /&s on end1 & 9 any ev5t a bad side slip results1 & ! fun is on4 ,if ne> ! gr\nd z assum$1 ei!r ! side slip or ! result+ nose dive w soon t]m9ate matt]s4 ,! moral to be d]iv$ f ?is exp]i5ce is to keep up to spe$ 9 mak+ a turn1 to ma9ta9 a safe altitude1 & 9 case ! spe$ %\ld fall (f1 to depress ! 99out] ail]on994 ,! out] ail]on w resi/ ! sp9 if depress$1 z ! drag acts aga9/ ! sp91 & ! bank ?us obta9$ w act aga9/ ! out] side slip1 )\t de/roy+ ! velocity ( ! ma*9e z a :ole4 ,9 turn+ at /all+ spe$1 ! ail]on effects are rev]s$1 & z soon z /raight5$ out ! eng9e %\ld be op5$ up s t ! spe$ w be increas$ & ! l&+ made z easy z possible4 ,if ! f9 & rudd] surface is n suffici5t = ! ma*9e1 little is ga9$ by turn+ ! rudd] to an angle great] ?an #ae1 & 9 su* cases x is mu* m effective :5 held p>allel to ! w9d4 ,if correction has be5 />t$ be=e ! sp9 has develop$ great rapidity1 ! rudd] c fir/ be turn$ to *eck ! rotation & !n turn$ back p>allel to ! w9d4 ,x is always be/ to %ut (f ! eng9e :5 gett+ out ( a tail sp91 especially if ! eng9e rotation is 9 ! direction ( ! sp91 s9ce ! motor torque aids ! sp9 & acts aga9/ ! controls4 ,9 case ( a sma% !re is no dang] f fire ) ! eng9e cut out4 99,/unt ,fly+994 ,:5 ! /ud5t has _h #bj h\rs or m ( solo fly+1 & is capable ( p]=m+ ! ord9>y maneuv]s ) confid5ce & accuracy1 he is 9 a position to und]take /unt fly+ "u ! directions ( a good in/ructor 9 a dual control ma*9e4 ,?is trem5d\sly increases ! confid5ce ( ! /ud5t if gone ab\t 9 ! "r way1 & 9 8 aft] fly+ exp]i5ce enables him to get out ( tight places t w\ld o!rwise (t5 prove impossible4 ,!re is no d\bt b :at /unt fly+ has decreas$ ! p]c5tage ( accid5ts :5 prop]ly taught1 & t ,peg\d's orig9al /unt ( loop+ ! loop has be5 "o ( ! greate/ /eps 9 ! advancem5ts ( a]onautics t we h _h1 if only = ! fact t x taught ! fly] t !re 0 no fly+ attitude s bad b :at !re 0 a solution = x4 99,fly+ ,upside ,d[n994 ,) ! ma*9e on its back1 !n w+s are v ineffici5t1 & x is impossible to ma9ta9 horizontal flight 9 ?is position1 & ! ma*9e is also v un/able4 ,x %\ld really be call$ glid+ in/ead ( fly+ s9ce ! a]oplane con/antly loses altitude along an incl9$ glid+ pa?4 ,! di/ance t a ma*9e c be glid$ 9 ?is way dep5ds ^u ! skill ( ! pilot1 & x w also be f\nd t upside d[n flight ) a l>ge dih$ral is m difficult ?an ) /raight w+s4 ,! upside d[n flight beg9s ) a glide to ga9 spe$1 ! pa? be+ ab\t #bj ) ! horizontal1 & ?is spe$ ga9 is imp]ative s9ce x requires bo? ! p[] ( ! motor & ! mom5tum ( ! ma*9e to ov]come ! %>p climb = ! turnov]4 ,illu/ration3 ,upside ,d[n ,glide ,diagram1 ,%[+ ,successive ,positions ( ,a]oplane4 ,aft] suffici5t spe$ has be5 atta9$1 ! controls are pull$ back = a climb at ab\t a #fj angle1 z betwe5 7,a7 & 7,c71 ?is maneuv] be+ be/ p]=m$ ) ! glid+ pa? 7,c-,d7 aga9/ ! w9d4 ,) ! control pull$ back at 7,a71 ! rudd] is ?r[n ov] %>ply 9 ! desir$ direction ( ! turnov]1 & ?is w turn ! ma*9e ov] z indicat$ by at 7,b71 ! ma*9e f9ally gett+ on its back at ! peak ( ! climb 7,c74 ,) ! ma*9e on its back1 rev]se rudd] to /op ! ov]turn+1 & :5 ! w+s are horizontal1 ! rudd] %\ld be put 9 neutral to hold x 9 ?is position4 ,at 7,c7 ! motor is %ut (f1 & ! glide cont9u$ to 7,d7 :]e x is level$ out by a backw>d pull on ! controls4 ,?is %\ld always be p]=m$ at an altitude well ov] #bjjj feet4 ,illu/ration3 ,loop+ ,diagram ,%[+ ,successive ,positions ( ,ma*9e4 99,loop+994 ,?is is probably ! easie/ ( all /unts outside ( ! spiral glide4 ,x />ts ) ab\t a #bj glide z at 7,a7 to increase ! velocity 7,motor on71 & at ! beg9n+ ( ! loop at 7,b71 ! control lev] is pull$ back sl[ly4 ,! controls mu/ be pull$ back fa/] & fa/] z ! plane approa*es ! top ( ! loop1 a /eady pull produc+ ne>ly ! correct effect because ( ! decreas+ elevator resi/ance z ! ma*9e rea*es ! top ( ! loop at 7,c74 ,at ! top1 ! lev] %\ld be cle> back & mu/ be held 9 ?is position until at ! bottom 7,d7 :]e ! ma*9e leaves ! loop along ! incl9$ pa? 7,d-,e7 ,at 7,d71 ! /ick is pu%$ sl[ly =w>d to neutral1 gradually br+ ! ma*9e into ! horizontal4 ,! loops mu/ always be made :5 fly+ into ! w9d1 & ! fa/] !y are made ! bett]1 = !re is less /ra9 on ! frame & spe$ also prev5ts ! motor f cutt+ out at ! top ( ! loop4 ,illu/ration3 ,a ,few ,/raight ,loops & ,backw>d ,rev]se ,loops ,p]=m$ by ,niles4 ,illu/ration3 ,photograph ( ,night ,loop+ by ,*>les ,niles4 ,! ,ma*9e 0 ,provid$ ) ,railroad ,fl>es :i* ,left ! ,trace or ,pa? ( ! ,a]oplane on ! ! ,dry ,plate4 99,immelmann ,turn994 ,?is maneuv] 0 orig9at$ by ! ,g]man fly] ,immelmann1 & is mu* us$ 9 combat by bo? ! ,alli$ & ,g]man armies1 = x subjects ! enemy to a maximum field ( fire & enables ! ma*9e to make a quick getaway ) a s+le seat ma*9e4 ,) ! enemy ma*9e at 7,x71 & ) our ma*9e provid$ ) two ma*9e guns1 x w be se5 t ! enemy is "u ! fire ( ei!r ! rigid front gun or ! pivot$ cock-pit guns ?r\gh ne>ly ?ree-qu>t]s ( ! twi/+ loop4 ,! pivot$ gun :i* fires ov] ! top w+ is ! mo/ effective z x c rea* ! enemy ma*9e 7,x7 at 7,a71 7,b71 7,d7 & 7,e71 ! only bl9d spots occurr+ dur+ ! climb f 7,b7 to 7,d7 z indicat$ by ! p>tly roll$ ov] position at 7,c74 ,illu/ration3 ,successive ,positions 9 ,immelmann ,turn1 ,enemy ,ma*9e ,ei!r ,be+ at ,y or ,x4 ,x beg9s ) ! usual p[] glide 7,motor on7 at 7,a7 9 ord] to ga9 spe$1 & at ! beg9n+ ( ! #fj at 7,b7 ! elevator controls are pull$ back & ! rudd] giv5 a quick turn to ! extreme position 9 ! direction ( ! desir$ turnov]4 ,! rudd] action turns ! ma*9e ov] on its back at ! peak ( ! climb at 7,d7 )\t ! use ( ail]ons4 ,at ! top 7,d71 ! rudd] is ?r[n to ! opposite direction to /op ! roll ov] & is !n br\ght back to neutral to hold ! ma*9e flat on its back4 ,! elevator controls are held back until ! ma*9e comes out ( ! rev]se loop ext5d+ f 7,d7 to 7,e7 & until x leaves on ! horizontal at 7,f74 ,z ! object is to get away quick1 ! f9i% along 7,e-,f7 %\ld be made ) ! w9d1 & pref]ably %\ld be />t$ across w9d4 ,motor %\ld be ?rottl$ d[n f 7,d7 to 7,e7 to prev5t com+ out ) excessive spe$4 ,illu/ration3 ,positions 9 ,turn ,ov]1 ! ,ma*9e ,cont9u+ to ,rotate 9 ! ,same ,direction f ,b to ,d4 99,! ,roll-,ov]994 ,! />t ( ?is /unt is exactly l ! />t ( ! upside d[n glide or ! ,immelmann1 :ile ! f9i% is a sort ( rev]s$ ,immelmann1 ! ma*9e be+ /raight5$ out )\t go+ ar\nd a loop4 ,:5 at ! top ( ! turnov] climb1 ! rudd] is n rev]s$ & /raight5$ out z 9 ! ,immelmann1 b a little rudd] is kept on s z to cont9ue ! turnov] & br+ ! plane out on ! horizontal4 ,! rudd] action is assi/$ by a slight application ( ! ail]on :ile ! elevator control is pu%$ =w>d aft] ! ma*9e leaves ! peak ( ! climb4 ,i am indebt$ to ,lieut5ant ,*>les ,w4 ,ke5e = sugge/ions on ! ,immelmann & roll ov]1 & to ! late ,lieut5ant ,r4 ,c4 ,saufly ( ! ,u4 ,s4 ,navy = o!r items on tra9+4 ,illu/ration3 ,fly+ ,upside ,d[n ,) a ,bl]iot ,monoplane4 ,! ,plane is ,f> ,too ,l[ to ,recov] ,its ,normal ,position1 & z a ,result1 ! ,glide ,end$ ,fatally4 ,illu/ration3 ,an ,a]oplane ,equipp$ ) ! ,light ,boat ,hull ,%[n1 9 ?is ,figure is ,kn[n z a ,fly+ ,boat4 ,x ,diff]s f ! ,seaplane1 z ! ,floats or ,pontoons ( ! ,latt] ,d ,n ,enclose ! ,pass5g] & ,pilot4 ,,*apt] ,,xx4 ,,a]onautical ,,motors4 99,g5]al ,notes994 ,x is assum$ t ! read] und]/&s ! pr9ciples ( ! automobile motor & its accessories1 = a m9ute description ( gas-eng9e pr9ciples does n fall )9 ! scope ( ?is book4 ,if m in=mation is desir$ on ?is subject1 ! read] is ref]r$ to ! au?or's ,practical ,h&book ( ,gas1 ,oil & ,/eam ,eng9es4 ,only ^? features peculi> to a]onautic motors w be discuss$ 9 ?is *apt]4 99,a]onautic ,requirem5ts994 ,! pr9cipal requirem5ts ( an a]onautic motor are light weight1 l[ oil & fuel consumption1 reliability & compactness4 ,! outl9e z view$ f ! %aft end is also v important1 = ! motor mu/ be m\nt$ 9 a n>r[ /reaml9e body4 ,! compression pressures are mu* high] ?an ^? employ$ on auto motors1 & ! spe$ is g5]ally l[]4 ,) "o or two exceptions ! f\r-/roke cycle has be5 univ]sally adopt$4 ,a]onautic s]vice is a sev]e te/ = ! motor4 ,f ! />t to ! f9i% ( a flight1 ! a]oplane motor is on a /eady gr9d1 load$ at lea/ to #ge p] c5t ( its rat$ p[]4 ,! f\ndations are light & yield+ & ! air d5sity v>ies rapidly ) *anges 9 ! altitude4 ,z ! fuel & oil require an exp5diture ( p[] = _! support1 ! fuel consumption becomes ( great importance1 especially 9 long flights4 ,because ( ! heavy normal load ! lubricat+ sy/em mu/ be z ne>ly p]fect z x is possible to make x4 ,a motor c> runs normally at f #aj to #be p] c5t ( its rat$ horsep[]1 :ile ! a]o motor may develop z high z #ge p] c5t to #ajj p] c5t = h\rs at a "t4 ,a c> eng9e ( #fgb cubic in*es displacem5t is rat$ at #fe horsep[]1 :ile ! same size a]o eng9e has a rat+ ( #aed4 ,on ! basis ( normal output1 ?is ratio is ab\t #g to #a1 & tak+ ! weight ( ! a]o motor z "o-half t ( ! auto type1 ! true output ratio becomes #ad to #a4 ,up to ! "t ( a complete ov]haul 7#ej h\rs71 & at #ajj miles p] h\r1 ! av]age di/ance travel$ by ! a]o motor is #ejjj miles4 ,! equival5t motor c> mileage is #be1jjj1 & ! duration is ab\t #ajjj h\rs4 ,?is sugge/s ! necessity = improv$ mat]ials ( con/ruction4 ,ev5 on ! pres5t a]onautic motors ! fib] /ress 9 ! crank-%aft ranges f #abj1jjj to #adj1jjj p\nds p] squ>e in* aga9/ ! #hj1jjj-p\nd /ress us$ 9 auto %afts4 ,! crank case ( an a]onautic motor mu/ be p>ticul>ly rigid to )/& ! /resses due to ! light m\nt+1 & ?is dem&s a high] grade metal ?an t ord9>ily us$ ) automobiles4 ,unlike ! c> eng9e1 quality comes fir/ & price is a second>y consid]ation4 99,cool+ ,sy/ems994 ,bo? ! air & wat] cool+ sy/em is us$1 ! =m] = light fa/ a]oplanes su* z spe$ sc\ts1 & ! latt] = ! l>g] & m heavily p[]$ ma*9es4 ,ev5 9 "s types ( spe$ sc\ts ! air-cool$ motor has be5 displac$ by ! wat]-cool$1 ow+ to ! fact t ! air-cool] _c be built satisfactorily = outputs mu* great] ?an #aaj horsep[]4 ,by increas+ ! revolutions ( ! /ation>y wat]-cool$ type an increase 9 p[] may be _h ) ! same cyl9d]s1 b 9 ! case ( ! rot>y air-cool$ type ! spe$ is limit$ by ! c5trifugal =ces act+ on ! cyl9d]s4 ,illu/ration3 ,a #f-;,cyl9d] ,hall-,scott ,motor ,in/all$ 9 a ,m>t9 ,biplane4 ,:ile ! weight ( ! radiator1 wat] & pip+ increase ! weight ( ! wat]-cool$ motor v consid]ably1 ! total weight is n excessive4 ,:5 ! fuel is consid]$1 ! total weight is bel[ t ( ! rot>y :5 long flights are attempt$4 ,! radiator & wat] add complication & are a s\rce ( dang]4 ,! radiators increase ! head resi/ance & add v consid]ably to ! ma9t5ance co/4 ,illu/ration3 ,a ,motor ,in/allation 9 a ,pu%] ,type ,biplane1 ,%[+ ! ,motor at ! ,re> & ! ,d\ble ,radiator ,sections ,ov] ! ,body4 ,ea* type ( cool+ has its limitations1 & x is hop$ t an improvem5t 9 cool+ may be _h 9 ! ne> future4 ,?is sy/em %\ld prim>ily r$uce ! size & resi/ance ( ! p[] plant1 & if possible ! weight1 al?\gh ! latt] is a second>y consid]ation4 ,at pres5t ! cool+ sy/em prev5ts ev5 an approa* to ! true /reaml9e =m ( ! body4 99,propell] ,spe$994 ,= ! be/ results1 ! propell] spe$ %\ld n exce$ #abjj revolutions p] m9ute1 & = /ructural reasons ?is is g5]ally limit$ to #aejj ,r4 ,p4 ,m4 ,?is at once puts a limit+ value on ! output ( a giv5 size eng9e unless a ge> d[n arrangem5t is us$4 ,x %\ld be und]/ood1 betwe5 c]ta9 limits1 t ! p[] output increases r\ghly z ! spe$4 ,) direct drive arrangem5ts 9 :i* ! propell] is m\nt$ directly on ! end ( ! eng9e %aft1 ! motor revs4 are necess>ily ! propell] revs41 & ! only way ( increas+ ! spe$ is by increas+ ! l5g? ( ! /roke or by ge>+ d[n4 ,an increase 9 /roke adds rapidly to ! weight by increas+ ! cyl9d] l5g?1 l5g? ( connect+ rod1 l5g? ( crank ?r[s1 etc4 99,horsep[] ,rat+994 ,at pres5t !re are _m me?ods ( calculat+ ! horsep[] ( gasol9e eng9es4 ,=mula apply+ to auto or boat motors does n apply to flight conditions1 = ! a]o motor is ess5tially a high compression type & has a great] output p] unit ( displacem5t4 ,x is n practical to give ! rat$ horsep[] z ! maximum output possible "u ideal conditions1 = ?is w\ld give no idea z to ! practical capabilities except by long t$i\s calculation4 ,! brake horsep[] w\ld give no ov]load capacity at a fix$ propell] spe$1 & ! conditions are entirely diff]5t f ^? regulat+ ! rat+ ( auto motors4 ,! latt] c be =c$ up to ! wreck+ spe$1 or _m times ! normal automobile spe$ ( #cj miles p] h\r4 ,z a]o eng9es are g5]ally well kept up1 & well tun$ at all times1 ! rat$ horsep[] may be tak5 f #ae to #bj p] c5t bel[ t ( ! maximum brake horsep[]4 ,9 ge>$-d[n motors1 ! ge> effici5cy is /ill to be consid]$4 ,! "q ( ! quality ( ! mixture1 & b>ometric pressure1 also ent] into ! problem :e!r ! p[] is rat$ on ! maximum obta9$ ) a ri* mixture1 or is calculat$ f ! output at ! maximum effici5cy4 ,a writ] 9 ,aviation sugge/s t ! rat$ horsep[] be tak5 z #ie p] c5t ( ! p[] develop$ at a po9t midway betwe5 ! maximum output1 & ! output at ! greate/ effici5cy4 ,b>ometric pressure to be #cj in*es & ! revolutions #abjj4 ,ow+ to ! great div]sity 9 ! bore-/roke ratio1 a p[] =mula mu/ include ! bore & /roke4 ,?is makes ! ,s4,a4,e4 =mula = auto motors impossible4 ,a =mula is propos$ by a writ] 9 ,aviation4 ,! writ] has *eck$ ?is up ) ! publi%$ p]=mance ( sev]al well-kn[n a]onautical motors4 ,h ,b,,snr_/#ab1ejj ,:]e ,b bore 9 in*es1 ,s /roke 9 in*es1 ,n numb] ( cyl9d]s1 ,r ,crank%aft revolutions p] m9ute1 & ,h rat$ horsep[]4 ,?is applies only to ! f\r-/roke cycle type4 99,p[] & ,altitude994 ,! p[] drops (f rapidly ) an increase 9 altitude unless corrections are made = compression & mixture4 ,) con/ant volume1 ! decreas$ d5sity causes decreas$ compression4 ,z ! weight ( air tak5 9 p] /roke is r$uc$1 ?is also r$uces ! am\nt ( fuel t c be burn$ p] /roke4 ,by hold+ ! compression con/ant ?r\gh adju/m5t ( ! cle>ance or valve motion1 a fairly con/ant output c be _h ?r\gh a wide range ( altitudes4 ,a compression ( #aae p\nds p] squ>e in* 7commonly us$7 is difficult to h&le ) a light con/ruction1 b ?is pressure mu/ be obta9$ if ! output is to be kept )9 practical limits4 ,eng9es hav+ a compression ratio ( z high z #f are runn+ satisfactorily at sea level1 ?is ratio giv+ a mean effective work+ pressure ( #acd p\nds p] squ>e in*4 ,) ?is ratio ! eng9e _c be us$ ) full op5 ?rottle at sea level = m ?an #aj or #ae m9utes )\t caus+ damage to ! %aft1 be>+ & valves4 ,at ab\t #aj1jjj feet ! compression is normal4 ,at great altitudes c>buretion has become a great problem1 & z a]ial battles h already tak5 place at elevations ( #bj1jjj feet1 x is q possible t future motors w be equipp$ ) "s device t w =ce a measur$ fuel *>ge into ! cyl9d]s4 ,! air necess>y = ! combu/ion w also h to be pump$ 9 by "s means4 99,weight ,p] ,horsep[]994 ,! weight p] horsep[] ( ! eng9e is a v loose t]m s9ce s mu* dep5ds ^u ! equipm5t includ$ 9 ! weight4 ,z _m z #bj items may be consid]$ z be+ 9 ! d\btful li/1 & among ^! are ! radiator wat]1 pip+1 m\nt+1 propell] hub1 oil 9 sump1 wir+1 self-/>t]1 etc4 ,! only true unit weight is t obta9$ by tak+ ! plant complete 7ready to run71 ) ! cool+ sy/em1 gasol9e = an h\r's flight1 & ! oil4 ,! weight ( ! b>e eng9e signifies no?+4 ,! weights ( ! v>i\s items us$ on well kn[n motors are giv5 9 a table "u ! *apt] ,weight ,calculations4 ,:ile ! b>e weight ( a c]ta9 eng9e may be v l[ p] brake horsep[]1 an excessive fuel consumption w (t5 run ! effective weight up & ov] t ( a type 9 :i* ! b>e weight is f> great]4 ,! weight ( ! eng9e p] horsep[]1 includ+ ! magneto & c>buret]1 w run f #b4b to #e4j p\nds1 accord+ to ! type4 ,illu/ration3 ,two ,examples ( ,c[ls ,us$ ,ov] ,rot>y ,cyl9d] ,motors 7,air ,cool$74 99,fuel ,consumption994 ,! fuel consumption ( wat]-cool$ motors v>ies f #j4dh to #j4fe p\nds p] horsep[] h\r1 an av]age ( #j4f be+ safe4 ,! fuel consumption ( a rot>y air-cool$ motor w range f #j4f to #j4ge4 ,! oil consumption v>ies f #j4ah gallons p] horsep[] 9 ! air-cool$ type to #j4jce ) ! wat]-cool$ /ation>y motor4 99,radiators994 ,ow+ to extremes 9 ! temp]ature ( ! air at diff]5t altitudes1 ! radiat+ surface %\ld be divid$ into sections s t a con/ant cool+ effect c be obta9$ by v>y+ ! effective surface ( ! radiator4 ,! temp]ature c also be controll$ by an automatically regulat$ by-pass :i* %ort circuits a "p ( ! radiator wat] at l[ temp]atures4 ,con/ant wat] temp]ature has mu* to d ) ! effici5cy & g5]al op]ation ( ! motor1 & !re w be only "o temp]ature at :i* ! be/ results c be obta9$4 ,illu/ration3 ,typical ,radiators4 ,a7 ,side or ,top ,type4 ,illu/ration3 ,typical ,radiators4 7,b7 ,front ,type4 ,hunsak] f9ds t #j4hc squ>e feet ( actual cool+ surface p] horsep[] is correct at #fj ,m4 ,p4 ,h41 :ile o!rs give a value ( ab\t #ajj squ>e foot "u simil> conditions4 ,! front or project$ area v>ies ) ! ?ickness ( ! radiator1 ! ?icknesses v>y+ f #b to #e in*es4 ,! ,liv+/on radiator gives a cool+ surface ( #ej squ>e in*es p] squ>e in* ( front surface4 ,! total cool+ effect dep5ds ^u ! spe$1 ! location 9 reg>d to ! slip/ream1 & ! position on ! body4 ,a radiator mak] %\ld always be consult$ :5 mak+ ! f9al calculations4 ,see ,*apt] ,,xvi4 99,fuel ,tanks & ,pip+994 ,! fuel tanks may be ( copp]1 alum9um or t9-coat$ /eel1 & all jo9ts %\ld be weld$ or rivet$4 ,nev] dep5d ^u sold]1 z su* jo9ts soon op5 ?r\gh ! vibration ( ! eng9e4 ,gasol9e %\ld n come into contact ) /eel1 nor ! z9c us$ on galvaniz$ iron4 ,spla% plates are provid$ to keep ! fluid f surg+ back & =? :ile 9 flight4 ,all gas %\ld be suppli$ to ! eng9e ?r\gh a filt] or /ra9] plac$ 9 ! ma9 gas l9e4 ,! valves 9 ! fuel l9es %\ld be provid$ ) /opcocks1 s arrang$ t !y c be clos$ f ! pilot's seat4 ,9 g5]al1 ! c>buret]s %\ld be f$ by gravity f an ov]head s]vice tank1 ?is tank be+ suppli$ f ! ma9 res]voir by air pressure or a gasol9e pump4 ,! air c be compress$ by a pump on ! eng9e or by a paddle driv5 pump op]at$ by ! air/ream1 & z a rule ! latt] is pref]able1 z x c be op]at$ ) ! a]oplane glid+ & ) ! eng9e dead4 ,air pressure sy/ems are likely to fail ?r\gh leaks1 :ile ) a good gasol9e pump conditions are mu* m positive4 ,! gravity s]vice tank %\ld be locat$ s t x w fe$ correctly ) ! a]oplane tilt$ at lea/ #cj degrees f ! horizontal4 ,illu/ration3 ,two ,views ( ! ,monos\pape ,gnome ,rot>y ,cyl9d] ,motor4 ,?is ,motor ,has #i ,cyl9d]s ,arrang$ ,radially ,ar\nd ! ,crank%aft & ,develops #ajj ,horsep[]4 ,! ,cyl9d]s ,are ,air ,cool$4 ,! gasol9e pip+ %\ld be at lea/ #e_/af in* inside diamet]1 & %\ld be mo/ securely connect$ & support$ aga9/ vibration4 ,to gu>d aga9/ cry/allization at ! po9t ( atta*m5t1 special flexible rubb] hose is g5]ally us$4 ,?is mu/ be hose made specially = ?is purpose1 z ord9>y rubb] hose is soon dissolv$ or rott$ by gasol9e & oil4 ,air pockets mu/ be avoid$ at e po9t 9 ! fuel & oil sy/em4 ,illu/ration3 ,hall-,scott ,big ,six ,a]onautical ,motor ( ! ,v]tical ,wat]-cool$ ,type4 #abe ,horsep[]4 99,rotat+ ,cyl9d] ,motors994 ,! fir/ rotat+ cyl9d] motor 9 use 0 ! ,am]ican ,adams-,f>well1 a type t 0 soon foll[$ by ! bett] kn[n ,fr5* ,gnome4 ,o!r motors ( ?is type are ! ,cl]get1 ,le,rhone1 ,gyro & ,ob]eusel4 ,!y are all ( ! air-cool$ type--cool$ p>tly by ! revolution ( ! cyl9d]s ab\t ! crank-%aft1 & p>tly by ! propell] slip/ream4 ,:ile ! pi/ons slide ?r\gh ! cyl9d] bore1 ! rotat+ cyl9d] motor is n truly a reciprocat+ type1 z ! pi/ons d n move back & =? 9 reg>d to ! crank %aft4 ,! cyl9d]s revolve ab\t ! crank %aft z a c5t]1 :ile ! pi/ons & connect+ rods revolve ab\t ! crank p91 ! diff]5ce 9 ! pivot po9t caus+ relative1 b n actual1 reciprocation4 ,illu/ration3 ,hall-,scott #d-;,cyl9d] ,v]tical ,wat]-cool$ ,motor4 #hj-ij ,horsep[]4 ,! orig9al ,gnome motor drew 9 ! *>ge ?r\gh an inlet valve 9 ! pi/on head4 ,! gas pass$ f ! mix]1 ?r\gh ! holl[ crank-%aft1 & !n into ! crank-case4 ,! exhau/ valve 0 9 ! cyl9d] head4 ,?is valve arrangem5t 0 n entirely satisfactory1 & ! company develop$ ! ,monos\pape or ,s+le valve type4 ,! #ajj ,h4 ,p4 ,monos\pape ,gnome has #i cyl9d]s1 #d4c x #e4i4 ,! total weight is #bgb p\nds & ! unit weight is #b4gb p\nds p] horsep[]4 ,x op]ates on ! f\r-/roke cycle pr9ciple4 ,! gas consumption is #ab gals4 p] h\r1 & x uses #b4d gals4 ( ca/or oil4 ,! cyl9d]s & cool+ f9s are ma*9$ f a solid /eel =g+1 weigh+ #hh p\nds4 ,! f9i%$ cyl9d] weighs #e4e p\nds aft] ma*9+4 ,! walls are v ?91 probably ab\t #a_/af in*1 b !y /& up well "u s]vice conditions4 ,illu/ration3 ,/urtevant ,v ,type #h-;,cyl9d] ,wat] ,cool$ ,a]onautical ,motor4 ,?is ,motor ,is ,provid$ ,) a ,r$uction ,ge> ,%[n at ! ,re> ( ! ,crankcase4 ,assum+ ! pi/on to be on ! compression /roke1 ! ignition w occur f #ae to #bj be=e ! top dead c5t]4 ,mov+ d[n on ! work+ /roke1 & at #he f top dead c5t]1 ! exhau/ valve beg9s to op51 & ! exhau/ cont9ues until ! pi/on returns to ! upp] dead c5t]4 ,) ! valve /ill op51 pure air n[ beg9s to ent] ?r\gh ! exhau/ valve & cont9ues to fl[ until ! valve closes at #fe bel[ ! bottom c5t]4 ,/ill desc5d+1 ! pi/on =ms a p>tial vacuum 9 ! cyl9d]1 until at #b be=e ! l[] c5t] ! pi/on op5s ! ports & a v ri* mixture is drawn 9 f ! crank case4 ,?is ri* mixture is dilut$ to ! prop] d5sity by ! air already 9 ! cyl9d]1 & =ms a combu/ible gas4 ,! upw>d movem5t ( ! pi/on on ! compression /roke closes ! ports & compression beg9s4 ,! mixture ent]s ! crank case ?r\gh a holl[ %aft1 ) ! fuel jets ne> ! crank ?r[s4 ,a tim$ fuel pump injects ! fuel at ! prop] int]vals4 ,illu/ration3 ,dus5b]g #d-;,cyl9d] ,v]tical ,wat] ,cool$ ,motor ,) ,r$uction ,ge>4 ,f\r ,valves ,are ,us$ ,p] ,cyl9d]4 ,note ,peculi> ,valve ,motion4 99,curtiss ,motors994 ,! ,curtiss motors are ( ! wat]-cool$ ,v type1 ) #f to #h cyl9d]s p] r[4 ,^! are probably ! be/ kn[n motors 9 ,am]ica & are ! result ( ye>s ( developm5t1 z ,curtiss 0 ! fir/ to manufacture a]o motors on a practical scale4 ,illu/ration3 ,curtiss ,type ,,ox-#e ,eight ,cyl9d] ,a]oplane ,motor 99,hall-,scott ,motors994 ,^! motors are made by "o ( ! pione] a]onautical motor build]s1 & h met ) great favor4 ,!y are ( ! v]tical wat]-cool$ type1 & ) ! exception ( m9or details & weight are v simil> 9 ext]nal appe>ance to ! automobile motor4 ,f\r & #f-;cyl9d] types are built4 99,/urtevant ,motors994 ,^! are ( ! ,v wat]-cool$ type1 & are provid$ ) or )\t a r$uc+ ge>4 ,at lea/ "o model is provid$ ) l9$ alum9um cyl9d]s4 99,dus5b]g ,motor994 ,?is is a f\r-cyl9d]1 wat]-cool$1 v]tical motor ) a v peculi> valve motion4 ,! valves are op]at$ by long lev]s ext5d+ f ! cam%aft4 ,two inlet1 & two exhau/ valves1 are us$ p] cyl9d]4 ,! motor is g5]ally furni%$ ) a r$uc+ ge>4 99,rob]ts ,motor994 ,?is is a solit>y example ( ! two-/roke cycle type1 & has be5 us$ = _m ye>s4 ,x is simple & compact1 & is notewor?y = ! simplicity ( its oil+ sy/em4 ,! oil is mix$ ) ! gasol9e1 & is f$ ?r\gh ! c>buret]4 ,?is is "o ( ! _m advantages ( a two-/roke cycle motor4 99,table ( ,a]onautical ,motors994 ,! foll[+ table w give an idea z to ! g5]al dim5sions ( ,am]ican a]onautical motors3 99,! ,lib]ty ,motor994 ,! necessity ( spe$ & quantity 9 ! production ( a]onautical motors aft] ! decl>ation ( w> caus$ ! ,gov]nm5t to s]i\sly consid] ! design ( a highly /&>diz$ motor4 ,?is idea 0 fur!r develop$ 9 a conf]5ce ) repres5tatives ( ! ,fr5* & ,briti% missions on ,may #bh1 #aiag1 & 0 !n submitt$ 9 ! =m ( sket*es at a jo9t meet+ ( our allies1 ! ,aircraft ,production ,bo>d1 & ! ,jo9t ,army & ,navy ,te*nical ,bo>d4 ,! spe$ ) :i* ! "w 0 pu%$ is rem>kable1 = on ,july #crd1 ! fir/ model ( ! eight cyl9d] type 0 deliv]$ to ! ,bureau ( ,/&>ds4 ,"w 0 !n conc5trat$ on ! #ab cyl9d] model1 & "o ( ! exp]im5tal eng9es pass$ ! #ej h\r te/ ,augu/ #be1 #aiag4 ,x is ( ! ,v type ) ! cyl9d] blocks at an angle ( #de degrees in/ead ( #fj degrees z 9 ! majority ( #ab cyl9d] ,v motors4 ,?is makes ! motor mu* n>r[] & m suitable = in/allation 9 ! fuselage1 & 9 ?is respect is simil> to ! arrangem5t ( ! old ,pack>d aviation motor4 ,x has ! additional advantages ( /r5g!n+ ! crank case4 ,! bore & /roke is #e x #g z 9 ! ,hall-,scott models ,a-#e & ,a-#g4 ,! cyl9d]s comb9e ! lead+ features ( ! ,g]man ,m]c$es1 ! ,engli% ,rolls-,royce1 ,lorra9e-,dietri*1 & ,isotta-,fras*9i4 ,/eel cyl9d] walls are us$ ) press$ /eel wat] jackets1 ! latt] be+ appli$ by means ( a me?od develop$ by ! ,pack>d ,company4 ,! valve cages are drop =g+s1 weld$ to ! cyl9d] heads4 ,! cam%aft & valve ge> are above ! cyl9d] head z 9 ! ,m]c$es1 b ! lubrication ( ! p>ts 0 improv$ ^u by ! ,pack>d ,company4 ,! crank%aft foll[s /&>d #ab cyl9d] practice except z to ! oil+ sy/em1 ! latt] foll[+ ,g]man practice r closely4 ,! fir/ sy/em us$ "o pump to keep ! crankcase empty deliv]+ ! oil to an outside res]voir4 ,a second pump took ! oil f ! res]voir & deliv]$ x to ! ma9 crank%aft be>+s "u pressure4 ,! ov]fl[ f ! ma9 be>+s travel$ out ov] ! face ( ! crank ?r[ *eeks to a ,scupp]1 :i* collect$ ! excess = crank p9 lubrication4 ,9 ! pres5t sy/em1 a simil> g5]al me?od is foll[$ except t ! pressure oil is n only f$ to ! ma9 crank%aft be>+s1 b also ?r\gh holes 9 ! crank *eeks to ! crank p9s in/ead ( by ! =m] scupp] fe$4 ,a special ,z5i? c>buretor is us$1 t is p>ticul>ly adapt$ to ! ,lib]ty motor4 ,a ,delco ignition sy/em ( special =m is in/all$ to meet ! peculi> cyl9d] block angle ( #de degrees4 ,?is ignition is ( ! electric g5]ator type & magnetos are n us$4 ,sev]al ,am]ican records h be5 brok5 by ! new motor1 & x is report$ to h giv5 v satisfactory s]vice1 b full details ( ! p]=mance are difficult to obta9 ow+ to ! /rict c5sor%ip ma9ta9$ 9 reg>d to ?+s a]onautic4 ,! motor is p>ticul>ly well adapt$ to heavy bomb+ & reconnaissance type ma*9es1 or = heavy duty4 ,x is report$ t ! use ( ! motor has be5 discont9u$ on spe$ sc\ts1 al?\gh fur!r developm5ts along ?is l9e may n h be5 report$4 ,! foll[+ gives ! pr9cipal *>act]i/ics ( ! ,lib]ty motor1 issu$ by ! ,national ,advisory ,committee = ,a]onautics4 ,ye> ,horse-p[] ,weight ,weight ,p] ,gasol9e ,h4 ,p4 7,model7 ,p\nds ,h4 ,p4 ,h\r #aiag #djj #hja #b4jj #j4ej #aiah #dcb #hjh #a4ij #j4dh #aiah #dej #hbe #a4hj #j4df ,! motors li/$ are all #ab cyl9d] models1 & ! output & unit weights are bas$ on a crank-%aft spe$ ( #ahjj ,r4 ,p4 ,m4 ,! #e x #g bore & /roke give an output ( #cg4e horsep[] p] cyl9d] 9 ! late/ model4 ,9 #aiag1 ! ,lib]ty motor 0 #fe p] c5t m p[]ful1 & #bh p] c5t light]1 ?an ! av]age /ock motor 9 s]vice dur+ t ye>4 ,,*apt] ,,xxi4 ,,gloss>y ,,( ,,a]onautical ,,words4 ,9 ! foll[+ li/ are ! mo/ common ( ! a]onautical words & phrases4 ,_m ( ^! words are ( ,fr5* orig91 & 9 su* cases are m>k$ ,fr4 ,9 cases ( ,engli% words1 ! ,fr5* equival5ts foll[ 9 p>5!ses4 ,:5 a ,fr5* ^w or t]m is giv5 x is 9 italics1 unless x is 9 common use 9 ?is c\ntry4 ,words m>k$ 7997 are ! revisions adopt$ by ! ,national ,advisory ,bo>d ( ,a]onautics at ,wa%+ton1 ,d4 ,c41 & include ! t]m ,airplane1 :i* 0 int5d$ to supplant ! m common ,a]oplane4 ,^! revisions h n met ) univ]sal adoption1 = ! old] words are too well e/abli%$ to admit ( *ange4 ,a ,,absolute ,,units4 ,units giv5 9 t]ms ( mass4 ,= expression 9 t]ms ( p\nds 7,gravitational units7 !y mu/ be multipli$ by "s factor involv+ ! value ( gravitation4 ,?us1 to conv]t units ( mass into p\nds1 ! mass mu/ be multipli$ by ! value ( gravitation1 #cb4af be+ ! av]age figure tak5 = ?is quantity4 ,to conv]t ! absolute lift factors giv5 by ! ,n4,p4,l4 into p\nds p] squ>e foot p] mile p] h\r1 multiply ! absolute value by ,o4#jje;,,iv4 ,,absolute ,,z]o4 ,! temp]ature at :i* heat ceases to exi/4 ,?is is #dfa degrees bel[ ! ,fahr5heit z]o1 or #bgc degrees bel[ ! ,c5tigrade z]o4 ,,accel]ate4 ,to increase 9 spe$4 ,,aci] 7,fr47 ,/eel4 ,,a]odonetics4 ,a ^w orig9at$ by ,lan*e/] to d5ote ! sci5ce ( /ability4 ,,a]ocurve4 ,see ,,a](oil4 ,,a](oil499 ,a ?9 w+-l /ructure design$ to obta9 lift by ! reaction ( mov+ air ^u its surfaces4 ,,a]odynamics4 ,a sci5ce inve/igat+ ! =ces produc$ by a /ream ( air act+ ^u a surface4 ,,a]odynamic ,,resi/ance4 ,! resi/ance caus$ by turbul5ce or eddies4 ,,a]odrome4 ,a fly+ field4 ,?is ^w 0 also us$ by ,langley to describe an a]oplane4 ,,a]o/at4 ,a light] ?an air ma*9e4 ,,a]o/atics4 ,! sci5ce ( light] ?an air ma*9es1 or devices su/a9$ by flotation4 ,,a]oplane4 7,fr4 ,l',avion47 ,a heavi] ?an air craft su/a9$ by fix$ w+ surfaces driv5 ?r\gh ! air at ! same velocity z ! body ( ! ma*9e4 ,auxili>y surfaces are provid$ = /abiliz+1 /e]+1 & = produc+ *anges 9 ! altitude4 ,! l&+ ge> may be suitable = ei!r l& or wat]1 al?\gh 9 ! latt] case x is g5]ally kn[n z a ,seaplane4 ,! ,committee equival5t is ,airplane4 ,,ail]on499 ,a movable auxili>y surface us$ 9 ma9ta9+ lat]al balance4 ,,aile 7,fr47 ,w+4 ,,airboat4 ,an a]oplane provid$ ) a light boat hull 9 :i* ! pilot & pass5g] are enclos$4 ,,aircraft499 ,any =m ( craft design$ = ! navigation ( ! air4 ,?is includes a]oplanes1 balloons1 dirigibles1 helicopt]s1 orni?opt]s1 etc4 ,,airplane499 ,see a]oplane4 ,,air%ip4 ,a light] ?an air craft provid$ ) means ( propulsion4 ,,air-,,screw4 ,see ,,propell]4 ,,altimet]499 ,an in/rum5t us$ = det]m9+ ! height ( aircraft above ! e>?4 ,,altitude4 ,height ( aircraft above sea level--g5]ally giv5 9 feet4 ,,amphibian4 ,an a]oplane equipp$ ) l&+ ge> = bo? l& & wat]4 ,,anemomet]499 ,an in/rum5t = measur+ ! velocity ( ! w9d4 ,,angle ,,( ,,incid5ce4 ,! angle made by a surface or body ) an air /ream4 ,9 ! case ( curv$ w+s1 ! angle is measur$ f ! *ord ( ! curve4 ,,angle ,,( ,,attack499 ,see ,angle ( ,incid5ce4 ,,angle ,,( ,,entry4 ,! angle made ) ! *ord ( a w+ section by a l9e drawn tang5t to ! upp] curv$ face1 & at ! front edge4 ,,angle ,,( ,,trail4 ,! angle made by a l9e drawn tang5t to ! upp] surface at ! trail+ edge4 ,,anemograph4 ,an in/rum5t us$ = graphically record+ ! velocity ( air curr5ts4 ,,apt]oid ,,aspect4 ,a w+ is 9 apt]oid aspect :5 ! n>r[ edge is t[>d ! w9d4 ,,areti] ,,arri]e 7,fr47 ,see ,trail+ ,edge4 ,,areti] ,,avant 7,fr47 ,see ,lead+ ,edge4 ,,arbre 7,fr47 ,%aft4 ,,aspect ,,ratio499 ,! ratio ( ! w+ span to ! *ord 7l5g? divid$ by wid?74 ,,att]rissage 7,fr47 ,l&+ ,ge>4 ,,atta*es 7,fr47 ,fa/5+s4 ,,auxili>y ,,surface4 ,a surface us$ = /ability or = ! control ( ! a]oplane4 ,,aviaphone4 ,an electric sy/em ( communication betwe5 ! pass5g] & pilot4 ,,avion 7,fr47 ,see ,a]oplane4 ,,axis ,,( ,,pit*4 ,! axis tak5 p>allel to ! l5g? ( ! w+s1 & ?r\gh ! c5t] ( gravity4 ,?is is sometimes call$ ! ,y axis4 ,,axis ,,( ,,roll4 ,an axis pass+ =e & aft p>allel to ! c5t] l9e ( ! propell]4 ,?is axis is sometimes call$ ! ,x axis4 ,,axis ,,( ,,yaw4 ,a v]tical axis1 pass+ ?r\gh ! c5t] ( gravity1 ar\nd :i* ! ma*9e sw+s :5 be+ /e]$ 9 a horizontal direction "u ! action ( ! rudd]4 ,?is is ! ,z axis4 ,b ,,balsa ,,wood4 ,a v light wood obta9$ f ,s\? ,am]ica4 ,x is light] ?an cork4 ,,balloon499 ,a =m ( aircraft ( ! light] ?an air type compris+ a gas bag & c>4 ,x is n provid$ ) a p[] plant1 & dep5ds ^u ! buoyancy ( ! gas = its su/5tation4 ,a balloon re/ra9$ f free flight by means ( a cable is kn[n z a ,captive balloon4 ,a kite balloon is an elongat$ =m ( captive balloon1 fitt$ ) a tail to keep x head$ into ! w9d1 & is incl9$ at an angle s t ! w9d aids 9 increas+ ! lift ( ! gas4 ,,ballonet499 ,a small air balloon )9 ! ma9 gas bag ( a balloon or dirigible us$ = controll+ ! asc5t or desc5t1 & = keep+ ! fabric ( ! out] envelope taut :5 ! pressure ( ! gas is r$uc$4 ,! ballonet is kept inflat$ ) air at ! requir$ pressure1 ! air be+ controll$ by a valve or by regulat+ ! spe$ ( ! bl[]4 ,,bank499 ,to incl9e ! w+s lat]ally :5 mak+ a turn s t a portion ( ! lift =ce w be oppos$ to ! c5trifugal =ce4 ,,b>ograph499 7,fr4 ,b>ographe47 ,an in/rum5t us$ = record+ pressure v>iations 9 ! atmosph]e4 ,! pap] *>ts on :i* ! records are made are us$ = det]m9+ ! altitude ( aircraft4 ,,b>omet]4 ,an in/rum5t us$ = measur+ v>iations 9 ! atmosph]ic pressure1 b is n provid$ ) a record+ me*anism z 9 ! case ( ! b>ograph4 ,,beaume4 ,a scale ( d5sity or a hydromet] unit us$ 9 measur+ ! d5sity ( fluids4 ,on ! ,beaume scale wat] is #aj4jj1 :ile on ! ,specific gravity scale wat] is #a4jj4 ,! ,beaume scale is g5]ally us$ = gasol9e & oils4 ,,b5d+-,,mom5t4 ,! mom5t or ,lev]age t t5ds to b5d a beam4 ,,bequille 7,fr47 ,tail ,skid4 ,,b]ceau de ,,moteur 7,fr47 ,eng9e ,b$4 ,,bias ,,laid ,,fabric4 ,fabric laid on ! w+ /ructure ) ! seams at an angle ) ! ribs4 ,,biplace 7,fr47 ,two ,seat]4 ,,biplane499 7,fr4 ,biplan47 ,an a]oplane ) two sup]pos$ lift+ surfaces4 ,,body4 ,see ,,fuselage4 ,,body ,,rails4 ,see ,,long]ons4 ,,bois 7,fr47 ,wood4 ,,bois ,,creus 7,fr47 ,holl[ wood con/ruction4 ,,bomb]4 ,an a]oplane us$ = bomb+ op]ations4 ,,boom4 ,! =e & aft beams runn+ f ! w+s to ! tail 9 a pu%] type biplane4 ,,bord de ,,attacque 7,fr47 ,ent]+ or lead+ edge4 ,,bord de ,,sortie 7,fr47 ,trail+ edge4 ,,blade1 ,,propell]4 7,fr4 ,pale-,helice47 ,,b\lon 7,fr47 ,bolt4 ,,b\ssole 7,fr47 ,compass4 ,,bras de ,,aile 7,fr47 ,w+ ,sp>4 ,,brevet 7,fr47 ,fly+ p]mit or lic5se4 ,,brakes1 ,,air4 ,small adju/able flaps us$ 9 increas+ ! head resi/ance dur+ a l&+1 ?us decreas+ ! spe$4 ,,burble ,,po9t4 ,! angle at :i* ! lift ( a w+ section rea*es a maximum4 ,,buoyancy4 ,! /atic =ce due to a diff]5ce 9 d5sity4 ,! diff]5ce 9 d5sity betwe5 ! gas 9 a balloon envelope & ! outside air det]m9es ! su/a9+ or buoyant =ce ( a balloon4 ,,bus4 ,a sl[ fairly /able a]oplane us$ 9 tra9+ s*ools4 ,c ,,cable4 7,fr4 ,cable47 ,a wire rope built up ( a numb] ( small /r&s4 ,,cabre'4 99 7,fr47 ,a fly+ attitude 9 :i* ! angle ( incid5ce is l>g] ?an normal ) ! tail well d[n4 ,,camb]499 ,! convexity1 or rise ( a lift+ surface1 measur$ f ! *ord ( ! curve4 ,x is usually giv5 z ! ratio ( ! maximum height ( ! curve to ! l5g? ( ! *ord4 ,top camb] ref]s to ! upp] surface1 & bottom camb] to ! l[] surface4 ,,cabane 7,fr47 ,! c5t] /ruts ris+ f ! top ( ! body to ! upp] w+1 or ! %ort /ruts us$ = ! brac+ ( ! ov]hang+ portions ( a biplane w+4 ,usually cabane d5otes ! c5t] cell /ruts4 ,,can>d 7,fr47 ,a ma*9e 9 :i* ! elevator & /abiliz] are 9 front4 ,! can>d type flies ,tail fir/4 ,,capot 7,fr47 ,c[l or motor hood4 ,,captive ,,balloon499 ,see ,balloon4 ,,capacity499 ,! lift+ capacity is ! maximum fly+ load ( an aircraft4 ,! c>ry+ capacity 7live load7 is ! excess ( ! lift+ capacity ov] ! dead weight ( ! a]oplane1 ! latt] includ+ ! /ructure1 p[] plant & ess5tial accessories4 ,,c>l+ue 7,fr47 ,cock-pit4 ,,cata-,,h$ral4 ,a negative dih$ral1 or w+ arrangem5t1 :]e ! w+ tips are l[] ?an ! c5t] portion4 ,,catapult4 ,a device = laun*+ an a]oplane f ! deck ( a %ip or o!r limit$ space4 ,! fir/ ,wright ma*9es 7 laun*$ ) a catapult4 ,,cell4 7,fr4 ,cellule47 ,! space includ$ betwe5 adjac5t /ruts ( a biplane4 ,! space betwe5 ! c5t] /ruts is ! ,c5t] ,cell4 ,,ceil+4 ,! maximum altitude to :i* an a]oplane c asc5d4 ,,ce9ture de ,,surete 7,fr47 ,safety ,belt4 ,,c5t] ,,( ,,pressure 7,c4 ,p4799 ,! po9t ( application ( ! resultant ( all a]odynamic =ces on an a]oplane w+4 ,if ! w+ is support$ at ! c5t] ( pressure x w be 9 equilibrium4 ,,c5t] ,,( ,,gravity4 ,! po9t at :i* an a]oplane w balance :5 freely susp5d$4 ,,c5t] ,,( ,,buoyancy499 ,! po9t at :i* ! resultant ( all ! buoyant =ces act4 ,,*>ni]e 7,fr47 ,h+e4 ,,*assis4 ,! l&+ :eels & _! frame4 ,?is is also call$ ! ,l&+ ge> 9 ,engli%1 or ! ,tra9 de ,att]rissage 9 ,fr5*4 ,! *assis c>ries ! load :5 re/+ on ! gr\nd or :5 runn+ ov] ! surface4 ,,*ord499 ,?is has two mean+s4 ,! *ord is ! wid? ( a w+ or its %orte/ dim5sion4 ,! *ord is also ! /raight l9e drawn across ! lead+ & trail+ edges ( a w+ section4 ,,*as]4 7,fr4 ,avion de ,*asse47 ,a small1 fa/ ma*9e us$ 9 sc\t+ or fight+4 ,?is type is also kn[n z a ,spe$ sc\t4 ,,*>a-,a-,,banc 7,fr47 ,a two seat] a]oplane 9 :i* ! pilot & pass5g] are seat$ side by side4 ,,clo*e 7,fr47 ,a type ( control column us$ on ! old ,type ,,xi ,bl]iot4 ,,cock-,,pit4 ,! "p ( ! body occupi$ by ! pilot or pass5g]4 ,! op5+s 9 ! body cut = entrance & exit are ! ,cock-pit ,op5+s4 ,,comm&es ,a ,,pont 7,fr47 ,control bridge or ,dep]duss9 yoke4 ,,compte ,,t\rs 7,fr47 ,ta*omet] or spe$ indicator4 ,,compon5ts4 ,! individual =ces t make up a total resultant =ce4 ,,controls499 7,fr4 ,comm&es47 ,! complete sy/em us$ = /e]+1 elevat+1 balanc+1 & spe$ regulation4 ,:5 controls are op]at$ by h& !y are kn[n z ,manual ,controls4 ,,control ,,bridge4 7,fr4 ,comm&es ,a ,pont47 ,! ,u %ap$ lev] us$ ) ! ,dep]duss9 control sy/em4 ,sometimes kn[n z ! ,yoke4 ,,control ,,/ick4 7,fr4 ,man*e ,a ,balai47 ,a simple control lev] capable ( be+ mov$ 9 f\r directions = elevation1 depression & lat]al balance4 ,,control ,,surfaces4 ,! adju/able surfaces us$ = direct+ & balanc+ aircraft4 ,on an a]oplane ^! are repres5t$ by ! rudd]1 elevator1 & ail]ons4 ,,contreplaque 7,fr47 ,?ree-ply wood4 ,,corde 7,fr47 ,cord or wire4 ,,cord ,a ,,piano 7,fr47 ,piano or solid h>d wire4 ,,cord ,,w9d+4 7,fr4 ,transfil47 ,a w9d+ wrapp$ ar\nd wood5 /ruts to prev5t spl9t]+ or complete fracture4 ,,cosse 7,fr47 ,?imble = cable connections4 ,,c\ss ,,9 7,fr47 ,cu%ion4 ,,cov]+1 ,,w+4 7,fr4 ,entoilage47 ,! fabric us$ 9 cov]+ ! w+ /ructure4 ,,critical ,,angle499 ,! angle ( attack or incid5ce at :i* ! lift is a maximum4 ,,c[l4 7,fr4 ,capot47 ,! metal cov] surr\nd+ a rot>y cyl9d] motor4 ,,croisillons 7,fr47 ,brac+ wires4 ,d ,,damp+4 ,! r$uction ( oscillation or vibration by ! resi/ance ( ! /abiliz+ surfaces4 ,,dead ,,load4 ,! weight ( ! /ructure1 p[] plant1 & ess5tial accessories4 ,,dead ,,wat]4 ,! wake directly 9 ! re> ( a mov+ body or surface4 ,de ,,*asse 7,fr47 ,see ,,*as]4 ,,decalage499 ,! diff]5ce 9 ! angle ( incid5ce betwe5 ! upp] & l[] w+s ( a biplane4 ,,demoiselle ,,type4 ,a small monoplane type develop$ by ,santos ,dumont4 ,,d5sity4 ,! specific weight1 or ! weight p] cubic foot4 ,,di$re 7,fr47 ,dih$ral angle4 ,,d]ive 7,fr47 ,f94 ,,dih$ral ,,angle4 7,fr4 ,di$re47 ,:5 ! tips ( ! w+ are high] ?an at ! c5t]1 ! two w+ halves =m an angle4 ,! includ$ angle betwe5 ! two halves1 tak5 above ! surface1 is kn[n z ! ,dih$ral angle4 ,,dipp+ ,,front ,,edge4 ,a w+ section 9 :i* ! lead+ edge is well b5t d[n bel[ ! re/ ( ! l[] surface4 ,,dirigible499 ,a light] ?an air craft 9 :i* su/5tation is provid$ by a gas bag4 ,x diff]s f a balloon 9 hav+ a p[] plant1 & is ?us capable ( fly+ 9 any desir$ direction reg>dless ( ! w9d4 ,,disc ,,area ,,( ,,propell]499 ,! total area ( ! disc swept out by ! propell] tips4 ,,discont9uity4 ,int]ruption 9 direction1 or breaks 9 /ream l9e fl[4 ,a body caus+ eddies or turbul5ce causes ,discont9u\s fl[4 ,! surface sep>at+ ! eddies & ! cont9u\s /ream is call$ a ,surface ( ,discont9uity4 ,,displacem5t4 ,! volume or space occupi$ by a float+ body4 ,,d\ble ,,camb]4 ,a w+ section 9 :i* bo? ! top & bottom surfaces are giv5 a convex camb] or curvature4 ,,dope4 7,fr4 ,enduit47 ,a solution us$ = protect+ & /ret*+ ! w+ fabric4 ,,drag4 ,! resi/ance (f]$ to ! =w>d motion ( a surface or body mov+ ?r\gh ! air4 ,z def9$ by ! ,advisory ,committee ?is is ! total resi/ance (f]$ by ! craft & includes bo? ! resi/ance ( ! w+s & body4 ,?is conception is confus+1 h5ce ! au?or has consid]$ drag z be+ ! =w>d resi/ance ( ! w+s alone4 ,! resi/ance ( ! /ructure is simply call$ ! ,head resi/ance1 & ! sum ( ! resi/ances is ! ,total resi/ance4 ,?is nom5clature 0 9 exi/5ce be=e ! ,advisory ,bo>d propos$ _! def9ition4 ,,drift4 ,z def9$ by ! ,advisory ,bo>d1 ! drift is ! horizontal resi/ance (f]$ by ! w+s alone4 ,?is is confus+ s9ce previ\s works def9$ ,drift z ! am\nt by :i* an aircraft 0 driv5 out ( its normal pa? by w9d gu/s4 ,accord+ to usage1 ,drift is ! sidewise deviation f ! normal flight pa?4 ,,drag ,,wires4 ,! brac+ wires us$ = resi/+ ! drag /resses set up 9 ! w+4 ,,drift ,,indicator4 ,an in/rum5t = indicat+ ! am\nt by :i* an aircraft is bl[n out ( its pa? by side w9ds4 ,,dual ,,control4 ,a d\ble sy/em ( control t c be op]at$ bo? by ! pilot & pass5g]4 ,,dut* ,,roll4 ,a comb9$ side roll & =e & aft pit*4 ,! ma*9e rolls f side to side 9 comb9ation ) an up & d[n motion ( ! nose4 ,,dynamic ,,pressure4 ,! pressure due to ! impact ( an air /ream4 ,e ,,ecc5tric ,,load4 ,a load act+ to "o side ( ! c5t] l9e ( a beam or /rut4 ,,ecole 7,fr47 ,s*ool4 ,,ecr\ 7,fr47 ,nut4 ,,eddy4 ,an irregul>ly mov+ mass ( air caus$ by ! break+ up ( a cont9u\s air /ream1 or by ,discont9uity4 ,,effici5cy4 ,! effici5cy ( a lift+ surface is g5]ally express$ by ! ratio ( ! lift to ! drag1 or ! ,lift-drag ratio4 ,! effici5cy ( a propell] is ! ratio ( ! "w usefully appli$ to ! air /ream 9 reg>d to ! p[] suppli$ to ! propell]4 ,,elevator499 ,! h+$ horizontal tail surface us$ = ma9ta9+ longitud9al equilibrium & = asc5t or desc5t4 ,,emp5nage 7,fr47 ,! gr\p ( tail surfaces1 includ+ ! elevator & /abiliz]4 ,,enduit 7,fr47 ,dope4 ,,eng9e ,,rotation4 ,accord+ to ! ,advisory ,bo>d1 an eng9e is turn+ 9 "r-h& rotation :5 ! output %aft /ub is turn+ anti-clockwise4 ,,eng9e ,,be>]s 7,,b$74 7,fr4 ,b]ceau du ,moteur74 ,! timb]s or fuselage memb]s ^u :i* ! eng9e is fa/5$4 ,,eng9e ,,spid] or ,,bracket4 7,fr4 ,arraignee ,support de ,moteur47 ,a p]=at$ metal support = a rot>y cyl9d] motor4 ,,ent]+ ,,edge4 7,fr4 ,bord ,d',attaque or ,areti] ,avant47 ,! front edge1 or air engag+ edge1 ( an a](oil or lift+ surface4 ,x is also call$ ! ,lead+ ,edge4 ,,entoilage 7,fr47 ,w+ fabric or cov]+4 ,,envelope4 ,! gas bag ( a balloon or dirigible4 ,,essieu 7,fr47 ,axle4 ,,env]gure 7,fr47 ,w+ span4 ,,exp&+ ,,pit*4 ,a sy/em 9 :i* ! pit* increases or exp&s t[>ds ! tips ( ! propell]4 ,f ,,fabric1 ,,w+4 7,fr4 ,entoilage47 ,! clo? us$ = cov]+ ! w+ & control surface /ructures4 ,,fair+4 7,fr4 ,fusele47 ,wood cov]+s us$ to /reaml9e /eel /ruts or o!r /ructural memb]s4 ,,f]rules4 ,%eet /eel caps us$ = ! ends ( ! int]plane ,/ruts4 ,,f94 7,fr4 ,d]ive47 ,a fix$ v]tical /abiliz+ surface us$ = damp+ out horizontal vibration & oscillations4 ,,f95ess ,,ratio4 ,! ratio ( ! maximum l5g? to ! wid? ( a /reaml9e body4 ,,fitt+s4 7,fr4 ,f]rures1 ,godets47 ,! metal p>ts us$ = mak+ connections betwe5 ! /ructural p>ts ( an a]oplane4 ,,fix$ ,,tail4 7,see ,,/abiliz]47 ,,flaccid ,,blade ,,propell]4 ,a propell] hav+ a clo? cov]$ frame "w on :i* ! fabric is free to adju/ itself to ! air pressure4 ,,flaps1 ,,elevator4 7,fr4 ,volets de ,pr(ondeur47 ,see ,,elevator4 ,,flexible ,,%aft4 7,fr4 ,transmission flexible47 ,us$ = ta*omet] drive4 ,,floor+4 7,fr4 ,plan*]47 ,,flasque ,d',,helice 7,fr47 ,propell] flange4 ,,foot ,,lev]4 7,fr4 ,palomni]47 ,! foot lev] g5]ally us$ to op]ate ! rudd]4 ,,=m]s4 ,supports us$ 9 giv+ a c]ta9 outl9e to ! fuselage4 ,! =m]s are atta*$ to ! fuselage frame & 9 turn support small /r+]s on :i* ! fabric is fa/5$4 ,,frictional ,,wake4 ,! foll[+ curr5t ( air 9 ! re> ( a mov+ body or surface4 ,because ( ! friction1 a portion ( ! air is drawn 9 ! direction ( ! motion4 ,,fuselage4 ,a /ructure1 usually enclos$1 :i* conta9s & /reaml9es ! p[] plant1 pass5g]s1 fuel1 etc4 ,sometimes call$ ! ,body4 ,,fuselage ,,biplane4 ,see ,,tractor ,,biplane4 ,,fusi=m4 ,( /reaml9e =m4 ,g ,,gap4 ,! v]tical di/ance betwe5 lead+ edges ( ! sup]pos$ planes ( ! biplane or triplane4 ,,glid+4 7,fr4 ,vol ,plan47 ,) an a]oplane ! weight ( ! ma*9e c be made to provide a =w>d compon5t t w all[ ! ma*9e to desc5d sl[ly 7)\t p[]7 along an incl9$ l9e4 ,?is l9e is kn[n z ! ,glid+ ,pa?4 ,,glid+ ,,angle4 ,! angle made by ! glid+ pa? ) ! horizontal is kn[n z ! glid+ angle4 ,?is may be express$ 9 degrees or 9 ! units ( horizontal di/ance travel$ p] foot ( fall4 ,,glid]4 ,a small =m ( a]oplane )\t a p[] plant1 :i* is capable ( glid+ d[n f an elevation 9 ! mann] ( an a]oplane4 ,) a prop] direction & velocity ( w9d x c be made to hold a con/ant altitude & c be made to hov] ov] "o spot cont9u\sly4 ,,g\v]nail 7,fr47 ,rudd]4 ,,guy ,,wire4 ,a brac+ wire4 ,h ,,h>d ,,wire4 ,a solid temp]$ wire ( high t5sile /r5g? us$ = a]oplane brac+ sy/ems4 ,h4,t4 ,,wire4 ,ano!r expression = h>d or high t5sile /r5g? wire4 ,,head ,,resi/ance4 ,! resi/ance ( ! /ructural p>ts ( an aircraft4 ,9 an a]oplane1 ! head resi/ance is ! sum ( ! resi/ances ( ! body1 /ays1 /ruts1 *assis1 tail1 rudd]1 elevators1 etc42 9 fact1 ?is includes ev]y?+ ) ! exception ( ! w+ drag4 ,,helicopt]4 ,a type ( direct lift ma*9e 9 :i* su/5tation is p]=m$ by v]tical air screws or propell]s4 ,,helix4 ,a geometrical curve =m$ by ! comb9$ advance & revolution ( a po9t4 ,,helice 7,fr47 ,propell] or screw4 ,,helice ,,tractive 7,fr47 ,tractor propell]4 ,,hydroa]oplane4 ,see ,,seaplane4 ,,holl[ ,,wood ,,con/ruction4 7,fr4 ,bois ,creus47 ,,hood ,,( ,,eng9e4 7,fr4 ,capot47 ,,hydromet]4 ,an in/rum5t = measur+ ! d5sity ( liquids4 ,i ,,ic?yoid4 ,fi% or /ream l9$ %ape4 ,,incl9$ ,,plane4 ,a plane incl9$ to ! w9d /ream s t ! en]gy ( ! air /ream is brok5 up into ! two compon5ts ( lift & drag4 ,,incl9omet]4 ,an in/rum5t us$ = det]m9+ ! angle ( ! flight pa?4 ,,incid5ce4 ,see ,,angle ,,( ,,incid5ce4 ,,incid5ce1 ,,negative4 ,! angle =m$ ) ! air /ream :5 front edge ( ! lift+ surface dips bel[ ! app>5t flight pa?4 ,,inh]5t ,,/ability4 ,/ability due to "s fix$ arrangem5t ( ! ma9 or auxili>y surfaces4 ,a ma*9e t requires me*anism or mov+ p>ts = its /ability is automatically b n inh]5tly /able4 ,,int]f]5ce4 ,! cr[d+ ( ! air/ream 9 ! gap ( a biplane or triplane causes ! surfaces to ,int]f]e1 & results 9 a loss ( lift4 ,j ,,joy ,,/ick4 ,see ,,control ,,/ick4 ,,jamb de ,,=ce 7,fr47 ,brac+ /rut4 ,,jante 7,fr47 ,rim ( :eel4 ,k ,,kite ,,balloon4 ,see ,,balloon4 ,,kilomet]4 ,fr5* metric unit ( di/ance4 ,"o kilomet] equals ,o4#fba /atute mile or ,o4#ecif nautical mile4 ,,kilogram4 ,metric unit ( weight4 ,"o kilogram equals #b4bje ,avoir4 p\nds4 ,,knock\t ,,hub4 ,an a]oplane *assis :eel hub provid$ ) removable bronze bu%+s4 ,,keel ,,plane ,,area499 ,! total effective side area ( an a]oplane :i* t5ds to prev5t skidd+ or side slipp+4 ,l ,,lat]al ,,/ability4 ,/ability ab\t ! =e & aft axis4 ,l',,avion 7,fr47 ,a]oplane4 ,,lam9at$4 ,built up 9 a s]ies ( lay]s4 ,,leeway499 ,! angul> deviation f a giv5 c\rse due to cross curr5ts ( w9d4 ,,lead+ ,,edge4 ,see ,,ent]+ ,,edge4 ,,lift4 ,! v]tical compon5t ( ! =ces produc$ on an a](oil by an air curr5t4 ,,lift ,,coeffici5t4 ,! lift p] unit ( area at a unit velocity 7,ky74 ,! ,am]ican lift coeffici5t is ! lift 9 p\nds p] squ>e foot at "o mile p] h\r4 ,,lift ,,capacity4 ,see ,,capacity4 ,,live ,,load4 ,! live load g5]ally includes ! pass5g]s1 pilot1 fuel1 oil1 in/rum5ts1 & portable baggage1 al?\gh 9 "s cases ! in/rum5ts are includ$ 9 ! dead load4 ,! live load is ! diff]5ce betwe5 ! total lift & ! dead load4 ,,load+ 7,,unit74 ,! unit load+ is ! load c>ri$ p] squ>e foot ( w+ surface1 or is equal to ! total weight divid$ by ! area4 ,,long]ons4 ,! pr9cipal =e & aft /ructural memb]s ( ! fuselage4 ,,longitud9als4 ,see ,,long]ons4 ,,longitud9al ,,/ability4 ,/ability 9 a =e & aft direction ab\t ! ,y axis4 ,m ,,mass4 ,! quantity ( matt]4 ,is equal to ! weight 9 p\nds divid$ by ! gravitation1 or g5]ally to ! weight divid$ by #cb4af4 ,,m&r9 de ,,bois 7,fr47 ,wood sp>4 ,,m>\flage 7,fr47 ,/rut tap+ ) fabric b&s4 ,,man*e ,a ,,balai 7,fr47 ,control /ick4 ,,manette 7,fr47 ,?rottle4 ,,m>1 ,,montant 7,fr47 ,int]plane /ruts4 ,,metac5t]499 ,! po9t ( int]section ( a /raight v]tical l9e pass+ ?r\gh ! c5t] ( gravity ( ! displac$ fluid or gas1 & ! l9e t =m]ly 0 a v]tical ?r\gh ! c5t] ( gravity be=e ! body 0 tipp$ f its position ( equilibrium4 ,!re is a diff]5t metac5t] = ea* position ( a float+ body4 ,,monoplane4 7,fr4 ,monoplan47 ,a type ( a]oplane ) a s+le w+ surface4 ,,monocoque ,,body 7,fr47 ,a body built up 9 tubul> =m out ( ?ree-ply wood1 ?us virtually =m+ a s+le piece body4 ,,monoplace 7,fr47 ,s+le seat]4 ,,monos\pape 7,fr47 ,s+le valve ,gnome motor4 ,,montgolfi] 7,fr47 ,hot air balloon4 ,,multiplane4 ,an a]oplane hav+ ! ma9 lift+ surface divid$ into a numb] ( p>ts4 ,n ,,nacelle4 ,! body or fuselage ( an a]oplane or dirigible4 ,x g5]ally signifies a dirigible body4 ,! %ort fuselage ( a pu%] type is (t5 call$ ! nacelle4 ,,natural ,,/ability4 ,see ,,inh]5t ,,/ability4 ,,negative ,,ail]ons4 ,ail]ons mak+ a negative angle ) ! w9d :5 9 normal flight4 ,! negative incid5ce ( ! ail]ons is decreas$ on ! l[ side & increas$ on ! high side s t ! high side is pu%$ d[n4 ,?is decreases ! drag on ! l[]1 inn] w+ 9 mak+ a turn1 & !re=e does n t5d to /all ! ma*9e4 ,,n]vures 7,fr47 ,w+ ribs4 ,,normal ,,plane4 ,a flat plane plac$ ) its surface at "r angles to ! air /ream4 ,,normal ,,pressure4 ,! pressure at "r angles to ! surface ( a plane4 ,,non-,,lift+ ,,tail4 ,a /abiliz+ surface arrang$ s t x c>ries no load 9 normal flight4 ,,nos+4 ,! memb] us$ = ! ent]+ edge ( ! w+4 ,,nose4 ,! front end ( ! a]oplane4 ,,nut4 7,fr4 ,ecru47 ,o ,,obliteur ,,r+s 7,fr47 ,! special pi/on r+s us$ on ! ,gnome motor4 ,,or?opt]4 ,any type ( w+ flapp+ ma*9e4 ,,orni?opt]4 ,a w+ flapp+ ma*9e t imitates bird flight4 ,,or?ogonal ,,biplane4 ,a biplane ) ! upp] & l[] lead+ edges 9 l9e4 ,,osmosis4 ,! transf] ( hydrog5 or o!r gas ?r\gh a balloon envelope by a molecul> process4 ,?is mu/ n be confus$ ) leakage due to holes4 ,,outrigg]4 ,see ,boom4 ,o4,w4,l4 ,,type4 ,a type ( ma*9e adapt$ = use ov] ,wat] & ,l&4 ,p ,,pancake4 ,a /raight v]tical drop due to /all+4 ,,pa? ,,( ,,flight4 ,! pa? ( ! c5t] ( gravity ( an aircraft 9 ref]5ce to ! air4 ,,palonni] 7,fr47 ,foot b> or lev]4 ,,panels4 ,! w+ sections includ$ betwe5 adjac5t /ruts4 ,,pat91 ,,pat9nage 7,fr47 ,skids4 ,,p>asol ,,type4 ,a monoplane 9 :i* ! w+ is locat$ above ! body4 ,,p5gu94 ,a tra9+ ma*9e :i* _c leave ! gr\nd4 ,,p]sonnel4 ,pilot & pass5g]s4 ,,petrol4 ,an ,engli% t]m = gasol9e4 ,,phillip',s ,,entry4 ,see ,,dipp+ ,,front ,,edge4 ,,pilot4 ,! op]ator ( aircraft4 ,,pilot ,,balloons4 ,small balloons s5t up to det]m9e ! direction ( ! w9d4 ,,pit*4 ,! =w>d di/ance travel$ ?r\gh by "o revolution ( ! propell]4 ,,pit*+4 ,a =e & aft oscillation1 fir/ head+ up & !n div+4 ,,pisci=m4 ,fi% =m4 ,,pique1 ,,vol 7,fr47 ,dive4 ,,plafond 7,fr47 ,ceil+ or maximum altitude obta9able4 ,,plan ,,c5tral 7,fr47 ,c5t] panel4 ,,plan*] 7,fr47 ,floor+4 ,,plan ,,fixe de ,,queue 7,fr47 ,/abiliz] surface4 ,,plan de ,,d]ive 7,fr47 ,/abiliz+ f94 ,,pitot ,,tube4 ,an in/rum5t = measur+ ! velocity ( an air curr5t4 ,,pontoon4 ,seaplane floats4 ,,poignee 7,fr47 ,h&le4 ,,pompe 7,fr47 ,pump4 ,,pompe ,a ,,pression 7,fr47 ,pressure pump4 ,,p\lie 7,fr47 ,pulley4 ,,propell]4 7,fr4 ,helice47 ,a device us$ 9 conv]t+ ! en]gy ( a motor into ! en]gy requir$ = ! propulsion ( an aircraft4 ,x consi/s ( two or m rotat+ blades :i* are incl9$ 9 reg>d to ! relative w9d1 & h5ce !y act z rot>y a]oplanes 9 creat+ a tractive =ce4 ,,propell] ,,rotation4 ,! direction ( rotation is det]m9$ :5 /&+ 9 ! slip /ream4 ,,pneu 7,fr47 ,pneumatic tire4 ,,pt]ygoid ,,aspect4 ,a w+ fly+ ) ! long edge to ! w9d is said to be 9 ,pt]ygoid ,aspect4 ,,pu%] ,,type4 ,an a]oplane ) ! propell] 9 ! re> ( ! w+s4 ,,pylon4 ,a m>k+ po/ on an a]oplane c\rse4 ,p ,,race ,,( ,a ,,propell]4 ,! air /ream ?r[n by ! propell]4 ,,radial ,,motor4 ,a motor ) ! cyl9d]s arrang$ 9 radial l9es ar\nd ! crankcase4 ,,rak$ ,,tips4 ,! tips are arrang$ at an angle ) ! w+ s t ! span ( ! trail+ edge is great] ?an t ( ! lead+ edge4 ,,rayons 7,fr47 ,spokes4 ,,reflex ,,curve4 ,an a](oil 9 :i* ! trail+ edge is giv5 an upw>d turn4 ,,rem\s 7,fr47 ,a d[nw>d curr5t ( air4 ,,res]voir 7,fr47 ,tank4 ,,res]voir ,,s\s ,,pression 7,fr47 ,pressure tank4 ,,resultant4 ,! total =ce result+ f ! application ( a numb] ( =ces4 ,,retreat4 ,back swept w+s ) ! tips to ! re> ( ! w+ c5t]4 ,,ribs4 ,! fabric =m+ memb] ( ! w+ /ructure4 ,,rudd]1 ,,v]tical4 ,a control surface us$ = /e]+ 9 a horizontal plane4 ,,roll4 ,oscillation ab\t ! =e & aft axis4 ,s ,,screw4 7,fr4 ,helice47 ,see ,,propell]4 ,,seaplane499 ,an a]oplane equipp$ ) floats or pontoons = l&+ on wat]4 ,,sc\t ,,type4 ,see ,,*as]4 ,,s]vice ,,tank4 ,! fuel tank fe$+ directly into ! c>buretors4 ,,set ,,back ,,w+s4 ,a type ( w+ 9 :i* ! lead+ edge is incl9$ backw>d z 9 ! ,mann biplane4 ,! trail+ edge is /raight4 ,,%ock ,,absorb]s4 ,an ela/ic device on ! *assis or l&+ ge> t absorbs vibration by all[+ a limit$ axle movem5t4 ,,side ,,slip499 ,slid+ d[n sideways1 & t[>d ! c5t] ( a turn4 ,?is is due to an excessive angle ( bank4 ,,siege 7,fr47 ,seat4 ,,similitude1 ,,laws ,,(4 ,! drag or resi/ance ( a small a]odynamic body does n increase 9 direct proportion ) ! area & spe$4 ,! laws gov]n+ ! relation betwe5 a model & a full size ma*9e are kn[n z ! laws ( ,similitude4 ,,skids499 7,fr4 ,pat91 ,patt9age47 ,long wood or metal runn]s atta*$ to ! *assis to prev5t ! nos+ ov] ( a ma*9e :5 l&+1 or to prev5t x f dropp+ into holes or dit*es on r\gh gr\nd4 ,x also acts :5 ! :eels collapse4 ,,skid ,,curta9s4 ,v]tical side curta9s or surfaces provid$ to r$uce ! skidd+ action on turns or to prev5t side slip4 ,,skidd+499 ,slid+ sideways away f ! c5t] ( ! turn4 ,x is due to insuffici5t bank+ on a turn4 ,,sk9 ,,friction4 ,! resi/ance caus$ by ! friction ( ! air along a surface4 ,,slip499 ,appli$ to propell] action1 ! slip is ! diff]5ce betwe5 ! actual advance ( an aircraft & ! !oretical advance calculat$ f ! product ( ! mean pit* & ! revolutions p] m9ute4 ,:5 ! propell] is held /ation>y1 ! slip is said to be #ajj p]c5t4 ,,slip ,,/ream4 ,! w9d /ream ?r[n by a propell]4 ,,so>+ ,,flight499 ,! su/5tation ( a w+ surface due to w9d curr5ts & )\t ! exp5diture ( o!r p[]4 ,so>+ flight is p]=m$ by gulls1 buzz>ds & vultures1 b no practical ma*9e has yet be5 built t w fly cont9u\sly )\t ! aid ( p[]4 ,,span4 7,fr4 ,env]gure47 ,! l5g? or longe/ dim5sion ( a w+1 g5]ally tak5 at "r angles to ! w9d /ream4 ,,sp>4 7,fr4 ,bras ,d',aile47 ,! ma9 w+ beams t transmit ! lift to ! body4 ,,spokes4 7,fr4 ,rayon47 ,,spread499 ,see ,,span4 ,,/ability499 ,! prop]ty ( an aircraft t causes x to return to a condition ( equilibrium aft] meet+ ) a di/urbance 9 flight4 ,,/agg]499 ,! advance ( ! lead+ edge ( ! upp] w+ ov] t ( ! l[] w+4 ,,/abiliz]499 7,fr4 ,/abilisateur47 ,a horizontal tail surface 7fix$7 us$ = damp+ out oscillations & = promot+ longitud9al /ability4 ,,/all+499 ,! condition ( an a]oplane t has lo/ ! spe$ necess>y = /e]age way or control4 ,,/all+ ,,angle4 ,see ,,critical ,,angle4 ,,/e]+ ,,:eel4 7,fr4 ,volant47 ,,/atoscope499 ,an in/rum5t = detect+ a small rate ( asc5t or desc5t4 ,us$ pr9cipally ) balloons4 ,,/ay ,,wire4 7,fr4 ,t5deur47 ,a wire or cable us$ z a tie to hold memb]s toge!r1 or to give /iffness to a /ructure4 ,,/ep499 ,a break 9 ! =m ( a float or fly+ boat bottom4 ,,/reaml9e4 ,a =m ( body t sets up no turbul5ce or eddies 9 pass+ ?r\gh air or liquid4 ,,/rut499 7,fr4 ,m>1 ,montant47 ,a compression memb] us$ 9 sep>at+ ! upp] & l[] w+s ( a biplane1 or ! long]ons ( ! fuselage4 ,,sweep ,,back4 ,see ,,retreat4 ,t ,,ta*omet]4 7,fr4 ,compte ,t\rs47 ,an in/rum5t = directly indicat+ ! revolutions p] m9ute4 ,,tail499 7,fr4 ,queue47 ,! re> "p ( an aircraft to :i* usually are atta*$ ! rudd]1 /abiliz]1 & elevator4 ,,tail ,,skid4 7,fr4 ,bequille47 ,a flexibly atta*$ rod :i* holds ! tail surfaces (f ! gr\nd1 & breaks ! l&+ %ocks on ! tail /ructure4 ,,tail ,,boom4 ,see ,,boom4 ,,tail ,,dive4 ,a v dang]\s backw>d dive4 ,,tail ,,sp94 ,a condition 9 :i* ! tail revolves ab\t a v]tical l9e pass+ ?r\gh ! c5t] ( gravity4 ,,t&em ,,planes4 ,a =m ( a]oplane 9 :i* ! w+s are plac$ "o aft] ano!r4 ,,taube4 ,an old type ( ,g]man or ,au/rian a]oplane ) back swept w+ tips4 ,,taxi4 ,to run along ! gr\nd4 ,,?imble4 7,fr4 ,cosse47 ,an oval groov$ metal fitt+ us$ = ! protection ( a cable loop at ! po9t ( atta*m5t4 ,,?ree-,,ply4 7,fr4 ,contreplaque47 ,a wood %eet compos$ ( ?ree lay]s ( wood glu$ toge!r1 ! l9e ( gra9 cross+ at ea* jo9t4 ,,?ru/4 ,! propulsive =ce ex]t$ by a propell]4 ,,?ru/ ,,d$uction499 ,! r$uction ( ?ru/ due to a r$uction ( pressure "u ! /]n ( ! aircraft4 ,,tirant 7,fr47 ,brac+ tubes4 ,,torque4 ,! turn+ =ce or mom5t ex]t$ by ! motor4 ,,toile 7,fr47 ,l954 ,,torque ,,w>p4 ,! am\nt ( w>p1 or p]man5t set 9 ! ail]ons necess>y to ov]come ! torque or twi/+ effect ( ! motor4 ,9 "s ma*9es ! torque is ov]come by *ang+ ! angle ( incid5ce at ! w+ tips4 ,,tractor ,,biplane4 ,a type ( a]oplane 9 :i* ! propell] is plac$ 9 front ( ! w+s s t x pulls ! ma*9e along4 ,,trail+ ,,edge4 ,! edge ( a w+ at :i* ! air /ream leaves ! surface4 ,,tra9 ,d',,att]rissage 7,fr47 ,l&+ ge>4 ,,transfil 7,fr47 ,cord w9d+ on ! /ruts4 ,,triplane4 7,fr4 ,triplan47 ,an a]oplane ) ?ree sup]pos$ w+s4 ,,turbul5ce4 ,! eddies or discont9uity caus$ by a body or surface pass+ ?r\gh ! air4 ,u ,,useful ,,weight4 ,! diff]5ce betwe5 ! total lift & ! dead load4 ,?is comprises ! pilot & pass5g]1 ! weight ( ! fuel1 baggage & in/rum5ts4 ,,unit ,,load+4 ,! weight p] squ>e foot ( ma9 w+ surface4 ,v ,,vol ,,plane 7,fr47 ,see ,,glide4 ,,vol ,,pique 7,fr47 ,see ,,dive4 ,,volant 7,fr47 ,/e]+ :eel4 ,,v]nis 7,fr47 ,v>ni%4 ,,vril 7,fr47 ,sp9n+ nose dive4 ,,volets de ,,pr(ondeur 7,fr47 ,elevator flaps4 ,w ,,w>p ,,control499 ,lat]al control obta9$ by twi/+ ! w+ tips4 ,,wa%\t4 ,decreas$ camb] or incid5ce t[>d ! w+ tips4 ,,wea!r-,,cock ,,/ability4 ,/ability 9 ! l9e ( travel1 or ) ! relative w9d1 s t ! ma*9e always t5ds to head into ! w9d4 ,,:ale ,,type4 ,a spe$ type biplane 9 :i* ! body entirely fills ! gap betwe5 ! upp] & l[] w+s4 ,,:irl+ ,,table4 ,a te/+ device 9 :i* a model w+ or body is plac$ at ! end ( a revolv+ arm4 ,,w+s499 7,fr4 ,aile47 ,! ma9 support+ surfaces ( an a]oplane4 ,,work+ ,,face4 ,! face ( a propell] blade ly+ next to ! slip /ream4 ,,wake ,,ga9499 ,due to sk9 friction & eddies1 a mov+ aircraft drags a c]ta9 am\nt ( ! surr\nd+ air ) x4 ,?is r$uces ! effective resi/ance ( ! hull & increases ! effective pit* ( a pu%] propell] s9ce ! latt] acts on a =w>d mov+ mass ( air4 ,?is is ,wake ga94 ,illu/ration3 ,laun*+ ) ,catapult f ,deck ( ,battle%ip