,a]oplanes by ,j4 ,s4 ,z]be ,scann$ by ,*>les ,kell] ) ,omni,page ,pr(essional ,,ocr s(tw>e ,,a]oplanes ,?is "w is n int5d$ to set =? ! exploits ( aviators nor to give a hi/ory ( ! ,art4 ,x is a book ( in/ructions int5d$ to po9t out ! !ories ( fly+1 z giv5 by ! pione]s1 ! practical application ( p[] to ! v>i\s fly+ /ructures2 h[ !y are built1 ! diff]5t me?ods ( controll+ !m2 ! advantages & disadvantages ( ! types n[ 9 use2 & sugge/ions z to ! directions 9 :i* improvem5ts are requir$4 ,x di/9ctly po9ts out :]e9 me*anical flight diff]s f bird flight1 & :at are ! relations ( %ape1 =m1 size & weight4 ,x treats ( kites1 glid]s & model a]oplanes1 & has an ,int]e/+ *apt] on ! a]oplane & its uses ,9 ! great w>4 ,all ! illu/rations h be5 specially prep>$ = ! "w4 ,e ,boy's ,me*anical ,libr>y ,,a]oplanes ,,by ,j4 ,s4 ,,z]be1 ,m4 ,e4 ,au?or ( ,automobiles--,motors ,,copyright1 #aiae1 ,,by ,,cupples ,,leon ,,company ,,ny ,,cont5ts ,,introductory ,,*apt] ,i4 ,,!ories ,,& ,,facts ,,ab\t ,,fly+ ,! ,sci5ce ( ,aviation4 ,ma*9e ,types4 ,%ape or ,=m n ,ess5tial4 ,a ,/one z a ,fly+ ,ma*9e4 ,p[] ! ,great ,elem5t4 ,gravity z ,p[]4 ,mass & ,elem5t 9 ,fly+4 ,mom5tum a ,factor4 ,resi/ance4 ,h[ ,resi/ance ,affects ,%ape4 ,mass & ,resi/ance4 ,! ,e>ly ,t5d5cy to ,elim9ate ,mom5tum4 ,light ,ma*9es ,un/able4 ,! ,application ( ,p[]4 ,! ,support+ ,surfaces4 ,area n ! ,ess5tial ,?+4 ,! ,law ( ,gravity4 ,gravity4 ,inde/ructibility ( ,gravitation4 ,di/ance ,r$uces ,gravitational ,pull4 ,h[ ,motion ,antagonizes ,gravity4 ,a ,tang5t4 ,tang5tial ,motion ,repres5ts ,c5trifugal ,pull4 ,equaliz+ ! ,two ,motions4 ,lift & ,drift4 ,normal ,pressure4 ,head ,resi/ance4 ,measur+ ,lift & ,drift4 ,pressure at ,diff]5t ,angles4 ,diff]5ce ,betwe5 ,lift & ,drift 9 ,motion4 ,tables ( ,lift & ,drift4 ,:y ,tables ( ,lift & ,drift are ,wrong4 ,langley's ,law4 ,mov+ ,planes vs4 ,w9ds4 ,mom5tum n ,consid]$4 ,! ,flight ( ,birds4 ,! ,d[nw>d ,beat4 ,! ,concav$ ,w+4 ,fea!r ,/ructure ,consid]$4 ,webb$ ,w+s4 ,! ,angle ( ,movem5t4 ,an ,initial ,movem5t or ,impulse ,necess>y4 ,a ,w$g+ ,motion4 ,no ,my/]y 9 ! ,wave ,motion4 ,h[ ,birds ,poise ) ,flapp+ ,w+s4 ,n>r[- w+$ ,birds4 ,initial ,movem5t ( ,so>+ ,birds4 ,so>+ ,birds ,move ,swiftly4 ,muscul> ,en]gy ,ex]t$ by ,so>+ ,birds4 ,w+s n ,motionless4 ,,*apt] ,,ii4 ,,pr9ciples ,,( ,,a]oplane ,,flight ,spe$ z "o ( ! ,elem5ts4 ,%ape & ,spe$4 ,:at ,squ>e ( ! ,spe$ ,means4 ,action ( a ,skipp]4 ,angle ( ,incid5ce4 ,spe$ & ,surface4 ,control ( ! ,direction ( ,flight4 ,v]tical ,planes4 ,,*apt] ,,iii4 ,,! ,,=m ,,or ,,%ape ,,( ,,fly+ ,,ma*9es ,! ,!ory ( ,copy+ ,nature4 ,hulls ( ,vessels4 ,man ,does n ,copy ,nature4 ,pr9ciples ,ess5tial1 n ,=ms4 ,nature n ! ,guide z to ,=ms4 ,! ,propell] ,type4 ,:y ,specially-design$ ,=ms ,improve ,natural ,/ructures4 ,me*anism ,devoid ( ,intellig5ce4 ,a ,ma*9e ,mu/ ,h a ,sub/itute = ,intellig5ce4 ,/udy ( ,bird ,flight ,useless4 ,%ape ( ,support+ ,surface4 ,! ,tr\ble ,aris+ ,f ,out/ret*$ ,w+s4 ,d5sity ( ! ,atmosph]e4 ,ela/icity ( ! ,air4 ,air ,holes4 ,responsibility = ,accid5ts4 ,! ,turn+ ,movem5t4 ,c5trifugal ,action3 ,! ,w>p+ ,planes4 ,,*apt] ,,iv4 ,,=e ,,& ,,aft ,,control ,! ,bird ,type ( ,=e & ,aft ,control4 ,angle & ,direction ( ,flight4 ,:y ,%\ld ! ,angle ( ! ,body ,*ange4 ,*ang+ ,angle ( ,body n ,safe4 ,a ,non-*ang+ ,body4 ,desc5d+ ,positions by ,p[] ,control4 ,cutt+ (f ! ,p[]4 ,! ,/>t+ ,movem5t4 ,! ,sugge/$ ,type4 ,! ,l[ ,c5t] ( ,gravity4 ,=e & ,aft ,oscillations4 ,application ( ! ,new ,pr9ciple4 ,l[ ,weight n ,necess>y ) ,syn*ron\sly- mov+ w+s4 ,,*apteb ,v4 ,,diff]5t ,,ma*9e ,,types ,,& ,,_! ,,*>act]i/ics ,! ,helicopt]4 ,a]oplanes4 ,! ,monoplane4 ,its ,advantages4 ,its ,disadvantages4 ,! ,bi-plane4 ,/ability 9 ,bi-planes4 ,! ,or?opt]4 ,nature's ,type n ,uni=m4 ,!ories ,ab\t ,flight ( ,birds4 ,in/9ct4 ,! ,mode ( ,motion4 ,! ,w+ ,/ructure4 ,! ,w+ ,movem5t4 ,! ,helicopt] ,motion4 ,,*apt] ,,vi4 ,,! ,,lift+ ,,surfaces ,,( ,,a]oplanes ,relative ,spe$ & ,angle4 ,n>r[ ,planes ,mo/ ,effective4 ,/ream ,l9es ,along a ,plane4 ,! ,c5t] ( ,pressure4 ,air ,l9es on ! ,upp] ,side ( a ,plane4 ,r>efi$ ,area4 ,r>efaction ,produc$ by ,motion4 ,! ,concav$ ,plane4 ,! ,c5t] ( ,pressure4 ,utiliz+ ! ,r>efi$ ,area4 ,*ang+ ,c5t] ( ,pressure4 ,plane ,mon/rosities4 ,! ,bird ,w+ ,/ructure4 ,torsion4 ,! ,bat's ,w+4 ,an ,abnormal ,%ape4 ,! ,tail z a ,monitor4 ,,*apt] ,,vii4 ,,abnormal ,,fly+ ,,/unts ,,& ,,spe$s ,lack ( ,improvem5ts 9 ,ma*9es4 ,m5 ,exploit$ & n ,ma*9es4 ,abnormal ,fly+ ( no ,value4 ,! ,art ( ,juggl+4 ,practical ,uses ! ,be/ ,te/4 ,concav$ & ,convex ,planes4 ,h[ ,mom5tum is a ,factor 9 ,inv]t$ ,fly+4 ,! ,turn+ ,movem5t4 ,:5 ,concav$ ,planes are ,desirable4 ,! ,spe$ ,mania4 ,uses ( ,fly+ ,ma*9es4 ,p]fection 9 ,ma*9es ,mu/ ,come ,be=e ,spe$4 ,! ,range ( its ,uses4 ,comm]cial ,utility4 ,,*apt] ,,viii4 ,,kites ,,& ,,glid]s ,! ,dragon ,kite4 ,its ,con/ruction4 ,! ,malay ,kite4 ,dih$ral ,angle4 ,! ,common ,kite4 ,! ,b[ ,kite4 ,! ,box ,kite4 ,! ,voison ,bi-plane4 ,lat]al ,/ability 9 ,kites1 n ,conclusive z to ,planes4 ,! ,spe> ,kite4 ,! ,cellul> ,kite4 ,tetrah$ral ,kite4 ,! ,deltoid4 ,! ,dunne ,fly+ ,ma*9e4 ,rotat+ ,kite4 ,kite ,pr9ciples4 ,lat]al ,/ability 9 ,kites4 ,simil>ity ( ,=e & ,aft ,control4 ,glid+ ,flight ,"o ( ! ,uses ( ,glid] ,exp]im5ts4 ,h9ts 9 ,glid+4 ,,*apt] ,,ix4 ,,a]oplane ,,con/ruction ,lat]al & ,=e & ,aft4 ,transv]se4 ,/ability & ,/abilization4 ,! ,wright ,sy/em4 ,controll+ ! ,w>p+ ,ends4 ,! ,curtiss ,w+s4 ,! ,f>man ,ail]ons4 ,features ,well ,develop$4 ,depress+ ! ,re> ,end4 ,det]m9+ ! ,size4 ,rule = ,plac+ ! ,planes4 ,elevat+ ,plane4 ,action 9 ,alight+4 ,! ,monoplane4 ,! ,common ,fly4 ,/ream ,l9es4 ,! ,monoplane ,=m4 ,,*apt] ,x4 ,,p[] ,,& ,,its ,,application ,features 9 ,p[] ,application4 ,am\nt ( ,p[] ,necess>y4 ,! ,pull ( ! ,propell]4 ,foot ,p\nds ,small ,am\nt ( ,p[] ,available4 ,high ,propell] ,spe$ ,important4 ,wid? & ,pit* ( ,blades4 ,effect ( ,increas+ ,propell] ,pull4 ,disposition ( ! ,planes4 ,diff]5t ,spe$s ) ,same ,p[]4 ,increase ( ,spe$ ,adds to ,resi/ance4 ,h[ ,p[] ,decreases ) ,spe$4 ,h[ to ,calculate ! ,p[] ,appli$4 ,pull+ ,aga9/ an ,angle4 ,! ,horizontal & ! ,v]tical ,pull4 ,! ,p[] ,m\nt+4 ,secur+ ! ,propell] to ! ,%aft4 ,vibrations4 ,weaknesses 9 ,m\nt+4 ,! ,gasol9e ,tank4 ,:]e to ,locate ! ,tank4 ,! ,dang] to ! ,pilot4 ,! ,clos$-9 ,body4 ,/>t+ ! ,ma*9e4 ,propell]s ) ,v>y+ ,pit*4 ,,*apt] ,,xi4 ,,fly+ ,,ma*9e ,,accessories ,! ,anemomet]4 ,! ,anemograph4 ,! ,anemometrograph4 ,! ,spe$ ,indicator4 ,air ,pressure ,indicator4 ,det]m9+ ! ,pressure ,f ! ,spe$4 ,calculat+ ,pressure ,f ,spe$4 ,h[ ! ,figures are ,det]m9$4 ,conv]t+ ,h\rs ,into ,m9utes4 ,*ang+ ,spe$ ,h\rs to ,seconds4 ,pressure z ! ,squ>e ( ! ,spe$4 ,gyroscopic3,balance4 ,! ,pr9ciples ,involv$4 ,! ,application ( ! ,gyroscope4 ,=e & ,aft ,gyroscopic ,control4 ,angle ,indicator4 ,p5dulum ,/abiliz]4 ,/e]+ & ,controll+ ,:eel4 ,automatic ,/abiliz+ ,w+s4 ,b>omet]s4 ,an]oid ,b>omet]4 ,hydroplanes4 ,su/a9+ ,weight ( ,pontoons4 ,%ape ( ! ,pontoon4 ,,*apt] ,,xii4 ,,exp]im5tal ,,"w ,,9 ,,fly+ ,c]ta9 ,conditions 9 ,fly+4 ,heat 9 ,air4 ,motion ,:5 9 ,flight4 ,*ang+ ,atmosph]e4 ,asc5d+ ,curr5ts4 ,aspirate ,curr5ts4 ,out/ret*$ ,w+s4 ,! ,/>t+ ,po9t4 ,! ,vital ,"p ( ! ,ma*9e4 ,/udy+ ! ,action ( ! ,ma*9e4 ,elevat+ ! ,ma*9e4 ,h[ to ,practice4 ,! ,fir/ ,/age4 ,pati5ce ! ,mo/ ,difficult ,?+4 ,! ,second ,/age4 ,! ,?ird ,/age4 ,obs]vations ,:ile 9 ,flight4 ,fly+ 9 a ,w9d4 ,fir/ ,trials 9 a ,quiet ,atmosph]e4 ,mak+ ,turns4 ,! ,f\r? ,/age4 ,! ,figure #h4 ,! ,vol ,plane4 ,! ,l&+4 ,fly+ ,altitudes4 ,,*apt] ,,xiii4 ,,! ,,propell] ,propell] ,*anges4 ,propell] ,%ape4 ,! ,diamet]4 ,pit*4 ,lay+ ,out ! ,pit*4 ,pit* ,rule4 ,lam9at$ ,con/ruction4 ,lay+ up a ,propell] ,=m4 ,mak+ ,wide ,blades4 ,propell] ,outl9e4 ,= ,high ,spe$s4 ,increas+ ,propell] ,effici5cy4 ,,*apt] ,,xiv4 ,,exp]im5tal ,,glid]s ,,& ,,model ,,a]oplanes ,! ,relation ( ,models to ,fly+ ,ma*9es4 ,lessons ,f ,models4 ,fly+ ,model ,a]oplanes4 ,an ,effici5t ,glid]4 ,! ,deltoid ,=mation4 ,rac+ ,models4 ,! ,p[] = ,model ,a]oplanes4 ,mak+ ! ,propell]4 ,mat]ial = ! ,propell]4 ,rubb]4 ,propell] ,%ape & ,size4 ,support+ ,surfaces4 ,,*apt] ,,xv4 ,,! ,,a]oplane ,,9 ,,! ,,great ,,w> ,balloon ,obs]vations4 ,*ang$ ,conditions 9 ,w>f>e4 ,! ,ef=t to ,conceal ,combatants4 ,smokeless ,p[d]4 ,inv5tions to ,attack ,a]ial ,craft4 ,functions ( ! ,a]oplane 9 ,w>4 ,bomb-?r[+ ,te/s4 ,me?od = ,det]m9+ ! ,movem5t ( a ,bomb4 ,! ,great ,ext5t ( ,mod]n ,battle ,l9es4 ,! ,a]oplane ,detect+ ! ,movem5ts ( ,armies4 ,! ,effective ,height = ,sc\t+4 ,sizes ( ,objects at ,great ,di/ances4 ,"s ,d>+ ,feats 9 ,w>4 ,! ,g]man ,taube4 ,h[ ,a]oplanes ,report ,obs]vations4 ,signal ,flags4 ,h[ ,us$4 ,casualties ,due to ,bombs ,f ,a]oplanes4 ,,gloss>y ,,introductory ,9 prep>+ ?is volume on ,fly+ ,ma*9es ! aim has be5 to pres5t ! subject 9 su* a mann] z w appeal to boys1 or beg9n]s1 9 ?is field ( human activity4 ,! art ( aviation is 9 a mo/ primitive /ate4 ,s _m curi\s !ories h be5 br\ght out t1 :ile !y furni% food = ?\ght1 d n1 9 any way1 advance or improve ! /ructure ( ! ma*9e itself1 nor are !y ( any s]vice 9 tea*+ ! novice h[ to fly4 ,! au?or consid]s x ( f> m importance to tea* "r pr9ciples1 & correct reason+ ?an to furni% complete diagrams ( ! details ( a ma*9e4 ,! =m] tea* ! art1 :]eas ! latt] m]ely po9t out ! me*anical arrangem5ts1 indep5d5tly ( ! reasons = mak+ ! /ructures 9 t p>ticul> way4 ,relat+ ! hi/ory ( an art1 :ile x may be int]e/+ read+1 does n ev5 lay ! f\ndations ( a k ( ! subject1 h5ce t field has be5 left to o!rs4 ,! boy is naturally inquisitive1 & he is int]e/$ 9 kn[+ ,,:y c]ta9 ?+s are necess>y1 & ! reasons = mak+ /ructures 9 p>ticul> ways4 ,t is ! void into :i* ^! pages are plac$4 ,! au?or kn[s f practical exp]i5ce1 :ile exp]im5t+ ) & build+ a]oplanes1 h[ eag]ly e boy inquires into details4 ,!y want ! reasons = ?+s4 ,"o su* in/ance is relat$ to evid5ce ?is _s ( inquiry4 ,"s boys 7 discuss+ ! curv$ plane /ructure4 ,"o ( !m v5tur$ ! op9ion t birds' w+s 7 concav$ on ! l[] side4 ,b1 retort$ ano!r1 :y are birds' w+s holl[$8 ,?is 0 go+ back to fir/ pr9ciples at "o leap4 ,x 0 n satisfy+ en\gh to "k t man 0 copy+ nature4 ,x 0 m important to "k :y nature orig9at$ t type ( =mation1 because1 x is obvi\s1 t if su* /ructures are univ]sal 9 ! k+dom ( fly+ creatures1 !re mu/ be "s und]ly+ pr9ciple :i* acc\nt$ = x4 ,x is n ! aim ( ! book to tea* ! art ( fly+1 b r to %[ h[ & :y ! pres5t ma*9es fly4 ,! mak+ & ! us+ are sep>ate & indep5d5t functions1 & ( ! two ! m important is ! k h[ to make a correct ma*9e4 ,hundr$s ( workm5 may contribute to ! build+ ( a locomotive1 b "o man1 n a build]1 kn[s bett] h[ to h&le x4 ,to manipulate a fly+ ma*9e is m difficult to navigate ?an su* a pond]\s ma*9e1 because x requires peculi> tal5ts1 & ! build+ is /ill m important & complicat$1 & requires ! ex]cise ( a k9d ( skill n necess>y 9 ! locomotive4 ,! art is /ill v "y2 s mu* is done :i* arises f speculation & !ories2 too mu* dep5d5ce is plac$ on ! aviator2 ! desire 9 ! pres5t condition ( ! art is to exploit ! man & n ! ma*9e2 d>e-devil exhibitions seem to be m important ?an p]fect+ ! me*anism2 & su* useless attempts z fly+ upside d[n1 loop+ ! loop1 & *>act]i/ic displays ( t k9d1 are ( no value to ! art4 ,,! ,,au?or4 ,,a]oplanes ,,*apt] ,i ,,!ories ,,& ,,facts ,,ab\t ,,fly+ ,,! ,,sci5ce ,,( ,,aviation4--,x may be d\bt$ :e!r !re is su* a ?+ z a sci5ce ( aviation4 ,s9ce ,langley1 on ,may #f1 #ahif1 flew a motor-propell$ t&em monoplane = a m9ute & an half1 )\t a pilot1 & ! ,wright ,bro!rs 9 #aijc succe$$ 9 fly+ a bi-plane ) a pilot abo>d1 ! univ]sal op9ion has be51 t fly+ ma*9es1 to be successful1 mu/ foll[ ! /ructural =m ( birds1 & t %ape has ev]y?+ to d ) fly+4 ,we may be able to le>n some?+ by c>efully exam9+ ! diff]5t views pres5t$ by ^? int]e/$ 9 ! art1 & !n see h[ !y con=m to ! facts z br\ght out by ! actual exp]im5ts4 ,,ma*9e ,,types4--,!re is really b "o type ( plane ma*9e4 ,:ile te*nically two =ms are kn[n1 namely1 ! monoplane & ! bi-plane1 !y are bo? dep5d5t on out/ret*$ w+s1 long] transv]sely ?an =e & aft1 s f> z ! support+ surfaces are conc]n$1 & ) ! ma9 weight high 9 ! /ructure1 ?us1 9 e p>ticul>1 con=m+ to ! =m po9t$ out by nature z ! app>5tly correct type ( a fly+ /ructure4 ,,%ape ,,or ,,=m ,,n ,,ess5tial4--,x may be /at$ ) p]fect confid5ce1 t %ape or =m has no?+ to d ) ! m]e act ( fly+4 ,x is simply a "q ( p[]4 ,?is is a broad ass]tion1 & its mean+ may be bett] und]/ood by exam9+ ! "q ( flight 9 a broad s5se4 ,a ,,/one ,,z ,a ,,fly+ ,,ma*9e4--,:5 a /one is propell$ ?r\gh space1 %ape is ( no importance4 ,if x has r\gh & jagg$ sides its spe$ or its di/ance may be limit$1 z comp>$ ) a p]fectly r\nd$ =m4 ,x may be made 9 su* a %ape z w (f] less resi/ance to ! air 9 flight1 b its actual propulsion ?r\gh space does n dep5d on h[ x is made1 b on ! p[] :i* propell$ x1 & su* a missile is a true heavi]-?an-air ma*9e4 ,a fly+ object ( ?is k9d may be s con/ruct$ t x w g a great] di/ance1 or require less p[]1 or ma9ta9 itself 9 space at less spe$2 b x is a fly+ ma*9e1 nev]!less1 9 ! s5se t x moves horizontally ?r\gh ! air4 ,,p[] ,,! ,,great ,,elem5t4--,n[1 let u exam9e ! "q ( ?is p[] :i* is able to set gravity at naught4 ,! quality call$ en]gy resides 9 mat]ial itself4 ,x is some?+ )9 matt]1 & does n come f )\t4 ,! p[] d]iv$ f ! explosion ( a *>ge ( p[d] comes f )9 ! sub/ance2 & s ) fall+ wat]1 or ! expansive =ce ( /eam4 ,,gravity ,,z ,,p[]4--,inde$1 ! v act ( ! ball gradually mov+ t[>d ! e>?1 by ! =ce ( gravity1 is an illu/ration ( a p[] )9 ! object itself4 ,long aft] ,galileo firmly e/abli%$ ! law ( fall+ bodies x began to dawn on sci5ti/s t weight is =ce4 ,aft] ,newton e/abli%$ ! law ( gravitation ! old idea1 t p[] 0 a prop]ty ( ea* body1 pass$ away4 ,9 its /ead we n[ h ! firmly e/abli%$ view1 t p[] is some?+ :i* mu/ h at lea/ two p>ts1 or consi/ 9 pairs1 or two elem5ts act+ toge!r4 ,?us1 a /one pois$ on a cliff1 :ile x ex]ts no p[] :i* c be utiliz$1 has1 nev]!less1 :at is call$ pot5tial en]gy4 ,:5 x is pu%$ f its lodg+ place k9etic en]gy is develop$4 ,9 bo? cases1 gravity1 act+ 9 conjunction ) ! mass ( ! /one1 produc$ p[]4 ,s 9 ! case ( gunp[d]4 ,x is ! unity ( two or m sub/ances1 t causes ! expansion call$ p[]4 ,! heat ( ! fuel conv]t+ wat] into /eam1 is ano!r illu/ration ( ! unity ( two or m elem5ts1 :i* are necess>y to produce en]gy4 ,,mass ,,an ,,elem5t ,,9 ,,fly+4--,! boy :o reads ?is w smile1 z he tells u t ! p[] :i* propell$ ! ball ?r\gh ! air came f ! ?r[] & n f ! ball itself4 ,let u exam9e ?is claim1 :i* came f a real boy1 & is ano!r illu/ration h[ acute 8 m9d is on subjects ( ?is "*4 ,we h two balls ! same diamet]1 "o ( iron weigh+ a half p\nd1 & ! o!r ( cotton weigh+ a half ounce4 ,! weight ( "o is1 !re=e1 sixte5 times great] ?an ! o!r4 ,suppose ^! two balls are ?r[n ) ! exp5diture ( ! same p[]4 ,:at w be ! result6 ,! iron ball w g mu* f>!r1 or1 if project$ aga9/ a wall w /rike a h>d] bl[ ?an ! cotton ball4 ,,mom5tum ,a ,,factor4--,ea* _h transf]r$ to x a motion4 ,! initial spe$ 0 ! same1 & ! p[] set up equal 9 ! two4 ,:y ?is diff]5ce1 ,! answ] is1 t x is 9 ! mat]ial itself4 ,x 0 ! mass or d5sity :i* acc\nt$ = ! diff]5ce4 ,x 0 mass multipli$ by spe$ :i* gave x ! p[]1 call$1 9 ?is case1 mom5tum4 ,! iron ball weigh+ eight ounces1 multipli$ by ! assum$ spe$ ( #ej feet p] second1 equals #djj units ( "w4 ,! cotton ball1 weigh+ #a_/b ounce1 ) ! same initial spe$1 repres5ts #be units ( "w4 ,! t]m unit ( "w means a measurem5t1 or a factor :i* may be us$ to measure =ce4 ,x w ?us be se5 t x 0 n ! ?r[] :i* gave ! p[]1 b ! article itself4 ,a fea!r ball ?r[n "u ! same conditions1 w\ld produce a half unit ( "w1 & ! iron ball1 !re=e1 produc$ #hjj times m en]gy4 ,,resi/ance4--,n[1 9 ! movem5t ( any body ?r\gh space1 x meets ) an enemy at e /ep1 & t is air resi/ance4 ,?is is mu* m effective aga9/ ! cotton ?an ! iron ball3 or1 x might be express$ 9 ano!r way3 ,! mom5tum1 or ! p[]1 resid+ 9 ! metal ball1 is s mu* great] ?an t )9 ! cotton ball t x travels f>!r1 or /rikes a m effective bl[ on impact ) ! wall4 ,,h[ ,,resi/ance ,,affects ,,! ,,%ape4--,x is because ( ?is c\nt]=ce1 resi/ance1 t %ape becomes important 9 a fly+ object4 ,! metal ball may be flatt5$ out into a ?9 disk1 & n[1 :5 ! same =ce is appli$1 to project x =w>dly1 x w g z mu* f>!r z ! diff]5ce 9 ! air impact aga9/ ! two =ms4 ,,mass ,,& ,,resi/ance4--,ow+ to ! fact t resi/ance acts ) su* a ret>d+ =ce on an object ( small mass1 & x is difficult to set up a rapid motion 9 an object ( great d5sity1 lightness 9 fly+ ma*9e /ructures has be5 consid]$1 9 ! pa/1 ! pr9cipal ?+ necess>y4 ,,! ,,e>ly ,,t5d5cy ,,to ,,elim9ate ,,mom5tum4-- ,build]s ( fly+ ma*9es1 = sev]al ye>s1 s\ght to elim9ate ! v ?+ :i* gives en]gy to a horizontally-movable body1 namely1 mom5tum4 ,in/ead ( mom5tum1 some?+ _h to be sub/itut$4 ,?is 0 f\nd 9 s arrang+ ! ma*9e t its weight1 or a portion ( x1 w\ld be su/a9$ 9 space by ! v elem5t :i* seeks to ret>d its flight1 namely1 ! atmosph]e4 ,if !re %\ld be no mat]ial sub/ance1 l air1 !n ! only way 9 :i* a heavi]-?an-air ma*9e c\ld ev] fly1 w\ld be by propell+ x ?r\gh space1 l ! ball 0 ?r[n1 or by "s sort ( impulse or reaction me*anism on ! air-%ip itself4 ,x c\ld get no support f ! atmosph]e4 ,,light ,,ma*9es ,,un/able4--,gradually ! "q ( weight is solv+ itself4 ,aviators are beg9n+ to realize t mom5tum is a wond]ful prop]ty1 & a mo/ important elem5t 9 fly+4 ,! safe/ ma*9es are ^? :i* h weight4 ,! light1 will[y ma*9es are subject to e caprice ( ! w9d4 ,!y are notori\sly un/able 9 flight1 & are dang]\s ev5 9 ! h&s ( exp]ts4 ,,! ,,application ,,( ,,p[]4--,! ?+ n[ to consid] is n =m1 or %ape1 or ! di/ribution ( ! support+ surfaces1 b ,,h[ to apply ! p[] s t x w rapidly transf] a ma*9e at re/ to "o 9 motion1 & !reby get ! prop] support on ! atmosph]e to hold x 9 flight4 ,,! ,,support+ ,,surfaces4--,?is br+s u to ! consid]ation ( "o ( ! fir/ great problems 9 fly+ ma*9es1 namely1 ! support+ surfaces1--n its =m1 %ape or arrangem5t1 7:i* w be tak5 up 9 _! prop] places71 b ! area1 ! dim5sions1 & ! angle necess>y = flight4 ,,area ,,n ,,! ,,ess5tial ,,?+4--,! hi/ory ( fly+ ma*9es1 %ort z x is1 furni%es _m examples ( "o /rik+ fact3 ,t area has b little to d ) su/a9+ an a]oplane :5 once 9 flight4 ,! fir/ ,wright fly] weigh$ #gda p\nds1 _h ab\t #djj squ>e feet ( plane surface1 & 0 ma9ta9$ 9 ! air ) a #ab horse p[] eng9e4 ,true1 t ma*9e 0 %ot into ! air by a catapult4 ,motion hav+ once be5 imp>t$ to x1 ! only ?+ necess>y = ! motor 0 to ma9ta9 ! spe$4 ,!re are _m in/ances to %[ t :5 once 9 flight1 "o horse p[] w su/a9 ov] #ajj p\nds1 & ea* squ>e foot ( support+ surface w ma9ta9 #ij p\nds 9 flight4 ,,! ,,law ,,( ,,gravity4--,z ! ef=t to fly may be consid]$ 9 ! light ( a /ruggle to avoid ! laws ( nature ) respect to matt]1 x may be well to consid] ?is great =ce z a fitt+ prelude to ! /udy ( our subject4 ,prop] und]/&+1 & use ( t]ms is v desirable1 s t we mu/ n confuse !m4 ,?us1 weight & mass are n ! same4 ,weight v>ies ) ! latitude1 & x is diff]5t at v>i\s altitudes2 b mass is always ! same4 ,if project$ ?r\gh space1 a c]ta9 mass w\ld move s z to produce mom5tum1 :i* w\ld be equal at all places on ! e>?'s surface1 or at any altitude4 ,gravity has be5 call$ weight1 & weight gravity4 ,! real diff]5ce is pla9 if gravity is consid]$ z ! attraction ( mass = mass4 ,gravity is g5]ally kn[n & consid]$ z a =ce :i* seeks to draw ?+s to ! e>?4 ,?is is too n>r[4 ,gravity acts 9 all directions4 ,two balls susp5d$ f /r+s & hung 9 close proximity to ea* o!r w mutually attract ea* o!r4 ,if "o has d\ble ! mass x w h twice ! attractive p[]4 ,if "o is d\bl$ & ! o!r tripl$1 ! attraction w\ld be increas$ six times4 ,b if ! di/ance %\ld be d\bl$ ! attraction w\ld be r$uc$ to "o-f\r?2 & if ! di/ance %\ld be tripl$ !n ! pull w\ld be only "o-n9?4 ,! =ego+ is ! sub/ance ( ! law1 namely1 t all bodies attract all o!r bodies ) a =ce directly 9 proportion to _! mass1 & inv]sely z ! squ>e ( _! di/ance f "o ano!r4 ,to expla9 ?is we cite ! foll[+ illu/ration3 ,two bodies1 ea* hav+ a mass ( #d p\nds1 & "o in* ap>t1 are attract$ t[>d ea* o!r1 s !y t\*4 ,if "o has twice ! mass ( ! o!r1 ! small] w draw ! l>g] only "o-qu>t] ( an in*1 & ! l>ge "o w draw ! o!r ?ree-qu>t]s ( an in*1 ?us confirm+ ! law t two bodies w attract ea* o!r 9 proportion to _! mass4 ,suppose1 n[1 t ^! balls are plac$ two in*es ap>t1--t is1 twice ! di/ance4 ,z ea* is1 we %all say1 f\r p\nds 9 weight1 ! squ>e ( ea* w\ld be #af4 ,?is does n mean t !re w\ld be sixte5 times ! attraction1 b1 z ! law says1 inv]sely z ! squ>e ( ! di/ance1 s t at two in*es !re is only "o-sixte5? ! attraction z at "o in*4 ,if ! cord ( "o ( ! balls %\ld be cut1 x w\ld fall to ! e>?1 = ! reason t ! attractive =ce ( ! great mass ( ! e>? is s mu* great] ?an ! =ce ( attraction 9 its companion ball4 ,,inde/ructibility ,,( ,,gravitation4--,gravity _c be produc$ or de/roy$4 ,x acts betwe5 all p>ts ( bodies equally2 ! =ce be+ proportion$ to _! mass4 ,x is n affect$ by any int]v5+ sub/ance2 & is transmitt$ in/antane\sly1 :atev] ! di/ance may be4 ,:ile1 !re=e1 x is impossible to dive/ matt] ( ?is prop]ty1 !re are two conditions :i* neutralize its effect4 ,! fir/ ( ^! is position4 ,let u take two balls1 "o solid & ! o!r holl[1 b ( ! same mass1 or d5sity4 ,if ! cavity ( ! "o is l>ge en\gh to receive ! o!r1 x is obvi\s t :ile gravity is /ill pres5t ! l9es ( attraction be+ equal at all po9ts1 & radially1 !re c be no pull :i* moves !m toge!r4 ,,di/ance ,,r$uces ,,gravitational ,,pull4--,or ! balls may be su* di/ance ap>t t ! attractive =ce ceases4 ,at ! c5t] ( ! e>? an object w\ld n weigh any?+4 ,a p\nd ( iron & an ounce ( wood1 "o sixte5 times ! mass ( ! o!r1 w\ld be ! same1--absolutely )\t weight4 ,if ! object %\ld be f> away 9 space x w\ld n be influ5c$ by ! e>?'s gravity2 s x w be und]/ood t position plays an important "p 9 ! attraction ( mass = mass4 ,,h[ ,,motion ,,antagonizes ,,gravity4--,! second way to neutralize gravity1 is by motion4 ,a ball ?r[n upw>dly1 antagonizes ! =ce ( gravity dur+ ! p]iod ( its asc5t4 ,9 l mann]1 :5 an object is project$ horizontally1 :ile its mass is /ill ! same1 its weight is less4 ,motion is t :i* is con/antly combat+ ! action ( gravity4 ,a body mov+ 9 a circle mu/ be act$ ^u by two =ces1 "o :i* t5ds to draw x inw>dly1 & ! o!r :i* seeks to ?r[ x outw>dly4 ,! =m] is call$ c5tripetal1 & ! latt] c5trifugal motion4 ,gravity1 !re=e1 repres5ts c5tripetal1 & motion c5trifugal =ce4 ,if ! rotative spe$ ( ! e>? %\ld be ret>d$1 all objects on ! e>? w\ld be increas$ 9 weight1 & if ! motion %\ld be accel]at$ objects w\ld become light]1 & if suffici5t spe$ %\ld be atta9$ all matt] w\ld fly (f ! surface1 j z dirt dies (f ! rim ( a :eel at c]ta9 spe$s4 ,a ,,tang5t4--,:5 an object is ?r[n horizontally ! l9e ( flight is tang5tial to ! e>?1 or at "r angles to ! =ce ( gravity4 ,su* a c\rse 9 a fly+ ma*9e f9ds less resi/ance ?an if x %\ld be project$ upw>dly1 or directly opposite ! c5tripetal pull4 ,fig #a4 ,tang5tial ,flight ,,tang5tial ,,motion ,,repres5ts ,,c5trifugal ,,pull4--,a tang5tial motion1 or a horizontal movem5t1 seeks to move matt] away f ! c5t] ( ! e>?1 & any =ce :i* imp>ts a horizontal motion to an object ex]ts a c5trifugal pull = t reason4 ,9 ,fig4 #a1 let ,a repres5t ! surface ( ! e>?1 ,b ! />t+ po9t ( ! flight ( an object1 & ,c ! l9e ( flight4 ,t repres5ts a tang5tial l9e4 ,= ! purpose ( expla9+ ! ph5om5a ( tang5tial flight1 we w assume t ! missile 0 project$ ) a suffici5t =ce to rea* ! v]tical po9t ,d1 :i* is #djjj miles f ! />t+ po9t ,b4 ,9 su* a case x w\ld n[ be ov] #eejj miles f ! c5t] ( ! e>?1 & ! c5trifugal pull w\ld be decreas$ to su* an ext5t t ! ball w\ld g on & on until x came )9 ! sph]e ( influ5ce f "s o!r cele/ial body4 ,,equaliz+ ,,! ,,two ,,motions4--,b n[ let u assume t ! l9e ( flight is l t %[n at ,e1 9 ,fig4 #b1 :]e x travels along p>allel ) ! surface ( ! e>?4 ,9 ?is case ! =ce ( ! ball equals ! c5tripetal pull1--or1 to put x diff]5tly1 ! c5trifugal equals ! gravitational pull4 ,! con/ant t5d5cy ( ! ball to fly (f at a tang5t1 & ! equally p[]ful pull ( gravity act+ aga9/ ea* o!r1 produce a motion :i* is l t ( ! e>?1 revolv+ ar\nd ! sun once e ?ree hundr$ & sixty-five days4 ,x is a curi\s ?+ t nei!r ,langley1 nor any ( ! sci5ti/s1 9 treat+ ( ! matt] ( flight1 h tak5 into consid]ation ?is quality ( mom5tum1 9 _! calculations ( ! elem5ts ( flight4 ,fig4 #b ,horizontal ,flight ,all h treat$ ! subject z ?\gh ! :ole problem re/$ on ! angle at :i* ! planes 7 plac$4 ,at #de degrees ! lift & drift are assum$ to be equal4 ,,lift ,,& ,,drift4--,! t]ms %\ld be expla9$1 9 view ( ! frequ5t allusion :i* w be made to ! t]ms h]e9aft]4 ,lift is ! ^w employ$ to indicate ! am\nt :i* a plane surface w support :ile 9 flight4 ,drift is ! t]m us$ to indicate ! resi/ance :i* is (f]$ to a plane mov+ =w>dly aga9/ ! atmosph]e4 ,fig4 #c4 ,lift & ,drift ,9 ,fig4 #c ! plane ,a is assum$ to be mov+ =w>dly 9 ! direction ( ! arr[ ,b4 ,?is indicates ! resi/ance4 ,! v]tical arr[ ,c %[s ! direction ( lift1 :i* is ! weight held up by ! plane4 ,,normal ,,pressure4--,n[ !re is ano!r t]m mu* us$ :i* ne$s explanation1 & t is normal pressure4 ,a pressure ( ?is k9d aga9/ a plane is :]e ! w9d /rikes x at "r angles4 ,?is is illu/rat$ 9 ,fig4 #d1 9 :i* ! plane is %[n ) ! w9d /rik+ x squ>ely4 ,x is obvi\s t ! w9d w ex]t a great] =ce aga9/ a plane :5 at its normal4 ,on ! o!r h&1 ! lea/ pressure aga9/ a plane is :5 x is 9 a horizontal position1 because !n ! w9d has no =ce aga9/ ! surfaces1 & ! only effect on ! drift is t :i* takes place :5 ! w9d /rikes its =w>d edge4 ,fig4 #d4 ,normal ,air ,pressure ,fig4 #e4 ,edge ,resi/ance ,,head ,,resi/ance4--,fig4 #e %[s su* a plane1 ! only resi/ance be+ ! ?ickness ( ! plane z at ,a4 ,?is is call$ head resi/ance1 & on ?is subject !re has be5 mu* controv]sy1 & _m !ories1 :i* w be consid]$ "u ! prop] head+s4 ,if a plane is plac$ at an angle ( #de degrees ! lift & ! drift are ! same1 assum$ly1 because1 if we 7 to measure ! p[] requir$ to drive x =w>dly1 x w\ld be f\nd to equal ! weight necess>y to lift x4 ,t is1 suppose we %\ld hold a plane at t angle ) a heavy w9d bl[+ aga9/ x1 & atta* two pairs ( scales to ! plane1 bo? w\ld %[ ! same pull4 ,fig4 #f4 ,measur+ ,lift & ,drift ,,measur+ ,,lift ,,& ,,drift4--,9 ,fig4 #f1 ,a is ! plane1 ,b ! horizontal l9e :i* atta*es ! plane to a scale ,c1 & ,d ! l9e atta*+ x to ! scale ,e4 ,:5 ! w9d is ( suffici5t =ce to hold up ! plane1 ! scales w %[ ! same pull1 neglect+1 ( c\rse1 ! weight ( ! plane itself4 ,,pressure ,,at ,,diff]5t ,,angles4--,:at e "o wants to "k1 & a subject on :i* a great deal ( exp]im5t & "t h be5 exp5d$1 is to det]m9e :at ! pressures are at ! diff]5t angles betwe5 ! horizontal1 & laws h be5 =mulat$ :i* enable ! pressures to be calculat$4 ,,diff]5ce ,,betwe5 ,,lift ,,& ,,drift ,,9 ,,motion4--,! fir/ obs]vation is direct$ to ! diff]5ces t exi/ betwe5 ! lift & drift1 :5 ! plane is plac$ at an angle ( less ?an #de degrees4 ,a ma*9e weigh+ #ajjj p\nds has always ! same lift4 ,its mass does n *ange4 ,rememb]1 n[1 we allude to its mass1 or d5sity4 ,we are n n[ ref]r+ to weight1 because t mu/ be tak5 into consid]ation1 9 ! problem4 ,z h]et(ore /at$1 :5 an object moves horizontally1 x has less weight ?an :5 at re/4 ,if x _h ! same weight x w\ld n move =w>dly1 b come to re/4 ,:5 9 motion1 !re=e1 :ile ! lift1 s f> z its mass is conc]n$1 does n *ange1 ! drift does decrease1 or ! =w>d pull is less ?an :5 at #de degrees1 & ! decrease is less & less until ! plane assumes a horizontal position1 :]e x is absolutely nil1 if we d n consid] head resi/ance4 ,,tables ,,( ,,lift ,,& ,,drift4--,all tables ( ,lift & ,drift consid] only ! air pressures4 ,!y d n take into acc\nt ! fact t mom5tum takes an important "p 9 ! translation ( an object1 l a fly+ ma*9e4 ,a mass ( mat]ial1 weigh+ #ajjj p\nds :ile at re/1 sets up an enorm\s en]gy :5 mov+ ?r\gh ! air at fifty1 sev5ty-five1 or "o hundr$ miles an h\r4 ,at ! latt] spe$ ! movem5t is ab\t #afj feet p] second1 a motion :i* is ne>ly suffici5t to ma9ta9 x 9 horizontal flight1 indep5d5tly ( any plane surface4 ,su* be+ ! case1 :y take into acc\nt only ! angle ( ! plane8 ,x is no wond] t aviators h n be5 able to make ! !oretical consid]ations & ! practical demon/rations agree4 ,,:y ,,tables ,,( ,,lift ,,& ,,drift ,,are ,,wrong4-- ,a little reflection w %[ :y su* tables are wrong4 ,!y 7 prep>$ by us+ a plane surface at re/1 & =c+ a bla/ ( air aga9/ ! plane plac$ at diff]5t angles2 & = det]m9+ air pressures1 ?is is1 no d\bt1 correct4 ,b x does n repres5t actual fly+ conditions4 ,x does n %[ ! conditions exi/+ 9 an a]oplane :ile 9 flight4 ,to det]m9e ?is1 %ort ( actual exp]im5ts ) a ma*9e 9 horizontal translation1 is impossible1 unless x is done by tak+ into acc\nt ! factor due to mom5tum & ! elem5t attributable to ! lift ( ! plane itself due to its impact aga9/ ! atmosph]e4 ,,langley',s ,,law4--,! law enunciat$ by ,langley is1 t ! great] ! spe$ ! less ! p[] requir$ to propel x4 ,wat] z a propell+ m$ium has ov] sev5 hundr$ times m =ce ?an air4 ,a vessel hav+1 = in/ance1 tw5ty horse p[]1 & a spe$ ( t5 miles p] h\r1 w\ld require f\r times t p[] to drive x ?r\gh ! wat] at d\ble ! spe$4 ,! p[] is z ! squ>e ( ! spe$4 ,) air ! conditions are entirely diff]5t4 ,! boat subm]g5ce 9 ! wat] is practically ! same1 :e!r go+ t5 or tw5ty miles an h\r4 ,! head resi/ance is ! same1 sub/antially1 at all times 9 ! case ( ! boat2 ) ! fly+ ma*9e ! resi/ance ( its su/a9+ surfaces decreases4 ,)\t go+ into a too te*nical description ( ! reason+ :i* l$ to ! discov]y ( ! law ( air pressures1 let u try & und]/& x by exam9+ ! diagram1 ,fig4 #g4 ,a repres5ts a plane at an angle ( #de degrees1 mov+ =w>dly into ! atmosph]e 9 ! direction ( ! arr[s ,b4 ,! measurem5t across ! plane v]tically1 along ! l9e ,b1 :i* is call$ ! s9e ( ! angle1 repres5ts ! surface impact ( air aga9/ ! plane4 ,9 ,fig4 #h ! plane is at an angle ( #bg degrees1 :i* makes ! di/ance 9 height across ! l9e ,c j "o-half ! l5g? ( ! l9e ,b ( ,fig4 #g1 h5ce ! surface impact ( ! air is "o-half t ( ,fig4 #g1 & ! drift is correspond+ly decreas$4 ,fig4 #g4 ,equal ,lift & ,drift 9 ,flight4 ,fig4 #h4 ,unequal ,lift & ,drift4 ,,mov+ ,,planes ,,vs4 ,,w9ds4--,9 ?is way ,boisset1 ,du*em91 ,langley1 & o!rs1 det]m9$ ! comp>ative drift1 & ^? results h be5 l>gely reli$ ^u by aviators1 & assum$ to be correct :5 appli$ to fly+ ma*9es4 ,t !y are n correct has be5 prov5 by ! ,wrights & o!rs1 ! only explanation be+ t "s errors _h be5 made 9 ! calculations1 or t aviators 7 liable to commit errors 9 obs]v+ ! true angle ( ! planes :ile 9 flight4 ,,mom5tum ,,n ,,consid]$4--,! great factor ( mom5tum has be5 entirely ignor$1 & x is our desire to press ! important po9t on ^? :o beg9 to /udy ! "q ( fly+ ma*9es4 ,,! ,,flight ,,( ,,birds4--,volumes h be5 writt5 conc]n+ obs]vations on ! flight ( birds4 ,! m>vel has be5 :y d so>+ birds ma9ta9 !mselves 9 space )\t flapp+ _! w+s4 ,9 fact1 x is a mu* m rem>kable ?+ to contemplate :y birds :i* dep5d on flapp+ w+s c fly4 ,,! ,,d[nw>d ,,beat4--,x is argu$ t ! d[nw>d beat ( ! w+s is s mu* m rapid ?an ! upw>d motion1 t x gets an action on ! air s z to =ce ! body upw>dly4 ,?is is dispos$ ( by ! w+ motion ( _m birds1 notori\sly ! cr[1 ^: lazily-flapp+ w+s c be readily foll[$ by ! eye1 & ! diff]5ce 9 movem5t1 if any1 is n p]ceptible4 ,,! ,,concav$ ,,w+4--,x is also urg$ t ! concave on ! "u side ( ! w+ gives ! quality ( lift4 ,c]ta9 k9ds ( beetles1 & p>ticul>ly ! common h\se fly1 disprove t !ory1 z _! w+s are p]fectly flat4 ,,fea!r ,,/ructure ,,consid]$4--,!n ! fea!r argum5t is advanc$1 :i* seeks to %[ t z ea* w+ is made up ( a plurality ( fea!rs1 ov]lapp+ ea* o!r1 !y =m a sort ( a valv$ surface1 op5+ s z to p]mit air to pass ?r\gh !m dur+ ! p]iod ( _! upw>d movem5t1 & clos+ up z ! w+ desc5ds4 ,x is difficult to p]=m ?is exp]im5t ) w+s1 s z to %[ su* an individual fea!r movem5t4 ,x is c]ta9 t !re is no?+ 9 ! /ructure ( ! w+ bone & ! fea!r connection :i* po9ts to any individual fea!r movem5t1 & our obs]vation is1 t ea* fea!r is entirely too rigid to p]mit ( su* an op5+ up betwe5 !m4 ,x is obvi\s t ! w+ is built up 9 t way = an entirely diff]5t reason4 ,so>+ birds1 :i* d n dep5d on ! flapp+ motion1 h ! same ov]lapp+ fea!r =mation4 ,,webb$ ,,w+s4--,fur!rmore1 !re are num]\s fly+ creatures :i* d n h fea!r$ w+s1 b web-l /ructures1 or l ! h\se fly1 9 "o cont9u\s & unbrok5 plane4 ,t birds :i* fly ) flapp+ w+s d]ive _! support f ! air1 is und\bt$ly true1 & t ! lift produc$ is due1 n to ! =m1 or %ape1 or area ( ! w+1 is also beyond "q4 ,! records %[ t e conceivable type ( outl9$ /ructure is us$ by nature2 ! mat]ial & texture ( ! w+s !mselves diff] to su* a degree t !re is absolutely no simil>ity2 "s h concav$ "u surfaces1 & o!rs h n2 "s fly ) rapidly beat+ w+s1 & o!rs ) sl[ & measur$ movem5ts2 _m ( !m fly ) equal facility )\t flapp+ movem5ts2 & ! proportions ( weight to w+ surface v>y to su* an ext5t t x is utt]ly impossible to use su* data z a guide 9 calculat+ :at ! prop] surface %\ld be = a correct fly+ ma*9e4 ,,! ,,angle ,,( ,,movem5t4--,h[1 !n1 x may be ask$1 d !y get _! support8 ,!re mu/ be some?+1 9 all ?is v>iety & div]sity ( =m1 ( motion1 & ( *>act]i/ics1 :i* supplies ! true answ]4 ,! answ] lies 9 ! angle ( movem5t ( e w+ motion1 :i* is at ! control ( ! bird1 & if ?is is exam9$ x w be f\nd t x supplies ! correct answ] to e type ( w+ :i* nature has made4 ,,an ,,initial ,,impulse ,,or ,,movem5t ,,necess>y4-- ,let ,a1 ,fig4 #i1 repres5t ! section ( a bird's w+4 ,all birds1 :e!r ( ! so>+ or ! flapp+ k9d1 mu/ h an initial =w>d movem5t 9 ord] to atta9 flight4 ,?is impulse is acquir$ ei!r by runn+ along ! gr\nd1 or by a leap1 or 9 dropp+ f a p]*4 ,so>+ birds _c1 by any possibility1 beg9 flight1 unless !re is su* a movem5t to *ange f a position ( re/ to "o ( motion4 ,fig4 #i4 ,w+ ,movem5t 9 ,flight4 ,9 ! diagram1 !re=e1 ! bird1 9 mov+ =w>dly1 :ile rais+ ! w+ upw>dly1 depresses ! re> edge ( ! w+1 z 9 position #a1 & :5 ! w+ beats d[nw>dly ! re> m>g9 is rais$1 9 relation to its front m>g91 z %[n 9 position #b4 ,a ,,w$g+ ,,motion4--,?us ! bird1 by a w$ge-l motion1 gives a =w>dly-propell+ action1 & z ! re> m>g9 has m or less flexure1 its action aga9/ ! air is less dur+ its upw>d beat1 & ?is also adds to ! upw>d lift ( ! body ( ! bird4 ,,no ,,my/]y ,,9 ,,! ,,wave ,,motion4--,!re is no my/]y 9 ! effect ( su* a wave-l motion1 & x mu/ be obvi\s t ! humm+ bird1 & l fly]s1 :i* poise at "o spot1 are able to d s because1 in/ead ( mov+ =w>dly1 or *ang+ ! position ( its body horizontally1 9 p]=m+ ! undulatory motion ( ! w+1 x causes ! body to rock1 s t at ! po9t :]e ! w+ jo9s ! body1 an elliptical motion is produc$4 ,fig4 #aj4 ,evolution ( ,humm+-,bird's ,w+4 ,,h[ ,,birds ,,poise ,,) ,,flapp+ ,,w+s4--,?is is %[n 9 ,fig4 #aj1 9 :i* eight successive positions ( ! w+ are %[n1 & :]e9 f\r ( ! position1 namely1 #a1 #b1 #c1 & #d1 repres5t ! d[nw>d movem5t1 & #f1 #g1 #h1 & #i1 ! upw>d beat4 ,all ! w+ angles are su* t :e!r ! susp5sion po9t ( ea* w+ is mov+ d[nw>dly1 or upw>dly1 a support is f\nd 9 "s "p ( ! w+4 ,,n>r[-,,w+$ ,,birds4--,birds ) rapid flapp+ motions h comp>atively n>r[ w+s1 =e & aft4 ,^? :i* flap sl[ly1 & are n swift fly]s1 h correspond+ly broad] w+s4 ,! broad w+ is also typical ( ! so>+ birds4 ,b h[ d ! latt] ov]come gravitation )\t ex]cis+ "s sort ( w+ movem5t8 ,,initial ,,movem5t ,,( ,,so>+ ,,birds4--,acute obs]vations %[ t dur+ ! e>ly /ages ( flight1 be=e spe$ is acquir$1 !y dep5d on ! undulat+ movem5t ( ! w+s1 & "s ( !m acquire ! initial motion by flapp+4 ,:5 spe$ is f9ally atta9$ x is difficult = ! eye to note ! motion ( ! w+s4 ,,so>+ ,,birds ,,move ,,swiftly4--,n[1 ! fir/ obs]vation is1 t so>+ birds are swiftly- mov+ creatures4 ,z !y sail ov]head maje/ically !y seem to be mov+ sl[ly4 ,b di/ance is deceptive4 ,! so>+ bird travels at great spe$s1 & ?is 9 itself %\ld be suffici5t to enable u to cease wond]+1 :5 x is rememb]$ t swift translation decreases weight1 s t ?is factor does n1 "u ^? conditions1 op]ate aga9/ flight4 ,,muscul> ,,en]gy ,,ex]t$ ,,by ,,so>+ ,,birds4 --,x is n conceivable t ! m]e w ( ! bird w\ld impel x =w>dly1 )\t x ex]t$ "s muscul> en]gy to keep up its spe$4 ,! di/ance at :i* ! bird p]=ms ?is wond]ful evolution is at su* heights f ! obs]v] t ! eye _c detect a movem5t4 ,,w+s ,,n ,,motionless4--,:ile ! w+s appe> to be absolutely motionless1 x is m reasonable to assume t a slight s9u\s movem5t1 or a rock+ motion is con/antly kept up1 :i* w$ges =w>dly ) suffici5t spe$ to compel mom5tum to ma9ta9 x 9 flight4 ,to d s requires b a small am\nt ( en]gy4 ,! head resi/ance ( ! bird =mation is r$uc$ to a m9imum1 & at su* high spe$s ! angle ( incid5ce ( ! w+s is v small1 requir+ b little aid to ma9ta9 x 9 horizontal flight4 ,,*apt] ,,ii ,,pr9ciples ,,( ,,a]oplane ,,flight ,,f ! =ego+ *apt]1 :ile x may be rightly inf]r$ t p[] is ! true secret ( a]oplane flight1 x is desirable to po9t out c]ta9 o!r ?+s :i* mu/ be consid]$4 ,,spe$ ,,z ,,"o ,,( ,,! ,,elem5ts--,e boy1 probably1 has at "s "t or o!r ?r[n small flat /ones1 call$ skipp]s4 ,he has notic$ t if !y are p>ticul>ly ?91 & l>ge 9 diamet]1 t !re is a peculi> sail+ motion1 & t !y move ?r\gh ! air 9 an undulat+ or wave-l pa?4 ,two ?+s contribute to ?is motion2 "o is ! size ( ! skipp]1 relative to its weight1 & ! o!r is its spe$4 ,if ! spe$ is sl[ x w quickly w5d its way to ! e>? 9 a gradual curve4 ,?is curv$ l9e is call$ its trajectory4 ,if x is n v l>ge diametrically1 9 proportion to its weight1 x w also make a gradual curve 9 desc5d+1 )\t skimm+ up & d[n 9 its flight4 ,,%ape ,,& ,,spe$4--,x has be5 obs]v$1 also1 t a r\nd ball1 or an object n flatt5$ out1 w make a regul> curv$ pa?1 :atev] ! spe$ may be4 ,x may be assum$1 !re=e1 t ! %ape alone does n acc\nt = ?is s9u\s motion2 b t spe$ is ! elem5t :i* acc\nts = x4 ,su* be+ ! case x may be well to inquire into ! peculi> action :i* causes a skipp] to d>t up & d[n1 & :y ! pa? ?us =m$ gr[s m & m acc5tuat$ z ! spe$ increases4 ,z w be m fully describ$ 9 a lat] *apt]1 ! impact ( air aga9/ a mov+ body does n increase 9 proportion to its spe$1 b 9 ! ratio ( ! squ>e ( ! spe$4 ,,:at ,,squ>e ,,( ,,! ,,spe$ ,,means4--,9 ma!matics a figure is squ>$ :5 x is multipli$ by itself4 ,?us1 #d ,x #d #af2 #e ,x #e #be2 & s on1 s t #af is ! squ>e ( #d1 & #be ! squ>e ( #e4 ,x has be5 f\nd t a w9d mov+ at ! spe$ ( #bj miles an h\r has a /rik+ or pu%+ =ce ( #b p\nds on e squ>e foot ( surface4 ,if ! w9d travels twice z fa/1 or #dj miles an h\r1 ! pu%+ =ce is n #d p\nds1 b #h p\nds4 ,if ! spe$ is #fj miles an h\r ! pu%+ =ce increases to #ah p\nds4 ,,action ,,( ,a ,,skipp]4--,:5 ! skipp] leaves ! h&s ( ! ?r[] x goes ?r\gh ! air 9 su* a way t its fiat surface is absolutely on a l9e ) ! direction 9 :i* x is project$4 ,at fir/ x moves ?r\gh ! air solely by =ce ( ! p[] :i* impels x1 & does n 9 any way dep5d on ! air to hold x up4 ,see ,fig4 #a1 9 :i* ,a repres5ts ! l9e ( projection1 & ,b ! disk 9 its flight4 ,fig4 #aa4 ,a ,skipp] 9 ,flight4 ,aft] x has travel$ a c]ta9 di/ance1 & ! =ce decreases1 x beg9s to desc5d1 ?us describ+ ! l9e ,c1 ,fig4 #a1 ! disk ,b1 9 ?is case desc5d+1 )\t *ang+ its position1 :i* might be describ$ by say+ t x m]ely settles d[n to ! e>? )\t *ang+ its plane4 ,! skipp] /ill rema9s horizontal1 s t z x moves t[>d ! e>? its flat surface1 :i* is n[ expos$ to ! action ( ! air1 meets ) a resi/ance1 & ?is *anges ! angle ( ! disk1 s t x w n be horizontal4 ,in/ead x assumes ! position z indicat$ at ,d1 & ?is imp++ effect aga9/ ! air causes ! skipp] to move upw>dly along ! l9e ,e1 & hav+ rea*$ a c]ta9 limit1 z at1 say ,e1 x automatically aga9 *anges its angle & moves d[nw>dly along ! pa? ,f1 & ?us cont9ues to undulate1 m or less1 dep5d5t on ! comb9$ action ( ! p[] & weight1 or mom5tum1 until x rea*es ! e>?4 ,x is1 !re=e1 cle> t ! atmosph]e has an action on a plane surface1 & t ! ext5t ( ! action1 to su/a9 x 9 flight1 dep5ds on two ?+s1 surface & spe$4 ,fur!rmore1 ! great] ! spe$ ! less ! necessity = surface1 & t = glid+ purposes spe$ may be sacrific$1 9 a l>ge measure1 :]e !re is a l>ge surface4 ,?is v action ( ! skipp] is utiliz$ by ! aviator 9 volplan+1--t is1 :]e ! p[] ( ! eng9e is cut (f1 ei!r by accid5t1 or design$ly1 & ! ma*9e desc5ds to ! e>?1 :e!r 9 a long /raight glide1 or 9 a great circle4 ,z ! ma*9e ne>s ! e>? x is caus$ to *ange ! angle ( flight by ! control me*anism s t x w d>t upw>dly at an angle1 or d[nw>dly1 & ?us enable ! pilot to sail to ano!r po9t beyond :]e he may safely l&4 ,?is *ang+ ! c\rse ( ! ma*9e s t x w glide upw>dly1 means t ! incid5ce ( ! planes has be5 *ang$ to a positive angle4 ,,angle ,,( ,,incid5ce4--,9 aviation ?is is a t]m giv5 to ! position ( a plane1 relative to ! air aga9/ :i* x imp+es4 ,if1 = in/ance1 an a]oplane is mov+ ?r\gh ! air ) ! front m>g9 ( ! planes high] ?an _! re> m>g9s1 x is said to h ! planes at a positive angle ( incid5ce4 ,if ! re> m>g9s are high] ?an ! front1 !n ! planes h a negative angle ( incid5ce4 ,! ^w incid5ce really means1 a fall+ ^u1 or aga9/2 & x w be se51 !re=e1 t ! angle ( incid5ce means ! tilt ( ! planes 9 relation to ! air :i* /rikes x4 ,hav+ 9 view1 !re=e1 t ! two qualities1 namely1 spe$ & surface1 be> an intimate relation ) ea* o!r1 x may be und]/ood :]e9 me*anical flight is suppos$ to be analog\s to bird flight4 ,,spe$ ,,& ,,surface4--,birds :i* poise 9 ! air1 l ! humm+ bird1 d s because !y beat _! w+s ) great rapidity4 ,^? :i* so>1 z /at$1 c d s only by mov+ ?r\gh ! atmosph]e rapidly1 or by hav+ a l>ge w+ spread relative to ! weight4 ,x w ?us be se5 t spe$ & surface become ! controll+ factors 9 flight1 & t :ile ! latt] may be entirely elim9at$ f ! problem1 spe$ is absolutely necess>y "u any & all conditions4 ,by spe$ 9 ?is connection is n meant high velocity1 b t a movem5t1 produc$ by p[] express$ 9 "s =m1 is ! sole & mo/ necess>y requisite to movem5t ?r\gh ! air ) all heavi]-?an-air ma*9es4 ,if suffici5t p[] c be appli$ to an a]oplane1 surface is ( no consequ5ce2 %ape ne$ n be consid]$1 & any sort ( contrivance w move ?r\gh ! air horizontally4 ,,control ,,( ,,! ,,direction ,,( ,,flight4--,b ! control ( su* a body1 :5 propell$ ?r\gh space by =ce alone1 is a diff]5t matt]4 ,to *ange ! ma*9e f a /raight pa? to a curv$ "o1 means t x mu/ be act$ ^u by "s ext]nal =ce4 ,we h expla9$ t p[] is some?+ :i* is inh]5t 9 ! ?+ itself4 ,n[1 9 ord] t !re may be a *ange imp>t$ to a mov+ mass1 advantage mu/ be tak5 ( ! m$ium ?r\gh :i* x moves1--! atmosph]e4 ,,v]tical ,,control ,,planes4--,if v]tically-arrang$ planes are provid$1 ei!r =e or aft ( ! ma*9e1 or at bo? ends1 ! angles ( incid5ce may be su* z to cause ! ma*9e to turn f its /raight c\rse4 ,9 practice1 !re=e1 s9ce x is difficult to supply suffici5t p[] to a ma*9e to keep x 9 motion horizontally1 at all times1 a]oplanes are provid$ ) support+ surfaces1 & ?is aid 9 hold+ x up gr[s less & less z its spe$ increases4 ,b1 h[ev] /rong ! p[]1 or great ! spe$1 its control f side to side is n dep5d5t on ! p[] ( ! eng9e1 or ! spe$ at :i* x travels ?r\gh ! air4 ,"h ! size ( ! v]tical planes1 & _! angles1 are ! only factors to be consid]$1 & ^! que/ions w be consid]$ 9 _! prop] places4 ,,*apt] ,,iii ,,! ,,=m ,,or ,,%ape ,,( ,,fly+ ,,ma*9es ,,e inve/igator1 exp]im5t]1 & sci5ti/1 :o has giv5 ! subject ( flight /udy1 proce$s on ! !ory t 9 ord] to fly man mu/ copy nature1 & make ! ma*9e simil> to ! type s provid$4 ,,! ,,!ory ,,( ,,copy+ ,,nature4--,if su* is ! case !n x is p]t95t to inquire :i* bird is ! prop] example to use = me*anical flight4 ,we h %[n t !y diff] s radically 9 e ess5tial1 t :at w\ld be correct 9 "o ?+ w\ld be entirely wrong 9 ano!r4 ,! bi-plane is c]ta9ly n a true copy4 ,! only ?+ 9 ! ,wright ma*9e :i* 9 any way resembles ! bird's w+1 is ! r\nd$ end ( ! planes1 & judg+ f o!r ma*9es1 :i* h squ>e ends1 ?is slight simil>ity does n contribute to its /ability or o!rwise help ! /ructure4 ,! monoplane1 :i* is mu* ne>] ! bird type1 has also s\nd$ w+ ends1 made n s mu* = ! purpose ( imitat+ ! w+ ( ! bird1 z = /ructural reasons4 ,,hulls ,,( ,,vessels4--,if "s m>9e ar*itect %\ld come =w>d & ass]t t he int5d$ to foll[ nature by mak+ a boat ) a hull ( ! %ape or outl9e ( a duck1 or o!r swimm+ f[l1 he w\ld be laugh$ at1 & ju/ly s1 because ! l9es ( vessels :i* are mo/ effici5t are n made l ^? ( a duck or o!r swimm+ creatures4 ,,man ,,does ,,n ,,copy ,,nature4--,look ab\t y1 & see h[ _m me*anical devices foll[ ! =ms laid d[n by nature1 or 9 :at respect man uses ! types :i* nature provides 9 devis+ ! _m inv5tions :i* +5uity has br\ght =?4 ,,pr9ciples ,,ess5tial1 ,,n ,,=ms4--,x is ess5tial t man %all foll[ nature's laws4 ,he _c evade ! pr9ciples on :i* ! op]ations ( me*anism dep5d2 b 9 do+ s he has1 9 ne>ly e in/ance1 dep>t$ f ! =m :i* nature has sugge/$1 & made ! ma*9e irrespective ( nature's type4 ,let u consid] "s ( ^! /rik+ diff]5ces to illu/rate ?is fact4 ,orig9ally p9s 7 /uck ^u a pap] web by h&1 & plac$ 9 r[s1 equidi/ant f ea* o!r4 ,?is necessitates ! coop]ative function ( ! f+]s & ! eye4 ,an exp]t p9 /ick] c\ld ?us assemble f f\r to five ?\s& p9s a day4 ,! fir/ me*anical p9/ick] plac$ ov] #ejj1jjj p9s a day on ! web1 reject+ e b5t or headless p91 & did ! "w ) great] accuracy ?an x 0 possible to d x by h&4 ,!re 0 n ! sugge/ion ( an eye1 or a f+] 9 ! entire ma*9e1 to %[ t nature furni%$ ! type4 ,,nature ,,n ,,! ,,guide ,,z ,,to ,,=ms4--,nature does n furni% a :eel 9 any ( its me*anical expressions4 ,if man foll[$ nature's =m 9 ! build+ ( ! locomotive1 x w\ld move along on f\r legs l an elephant4 ,curi\sly en\gh1 "o ( ! fir/ road wagons _h pu% legs1--an in/ance :]e ! me*anic tri$ to copy nature1--& fail$4 ,,! ,,propell] ,,type4--,! well kn[n propell] is a type ( :eel :i* has no prototype 9 nature4 ,x is ma9ta9$ t ! tail ( a fi% 9 its movem5t sugge/$ ! propell]1 b ! latt] is a long dep>ture f x4 ,! ,v5etian r[]1 :o /&s at ! /]n1 & ) a long-blad$ o>1 fulcrum$ to ! boat's extremity1 9 mak+ 8 graceful lat]al oscillations1 simulates ! propell+ motion ( ! tail 9 an absolutely p]fect mann]1 b x is n a propell]1 by any means comp>able to ! k9d m\nt$ on a %aft1 & revoluble4 ,h[ mu* m effici5t are ! spirally-=m$ blades ( ! propell] ?an any w+ or f9 movem5t1 9 air or sea4 ,!re is no comp>ison betwe5 ! two =ms 9 utility or value4 ,aga91 ! connect+ po9ts ( ! arms & legs ) ! trunk ( a human body af=d ! mo/ p]fect types ( univ]sal jo9ts :i* nature has produc$4 ,! man-made univ]sal jo9t has a wid] range ( movem5t1 possesses great] /r5g?1 & is m p]fect me*anically4 ,a univ]sal jo9t is a piece ( me*anism betwe5 two elem5ts1 :i* enables !m to be turn$1 or mov$1 at any angle relative to ea* o!r4 ,b :y multiply ^! in/ances4 ,l samples w be f\nd on e h&1 & 9 all directions1 & man1 ! greate/ ( all ( nature's products1 :ile imp]fect 9 himself1 is improv+ & adapt+ ! ?+s he sees ab\t him4 ,,:y ,,specially-,,design$ ,,=ms ,,improve ,,natural ,,/ructures4--,! reason = ?is is1 prim>ily1 t ! inv5tor mu/ design ! article = its special "w1 & 9 do+ s makes x bett] adapt$ to d t p>ticul> ?+4 ,! h&s & f+]s c d a multiplicity ( ?+s1 b x _c d any p>ticul> "w ) ! facility or ! degree ( p]fection t is possible ) ! ma*9e made = t purpose4 ,! h&s & f+]s w b9d a %eaf ( :eat1 b x _c compete ) ! special ma*9e made = t purpose4 ,on ! o!r h& ! b9d] has no capacity to d any?+ else ?an :at x 0 specially made =4 ,9 apply+ ! same sort ( reason+ to ! build+ ( fly+ ma*9es we mu/ be l$ to ! conclusion t ! inv5tor c1 & w1 ev5tually1 br+ out a =m :i* is z f> sup]ior to ! =m :i* nature has taught u to use z ! wond]ful ma*9es we see all ab\t u are sup]ior to c>ry out ! special "w !y 7 design$ to d4 ,on l&1 man has %[n ?is sup]iority ov] matt]1 & s on ! sea4 ,s+ul>ly1 ! subm>9es1 :i* g b5ea? ! sea1 are v f> f t p]fect$ /ate :i* h be5 atta9$ by vessels sail+ on ! surface2 & :ile ! means ( transportation on l& are arriv+ at po9ts :]e ! developm5ts are swift & rem>kable1 ! space above ! e>? has n yet be5 conqu]$1 b is go+ ?r\gh t same p]iod ( developm5t :i* prec$es ! production ( ! true =m itself4 ,,me*anism ,,devoid ,,( ,,intellig5ce4--,! great error1 h[ev]1 9 seek+ to copy nature's =m 9 a fly+ ma*9e is1 t we _c inve/ ! me*anism ) t :i* ! bird has1 namely1 a guid+ intellig5ce to direct x in/9ctively1 z ! fly+ creature does4 ,a ,,ma*9e ,,mu/ ,,h ,a ,,sub/itute ,,= ,,intellig5ce4 --,su* be+ ! case x mu/ be end[$ ) some?+ :i* is a sub/itute4 ,a bird is a supple1 pliant organism2 a ma*9e is a rigid /ructure4 ,"o is capable ( be+ direct$ by a m9d :i* is a "p ( ! ?+ itself2 :ile ! o!r mu/ dep5d on an intellig5ce :i* is sep>ate f x1 & n responsive 9 feel+ or movem5t4 ,= ! =ego+ reasons success c nev] be atta9$ until "s /ructural =m is devis$ :i* w consid] ! fly+ ma*9e indep5d5tly ( ! prototypes po9t$ out z ! correct ?+s to foll[4 ,x does n1 necess>ily1 h to be unlike ! bird =m1 b we d "k t ! pres5t /ructures h be5 made & insi/$ ^u bl9dly1 because ( ?is wrong insi/5ce on =ms4 ,,/udy ,,( ,,bird ,,flight ,,useless4--,! /udy ( ! flight ( birds has nev] be5 ( any special value to ! art4 ,volumes h be5 writt5 on ! subject4 ,! ,sev5? ,duke ( ,argyle1 & lat]1 ,pettigrew1 an ,engli%man1 contribut$ a va/ am\nt ( writt5 matt] on ! subject ( bird flight1 9 :i* x 0 s\ght to %[ t so>+ birds did n ex]t any p[] 9 fly+4 ,writ]s & exp]im5t]s d n agree on ! "q ( ! propulsive p[]1 or on ! =m or %ape ( ! w+ :i* is mo/ effective1 or 9 ! matt] ( ! relation ( surface to weight1 nor d !y agree 9 any p>ticul> z to ! effect & action ( matt] 9 ! so>+ pr9ciple4 ,only a small p]c5tage ( fly+ creatures use motionless w+s z 9 so>+4 ,by f>1 ! great] majority use beat+ w+s1 a me?od ( translation 9 air :i* has n met ) success 9 any attempts on ! "p ( ! inv5tor4 ,nev]!less1 exp]im5t+ has proce$$ on l9es :i* seek to recognize nature's =m only1 :ile avoid+ ! be/ kn[n & mo/ p]si/5t type4 ,,%ape ,,( ,,support+ ,,surfaces4--,:5 we exam9e ! prevail+ type ( support+ surfaces we _c fail to be impress$ ) "o feature1 namely1 ! det]m9ation to insi/ on a broad spread ( plane surface1 9 imitation ( ! bird ) out/ret*$ w+s4 ,,! ,,tr\ble ,,aris+ ,,f ,,out/ret*$ ,,w+s4--,?is =m ( con/ruction is :at br+s all ! tr\bles 9 its tra94 ,! lit]ature on aviation is full ( argum5ts on ?is subject1 all decl>+ t a wide spread is ess5tial1 because1 --birds fly t way4 ,^! ass]tions are made not)/&+ ! fact t only a few ye>s ago1 9 ! great exhibit ( a]oplanes 9 ,p>is1 _m unique =ms ( ma*9es 7 %[n1 all ( !m capable ( fly+1 z prov5 by num]\s exp]im5ts1 & among !m 7 a half doz5 types ^: l5g? =e & aft 7 mu* great] ?an transv]sely1 & x 0 p>ticul>ly not$ t !y _h mo/ wond]ful /ability4 ,,d5sity ,,( ,,! ,,atmosph]e4--,exp]ts decl>e t ! d5sity ( ! atmosph]e v>ies ?r\gh\t1 --t x has spots "h & !re :i* are1 app>5tly1 l holes1 s t "o side or ! o!r ( ! ma*9e w1 unacc\ntably1 tilt1 & sometimes ! entire ma*9e w sudd5ly drop = _m feet1 :ile 9 flight4 ,,ela/icity ,,( ,,! ,,air4--,air is ! mo/ ela/ic sub/ance kn[n4 ,! p>ticles con/itut+ x are con/antly 9 motion4 ,:5 heat or cold p5etrate ! mass x does s1 9 a g5]al way1 s z to p]meate ! entire body1 b ! conductivity ( ! atmosph]ic gases is su* t ! heat does n rea* all p>ts at ! same "t4 ,,air ,,holes4--,! result is t v>y+ /rata ( heat & cold seem to be sup]pos$1 & also di/ribut$ along ! r\te tak5 by a ma*9e1 caus+ air curr5ts :i* v>y 9 direction & int5sity4 ,:51 !re=e1 a rapidly-mov+ ma*9e passes ?r\gh an atmosph]e s di/urb$1 ! surfaces ( ! planes /rike a mass ( air mov+1 we may say1 fir/ t[>d ! plane1 & ! next in/ant ! curr5t is rev]s$1 & ! ma*9e drops1 because its support is tempor>ily gone1 & ! aviator exp]i5ces ! s5sation ( go+ into a hole4 ,,responsibility ,,= ,,accid5ts4--,^! s-call$ holes are responsible = _m accid5ts4 ,! out/ret*$ w+s1 _m ( !m ov] =ty feet f tip to tip1 (f] opportunities = a tilt at "o end or ! o!r1 :i* has s5t s _m ma*9es to de/ruction4 ,! high c5t] ( gravity 9 all ma*9es makes ! weight useless to c\nt]balance ! ris+ end or to hold up ! depress$ w+4 ,all aviators agree t ^! unequal areas ( d5sity ext5d ov] small spaces1 & x is1 !re=e1 obvi\s t a ma*9e :i* is ( su* a /ructure t x moves ?r\gh ! air broadside on1 w be m liable to meet ^! inequalities ?an "o :i* is n>r[ & does n take 9 su* a wide pa?4 ,:y1 !re=e1 p]si/ 9 mak+ a =m :i*1 by its v nature1 invites dang]8 ,because birds fly t way6 ,,! ,,turn+ ,,movem5t4--,?is /ructural arrangem5t acc5tuates ! difficulty :5 ! ma*9e turns4 ,! air pressure aga9/ ! w+ surface is dep5d5t on ! spe$4 ,! broad out/ret*$ surfaces compel ! w+ at ! out] side ( ! circle to travel fa/] ?an ! inn] "o4 ,z a result1 ! out] end ( ! a]oplane is elevat$4 ,,c5trifugal ,,action4--,at ! same "t ! runn+ ge>1 & ! frame :i* c>ries x & supports ! ma*9e :ile at re/1 be+ bel[ ! planes1 a c5trifugal =ce is ex]t$1 :5 turn+ a circle1 :i* t5ds to sw+ ! :eels & frame outw>dly1 & !reby /ill fur!r elevat+ ! out] end ( ! plane4 ,,! ,,w>p+ ,,planes4--,! only rem$y to meet ?is condition is express$ 9 ! me*anism :i* wraps or twi/s ! out] ends ( ! planes1 z con/ruct$ 9 ! ,wright ma*9e1 or ! ail]ons1 or small w+s at ! re> m>g9s ( ! planes1 z illu/rat$ by ! ,f>man ma*9e4 ,! object ( ?is arrangem5t is to decrease ! angle ( incid5ce at ! ris+ end1 & increase ! angle at ! depress$ end1 & ?us1 by manually- op]at$ means keep ! ma*9e on an ev5 keel4 ,,*apt] ,,iv ,,=e ,,& ,,aft ,,control ,,!re is no phase ( ! art ( fly+ m important ?an ! =e & aft control ( an air%ip4 ,lat]al /ability is second>y to ?is feature1 = reasons :i* w appe> z we develop ! subject4 ,,! ,,bird ,,type ,,( ,,=e ,,& ,,aft ,,control4-- ,e a]oplane foll[s ! type set by nature 9 ! p>ticul> t ! body is caus$ to oscillate on a v]tical =e & aft plane :ile 9 flight4 ,! bird has "o important advantage1 h[ev]1 9 /ructure4 ,its w+ has a flexure at ! jo9t1 s t its body c s oscillate indep5d5tly ( ! angle ( ! w+s4 ,! a]oplane has ! w+ firmly fix$ to ! body1 h5ce ! only way 9 :i* x is possible to effect a *ange 9 ! angle ( ! w+ is by *ang+ ! angle ( ! body4 ,to be consi/5t ! a]oplane %\ld be s con/ruct$ t ! angle ( ! support+ surfaces %\ld be movable1 & n controllable by ! body4 ,! bird1 9 initiat+ flight f a p]*1 d>ts d[nw>dly1 & *anges ! angle ( ! body to correspond ) ! direction ( ! fly+ />t4 ,:5 x alights ! body is ?r[n s t its brea/ banks aga9/ ! air1 b 9 ord9>y flight its w+s only are us$ to *ange ! angle ( flight4 ,,angle ,,& ,,direction ,,( ,,flight4--,9 ord] to become famili> ) t]ms :i* w be frequ5tly us$ ?r\gh\t ! book1 c>e %\ld be tak5 to di/+ui% betwe5 ! t]ms angle & direction ( flight4 ,! =m] has ref]5ce to ! up & d[n movem5t ( an a]oplane1 :]eas ! latt] is us$ to designate a turn+ movem5t to ! "r or to ! left4 ,,:y ,,%\ld ,,! ,,angle ,,( ,,! ,,body ,,*ange8 --,! fir/ "q t pres5ts itself is1 :y %\ld ! angle ( ! a]oplane body *ange8 ,:y %\ld x be made to d>t up & d[n & produce a s9u\s motion8 ,:y %\ld its nose tilt t[>d ! e>?1 :5 x is desc5d+1 & raise ! =w>d "p ( ! /ructure :ile asc5d+8 ,! ready answ] on ! "p ( ! bird-=m advocate is1 t nature has s design$ a fly+ /ructure4 ,! argum5t is n consi/5t1 because 9 ?is respect1 z 9 e o!r1 x is n made to con=m to ! /ructure :i* !y seek to copy4 ,,*ang+ ,,angle ,,( ,,body ,,n ,,safe4--,fur!rmore1 !re is n a s+le argum5t :i* c be advanc$ 9 behalf ( t me?od ( build+1 :i* proves x to be correct4 ,contr>iwise1 an analysis ( ! fly+ movem5t w %[ t x is ! "o feature :i* has militat$ aga9/ safety1 & t ma*9es w nev] be safe s long z ! angle ( ! body mu/ be dep5d$ ^u to control ! angle ( fly+4 ,fig4 #aa;a ,monoplane 9 ,flight4 ,9 ,fig4 #aa;a ?ree positions ( a monoplane are %[n1 ea* 9 horizontal flight4 ,let u say t ! fir/ figure ,a is go+ at #dj miles p] h\r1 ! second1 ,b1 at #ej1 & ! ?ird1 ,c1 at #fj miles4 ,! body 9 ,a is ne>ly horizontal1 ! angle ( ! plane ,d be+ su* t1 ) ! tail ,e also horizontal1 an ev5 flight is ma9ta9$4 ,:5 ! spe$ increases to #ej miles an h\r1 ! angle ( incid5ce 9 ! plane ,d mu/ be decreas$1 s t ! re> end ( ! frame mu/ be rais$1 :i* is done by giv+ ! tail an angle ( incid5ce1 o!rwise1 z ! upp] side ( ! tail %\ld meet ! air x w\ld drive ! re> end ( ! frame d[n1 & ?us defeat ! attempt to elevate t "p4 ,fig4 #ab4 ,angles ( ,flight4 ,z ! spe$ increases t5 miles m1 ! tail is swung d[n /ill fur!r & ! re> end ( ! frame is n[ actually above ! plane ( flight4 ,9 ord]1 n[1 to *ange ! angle ( flight1 )\t alt]+ ! spe$ ( ! ma*9e1 ! tail is us$ to effect ! control4 ,exam9e ! fir/ diagram 9 ,fig4 #ab4 ,?is %[s ! tail ,e /ill fur!r depress$1 & ! air /rik+ its l[] side1 causes an upw>d movem5t ( ! frame at t end1 :i* s mu* decreases ! angle ( incid5ce t ! a]oplane d>ts d[nw>dly4 ,9 ord] to asc5d1 ! tail1 z %[n 9 ! second diagram1 is elevat$ s z to depress ! re> end1 & n[ ! su/a9+ surface %oots upw>dly4 ,suppose t 9 ei!r ( ! positions #a or #b1 ?us describ$1 ! aviator %\ld lose control ( ! me*anism1 or x %\ld become d]ang$ or /ick1 conditions :i* h exi/$ 9 ! hi/ory ( ! art1 :at is !re to prev5t an accid5t8 ,9 ! fir/ case1 if !re is room1 ! ma*9e w loop ! loop1 & 9 ! second case ! ma*9e w move upw>dly until x is v]tical1 & !n1 9 all probability1 z its propell+ p[] is n suffici5t to hold x 9 t position1 l a helicopt]1 & hav+ absolutely no w+ support+ surface :5 9 t position1 x w d>t d[n tail =emo/4 ,a ,,non-,,*ang+ ,,body4--,we may contra/ ! =ego+ in/ances ( flight ) a ma*9e hav+ ! su/a9+ planes h+$ to ! body 9 su* a mann] z to make ! disposition ( its angles syn*ron\s ) ! tail4 ,9 o!r words1 see h[ a ma*9e acts t has ! angle ( flight controllable by bo? planes1--t is1 ! su/a9+ planes1 z well z ! tail4 ,fig4 #ac4 ,planes on ,non-*ang+ ,body4 ,9 ,fig4 #ac let ! body ( ! a]oplane be horizontal1 & ! su/a9+ planes ,b dispos$ at ! same angle1 :i* we w assume to be #ae degrees1 ?is be+ ! imag9>y angle = illu/rative purposes1 ) ! p[] ( ! ma*9e to drive x along horizontally1 z %[n 9 position #a4 ,9 position #b ! angles ( bo? planes are n[ at #aj degrees1 & ! spe$ #fj miles an h\r1 :i* /ill drives ! ma*9e =w>d horizontally4 ,9 position #c ! angle is /ill less1 be+ n[ only #e degrees b ! spe$ is increas$ to #hj miles p] h\r1 b 9 ea* in/ance ! body ( ! ma*9e is horizontal4 ,n[ x is obvi\s t 9 ord] to asc5d1 9 ei!r case1 ! *ang+ ( ! planes to a great] angle w\ld raise ! ma*9e1 b at ! same "t keep ! body on an ev5 keel4 ,fig4 #ad4 ,desc5t ) ,non-*ang+ ,body4 ,,desc5d+ ,,positions ,,by ,,p[] ,,control4--,9 ,fig4 #ad ! planes are ! same angles 9 ! ?ree positions respectively1 z 9 ,fig4 #ac1 b n[ ! p[] has be5 r$uc$1 & ! spe$s are #cj1 #be1 & #bj miles p] h\r1 9 positions ,a1 ,b & ,c4 ,suppose t 9 ei!r position ! p[] %\ld cease1 & ! control brok51 s t x w\ld be impossible to move ! planes4 ,:5 ! ma*9e beg9s to lose its mom5tum x w desc5d on a curve %[n1 = in/ance1 9 ,fig4 #ae1 :]e position #a ( ,fig4 #ad is tak5 z ! spe$ & angles ( ! plane :5 ! p[] ceas$4 ,fig4 #ae4 ,utiliz+ ,mom5tum4 ,,cutt+ ,,(f ,,! ,,p[]4--,?is curve1 ,a1 may rea* t po9t :]e mom5tum has ceas$ z a =w>dly-propell+ factor1 & ! ma*9e n[ beg9s to travel re>w>dly4 7,fig4 #af47 ,x has /ill ! entire support+ surfaces ( ! planes4 ,x _c loop-!-loop1 z 9 ! in/ance :]e ! planes are fix$ immovably to ! body4 ,c>efully /udy ! =ego+ arrangem5t1 & x w be se5 t x is m ne>ly 9 accord ) ! true fly+ pr9ciple z giv5 by nature ?an ! vaunt$ !ories & practices n[ indulg$ 9 & s p]si/5tly adh]$ to4 ,! body ( a fly+ ma*9e %\ld n be oscillat$ l a lev]4 ,! support ( ! a]oplane %\ld nev] be tak5 f x4 ,:ile x may be impossible to prev5t a ma*9e f com+ d[n1 x c be prev5t$ f ov]turn+1 & ?is c be done )\t 9 ! lea/ detract+ f x /ructurally4 ,fig4 #af4 ,rev]s+ ,motion4 ,! plan sugge/$ has "o great fault1 h[ev]4 ,x w be impossible ) su* a /ructure to cause x to fly upside d[n4 ,x does n pres5t any means :]eby d>e-devil /unts c be p]=m$ to edify ! gr&/&4 ,9 ?is respect x is n 9 ! same class ) ! pres5t types4 ,,! ,,/>t+ ,,movem5t4--,exam9e ?is plan f ! position ( />t+1 & see ! advantages x possesses4 ,9 ^! illu/rations we h us$1 = conv5i5ce only1 ! monoplane type1 & x is obvi\s t ! same rem>ks apply to ! bi-plane4 ,fig4 #ag %[s ! />t+ position ( ! /ock monoplane1 9 position #a1 :ile x is be+ initially run ov] ! gr\nd1 prep>atory to laun*+4 ,position #b repres5ts ! negative angle at :i* ! tail is ?r[n1 :i* movem5t depresses ! re> end ( ! frame & ?us gives ! support+ planes ! prop] angle to raise ! ma*9e1 ?r\gh a positive angle ( incid5ce1 ( ! plane4 ,fig4 #ag4 ,%[+ *ang+ angle ( body4 ,,! ,,sugge/$ ,,type4--,9 ,fig4 #ah ! sugge/$ type is %[n ) ! body normally 9 a horizontal position1 & ! planes 9 a neutral position1 z repres5t$ 9 position #a4 ,:5 suffici5t spe$ _h be5 atta9$ bo? planes are turn$ to ! same angle1 z 9 position #b1 & flight is initiat$ )\t ! abnormal oscillat+ motion ( ! body4 ,b n[ let u see :at takes place ! mom5t ! pres5t type is laun*$4 ,if1 by any error on ! "p ( ! aviator1 he %\ld fail to readju/ ! tail to a neutral or to a prop] angle ( incid5ce1 aft] leav+ ! gr\nd1 ! ma*9e w\ld try to p]=m an ov]-head loop4 ,! sugge/$ plan does n require ?is caution4 ,! ma*9e may rise too rapidly1 or its planes may be at too great an angle = ! p[] or ! spe$1 or ! planes may be at too small an angle1 b 9 ei!r case1 neglect w\ld n turn ! ma*9e to a dang]\s position4 ,^! sugge/ions are (f]$ to ! novice1 because !y g to ! v f\ndation ( a correct und]/&+ ( ! pr9ciples involv$ 9 ! build+ & 9 ! manipulation ( fly+ ma*9es & :ile !y are c\nt] to ! beliefs ( aviators1 z is %[n by ! p]si/5cy 9 adh]+ to ! old me?ods1 are believ$ to be me*anically correct1 & wor?y ( consid]ation4 ,,! ,,l[ ,,c5t] ,,( ,,gravity4--,b we h /ill to exam9e ano!r feature :i* %[s ! wrong pr9ciple 9 ! fix$ planes4 ,! "q is (t5 ask$1 :y d ! build]s ( a]oplanes place mo/ ( ! weight up close to ! planes8 ,x mu/ be obvi\s to ! novice t ! l[] ! weight ! less liability ( ov]turn+4 ,,=e ,,& ,,aft ,,oscillations4--,! answ] is1 t :5 ! weight is plac$ bel[ ! planes x acts l a p5dulum4 ,:5 ! ma*9e is travel+ =w>d1 & ! propell] ceases its motion1 z x usually does in/antane\sly1 ! weight1 be+ bel[1 & hav+ a c]ta9 mom5tum1 cont9ues to move on1 & ! plane surface meet+ ! resi/ance j ! same1 & hav+ no means to pu% x =w>d1 a great] angle ( resi/ance is =m$4 ,9 ,fig4 #ai ?is action ( ! two =ces is illu/rat$4 ,! plane at ! spe$ ( #cj miles is at an angle ( #ae degrees1 ! body ,b ( ! ma*9e be+ horizontal1 & ! weight ,c susp5d$ directly bel[ ! support+ surfaces4 ,! mom5t ! p[] ceases ! weight cont9ues mov+ =w>dly1 & x sw+s ! =w>d end ( ! frame upw>dly1 ,fig4 #bj1 & we n[ h1 z 9 ! second figure1 a new angle ( incid5ce1 :i* is #cj degrees1 in/ead ( #ab4 ,x w be und]/ood t 9 ord] to effect a *ange 9 ! position ( ! ma*9e1 ! =w>d end asc5ds1 z %[n by ! dott$ l9e ,a4 ,fig4 #bj4 ,action :5 ,propell] ceases to pull4 ,! weight a hav+ n[ asc5d$ z f> z possible =w>d 9 its sw+1 & its motion *eck$ by ! bank+ action ( ! plan x w aga9 sw+ back1 & aga9 c>ry ) x ! frame1 ?us sett+ up an oscillation1 :i* is extremely dang]\s4 ,! tail ,e1 ) its un*ang$ angle1 does n1 9 any degree1 aid 9 ma9ta9+ ! frame on an ev5 keel4 ,be+ ne>ly horizontal :ile 9 flight1 if n at a negative angle1 x actually assi/s ! =w>d end ( ! frame to asc5d4 ,,application ,,( ,,! ,,new ,,pr9ciple4--,ext5d+ ! application ( ! sugge/$ =m1 let u see :]e9 x w prev5t ?is p5dul\s motion at ! mom5t ! p[] ceases to ex]t a =w>dly- propell+ =ce4 ,fig4 #ba4 ,syn*ron\sly mov+ ,planes4 ,9 ,fig4 #ba ! body ,a is %[n to be equipp$ ) ! support+ plane ,b & ! tail a1 s !y are adju/able simultane\sly at ! same angle1 & ! weight ,d is plac$ bel[1 simil> to ! o!r /ructure4 ,at e mom5t dur+ ! =w>d movem5t ( ?is type ( /ructure1 ! re> end ( ! ma*9e has a t5d5cy to move upw>dly1 ! same z ! =w>d end1 h5ce1 :5 ! weight seeks1 9 ?is case to g on1 x acts on ! re> plane1 or tail1 & causes t end to raise1 & ?us by mutual action1 prev5ts any p5dul\s sw+4 ,,l[ ,,weight ,,n ,,necess>y ,,) ,,syn*ron\sly-,,mov+ ,,w+s4 --,a little reflection w conv9ce any "o t if ! two w+s move 9 h>mony1 ! weight does n h to be plac$ l[1 & ?us /ill fur!r aid 9 mak+ a compact ma*9e4 ,by increas+ ! area ( ! tail1 & mak+ t a true support+ surface1 in/ead ( a m]e idl]1 ! weight c be mov$ fur!r back1 ! di/ance transv]sely across ! planes may be %ort5$1 & 9 t way /ill fur!r increase ! lat]al /ability4 ,,*apt] ,v ,,diff]5t ,,ma*9e ,,types ,,& ,,_! ,,*>act]i/ics ,,!re are ?ree di/9ct types ( heavi]-?an- air ma*9es1 :i* are widely sep>at$ 9 all _! *>act]i/ics1 s t !re is sc>cely a s+le feature 9 common4 ,two ( !m1 ! a]oplane1 & ! or?opt]1 h prototypes 9 nature1 & are di/+ui%$ by _! respective simil>ities to ! so>+ birds1 & ^? ) flapp+ w+s4 ,! ,helicopt]1 on ! o!r h&1 has no antec$5t type1 b is dep5d5t = its rais+ p[]s on ! pull ( a propell]1 or a plurality ( !m1 con/ruct$1 z w be po9t$ out h]e9aft]4 ,,a]oplanes4--,! only =m :i* has met ) any success is ! a]oplane1 :i*1 9 practice1 is made 9 two di/9ct =ms1 "o ) a s+le set ( support+ planes1 9 imitation ( birds1 & call$ a monoplane2 & ! o!r hav+ two w+s1 "o above ! o!r1 & call$ ! bi-plane1 or two-planes4 ,all ma*9es n[ on ! m>ket :i* d n dep5d on w+ oscillations come "u ^? types4 ,,! ,,monoplane4--,! s+le plane type has "s /rong claims = support4 ,fir/ ( ^! is ! comp>atively small head resi/ance1 due to ! entire abs5ce ( v]tical support+ po/s1 :i* latt] are necess>y ) ! biplane type4 ,! brac+ supports :i* hold ! out] ends ( ! planes are compos$ ( wires1 :i* (f] b little resi/ance1 comp>atively1 9 flight4 ,,its ,,advantages4--,!n ! v]tical height ( ! ma*9e is mu* less ?an 9 ! biplane4 ,z a result ! weight1 :i* is f>!r bel[ ! support+ surface ?an 9 ! biplane1 aids 9 ma9ta9+ ! lat]al /ability1 p>ticul>ly s9ce ! support+ frame is high]4 ,usually1 = ! same w+ spread1 ! monoplane is n>r[]1 lat]ally1 :i* is a fur!r aid to prev5t tilt+4 ,,its ,,disadvantages4--,b x also has disadvantages :i* mu/ be app>5t f its /ructure4 ,z all ! support+ surface is conc5trat$ 9 half ! numb] ( planes1 !y mu/ be made ( great] wid? =e & aft1 & ?is1 z we %all see1 lat] on1 proves to be a disadvantage4 ,x is also d\bt$ :e!r ! monoplane c be made z /rong /ructurally z ! o!r =m1 ow+ to ! lack ( ! truss =mation :i* is ! /rong po9t ) ! sup]pos$ frame4 ,a truss is a =m ( con/ruction :]e braces c be us$ f "o memb] to ! next1 s z to brace & /iff5 ! :ole4 ,,! ,,biplane4--,nature does n furni% a type ( creature :i* has sup]pos$ w+s4 ,9 ?is p>ticul> ! inv5tor surely did n foll[ nature4 ,! reasons :i* l$ man to employ ?is type may be summ>iz$ z foll[s3 ,9 exp]im5t+ ) planes x is f\nd t a broad =e & aft surface w n lift z mu* z a n>r[ plane4 ,?is subject is fully expla9$ 9 ! *apt] on ,! ,lift+ ,surfaces ( ,planes4 ,9 view ( t ! te*nical descriptions ( ! op]ation w n be t\*$ ^u at ?is place1 except s f> z x may be necess>y to set =? ! pres5t subject4 ,?is peculi>ity is due to ! accumulation ( a mass ( mov+ air at ! re> end ( ! plane1 :i* detracts f its lift+ p[]4 ,z x w\ld be a po9t ( /ructural weakness to make ! w+s n>r[ & v long1 ,w5ham _m ye>s ago sugge/$ ! idea ( plac+ "o plane above ! o!r1 & lat] on ,*anute1 an eng9e]1 us$ t =m almo/ exclusively1 9 exp]im5t+ ) 8 glid]s4 ,x 0 due to 8 influ5ce t ! ,wrights adopt$ t =m 9 _! glid+ exp]im5ts1 & lat] on con/ruct$ _! successful fly]s 9 t mann]4 ,orig9ally ! monoplane 0 ! type g5]ally employ$ by exp]im5t]s1 su* z ,lili5?al1 & o!rs4 ,,/ability ,,9 ,,biplanes4--,biplanes are n naturally z /able lat]ally z ! monoplane4 ,! reason is1 t a d[nw>d tilt has ! b5efit ( only a n>r[ surface1 comp>able ) ! monoplane1 :i* has broadness ( w+4 ,to illu/rate ?is1 let u assume t we h a biplane ) planes five feet f front to re>1 & ?irty-six feet 9 l5g?4 ,?is w\ld give two planes ) a su/a9+ surface ( #cfj squ>e feet4 ,! monoplane w\ld1 probably1 divide ?is area into "o plane eight & a half feet f front to re>1 & #db feet 9 l5g?4 ,9 ! monoplane ea* w+ w\ld project out ab\t ?ree feet m on ea* side1 b x w\ld h eight & a half feet =e & aft spread to ! biplane's five feet1 & ?us act z a great] support4 ,,! ,,or?opt]4--,! t]m or?opt]1 or orni?opt]1 mean+ bird w+1 is appli$ to su* fly+ ma*9es z dep5d on w+ motion to support !m 9 ! air4 ,unque/ionably1 a support c be obta9$ by beat+ on ! air b to d s x is necess>y to adopt ! pr9ciple employ$ by nature to secure an upw>d propulsion4 ,z po9t$ out else:]e1 x _c be ! concav$ type ( w+1 or its %ape1 or relative size to ! weight x mu/ c>ry4 ,z nature has furni%$ su* a v>iety ( data on ^! po9ts1 all v>y+ to su* a rem>kable degree1 we mu/ look else:]e to f9d ! secret4 ,only "o o!r direction (f]s any opportunity1 & t is 9 ! individual w+ movem5t4 ,,nature',s ,,type ,,n ,,uni=m4--,:5 ?is is exam9$1 ! same obscurity surr\nds ! issue4 ,ev5 ! spe$s v>y to su* an ext5t t :5 x is tri$ to diff]5tiate !m1 9 comp>ison ) =m1 %ape1 & con/ruction1 ! exp]im5t] f9ds himself wrapt 9 d\bt & p]plexity4 ,b birds d fly1 not)/&+ ?is wond]ful array ( contradictory exhibitions4 ,obs]vation has n enabl$ u to le>n :y ^! ?+s are s4 ,high au?orities1 & m5 :o are exp]t aviators1 tell u t ! bird flies because x is able to pick out asc5d+ air curr5ts4 ,,!ories ,,ab\t ,,flight ,,( ,,birds4--,!n we are (f]$ ! !ory t ! bird has an in/9ct :i* tells x j h[ to balance 9 ! air :5 its w+s are once set 9 motion4 ,frequ5tly1 :at is tak5 = in/9ct1 is some?+ entirely diff]5t4 ,x has be5 assum$1 = in/ance1 t a cycli/ mak+ a turn at a rapid spe$1 & a bird fly+ ar\nd a circle w ?r[ ! upp] "p ( ! body inw>dly to c\nt]act ! c5trifugal =ce :i* t5ds to ?r[ x outw>dly4 ,exp]im5ts ) ! monorail c>1 :i* is equipp$ ) a gyroscope to hold x 9 a v]tical position1 %[ t :5 ! c> approa*es a curve ! c> w lean inw>dly1 exactly ! same z a bird1 or a cycli/1 & :5 a /raight /ret* is rea*$1 x w aga9 /raight5 up4 ,,in/9ct4--,n[1 ei!r ! c>1 s equipp$ possesses in/9ct1 or !re mu/ be a pr9ciple 9 ! laws ( nature :i* produces ! simil>ity ( action4 ,9 l mann] !re mu/ be "s pr9ciple t is entirely indep5d5t ( ! =m ( matt]1 or its arrangem5t1 :i* enables ! bird to p]=m its evolutions4 ,we are l$ to believe f all ! =ego+ consid]ations t x is ! mann] or ! =m ( ! motion4 ,,mode ,,( ,,motion4--,9 ?is respect x seems to be comp>able 9 e respect to ! great & univ]sal law ( ! motions 9 ! univ]se4 ,?us1 light1 heat & electricity are ! same1 ! manife/ations be+ unlike only because !y h diff]5t modes ( motion4 ,ev]y?+ 9 nature manife/s itself by motion4 ,x is ! only way 9 :i* nature acts4 ,e trans=mation f "o ?+ to ano!r1 is by way ( a movem5t :i* is *>act]i/ic 9 itself4 ,:y1 !n1 %\ld ?is great my/]y ( nature1 act unlike ! o!r portions ( :i* x is a "p8 ,,! ,,w+ ,,/ructure4--,! w+ /ructure ( e fly+ creature t man has exam9$1 has "o univ]sal po9t ( simil>ity1 & t is ! mann] ( its connection ) ! body4 ,x is a sort ( univ]sal jo9t1 :i* p]mits ! w+ to sw+ up & d[n1 p]=m a gyratory movem5t :ile do+ s1 & folds to ! re> :5 at re/4 ,"s h ^! movem5ts 9 a great] or less degree1 or capable ( a great] range2 b ! jo9t is ! same1 ) sc>cely an exception4 ,:5 ! /roke ( ! w+ is d[nw>dly ! re> m>g9 is high] ?an ! front edge1 s t ! d[nw>d beat n only raises ! body upw>dly1 b also propels x =w>dly4 ,,! ,,w+ ,,movem5t4--,! mom5t ! w+ />ts to sw+ upw>dly ! re> end is depress$1 & n[1 z ! bird is mov+ =w>dly1 ! w+ surface has a positive angle ( incid5ce1 & z ! w+ rises :ile ! =w>d motion is tak+ place1 !re is no resi/ance :i* is effective en\gh to c\nt]act ! mom5tum :i* has be5 set up4 ,! great problem is to put ?is motion into a me*anical =m4 ,! tr\ble is n ascribable to ! inability ( ! me*anic to describe ?is movem5t4 ,x is an exce$+ly simple "o4 ,! fir/ difficulty is 9 ! mat]ial t mu/ be us$4 ,lightness & /r5g? = ! w+ itself are ! fir/ requirem5ts4 ,!n rigidity 9 ! jo9t & 9 ! ma9 rib ( ! w+1 are ! next consid]ations4 ,9 ^! respects ! ability ( man is limit$4 ,! w+ ligatures ( fly+ creatures is exce$+ly /rong1 & flexible2 ! holl[ bone =mation & ! fea!rs are extremely light1 comp>$ ) _! su/a9+ p[]s4 ,,! ,,helicopt] ,,motion4--,! helicopt]1 or helix-w+1 is a =m ( fly+ ma*9e :i* dep5ds on revolv+ screws to ma9ta9 x 9 ! air4 ,_m propell]s are n[ made1 six feet 9 l5g?1 :i* h a pull ( f #djj to #ejj p\nds4 ,if ^! are plac$ on v]tically-dispos$ %afts !y w\ld ex]t a l p[] to raise a ma*9e f ! e>?4 ,obvi\sly1 x is difficult to equip su* a ma*9e ) planes = su/a9+ x 9 flight1 aft] x is once 9 ! air1 & unless su* means are provid$ ! propell]s !mselves mu/ be ! me*anism to propel x horizontally4 ,?is means a *ange ( direction ( ! %afts :i* support ! propell]s1 & ! con/ruction is necess>ily m complicat$ ?an if !y 7 held )9 non-*angeable be>+s4 ,?is pr9ciple1 h[ev]1 af=ds a saf] means ( navigat+ ?an ! or?opt] type1 because ! blades ( su* an in/rum5t c be =c$ ?r\gh ! air ) inf9itely great] spe$ ?an beat+ w+s1 & x devolves on ! inv5tor to devise "s =m ( app>atus :i* w p]mit ! *ange ( pull f a v]tical to a horizontal direction :ile 9 flight4 ,,*apt] ,,vi ,,! ,,lift+ ,,surfaces ,,( ,,a]oplanes ,,?is subject includes ! =m1 %ape & angle ( planes1 us$ 9 flight4 ,x is ! direction 9 :i* mo/ ( ! en]gy has be5 exp5d$ 9 develop+ ma*9es1 & ! true =m is /ill involv$ 9 d\bt & unc]ta9ty4 ,,relative ,,spe$ ,,& ,,angle4--,! relative spe$ & angle1 & ! camb]1 or ! curv$ =mation ( ! plane1 h be5 consid]$ 9 all _! aspects1 s t ! art 9 ?is respect has advanc$ ) rapid /rides4 ,,n>r[ ,,plates ,,mo/ ,,effective4--,x 0 le>n$1 9 ! e>ly /ages ( ! developm5t by practical exp]im5ts1 t a n>r[ plane1 =e & aft1 produces a great] lift ?an a wide "o1 s t1 assum+ ! plane has #ajj squ>e feet ( su/a9+ surface1 x is f> bett] to make ! %ape five feet by tw5ty ?an t5 by t54 ,h[ev]1 x mu/ be obs]v$1 t to use ! n>r[ blade effectively1 x mu/ be project$ ?r\gh ! air ) ! long m>g9 =w>dly4 ,its su/a9+ p[] p] squ>e foot ( surface is mu* less if =c$ ?r\gh ! air l5g?wise4 ,exp]im5ts h %[n :y a n>r[ blade has proportionally a great] lift1 & ?is may be m cle>ly und]/ood by exam9+ ! illu/rations :i* %[ ! movem5t ( planes ?r\gh ! air at appropriate angles4 ,fig4 #bb4 ,/ream l9es along a plane4 ,,/ream ,,l9es ,,along ,a ,,plane4--,9 ,fig4 #bb1 ,a is a flat plane1 :i* we w assume is #aj feet f ! front to ! re> m>g94 ,= conv5i5ce sev5 /ream l9es ( air are %[n1 :i* contact ) ?is incl9$ surface4 ,! fir/ l9e #a1 aft] ! contact at ! =w>d end1 is driv5 d[nw>dly along ! surface1 s t x =ms :at we might t]m a mov+ film4 ,! second air /ream #b1 /rikes ! fir/ /ream1 foll[$ successively by ! o!r /reams1 #c1 #d1 & s on1 ea* succe$+ /ream be+ compell$ to ride ov]1 or along on ! prec$+ mass ( cu%ion$ air1 ! la/ l9es1 ne> ! l[] end1 be+1 !re=e1 at su* angles1 & contact+ ) su* a rapidly-mov+ column1 t x produces b little lift 9 comp>ison ) ! #a/1 #b;d & #c;d /ream l9es4 ,^! /ream l9es are tak5 by imag9+ t ! air approa*es & contacts ) ! plane only along ! l9es indicat$ 9 ! sket*1 al?\gh !y also 9 practice are active aga9/ e "p ( ! plane4 ,,! ,,c5t] ,,( ,,pressure4--,9 su* a plane ! c5t] ( pressure is ne> its upp] end1 probably ne> ! l9e #c1 s t ! great] portion ( ! lift is ex]t$ by t "p ( ! plane above l9e #c4 ,,air ,,l9es ,,on ,,! ,,upp] ,,side ,,( ,,! ,,plane4-- ,n[1 ano!r factor mu/ be consid]$1 namely1 ! effect produc$ on ! upp] side ( ! plane1 ov] :i* a r>efi$ area is =m$ at c]ta9 po9ts1 &1 9 practice1 ?is also produces1 or %\ld be utiliz$ to effect a lift4 ,,r>efi$ ,,area4--,:at is call$ a r>efi$ area1 has ref]5ce to a /ate or condition ( ! atmosph]e :i* has less ?an ! normal pressure or quantity ( air4 ,?us1 ! pressure at sea level1 is ab\t #ad #c_/d p] squ>e in* ,z we asc5d ! pressure gr[s less1 & ! air is ?us r>]1 or1 !re is less ( x4 ,?is is a condition :i* is normally f\nd 9 ! atmosph]e4 ,sev]al ?+s t5d to make a r>efi$ condition4 ,"o is altitude1 to :i* we h j ref]r$4 ,!n heat w exp& air1 mak+ x less d5se1 or light]1 s t x w move upw>dly1 to be replac$ by a cold] body ( air4 ,9 a]onautics nei!r ( ^! conditions is ( any importance 9 consid]+ ! lift+ p[] ( a]oplane surfaces4 ,,r>efaction ,,produc$ ,,by ,,motion4--,! ?ird r>efi$ condition is produc$ by motion1 & g5]ally ! area is v limit$ :5 br\ght ab\t by ?is means4 ,if1 = in/ance1 a plane is held horizontally & all[$ to fall t[>d ! e>?1 x w be ret>d$ by two =ces1 namely1 compression & r>efaction1 ! =m] act+ on ! "u side ( ! plane1 & ! latt] on ! upp] side4 ,( ! two r>efaction is ! mo/ effectual1 & produces a great] effect ?an compression4 ,?is may be prov5 by compress+ air 9 a long pipe1 & not+ ! diff]5ce 9 gauge pressure betwe5 ! ends1 & !n us+ a suction pump on ! same pipe4 ,:5 a plane is =c$ ?r\gh ! air at any angle1 a r>efi$ area is =m$ on ! side :i* is opposite ! "o hav+ ! positive angle ( incid5ce4 ,if ! plane c be s =m$ z to make a l>ge & effective area x w add greatly to ! value ( ! su/a9+ surface4 ,un=tunately1 ! long fiat plane does n l5d any aid 9 ?is p>ticul>1 z ! /ream l9e fl[s d[n along ! top1 z %[n 9 ,fig4 #bc1 )\t be+ ( any s]vice4 ,fig4 #bc4 ,air l9es on ! upp] side ( a ,plane4 ,,! ,,concav$ ,,plane4--,^! consid]ations l$ to ! adoption ( ! concav$ plane =mation1 & = purposes ( comp>ison ! diagram1 ,fig4 #bd1 %[s ! plane ,b ( ! same l5g? & angle z ! /raight planes4 ,9 exam9+ ! successive /ream l9es x w be f\nd t :ile ! #a/1 #b;d & #c;d l9es h a little less angle ( impact ?an ! correspond+ l9es 9 ! /raight plane1 ! la/ l9es1 #e1 #f & #g1 h mu* great] angles1 s t only l9e #d /rikes ! plane at ! same angle4 ,su* a plane /ructure w\ld1 !re=e1 h its c5t] ( pressure some:]e betwe5 ! l9es #c & #d1 & ! lift be+ ?us1 practically1 uni=m ov] ! surface1 w\ld be m effective4 ,,! ,,c5t] ,,( ,,pressure4--,?is is a t]m us$ to indicate ! place on ! plane :]e ! air acts ) ! greate/ =ce4 ,x has ref]5ce to a po9t betwe5 ! front & re> m>g9s only ( ! plane4 ,fig4 #bd4 ,air l9es bel[ a concav$ ,plane4 ,,utiliz+ ,,! ,,r>efi$ ,,area4--,?is /ructure1 h[ev]1 has ano!r important advantage1 z x utilizes ! r>efi$ area :i* is produc$1 & :i* may be und]/ood by ref]5ce to ,fig4 #be4 ,! plane ,b1 ) its upw>d curve1 & at ! same angle z ! /raight plane1 has its l[] end s curv$1 ) relation to ! =w>d movem5t1 t ! air1 9 ru%+ pa/ ! upp] end1 _c foll[ ! curve rapidly en\gh to ma9ta9 ! same d5sity along ,c1 h5ce ?is ex]ts an upw>d pull1 due to ! r>efi$ area1 :i* s]ves z a lift+ =ce1 z well z ! compress$ mass b5ea? ! plane4 ,,*ang+ ,,c5t] ,,( ,,pressure4--,! c5t] ( pressure is n con/ant4 ,x *anges ) ! angle ( ! plane1 b ! range is consid]ably less on a concave surface ?an on a flat plane4 ,fig4 #be4 ,air l9es above a convex ,plane4 ,9 a plane dispos$ at a small angle1 ,a1 z 9 ,fig4 #bf1 ! c5t] ( pressure is ne>] ! =w>d end ( ! plane ?an ) a great] positive angle ( incid5ce1 z 9 ,fig4 #bg1 & :5 ! plane is 9 a normal fly+ angle1 x is at ! c5t]1 or at a po9t midway betwe5 ! m>g9s4 ,,plane ,,mon/rosities4--,gr[+ out ( ! idea t ! w+ 9 nature mu/ be fai?fully copi$1 x is believ$ by _m t a plane ) a pron\nc$ ?ickness at its =w>d m>g9 is "o ( ! secrets ( bird flight4 ,accord+ly c]ta9 inv5tors h design$ types ( w+s :i* are %[n 9 ,figs4 #bh & #bi4 ,fig4 #bh ,*ang+ c5t]s ( ,pressures4 ,fig #bi4 ,bird-w+ /ructures4 ,bo? ( ^! types h pron\nc$ bulges1 design$ to split ! air1 =gett+1 app>5tly1 t 9 o!r p>ts ( ! ma*9e e ef=t is made to prev5t head resi/ance4 ,,! ,,bird ,,w+ ,,/ructure4--,! advocates ( su* con/ruction ma9ta9 t ! =w>d edge ( ! plane mu/ =cibly drive ! air column ap>t1 because ! bird w+ is s made1 & t :ile x may n appe> exactly logical1 /ill !re is some?+ ab\t x :i* seems to d ! "w1 & = t reason x is l>gely adopt$4 ,,:y ,,! ,,bird',s ,,w+ ,,has ,a ,,pron\nc$ ,,bulge4--,let u exam9e ?is claim4 ,! bone :i* supports ! entire w+ surface1 call$ ! 7pectoral71 has a heavy duty to p]=m4 ,x is s con/ruct$ t x mu/ )/& an extraord9>y torsional /ra91 be+ locat$ at ! =w>d portion ( ! w+ surface4 ,torsion has ref]5ce to a twi/+ motion4 ,9 "s cases1 z 9 ! bat1 ?is prim>y bone has an atta*m5t to ! re> ( ! ma9 jo9t1 :]e ! re> m>g9 ( ! w+ is atta*$ to ! leg ( ! animal1 ?us giv+ x a support & ! ma9 bone is1 !re=e1 reliev$ ( ?is torsional /ress4 ,,! ,,bat',s ,,w+4--,an exam9ation ( ! bat's w+ %[s t ! pectoral bone is v small & ?91 ?us prov+ t :5 ! entire w+ support is ?r[n ^u ! prim>y bone x mu/ be l>ge en\gh to enable x to c>ry out its functions4 ,x is c]ta9ly n s made because x is a necess>y %ape :i* be/ adapts x = fly+4 ,if su* 7 ! case !n nature err$ 9 ! case ( ! bat1 & x made a mi/ake 9 ! h\sefly's w+ :i* has no su* ant]ior enl>gem5t to assi/ 787 x 9 fly+4 ,,an ,,abnormal ,,%ape4--,ano!r illu/ration is %[n 9 ,fig4 #cj1 :i* has a deep concave directly beh9d ! =w>d m>g91 z at ,a1 s t :5 ! plane is at an angle ( ab\t #bb degrees1 a horizontal l9e1 z ,b1 pass+ back f ! nose1 t\*es ! incurv$ surface ( ! plane at a po9t ab\t "o-?ird ( its measurem5t back across ! plane4 ,fig4 #cj4 ,"o ( ! ,mon/rosities ,?is =m is an exact copy ( ! w+ ( an actual bird1 b x belongs1 n to ! so>+1 b to ! class :i* dep5ds on flapp+ w+s1 & z su* x _c be und]/ood :y x %\ld be us$ = so>+ ma*9es1 z all a]oplanes are4 ,! =ego+ in/ances ( con/ruction are cit$ to %[ h[ wildly ! imag9ation w roam :5 x foll[s wrong ideals4 ,,! ,,tail ,,z ,a ,,monitor4--,! t5d5cy ( ! c5t] ( pressure to *ange necessitates a correctional means1 :i* is suppli$ 9 ! tail ( ! ma*9e1 j z ! tail ( a kite s]ves to hold x at a correct angle ) respect to ! w9d & ! pull ( ! support+ /r+4 ,,*apt] ,,vii ,,abnormal ,,fly+ ,,/unts ,,& ,,spe$s ,,pequod1 a ,fr5*man1 ye/]day repeat$ly p]=m$ ! rem>kable feat ( fly+ ) ! ma*9e upside d[n4 ,?is exhibition %[s t ! age ( p]fection has arriv$ 9 fly+ ma*9es1 & t /ability is an accompli%$ fact4--,news item4 ,?is is quot$ to %[ h[ little ! g5]al public kn[s ( ! subject ( aviation4 ,x correctly repres5ts ! a*ievem5t ( ! aviator1 & x probably voic$ ! s5tim5t ( _m sci5tific m51 z well z ( ! great majority ( aviators4 ,a few days aft]w>ds1 ! same newspap] publi%$ ! foll[+3 ,lieut5ant ----1 :ile exp]im5t+ ye/]day morn+1 met 8 dea? by ! ov]turn+ ( 8 ma*9e at an altitude ( #cjj met]s4 ,dea? 0 in/antane\s1 & ! ma*9e 0 completely de/roy$4 ,! ma*9es us$ by ! two m5 7 ( ! same manufacture1 z ,pequod us$ a /ock ma*9e :i* 0 /rongly brac$ to support ! inv]t$ weight1 b o!rwise x 0 n unlike ! well kn[n type ( monoplane4 ,bea*y has s9ce repeat$ ! exp]im5t ) a bi-plane1 & x is a feat :i* has _m imitators1 & :ile ^? rem>kable exhibitions are go+ on1 "o cata/rophe foll[s ! o!r ) ! same regul>ity z 9 ! pa/4 ,let u consid] ?is phase ( fly+4 ,are !y ( any value1 & :]e9 d !y tea* any?+ t may be utiliz$1 ,,lack ,,( ,,improvem5ts ,,9 ,,ma*9es4--,x is rem>kable t n "o s+le =w>d /ep has be5 tak5 to improve ! type ( fly+ ma*9es = ! pa/ five ye>s4 ,!y possess ! same %ape1 _! /abiliz+ qualities & me*anism = assur+ /ability are /ill ! same4 ,,m5 ,,exp$it$1 ,,& ,,n ,,! ,,ma*9e4--,! fact is1 t dur+ ?is p]iod ! man has be5 exploit$ & n ! ma*9e4 ,m5 h le>n$1 "s few ( !m1 to p]=m peculi> /unts1 su* z loop+ ! loop1 ! side glide1 ! drop1 & o!r features1 :i* look1 & are1 haz>d\s1 all ( :i* p&] to ! s5tim5ts ( ! spectators4 ,,abnormal ,,fly+ ,,( ,,no ,,value4--,x w\ld be too broad an ass]tion to say t x has absolutely no value1 because ev]y?+ has its use 9 a c]ta9 s5se1 b if we are to judge f ! progress ( inv5tions 9 o!r directions1 su* exhibitions w n improve ! art ( build+ ! device1 or make a fool-pro( ma*9e4 ,inde$1 x is ! v ?+ :i* s]ves z a det]r5t1 r ?an an inc5tive4 ,if ma*9es c be h&l$ 9 su* a rem>kable mann]1 !y mu/ be1 inde$1 p]fect6 ,no?+ m is ne$$6 ,!y mu/ repres5t ! highe/ /ructural type ( me*anism6 ,t is ! idea s\ght to be convey$ 9 ! fir/ p>agraph quot$4 ,x is p]nici\s1 in/ead ( praisewor?y1 because x gives a false impression1 & x is rem>kable t ev5 c]ta9 sci5tific j\rnals h gravely discuss$ ! p]fect$ 787 type ( fly+ ma*9e z demon/rat$ by ! exp]im5ts allud$ to4 ,,! ,,art ,,( ,,juggl+4--,we may1 occasionally1 see a cycli/ :o und]/&s ! art ( balanc+ s well t he c1 ) ease1 ride a ma*9e :i* has only a s+le :eel2 or he c1 ) a /ock bicycle1 ride x 9 e conceivable attitude1 & make x p]=m all sorts ( feats4 ,x m]ely %[s t man has become an exp]t at juggl+ ) a ma*9e1 ! same z he manipulates balls1 & :eels1 & o!r artifices1 by 8 dext]ity4 ,,practical ,,uses ,,! ,,be/ ,,te/4--,! bicycle did n require su* displays to br+ x to p]fection4 ,x has be5 ! hi/ory ( e inv5tion t improvem5ts 7 br\ght ab\t1 n by abnormal exp]im5ts1 b by practical uses & by normal developm5ts4 ,! ability ( an aviator to fly ) ! ma*9e 9 an inv]t$ position is no te/ ( ! ma*9e's /ability1 nor does x 9 any mann] prove t x is correctly built4 ,x is simply & solely a juggl+ feat--some?+ 9 ! capacity ( a c]ta9 man to p]=m1 & attract att5tion because !y are out ( ! ord9>y4 ,,concav$ ,,& ,,coxvex ,,planes3--,!y 7 p]=m$ z exhibition features1 & int5d$ z su*1 & none ( ! expon5ts ( t k9d ( fly+ h ! effront]y to claim t !y prove any?+ ( value 9 ! ma*9e itself1 except t x incid5tally has de/roy$ ! l>gely vaunt$ claim t concav$ w+s = support+ surfaces are necess>y4 ,,h[ ,,mom5tum ,,is ,a ,,factor ,,9 ,,inv]t$ ,,fly+4-- ,:5 fly+ upside d[n1 ! convex side ( ! plane takes ! pressure ( ! air1 & ma9ta9s1 s x is ass]t$1 ! weight ( ! ma*9e4 ,?is is true dur+ t p]iod :5 ! loop is be+ made4 ,! evolution is made by fir/ d>t+ d[n1 z %[n 9 ,fig4 #ca1 f ! horizontal position1 #a1 to ! position #b1 :]e ! turn beg9s4 ,fig4 #ca4 ,fly+ upside d[n4 ,,turn+ ,,movem5t4--,n[ note ! *>act]i/ic angles ( ! tail1 :i* is ! controll+ factor4 ,9 position #a ! tail is practically horizontal4 ,9 fact1 9 all ma*9es1 at high flight1 ! tail is elevat$ s z to give little positive angle ( incid5ce to ! support+ planes4 ,9 position ,no4 #b1 ! tail is turn$ to an angle ( incid5ce to make ! d[nw>d plunge1 & :5 ! ma*9e has assum$ ! v]tical1 z 9 position #c1 ! tail is aga9 rev]s$ to assume ! angle1 z 9 #a1 :5 fly+ horizontally4 ,at ! l[] turn1 position #d1 ! tail is turn$ simil> to ! angle ( position #b1 :i* ?r[s ! re> end ( ! ma*9e d[n1 & z ! horizontal l9e ( flight is resum$1 9 an inv]t$ position1 z 9 position #d1 ! tail has ! same angle1 ) relation to ! frame1 z ! support+ planes4 ,dur+ ?is evolution ! eng9e is runn+1 & ! d[nw>d plunge develops a trem5d\s spe$1 & ! great mom5tum ?us acquir$1 toge!r ) ! pull+ p[] ( ! propell] :ile ?us 9 flight1 is suffici5t to propel x along horizontally1 :atev] ! plane surface curve1 or =mation may be4 ,x is ! mom5tum :i* su/a9s x 9 space1 n ! air pressure b5ea? ! w+s1 = reasons :i* we h h]et(ore expla9$4 ,flights ( suffici5t duration h ?us be5 made to prove t convex1 z well z concave surfaces are effici5t2 nev]!less1 9 its prop] place we h giv5 an exposition ( ! reason+ :i* l$ to ! adoption ( ! concav$ support+ surfaces4 ,,:5 ,,concav$ ,,planes ,,are ,,desirable4-- ,unque/ionably1 = sl[ spe$s ! concav$ w+ is desirable1 z w be expla9$1 b = high spe$s1 surface =mation has no value4 ,t is %[n by ,pequod's feat4 ,,! ,,spe$ ,,mania4--,?is is a type ( mania :i* p]vades e field ( activity 9 ! build+ ( a]oplanes4 ,spe$ conte/s are ( m importance to ! spectators on exhibition gr\nds ?an /ability or durability4 ,build]s p&] to ?is1 h5ce ma*9es are built on l9es :i* disreg>d e consid]ation ( safety :ile at normal flight4 ,,uses ,,( ,,fly+ ,,ma*9es4--,! ma*9e z n[ con/ruct$ is ( little use comm]cially4 ,)9 c]ta9 limitations x is valuable = sc\t+ purposes1 & attempts h be5 made to use x comm]cially4 ,b ! unreliable "* ( its p]=mances1 due to ! _m elem5ts :i* are necess>y to its prop] work+1 h op]at$ aga9/ x4 ,,p]fection ,,9 ,,ma*9es ,,mu/ ,,come ,,be=e ,,spe$4--,contr>y to e precept 9 ! build+ ( a new article1 ! attempt is made to make a ma*9e ) high spe$1 :i*1 9 ! v nature ( ?+s1 op]ates aga9/ its improvem5t4 ,! opposite lack ( spe$--is ( f> great] utility at ?is /age ( its developm5t4 ,,! ,,range ,,( ,,its ,,use4--,! subject might be illu/rat$ by assum+ t we h a l9e runn+ f ,a to ,z1 :i* indicates ! range ( spe$s 9 a]oplanes4 ,! limits ( spe$s are fairly /at$ z be+ )9 ?irty & eighty- five miles p] h\r4 ,less ?an ?irty miles are impossible ) any type ( plane1 & :ile "s h made high] spe$s ?an eighty-five miles x may be safe to assume t su* flights took place "u conditions :]e ! w9d contribut$ to ! movem5t4 ,fig4 #cb4 ,*>t %[+ ,range ( ,uses ,,comm]cial ,,utility4--,be=e ma*9es c be us$ successfully !y mu/ be able to atta9 sl[] spe$s4 ,alight+ is ! dang] factor4 ,spe$ ma*9es are dang]\s1 n 9 flight or at high spe$s1 b :5 attempt+ to l&4 ,a l>ge plane surface is incompatible ) spe$1 :i* is ano!r illu/ration t at high velocities support+ surfaces are n necess>y4 ,comm]cial uses require safety z ! fir/ elem5t1 & reliability z ! next ess5tial4 ,= pass5g] s]vice !re mu/ be an assurance t x w n ov]turn1 or t 9 l&+ dang] is n ev]-pres5t4 ,= ! c>ry+ ( freight int]rupt$ s]vice w militate aga9/ x4 ,h[ few are ! attempts to solve ! problem ( decreas$ spe$1 & :at an eag]1 re/less campaign is be+ wag$ to g fa/] & fa/]1 & ! addition ( e mile above ! record is hail$ z ano!r illu/ration ( ! p]fection 787 ( ! fly+ ma*9e4 ,to be able to navigate a ma*9e at t51 or fifte5 miles an h\r1 w\ld sc>cely be int]e/+ en\gh to m]it a p>agraph2 b su* an accompli%m5t w\ld be ( f> m value ?an all ( ,pequod's feats1 & be m f>-rea*+ 9 its effects ?an a flight ( two hundr$ miles p] h\r4 ,,*apt] ,,viii ,,kites ,,& ,,glid]s ,,kites are ( v anci5t orig91 & 9 ,*9a1 ,japan1 & ! ,malayan ,p59sula1 !y h be5 us$ = _m ye>s z toys1 & = ! purposes ( exhibit+ =ms ( m51 animals1 & p>ticul>ly dragons1 9 _! p]iodical displays4 ,,! ,,dragon ,,kite4--,! mo/ not$ ( all are ! dragon kites1 _m ( !m ov] a hundr$ feet 9 l5g?1 are adapt$ to sail along maje/ically1 _! s9u\s or snake-l motions l5d+ an idea ( reality to _! gorge\sly-color$ appe>ance 9 flight4 ,,its ,,con/ruction4--,x is v curi\sly wr\ght1 & z x mu/ be extremely light1 bamboo & rattan are almo/ :olly us$1 toge!r ) rice pap]1 9 its con/ruction4 ,fig4 #cc %[s "o =m ( ! arrangem5t1 9 :i* ! bamboo rib1 ,a1 9 :i* only two sections are %[n1 z ,b1 ,b1 =m ! backbone1 & ^! sections are secur$ toge!r ) pivot p9s ,c4 ,ea* section has atta*$ !reto a hoop1 or circul>ly-=m$ rib1 ,d1 ! rib pass+ ?r\gh ! section ,b1 & ^! ribs are connect$ toge!r loosely by cords ,e1 :i* run f "o to ! o!r1 z %[n4 ,^! circul> ribs1 ,d1 are design$ to c>ry a plurality ( light pap] disks1 ,f1 :i* are atta*$ at int]vals1 & !y are plac$ at su* angles t !y s]ve z small w+ surfaces or a]oplanes to hold ! /ructure 9 flight4 ,fig4 #cc4 ,ribs ( ,dragon ,kite ,,! ,,malay ,,kite4--,! ,malay kite1 ( :i* ,fig4 #cd %[s ! /ructure1 is m]ely made up ( two cross /icks1 ,a1 ,b1 ! v]tical /rip1 ,a1 be+ b5t & rigid1 :]eas ! cross /ick1 ,b1 is light & yield+1 s t :5 9 flight x w b5d1 z %[n1 & z a result x has wond]ful /ability due to ! dih$ral angles ( ! two surfaces4 ,?is kite requires no tail to give x /ability4 ,fig4 #cd4 ,! ,malay ,kite4 ,,dih$ral ,,angles4--,?is is a t]m to designate a =m ( dispos+ ( ! w+s :i* has be5 f\nd ( great s]vice 9 ! s+le plane ma*9es4 ,a plane :i* is dispos$ at a ris+ angle1 z ,a1 ,a1 ,fig4 #ce1 above ! horizontal l9e1 is call$ dih$ral1 or di$ral4 ,fig4 #ce4 ,dih$ral ,angle4 ,?is arrangem5t 9 monoplanes does away ) ! necessity ( w>p+ ! planes1 or *ang+ !m :ile 9 flight4 ,if1 h[ev]1 ! angle is too great1 ! w9d f ei!r qu>t] is liable to raise ! side t is expos$4 ,,! ,,common ,,kite4--,:ile ! ,malay kite has only two po9ts ( cord atta*m5t1 bo? along ! v]tical rib1 ! common kite1 z %[n 9 ,fig4 #cf1 has a f\r-po9t connection1 to :i* ! fly+ cord is atta*$4 ,s9ce ?is =m has no dih$ral angle1 x is necess>y to supply a tail1 :i* ?us s]ves to keep x 9 equilibrium1 :ile 9 flight4 ,fig4 #cf4 ,common ,kite4 ,v>i\s modifications h gr[n out ( ! ,malay kite4 ,"o ( ^! =ms1 design$ by ,eddy1 is exactly l ! ,malay /ructure1 b in/ead ( hav+ a light flexible cross piece1 x is b5t to resemble a b[1 s t x is rigidly held 9 a b5t position1 in/ead ( p]mitt+ ! w9d to give x ! dih$ral angle4 ,,! ,,b[ ,,kite4--,among ! diff]5t types are ! b[ kite1 ,fig4 #cg1 & ! sexagonal /ructure1 ,fig4 #ch1 ! latt] =m af=d+ an especially l>ge surface4 ,fig4 #cg4 ,b[ ,kite4- ,fig4 #ch4 ,hexagonal ,kite4 ,,! ,,box ,,kite4--,! mo/ m>k$ improvem5t 9 ! =m ( kites 0 made by ,h>greaves1 9 #ahhe1 & call$ ! box kite4 ,x has wond]ful /ability1 & its use1 ) c]ta9 modifications1 9 ,wea!r ,bureau exp]im5ts1 h prov5 its value4 ,x is made 9 ! =m ( two boxes1 ,a1 ,b1 op5 at ! ends1 :i* are secur$ toge!r by means ( longitud9al b>s1 ,c1 t ext5ds f "o to ! o!r1 s t !y are held ap>t a di/ance1 approximately1 equal to ! l5g? ( "o ( ! boxes4 ,fig4 #ci4 ,h>greave ,kite4 ,_! =e & aft /ability is s p]fect t ! fly+ cord ,d is atta*$ at "o po9t only1 & ! sides ( ! boxes provide lat]al /ability to a m>k$ degree4 ,,! ,,voison ,,biplane4--,?is k9d ( kite furni%$ ! sugge/ion = ! ,voison biplane1 :i* 0 "o ( ! e>li] productions 9 fly+ ma*9es4 ,fig4 #dj %[s a p]spective ( ! ,voison plane1 :i* has v]tical planes ,a1 ,a1 at ! ends1 & also int]m$iate curta9s ,b1 ,b4 ,?is 0 f\nd to be rem>kably /able1 b dur+ its turn+ movem5ts1 or 9 high w9ds1 0 n satisfactory1 & = t reason 0 f9ally ab&on$4 ,,lat]al ,,/ability ,,9 ,,kites ,,n ,,conclusive ,,z ,,to ,,planes4--,?is is in/anc$ to %[ t :ile su* a =m is admirably adapt$ = kite purposes1 :]e v]tical curta9s are always 9 l9e ) ! w9d movem5t1 & ! /ructure is held taut by a cord1 ! lat]al effect1 :5 us$ on a ma*9e :i* does n at all times move 9 l9e ) ! mov+ air curr5t4 ,a condition is ?us set up :i* de/roys ! usefulness ( ! box kite =mation4 ,fig4 #dj4 ,voison ,biplane4 ,,! ,,spe> ,,kite4--,?is is a novel kite1 ) rem>kable /ead9ess & is usually made ) ! w+s on ! re> end l>g] ?an ^? on ! =w>d end 7,fig4 #da71 z !reby ! cord ,a c be atta*$ to ! spe> midway betwe5 ! two sets ( w+s4 ,fig4 #da4 ,spe> ,kite4 ,,! ,,cellul> ,,kite4--,foll[+ out ! sugge/ion ( ! ,h>greaves kite1 num]\s =ms embody+ ! pr9ciple ( ! box /ructure 7 made & put on ! m>ket be=e ! a]oplane became a reality4 ,fig4 #db4 ,cellul> ,kite4 ,a /ructure ( ?is =m is illu/rat$ 9 ,fig4 #db4 ,ea* box1 z ,a1 ,b1 has !re9 a plurality ( v]tical & horizontal p>titions1 s t a numb] ( cells are provid$1 ! two cell-l boxes be+ held ap>t by a b> ,c1 axially arrang$4 ,?is type is rem>kably /able1 due to ! small cells1 & kites ( ?is k9d are l>gely us$ = mak+ sci5tific exp]im5ts4 ,,! ,,tetrah$ral ,,kite4--,pr(4 ,bell1 inv5tor ( ! telephone1 gave a great deal ( /udy to kites1 :i* result$ 9 ! tetrah$ral =mation1 z %[n 9 ,fig4 #dc4 ,fig4 #dc4 ,tetrah$ral ,kite4 ,! /ructure1 app>5tly1 is some:at complicat$1 b an exam9ation ( a s+le pair ( blades1 z %[n at ,a1 %[s t x is built up ( triangul>ly-=m$ pieces1 & t ! op5+s betwe5 ! pieces are equal to ! latt]1 !reby provid+ a =m ( kite :i* possesses equilibrium to a great degree4 ,x has nev] be5 tri$ ) p[]1 & x is d\btful :e!r x w\ld be successful z a su/a9+ surface = fly+ ma*9es1 = ! same reasons t caus$ failure ) ! box-l =mation ( ! ,voison ,ma*9e4 ,,! ,,deltoid4--,! deltoid is ! simple/1 & ! mo/ easily con/ruct$ ( all ! kites4 ,x is usually made f /iff c>dbo>d1 ,a-%ap$ 9 outl9e1 z %[n 9 ,figs4 #dd & #de1 & b5t along a c5tral l9e1 z at ,a1 =m+ two w+s1 ea* ( :i* is a "r-angl$ triangle4 ,fig4 #dd4 & #de4 ,deltoid ,=mation4 ,! peculi>ity ( ?is =mation is1 t x has rem>kable /ability :5 us$ z a kite1 ) ei!r end =emo/4 ,if a small weight is plac$ at ! po9t$ end1 & x is project$ ?r\gh ! air1 x w fly /raight1 & is b little affect$ by cross curr5ts4 ,,! ,,dunne ,,fly+ ,,ma*9e4--,a top view ( ?is biplane is %[n 9 ,fig4 #df4 ,! ,a-%ap$ disposition ( ! planes1 gives x good lat]al /ability1 b x has ! disadvantage "u :i* all a]oplanes labor1 t ! entire body ( ! ma*9e mu/ move on a =e & aft v]tical plan 9 ord] to asc5d or desc5d4 ,fig4 #df4 ,! ,dunne ,bi-plane4 ,?is is a true deltoid =mation1 z ! angle ( incid5ce ( ! planes is s dispos$ t :5 ! planes are horizontal f end to end1 ! incl9ation is su* z to make x simil> to ! deltoid kite ref]r$ to4 ,,rotat+ ,,kite4--,a type ( kite unlike ! o!rs illu/rat$ is a rotat+ /ructure1 :i* gives great /ability1 due to ! gyroscopic action on ! support+ surfaces4 ,fig4 #dg %[s a side view ) ! top 9 section4 ,! support+ surface is umbrella-%ap$4 ,9 fact1 ! ord9>y umbrella w answ] if n di%$ too mu*4 ,an angul>ly-b5t piece ( wire ,a1 provid$ ) loops ,b1 ,b1 at ! ends1 s]ve z be>+s = ! h&le ( ! umbrella4 ,at ! b5d ( ! wire loop ,c1 ! cord ,d is atta*$4 ,! l[] side ( ! umbrella top has cup-%ap$ pockets ,e1 ne> ! m>g91 s arrang$ t _! op5 ends project 9 ! same direction1 & ! w9d cat*+ !m rotates ! circul> plane4 ,fig4 #dg4 ,rotable ,umbrella ,kite4 ,,kite ,,pr9ciples4--,a c>eful /udy ( ! examples "h giv51 w impress ! novice ) "o important fact1 :i*1 9 its effect has a m important be>+ on successful flight1 ?an all ! bird /udy & speculations conc]n+ its my/]ies4 ,?is fact1 9 ess5ce1 is1 t ! angle ( ! kite is ! great factor 9 flight next to ! p[] necess>y to hold x4 ,aside f ?is1 ! comp>ison betwe5 kites & a]oplanes is ( no practical value4 ,disreg>d+ ! elem5t ( mom5tum1 ! drift ( a ma*9e aga9/ a w9d1 is ! same1 dynamically1 z a plane at re/ ) ! w9d mov+ pa/ x4 ,b !re is ?is pron\nc$ diff]5ce3 ,! cord :i* supports ! kite holds x s t ! p[] is 9 "o direction only4 ,:5 a side gu/ ( w9d /rikes ! kite x is mov$ lat]ally1 9 sympa?y ) ! kite1 h5ce ! problem ( lat]al displacem5t is n ! same z ) ! a]oplane4 ,,lat]al ,,/ability ,,9 ,,kites4--,9 ! latt] ! p[] is def9itely fix$ ) relation to ! ma*9e itself1 & if we %\ld assume t a plane ) a p[] on x suffici5t to ma9ta9 a flight ( #dj miles an h\r1 %\ld meet a w9d mov+ at ! same spe$1 ! ma*9e w\ld be /ation>y 9 space4 ,su* a condition w\ld be ! same1 s f> z ! angles ( ! planes are conc]n$1 ) a kite held by a /r+1 b !re all simil>ity 9 action ends4 ,! /abiliz+ quality ( ! kite may be p]fect1 z ! w9d v>ies f side to side1 b ! a]oplane1 be+ free1 moves to ! "r or to ! left1 & does n adju/ itself by means ( a fix$ po9t1 b by a movable "o4 ,,simil>ity ,,( ,,=e ,,& ,,aft ,,control4--,=e & aft1 h[ev]1 ! kite & a]oplane act ! same4 ,fig4 #dh %[s a diagram :i* illu/rates ! =ces :i* act on ! kite1 & by means ( :i* x adju/s its angle automatically4 ,let u assume t ! kite ,a is fl[n f a cord ,b1 s t its angle is #bb #a_/b degrees1 ! w9d be+ #ae miles p] h\r to ma9ta9 ! cord ,b at t angle4 ,:5 ! w9d increases to #bj miles an h\r !re is a correspond+ly great] lift aga9/ ! kite4 ,fig4 #dh4 ,action ( ,w9d =ces on ,kite4 ,z its angle is fix$ by means ( ! loop ,c1 x _c *ange its angle ) ref]5ce to ! cord1 or indep5d5tly ( x1 & its only c\rse is to move up high] & assume ! position %[n by ! figure at ,d1 & ! angle ( incid5ce ( ! kite is !re=e *ang$ to #ae degrees1 or ev5 to #aj degrees4 ,9 ! case ( ! a]oplane ! effect is simil> f ! /&po9t ( p[] & disposition ( ! planes4 ,if x has suffici5t p[]1 & ! angle ( ! planes is n *ang$1 x w asc5d2 if ! planes are *ang$ to #ae degrees to correspond ) ! kite angle x w rema9 /ation>y4 ,,glid+ ,,flight4--,! e>lie/ attempt to fly by glid+ is attribut$ to ,oliv]1 a ,monk ( ,malmesbury :o1 9 #ajfe prep>$ artificial w+s1 & ) !m jump$ f a t[]1 be+ injur$ 9 ! exp]im5t4 ,ne>ly #gjj ye>s lat]1 9 #ahja1 ,resni]1 a ,fr5*man1 conduct$ exp]im5ts ) v>y+ results1 foll[$ by ,b]bl+]1 9 #ahdb1 & ,le,bris1 a ,fr5* sailor1 9 #ahef4 ,9 #ahhd1 ,j4 ,j4 ,montgom]y1 ( ,cali=nia1 design$ a successful glid]1 & 9 #ahhi ,otto & ,gu/av ,lili5?al made ! mo/ ext5d$ te/s1 9 ,g]many1 & became exp]ts 9 h&l+ glid]s4 ,pil*]1 9 ,engl&1 0 ! next to take up ! subject1 & 9 #ahic made _m successful glides1 all ( ! =ego+ ma*9es be+ s+le plane surfaces1 simil> to ! monoplane4 ,long prior to #ahif ,octave ,*anute1 an eng9e]1 gave ! subject mu* /udy1 & 9 t ye> made _m rem>kable flights1 develop+ ! d\ble plane1 n[ kn[n z ! biplane4 ,he 0 an ard5t believ] 9 ! ability ( man to fly by so>+ means1 & )\t us+ p[] = ! purpose4 ,x is d\btful :e!r glid]s contribut$ mu* to ! art 9 ! direction ( lat]ally /abiliz+ a]oplanes4 ,!y taught useful lessons ) respect to area & =e & aft control4 ,! kite gave ! fir/ impulse to seek out a means = giv+ equilibrium to planes1 & ,montgom]y made a kite ) w>p+ w+s z e>ly z #ahhd4 ,p5aud1 a ,fr5*man1 9 #ahgb1 made a model a]oplane :i* _h ! /abiliz+ means 9 ! tail4 ,all ^! grew out ( kite exp]im5ts2 & all glid]s foll[$ ! kite con/ruction1 or ! pr9ciples involv$ 9 !m1 s t1 really1 !re is b "o int]v5+ /ep betwe5 ! kite & ! fly+ ma*9e1 z we "k x1 ! latt] be+ m]ely kites ) p[] atta*$1 z sub/itutes = ! cords4 ,,"o ,,( ,,! ,,uses ,,( ,,glid] ,,exp]im5ts4-- ,!re is "o direction 9 :i* glid]s are valuable to ! boy & to ! novice :o are int]e/$ 9 aviation4 ,he may sp5d a lifetime 9 glid+ & n advance 9 ! art4 ,x is que/ionable :e!r 9 a sci5tific way x w be ( any s]vice to him2 b exp]im5ts ( ?is "* give confid5ce1 ! ability to quickly grasp a situation1 & x w ?us tea* self reliance 9 em]g5cies4 ,:5 9 a glid] quick ?9k+ is necess>y4 ,! ability to %ift f "o position to ano!r2 to apply ! weight :]e requir$ in/antane\sly2 to be able dur+ ! brief excit+ mom5t ( flight to "k j :at to d1 requires al]tness4 ,"s are s w$d$ to ! e>? t slight elevation di/urbs !m4 ,! s5sation 9 a glid] :ile 9 flight is unlike any o!r exp]i5ce4 ,x is l rid+ a lot ( t5se spr+s1 & ! exhil>ation 9 glid+ d[n ! side ( a hill1 ) ! feet free & body susp5d$1 is q diff]5t f rid+ 9 an a]oplane ) p[] atta*$4 ,,h9ts ,,9 ,,glid+4--,x seems to be a difficult matt] to give any advice 9 ! art ( glid+4 ,x is a feat :i* seems to necessitate exp]im5t f fir/ to la/4 ,dur+ ! hundr$s ( te/s p]sonally made1 & aft] witness+ ?\s&s ( attempts1 !re seems to be only a few sugge/ions or possible directions 9 :i* caution might be (f]$4 ,fir/1 9 respect to ! position ( ! body at ! mom5t ( laun*+4 ,! glid] is usually s made t 9 c>ry+ x1 prep>atory to mak+ ! run & ! leap requir$ to glide1 x is held s t x balances 9 ! h&s4 ,n[ ! c5t] ( air pressure 9 glid+ may n be at ! same po9t z its su/a9+ weight :5 held by ! h&1 & fur!rmore1 z ! arm-pits1 by :i* ! body ( ! exp]im5t] are held :ile glid+1 are n at ! same po9t1 b to ! re> ( ! h&s1 ! mom5t ! glid] is laun*$ too great a weight is br\ght to ! re> m>g9 ( ! planes1 h5ce its =w>d end lifts up4 ,?is condition w soon manife/ itself1 & be correct$ by ! exp]im5t]2 b !re is ano!r difficulty :i* is n s easy to discov] & s quick to rem$y1 & t is ! sw+ ( ! legs ! mom5t ! op]ator leaves ! gr\nd4 ,! exp]im5t] le>ns1 aft] _m attempts1 t glid+ is a matt] ( a few feet only1 & he anticipates l&+ too soon1 & ! mom5t he leaps f ! gr\nd ! legs are swung =w>dly ready to alight4 ,?is is done unconsci\sly1 j z a jump] sw+s 8 legs =w>dly 9 ! act ( alight+4 ,su* a motion naturally di/urbs ! =e & aft /ability ( ! glid+ ma*9e1 by tilt+ up ! =w>d m>g91 & x banks aga9/ ! air1 in/ead ( glid+4 ,! con/ant fe> ( all glid]s is1 t ! ma*9e w po9t d[nw>dly1 & 8 motion1 z well z ! position ( ! body1 t5d to %oot x upw>dly1 in/ead4 ,,*apt] ,,ix ,,a]oplane ,,con/ruction ,z may be inf]r$ f ! =ego+ /atem5ts1 !re are no def9ite rules = ! con/ruction ( ei!r type ( fly+ ma*9e1 z ! fly+ models v>y to su* an ext5t t x is difficult to take ei!r ( !m z a model to repres5t ! pref]r$ type ( con/ruction4 ,,lat]al1 ,,& ,,=e ,,& ,,aft4--,! t]m lat]al %\ld be und]/ood1 z appli$ to a]oplanes4 ,x is always us$ to designate ! direction at "r angles to ! movem5t ( ! ma*9e4 ,=e & aft is a m>9e t]m mean+ l5g?wise1 or f front to re>1 h5ce is always at "r angles to ! lat]al direction4 ,! t]m transv]se is equival5t to lat]al1 9 fly+ ma*9e p>lance1 b !re is ?is di/9ction3 ,transv]se has ref]5ce to a ma*9e or object :i*1 l ! ma9 planes ( an a]oplane1 are broad]1 7t is1--f end to end7 ?an _! l5g?1 7f front to re>74 ,on ! o!r h&1 lat]al has ref]5ce to side bran*es1 z1 = in/ance1 ! monoplane w+s1 :i* bran* out f ! sides ( ! =e & aft body4 ,,/ability ,,& ,,/abilization4--,^! t]ms con/antly appe> 9 describ+ ma*9es & _! op]ations4 ,if ! fly+ /ructure1 :atev] x may be1 has means :]eby x is kept f rock+ f side to side1 x has /ability1 :i* is usually designat$ z lat]al /ability4 ,! me*anism = do+ ?is is call$ a /abiliz]4 ,,! ,,wright ,,sy/em4--,! ,wright ma*9e has ref]5ce solely to ! matt] ( lat]ally controll+ ! fly+ /ructure1 & does n p]ta9 to ! =m or %ape ( ! planes4 ,9 ,fig4 #di ,a designates ! upp] & l[] planes ( a ,wright ma*9e1 ) ! peculi> r\nd$ ends4 ,! ends ( ! planes are s arrang$ t ! re> m>g9s may be rais$ or l[]$1 indep5d5tly ( ! o!r portions ( ! planes1 :i* are rigid4 ,?is movem5t is indicat$ 9 sket* #a1 :]e ! movable "p ,b is1 z we might say1 h+$ along ! l9e ,c4 ,! dott$ l9e ,d on ! "r h& end1 %[s h[ ! section is depress$1 :ile ! dott$ l9es ,e at ! left h& end %[s ! section rais$4 ,x is obvi\s t ! d[nturn$ ends1 z at ,d1 w give a positive angle at "o end ( ! planes1 & ! upturn$ w+s ,e at ! o!r end w give a negative angle1 & ?us cause ! "r h& end to raise1 & ! o!r end to move d[nw>dly1 z ! ma*9e moves =w>dly ?r\gh ! air4 ,,controll+ ,,! ,,w>p+ ,,ends4--,orig9ally ! ,wrights controll$ ^! w>p+ sections by means ( a cradle occupi$ by ! aviator1 s t ! cradle w\ld move or rock1 dep5d5t on ! tilt ( ! ma*9e4 ,?is 0 :at 0 t]m$ automatic control4 ,?is 0 f\nd to be unsatisfactory1 & ! control has n[ be5 plac$ s t x connects ) a lev] & is op]at$ by ! aviator1 & is call$ ,manually-op]at$ control4 ,9 all =ms ( control ! w+s on "o side are depress$ on "o side & correspond+ly elevat$ on ! o!r4 ,,! ,,curtis ,,w+s4--,curtis has small w+s1 or ail]ons1 int]m$iate ! support+ surfaces1 & at _! extremities1 z %[n 9 sket* #b4 ,^! are controll$ by a %\ld] rack or sw++ frame op]at$ by ! driv]1 s t ! body 9 sw++ lat]ally w *ange ! two w+s at ! same "t1 b ) angles 9 diff]5t directions4 ,,! ,,f>man ,,ail]ons4--,f>man's disposition is some:at diff]5t1 z %[n 9 sket* #c4 ,! w+s are h+$ to ! upp] planes at _! re> edges1 & ne> ! extremities ( ! planes4 ,op]at+ wires lead to a lev] )9 rea* ( ! aviator1 &1 by ?is means1 ! w+s are held at any desir$ angle1 or *ang$ at w4 ,! difficulty ( us+ any p>ticul> model1 is true1 also1 ( ! arrangem5t ( ! =e & aft control1 z well z ! means = lat]ally /abiliz+ x4 ,9 view ( ?is we %all submit a g5]al =m1 :i* may be dep>t$ f at w4 ,,features ,,well ,,develop$4--,c]ta9 features are fairly well develop$1 h[ev]4 ,"o is ! angle ( ! support+ plane1 ) ref]5ce to ! frame itself2 & ! o!r is ! height at :i* ! tail & rudd] %\ld be plac$ above ! surface ( ! gr\nd :5 ! ma*9e is at re/4 ,,depress+ ,,! ,,re> ,,end4--,?is latt] is a matt] :i* mu/ be tak5 into consid]ation1 because 9 initiat+ flight ! re> end ( ! frame is depress$ 9 ord] to give a suffici5t angle to ! support+ planes s z to be able to inaugurate flight4 ,9 ord] to comm5ce build+ we %\ld h "s def9ite idea ) respect to ! p[]1 z ?is w1 9 a measure1 det]m9e ! area ( ! support+ surfaces1 z a :ole1 & f ?is ! sizes ( ! diff]5t planes may be det]m9$4 ,,det]m9+ ,,! ,,size4--,suppose we decide on #cjj squ>e feet ( su/a9+ surface4 ,?is may require a #cj1 a #dj or a #ej horse p[] motor1 dep5d5t on ! spe$ requir$1 & mu* high] p[] has be5 us$ on t area4 ,h[ev]1 let u assume t a =ty horse p[] motor is available1 our #cjj squ>e feet ( surface may be put into two planes1 ea* hav+ #aej squ>e feet ( surface1 :i* w\ld make ea* #e' by #cj' 9 size2 or1 x may be decid$ to make ! planes n>r[]1 & proportionally long]4 ,?is is immat]ial4 ,! %ort] ! planes transv]sely1 ! great] w be ! /ability1 & ! wid] ! planes ! less w be ! lift1 comp>atively4 ,,rule ,,= ,,plac+ ,,! ,,planes4--,! rule = plac+ ! planes is to place !m ap>t a di/ance equal to ! wid? ( ! planes !mselves1 s t if we decide on mak+ !m five feet wide1 !y %\ld be plac$ at lea/ five feet ap>t4 ,?is rule1 :ile x is an admirable "o = sl[ movem5ts or :5 />t+ flight1 is n ( any advantage :ile 9 rapid flight4 ,if ! ma*9e is made ) front & re> horizontally-dispos$ rudd]s1 or elevators1 !y also s]ve z su/a9+ surfaces1 :i*1 = ! pres5t w be disreg>d$4 ,lay (f a squ>e ,a1 ,fig4 #di;a1 9 :i* ! v]tical l9es ,b1 ,b1 & ! horizontal l9es ,c1 ,c1 are #e' long1 & draw a cross ,d )9 ?is1 ! l9es runn+ diagonally f ! corn]s4 ,n[ /ep (f f ! c5t] cross l9e ,d1 ?ree spaces1 ea* five feet long1 to a po9t ,e1 & jo9 ?is po9t by means ( upp] & l[] b>s ,f1 ,g1 ) ! upp] & l[] planes1 s z to =m ! tail frame4 ,fig4 #di;a4 ,rule = spac+ ,planes4 ,z %[n 9 ,fig4 #ej1 ! planes %\ld n[ be indicat$1 & plac$ at an angle ( ab\t #h degrees angle1 :i* are illu/rat$1 ,h be+ ! upp] & ,i ! l[] plane4 ,midway betwe5 ! =w>d edges ( ! two planes1 is a horizontal l9e ,j1 ext5d+ =w>dly1 & by /epp+ (f ! wid? ( two planes1 a po9t ,k is made1 :i* =ms ! apex ( a frame ,l1 ! re> ends ( ! b>s be+ atta*$ to ! respective planes ,h1 ,i1 at _! =w>d edges4 ,fig4 #ej4 ,frame ( ,control ,planes4 ,fig4 #ea4 & ,fig4 #eb4 ,,elevat+ ,,planes4--,we mu/ n[ h ! g5]al side elevation ( ! frame1 ! planes1 _! angles1 ! tail & ! rudd] support1 & ! frame = ! =w>d elevator4 ,to ?is may be add$ ! =w>d elevat+ plane ,l1 ! re> elevator1 or tail ,m1 & ! v]tical /e]+ rudd] ,n4 ,! frame :i* supports ! /ructure ?us describ$1 may be made 9 a v>iety ( ways1 ! object be+ to provide a resili5t connection = ! re> :eel ,o4 ,fig4 #eb %[s a frame :i* is simple 9 con/ruction & easily atta*$4 ,! l[] =e & aft side b>s ,p h ! s+le front :eel axle at ! =w>d end1 & ! aft d\ble :eels at ! re> end1 a flexible b> ,q1 runn+ f ! re> :eel axle to ! =w>d end ( ! l[] plane4 ,a compression spr+ ,r is also m\nt$ betwe5 ! b> & re> end ( ! l[] plane to take ! %ock ( l&+4 ,! =w>d end ( ! b> ,p has a brace ,s ext5d+ up to ! front edge ( ! l[] plane1 & ano!r brace ,t connects ! b>s ,p1 ,s1 ) ! end ( ! =w>dly- project+ frame4 ,fig4 #ec4 ,plan view4 ,! full page view1 ,fig4 #ec1 repres5ts a plan view1 ) "o ( ! w+s cut away1 %[+ ! g5]al arrangem5t ( ! frame1 & ! ?ree :eels requir$ = support1 toge!r ) ! brace b>s ref]r$ to4 ,! necessity ( ! re> end elevation w n[ be ref]r$ to4 ,! tail ne$ n1 necess>ily1 be locat$ at a po9t on a horizontal l9e betwe5 ! planes4 ,x may be high]1 or l[] ?an ! planes1 b x %\ld n be 9 a position to t\* ! gr\nd :5 ! ma*9e is ab\t to asc5d4 ,fig4 #ed4 ,alight+4 ,! angle ( asc5sion 9 ! planes ne$ n exce$ #be degrees s ! frame does n require an angle ( m ?an #ag degrees4 ,?is is %[n 9 ,fig4 #ed1 :]e ! ma*9e is 9 a position ready to take ! air at t angle1 leav+ ample room = ! /e]+ rudd]4 ,,action ,,9 ,,alight+4--,also1 9 alight+1 ! ma*9e is bank$1 practically 9 ! same position ?us %[n1 s t x alights on ! re> :eels ,o4 ,! motor ,u is usually m\nt$ s its %aft is midway betwe5 ! planes1 ! propell] ,v be+ connect$ directly ) ! %aft1 & be+ beh9d ! planes1 is on a m$ial l9e ) ! ma*9e4 ,! control planes ,l1 ,m1 ,n1 are all connect$ up by means ( flexible wires ) ! aviator at ! set ,w1 ! atta*m5ts be+ ( su* a "* t _! arrangem5t w readily sugge/ !mselves to ! novice4 ,,! ,,monoplane4--,f a spectacul> /&po9t a monoplane is ! ideal fly+ ma*9e4 ,x is graceful 9 outl9e1 & f ! fact t x closely approa*es ! =m ( ! natural fly]1 seems to be be/ adapt$ z a type1 comp>$ ) ! biplane4 ,,! ,,common ,,fly4--,s _m birds h be5 cit$ 9 support ( ! v>i\s fly+ !ories t ! h\se fly1 z an example has be5 disreg>d$4 ,we are prone to ov]look ! small insect1 b x is1 nev]!less1 a sample :i* is j z pot5t to %[ ! effici5cy ( w+ surface z ! condor or ! vulture4 ,! fly has great] mobility ?an any o!r fly+ creature4 ,by ! comb9$ action ( its legs & w+s x c spr+ eighte5 in*es 9 ! t5? ( a second2 & :5 9 flight c *ange its c\rse in/antane\sly4 ,if a sp>r[ _h ! same dext]ity1 proportionally1 x c\ld make a flight ( #hjj feet 9 ! same "t4 ,! po/]ior legs ( ! fly are ! same l5g? z its body1 :i* enable x to spr+ f its p]* ) amaz+ facility4 ,fig4 #ee4 ,common ,fly4 ,out/ret*$ ,w+s4 ,! w+ surface1 proportion$ to its body & weight1 is no less a matt] = wond] & consid]ation4 ,9 ,fig4 #ee is %[n ! outl9es ( ! fly ) out/ret*$ w+s4 ,fig4 #ef repres5ts x ) ! w+ fold$1 & ,fig4 #eg is a view ( a w+ ) ! relative size ( ! top ( ! body %[n 9 dott$ l9es4 ,fig4 #ef4 ,common ,fly4 ,fold$ ,w+s4 ,! fir/ ?+ t mu/ attract att5tion1 aft] a c>eful /udy is ! relative size ( ! body & w+ surface4 ,ea* w+ is slightly small] ?an ! upp] surface ( ! body1 & ! ?ickness ( ! body is equal to ea* w+ spread4 ,fig4 #eg4 ,relative size ( w+ & body4 ,! weight1 comp>$ ) su/a9+ surface1 if express$ 9 und]/&able t]ms1 w\ld be equal to sixty p\nds = e squ>e foot ( surface4 ,,/ream ,,l9es4--,! next obs]vation is1 t :at are call$ /ream l9es d n exi/ 9 ! fly4 ,its head is z l>ge 9 cross section z its body1 ) ! slighte/ sugge/ion only1 ( a po9t$ end4 ,its w+s are p]fectly flat1 =m+ a true plane1 n di%$1 or provid$ ) a cambre1 ev51 t upw>d curve1 or bulge on ! top ( ! a]oplane surface1 :i* seems to possess su* a fasc9ation = _m bird flight advocates4 ,x w also be obs]v$ t ! w+ connection ) ! body is =w>d ( ! l9e ,a1 :i* repres5ts ! po9t at :i* ! body w balance itself1 & ?is l9e passes ?r\gh ! w+s s t !re is an equal am\nt ( support+ surface =e & aft ( ! l9e4 ,aga91 ! w+ atta*m5t is at ! upp] side ( ! body1 & ! v]tical dim5sion ( ! body1 or its ?ickness1 is equal to f\r-fif?s ( ! l5g? ( he w+4 ,! w+ socket p]mits a motion simil> to a univ]sal jo9t1 ,fig4 #ee %[+ h[ ! inn] end ( ! w+ has a d[nw>d b5d :]e x jo9s ! back1 z at ,b4 ,,! ,,monoplane ,,=m4--,= ! purpose ( mak+ comp>isons ! illu/rations ( ! monoplane %[ a ma*9e ( #cjj squ>e feet ( surface1 :i* necessitates a w+ spread ( =ty feet f tip to tip1 s t ! g5]al dim5sions ( ea* %\ld be #ah #a_/b feet by #h #a_/b feet at its wide/ po9t4 ,fir/ draw a squ>e =ty feet ea* way1 z 9 ,fig4 #eh1 & ?r\gh ?is make a horizontal l9e #a1 & f\r int]m$iate v]tical l9es are !n drawn1 z #b1 #c1 #d1 #e1 ?us provid+ five divisions1 ea* eight feet wide4 ,9 ! fir/ division ! planes ,a1 ,b1 are plac$1 & ! tail1 or elevator ,c1 is "o-half ! wid? ( ! la/ division4 ,fig4 #eh4 ,plan ( ,monoplane4 ,! frame is #c #a_/b feet wide at its =w>d end1 & tap]s d[n to a po9t at its re> end1 :]e ! v]tical control plane ,d is h+$1 & ! cross /ruts ,e1 ,e1 are plac$ at ! division l9es #c1 #d1 #e4 ,! angles ( ! planes1 ) relation to ! frame1 are usually great] ?an 9 ! biplane1 = ! reason t ! long tail plane requires a great] angle to be giv5 to ! planes :5 aris+2 or1 in/ead ( ?is1 ! planes ,a1 ,b1 are m\nt$ high en\gh to p]mit ( suffici5t angle = initiat+ flight )\t injur+ ! tail ,d4 ,"s monoplanes are built s !y h a support on :eels plac$ =e & aft4 ,9 o!rs ! tail is support$ by curv$ skids1 z %[n at ,a1 ,fig4 #ei1 9 :i* case ! =w>d support+ :eels are locat$ directly b5ea? ! planes4 ,z ! planes are at ab\t eighte5 degrees angle1 relative to ! frame1 & ! tail plane ,b is at a slight negative angle ( incid5ce1 z %[n at ! "t :5 ! eng9e is />t$1 ! air ru%+ back f ! propell]1 elevates ! tail1 & z ! ma*9e moves =w>dly ov] ! gr\nd1 ! tail raises /ill high]1 s z to give a less angle ( incid5ce to ! planes :ile skimm+ along ! surface ( ! gr\nd4 ,fig4 #ei4 ,side ,elevation1 ,monoplane4 ,9 ord] to m\nt1 ! tail is sudd5ly turn$ to assume a %>p negative angle1 ?us sw++ ! tail d[nw>dly1 & ?is increases ! angle ( planes to su* an ext5t t ! ma*9e leaves ! gr\nd1 aft] :i* ! tail is br\ght to ! prop] angle to assure horizontal flight4 ,! draw+ %[s a skid at ! =w>d end1 atta*$ to ! frame :i* c>ries ! :eels4 ,! :eels are m\nt$ b5ea? spr+s s t :5 ! ma*9e alights ! spr+s yield suffici5tly to p]mit ! skids to /rike ! gr\nd1 & !y1 !re=e1 act z brakes1 to prev5t ! ma*9e f travel+ too f>4 ,,*apt] ,x ,,p[] ,,& ,,its ,,application ,,?is is a phase ( ! fly+ ma*9e :i* has ! greate/ int]e/ to ! boy4 ,he in/9ctively sees ! direction 9 :i* ! ma*9e has its life1--its mov+ pr9ciple4 ,planes h _! fasc9ation1 & propell]s _! my/]i\s elem5ts1 b p[] is ! great & absorb+ "q ) him4 ,we %all try to make its application pla9 9 ! foll[+ pages4 ,we h no?+ to d "h ) ! con/ruction & op]ation ( ! motor itself1 z1 to d t ju/ice1 w\ld require pages4 ,,features ,,9 ,,p[] ,,application4--,x w be m directly to ! po9t to consid] ! foll[+ features ( ! p[] & its application3 #a4 ,! am\nt ( p[] necess>y4 #b4 ,h[ to calculate ! p[] appli$4 #c4 ,its m\nt+4 ,,:at ,,am\nt ,,( ,,p[] ,,is ,,necess>y4--,9 ! consid]ation ( any p[] plant c]ta9 calculations mu/ be made to det]m9e :at is requir$4 ,a horse p[] means ! lift+ ( a c]ta9 weight1 a def9ite di/ance1 )9 a specifi$ "t4 ,if ! weight ( ! vehicle1 ) its load1 are kn[n1 & its resi/ance1 or ! "* ( ! roadway is und]/ood1 x is a comp>atively easy matt] to calculate j h[ mu* p[] mu/ be ex]t$ to ov]come t resi/ance1 & move ! vehicle a c]ta9 spe$4 ,9 a fly+ ma*9e ! same ?+ is true1 b :ile ^! problems may be kn[n 9 a g5]al way1 ! aviator has sev]al unkn[n elem5ts ev] pres5t1 :i* make e/imates difficult to solve4 ,,! ,,pull ,,( ,,! ,,propell]4--,two su* factors are ev] pres5t4 ,! fir/ is ! propell] pull4 ,! en]gy ( a motor1 :5 put into a propell]1 gives a pull ( less ?an eight p\nds = e horse p[] ex]t$4 ,,foot ,,p\nds4--,! "w produc$ by a motor is calculat$ 9 ,foot ,p\nds4 ,if #eej p\nds %\ld be lift$1 or pull$1 "o foot 9 "o second ( "t1 x w\ld be equal to "o horse p[]4 ,b "h we h a case :]e "o horse p[] pulls only eight p\nds1 a di/ance ( "o foot )9 "o second ( "t1 & we h utiliz$ less ?an "o sixty-fif? ( ! actual en]gy produc$4 ,,small ,,am\nt ,,( ,,p[] ,,available4--,?is is due to two ?+s3 ,fir/1 ! exce$+ lightness ( ! air1 & its great ela/icity2 &1 second1 ! difficulty ( mak+ a surface :i*1 :5 x /rikes ! air1 w get a suffici5t grip to effect a prop] pull4 ,n[ x mu/ be obvi\s1 t :]e only su* a small am\nt ( en]gy c be made available1 9 a m$ium z elusive z air1 ! lea/ *ange1 or =m1 ( ! propell]1 mu/ h an important be>+ 9 ! g5]al results4 ,,high ,,propell] ,,spe$ ,,important4--,fur!rmore1 all ?+s consid]$1 high spe$ is important 9 ! rotation ( ! propell]1 up to a c]ta9 po9t1 beyond :i* ! pull decreases 9 proportion to ! spe$4 ,high spe$ makes a vacuum beh9d ! blade & ?us decreases ! effective pull ( ! succe$+ blade4 ,,wid? ,,& ,,pit* ,,( ,,blades4--,if ! blade is too wide ! spe$ ( ! eng9e is cut d[n to a po9t :]e x _c ex]t ! prop] en]gy2 if ! pit* is v small !n x mu/ turn fur!r to get ! same ?ru/1 s t ! relation ( diamet]1 pit* & spe$1 are ?ree problems f> f be+ solv$4 ,x may be a "q :e!r ! propell] =m1 z we n[ "k x1 is any?+ l ! true or ultimate %ape1 :i* w "s day be discov]$4 ,,effect ,,( ,,increas+ ,,propell] ,,pull4--,if ! pres5t pull c\ld be d\bl$ :at a wond]ful revolution w\ld take place 9 a]ial navigation1 & if x 7 possible to get only a qu>t] ( ! effective pull ( an eng9e1 ! results w\ld be s /up5d\s t ! pres5t me?od ( fly+ w\ld seem l *ild's play 9 comp>ison4 ,x is 9 ?is v matt]1--! application ( ! p[]1 t ! bird1 & o!r fly+ creatures s f> excel :at man has done4 ,calculations made ) birds z samples1 %[ t _m ( !m are able to fly ) su* a small am\nt ( p[] t1 if ! same en]gy %\ld be appli$ to a fly+ ma*9e1 x w\ld sc>cely drive x along ! gr\nd4 ,,disposition ,,( ,,! ,,planes4--,! second factor is ! disposition or arrangem5t ( ! planes ) relation to ! weight4 ,let u illu/rate ?is ) a concrete example3 ,we h an a]oplane ) a su/a9+ surface ( #cjj squ>e feet :i* weighs #ijj p\nds1 or #cj p\nds p] squ>e foot ( surface4 ,,diff]5t ,,spe$s ,,) ,,same ,,p[]4--,n[1 we may be able to d two ?+s ) an air%ip "u ^? conditions4 ,x may be propell$ ?r\gh ! air ?irty miles an h\r1 or sixty miles1 ) ! exp5diture ( ! same p[]4 ,an automobile1 if propell$ at sixty1 in/ead ( ?irty miles an h\r1 w\ld require an additional p[] 9 do+ s1 b an air%ip acts diff]5tly1 )9 c]ta9 limitations4 ,:5 x is fir/ set 9 motion its effective pull may n be equal to f\r p\nds = ea* horse p[]1 due to ! sl[ spe$ ( ! propell]1 & also ow+ to ! great angle ( incid5ce :i* resi/s ! =w>d movem5t ( ! %ip4 ,,increase ,,( ,,spe$ ,,adds ,,to ,,resi/ance4--,f9ally1 z spe$ increases1 ! angle ( ! planes decrease1 resi/ance is less1 & up to a c]ta9 po9t ! pull ( ! propell] increases2 b beyond t ! vacuum beh9d ! blades becomes s great z to br+ d[n ! pull1 & !re is ?us a balance1--a sort ( mutual gov]n+ motion :i*1 toge!r1 det]m9e ! ultimate spe$ ( ! a]oplane4 ,,h[ ,,p[] ,,decreases ,,) ,,spe$4--,if n[1 ) ! same propell]1 ! spe$ %\ld be d\bl$1 ! %ip w\ld g no fa/]1 because ! bite ( ! propell] on ! air w\ld be ineffective1 h5ce x w be se5 t x is n ! am\nt ( p[] 9 itself1 t det]m9es ! spe$1 b ! %ape ( ! propell]1 :i* mu/ be s made t x w be mo/ effective at ! spe$ requir$ = ! %ip4 ,:ile t is true :5 spe$ is ! matt] ( greate/ importance1 x is n ! case :]e x is desir$ to effect a laun*+4 ,9 t case ! propell] mu/ be made s t its greate/ pull w be at a sl[ spe$4 ,?is means a wid] blade1 & a great] pit*1 & a comp>atively great] pull at a sl[ spe$4 ,no su* consid]ation ne$ be giv5 to an automobile4 ,! con/ant accretion ( p[] adds to its spe$4 ,9 fly+ ma*9es ! aviator mu/ always consid] "s companion factor :i* mu/ be consult$4 ,,h[ ,,to ,,calculate ,,! ,,p[] ,,appli$4--,9 a previ\s *apt] ref]5ce 0 made to a plane at an angle ( =ty-five degrees1 to :i* two scales 7 atta*$1 "o to get its horizontal pull1 or drift1 & ! o!r its v]tical pull1 or lift4 ,,pull+ ,,aga9/ ,,an ,,angle4--,let u take ! same example 9 our a]oplane4 ,assum+ t x weighs #ijj p\nds1 & t ! angle ( ! planes is =ty-five degrees4 ,if we suppose t ! air b5ea? ! plane is a solid1 & frictionless1 & a pair ( scales %\ld draw x up ! incl9e1 ! pull 9 do+ s w\ld be "o-half ( its weight1 or #dej p\nds4 ,x mu/ be obvi\s1 !re=e1 t its =ce1 9 mov+ d[nw>dly1 along ! surface ,a1 ,fig4 #fj1 w\ld be #dej p\nds4 ,! incl9e ?us %[n has !reon a weight ,b1 m\nt$ on :eels a1 & ! =w>dly-project+ cord repres5ts ! p[]1 or propell] pull1 :i* mu/1 !re=e1 ex]t a =ce ( #dej p\nds to keep x 9 a /ation>y position aga9/ ! surface ,a4 ,9 su* a case ! ?ru/ along ! diagonal l9e ,e w\ld be #ijj p\nds1 be+ ! composition ( ! two =ces pull+ along ! l9es ,d1 ,f4 ,,! ,,horizontal ,,& ,,v]tical ,,pull4--,n[ x mu/ be obvi\s1 t if ! incl9e takes half ( ! weight :ile x is be+ drawn =w>dly1 9 ! l9e ( ,d1 if we _h a propell] draw+ along t l9e1 :i* has a pull ( #dej p\nds1 x w\ld ma9ta9 ! plane 9 flight1 or1 at any rate hold x 9 space1 assum+ t ! air %\ld be mov+ pa/ ! plane4 ,fig4 #fj4 ,horizontal & ,v]tical pull4 ,! table ( lift & drift gives a fairly accurate me?od ( det]m9+ ?is factor1 & we ref] to ! *apt] on t subject :i* w %[ ! mann] ( mak+ ! calculations4 ,,! ,,p[] ,,m\nt+4--,m "t & labor has be5 wa/$1 9 air%ip exp]im5ts1 9 poor motor m\nt+1 ?an 9 any o!r direction4 ,?is is especially true :]e two propell]s are us$1 or :]e ! con/ruction is su* t ! propell] is m\nt$ "s di/ance f ! motor4 ,,secur+ ,,! ,,propell] ,,to ,,! ,,%aft4--,b ev5 :]e ! propell] is m\nt$ on ! eng9e %aft1 too little c>e is ex]cis$ to fix x securely4 ,! vibratory "* ( ! m\nt+ makes ?is a matt] ( fir/ importance4 ,if !re is a solid base a poorly fix$ propell] w hold mu* long]1 b x is ! extreme vibration t causes ! propell] fa/5+ to give way4 ,,vibrations4--,if exp]im5t]s realiz$ t an insecure1 %ak+1 or weav+ b$ w\ld cause a loss ( f t5 to fifte5 p] c5t4 9 ! pull ( ! propell]1 m c>e & att5tion w\ld be giv5 to ?is "p ( ! /ructure4 ,,weaknesses ,,9 ,,m\nt+4--,! g5]al weaknesses to :i* att5tion %\ld be direct$ are1 fir/1 ! insecure atta*m5t ( ! propell] to ! %aft2 second1 ! liability ( ! base to weave2 or p]mit ( a torsional movem5t2 ?ird1 improp] brac+ ( ! base to ! ma9 body ( ! a]oplane4 ,if ! p[] is transf]r$ f ! cyl9d] to ! eng9e %aft :]e x c\ld deliv] its output )\t ! use ( a propell]1 x w\ld n be s important to consid] ! matt] ( vibration2 b ! propell]1 if p]mitt$ to vibrate1 or dance ab\t1 absorbs a va/ am\nt ( en]gy1 :ile at ! same "t cutt+ d[n its effective pull4 ,aside f ?is x is dang]\s to p]mit ! slighte/ displacem5t :ile ! eng9e is runn+4 ,any loos5ess is sure to gr[ worse1 in/ead ( bett]1 & _m accid5ts h be5 regi/]$ by bolts :i* h come loose f excessive vibration4 ,x is well1 !re=e1 to h ea* individual nut secur$1 or prop]ly lock$1 :i* is a matt] easily done1 & :5 s secur$ !re is b little tr\ble 9 go+ ov] ! ma*9e to notice j h[ mu* m ! nut mu/ be tak5 up to aga9 make x secure4 ,,! ,,gasol9e ,,tank4--,:at horrid details h be5 told ( ! pilots :o h be5 burn$ to dea? ) ! escap+ gasol9e aft] an accid5t1 be=e help arriv$4 ,!re is no excuse = su* dang]s4 ,mo/ ( su* accid5ts 7 due to ! old practice ( mak+ ! tanks ( exce$+ly light or ?9 mat]ial1 s t ! lea/ undue j> w\ld te> a hole at ! fa/5+ po9ts1 & ?us p]mit ! gasol9e to escape4 ,a ?ick copp] tank is by f> ! safe/1 z ?is metal w n readily rupture by ! wr5* :i* is likely 9 l&+4 ,,:]e ,,to ,,locate ,,! ,,tank4--,!re has be5 consid]able discussion z to ! prop] place to locate ! tank4 ,^? :o advocate its placem5t ov]head argue t 9 case ( an accid5t ! a]oplane is likely to ov]turn1 & ! tank w1 !re=e1 be bel[ ! pilot4 ,^? :o believe x %\ld be plac$ bel[1 claim t 9 case ( ov]turn+ x is saf] to h ! tank afire above ?an bel[4 ,,dang] ,,to ,,! ,,pilot4--,! great dang] to ! pilot1 9 all cases ( accid5ts1 lies 9 ! ov]turn+ ( ! ma*9e4 ,_m h _h accid5ts :]e ! ma*9e l&$ "r side up1 ev5 :]e ! fall 0 f a great height1 & ! only damage to ! aviator 0 bruises4 ,few1 if any1 pilots h escap$ :]e ! ma*9e has ov]turn$4 ,x is f> bett]1 9 case ! tank is light1 to h x deta*$ f its position1 :5 ! %ip /rikes ! e>?1 because 9 do+ s1 x w n be s likely to burn ! imprison$ aviator4 ,9 all cases ! tank %\ld be kept z f> away f ! eng9e z possible4 ,!re is no reason :y x _c be plac$ t[>d ! tail end ( ! ma*9e1 a place ( safety = two reasons3 ,fir/1 x is out ( ! rea* ( any possible dang] f fire2 &1 second1 ! accid5ts 9 ! pa/ %[ t ! tail frame is ! lea/ likely to be injur$4 ,9 look+ ov] ! illu/rations tak5 f ! accid5ts1 notice h[ few ( ! tails are ev5 dis>rang$1 & 9 _m ( !m1 :ile ! entire =e body & planes 7 cru%$ to atoms1 ! tail /ill rema9$ z a relic1 to %[ its comp>ative fre$om f ! accid5t4 ,9 all monoplanes ! tail really =ms "p ( ! support+ surface ( ! ma*9e1 & ! add+ ( ! weight ( ! gasol9e w\ld be plac+ b little additional duty on ! tail1 & x c\ld be readily provid$ = by a l>g] tail surface1 if requir$4 ,,! ,,clos$-,,9 ,,body4--,! clos$-9 body is a va/ improvem5t1 :i* has _h ! effect ( giv+ great] security to ! pilot1 b ev5 ?is is useless 9 case ( ov]turn+4 ,,/>t+ ,,! ,,ma*9e4--,! direction 9 :i* improvem5ts h be5 sl[ is 9 ! />t+ ( ! ma*9e4 ,! p[] is usually s m\nt$ t ! pilot has no control ov] ! />t+1 z he is n 9 a position to crank x4 ,! propell] be+ m\nt$ directly on ! %aft1 )\t ! int]v5tion ( a clut*1 makes x necess>y1 :ile on ! gr\nd1 = ! propell] to be />t$ by "s "o outside1 :ile o!rs hold ! ma*9e until x atta9s ! prop] spe$4 ,?is c\ld be readily rem$i$ by us+ a clut*1 b 9 ! pa/ ?is has be5 reg>d$ z "o ( ! weight luxuries t all h be5 try+ to avoid4 ,self />t]s are readily provid$1 & ?is ) ! provision t ! propell] c be ?r[n 9 or out at w1 w\ld be a va/ improvem5t 9 all ma*9es4 ,,propell]s ,,) ,,v>y+ ,,pit*4--,x is gr[+ m app>5t ea* day1 t a new type ( propell] mu/ be devis$ :i* w enable ! pilot to *ange ! pit*1 z ! spe$ increases1 & to give a great] pit*1 :5 alight+1 s z to make ! p[] output con=m to ! conditions4 ,su* propell]s1 :ile !y may be dang]\s1 & mu* heavi] ?an ! rigid type1 w1 no d\bt1 appe> 9 "t1 & ! real improvem5t w\ld be 9 ! direction ( hav+ ! blades capable ( automatic adju/m5t1 dep5d5t on ! w9d pressure1 or ! turn+ spe$1 & ?us n impose ?is additional duty on ! pilot4 ,,*apt] ,,xi ,,fly+ ,,ma*9e ,,accessories ,,! ,,anemomet]4--,x requires an exp]t to judge ! =ce or ! spe$ ( a w9d1 & ev5 !y w g a/ray 9 _! calculations4 ,x is an easy matt] to make a little app>atus :i* w accurately indicate ! spe$4 ,a device ( ?is k9d is call$ an ,anemomet]4 ,two o!r in/rum5ts h gr[n out ( ?is1 "o to indicate ! pressure1 & ! o!r ! direction ( ! mov+ air curr5t4 ,,! ,,anemograph4--,:ile ^! in/rum5ts indicate1 !y are also made s !y w record ! spe$1 ! pressure & ! direction1 & ! device = record+ ! spe$ & pressure is call$ a ,anemograph4 ,all ^! in/rum5ts may be atta*$ to ! same case1 & ?us make a h&y little device1 :i* w give all ! in=mation at a glance4 ,,! ,,anemometrograph4--,?is device = record+1 z well z indicat+ ! spe$1 pressure & direction1 is call$ an ,anemometrograph1 ,! two important p>ts ( ! comb9$ app>atus1 = ! spe$ & pressure1 are illu/rat$1 to %[ ! pr9ciple involv$4 ,:ile ! spe$ w give ! pressure1 x is necess>y to make a calculation to get ! result :ile ! ma*9e does ?is = y4 ,fig4 #fa4 ,spe$ ,indicator4 ,,! ,,spe$ ,,indicator4--,f\r hemisph]ical cups ,a are m\nt$ on f\r radiat+ arms ,b1 :i* are secur$ to a v]tical /em ,c1 & adapt$ to rotate 9 suitable be>+s 9 a case1 :i*1 = conv5i5ce 9 expla9+1 is n %[n4 ,on ! l[] end ( ! /em ,c1 is a small bevel p9ion1 :i* me%es ) a small] bevel p9ion )9 ! base4 ,?is latt] is on a %aft :i* c>ries a small ge> on its o!r end1 to me% ) a l>g] ge> on a %aft :i* c>ries a po9t] ,d t ?us turns at a greatly r$uc$ spe$1 s t x c be easily tim$4 ,fig4 #fb4 ,air ,pressure ,indicator4 ,,air ,,pressure ,,indicator4--,?is little app>atus is readily made ( a base ,a :i* is provid$ ) two uprights ,b1 ,c1 ?r\gh ! upp] ends ( :i* are holes to receive a horizontally-dispos$ b> ,d4 ,"o end ( ! b> is a flat plane surface ,e1 :i* is dispos$ at "r angles to ! b>1 & firmly fix$ !reto4 ,! o!r end ( ! b> has a lat]al p9 to s]ve z a pivot = ! end ( a l9k ,f1 its o!r end be+ h+$ to ! upp] end ( a lev] ,g1 :i* is pivot$ to ! po/ ,c1 a %ort di/ance bel[ ! h+$ atta*m5t ( ! l9k ,f1 s t ! long end ( ! po9t] :i* is con/itut$ by ! lev] ,g is bel[ its pivot1 & has1 !re=e1 a long range ( movem5t4 ,a spr+ ,i betwe5 ! upp] end ( ! po9t] ,g & ! o!r po/ ,b1 s]ves to hold ! po9t] at a z]o position4 ,a graduat$ scale plate ,j1 )9 range ( ! po9t] w %[ at a glance ! pressure 9 p\nds ( ! mov+ w9d1 & = ?is purpose x w\ld be conv5i5t to make ! plane ,e exactly "o foot squ>e4 ,,det]m9+ ,,! ,,pressure ,,f ,,! ,,spe$4-- ,^! two in/rum5ts c be made to *eck ea* o!r & ?us pretty accurately enable y to det]m9e ! prop] places to m>k ! pressure indicator1 z well z to make ! :eels 9 ! anemomet] ! prop] size to turn ! po9t] 9 seconds :5 ! w9d is bl[+ at a c]ta9 spe$1 say t5 miles p] h\r4 ,suppose ! air pressure indicator has ! scale divid$ into qu>t] p\nd m>ks4 ,?is w make x accurate en\gh = all purposes4 ,,calculat+ ,,pressures ,,f ,,spe$4--,! foll[+ table w give ! pressures f #e to #ajj miles p] h\r3 ,velocity ( w9d 9 ,pressure ,velocity ( w9d 9 ,pressure miles p] h\r p] sq4 ft4 miles p] h\r p] sq ft #e 4#aab #ee #ae4abe #aj 4#ejj #fj #ah4jjj #ae #a4abe #fe #ba4abe #bj #b4jjj #gj #bb4ejj #be #c4abe #ge #bh4abe #cj #d4fjj #hj #cb4jjj #ce #f4abf #hf #cf4abf #dj #h4jjj #ij #dj4ejj #de #aj4abe #ie #de4abe #ej #ab4e #ajj #ej4jjj ,,h[ ,,! ,,figures ,,are ,,det]m9$4--,! =ego+ figures are det]m9$ 9 ! foll[+ mann]3 ,z an example let u assume t ! velocity ( ! w9d is =ty-five miles p] h\r4 ,if ?is is squ>$1 or #de multipli$ by #de1 ! product is #bjbe4 ,9 _m calculations ! ma!matician employs :at is call$ a con/ant1 a figure t nev] v>ies1 & :i* is us$ to multiply or divide c]ta9 factors4 ,9 ?is case ! con/ant is #e_/ajjj1 or1 z usually writt51 4#jje4 ,?is is ! same z "o two hundr$?s ( ! squ>$ figure4 ,t w\ld make ! problem z foll[s3 #de ,x #de #bjbe _/ #bjj #aj4abe2 or1 #de ,x #de - #bjbe ,x 4#jje #aj4abe4 ,aga91 tw5ty-five miles p] h\r w\ld be #be ,x #be #fbe2 & ?is multipli$ by 4#jje equals #b p\nds pressure4 ,,conv]t+ ,,h\rs ,,into ,,m9utes4--,x is sometimes confus+ to ?9k ( miles p] h\r1 :5 y wi% to express x 9 m9utes or seconds4 ,a simple rule1 :i* is n absolutely accurate1 b is correct )9 a few feet1 9 ord] to express ! spe$ 9 feet p] m9ute1 is to multiply ! figure indicat+ ! miles p] h\r1 by #h #c_/d4 ,to illu/rate3 ,if ! w9d is mov+ at ! rate ( tw5ty miles an h\r1 x w travel 9 t "t #aje1fjj feet 7#ebhj ,x #bj74 ,z !re are sixty m9utes 9 an h\r1 #aje1fjj divid$ by #fj1 equals #agfj feet p] m9ute4 ,in/ead ( go+ ?r\gh all ?is process ( calculat+ ! spe$ p] m9ute1 rememb] to multiply ! spe$ 9 miles p] h\r by #ij1 :i* w give #ahjj feet4 ,?is is a little m !n two p] c5t4 above ! correct figure4 ,aga92 #dj ,x #ij equals #cfjj4 ,z ! correct figure is #cebj1 a little m5tal calculation w enable y to correct ! figures s z to get x )9 a few feet4 ,,*ang+ ,,spe$ ,,h\rs ,,to ,,seconds4--,z "o- sixtie? ( ! spe$ p] m9ute w repres5t ! rate ( movem5t p] second1 x is a comp>atively easy matt] to conv]t ! "t f spe$ 9 miles p] h\r to fraction ( a mile travel$ 9 a second1 by m]ely tak+ "o-half ( ! spe$ 9 miles1 & add+ x1 :i* w v ne>ly express ! true numb] ( feet4 ,z examples1 take ! foll[+3 ,if ! w9d is travel+ #bj miles an h\r1 x is easy to take "o-half ( #bj1 :i* is #aj1 & add x to #bj1 mak+ #cj1 z ! numb] ( feet p] second4 ,if ! w9d travels #ej miles p] h\r1 add #be1 mak+ #ge1 z ! spe$ p] second4 ,! correct spe$ p] second ( a w9d travel+ #bj miles an h\r is a little ov] #bi feet4 ,at #ej miles p] h\r1 ! correct figure is #gc #a_/c feet1 :i* %[ t ! figures "u ?is rule are )9 ab\t "o p] c5t4 ( be+ correct4 ,) ! table be=e y x w be an easy matt]1 by obs]v+ ! air pressure indicator1 to det]m9e ! prop] spe$ = ! anemomet]4 ,suppose x %[s a pressure ( two p\nds1 :i* w indicate a spe$ ( tw5ty miles an h\r4 ,y h ?us a fix$ po9t to />t f4 ,,pressure ,,z ,,! ,,squ>e ,,( ,,! ,,spe$4--,n[ x mu/ n be assum$ t if ! pressure at tw5ty miles an h\r is two p\nds1 t =ty miles an h\r x is f\r p\nds4 ,! pressure is z ! squ>e ( ! spe$4 ,?is may be expla9$ z foll[s3 ,z ! spe$ ( ! w9d increases1 x has a m effective pu% aga9/ an object ?an its rate ( spe$ indicates1 & ?is is mo/ simply express$ by say+ t ea* "t ! spe$ is d\bl$ ! pressure is f\r times great]4 ,z an example ( ?is1 let u take a spe$ ( t5 miles an h\r1 :i* means a pressure ( "o- half p\nd4 ,d\ble ?is spe$1 & we h #bj miles4 ,multiply+ "o-half p\nd by #d1 ! result is #b p\nds4 ,aga91 d\ble #bj1 :i* means #dj miles1 & multiply+ #b by #d1 ! result is #h4 ,d\bl+ =ty is eighty miles an h\r1 & aga9 multiply+ #h by #d1 we h #cb z ! p\nds pressure at a spe$ ( #hj miles an h\r4 ,! anemomet]1 h[ev]1 is con/ant 9 its spe$4 ,if ! po9t] %\ld turn once a second at #aj miles an h\r1 x w\ld turn twice at #bj miles an h\r1 & f\r times a second at #dj miles an h\r4 ,,gyroscopic ,,balance4--,"s advance has be5 made 9 ! use ( ! gyroscope = ! purpose ( giv+ lat]al /ability to an a]oplane4 ,:ile ! be/ ( su* devices is at be/ a make%ift1 x is well to und]/& ! pr9ciple on :i* !y op]ate1 & to get an und]/&+ h[ !y are appli$4 ,,! ,,pr9ciple ,,involv$4--,! only ?+ kn[n ab\t ! gyroscope is1 t x objects to *ang+ ! plane ( its rotation4 ,?is /atem5t mu/ be tak5 ) "s all[ance1 h[ev]1 z1 :5 left free to move1 x w *ange 9 "o direction4 ,to expla9 ?is )\t be+ too te*nical1 exam9e ,fig4 #fc1 :i* %[s a gyroscopic top1 "o end ( ! rim ,a1 :i* supports ! rotat+ :eel ,b1 hav+ a project+ f+] ,c1 t is m\nt$ on a p9-po9t on ! upp] end ( ! p$e/al ,d4 ,fig4 #fc4 ,! ,gyroscope4 ,:5 ! :eel ,b is set 9 rotation x w ma9ta9 itself s t its axis ,e is horizontal1 or at any o!r angle t ! top is plac$ 9 :5 ! :eel is spun4 ,if x is set s ! axis is horizontal ! :eel ,b w rotate on a v]tical plane1 & x =cibly objects to any attempt to make x turn except 9 ! direction indicat$ by ! curv$ arr[s ,f4 ,! :eel ,b w cause ! axis ,e to sw+ ar\nd on a horizontal plane1 & ?is turn+ movem5t is always 9 a c]ta9 direction 9 relation to ! turn ( ! :eel ,b1 & x is obvi\s1 !re=e1 t to make a gyroscope t w n move1 or sw+ ar\nd an axis1 ! plac+ ( two su* :eels side by side1 & rotat$ 9 opposite directions1 w ma9ta9 !m 9 a fix$ position2 ?is c also be accompli%$ by s m\nt+ ! two t "o rotates on a plane at "r angles to ! o!r4 ,fig4 #fd4 ,application ( ! ,gyroscope4 ,,! ,,application ,,( ,,! ,,gyroscope4--,)\t 9 any mann] %[+ ! /ructural details ( ! device1 9 its application to a fly+ ma*9e1 except 9 s f> z x may be necess>y to expla9 its op]ation1 we ref] to ,fig4 #fd1 :i* assumes t ,a repres5ts ! frame ( ! a]oplane1 & ,b a frame = hold+ ! gyroscopic :eel ,c1 ! latt] be+ m\nt$ s x rotates on a horizontal plane1 & ! frame ,b be+ h+$ =e & aft1 s t x is free to sw+ to ! "r or to ! left4 ,= conv5i5ce 9 expla9+ ! action1 ! planes ,e are plac$ at "r angles to _! regul> positions1 ,f be+ ! =w>d m>g9 ( ! plane1 & ,g ! re> edge4 ,wires ,h connect ! ends ( ! frame ,b ) ! respective planes1 or ail]ons1 ,e1 & ano!r wire ,i jo9s ! d[nw>dly-project+ arms ( ! two ail]ons1 s t motion is transmitt$ to bo? at ! same "t1 & by a positive motion 9 ei!r direction4 ,fig4 #fe4 ,action ( ! ,gyroscope4 ,9 ! second figure1 #fe1 ! frame ( ! a]oplane is %[n tilt$ at an angle1 s t its "r side is elevat$4 ,z ! gyroscopic :eel rema9s level x causes ! ail]on on ! "r side to *ange to a negative angle1 :ile at ! same "t giv+ a positive angle to ! ail]on on ! left side1 :i* w\ld1 z a result1 depress ! "r side1 & br+ ! frame ( ! ma*9e back to a horizontal position4 ,,=e ,,& ,,aft ,,gyroscopic ,,control4--,x is obvi\s t ! same application ( ?is =ce may be appli$ to control ! %ip =e & aft1 al?\gh x is d\btful :e!r su* a plan w\ld h any advantages1 s9ce ?is %\ld be :olly )9 ! control ( ! pilot4 ,lat]ally ! %ip %\ld n be out ( balance2 =e & aft ?is is a necessity1 & z ! great tr\ble ) all a]oplanes is to control !m lat]ally1 x may well be d\bt$ :e!r x w\ld add any?+ ( value to ! ma*9e by hav+ an automatic =e & aft control1 :i* might1 9 em]g5cies1 c\nt]act ! p]sonal control ( ! op]ator4 ,,angle ,,indicator4--,9 flight x is an exce$+ly difficult matt] = ! pilot to give an accurate idea ( ! angle ( ! planes4 ,if ! air is calm & he is mov+ ov] a c]ta9 c\rse1 & kn[s1 f exp]i5ce1 :at 8 spe$ is1 he may be able to judge ( ?is factor1 b he _c tell :at *anges take place "u c]ta9 conditions dur+ ! flight4 ,= ?is purpose a simple little indicator may be provid$1 %[n 9 ,fig4 #ff1 :i* is m]ely a v]tical bo>d ,a1 ) a p5dulum ,b1 sw++ =e & aft f a p9 a :i* projects out f ! bo>d a %ort di/ance above its c5t]4 ,! upp] end ( ! p5dulum has a he>t- %ap$ wire /ructure ,d1 t c>ries a slid+ weight ,e4 ,normally1 :5 ! a]oplane is on an ev5 keel1 or is ev5 at an angle1 ! weight ,e re/s )9 ! bottom ( ! loop ,d1 b %\ld !re be a sudd5 d[nw>d lur* or a quick upw>d incl9ation1 :i* w\ld cause ! p5dulum bel[ to rapidly sw+ 9 ei!r direction1 ! slid+ weight ,e w\ld at once move =w>d 9 ! same direction t ! p5dulum _h mov$1 & ?us c\nt]act1 = ! in/ant only1 ! sw+1 :5 x w\ld aga9 drop back into its c5tral position4 ,fig4 #ff4 ,angle ,indicator4 ,) su* an arrangem5t1 ! p5dulum w\ld hang v]tically at all times1 & ! po9t] bel[1 be+ 9 range ( a circle ) degrees indicat$ !reon1 & ! base atta*$ to ! frame ( ! ma*9e1 c always be obs]v$1 & ! conditions not$ at ! "t ! *anges take place4 ,,p5dulum ,,/abiliz]4--,9 _m respects ! use ( a p5dulum has advantages ov] ! gyroscope4 ,! latt] requires p[] to keep x 9 motion4 ,! p5dulum is always 9 condition = s]vice4 ,:ile x may be m difficult to adju/ ! p5dulum1 s t x does n affect ! planes by too rapid a sw+1 or an oscillation :i* is beyond ! true angle desir$1 /ill1 ^! are matt]s :i*1 9 "t1 w make ! p5dulum a /rong factor 9 lat]al /ability4 ,fig4 #fg4 ,simple ,p5dulum ,/abiliz]4 ,x is an exce$+ly simple matt] to atta* ! lead wires f an ail]on to ! p5dulum4 ,9 ,fig4 #fg "o plan is illu/rat$4 ,! p5dulum ,a sw+s f ! frame ,b ( ! ma*9e1 ! ail]ons a be+ 9 ?is case also %[n at "r angles to _! true positions4 ,! o!r1 ,fig4 #fh1 assumes t ! ma*9e is exactly horizontal1 & z ! p5dulum is 9 a v]tical position1 ! =w>d edges ( bo? ail]ons are elevat$1 b :5 ! p5dulum sw+s bo? ail]ons w be swung ) _! =w>d m>g9s up or d[n 9 unison1 & ?us ! prop] angles are made to "r ! ma*9e4 ,,/e]+ ,,& ,,controll+ ,,:eel4--,= ! purpose ( conc5trat+ ! control 9 a s+le :eel1 :i* has n alone a turn+ motion1 b is also m\nt$ 9 su* a mann] t x w oscillate to & fro1 is v desirable1 & is adapt$ = any k9d ( ma*9e4 ,fig4 #fh4 ,p5dulum ,/abiliz]s4 ,fig4 #fi %[s su* a /ructure1 9 :i* ,a repres5ts ! frame ( ! ma*9e1 & ,b a segm5t = ! /em ( ! :eel1 ! segm5t be+ made ( two p>ts1 s z to =m a guideway = ! /em a to travel betwe51 & ! segm5t is plac$ s t ! /em w travel 9 a =e & aft direction4 ,! l[] end ( ! /em is m\nt$ 9 a socket1 at ,d1 s t :ile x may be turn$1 x w also p]mit ?is oscillat+ motion4 ,ne> its l[] end is a cross b> ,e f :i* ! wires run to ! v]tical control plane1 & also to ! ail]ons1 if ! ma*9e is equipp$ ) !m1 or to ! w>p+ ends ( ! planes4 ,fig4 #fi4 ,/e]+ & ,control ,:eel4 ,above ! cross arms is a loose coll> ,f to :i* ! =e & aft cords are atta*$ t g to ! elevators1 or horizontal planes4 ,! upp] end ( ! /em has a :eel ,g1 :i* may also be equipp$ ) ! ?rottle & sp>k lev]s4 ,,automatic ,,/abiliz+ ,,w+s4--,unque/ionably1 ! be/ /abiliz] is "o :i* w act on its own initiative4 ,! difficulty ) automatic devices is1 t !y act too late1 z a g5]al ?+1 to be effective4 ,! device repres5t$ 9 ,fig4 #gj is v simple1 & 9 practice is f\nd to be mo/ effici5t4 ,9 ?is ,fig4 #gj ,a & ,b repres5t ! upp] & ! l[] planes1 respectively4 ,ne> ! end v]tical /&>ds a1 ,d1 are n>r[ w+s ,e ,e1 ,f ,f1 h+$ on a =e & aft l9e close bel[ ea* ( ! planes1 ! w+s be+ at su* di/ances f ! /&>ds ,c ,d t :5 !y sw+ outw>dly !y w t\* ! /&>ds1 & :5 9 t position w be at an angle ( ab\t #ce degrees f ! planes ,a ,b4 ,fig4 #gj4 ,automatic ,/abiliz+ ,w+s4 ,fig4 #ga4 ,action ( ,/abiliz+ ,w+s4 ,inw>dly !y are p]mitt$ to sw+ up & lie p>allel ) ! planes1 z %[n 9 ,fig4 #ga :]e ! planes are at an angle4 ,9 turn+1 all ma*9es skid1--t is !y travel obliquely across ! field1 & ?is is also true :5 ! %ip is sail+ at "r angles to ! c\rse ( ! w9d4 ,?is w be made cle> by ref]5ce to ,fig4 #gb1 9 :i* ! d>t ,a repres5ts ! direction ( ! movem5t ( ! a]oplane1 & ,b ! direction ( ! w9d1 ! v]tical rudd] a be+ almo/ at "r angles to ! c\rse ( ! w9d4 ,fig4 #gb4 ,into ! ,w9d at an ,angle4 ,9 turn+ a circle ! same ?+ takes place z %[n 9 ,fig4 #gc1 ) ! tail at a diff]5t angle1 s z to give a turn+ movem5t to ! plane4 ,x w be se5 t 9 ! circl+ movem5t ! t5d5cy ( ! a]oplane is to fly out at a tang5t1 %[n by ! l9e ,d1 s t ! planes ( ! ma*9e are n radially-dispos$ ) ref]5ce to ! c5t] ( ! circle1 ! l9e ,e %[+ ! true radial l9e4 ,ref]r+ n[ to ,fig4 #ga1 x w be se5 t ?is skidd+ motion ( ! ma*9e sw+s ! w+s ,e ,f inw>dly1 s t !y (f] no resi/ance to ! oblique movem5t1 b ! w+s ,e ,e1 at ! o!r end ( ! planes are swung outw>dly1 to provide an angle1 :i* t5ds to raise up ! inn] end ( ! planes1 & !reby seek to keep ! planes horizontal4 ,fig4 #gc4 ,turn+ a ,circle4 ,,b>omet]s4--,^! in/rum5ts are us$ = regi/]+ heights4 ,a b>omet] is a device = measur+ ! weight or pressure ( ! air4 ,! air is suppos$ to ext5d to a height ( #dj miles f ! surface ( ! sea4 ,a column ( air "o in* squ>e1 & =ty miles high1 weighs ! same z a column ( m]cury "o in* squ>e & #cj in*es high4 ,su* a column ( air1 or ( m]cury1 weighs #ad #c_/d p\nds4 ,if ! air column %\ld be weigh$ at ! top ( ! m\nta91 t "p above w\ld weigh less ?an if measur$ at ! sea level1 h5ce1 z we asc5d or desc5d ! pressure becomes less or m1 dep5d5t on ! altitude4 ,m]cury is also us$ to indicate temp]ature1 b ?is is br\ght ab\t by ! expansive quality ( ! m]cury1 & n by its weight4 ,fig4 #gd4 ,an]oid ,b>omet]4 ,,an]oid ,,b>omet]4--,! t]m ,an]oid b>omet] is frequ5tly us$ 9 connection ) air- %ip exp]im5ts4 ,! ^w an]oid means n wet1 or n a fluid1 l m]cury1 s t1 :ile an]oid b>omet]s are be+ made :i* d use m]cury1 !y are g5]ally made )\t4 ,"o su* =m is illu/rat$ 9 ,fig4 #gd1 :i* repres5ts a cyl9drical %ell ,a1 :i* has at ea* end a head ( conc5trically =m$ corrugations4 ,^! heads are securely fix$ to ! ends ( ! %ell ,a4 ,)91 "o ( ! disk heads has a %ort /em ,c1 :i* is atta*$ to ! %ort end ( a lev] ,d1 ?is lev] be+ pivot$ at ,e4 ,! out] end ( ?is lev] is h+$ to ! %ort end ( ano!r lev] ,f1 & s by comp\nd+ ! lev]s1 x w be se5 t a v slight movem5t ( ! head ,b w cause a consid]able movem5t 9 ! long end ( ! lev] ,f4 ,?is end ( ! lev] ,f connects ) "o limb ( a bell-crank lev] ,g1 & its o!r limb has a too!d rack connection ) a ge> ,h1 :i* turns ! %aft to :i* ! po9t] ,i is atta*$4 ,air is )drawn f ! int]ior ( ! %ell1 s t any *ange 9 ! pressure1 or weight ( ! atmosph]e1 is at once felt by ! disk heads1 & ! f+] turns to indicate ! am\nt ( pressure4 ,,hydroplanes4--,hydro means wat]1 h5ce ! t]m hydroplane has be5 giv5 to ma*9es :i* h suitable pontoons or boats1 s !y may alight or initiate flight f wat]4 ,!re is no p>ticul> =m :i* has be5 adopt$ to atta* to a]oplanes1 ! object g5]ally be+ to s make !m t !y w su/a9 ! greate/ am\nt ( weight ) ! lea/ subm]g5ce1 & also (f] ! lea/ resi/ance :ile ! motor is draw+ ! ma*9e along ! surface ( ! wat]1 prep>atory to laun*+ x4 ,,su/a9+ ,,weight ,,( ,,pontoons4--,a pontoon hav+ )9 no?+ b air1 is m]ely a measur+ device :i* det]m9es ! diff]5ce betwe5 ! weight ( wat] & ! am\nt plac$ on ! pontoon4 ,wat] weighs #fb #a_/b p\nds p] cubic foot4 ,ord9>y wood1 an av]age ( #cb p\nds1 & /eel #ejj p\nds4 ,x is1 !re=e1 an easy matt] to det]m9e h[ mu* ( solid matt] w be su/a9$ by a pontoon ( a giv5 size1 or :at ! dim5sions ( a pontoon %\ld be to hold up an a]oplane :i* weighs1 ) ! pilot1 say1 #aajj p\nds4 ,z we mu/ calculate = a suffici5t excess to prev5t ! pontoons f be+ too mu* imm]s$1 & also all[ a suffici5t diff]5ce 9 weight s t !y w keep on ! surface :5 ! a]oplane /rikes ! surface 9 alight+1 we w take ! figure ( #aejj p\nds to make ! calculations f4 ,if ?is figure is divid$ by #fb #a_/b we %all f9d ! cubical cont5ts ( ! pontoons1 n consid]+1 ( c\rse1 ! weight ( ! mat]ial ( :i* !y are compos$4 ,?is calculation %[s t we mu/ h #bd cubic feet 9 ! pontoons4 ,z !re %\ld be two ma9 pontoons1 & a small] "o = ! re>1 ea* ( ! ma9 ones might h t5 cubic feet1 & ! small] "o f\r cubic feet4 ,,%apes ,,( ,,! ,,pontoons4--,we are n[ ready to design ! %apes4 ,fig4 #ge %[s ?ree g5]al types1 ,a be+ made rectangul> 9 =m1 ) a tap]+ =w>d end1 s con/ruct$ z to ride up on ! wat]4 ,! type ,b has a r\nd$ "u body1 ! =w>d end be+ also skiff-%ap$ to decrease z mu* z possible ! resi/ance ( ! wat] impact4 ,fig4 #ge4 ,hydroplane ,floats4 ,! ?ird type ,c is made 9 ! =m ( a clos$ boat1 ) bo? ends po9t$1 & ! bottom r\nd$1 or provid$ ) a keel4 ,or1 z 9 "s cases ! body may be made triangul> 9 cross section s t z x is subm]g$ its su/a9+ weight w increase at a great] degree z x is press$ d[n ?an its v]tical measurem5t indicates4 ,all ?is1 h[ev]1 is a matt] left to ! judgm5t ( ! design]1 & is1 9 a great degree1 dep5d5t on ! "* ( ! craft to :i* x is to be appli$4 ,,*apt] ,,xii ,,exp]im5tal ,,"w ,,9 ,,fly+ ,,! novice ab\t to take 8 fir/ trial trip 9 an automobile w soon le>n t ! great task 9 8 m9d is to prop]ly />t ! ma*9e4 ,he is consci\s ( "o ?+1 t x w be an easy matt] to /op x by cutt+ (f ! fuel supply & apply+ ! brakes4 ,,c]ta9 ,,conditions ,,9 ,,fly+4--,9 an a]oplane conditions are rev]s$4 ,%utt+ (f ! fuel supply & apply+ ! brakes only br+ on ! ma9 difficulty4 ,he mu/ le>n to /op ! ma*9e aft] all ?is is done1 & ?is is ! great te/ ( fly+4 ,x is n ! laun*+1-- ! ability to get into ! air1 b ! l&+1 t gives ! pupil 8 fir/ %ock4 ,man is s accu/om$ to ! little swirls ( air all ab\t him1 t he does n appreciate :at !y mean to a ma*9e :i* is once free to glide along 9 ! little curr5ts :i* are s unnoticeable to him z a p$e/rian4 ,! cont\r ( ! e>?1 ! f5ces1 trees1 little elevations & o!r natural surr\nd+s1 all h _! effect on a slight mov+ air curr5t1 & ^! inequalities affect ! air & di/urb x to a /ill great] ext5t z ! w9d increases4 ,ev5 9 a /ill air1 ) ! sun %9+1 !re are air eddies1 caus$ by ! unev5 heat+ ( ! air 9 space4 ,,heat ,,9 ,,air4--,heat is transmitt$ ?r\gh ! air by :at is call$ convection1 t is1 ! p>ticles ( ! air transmit x f "o po9t to ! next4 ,if a room is clos$ up tight1 & a little ap]ture provid$ s z to let 9 a /reak ( sunlight1 x w give "s idea ( ! unre/ ( ! atmosph]e4 ,?is may be exhibit$ by smoke along ! l9e ( ! sun's rays1 :i* indicates t ! p>ticles ( air are con/antly 9 motion1 al?\gh !re may be absolutely no?+ 9 ! room to di/urb x4 ,,motion ,,:5 ,,9 ,,flight4--,if y c imag9e a small air%ip float+ 9 t space1 y c readily conceive t x w be hurl$ hi!r & ?i!r by ! motion :i* is ?us app>5t to ! eye4 ,?is motion is greatly acc5tuat$ by ! surface ( ! e>?1 indep5d5tly ( its unev5 cont\r4 ,if a ball is ?r[n ?r\gh ! air1 its dynamic =ce is measur$ by its impact4 ,s ) light1 & heat4 ,9 ! space betwe5 ! planets x is v cold4 ,! sunlight1 or ! rays f ! sun are !re1 j ! same z on ! e>?4 ,unless ! rays come into contact ) some?+1 !y produce no effect4 ,:5 ! beams f ! sun come into contact ) ! atmosph]e a dynamic =ce is ex]t$1 j ! same z :5 ! ball /ruck an object4 ,:5 ! rays rea* ! e>?1 reflection takes place1 & ^! reflect$ beams act on ! air "u diff]5t conditions4 ,,*ang+ ,,atmosph]e4--,if ! air is full ( moi/ure1 z x may be at "s places1 :ile comp>atively dry at o!r po9ts1 ! reflection ?r\gh\t ! moi/ area is mu* great] ?an 9 ! dry places1 h5ce evaporation w take place & :5ev] a liquid vaporizes x means heat4 ,on ! o!r h&1 :5 ! vapor is turn+ to a liquid1 cond5sation takes place1 & t means cool+4 ,if ! air %\ld be ( ! same degree ( saturation ?r\gh\t1--t is1 h ! same am\nt ( moi/ure ev]y:]e1 !re w\ld be few w9ds4 ,^! rem>ks apply to conditions :i* exi/ ov] l[ altitudes all ov] ! e>?4 ,b at high altitudes ! conditions are entirely diff]5t4 ,z we asc5d ! air becomes r>]4 ,x has less moi/ure1 because a wet atmosph]e1 be+ heavi]1 lies ne>] ! surface ( ! e>?4 ,be+ r>] ! action ( sunlight on ! p>ticles is less int5se4 ,reflection & refraction ( ! rays act+ on ! light atmosph]e d n produce su* a p[]ful effect z on ! air ne> ! gr\nd4 ,all ^! conditions--! cont\r ( ! e>?2 ! unev5 "* ( ! moi/ure 9 ! air2 ! inequalities ( ! convection curr5ts2 & ! un/able1 t5u\s1 ela/ic nature ( ! atmosph]e1 make ! trials ( ! aviator a haz>d\s "o1 & x has br\ght out num]\s !ories connect$ ) bird flight4 ,"o ( ^! assumes t ! bird1 by means ( its f9ely organiz$ s5se1 is able to detect ris+ air curr5ts1 & x selects !m 9 its flight1 & by t means is enabl$ to cont9ue 9 flight indef9itely1 by so>+1 or by flapp+ its w+s4 ,,asc5d+ ,,curr5ts4--,x has n be5 expla9$ h[ x happ5s t ^! p>ticul> asc5d+ curr5ts always appe> directly 9 ! l9e ( ! bird flight2 or :y x is t :51 = in/ance1 a flock ( wild geese :i* always fly ?r\gh space 9 an ,a-%ap$ =mation1 are able to get asc5d+ air curr5ts ov] ! wide scope ( space !y cov]4 ,,aspirate ,,curr5ts4--,"s ye>s ago1 9 mak+ exp]im5ts ) ! out/ret*$ w+s ( "o ( ! l>ge so>+ birds1 a ,fr5* sailor 0 surpris$ to exp]i5ce a peculi> pull+ motion1 :5 ! bird's w+s 7 held at a c]ta9 angle1 s t ! air actually seem$ to draw x into ! tee? ( ! curr5t4 ,x is kn[n t if a ball is susp5d$ by a /r+1 & a jet ( air is direct$ aga9/ x1 9 a p>ticul> way1 ! ball w move t[>d ! jet1 in/ead ( be+ driv5 away f x4 ,a well kn[n spray+ device1 call$ ! ball nozzle1 is simply a ball on ! end ( a nozzle1 & ! /ream ( wat] issu+ is n effectual to drive ! ball away4 ,f ! bird incid5t allud$ to1 a new !ory 0 prop\nd$1 namely1 t birds flew because ( ! aspirat$ action ( ! air1 & ! w+s & body 7 s made z to cause ! mov+ air curr5t to act on x1 & draw x =w>dly4 ,,out/ret*$ ,,w+s4--,?is only add$ to ! bird w+ !ory a new argum5t t all fly+ ?+s mu/ h out/ret*$ w+s1 9 ord] to fly1 =gett+ t ! ball1 :i* has no out/ret*$ w+s1 has also ! same aspirate movem5t attribut$ to ! w+s ( ! bird4 ,! =ego+ rem>ks are made 9 ord] to impress on ! novice t !ories d n make fly+ ma*9es1 & t speculations1 or analogies ( :at we see all ab\t u1 w n make an aviator4 ,a fly+ ma*9e is a "q ( dynamics1 j z surely z ! action ( ! sun on ! air1 & ! movem5ts ( ! curr5ts1 & ! k ( apply+ ^? =ces 9 ! fly+ ma*9e makes ! aviator4 ,,! ,,/>t+ ,,po9t4--,be=e ! un9itiat$ %\ld attempt to ev5 m\nt a ma*9e he %\ld "k :at x is compos$ (1 & h[ x is made4 ,8 inve/igation %\ld take 9 e "p ( ! me*anism2 he %\ld und]/& ab\t ! plane surface1 :at ! /resses are ^u its surface1 :at is ! duty ( ea* /rut1 or brace or wire & be able to make ! prop] repairs4 ,,! ,,vital ,,"p ,,( ,,! ,,ma*9e4--,! motor1 ! life ( ! ma*9e itself1 %\ld be l a book to him4 ,x is n requir$ t he %\ld "k all ! !ories :i* is necess>y 9 ! build+1 z to ! _m features :i* g to make up a sci5tifically-design$ motor2 b he mu/ "k h[ & :y x works4 ,he %\ld und]/& ! cam action1 :]eby ! valves are lift$ at ! prop] "t2 :at ! effect ( ! sp>k advance means2 ! ?rottl+ ( ! eng9e2 air admission & supply2 ! regulation ( ! c>buret]2 its me*anism & con/ruction2 ! propell] %\ld be /udi$1 & its action at v>i\s spe$s4 ,,/udy+ ,,! ,,action ,,( ,,! ,,ma*9e4--,!n comes ! /udy on ! seat ( ! ma*9e itself4 ,x w be a novel s5sation4 ,be=e him is ! /e]+ :eel1 if x %\ld be s equipp$4 ,turn+ x to ! "r1 sw+s ! v]tical tail plane s ! ma*9e w turn to ! "r4 ,c]ta9ly1 he kn[s t2 b h[ f> mu/ he turn ! :eel to give x a c]ta9 angle4 ,x is n en\gh to "k t a lev] or a :eel :5 mov$ a c]ta9 way w move a plane a def9ite direction4 ,he %\ld le>n to "k in/9ctively1 h[ ,,f> a movem5t to make to get a c]ta9 result 9 ! plane itself1 & "u runn+ conditions1 z well4 ,suppose we h an automobile1 runn+ at ! rate ( t5 miles an h\r1 & ! *auffeur turns ! /e]+ :eel t5 degrees4 ,he c d s ) p]fect safety2 b let ! ma*9e be go+ =ty miles an h\r1 & turn ! :eel t5 degrees1 & x may mean an accid5t4 ,9 "o case ! ma*9e is mov+ #ad #a_/b feet a second1 & 9 ! o!r in/ance #eh feet4 ,if ! air%ip has a lev] = controll+ ! angle ( flight1 he mu/ /udy its arrangem5t1 & note h[ f> x mu/ be mov$ to assume ! prop] elevat+ angle4 ,!n come ! means = controll+ ! lat]al /ability ( ! ma*9e4 ,all ^! features %\ld be consid]$ & /udi$ ov] & ov]1 until y h made !m y\r fri5ds4 ,:ile ?us engag$1 y are p]fectly sure t y c rememb] & act on a set ( complicat$ movem5ts4 ,y imag9e t y are skimm+ ov] ! gr\nd1 & y\r s5se tells y t y h suffici5t spe$ to effect a laun*+4 ,9 y\r m9d ! critical "t has come4 ,,elevat+ ,,! ,,ma*9e4--,simply give ! elevator lev] ! prop] angle1 %>p & quick & up y g4 ,z ! ma*9e responds1 & y c feel ! cu%ion+ motion1 :i* foll[s1 z x beg9s to ride ! air1 y are aw>e ( a s5sation z ?\gh ! ma*9e 7 ab\t to turn ov] to "o side2 y ?9k ( ! lat]al control at once1 b 9 do+ s =get t ! elevator mu/ be *ang$1 or y w g too high4 ,y =get ab\t ! e>?2 y are too busy ?9k+ ab\t sev]al ?+s :i* seem to ne$ y\r att5tion4 ,yes1 !re are a v>iety ( matt]s :i* w cr[d ^u y1 ea* ( :i* require two ?+s2 ! fir/ be+ to get ! prop] lev]1 & ! second1 to move x j s f>4 ,9 ! e>ly days ( a]oplan+1 :5 accid5ts came ?ick & fa/1 ! mo/ usual explanation :i* came f ! pilot1 :5 he recov]$1 03 ,i pu%$ ! lev] too f>4 ,hundr$s ( trial ma*9es 7 built1 :5 man le>n$ t he c\ld fly1 & 9 e in/ance1 x is safe to say1 ! exp]im5t] made ! mo/ /r5u\s ex]tion to get up 9 ! air ! fir/ "t ! ma*9e 0 put on ! trial gr\nd4 ,x is a wond] t accid5ts 7 n record$ by ! hundr$s1 in/ead ( by ! comp>atively few t 7 he>d f4 ,x 0 v disc\rag+1 no d\bt1 t ! ma*9es w\ld n fly1 b t all ( !m1 if !y _h suffici5t p[]1 w\ld fly1 !re c be no d\bt4 ,,h[ ,,to ,,practice4--,absolute famili>ity ) e "p ( ! ma*9e & conditions is ! fir/ ?+4 ,! ma*9e is br\ght out1 & ! eng9e te/$1 ! ma*9e be+ held 9 lea% :ile ?is is done4 ,x is !n ?rottl$ d[n s t ! p[] ( ! eng9e w be less ?an is necess>y to raise ! ma*9e f ! gr\nd4 ,,! ,,fir/ ,,/age4--,usually x w require ov] #be miles an h\r to raise ! ma*9e4 ,! eng9e is set 9 motion1 & n[1 = ! fir/ "t a new s5sation takes possession ( y1 = ! reason t y are cut (f f communication ) ^? ar\nd y z absolutely z ?\gh !y 7 a hundr$ miles away4 ,?is new dep5d5ce on y\rself is1 9 itself1 "o ( ! be/ tea*]s y c\ld h1 because x beg9s to in/ill confid5ce & control4 ,z ! ma*9e d>ts =w>d1 go+ t5 or fifte5 miles an h\r1 ) ! d9 ( ! eng9e beh9d y1 & feel+ ! rumbl+ motion ( ! :eels ov] ! unev5 surface ( ! e>?1 y h ! s5sation ( go+ =ty miles an h\r4 ,! newness ( ! fir/ s5sation1 :i* is always "u ^? conditions v mu* augm5t$ 9 ! m9d1 we>s away z ! ma*9e goes back & =?4 ,!re is only "o control t requires y\r c>e1 namely1 to keep x on a /raight c\rse4 ,?is is easy "w1 b y are le>n+ to make y\r control a reflex action1--to d x )\t ex]cis+ a di/9ct w p[]4 ,,pati5ce ,,! ,,mo/ ,,difficult ,,?+4--,if y h ! pati5ce1 z y %\ld1 to cont9ue ?is runn+ practice1 until y absolutely elim9ate ! "r & left control1 z a matt] ( ?\ght1 occasionally1 if ! air is /ill turn+ ! ma*9e1 & ev5tually1 br++ x back1 by turn+ x completely ar\nd1 :ile skimm+ ! gr\nd1 y w be ready = ! second /age 9 ! trials4 ,,! ,,second ,,/age4--,! eng9e is n[ arrang$ s t x w b>ely lift1 :5 runn+ at its be/4 ,aft] ! eng9e is at full spe$1 & y are sure ! ma*9e is go+ fa/ en\gh1 ! elevator control is turn$ to po9t ! ma*9e 9 ! air4 ,x is a t5se mom5t4 ,y are on ! al]t4 ,! elevator is turn$1 & ! =w>d end *anges its relation ) ! gr\nd be=e y4 ,!re 0 a slight lift1 b y\r caution induces y to return ! planes to _! normal runn+ angle4 ,y try x aga94 ,y are n[ c]ta9 t ! ma*9e made a leap & left ! gr\nd4 ,?is is ! exhil>at+ mom5t4 ,) a calm air ! ma*9e is turn$ :ile runn+1 by means ( ! v]tical rudd]s4 ,?is is an easy matt]1 because :ile go+ at tw5ty miles an h\r1 ! weight ( ! ma*9e on ! surface ( ! gr\nd is less ?an "o-t5? ( its weight :5 at re/4 ,?us ! trial sp9s1 half ! "t 9 ! air1 9 little glides ( fifty to a hundr$ feet1 increas+ 9 l5g?1 give practice1 practice1 ,,practice1 ea* turn ( ! field mak+ ! sport less excit+ & fix+ ! controls m p]fectly 9 ! m9d4 ,,! ,,?ird ,,/age4--,?us f> y h be5 turn+ on ! gr\nd4 ,y want to turn 9 ! air4 ,only ! tail control 0 requir$ :ile on ! gr\nd4 ,n[ two ?+s are requir$ aft] y leave ! gr\nd 9 try+ to make a turn3 namely1 putt+ ! tail at ! prop] angle1 & tak+ *>ge ( ! /abiliz]s1 because 9 mak+ ! turn 9 ! air1 ! fir/ ?+ :i* w arre/ ! att5tion w be ! t5d5cy ( ! ma*9e to turn ov] 9 ! direction t y are turn+4 ,aft] go+ back & =? 9 /raight-away glides1 until y h p]fect confid5ce & full control1 comes ! p]iod :5 ! turns %\ld be practic$ on4 ,^! %\ld be long1 & tri$ only on t portion ( ! field :]e y h pl5ty ( room4 ,,obs]vations ,,:ile ,,9 ,,flight4--,if !re are any bad spots1 or trees1 or dang]\s places1 !y %\ld be spott$ out1 & m5tally not$ be=e attempt+ to make any flight4 ,:5 9 ! air dur+ ^! trials y w h en\gh to occupy y\r m9d )\t look+ out = ! haz>d\s regions at ! same "t4 ,make ! fir/ turns 9 a /ill air4 ,if y %\ld attempt to make ! fir/ attempts ) a w9d bl[+ y w f9d a comp\nd motion t w v likely give y a surprise4 ,9 mak+ ! fir/ turn y w get ! s5sation ( try+ to fly aga9/ a w9d4 ,assum+ t y are turn+ to ! left1 x w h ! s5sation ( a w9d com+ to y f ! "r4 ,,fly+ ,,9 ,a ,,w9d4--,suppose y are fly+ directly 9 ! face ( a w9d1 ! mom5t y beg9 to turn ! action1 or bite ( ! w9d1 w cause ! ends ( ! planes to ! "r to be unduly elevat$1 mu* m s ?an if ! air %\ld be calm4 ,?is rais+ action w be liable to />tle y1 because up to ?is "t y h be5 accu/om$ to fly+ along 9 a /raight l9e4 ,:ile fly+ ar\nd at ! "p ( ! circle :]e ! w9d /rikes y directly on ! "r side ! ma*9e has a t5d5cy to climb1 & y try to depress ! =w>d end1 b z soon z y rea* t "p ( ! circle :]e ! w9ds beg9 to /rike on y\r back1 an entirely new ?+ occurs4 ,z ! ma*9e is n[ travel+ ) ! w9d1 its grip on ! air is less1 & s9ce ! planes 7 set to l[] ! ma*9e1 at ! fir/ "p ( ! turn1 ! desc5t w be pretty rapid unless ! angle is correct$4 ,,fir/ ,,trials ,,9 ,,quiet ,,atmosph]e4--,all ?is w\ld be avoid$ if ! fir/ trials 7 made 9 a quiet atmosph]e4 ,fur!rmore1 y w be told t 9 mak+ a turn ! ma*9e %\ld be po9t$ d[nw>dly1 z ?\gh ab\t to make a glide4 ,?is c be done ) safety1 9 a /ill air1 al?\gh y may be fly+ l[1 b x w\ld be exce$+ly dang]\s ) a w9d bl[+4 ,,mak+ ,,turns4--,:5 mak+ a turn1 "u no circum/ances try to make a l&+4 ,?is %\ld nev] be done except :5 fly+ /raight1 & !n safety dem&s t ! l&+ %\ld be made aga9/ ! w9d & n ) x4 ,!re are two reasons = ?is3 ,fir/1 :5 fly+ ) ! w9d ! spe$ mu/ be great] ?an :5 fly+ aga9/ x4 ,by great] spe$ is meant relative to ! e>?4 ,if ! ma*9e has a spe$ ( ?irty miles an h\r1 9 /ill air1 ! spe$ w\ld be =ty miles an h\r go+ ) ! w9d1 b only tw5ty miles aga9/ ! w9d4 ,second1 ! bank+ ( ! planes aga9/ ! air is m effective :5 go+ into ! w9d ?an :5 travel+ ) x1 &1 !re=e1 ! spe$ at :i* y contact ) ! e>? is less5$ to su* an ext5t t a comp>atively easy l&+ is effect$4 ,,! ,,f\r? ,,/age4--,aft] suffici5t "t has be5 devot$ to ! long turns %ort] turns may be made1 & ^! also require ! same c>e1 & w give an opportunity to use ! lat]al controls to a great] ext5t4 ,beg9 ! turns1 n by an abrupt ?r[ ( ! turn+ rudd]1 b br+ x ar\nd g5tly1 correct+ ! turn+ movem5t to a /raight c\rse1 if y f9d ! ma*9e incl9$ to tilt too mu*1 until y get us$ to ! s5sation ( keel+ ov]4 ,con/ant practice at ?is w soon give confid5ce1 & assure y t y h full control ( ! ma*9e4 ,,! ,,figure #h4--,y are n[ to increase ! height ( fly+1 & ?is involves also ! ability to turn 9 ! opposite direction1 s t y may be able to exp]i5ce ! s5sation ( us+ ! /abiliz]s 9 ! opposite direction4 ,y w f9d 9 ?is practice t ! s5ses mu/ take 9 ! c\rse ( ! w9d f two qu>t]s n[1 z y attempt to describe ! figure #h4 ,?is is a te/ :i* is requir$ 9 ord] to obta9 a pilot's lic5se4 ,x means t y %all be able to %[ ! ability to turn 9 ei!r direction ) equal facility4 ,to keep an ev5 fly+ altitude :ile describ+ ?is figure 9 a w9d1 is ! sev]e/ te/ t c be exact$4 ,,! ,,volplane4--,?is is ! te*nical t]m = a glide4 ,_m accid5ts h be5 record$ ow+ to ! /opp+ ( ! motor1 :i* 9 ! pa/ might h be5 avoid$ if ! "* ( ! glide _h be5 und]/ood4 ,! only ?+ t n[ tr\bles ! pilot :5 ! eng9e goes dead1 is to select a l&+ place4 ,! prop] c\rse 9 su* a case is to urge ! ma*9e to desc5d z rapidly z possible1 9 ord] to get a headway1 = ! "t be+4 ,z !re is n[ no propell+ =ce ! glide is dep5d$ ^u to act z a sub/itute4 ,! exp]i5c$ pilot w n make a /raight-away glide1 b l ! vulture1 or ! condor1 & birds ( t class1 so> 9 a circle1 & ?us1 by pass+ ov] & ov] ! same surfaces ( ! e>?1 enable him to select a prop] l&+ place4 ,,! ,,l&+4--,! pilot :o c make a good l&+ is g5]ally a good fly]4 ,x requires nicety ( judgm5t to come d[n prop]ly4 ,"o ?+ :i* w appe> novel aft] ! fir/ altitude flights are attempt$ is ! peculi> s5sation ( ! app>5tly increas$ spe$ z ! e>? comes close up to ! ma*9e4 ,at a height ( "o hundr$ feet1 fly+ ?irty miles an h\r1 does n seem fa/1 because ! surface ( ! e>? is su* a di/ance away t p>ticul> objects rema9 9 view = "s mom5ts2 b :5 )9 t5 feet ( ! surface ! same object is 9 ! eye = an in/ant only4 ,?is l5ds a sort ( t]ror to ! novice4 ,he imag9es a great _m ?+s1 b =gets "s ?+s :i* are v important to d at ?is "t4 ,"o is1 t ! front ( ! ma*9e mu/ be ?r[n up s z to bank ! planes aga9/ ! w9d4 ,! next is to %ut (f ! p[]1 :i* is to be done ! mom5t ! :eels /rike ! gr\nd1 or a little be=e4 ,^u 8 judgm5t ( ! "t ( fir/ t\*+ ! e>? dep5ds ! success ( safely alight+4 ,he may bank too high1 & come d[n on ! tail ) disa/r\s results4 ,if !re is pl5ty ( field room x is bett] to come d[n at a less angle1 or ev5 keep ! ma*9e at an ev5 keel1 & ! elevator c !n depress ! tail :ile runn+ ov] ! gr\nd1 & ?us br+ ! ma*9e to re/4 ,frequ5tly1 :5 ab\t to l& ! ma*9e w rock f side to side4 ,9 su* a case x is f> saf] to g up into ! air ?an to make ! l&1 because1 unless ! utmo/ c>e is ex]cis$1 "o ( ! w+ tips w /rike ! e>? & wreck ! ma*9e4 ,ano!r dang] po9t is los+ headway1 z ! e>? is ne>$1 due to fly+ at too flat an angle1 or aga9/ a w9d t happ5s to be bl[+ p>ticul>ly h>d at ! l&+ place4 ,if ! motor is /ill go+ ?is does n make s mu* diff]5ce1 b 9 a volplane x means t ! desc5t mu/ be s /eep1 at ! la/ mom5t ( flight1 t ! *assis is liable to be cru%$ by ! impact4 ,,fly+ ,,altitude4--,x is d\btful :e!r ! di/urb$ condition ( ! atmosph]e1 due to ! cont\r ( ! e>?'s surface1 rea*es high] ?an #ejj feet4 ,ov] a level area x is c]ta9 t x is mu* less1 b 9 "s sections ( ! c\ntry1 :]e ! hill ranges ext5d = _m miles1 at altitudes ( ?ree & f\r hundr$ feet1 ! upp] atmosph]e may be affect$ = a ?\s& feet above4 ,pr(4 ,l[e1 9 mak+ a flight ) a balloon1 f ,c9c9nati to ,nor? ,c>ol9a1 :i* la/$ a day & all ( "o night1 f\nd t dur+ ! e>ly morn+ ! balloon1 = "s reason1 began to asc5d1 & climb$ ne>ly five ?\s& feet 9 a few h\rs1 & z unacc\ntably began to desc5d sev]al h\rs be=e he l&$4 ,be=e x began to asc5d1 he 0 on ! we/]n side ( ! great m\nta9 range :i* ext5ds s\? f ,p5nsylvania & t]m9ates 9 ,georgia4 ,he 0 actually climb+ ! m\nta9 9 a drift ( air :i* 0 mov+ ea/w>dly1 & at no "t 0 he )9 f\r ?\s& feet ( ! e>? dur+ t p]iod1 :i* %[s t air movem5ts are ( su* a "* z to ex]t _! influ5ce v]tically to great heights4 ,= cross c\ntry fly+ ! safe/ altitude is #ajjj feet1 a di/ance :i* gives ample opportunity to volplane1 if necess>y1 & x is a height :i* enables ! pilot to make obs]vations ( ! surface s z to be able to judge ( its "*4 ,b explanations & /atem5ts1 & ! exp]i5ces ( pilots might be detail$ 9 pages1 & /ill x w\ld be ineffectual to tea* ! art ( fly+4 ,! only sure c\rse is to d ! "w on an actual ma*9e4 ,_m ( ! exp]i5ces are valuable to ! le>n]1 "s are m]ely 9 ! nature ( cautions1 & x is advisable = ! beg9n] to le>n :at ! exp]i5ces ( o!rs h be51 al?\gh !y may nev] be call$ ^u to duplicate !m4 ,all agree t at great elevations ! fly+ conditions are entirely diff]5t f ^? met ) ne> ! surface ( ! gr\nd1 & ! hi/ory ( accid5ts %[ t 9 e case :]e a mi%ap 0 _h at high altitude x came ab\t ?r\gh defect 9 ! ma*9e1 & n f gu/s or bad air condition4 ,on ! o!r h&1 ! uptilt+ ( ma*9es1 ! accid5ts due to ! s-call$ ,holes 9 ! air1 :i* h dott$ ! hi/oric pages ) accid5ts1 7 br\ght ab\t at l[ altitudes4 ,at f two to five ?\s& feet ! air may be mov+ at spe$s ( f tw5ty to =ty miles an h\r1--great masses ( w9ds1 l ! trade /ream1 :i* are uni=m ov] va/ areas4 ,to ! aviator fly+ 9 su* a field1 ) ! e>? hidd5 f him1 !re w\ld be no w9d to indicate t he 0 mov+ 9 any p>ticul> direction4 ,he w\ld fly 9 t m$ium1 9 any direction1 )\t ! slighte/ s5se t he 0 9 a gale4 ,x w\ld n affect ! control ( ! ma*9e1 because ! air1 ?\gh mov+ z a mass1 w\ld be ! same z fly+ 9 /ill air4 ,x is only :5 he sees fix$ objects t he is consci\s ( ! movem5t ( ! w9d4 ,,*apt] ,,xiii ,,! ,,propell] ,,by f> ! mo/ difficult problem connect$ ) aviation is ! propell]4 ,x is ! "o great vital elem5t 9 ! sci5ce & art p]ta9+ to ?is subject :i* has n advanc$ 9 ! slighte/ degree s9ce ! fir/ ma*9e 0 laun*$4 ,! eng9e has come 9 = a f> great] %>e ( exp]t exp]im5tal "w1 & has advanc$ mo/ rapidly dur+ ! pa/ t5 ye>s4 ,b1 /range to say1 ! propell] is1 ess5tially1 ! same ) ! exception ( a few small *anges4 ,,propell] ,,*anges4--,! *anges :i* h be5 made p]ta9+ to ! =m ( /ructure1 pr9cipally1 & 9 ! use ( new mat]ials4 ,! k9d ( wood mo/ suitable has be5 discov]$1 b ! l9es are ! same1 & no?+ has be5 done to fill ! requirem5t :i* gr[s out ( ! diff]5ce 9 spe$ :5 a ma*9e is 9 ! act ( laun*+ & :5 x is 9 full flight4 ,,propell] ,,%ape4--,x _c be possible t ! pres5t %ape ( ! propell] w be its ultimate =m4 ,x is inconceivable t ! propell] is s ineffici5t t only "o sixty-fif? ( ! p[] ( ! eng9e is available4 ,! improvem5t 9 propell] effici5cy is a direction :i* calls = exp]im5tal "w on ! "p ( inv5tors ev]y:]e4 ,! mak+ ( a propell]1 al?\gh x appe>s a difficult task1 is n z complicat$ z w\ld appe>1 & ) ! object 9 view ( mak+ ! subject readily und]/ood1 an explanation w be giv5 ( ! t]ms ,diamet]1 & ,pit*1 z us$ 9 ! art4 ,! ,diamet] has ref]5ce to ! l5g? ( ! propell]1 f end to end4 ,9 calculat+ propell] pull1 ! diamet] is t :i* indicates ! spe$ ( travel1 & = ?is reason is a necess>y elem5t4 ,?us1 = in/ance1 a propell] ?ree feet 9 diamet]1 rotat+ #ejj times a m9ute1 has a tip spe$ ( #aejj feet1 :]eas a six foot propell]1 rotat+ at ! same spe$1 moves #cjjj feet at ! tips4 ,,pit*4--,?is is ! t]m :i* is mo/ confus+1 & is t :i* causes ! mo/ frequ5t tr\ble 9 ! m9d ( ! novice4 ,! t]m w be made cle> by c>efully exam9+ ! accompany+ illu/ration & ! foll[+ description3 ,9 ,fig4 #gf is %[n a side view ( a propell] ,a1 m\nt$ on a %aft ,b1 :i* is free to move longitud9ally4 ,suppose we turn ! %aft s ! tip w move along on ! l9e indicat$ by ! arr[ ,c4 ,n[ ! pit* ( ! blade at ,d is su* t x w be exactly 9 l9e ) ! spirally-=m$ c\rse ,e1 = "o complete turn4 ,z ! propell] %aft has n[ advanc$1 along ! l9e ,e1 & /opp$ aft] "o turn1 at ,f1 ! measure betwe5 ! po9ts ,f & ,g repres5ts ! pit* ( ! propell]4 ,ano!r way to express x w\ld be to call ! angle ( ! blade a five1 or six1 or a sev5 foot pit*1 z ! pit*es are measur$ 9 feet4 ,fig4 #gf4 ,describ+ ! ,pit* ,l9e4 ,9 ! illu/ration ?us giv5 ! propell] %aft1 hav+ advanc$ six feet1 we h :at is call$ a six foot pit*4 ,n[1 to lay out su* a pit* is an easy matt]4 ,assume1 z 9 ,fig4 #gg1 t ,a repres5ts ! end ( ! blank f :i* ! propell] is to be cut1 & t ! diamet] ( ?is blank1 or its l5g? f end to end is sev5 feet4 ,! problem n[ is to cut ! blades at su* an angle t we %all h a six foot pit*4 ,fig4 #gg4 ,lay+ out ! ,pit*4 ,,lay+ ,,out ,,! ,,pit*4--,fir/1 we mu/ get ! circumf]5ce ( ! propell]1 t is1 ! di/ance ! tip ( ! propell] w travel 9 mak+ "o complete turn4 ,?is is done by multiply+ #g by #c4adaf4 ,?is equals #ba4ii1 or1 practically1 #bb feet4 ,a l9e ,b is drawn1 ext5d+ out horizontally along "o side ( ! blank ,a1 ?is l9e be+ made on a scale1 to repres5t #bb feet4 ,secondly1 at ! end ( ?is l9e drawn a p]p5dicul> l9e ,c1 #f feet long4 ,a p]p5dicul> l9e is always "o :i* is at "r angles to a base l9e4 ,9 ?is case ,b is ! base l9e4 ,l9e ,c is made #f feet long1 because we are try+ to f9d ! angle ( a #f foot pit*4 ,if1 n[1 a l9e ,d is drawn f ! ends ( ! two l9es ,b1 ,c1 x w repres5t ! pit* :i*1 m>k$ across ! end ( ! blank ,a1 w indicate ! l9e to cut ! blade4 ,,pit* ,,rule4--,! rule may1 !re=e1 be /at$ z foll[s3 ,multiply ! diamet] 79 feet7 ( ! propell] by #c4adaf1 & draw a l9e ! l5g? indicat$ by ! product4 ,at "o end ( ?is l9e draw a p]p5dicul> l9e ! l5g? ( ! pit* requirem5t 79 feet71 & jo9 ! ends ( ! two l9es by a diagonal l9e1 & ?is l9e w repres5t ! pit* angle4 ,propell]s may be made ( wood or metal1 ! =m] be+ pref]r$ = ! reason t ?is mat]ial makes a light] article1 & is /rong]1 9 "s respects1 ?an any metal yet sugge/$4 ,,lam9at$ ,,con/ruction4--,all propell]s %\ld be lam9at$1--t is1 built up ( lay]s ( wood1 glu$ toge!r & ?or\ghly dri$1 f :i* ! propell] is cut4 ,a product ?us made is mu* m s]viceable ?an if made ( "o piece1 ev5 ?\gh ! lam9at$ p>ts are ( ! same wood1 because ! diff]5t /rips us$ w h _! fib]s ov]lapp+ ea* o!r1 & ?us greatly augm5t ! /r5g? ( ! :ole4 ,g5]ally ! alt]nate /rips are ( diff]5t mat]ials1 black walnut1 mahogany1 bir*1 spruce1 & maple be+ ! mo/ l>gely us$1 b mahogany & bir* seem to be mo/ly favor$4 ,,lay+ ,,up ,a ,,propell] ,,=m4--,! fir/ /ep necess>y is to prep>e ?9 /rips1 ea*1 say1 sev5 feet long1 & five in*es wide1 & ?ree- eigh?s ( an in* ?ick4 ,if sev5 su* pieces are put toge!r1 z 9 ,fig4 #gh1 x w make an assemblage ( two & five-eigh? in*es high4 ,fig4 #gh4 ,a ,lam9at$ ,blank4 ,bore a hole c5trally ?r\gh ! assemblage1 & place !re9 a p9 ,b4 ,! contact faces ( ^! /rips %\ld be previ\sly well pa9t$ ov] ) hot glue lib]ally appli$4 ,:5 !y are !n plac$ 9 position & ! p9 is 9 place1 ! ends ( ! sep>ate pieces are (fset1 "o beyond ! o!r1 a half in*1 z %[n1 = in/ance1 9 ,fig4 #gi4 ,?is w provide ends :i* are eight & a half in*es broad1 & ?us furni% suffici5t mat]ial = ! blades4 ,! mass is !n subject$ to heavy pressure1 & all[$ to dry be=e ! blades are p>$ d[n4 ,fig4 #gi4 ,arrang+ ! ,/rips4 ,,mak+ ,,wide ,,blades4--,if a wid] blade is desir$1 a great] numb] ( /eps may be made by add+ ! requisite numb] ( /rips2 or1 ! /rips may be made ?ick]4 ,9 _m propell]s1 n to exce$ f\r diff]5t /rips are ?us glu$ toge!r4 ,! numb] is optional ) ! mak]4 ,an end view ( su* an assemblage ( /rips is illu/rat$ 9 ,fig4 #hj4 ,! next /ep is to lay (f ! pit*1 ! me?od ( obta9+ :i* has be5 expla9$4 ,fig4 #hj4 ,end view ( ,blank4 ,be=e />t+ "w ! sides1 z well z ! ends1 %\ld be m>k$1 & c>e obs]v$ to place a di/9ctive m>k on ! front side ( ! propell]4 ,ar\nd ! p9 ,b1 ,fig4 #ha1 make ,s-%ap$ m>ks ,c1 to indicate :]e ! cuts on ! faces ( ! blades are to beg94 ,!n on ! ends ( ! block2 scribe ! pit* angle1 :i* is indicat$ by ! diagonal l9e ,d1 ,fig4 #hj4 ,fig4 #ha4 ,m>k+ ! ,side4 ,?is l9e is on ! re> side ( ! propell]1 & is p]fectly /raight4 ,along ! front ( ?is l9e is a b[l9e ,e1 :i* indicates ! front surface ( ! propell] blade4 ,,propell] ,,outl9e4--,:ile ! m>ks ?us giv5 %[ ! angles1 & are design$ to indicate ! two faces ( ! blades1 !re is /ill ano!r important elem5t to be consid]$1 & t is ! f9al outl9e ( ! blades4 ,fig4 #hb4 ,outl9+4 ,x is obvi\s t ! outl9e may be v>i$ s t ! entire wid? at #a1 ,fig4 #hb1 may be us$1 or x may h an outl9e1 z repres5t$ by ! l9e #b1 9 ?is figure1 s t ! wide/ "p w be at or ne> ! dott$ l9e #c1 say two-?irds ( ! di/ance f ! c5t] ( ! blade4 ,?is is ! practice ) mo/ ( ! manufactur]s at ! pres5t "t1 & "s ( !m claim t ?is =m produces ! be/ results4 ,,= ,,high] ,,spe$s4--,fig4 #hc %[s a propell] cut f a blank1 #d x #f 9 cross section1 n lam9at$4 ,fig4 #hc4 ,cut f a #d x #f ,s+le ,blank4 ,x %\ld be borne 9 m9d t = high spe$s ! blades mu/ be n>r[4 ,a propell] sev5 feet 9 diamet] ) a six foot pit*1 turn+ #iej revolutions p] m9ute1 w produce a pull ( #cej p\nds1 if prop]ly made4 ,su* a propell] c be readily h&l$ by a =ty horse p[] motor1 su* z are specially con/ruct$ = fly+ ma*9e purposes4 ,,increas+ ,,propell] ,,effici5cy4--,"s exp]im5ts h be5 made lately1 :i*1 x is claim$1 l>gely increase ! effici5cy ( propell]s4 ,! improvem5t is direct$ to ! outl9e %ape ( ! blade4 ,! typical propell]1 su* z we h illu/rat$1 is "o ) ! wide "p ( ! blade at ! extremity4 ,! new type1 z sugge/$1 rev]ses ?is1 & makes ! wide "p ( ! blade ne> ! hub1 s t x gradually tap]s d[n to a n>r[ tip4 ,su* a =m ( con/ruction is %[n 9 ,fig4 #hd4 ,?is outl9e has "s advantages f "o /&po9t1 namely1 t x utilizes t "p ( ! blade ne> ! hub1 to produce a pull1 & does n relegate all ! duty to ! extreme ends or tips4 ,fig4 #hd4 ,a ,sugge/$ ,=m4 ,to und]/& ?is m fully1 let u take a propell] six feet 9 diamet]1 & measure ! pull or ?ru/ at ! tips1 & also at a po9t half way betwe5 ! tip & ! hub4 ,9 su* a propell]1 if ! blade is ! same wid? & pit* at ! two po9ts nam$1 ! pull at ! tips w be f\r times great] ?an at ! int]m$iate po9t4 ,,*apt] ,,xiv ,,exp]im5tal ,,glid]s ,,& ,,model ,,a]oplanes ,,an amus+ & v in/ructive pa/ime is af=d$ by con/ruct+ & fly+ glid+ ma*9es1 & op]at+ model a]oplanes1 ! latt] be+ equipp$ ) _! own p[]4 ,abroad ?is "w has be5 v successful z a means ( int]e/+ boys1 &1 inde$1 m5 :o h tak5 up ! sci5ce ( aviation are giv+ ?is sport s]i\s ?\ght & /udy4 ,:5 a ma*9e ( small dim5sions is made ! boy wond]s :y a l>ge ma*9e does n be> ! same relation 9 weight z a small ma*9e4 ,?is is "o ( ! fir/ lessons to le>n4 ,,! ,,relation ,,( ,,models ,,to ,,fly+ ,,ma*9es4 --,a model a]oplane1 say two feet 9 l5g?1 :i* has1 we w assume1 #ej squ>e in*es ( support+ surface1 seems to be a v rigid /ructure1 9 proportion to its weight4 ,x may be dropp$ f a consid]able height )\t injur+ x1 s9ce ! weight is only betwe5 two & ?ree ounces4 ,an a]oplane tw5ty times ! l5g? ( ?is model1 h[ev] /rongly x may be made1 if dropp$ ! same di/ance1 w\ld be cru%$1 & probably brok5 into fragm5ts4 ,if ! l>ge ma*9e is tw5ty times ! dim5sions ( ! small "o1 x w\ld be =ty feet 9 l5g?1 &1 proportionally1 w\ld h only sev5 squ>e feet ( su/a9+ surface4 ,b an op]ative ma*9e ( t size1 to be at all rigid1 w\ld require m ?an tw5ty times ! mat]ial 9 weight to be equal 9 /r5g?4 ,x w\ld weigh ab\t #hjj p\nds1 t is1 #dhjj times ! weight ( ! model1 & in/ead ( hav+ tw5ty times ! plane surface w\ld require "o ?\s& times ! spread4 ,x is ?is peculi>ity betwe5 models & ! actual fly]s t = ye>s made ! "q ( fly+ a problem :i*1 on ! basis ( pure calculation alone1 seem$ to (f] a negative2 & _m sci5tific m5 decl>$ t practical fly+ 0 an impossibility4 ,,lessons ,,f ,,models4--,m51 & boys1 too1 c le>n a useful lesson f ! model a]oplanes 9 o!r directions1 h[ev]1 & ! pr9cipal ?+ is ! "o ( /ability4 ,:5 ev]y?+ is consid]$ ! =m or %ape ( a fly+ model w s]ve to make a l>ge fly]4 ,! mann] ( balanc+ "o w be a good crit]ion = ! o!r 9 practice1 & exp]im5t+ ) ^! small devices is1 !re=e1 mo/ in/ructive4 ,! diff]5ce betwe5 glid]s & model a]oplanes is1 t glid]s mu/ be made mu* light] because !y are design$ to be project$ ?r\gh ! air by a kick ( "s k9d4 ,,fly+ ,,model ,,a]oplanes4--,model a]oplanes conta9 _! own p[] & propell]s :i*1 :ile !y may run = a few seconds only1 s]ve ! purpose ( indicat+ h[ ! propell] w act1 & 9 :at respect ! su/a9+ surfaces are effici5t & prop]ly arrang$4 ,x is n our purpose to give a treatise on ?is subject b to conf9e ?is *apt] to an exposition ( a few ( ! glid]s & model =ms :i* are f\nd to be mo/ effici5t = exp]im5tal "w4 ,,an ,,effici5t ,,glid]4--,probably ! simple/ & mo/ effici5t glid]1 & "o :i* c be made 9 a few mom5ts1 is to make a copy ( ! deltoid kite1 previ\sly ref]r$ to4 ,?is is m]ely a triangul>ly-%ap$ piece ( pap]1 or /iff c>dbo>d ,a1 ,fig4 #hd1 creas$ 9 ! middle1 along ! dott$ l9e ,b1 ! side w+s ,c1 ,c1 be+ b5t up s z to =m1 :at are call$ di$ral angles4 ,?is may be %ot ?r\gh ! air by a flick ( ! f+]1 ) ! po9t$ end =emo/1 :5 us$ z a glid]4 ,fig4 #he4 ,deltoid ,glid]4 ,,! ,,deltoid ,,=mation4--,?is same =m may be advantage\sly us$ z a model a]oplane1 b 9 t case ! broad end %\ld be =emo/4 ,fig4 #hf4 ,! ,deltoid ,rac]4 ,fig4 #hf %[s ! deltoid glid]1 or a]oplane1 ) ?ree cross braces1 ,a1 ,b1 ,c1 9 ! two =w>d braces ( :i* are j\rnal$ ! propell] %aft ,d1 s t ! propell] ,e is at ! broad end ( ! glid]4 ,a %ort /em ,f ?r\gh ! re> brace ,c1 provid$ ) a crank1 has its inn] end connect$ ) ! re> end ( ! %aft ,d by a rubb] b& ,g1 by :i* ! propell] is driv54 ,a tail may be atta*$ to ! re> end1 or at ! apex ( ! planes1 s x c be set = ! purpose ( direct+ ! angle ( flight1 b x w be f\nd t ?is =m has rem>kable /ability 9 flight1 & w move =w>dly 9 a /raight l9e1 always mak+ a graceful d[nw>d movem5t :5 ! p[] is exhau/$4 ,x seems to be a =m :i* has equal /abiliz+ p[]s :e!r at sl[ or at high spe$s1 ?us diff]+ ess5tially f _m =ms :i* require a c]ta9 spe$ 9 ord] to get ! be/ results4 ,,rac+ ,,models4--,"h & 9 ,engl& _m rac+ models h be5 made1 g5]ally ( ! ,a-%ap$ type1 :i* w be expla9$ h]e9aft]4 ,su* models are also /rong1 & able to )/& ! torsional /ra9 requir$ by ! rubb] :i* is us$ = ex]t+ ! p[]4 ,x is un=tunate t !re is n "s type ( *eap motor :i* is light1 & adapt$ to run = sev]al m9utes1 :i* w\ld be ( great value 9 "w ( ?is k9d1 b 9 ! abs5ce ( su* me*anism rubb] b&s are f\nd to be mo/ s]viceable1 giv+ bett] results ?an spr+s or b[s1 s9ce ! latt] are bo? too heavy to be available1 9 proportion to ! am\nt ( p[] develop$4 ,unlike ! l>ge a]oplanes1 ! support+ surfaces1 9 ! models1 are at ! re> end ( ! frames1 ! po9t$ ends be+ 9 front4 ,fig4 #hg4 ,a-,%ap$ ,rac+ ,glid]4 ,fig4 #hg %[s ! g5]al design ( ! ,a- %ap$ glid+ plane or a]oplane4 ,?is is compos$ ( ma9 frame pieces ,a1 ,a1 runn+ =e & aft1 jo9$ at _! re> ends by a cross b> ,b1 ! ends ( :i* project out slightly beyond _! juncture ) ! side b>s ,a1 ,a4 ,^! project+ ends h holes drill$ !re9 to receive ! %afts a1 a1 ( ! propell] ,d1 ,d4 ,a ma9 plane ,e is m\nt$ transv]sely across ?is frame at its re> end1 :ile at its =w>d end is a small plane1 call$ ! elevator4 ,! po9t$ end ( ! frame has on ea* side a turnbuckle ,g1 = ! purpose ( w9d+ up ! %aft1 & ?us twi/+ ! propell]1 al?\gh ?is is usually disp5s$ )1 & ! propell] itself is turn$ to give suffici5t twi/ to ! rubb] = ?is purpose4 ,,! ,,p[] ,,= ,,model ,,a]oplanes4--,"o end ( ! rubb] is atta*$ to ! hook ( ! %aft ,c1 & ! o!r end to ! hook or to ! turnbuckle ,g1 if x %\ld be s equipp$4 ,! rubb]s are twi/$ 9 opposite directions1 to correspond ) ! twi/ ( ! propell] blades1 & :5 ! propell]s are p]mitt$ to turn1 _! grip on ! air w cause ! model to %oot =w>dly1 until ! rubb]s are untwi/$1 :5 ! ma*9e w gradually glide to ! gr\nd4 ,,mak+ ,,! ,,propell]4--,^! %\ld h ! pit* uni=m on bo? ends1 & a simple little device c be made to hold ! twi/$ blade aft] x has be5 /eam$ & b5t4 ,bir* & holly are good woods = ! blades4 ,! /rips %\ld be made ?9 & !n boil$1 or1 :at is bett] /ill1 %\ld be plac$ 9 a deep pan1 & held on a grid above ! wat]1 s !y w be ?or\ghly /eam$4 ,!y are !n tak5 out & b5t by h&1 or secur$ betwe5 a =m specially prep>$ = ! purpose4 ,! device %[n 9 ,fig4 #hh %[s a base bo>d :i* has 9 ! c5t] a pair ( p>allel p9s ,a1 ,a1 slightly sep>at$ f ea* o!r4 ,fig4 #hh4 ,mak+ ! ,propell]4 ,at ea* end ( ! base bo>d is a pair ( holes ,c1 ,d1 drill$ 9 at an angle1 ! angles be+ ! pit* desir$ = ! ends ( ! propell]4 ,9 "o ( ^! holes a p9 ,e is plac$1 s ! p9s at ! opposite ends project 9 diff]5t directions1 & ! tips ( ! propell] are held aga9/ ! ends ( ^! p9s1 :ile ! middle ( ! propell] is held betwe5 ! p>allel p9s ,a1 ,a4 ,! two holes1 at ! two angles at ! ends ( ! bo>d1 are = ! purpose ( mak+ "r & left h& propell]s1 z x is desirable to use two propell]s ) ! ,a-%ap$ model4 ,two propell]s ) ! deltoid model are n s necess>y4 ,aft] ! twi/ is made & ! blade prop]ly secur$ 9 position x %\ld be all[$ to ?or\ghly dry1 & aft]w>ds1 if x is coat$ ) %ellac1 w n untwi/1 z x is ! *ang+ "* ( ! atmosph]e :i* usually causes ! twi/$ /rips to *ange _! positions4 ,%ellac prev5ts ! moi/ atmosph]e f affect+ !m4 ,,mat]ial ,,= ,,propell]s4--,v light propell]s c also be made ( ?91 anneal$ alum9um %eets1 & ! p9s 9 t case w s]ve z guides to enable y to get ! desir$ pit*4 ,fib] bo>d may also be us$1 b ?is is m difficult to h&le4 ,ano!r good mat]ial is celluloid %eets1 :i*1 :5 cut into prop] /rips1 is dipp$ 9 hot wat]1 = b5d+ purposes1 & x readily reta9s its %ape :5 cool$4 ,,rubb]--,suitable rubb] = ! /rips are readily obta9able 9 ! m>ket4 ,exp]im5t w soon %[ :at size & l5g?s are be/ adapt$ = ! p>ticul> type ( propell]s :i* y succe$ 9 mak+4 ,,propell] ,,%ape ,,& ,,size4--,a good proportion ( propell] is %[n 9 ,fig4 #hi4 ,?is also %[s ! =m & mann] ( connect+ ! %aft4 ,! latt] ,a has a hook ,b on "o end to :i* ! rubb] may be atta*$1 & its o!r end is flatt5$1 z at ,c1 & secur$ to ! blade by two-po9t$ brads ,d1 cl9*$ on ! o!r side4 ,fig4 #hi4 ,%ape & ,size4 ,! coll> ,e is sold]$ on ! %aft1 & 9 practice ! %aft is plac$ ?r\gh ! be>+ hole at ! end ( ! frame be=e ! hook is b5t4 ,,support+ ,,surfaces4--,! support+ surfaces may be made p]fectly flat1 al?\gh 9 ?is p>ticul> x w\ld be well to obs]ve ! rules ) respect to ! camb] ( l>ge ma*9es4 ,,*apt] ,,xv ,,! ,,a]oplane ,,9 ,,! ,,great ,,w> ,,dur+ ! civil w> ! ,f$]al =ces us$ captive balloons = ! purpose ( discov]+ ! positions ( ! enemy4 ,!y 7 ( great s]vice at t "t1 al?\gh !y 7 /ation$ f> )9 ! l9es to prev5t ho/ile guns f rea*+ !m4 ,,balloon ,,obs]vations4--,necess>ily1 obs]vations f balloons 7 & are imp]fect4 ,x 0 f\nd to be v unsatisfactory dur+ ! ,russian-,japanese w>1 because ! angle ( vision is v l[1 &1 fur!rmore1 at su* di/ances ! movem5ts1 or ev5 ! location ( troops is n obs]vable1 except "u ! mo/ favorable conditions4 ,balloon obs]vation dur+ ! progress ( a battle is absolutely useless1 because ! smoke f ! fir+ l9e is1 necess>ily1 betwe5 ! balloon & ! enemy1 s t ! a]ial sc\t has no opportunity to make any obs]vations1 ev5 9 deta*$ portions ( ! fight+ zone1 :i* are ( any value to ! comm&]s4 ,,*ang$ ,,conditions ,,( ,,w>f>e4--,s9ce our great w>1 conditions p]ta9+ to guns h be5 revolutioniz$4 ,n[ ! ranges are s great t captive balloons w\ld h to be locat$ f> 9 ! re>1 & at su* a great di/ance f ! fir+ l9e t ev5 ! be/ field glasses w\ld be useless4 ,! sci5ce ( w> has also evolv$ ano!r condition4 ,soldi]s are no long] expos$ dur+ artill]y attacks4 ,uni=ms are made to imitate natural objects4 ,! khaki suits 7 design$ to imitate ! yell[ veldts ( ,s\? ,africa2 ! gray-gre5 g>m5ts ( ! ,g]man =ces are design$ to simulate ! gre5 fields ( ! nor?4 ,,! ,,ef=t ,,to ,,conceal ,,combatants4--,! ,fr5* h disc>d$ ! hi/oric r$ tr\s]s1 & ! elim9ation ( lace1 :ite gloves1 & o!r telltale insignias ( ! (fic]s1 h be5 disp5s$ ) by special ord]s4 ,9 ! great ,european w> armies h burr[$ 9 ! e>? along battle l9es hundr$s ( miles 9 l5g?2 made cov]$ tr5*es2 prep>$ artificial groves to conceal batt]ies1 & 9 _m +5i\s ways endeavor$ to make ! battlefield an imitation field ( nature4 ,,smokeless ,,p[d]4--,:ile smokeless p[d] has be5 utiliz$ to /ill fur!r hide a fight+ =ce1 x has1 9 a measure1 uncov]$ itself1 z ! battlefield is n n[1 z 9 old5 times1 ov]spread ) masses ( roll+ smoke4 ,nev]!less1 ov] e battlefield !re is a haze :i* c be p5etrat$ only f above1 h5ce ! possibilities ( utiliz+ ! a]oplane 9 w> became ! mo/ important /udy ) all nations1 z soon z fly+ became an accompli%$ fact4 ,,inv5tions ,,to ,,attack ,,a]ial ,,craft4--,be=e any nation _h ! opportunity to make an actual te/ on ! battlefield1 inv5tors 7 at "w to devise a means :]eby an a]ial foe c\ld be met4 ,9 a measure ! a]ial gun has be5 successful1 b mon?s ( w> has %[n t ! a]oplane is "o ( ! /ronge/ arms ( ! s]vice 9 actual w>f>e4 ,x 0 assum$ prior to ! ,european w> t ! *ief function ( ! a]oplane w\ld be ! dropp+ ( bombs1--t is = s]vice 9 attack+ a foe4 ,actual practice has n ju/ifi$ ?is !ory4 ,9 "s places ! appe>ance ( ! a]oplane has caus$ t]ror1 b x has be5 f\nd ! great value is its sc\t+ advantages4 ,,function ,,( ,,! ,,a]oplane ,,9 ,,w>4--,:ile bomb ?r[+ may 9 ! future be p]fect$1 x is n at all an easy problem = an aviator to d "w :i* is comm5surate ) ! risk involv$4 ,! range is g5]ally too great2 ! necessity ( swift movem5t 9 ! ma*9e too spe$y to assure accuracy1 & to attack a foe at haphaz>d po9ts c nev] be effectual4 ,ev5 ! sl[ly-mov+ gas fields1 l ! ,zeppel91 _c deliv] bombs ) any degree ( precision or accuracy4 ,,bomb-,,?r[+ ,,te/s4--,x is int]e/+1 h[ev]1 to und]/& h[ an aviator kn[s :]e or :5 to drop ! bomb f a swiftly-mov+ ma*9e4 ,sev]al ?+s mu/ be tak5 into consid]ation1 su* z ! height ( ! ma*9e f ! e>?2 its spe$1 & ! p>abolic curve t ! bomb w take on its flight to ! e>?4 ,:5 an object is releas$ f a mov+ ma*9e x w foll[ ! ma*9e f :i* x is dropp$1 gradually rec$+ f x1 z x desc5ds1 s t ! ma*9e is actually beyond ! place :]e ! bomb /rikes ! e>?1 due to ! ret>d+ motion ( ! atmosph]e aga9/ ! missile4 ,! diagram ,fig4 #ij w aid ! boy 9 grasp+ ! situation4 ,a is ! air%ip2 ,b ! pa? ( its flight2 a ! c\rse ( ! bomb aft] x leaves ! air%ip2 & ,d ! e>?4 ,! "q is h[ to det]m9e ! prop] movem5t :5 to release ! bomb4 ,,me?od ,,= ,,det]m9+ ,,movem5t ,,( ,a ,,bomb4--,lieut4 ,scott1 ,u4 ,s4 ,a41 ( ! ,coa/ ,survey ,artill]y1 sugge/$ a me?od = det]m9+ ^! que/ions4 ,x 0 necess>y to asc]ta91 fir/1 ! altitude & spe$4 ,:ile ! b>omet] is us$ to det]m9e altitudes1 x is obvi\s t spe$ is a matt] mu* m difficult to asc]ta91 ow+ to ! w9d movem5ts1 :i* 9 all cases make x difficult = a fli] to det]m9e1 ev5 ) in/rum5ts :i* h be5 devis$ = ! purpose4 ,fig4 #ij4 ,c\rse ( a ,bomb4 ,in/ead1 !re=e1 ( rely+ on ! b>omet]1 ! %ip is equipp$ ) a telescope :i* may be in/antly set at an angle ( #de degrees1 or v]tically4 ,?us1 ,fig #ia %[s a %ip ,a1 on :i* is m\nt$ a telescope ,b1 at an angle ( #de degrees4 ,! obs]v] fir/ notes ! object along ! l9e ( #de degrees1 & />ts ! "t ( ?is obs]vation by a /op wat*4 ,! telescope is !n turn$ s x is v]tical1 z at ,c1 & ! obs]v] wat*es ?r\gh ! telescope until ! ma*9e passes directly ov] ! object1 :5 ! wat* is /opp$1 to indicate ! "t betwe5 ! two obs]vations4 ,fig4 #ia4 ,det]m9+ ,altitude & ,spe$4 ,! height ( ! ma*9e along ! l9e ,d is ?us equal to ! l9e ,e f ,b to ,c1 & ! "t ( ! flight f ,b to a be+ ?us kn[n1 z well z ! height ( ! ma*9e1 ! obs]v] consults specially-prep>$ tables :i* %[ j :at k9d ( a curve ! bomb w make at t height & spe$4 ,all t is necess>y n[ is to set ! sight] ( ! telescope at ! angle giv5 9 ! tables1 & :5 ! object to be hit appe>s at ! sight1 ! bomb is dropp$4 ,,! ,,great ,,ext5t ,,( ,,mod]n ,,battle ,,l9es4-- ,! great w> br\ght into ! field su* /up5d\s masses ( m5 t ! battle l9es h ext5d$ ov] an unbrok5 front ( ov] #bjj miles4 ,9 ! battle ( ,wat]loo1 ab\t #adj1jjj m5 7 engag$ on bo? sides1 & ! battle front 0 less ?an six miles4 ,!re 71 ?us mass$1 along ! front1 ov] #bj1jjj m5 e mile ( ! way1 or #aj1jjj on ea* side4 ,9 ! conflict betwe5 ! ,allies & ! ,g]mans x is e/imat$ t !re 7 less ?an #gejj along ea* mile4 ,x 0 pr$ict$ 9 ! e>li] /ages ( ! w> t x w\ld be an easy matt] = ei!r side to sudd5ly mass su* an ov]:elm+ =ce at "o po9t z to enable ! attack+ p>ty to g ?r\gh ! oppos+ =ce l a w$ge4 ,su* tactics 7 (t5 employ$ by ,napoleon & o!r great ma/]s ( w>2 b 9 e ef=t :]e x has be5 attempt$ 9 ! pres5t conflict1 x 0 foil$4 ,! oppos+ =ce 0 ready to meet ! attack ) equal or sup]ior numb]s4 ,! eye ( ! army1 ! a]oplane1 detect$ ! movem5ts 9 e in/ance4 ,,! ,,a]oplane ,,detect+ ,,! ,,movem5ts ,,( ,,armies4--,9 ! e>ly /ages ( ! w>1 :5 ! ,g]mans drove ! left ( ! ,fr5* army t[>ds ,p>is1 ! _w expect$ an inve/m5t ( t city4 ,sudd5ly1 & = no app>5t reason1 ! ,g]man "r 0 =c$ back & comm5c$ to retreat4 ,x 0 n kn[n until weeks aft]w>ds t ! ,fr5* _h assembl$ a l>ge army to ! we/ & nor?we/ ( ,p>is1 ready to take ! ,g]mans 9 flank ! mom5t an attempt %\ld be made to encircle ! ,p>is =ts4 ,! ,g]man aviators1 fly+ ov] ,p>is1 discov]$ ! hidd5 army1 & x is well !y did s1 = x is c]ta9 if !y _h surr\nd$ ! outly+ =ts1 x w\ld h be5 an easy matt] = ! conceal$ =ces to de/roy _! communications1 & probably h =c$ ! surr5d] ( a l>ge "p ( ! besieg]s4 ,! a]oplane 9 w>f>e1 !re=e1 has con/antly not$ e disposition ( troops1 locat$ ! positions & judg$ ! de/9ation ( convoys2 ! batt]y emplacem5ts2 & ! direction 9 :i* l>ge =ces h be5 mov$ f "o "p ( ! l9e to ! o!r1 ?us keep+ ! comm&]s s well in=m$ t few surprises 7 possible4 ,,! ,,effective ,,height ,,= ,,sc\t+4--,x has be5 %[n t a]oplane sc\t+ is n effective at high altitudes4 ,x is n difficult = aviators to rea* & ma9ta9 altitudes ( five ?\s& feet & ov]1 b at t elevation x is impossible to di/+ui% any?+ b ! movem5t ( l>ge =ces4 ,,sizes ,,( ,,objects ,,at ,,great ,,di/ances4--,at a di/ance ( "o mile an automobile1 tw5ty feet 9 l5g?1 is ab\t z l>ge z a piece ( p5cil "o in* long1 view$ at a di/ance ( ?irty-five feet4 ,a company ( "o hundr$ m51 :i* 9 m>*+ ord]1 say f\r abrea/1 occupies a space ( eight by "o hundr$ feet1 looks to ! aviator ab\t z l>ge z an object "o in* 9 l5g?1 f\r & a half feet f ! eye4 ,! m>* ( su* a body ( m51 view$ at t di/ance1 is s small z almo/ to be imp]ceptible to ! eye ( an obs]v] at re/4 ,h[ mu* m difficult x is to di/+ui% a movem5t if ! obs]v] is 9 a rapidly-mov+ ma*9e4 ,= ^! reasons obs]vations mu/ be made at altitudes ( less ?an a mile1 & ! haz>d ( ^! ent]prises is1 !re=e1 v great1 s9ce ! successful sc\t mu/ br+ himself )9 range ( specially design$ guns1 :i* are effective at a range ( #cjjj y>ds or m1 kn[+ t 8 only hope ( safety lies 9 ! *ance t ! rapidly-mov+ ma*9e w avoid ! ra9 ( bullets t try to seek him out4 ,,"s ,,d>+ ,,feats ,,9 ,,w>4--,x w\ld be impossible to rec\nt ! _m rem>kable a]ial fights :i* h tak5 place 9 ! great w>4 ,"s ( !m seem to be unreal1 s />tl+ are ! tales t h be5 told4 ,we may well imag9e ! brav]y t w n]ve m5 to fight ?\s&s ( feet above ! e>?4 ,"o ( ! mo/ ?rill+ combats took place betwe5 a ,russian a]oplane & a ,zeppel91 ov] ,russian ,pol&1 at ! "t ( ! fir/ ,g]man invasion4 ,! ,zeppel9 0 so>+ ov] ! ,russian position1 at an altitude ( ab\t a mile4 ,a ,russian aviator asc5d$ & aft] circl+ ab\t1 s z to ga9 a position high] ?an ! air%ip1 d>t$ d[n1 & cra%$ into ! great gas field4 ,! aviator knew t x meant dea? to him1 b 8 devotion l$ him to make ! sacrifice4 ,! ,zeppel91 brok5 9 two1 & robb$ ( its gas1 sl[ly mov$ t[>d ! e>?1 !n gradually increas$ ! spe$ ( its desc5t1 z ! a]oplane clung to its %att]$ hulk1 & by ! "t x ne>$ ! e>? its velocity 0 great en\gh to assure ! de/ruction ( all on bo>d1 :ile ! %ip itself 0 cru%$ to atoms4 ,"o ( ! mo/ spectacul> fights ( ! w> occurr$ outside ,p>is1 :5 "o ( ! ,g]man ,taubes attempt$ to make its p]iodical t\r ( obs]vation4 ,"o ( ! ,fr5* a]oplanes1 :i* _h ! advantage ( great] spe$1 m\nt$ to a great] altitude1 & circl$ ab\t ! ,taube4 ,! latt] ) its ma*9e gun made a furi\s attack1 dur+ ^! maneuv]s1 b ! ,fr5* %ip did n reply until x 0 at su* an elevation t x c\ld deliv] ! attack f above4 ,!n its ma*9e gun 0 br\ght into play4 ,z 0 aft]w>ds discov]$1 ! w+s & body ( ! ,taube 7 completely riddl$1 & x 0 a m>vel h[ x 0 possible = ! ,g]man aviator to rema9 afloat z long z he did4 ,soon ! ,taube 0 notic$ to lur* f side to side1 & !n d>t d[nw>dly4 ,! monoplane1 9 ! pursuit1 gradually desc5d$1 b x 0 n able to foll[ ! de/roy$ ,taube to ! e>?1 z ! latt] f9ally turn$ ov]1 & w5t swirl+ to de/ruction4 ,! obs]v]1 z well z ! aviator1 _h bo? be5 kill$ by ! fire f ! monoplane4 ,9 ! tr5*es on ! ,m>ne1 to ! nor!a/ ( ,p>is1 :]e ! mo/ /ubborn conflict rag$ = ov] a week1 ! air 0 nev] cle> ( a]oplanes4 ,!y c\ld be se5 9 all directions1 & almo/ all types ( ma*9es 7 repres5t$4 ,! pr9cipal ones1 h[ev]1 7 monoplanes4 ,,! ,,g]man ,,taube4--,! ,g]man ,taube is a monoplane1 its ma9 support+ surfaces1 z well z ! tail planes1 are s con/ruct$ t !y repres5t a bird4 ,taube means dove4 ,x w\ld h be5 m appropriate to call x a hawk4 ,on ! o!r h&1 ! ,fr5* monoplane1 ( :i* ! ,bl]iot is ! be/ kn[n example1 has w+s ) well r\nd$ extremities1 & fl>+ tail1 s t ! two c be readily di/+ui%$4 ,on "o occasion1 dur+ ! lull 9 ! battle1 two ( ! ,taubes approa*$ ! area above ! ,fr5* l9es1 & aft] asc5d+ to a great height1 began ! volplane t[>d _! own l9es4 ,su* a maneuv] 0 f\nd to be ! mo/ advantage\s1 z x gave ! sc\t+ a]oplane ! advantage ( be+ able to discov] ! positions & movem5ts ) great] ease1 & at ! same "t1 9 case ( accid5t to ! ma*9e1 ! impetus ( ! flight w\ld be to _! own l9es4 ,?ree ( ! ,fr5* a]oplanes at once began _! circl+ flight1 m\nt+ high] & high]1 b )\t attempt+ to g ne> ! ,taubes4 ,:5 ! ,fr5* %ips _h ga9$ ! prop] altitude1 !y clos$ 9 t[>d ! ,g]man %ips1 be=e ! latt] c\ld rea* _! own l9es 9 _! volplan+ act4 ,?is meant t !y mu/ retreat or fight1 & ! crack ( ! guns %[$ t x meant a /ruggle4 ,! monoplanes circl$ ab\t ) incr$ible skill1 p\r+ =? %ot aft] %ot4 ,soon "o ( ! ,taubes 0 se5 to flutt]4 ,?is 0 ! signal = a m conc5trat$ attack on h]4 ,! army 9 ! tr5*es1 & on ! fields bel[1 witness$ ! novel combat4 ,! fly+ %ips 7 n[ approa*+ ! e>?1 b ! gunn]s bel[ d>$ n use _! guns1 because 9 ! maneuv]s !y w\ld be z likely to /rike fri5d z foe4 ,! w\nd$ ,taube 0 n[ %oot+ to ! e>?1 & ! two monoplanes began to give _! att5tion to ! o!r %ip1 :i* 0 attempt+ to escape to ! nor?4 ,! fla% ( ! guns ( all ! fli]s c\ld be pla9ly se51 b ! s\nds 7 dr[n$ by ! ro> ( ! great conflict all ab\t !m4 ,! ,taube c\ld n escape ! net ar\nd h]4 ,%e1 too1 0 doom$4 ,a %ot seem$ to /rike ! gasol9e tank1 & ! framework 0 soon envelop$ 9 flames4 ,!n %e turn$ sidewise1 z ! mat]ial on "o side burn$ away1 & skidd+ to ! left %e d>t$ to ! e>?1 a %apeless mass4 ,x 0 f\nd t ! aviator 0 n hurt by ! %ot1 b 01 und\bt$ly1 kill$ by ! impact ) ! e>?4 ,! obs]v] 0 riddl$ ) bullets1 & 0 likely dead be=e ! %ip rea*$ ! e>?4 ,9 ! we/]n conf9es ( ,belgium1 ne> ,ypres1 ! ,briti% employ$ num]\s aircraft1 _m ( !m biplanes1 & at all times !y 7 9 ! air1 report+ obs]vations4 ,_m ( ! fly+ fights h be5 record$1 & ! reports :5 publi%$ w be mo/ ?rill+ read+4 ,,h[ ,,a]oplanes ,,report ,,obs]vations4--,x may be ( "s int]e/ to "k h[ a]oplanes are able to report obs]vations to ! comm&]s 9 ! field1 f ! air%ip itself4 ,_m +5i\s devices h be5 devis$ = ?is purpose4 ,,signal ,,flags4--,! be/ kn[n & mo/ univ]sally us$ me?od is by ! use ( signal+ flags4 ,suppose ! comm&] ( a =ce is desir\s ( gett+ ! range ( a hidd5 batt]y1 or a mass$ =ce 9 8 front4 ,! obs]v] 9 ! a]oplane w sail ov] ! area at an und]/ood altitude1 say "o mile 9 height4 ,! (fic] 9 *>ge ( ! batt]y1 kn[+ ! height ( ! air%ip1 is able1 by means ( ! angle ?us giv5 him1 to get ! di/ance betwe5 8 batt]y & ! conceal$ po9t b5ea? ! air%ip4 ,! obs]v] 9 ! air%ip1 ( c\rse1 signals ! eng9e] (fic]1 ! exact po9t or "t :5 ! air%ip is directly above1 & ?is gives him ! correct angle4 ,! guns ( ! batt]y are !n direct$ & fir$ s z to rea* ! conceal$ po9t4 ,x is n[ important to be able to s5d intelligible signals to ! (fic] 9 *>ge ( ! batt]y4 ,if ! %ot goes beyond ! m>k1 ! obs]v] 9 ! air%ip raises ! flag above 8 head1 :i* indicates t x 0 too high4 ,,h[ ,,us$4--,if ! %ot fell %ort he w\ld l[] ! flag4 ,if ! %ot l&$ too f> to ! "r1 ?is w\ld be indicat$ by ! flag1 & if too f> to ! left1 ! signal w\ld1 9 l mann]1 be suffici5t to enable ! gunn]s to correct ! guns4 ,:5 ! exact range is obta9$ ! obs]v] 9 ! %ip waves ! flag ab\t 8 head1 9 tok5 ( approval4 ,all ?is "w ( not+ ! effect ( ! %ots mu/ be tak5 :ile ! air%ip is "u fire1 & :ile circl+ ab\t )9 visual range ( ! conceal$ object bel[4 ,! (fic] 9 *>ge ( ! batt]y1 z well z ! obs]v] on ! fly+ craft1 mu/ be equipp$ ) p[]ful glasses1 s ! effect ( ! %ots may be not$ on ! "o h&1 & ! signals prop]ly read by ! (fic] on ! o!r h&4 ,x may be said1 h[ev]1 t air battles h n be5 frequ5t & t !y h be5 m]ely incid5ts ( ! conditions "u :i* !y 7 op]at$4 ,! mission ( ! a]oplane is n[ conc$$ to be purely "o ( obs]vation1 su* z we h describ$4 ,bo? ,fr5* & ,g]man reports are full ( incid5ts %[+ ! value ( obs]vations1 & also conc]n+ ! effects ( bombs4 ,extracts f ! di>ies ( prison]s gave _m int]e/+ features ( ! results ( a]oplane "w4 ,,casualties ,,due ,,to ,,a]oplanes4--,9 ! di>y ( "o 0 f\nd ! rem>k3 ,i 0 lucky to escape ! bomb ?r[n by a ,fr5* aviator at ,conrobet1 :i* kill$ eight ( my companions4 ,ano!r says3 ,! ,sev5? ,company ( ! ,?ird ,regim5t ( ! ,gu>d _h eight kill$ & tw5ty-two w\nd$ by bomb f a ,fr5* a]oplane4 ,ano!r3 ,an (fic] %[$ u a torn coat tak5 f "o ( sixty soldi]s w\nd$ by a bomb f an a]oplane4 ,a prison] says3 ,ne> ,neuville an a]oplane bomb dropp$ on a supply tra91 kill$ f\r m51 w\nd$ six1 & kill$ a consid]able numb] ( horses4 ,! ,belgians1 aft] _! defeat & ! capture ( ,antw]p1 7 =c$ to ! we/ along ! coa/4 ,9 "s way !y le>n$ t ! ,kais] 0 ab\t to occupy a *ateau ne> ,dixmunde4 ,sev]al aviators flew above ! position & dropp$ a numb] ( bombs on ! build+1 completely wreck+ x1 & x 0 =tunate t ! ,emp]or left ! build+ only tw5ty m9utes be=e1 z sev]al ( 8 aides & soldi]s on duty 7 kill$4 ,on num]\s occasions ! headqu>t]s ( ! diff]5t comm&]s h be5 discov]$ & _h to be mov$ to saf] places4 ,dur+ all ^! wond]ful exploits :i* w live 9 hi/ory because m5 _h ! opportunity dur+ ! w> to use !m = ! fir/ "t 9 actual conflict1 ! (ficial reports h n m5tion$ ! aviators by "n4 ,! dea?s ( ! brave m5 h br\ght =? ! ackn[l$gm5ts ( _! s]vices4 ,dur+ ! fir/ ?ree mon?s ( ! w> x is e/imat$ t ov] sixty aviators & aides _h lo/ _! lives 9 ! conflict on ! two great battle l9es4 ,?is does n take into acc\nt ^? :o met dea? on ! ,zeppel9s1 ( :i* five _h be5 de/roy$ dur+ t "t4 ,,! ,,end ,,gloss>y ,,( ,,words ,,us$ ,,9 ,,text ,,( ,,?is ,,volume ,:]e a ^w has v>i\s mean+s1 t def9ition is giv5 :i* w express ! t]ms us$ by ! au?or 9 expla9+ ! me*anism or subject to :i* x ref]s4 ,aviation4 ,! art ( fly+4 ,altitude4 ,height2 a v]tical di/ance above any po9t4 ,attraction4 ,! art or process ( draw+ t[>ds4 ,allusion4 ,ref]r+ to a c]ta9 ?+4 ,assume4 ,tak+ x = grant$4 ,acc5tuat$4 ,to lay great /ress ^u a ?+4 ,angle ( ,movem5t4 ,any direction :i* is upw>dly or d[nw>dly1 z di/+ui%$ f ! direction ( movem5t :i* is ei!r to ! "r or to ! left4 ,acquire4 ,to obta92 to recov]2 to procure4 ,analog\s4 ,correspond+ to or resembl+ "s o!r ?+ or object4 ,air ,hole4 ,a t]m us$ to express a condition 9 fly+ :]e ! ma*9e :ile 9 horizontal flight takes a sudd5 drop1 due to c\nt] curr5ts4 ,ail]ons4 ,lit]ally1 small planes4 ,us$ to designate ! small planes :i* are design$ to /abilize a ma*9e4 ,angle4 ,a figure1 or two /raight l9es :i* />t at ! same po9t4 ,! sides ( ^! l9es are t]m$ ! angle4 ,analysis4 ,to sep>ate2 to take ap>t & exam9e ! v>i\s p>ts or elem5ts ( a ?+4 ,a]oplane4 ,any =m ( ma*9e :i* has planes1 & is heavi] ?an air4 ,usually a fly+ /ructure :i* is propell$ by "s motive p[]4 ,accumulation4 ,add+ to2 br++ toge!r ! same or unlike articles4 ,ascribable4 ,a ref]5ce to "s antec$5t s\rce4 ,a]onautics4 ,! sci5ce ( fly+4 ,ant]ior4 ,mean+ ! front or =w>d m>g9 or portion ( a body4 ,artifices4 ,any artificial product1 or workman%ip4 ,axially4 ,?r\gh ! c5tral portion4 ,?us1 ! %aft :i* goes ?r\gh a cyl9d] is axially arrang$4 ,automatic4 ,a ?+ :i* op]ates by its own me*anism2 a contrivance :i* is made 9 su* a mann] t x w run )\t manual op]ation or c>e4 ,al]tness4 ,quick2 be+ active4 ,apex4 ,! po9t at :i* two l9es meet2 also ! extreme po9t$ end ( a conical figure4 ,asc5sion4 ,mov+ upw>dly4 ,accessories4 ,! p>ts ( a ma*9e1 or artielee :i* may ha us$ 9 connection !re)4 ,anemomet]4 ,an in/rum5t = measur+ ! =ce or ! velocity ( w9d4 ,anemograph4 ,an in/rum5t t usually traces a curv$ l9e ,,oh pap] to make a record ( ! =ce or direction1 or velocity ( ! w9d4 ,anemometrograph4 ,a device :i* det]m9es ! =ce1 velocity & direction ( ! w9d4 ,accretion4 ,add+ to little by little4 ,accel]at$4 ,quiek5+2 hurry+ ! process4 ,abridg$4 ,p>tly tak5 away f2 %ort5$4 ,abrogate4 ,to disp5se )2 to set aside4 ,abnormal ,n 9 ! usual mann]2 n 9 a regul> way4 ,alt]nate4 ,fir/ "o & !n ano!r2 go+ f "o side to ! o!r4 ,anci5t ,lights4 ,an old ,engli% law :i* prev5ts a neighbor f %utt+ (f sunlight4 ,angul>ly4 ,a l9e :i* runs out f ano!r s t ! two are n p>allel4 ,an]oid4 ,n wet4 ,appli$ to ! type ( b>omet] :]e ! m$ium = det]m1in+ ! pressure is n made ( m]cury4 ,aspirate4 ,a t]m giv5 by ! ,fr5* to t peculi> action ( w+1 or o!r body1 :i*1 :5 plac$ 9 c]ta9 positions1 relative to a curr5t ( air1 w cause x to be drawn into ! curr5t4 ,assemblage4 ,! br++ toge!r ( ! p>ts or elem5ts ( a ma*9e4 ,augm5t4 ,to aid2 to add to or increase4 ,bank$4 ,! t]m us$ 9 aviation :i* indicates t ! ma*9e is turn$ up s t its support+ surfaces re/ aga9/ ! air1 z 9 alight+4 ,b>omet]4 ,an in/rum5t = det]m9+ ! air pressure1 & !reby indicat+ altitudes4 ,bevel ,p9ion4 ,a too!d :eel driv5 by a l>g] :eel4 ,bi-,plane4 ,two planes4 ,9 aviation t type :i* has two planes1 simil> 9 size1 usually1 & g5]ally plac$ "o above ! o!r s !y are sep>at$ ! same di/ance f ea* o!r1 z ! wid? ( ea* ( ! planes4 ,bulge4 ,a hump2 an enl>gem5t beyond ! normal at any po9t4 ,camb]1 also ,cambre4 ,! upw>d curve 9 a plane4 ,catapult4 ,a piece ( me*anism = project+ or ?r[+ a missile4 ,c>buret]4 ,! device :i* breaks up ! fuel oil1 & mixes ! prop] quantity ( air ) x be=e x is drawn into ! eng9e4 ,cata/rophe4 ,a calamity2 a sad end+2 loss ( life or ( prop]ty4 ,cellul>4 ,made up ( small holl[s1 or comp>tm5ts2 fill$ ) holes4 ,cele/ial4 ,p]ta9+ to ! heav5s4 ,c5trifugal4 ,t =ce :i* ?r[s outw>dly f a rotat+ body4 ,c5tripetal4 ,t =ce1 l ! attraction ( gravity1 :i* draws a body to ! c5t]4 ,*>act]i/ic4 ,/rik+2 t :i* is peculi> to "s ?+ or object4 ,comm5surate4 ,suffici5t2 9 prop] proportion2 suffici5t = ! occasion4 ,comm]cially4 ,p]ta9+ to ! nature ( trade2 ! mak+ ( money4 ,complicat$4 ,n easily expla9able2 n easy to sep>ate4 ,comp>atively4 ,judg$ by some?+ else2 tak5 ) ref]5ce to ano!r object or ?+4 ,compression4 ,! draw+ toge!r2 =c+ into a small] compass1 or space4 ,composition4 ,made up ( diff]5t elem5ts1 or ?+s4 ,conceivable4 ,made up f ! imag9ation4 ,concav$4 ,holl[$3 ,9 aviation x has ref]5ce to ! und]side ( ! plane1 :i* is usually provid$1 /ructurally1 ) a holl[ or tr\gh =mation4 ,con=m+4 ,to make alike 9 =m2 to br+ into h>mony4 ,conjunction4 ,9 eonneetion )2 jo9+ toge!r4 ,convex4 ,a r\nd$ surface2 a bulg+ out4 ,conclusion4 ,! end2 a f9d+ 9 law2 a reason+ f a c]ta9 condition4 ,conductivity4 ,! prop]ty ( mat]ials :]eby !y w transmit heat along f "o "p to ano!r1 also electricity4 ,conc5trat$4 ,br\ght toge!r2 assembl$ 9 a small] space4 ,conclusive4 ,a positive end+2 decisive ( ! matt] at issue4 ,conc5trically4 ,a l9e :i* is at all po9ts at ! same di/ance f "o po9t4 ,cond5sation4 ,! act or process ( mak+ d5s]1 or be+ br\ght toge!r4 ,contemplate4 ,to consid]2 to judge4 ,convoys4 ,a protect+ =ce :i* aeeompanies ! transf] ( prop]ty4 ,convection4 ,! diffusion ( heat ?r\gh a liquid or gas4 ,consi/5t4 ,a /ate ( h>mony2 ! same at #aa times4 ,con/ant4 ,9 ma!matics1 a figure :i* nev] *anges2 or a figure us$ z a fix$ valuation 9 a problem4 ,controllable4 ,held )9 b\nds2 t :i* c be )9 ! p[] to accompli%4 ,correctional4 ,! means :]eby a fault may be made "r4 ,consequ5ce4 ,! result2 t :i* fl[s f a prec$+ action4 ,c\nt]=ce4 ,an action contr>y or opposite to ! ma9 =ce4 ,c\nt]-balance4 ,any p[] equally oppos+ ano!r4 ,c\nt]act4 ,a =ce act+ 9 opposition to ano!r4 ,c\nt]curr5t4 ,an air curr5t :i* sets up 9 an opposite direction 9 ! pa? ( a mov+ a]oplane4 ,cu%ion$4 ,an action :i* takes place aga9/ a mov+ a]oplane1 by a sudd5 gu/ ( air or c\nt]curr5t4 ,d$icat$4 ,to set ap>t = "s special purpose4 ,degree4 ,an int]val2 a grade2 a /age2 a c]ta9 proportion4 ,deltoid4 ,%ap$ l ! ,greek lett] delta4 ,d5sity4 ,clos5ess ( p>ts4 ,demon/ration4 ,mak+ cle>2 %[+ up2 an exhibition or expression4 ,deceptive4 ,! p[] or t5d5cy to give a false impression4 ,det]r5t4 ,to hold back2 to prev5t action4 ,detract+4 ,! t5d5cy to take away2 to belittle4 ,depress$4 ,to move d[nw>dly4 ,de/9ation4 ,! place set = ! end ( ! j\rney4 ,despoil+4 ,to take away f2 robb+ or tak+ f ano!r by =ce or by /eal?4 ,dep5dant4 ,hang+ bel[2 project+ f ! l[] side4 ,dext]ity4 ,agility2 sm>tness 9 action4 ,d]ang$4 ,put out ( ord]2 wrongly arrang$4 ,develop4 ,br\ght out2 to put into a correct %ape or =m4 ,def]r$4 ,put ov] to ano!r "t4 ,design$ly4 ,) a direct purpose4 ,diagonal4 ,across an object at an angle to "o or m aides4 ,diametrically4 ,across an object ?r\gh or ne> ! c5t] !re(4 ,diagram4 ,a me*anical plan or outl9e ( an object4 ,dim5sion4 ,! di/ance across an object4 ,! measurem5t1 = in/ance1 ( a propell] f tip to tip4 ,dynamically4 ,p]ta9+ to motion z a result ( =ce4 ,dispossess$4 ,a t]m us$ to indicate ! act :i* removes a p]son f ! possession ( prop]ty4 ,diamet]4 ,! measurem5t across an object4 ,dive/4 ,tak5 away f2 remov$ out (4 ,disreg>d4 ,delib]ate lack ( att5tion4 ,div]sity4 ,! /ate :]e9 "o is unlike ano!r2 dissimil>ity4 ,drift4 ,! t]m us$ to indicate ! horizontal motion1 or ! pull ( an a]oplane4 ,dragon4 ,a fabul\s mon/]1 usually 9 ! =m ( a s]p5t4 ,duplicate4 ,two2 made 9 exact imitation ( an orig9al4 ,easem5t4 ,a legal phrase to designate t "r :i* man possesses1 irrespective ( any law1 to ga9 access to 8 prop]ty4 ,effront]y4 ,boldness ) insol5ce2 ra%ness )\t propriety4 ,effective4 ,to be effici5t4 ,elem5t4 ,"o "p ( a :ole4 ,ela/icity4 ,mat]ial :i* w g back to its orig9al =m aft] be+ di/ort$1 is said to be ela/ic4 ,elim9ate4 ,to take away f2 to remove a "p1 or ! :ole4 ,elliptical4 ,oblong ) r\nd$ ends4 ,elusive4 ,capable ( escap+ f2 h>d to hold4 ,elevator4 ,! horizontal planes 9 front or re>1 or 9 bo? front & re> ( ! support+ surfaces ( an a]oplane4 ,em]g5cy4 ,a sudd5 occurr5ce call+ = imm$iate action4 ,emplacem5t4 ,a spot design$ to hold heavy field pieces 9 intr5*m5ts4 ,enactm5t4 ,! =mulation ( a law2 ! do+ ( a special ?+4 ,enunciat$4 ,ann\nc$2 sett+ =? ( an act or a condition4 ,en]gy4 ,t quality by reason ( :i* any?+ t5ds to move or act4 ,equidi/ant4 ,two po9ts or objects at equal di/ance f a common po9t4 ,equilibr9m4 ,a balance produc$ by ! action ( two or m =ces4 ,equaliz+1 ,"o made equal to ! o!r2 "o side ! same z ! o!r4 ,equipp$4 ,arm$2 provid$ ) ! prop] mat]ial1 or 9 ! same condition4 ,ess5tial4 ,! important "p or elem5t4 ,ess5ce ,! real *>aet] or elem5t ( ! ?+ itself4 ,ext]nal4 ,! out]mo/ portion4 ,evolution4 ,a gradual *ange or build+ up2 f a l[] to a high] ord]4 ,evolv$4 ,br\ght out f a crude condition to a bett] =m4 ,expression4 ,! art ( expla9+ or sett+ =?4 ,expansion4 ,gr[+ l>g]2 to occupy a great] space4 ,ex]t$4 ,to "w to ! utmo/2 to put =? 9 action4 ,exhil>atiorn4 ,a lively1 pleas+ or happy s5sation4 ,exploit$4 ,to fully exam9e & consid]1 z well z c>ry out4 ,extremity4 ,! end2 z f> z ean be consid]$4 ,facility4 ,ease ( managem5t2 to d ?+s )\t difficulty4 ,factor4 ,"o ( ! elem5ts 9 a problem1 or 9 me*anical action4 ,fasc9ation1 ,attraetiv5ess t is pleas+4 ,flexure4 ,! capacity to b5d & yield1 & return to its orig9al position4 ,flexible1 ,t :i* w yield2 spr+y4 ,=e & ,aft4 ,l5g?wise1 z f /em to /]n ( a %ip4 ,=mation4 ,! %ape or arrangem5t ( an article or ?+4 ,=mulat$4 ,put into "s eon]ete =m1 or s arrang$ t x may be und]/ood4 ,frictionless4 ,be+ )\t a gr9d+ or ret>d+ aotion4 ,fulcrum$4 ,a re/+ place = a lev]4 ,function4 ,! duty or sph]e ( action 9 a p]son1 or object4 ,glid]4 ,an a]oplane1 )\t p[]1 adapt$ to be op]at$ by an aviator4 ,gov]n+4 ,an elem5t :i* is design$ to control a ma*9e 9 a regul> mann]4 ,graduat$4 ,a m>k$ portion1 :i* is regul>ly laid (f to indicate measurem5ts or quantities4 ,gravity4 ,! attraction ( mass = mass4 ,! t5d5cy ( bodies to move t[>d ! e>?4 ,gravitatior ,! =ce ) :i* all bodies attract ea* o!r4 ,gyratory4 ,hav+ a circul> & :eel+ z well z a rot>y motion4 ,gyroscope4 ,a :eel1 design$ to illu/rate ! laws ( motion1 :i* freely revolves 9 gimbals )9 a r+1 & :5 set into motion1 objects to *ange its plane ( rotation4 ,hemisph]ical4 ,! half ( a sph]e4 ,! half ( an apple w\ld be hemisph]ical4 ,haz>d\s4 ,t :i* is d\btful2 accompani$ by dang]4 ,helicopt]4 ,a type ( fly+ ma*9e :i* has a l>ge propell]1 or m ?an "o1 revolubly fix$ on v]tical %afts1 by means ( :i* ! ma*9e is laun*$ & project$ ?r\gh ! air4 ,horizontal4 ,level1 l wat]4 ,hydroplane4 ,a t]m us$ to designate an a]oplane :i* is provid$ ) pontoons1 :]eby x may alight on ! wat]1 & be laun*$ f ! surface4 ,! t]m hydroa]oplane is mo/ g5]ally us$ to indicate ?is type ( ma*9e4 ,impact4 ,! /rik+ aga9/2 ! /rik+ =ce ( "o body aga9/ ano!r4 ,imm]s$4 ,plac$ "u wat] bel[ ! surface4 ,imp+e4 ,to /rike aga9/2 usually appli$ :]e air /rikes a plane or a surface at an angle4 ,imitation4 ,simil>ity2 ! same 9 appe>ance4 ,incompatible4 ,)\t h>mony2 incapable ( exi/+ toge!r4 ,incurv$4 ,appli$ to a surface =mation :]e !re is a depression1 or holl[4 ,inequalities4 ,n smoo?1 or regul>2 unev54 ,inf9itely1 ,b\ndless2 9 great numb]1 or quality2 )\t measure4 ,initial4 ,! fir/2 t :i* is at ! beg9n+4 ,inde/ructibility4 ,n capable ( be+ injur$ or de/roy$4 ,influ5c$4 ,sway$2 to be induc$ to *ange4 ,inh]5t4 ,t :i* is 9 or belongs to itself4 ,initiat+4 ,to tea*2 to in/ill2 to give an insight4 ,indicator4 ,a t]m appli$ to me*anism :i* %[s ! results ( c]ta9 op]ations & enables ! us] to read ! measure1 quantity1 or quality %[n4 ,inconceivable4 ,n capable ( und]/&+2 t :i* _c be und]/ood by ! human m9d4 ,in/itute4 ,to />t2 to br+ into op]ation4 ,insignias4 ,?+s :i* are significant ( any p>ticul> call+ or pr(ession4 ,in/9ct4 ,t quality 9 man or animals :i* prompts ! do+ ( ?+s indep5d5tly ( any direct k or und]/&+4 ,int]m$iate4 ,betwe52 t :i* may be )9 or inside ! scope ( ! m9d1 or ( c]ta9 areas4 ,int]v5+4 ,! "t betwe52 also appli$ to ! action ( a p]son :o may take "p 9 an affair betwe5 two or m p]sons4 ,int]val4 ,a "t betwe54 ,inve/igator4 ,"o :o und]takes to f9d out c]ta9 ?+s4 ,incid5ce4 ,9 physics ?is is a t]m to indicate ! l9e :i* falls ^u or /rikes ano!r at an angle4 ,inv]t$4 ,upside d[n4 ,inve/4 ,to give to ano!r ?+ some?+ t x lack$ be=e4 ,k9etic4 ,consi/+ 9 or dep5d+ ^u motion4 ,lam9at$4 ,made up ( a plurality ( p>ts4 ,:5 wood5 /rips1 ( diff]5t or ( ! same k9ds are glu$ & !n laid toge!r & put "u heavy pressure until ?or\ghly dri$1 ! mass makes a f> m rigid /ructure ?an if cut out ( a s+le piece4 ,laun*iug4 ,! t]m appli$ to ! rais+1 or />t+ ( a boat1 or ( a fly+ object4 ,lat]al4 ,9 m9+ ?is is a t]m to indicate ! drifts or tunnels :i* bran* out f ! ma9 tunnel4 ,g5]ally x has ref]5ce to a transv]se position or direction1--t is1 at "r angles to a =e & aft direction4 ,lift4 ,! v]tical motion1 or direction 9 an air%ip2 ?us ! lift may be ! load1 or ! t]m us$ to designate :at ! %ip is capable ( rais+ up4 ,ligam5t4 ,! exce$+ly /rong t5dons or muscles ( birds & animals1 usually ( firm1 compact tissues4 ,limitations4 ,)9 c]ta9 b\nds2 9 a prescrib$ scope4 ,longitud9ally4 ,usually t direction across ! longe/ "p4 ,maje/ically4 ,gr&2 exalt$ dignity2 ! quality :i* inspires rev]5ce or fe>4 ,manipulate4 ,to h&le2 to conduct s t x w result 9 a c]ta9 way4 ,maneuv]4 ,a me?odical movem5t or *ange 9 troops4 ,manually4 ,to p]=m by h&4 ,manife/ations4 ,! act ( mak+ pla9 to ! eye or to ! und]/&+4 ,manually-op]at$4 ,) ! h&s2 a t]m appli$ to su* ma*9es z h ! control planes op]at$ by h&4 ,ma9ta9$4 ,kept up2 to provide =2 to su/a94 ,mat]ial4 ,! sub/ance1 or ! matt] f :i* an article is made2 also ! important ?+1 or elem5t4 ,mass4 ,9 physics x is t :i* 9 an article is always ! same4 ,x diff]s f weight 9 ! p>ticul> t ! mass ( an article is ! same1 h[ev] f> x may be f ! c5t] ( ! e>?1 :]eas weight *anges1 & becomes less & less z x rec$es f ! c5t] ( ! e>?4 ,m>g94 ,! edge2 ! pr9cipal diff]ecee betwe5 ?is ^w & edge1 is1 t m>g9 has ref]5ce also to a bord]1 or n>r[ /rip along ! edge1 z1 = in/ance1 ! blank spaces at ! edges ( a pr9t$ page4 ,m$ievral4 ,belong+ to ! ,middle ,ages4 ,m]cury4 ,a silv]-:ite liquid metal1 usually call$ quicksilv]1 & r heavy4 ,x dissolves mo/ metals1 & ?is process is call$ amalgamation4 ,militate4 ,9 det]m9+ a "q1 to h weight1 or to influ5ce a decision4 ,mobility4 ,be+ freely movable2 capable ( quick *ange4 ,modifieation4 ,a *ange2 mak+ a diff]5ce4 ,monitor4 ,advis+ or reprov+4 ,advis+ or approv+ by way ( caution4 ,mon/rosities4 ,any?+ :i* is huge1 or di/ort$1 or wrong 9 /ructure4 ,monorail4 ,a railway ) a s+le track1 design$ to be us$ by a bicycle =m ( c>riage1 ) two :eels1 =e & aft ( ea* o!r1 & dep5d+ = its /ability ^u gyroscopes1 m\nt$ on ! c>riage4 ,mom5tum4 ,t :i* makes a mov+ body difficult to /op4 ,x is ! weight ( a mov+ body1 multipli$ by its spe$4 ,monoplane4 ,! lit]al mean+ is "o plane4 ,z monoplane ma*9es are all provid$ ) a =e & aft body1 & ea* has a w+ or plane project+ out f ea* side ( ?is body1 x is obvi\s t x has two planes in/ead ( "o4 ,! t]m1 h[ev]1 has ref]5ce to ! fact t x has only "o support+ surface on ! same plane4 ,biplanes h two support+ surfaces1 "o above ! o!r4 ,multiplicity4 ,frequ5tly conf\nd$ ) plurality4 ,! latt] means m ?an "o1 :]eas multiplicity has ref]5ce to a great numb]1 or to a great v>iety4 ,muscul>4 ,be+ /rong2 well develop$4 ,negative4 ,! opposite ( positive2 n decisive4 ,neutralize4 ,f ! ^w neut]1 :i* means nei!r1 h5ce ! t]m may be def9$ z "o :i* is n a "p ( ei!r1 or does n take up ) ei!r side4 ,normal ,pressure4 ,normal means ! natural or usual1 & :5 appli$ to air x w\ld h ref]5ce to ! condition ( ! atmosph]e at t p>ticul> place4 ,if ! pressure c\ld *ange f its usual condition1 x w\ld be an abnormal pressure4 ,notori\sly4 ,g5]ally kn[n1 b n favorably s2 ! subject ( g5]al rem>k2 or unfavorably kn[n4 ,obscurity4 ,n well kn[n2 9 ! backgr\nd2 )\t cle> vision2 hidd5 f view4 ,obliquely4 ,t :i* diff]s f a "r angle2 nei!r obtuse nor acute2 deviat+ f a l9e by any angle except a "r angle4 ,obvi\s4 ,t :i* is readily obs]v$ & und]/ood4 ,or?opt]4 ,t type ( fly+ ma*9e :i* dep5ds on flapp+ w+s to hold x 9 space1 & to transport x1 9 imitation ( ! motion ( ! w+s ( birds 9 fly+4 ,oscillate4 ,mov+ to & fro2 ! pi/on ( a /eam eng9e has an oscillat+ motion4 ,outl9e4 ,describ+ a m>g9al l9e on a draw+2 sett+ =? ! pr9cipal features ( an argum5t1 or ! details ( a /ory1 or ! l4 ,ov]lapp+4 ,"o plac$ ov] ! o!r4 ,p>abolic4 ,a =m ( curve some:at simil> to an ellipse4 ,p$e/al4 ,a /&>d or support2 an upright to hold ma*9]y4 ,p]t95t4 ,appropriate2 p]ta9+ to ! subject4 ,pectoral4 ,! bone :i* =ms ! ma9 rib or support at ! =w>d edge ( a bird's w+4 ,p]si/5t4 ,keep+ at x2 det]m9ation to proce$4 ,p]p5dicul>4 ,at "r angles to a surface4 ,?is t]m is sometimes wrongly appli$ 9 ref]r+ to an object1 p>ticul>ly to an object :i* is v]tical1 mean+ up & d[n4 ,! blade ( a squ>e is p]p5dieul> to ! h&le at all times1 b ! blade is v]tical only :5 x po9ts to ! c5t] ( ! e>?4 ,p]nici\s4 ,bad2 n hav+ good features or possess+ wrong attributes4 ,p5dulum4 ,a b> or body susp5d$ at a po9t & adapt$ to sw+ to & fro4 ,p]petual4 ,= all "t2 un5d+ or unlimit$ "t4 ,ph5om5a4 ,"s peculi> happ5+1 or ev5t1 or object4 ,pit*4 ,9 aviation ?is applies to ! angle at :i* ! blades ( a propell] are cut4 ,if a propell] is turn$1 & x moves =w>dly 9 ! exact pa? made by ! angle1 = "o complete turn1 ! di/ance travel$ by ! propell] axially indicates ! pit* 9 feet4 ,placem5t4 ,:5 an object is locat$ at any p>ticul> po9t1 s t x is op]ative ! location is call$ ! placem5t4 ,plane4 ,a flat surface = support+ a fly+ ma*9e 9 ! air4 ,plane ( movem5t p]ta9s to ! imag9>y surface describ$ by a mov+ body4 ,a bicycle :eel1 = in/ance1 :5 mov+ =w>dly 9 a /raight l9e1 has a plane ( movem5t :i* is v]tical2 b :5 ! ma*9e turns 9 a circle ! upp] end ( ! :eel is turn$ inw>dly1 & ! plane ( rhovem5t is at an angle4 ,pliant4 ,easily yield+2 capable ( be+ b5t2 liable to be put out ( %ape4 ,plurality4 ,see multiplicity4 ,m ?an "o4 ,poise4 ,held 9 susp5sion2 dispos$ 9 a p>ticul> way4 ,pontoon4 ,appli$ to a s]ies ( boats rang$ side by side to support a walk laid !reon4 ,9 aviation x has ref]5ce to a float = support+ an a]oplane4 ,pond]\s4 ,l>ge2 heavy2 difficult to h&le4 ,po/]ior4 ,! re> end2 ! opposite ( ant]ior4 ,pr9ciples4 ,! v nature or ess5ce ( a ?+2 ! s\rce or cause f :i* a ?+ spr+s4 ,proportion4 ,! relation t exi/s betwe5 diff]5t p>ts or ?+s4 ,prop\nd$4 ,que/ion$2 /at$2 to /ate =mally = consid]ation ,propriet>y4 ,a "r2 ! own]%ip ( c]ta9 prop]ty4 ,primitive4 ,! beg9n+ or e>ly times2 long ago4 ,prelude4 ,a /atem5t or action :i* prec$es ! ma9 feature to be pres5t$4 ,proximity4 ,close to2 ne> at h&4 ,prototype4 ,t :i* is us$ z ! sample f1 :i* some?+ is made or judg$4 ,propell]4 ,! piece ( meebanism1 ) screw %ap$ blade1 design$ to be rapidly rotat$ 9 ord] to drive a vessel =w>dly4 ,x is claim$ by "s t ! ^w ,impell] w\ld be ! m prop] t]m4 ,prim>ily4 ,at ! fir/2 ! comm5cem5t4 ,prec$es4 ,goes ahead2 =w>d ( all4 ,propulsive4 ,! =ce :i* gives motion to an object4 ,project$4 ,?r[n =w>d2 caus$ to fly ?r\gh ! air4 ,radially4 ,out f ! c5t]2 project+ l ! spokes ( a :eel4 ,ratio4 ,! relation ( degree1 numb]1 am\nt2 "o ) ano!r4 ,reaction4 ,a c\nt]=ce2 act+ aga9/4 ,recognize4 ,to "k2 see+1 he>+1 or feel+1 & hav+ k !refrom4 ,reflection4 ,consid]+2 judg+ "o ?+ by ! exam9ation ( ano!r4 ,a beam ( light1 or an object1 leav+ a surface4 ,refraction4 ,t peculi>ity 9 a beam ( light1 :i*1 9 pass+ ?r\gh wat] at an angle1 b5ds out ( its c\rse & aga9 assumes a direct l9e aft] pass+ ?r\gh4 ,reflex4 ,turn$ back on itself1 or 9 ! direction f :i* x came4 ,requisite4 ,en\gh2 suffiei5t = all purposes4 ,relegate4 ,to put back or away4 ,rectangul>4 ,hav+ "o or m "r angles4 ,res]vations4 ,l& :i* is held by ! ,gov]nm5t = v>i\s purposes4 ,resi/ance4 ,t :i* holds back2 prev5t+ movem5t4 ,ret>d+4 ,prev5t+ a free movem5t4 ,revoluble4 ,! turn+ or sw++ motion ( a body l ! e>? 9 its movem5t ar\nd ! sun4 ,see ,rotative4 ,to cause to move z 9 an orbit or circle4 ,resili5t4 ,spr+y2 hav+ ! quality ( ela/icity4 ,rev]s$4 ,*ang$ ab\t2 turn$ front side to ! re>4 ,rotative4 ,t :i* turns1 l a %aft4 ,! movem5t ( ! e>? on its axis is rotative4 ,saturation4 ,putt+ "o sub/ance into ano!r until x w hold no m4 ,= in/ance1 add+ salt to wat] until ! wat] _c take up any m4 ,security4 ,safety1 assur$ness t !re w be no dang]4 ,segm5t4 ,a "p eut (f f a circle4 ,di/+ui%$ f a sector1 :i* might be lik5$ to ! =m ( "o ( ! sections ( an orange4 ,sexagonal4 ,six-sid$4 ,s9e ( ! ,angle4 ,! l9e dropp$ f ! highe/ po9t ( an angle to ! l9e :i* runs out horizontally4 ,s9u\s4 ,wavelike2 mov+ up & d[n l ! waves ( ! ocean4 ,simulates4 ,to patt]n or copy aft]2 ! mak+ ( ! l4 ,skipp]4 ,a ?9 flat /one4 ,spirally-=m$4 ,made l an aug]2 twi/$4 ,/ability4 ,9 air%ips t quality :i* holds ! %ip on an ev5 & unsw]v+ c\rse1 & prev5ts plung+ & side motions4 ,/ructural4 ,belong+ to ! features ( eon/ruetion4 ,/rata4 ,two or m lay]s2 "o ov] or bel[ ! o!r4 ,/ream l9e4 ,9 express+ ! action ( mov+ air1 or an a]oplane transport$ ?r\gh air1 e "p is act$ ^u by ! air4 ,/ream l9es are imag9>y l9es :i* act ^u ! planes at all po9ts1 & all 9 ! same direction1 or angle4 ,/up5d\s4 ,great2 important2 above ! ord9>y4 ,sub/itute4 ,"o tak5 = ano!r2 replac+ "o ?+ by some?+ else4 ,support+4 ,giv+ aid2 help+ ano!r4 ,syn*ron\s4 ,act+ at ! same "t1 & to ! same ext5t4 ,?us if two :eels1 sep>at$ f ea* o!r at great di/ances1 are s arrang$ t !y turn at exactly ! same spe$1 !y are said to turn syn*ron\sly4 ,tactics4 ,! art ( h&l+ troops 9 ! pres5ce ( an enemy4 ,x diff]s f /rategy 9 ! p>ticul> t ! latt] ^w is us$ to expla9 ! movem5ts or arrangem5t ( =ces be=e !y arrive at ! battle l9e4 ,t&em4 ,"o be=e ! o!r2 "o aft] ! o!r4 ,tang5t4 ,a l9e drawn f a circle at an angle1 in/ead ( radially4 ,te*nically4 ,p]ta9+ to "s p>ticul> trade1 sci5ce or art4 ,t5u\s4 ,?91 sl5d]1 will[y1 slight4 ,tetrah$ral4 ,?is has ref]5ce to a =m :i* is made up ( a multiplicity ( triangul>ly %ap$ ?9 blades1 s z to =m num]\s cells1 & ?us make a l>ge numb] ( support+ surfaces4 ,us$ z a kite4 ,!ories4 ,views bas$ ^u c]ta9 consid]ation4 ,!oretical4 ,:]e op9ions are f\nd$ on c]ta9 in=mation1 & express$1 n f ! /&po9t ( actual k1 b ^u conclusions d]iv$ f su* exam9ations4 ,torsion4 ,a twi/2 a circul> motion ar\nd a body4 ,transmitt$4 ,s5t out2 convey$ f "o po9t to ano!r4 ,trans=m$4 ,*ang$2 entirely made ov] f "o ?+ to ano!r4 ,transv]se4 ,:5 a body is %ort] f front to re> ?an f side to side its longe/ dim5sion is transv]sely4 ,di/+ui% f lat]al1 :i* has ref]5ce only to ! di/ance at "r angles f ! ma9 body4 ,translation4 ,! transportation ( a body ?r\gh ! air4 ,trajectory4 ,! pa? made by a body project$ ?r\gh ! air4 ,triangul>4 ,a =m or body hav+ ?ree sides & ?ree angles4 ,typical4 ,9 ! =m (2 a lik5ess to4 ,ultimate4 ,! end2 ! f9ality2 ! la/ t c be said4 ,un9itiat$4 ,n hav+ full k2 )ont in=mation4 ,unique4 ,peculi>2 some?+ t on acc\nt ( its peculi> con/ruction or arrangem5ts /&s out beyond ! o!rs4 ,univ]sal4 ,ev]y:]e2 all ov] ! _w4 ,undulate4 ,to move up & d[n2 a wave-l motion4 ,utility4 ,( use2 to take advantage\s use (4 ,un/able4 ,n hav+ any?+ p]man5t2 9 a %ip 9 flight "o t w n ride on an ev5 keel1 & is liable to pit* ab\t4 ,vacuum4 ,:]e air is p>tly tak5 away1 or r5d]$ r>]4 ,valv$4 ,a surface :i* has a multiplicity ( op5+s ) valves !re91 or1 ?r\gh :i* air c move 9 "o direction4 ,vaunt$4 ,to boa/ conc]n+2 to give a high op9ion4 ,velocity4 ,spe$2 ! rate at :i* an object c move f place to place4 ,v]tical4 ,a l9e runn+ directly to ! c5t] ( ! e>?2 a l9e at "r angles to ! surface ( wat]4 ,vibratory4 ,mov+ f side to side2 a regul> motion4 ,volplane4 ,! glide ( a ma*9e )\t ! use ( p[]4 ,w>p+4 ,! twi/ giv5 to c]ta9 portions ( planes1 s z to cause ! air to aet aga9/ ! w>p$ portions4 ,weight4 ,! measure ( ! =ce :i* gravity ex]ts on all objects4