,,natural ,,/ability ,,& ,,! ,,p>a*ute ,,pr9ciple ,,9 ,,a]oplanes ,,by ,w4 ,,lemaitre ,hon4 ,sec41 ,a]oplane ,build+ & ,fly+ ,society ,,) #cd ,,illu/rations ,,london ,e4 ,f4 ,n4 ,,spon1 ,,ltd41 #eg ,,haym>ket ,new ,york ,,spon ,,*amb]la91 #abc ,,lib]ty ,,/reet #aiaa ,,cont5ts ,,page ,,frontispiece iv ,,preface ix ,,*apt] ,i4 ,,! ,,importance ,,( ,,/ability #aa ,,ii4 ,,spe$ ,,z ,a ,,means ,,( ,,/ability #ad ,,iii4 ,,! ,,l[ ,,c5tre ,,( ,,gravity #ag ,,iv4 ,,%ort ,,span ,,& ,,area #bh ,v4 ,,v>iable ,,spe$ ,,& ,,! ,,p>a*ute ,,pr9ciple #cf ,,vi4 ,,! ,,design ,,:i* ,,fulfils ,,! ,,conditions #ci ,,preface ,s9ce !re is no?+ new "u ! sun1 x is useless to pret5d t !re is any?+ new 9 ! design "h advocat$ or ! !ories advanc$4 ,bo? are r ! result ( a commons5se consid]ation ( ! diff]5t po9ts ( all fly+ ma*9es1 natural & artificial1 & an endeav\r to select f ! great numb] ( good po9ts ^? :i* seem mo/ likely to bl5d toge!r into a practical ma*9e4 ,! conclusions rea*$ are ! result ( a q indep5d5t inve/igation1 c>ri$ on ov] ?ree ye>s by means ( numb]less exp]im5ts1 & ! writ] has endeav\r$ to make no s+le /atem5t :i* he _c by "s exp]im5t amply prove4 ,,natural ,,/ability ,,9 ,,a]oplanes ,,*apt] ,i4 ,,! ,,importance ,,( ,,/ability4 ,9 consid]+ ! :ole "q ( aviation1 x becomes evid5t t ! "o po9t to /rive = at ! pres5t juncture is /ability4 ,if we are ev] to h a practical fly+ ma*9e1 t is1 a ma*9e :i* we c use z we d a ya*t1 a motor c>1 or a bicycle1 x mu/ be "o t we c tru/ to keep its balance by reason ( ! natural =ces embodi$ 9 x1 & )\t any ef=t ( control on ! "p ( ! pilot4 ,x may be object$ t a bicycle does n d ?is1 & ?is is true1 b1 on ! o!r h&1 ! upsett+ ( a bicycle is a v small matt]1 :]eas ! tilt+ ( an a]oplane mo/ly means sudd5 dea? to its occupant1 & x is probable t if ! same consequ5ces foll[$ ! tilt+ ( a bicycle1 bicycles w\ld soon h be5 made ) f\r :eels4 ,at pres5t a]oplanes are ! mo/ un/able ( all ?+s4 ,! lea/ gu/1 ! lea/ %ift+ ( weight1 ! slighte/ diff]5ce 9 ! d5sity ( ! /rata ( ! support+ air1 & ! ma*9e sways1 & if n in/antly correct$ by ! pilot ! sway becomes a tilt1 ! tilt a dive1 & ! re/ is sil5ce4 ,! fir/ a]oplanes1 ! ,wrights' = in/ance1 7 s un/able t tw5ty m9utes 9 "o ( !m 0 z mu* z ! mo/ iron-n]v$ man c\ld /&1 ! cont9ual /ra9 be+ too exhau/+ to keep up = any l5g? ( "t4 ,by ?r[+ out ext5sions & outrigg]s 9 all directions we h alt]$ t to a c]ta9 ext5t1 b only to an ext5t--we h n yet got rid ( x4 ,! monoplane is probably ! mo/ un/able1 z might be expect$ f its small] surface1 b ! bi-plane runs x pretty closely4 ,& ! difficulty seems to arise *iefly f ! fact t ! ma*9es are built r\nd ! propell]4 ,9 ! case ( a ya*t or a c>1 ! ma*9e is built fir/ & ! propell+ means is fitt$ on z an auxili>y4 ,! consequ5ce is t an a]oplane :i* is safe en\gh :ile ! propell] is ex]t+ a tractive =ce ( "s #bej lbs41 becomes1 ! mom5t ?is p[] is = any reason /opp$1 m]ely a %apeless con/ruction at ! m]cy ( ! w9d & ! =ce ( gravitation4 ,x is true t mo/ ma*9es may be made to glide if ! pilot is clev] en\gh & quick en\gh to /e] !m into ! prop] glid+ angle1 b ! ma*9e t w naturally & by reason ( its design assume its prop] glid+ angle :5 ! propell+ =ce is )drawn1 has n yet be5 built4 ,su* a ma*9e w\ld h 8,natural ,/ability40 ,x w be recogniz$ t ?is natural /ability1 :i* dep5ds on ! design ( ! ma*9e1 is some?+ entirely diff]5t f 8automatic /ability0 ( :i* !re are _m sy/ems1 all hav+ ?is "o defect2 t1 dep5d+ ^u work+ devices1 movable planes1 gyroscopes1 comp5sat+ balanc]s1 p5dulums1 etc41 !y are all liable to g wrong & refuse to act ! mom5t a sudd5 /ra9 makes _! p]fect action mo/ important4 ,consid]+ t ! propell] is ! only means ! a]oplane has ( keep+ 9 ! air at all1 ! "q arises3 ,is x possible to design a ma*9e t w be /able to ! ext5t ( desc5d+ safely :5 ! propell] /ops1 & t w yet be a good & spe$y fly]8 ,t is ! problem we h to solve4 ,,*apt] ,,ii4 ,,spe$ ,,z ,a ,,means ,,( ,,/ability4 ,x is recogniz$ on all h&s t spe$ is a great factor 9 ! problem ( /ability4 ,to beg9 )1 a ma*9e go+ at high spe$ w\ld be practically unt\*$ by gu/s ( w9d1 diff]5t d5sities ( air /rata1 holes 9 ! air1 etc4 ,also its great] mom5tum w\ld t5d to keep x 9 a /raight l9e1 n only relative to its c\rse b also relative to itself4 ,t is to say1 its w+s be+ />t$ 9 a horizontal plane1 w\ld t5d to keep 9 ! same plane & w\ld n easily tilt or sway out ( x4 ,bo? ^! effects ( natural law %[ t a high spe$ ma*9e mu/ be m /able ?an a l[ spe$ ma*9e4 ,h[ !n are we to design a high spe$ ma*9e8 ,leav+ aside ! "q ( high] p[]1 ! fir/ po9t t sugge/s itself is to less5 ! head resi/ance4 ,all fa/ ?+s1 boats1 birds1 arr[s1 ev5 motor-c>s1 are made long & n>r[4 ,x w be object$ t a bird ) its w+s outspread is n long & n>r[1 b 9 ! s5se 9 :i* ?is illu/ration is meant1 ! bird's w+s1 be+ m]ely its propell+ app>atus1 d n c\nt1 & :5 ! bird is at its fa/e/1 z 9 ! swoop ( a hawk or an eagle1 ! w+s are %ut tightly to ! body s z to (f] no resi/ance to its lightn+ passage ?r\gh ! air4 ,if we are to foll[ previ\s exp]i5ce 9 ,nature's laws1 our a]oplanes mu/ be consid]ably r$uc$ 9 span4 ,to drive ?r\gh ! air at a high spe$ ) a ma*9e ( #dj foot span is a practical impossibility1 bo? because ( ! trem5d\s p[] x w\ld require & also by reason ( ! great /r5g? ! plane mu/ h to )/& ! resi/ance ( ! air4 ,9 r$uc+ ! span1 h[ev]1 we r$uce ! lift+ surface ( ! ma*9e4 ,b on ! o!r h& x mu/ be rememb]$ t ! lift+ effici5cy is increas$ by increas+ ! spe$4 ,lift is ! product ( support+ surface & spe$4 ,a small plane driv5 at a high spe$ w give z great a lift z a l>ge plane driv5 at a l[ spe$4 ,spe$1 aga91 is ! diff]5ce betwe5 ! propell+ p[] & ! head resi/ance1 & we c increase ! spe$ by decreas+ ! resi/ance4 ,x foll[s1 !n1 t we ne$ n necess>ily give up lift+ p[] by r$uc+ ! span ( ! w+s1 s9ce ! %ort] span gives great] spe$1 & ! increase ( effici5cy by reason ( ! great] spe$ w\ld g to make up = ! loss ( span4 ,x is1 !n1 q possible to design a %ort span ma*9e :i* %all be z effici5t = lift z a long span ma*9e1 & :i* w h ! advantage ( possess+1 by reason ( its spe$1 mu* great] /ability4 ,b ! span is n ! only factor 9 ! spe$ problem4 ,9 ! l[ spe$ ma*9es at pres5t 9 use we h f\nd x necess>y to curve ! planes to get great] effici5cy4 ,?is effici5cy is also ga9$ at ! exp5se ( head resi/ance1 & x is already recogniz$ t ! high] ! spe$ ! less is ! ne$ ( camb]4 ,?is is ! same problem ov] aga94 ,a high spe$ flat plane w give z mu* lift z a l[ spe$ camb]$ plane1 & we ga9 9 /ability ) e additional mile p] h\r4 ,! ?ird po9t to be consid]$ 9 ! problem ( spe$ is ! resi/ance caus$ by ! multitude ( /ruts & wires1 ! body ( ! pilot1 ! tanks1 eng9e1 & all ! o!r imp$im5ta project+ 9 all directions f ! body ( ! a]oplane4 ,x has occurr$ to our build]s t if ! :ole ( ^! ?+s c\ld be collect$ toge!r & enclos$ 9 a light cov]$-9 c> ( a prop] %ape1 ! sk9 friction ( su* a c> w\ld be mu* less ?an ! total head resi/ance (f]$ by ! diff]5t ob/ructions s cov]$4 ,& !re is ano!r advantage to be ga9$ "h1 = if1 at #dj miles p] h\r1 ! =ce ( ! w9d is v s]i\sly uncom=table = ! pilot1 ! position at su* spe$s z #gj or #ajj miles p] h\r w\ld be q impossible4 ,,*apt] ,,iii4 ,,! ,,l[ ,,c5tre ,,( ,,gravity4 ,! fir/ ?+ t occurs to ! inve/igator on ! subject ( /ability is t nature (f]s u a sure means ( keep+ our ma*9es upright by adopt+ ! simple me?od ( plac+ all ! heavi] p>ts at ! bottom4 ,9 all o!r con/ructions we h adopt$ ?is plan ) p]fect success4 ,9 boats1 ya*ts1 c>s1 balloons1 ev]y?+ man uses 9 fact1 ! simple/1 be/ & mo/ obvi\s me?od ( keep+ a ?+ upright is to utilize ! =ce ( gravity1 place ! light] or support+ p>ts above & ! weight bel[1 & ! ?+ is done4 ,?is simple me?od ( obta9+ /ability did n escape ! a]oplane design]s1 & we h _h sev]al ma*9es :i* embodi$ ?is pr9ciple1 m or less4 ,un=tunately1 h[ev]1 !y all prov$ failures4 ,a ma*9e w\ld be design$1 &1 ) ! weight high1 w\ld fly well1 ?\gh x 0 un/able4 ,put ! weight l[ & y got rid ( ! in/ability1 & at ! same "t ! ma*9e became unmanageable4 ,x look$ z if fly+ & in/ability 7 int]*angeable t]ms4 ,s1 z x 0 a ma*9e t w\ld fly ! design]s 7 aft]1 ! weight 0 kept up & ! /ability 0 left to ! pilot4 ,! ma*9es 7 made 8s5sitive0 z x is call$1 t is to say1 s5sitive to a t\* ( ! rudd] or ! balanc]s4 ,!y are also1 x is true1 equally s5sitive to a gu/ ( w9d or a slight %ift+ ( weight or pressure1 & ?is has caus$ ! sma%+ ( a good _m ma*9es & "s pilots2 b aft] all ?is is ! =tune ( w>1 & no "o is compell$ to g up 9 an a]oplane4 ,! curi\s ?+ ab\t x is t x does n seem to h occurr$ to our design]s t if _! pet design w\ld n fly ) ! weight l[1 p]haps x might be possible to alt] ! design in/ead ( alt]+ ! position ( ! c5tre ( gravity1 & s obta9 :at we are all look+ =1 a naturally /able ma*9e t is yet s5sitive to control4 ,!re are two *ief difficulties 9 ! way ( ! l[ c5tre ( gravity ma*9e4 ,"o is t ! heavie/ portion ( ! ma*9e be+ "s di/ance bel[ its support1 x is apt to give rise to a p5dulum or sway+ motion4 ,! o!r is t ( tilt+1 or bank+ up1 9 turn+ a corn]4 ,^! are really two developm5ts ( ! same difficulty1 i4e4 p5dulum motion4 ,if we take a /rip ( /iff pap] to repres5t a plane & put a small weight 9 ! c5tre ( ! plane1 ! model on be+ glid$ to e>? does n t5d to sway 7,fig4 #a74 ,if we put our weight on a t9y piece ( wire an in* or s bel[ ! plane 7,fig4 #b7 & set ! model free1 x w probably acquire a sw++ motion z x desc5ds4 ,t is ! :ole tr\ble4 ,! tr\ble is real en\gh1 b ! fallacy is 9 suppos+ x to be all ! fault ( ! l[ c5tre ( gravity4 ,all %ips t 7 ev] design$ h a l[ c5tre ( gravity1 yet "s roll dreadfully & o!rs d n1 :i*1 9 itself1 %\ld be pro( suffici5t t x is ! design ( ! ma*9e & n ! position ( ! balla/ t is at fault4 ,illu/ration3 ,,fig4 #a41 ,,fig4 #b4 ,,& ,,fig4 #c4 ,let u n[ try "s exp]im5ts4 ,x w be notic$ t 9 ! ma*9es :i* h employ$ ! l[ c5tre ( gravity ! span ( ! w+s has usually be5 #cj feet or m1 & ! c5tre ( gravity ab\t #f feet bel[ ! c5tre4 ,"h is a pap] model ( ! pres5t a]oplane 7,fig4 #a74 ,"h is ! same ma*9e ) a l[ c5tre ( gravity 7,fig4 #b74 ,n[ b5d ! pap] upw>ds z 9 ,fig4 #c & y get rid ( ! sway+4 ,also1 ( c\rse1 y get rid ( ! support+ surface4 ,b !re is probably "s po9t ( greate/ effici5cy :]e y may compromise4 ,if y take model #b & b5d x slightly 7,fig4 #d7 x w sway1 b n mu*1 n s mu* z ,fig4 #b4 ,n[ ) a pair ( scissors clip ! w+s a bit at a "t1 & y w f9d t z ! span gets %ort] ! sway+ decreases1 & t :5 y h ! ?ree po9ts =m$ by ! ends ( ! two w+s & ! weight equidi/ant f ! c5tre :]e !y meet1 ! plane is /able 7,fig4 #e74 ,! reason is t x is n ! p5dulum ) ! weight at ! bottom t sw+s s mu*1 b ! long w+s t see-saw4 ,by %ort5+ ! w+s y h r$uc$ ! l5g? ( ! see-saw1 :i* is ! same z r$uc+ ! l5g? ( ! p5dulum1 & consequ5tly1 by p5dulum law1 ! oscillations mu/ be mu* quick] & %ort] & w at once damp out4 ,x is curi\s t ?is po9t seems to h escap$ ! design]s4 ,x is well kn[n t all p5dulum motion t5ds to damp out1 & ! %ort] ! p5dulum ! quick] x comes to re/4 ,hi!rto ! idea has be5 to %ort5 x v]tically1 b ! same effect exactly is obta9$ by %ort5+ x horizontally1 & ! l[ c5tre ( gravity rema9s to give /ability4 ,x 0 /at$ by "s sapi5t objector to ! l[ c5tre ( gravity1 t ! p5dulum motion once set up1 increas$ till x turn$ ! ma*9e ov]4 ,a p5dulum :i* increas$ its sw+ at e /roke w\ld be some?+ new 9 ! sci5tific _w4 ,illu/ration3 ,,fig4 #d4 ,illu/ration3 ,,fig4 #e4 ,ano!r developm5t ( ! p5dulum difficulty is ! probable =e & aft sway1 b ?is may be ov]come by increas+ ! support+ surface ( ! tail4 ,_m ma*9es d n lift ) ! tail at all1 & ^? t d employ lift+ tails1 h !m ) v small surface4 ,consequ5tly1 ! c5tre ( gravity comes ne>ly "u ! c5tre ( ! ma9 plane1 & ! :ole ma*9e1 turn+ on its c5tre ( gravity 9 all directions z on a pivot1 is liable to sw+ =e & aft4 ,if ! support+ surface ( ! tail be increas$ & ! c5tre ( gravity c>ri$ fur!r aft1 ?is p5dulum motion is also r5d]$ impossible1 & ! ma*9e is /able bo? ways4 ,a few illu/rations may s]ve to make ! advantages ( ! l[ c5tre ( gravity m cle>1 & to avoid complications we w suppose ! planes to be /ill & 9 /ill air4 ,let ,fig4 #f repres5t an ord9>y flat plane hav+ its c5tre ( gravity co9cid5t ) its c5tre ( pressure1 ! c5tre ( pressure ( ea* half or w+ be+ at ,a ,a4 ,! plane is 9 equilibrium4 ,n[ all[ x to tilt 7,fig4 #g71 & x w be se5 t x is /ill 9 equilibrium1 s9ce ! weight is 9 ! c5tre & ! w+ tips equidi/ant f x4 ,let x tilt /ill m till x is v]tical 7,fig4 #h71 & ! balance is /ill ! same4 ,x is evid5t1 !re=e1 t su* a plane w\ld travel equally well 9 any ( ! positions %[n1 & t x c only be kept 9 position 7,fig4 #f7 by ! skilful manipulation ( ! pilot4 ,illu/ration3 ,,fig4 #f41 ,,fig4 #g41 ,,& ,,fig4 #h4 ,9 ! same way1 ! ma*9e hav+ no lift+ tail is longitud9ally un/able1 =1 be+ balanc$ on its c5tre ( pressure :i* w\ld be co9cid5t ) its c5tre ( gravity & probably ab\t #b feet f ! trail+ edge ( ! plane--x may assume any position 7,figs4 #i1 #aj1 #aa & #ab71 & /ill be 9 equilibrium1 :5 x is evid5t t ! prop] position 7,fig4 #i7 is only ma9ta9$ by ! con/ant control ( ! tail elevator4 ,illu/ration3 ,,fig4 #i41 ,,fig4 #aj41 ,,fig4 #aa41 ,,fig4 #ab41 ,,& ,,fig4 #ac4 ,n[ take ! case ( a ma*9e hav+ a l[ c5tre ( gravity4 ,its natural position is %[n at ,fig4 #ac1 & x is at once evid5t t any o!r position su* z ,figs4 #ad & #ae c\ld n be ma9ta9$ = a mom5t1 s9ce ! weight be+ at an angle1 mu/ inevitably drag ! ma*9e back to its natural position 7,fig4 #ac74 ,9 ! same way ) reg>d to longitud9al balance1 a ma*9e ) two lift+ surfaces su* z ,fig4 #ac1 is 9 its natural position ) ! c5tre ( gravity p]p5dicul>ly "u ! c5tre ( pressure1 any o!r position1 su* z ,fig4 #ag1 ,a1 is impossible1 z ! gravity pull mu/ drag ! ma*9e along ! dott$ l9e till x resumes its prop] & natural position 7,b74 ,illu/ration3 ,,fig4 #ad41 ,,fig4 #ae41 ,,& ,,fig4 #af4 ,! next difficulty is 9 ! bank+ or tilt+ caus$ by ! turn+ ( ! ma*9e 9 go+ r\nd a curve4 ,9 a v int]e/+ discussion c>ri$ on 9 ! 8,a]o10 x 0 /at$ t a l[ c5tre ( gravity ma*9e c\ld n bank up1 z ! pull ( gravity act+ on ! l[ weight w\ld prev5t x4 ,x 0 also /at$ by ano!r writ] t ! ma*9e w\ld bank up too mu* & slide d[n sideways1 because ! greate/ weight hav+ ! greate/ mom5tum w\ld sw+ out too mu*4 ,!re is evid5tly "s confusion "h4 ,let u consid] ! "q4 ,9 turn+ !re are ?ree =ces to take into consid]ation3 7#a7 ,! c5trifugal =ce1 :i* t5ds to make ! ma*9e fly (f at a tang5t to ! curve at :i* x is turn+4 7#b7 ,! action ( gravitation4 7#c7 ,! extra lift giv5 by ! w+ on ! outside ( ! curve1 ow+ to ! fact t x travels fa/] ?r\gh ! air4 ,illu/ration3 ,,fig4 #ag4 ,! c5trifugal =ce acts /rictly 9 proportion to ! mass x acts on1 b1 at ! same "t x mu/ be rememb]$ t ! great] =ce act+ on ! great] mass has ! great] mass to move4 ,t is to say1 t if ! top "p ( ! ma*9e 0 v light & ! bottom "p v heavy1 ! =ce act+ on ! light "p w\ld be suffici5t to s5d t "p sw++ out :5 r\nd+ a curve1 & ! great] =ce act+ on ! great] mass at ! bottom w\ld be suffici5t to s5d t out to exactly ! same degree4 ,consequ5tly1 if only c5trifugal =ce is consid]$1 ! :ole ma*9e w\ld sw+ out )\t any tilt+ at all1 reta9+ its upright position4 ,b "h we mu/ take ano!r factor into consid]ation1 ! resi/ance ( ! air4 ,?is resi/ance w\ld be great] on ! great] surface ( ! light top "p ?an on ! heavy bottom "p1 & consequ5tly ! bottom "p w\ld1 automatically1 sw+ out mo/1 giv+ ! bank+ effect4 ,?is w\ld be increas$ by ! extra lift giv5 to ! out] w+ by reason ( its great] spe$4 ,if we !n take ! =ce ( gravitation into ! problem we %all see t we h two factors--unequal spe$ & unequal air resi/ance--t5d+ to bank up ! ma*9e1 & "o =ce--gravity--t5d+ to pull x /raight aga94 ,at a c]ta9 angle due to ! am\nt ( =ce ex]t$ by ea* ( ^!1 ! two oppos+ factors w\ld balance1 & ! ma*9e w\ld be 9 equilibrium4 ,x w\ld appe> t mo/ ( ! difficulties connect$ ) ! l[ c5tre ( gravity ma*9e are ! result ( hazy ?9k+ & slip-%od reason+1 & t !y d n exi/ 9 fact4 ,& let x be rememb]$ t ! l[ c5tre ( gravity ma*9e ) %ort span has n yet be5 tri$ except by ! writ]1 :o has succe$$ 9 mak+ a pap] model on ?is plan turn 9 its own l5g? )\t 9 any way los+ its /ability1 sway+1 bank+ too mu*1 turn+ ov]1 slid+ sideways1 or do+ any ( ! frightful ?+s :i* "s p decl>e x mu/ d4 ,:at x does d is to recov] its balance ?\gh />t$ f ! mo/ impossible positions & always l& on its feet4 ,,*apt] ,,iv4 ,,%ort ,,span ,,& ,,area4 ,bo? on acc\nt ( spe$1 & also on acc\nt ( /ability1 ) a l[ c5tre ( gravity1 we are =c$ 9 ! direction ( ! %ort span ma*9e4 ,h[ are we to con/ruct a ma*9e ) a span %ort en\gh to damp out sway+ & yet ) suffici5t lift+ surface to raise ! ma*9e & its load8 ,! position is some:at simplifi$1 z already po9t$ out1 by ! fact t ?\gh ! lift is decreas$ by ! decrease 9 span1 x is to a great ext5t comp5sat$ by ! increase 9 spe$4 ,also ano!r comp5sation is (f]$ by ! fact t =e & aft /ability requires a lift+ tail4 ,lift is l>gely 9 proportion to ! l5g? ( ! ent]+ edge ( ! plane1 b x does n always foll[ t ?is ent]+ edge mu/ be at "r angles to ! direction ( flight4 ,! ,dunne ma*9e obta9s its lift ) an ent]+ edge t is entirely at an angle ( "s #de degrees1 & its %ape is an exact replica ( ! arr[ head ( prehi/oric man & ! pap] d>ts ( our s*ooldays1 a design1 by ! way1 t 0 pat5t$ 9 #ahfj4 ,at fir/ sight x w\ld seem t ! lift on a plane %ap$ ?us 7,fig4 #ah71 w\ld only be equal to ! lift giv5 by a plane ) an edge z long z ! di/ance betwe5 ,a & ,c1 ?us 7,fig4 #ai71 b ?is is n s4 ,al?\gh ! lift is n s great z x w\ld be if ! edge 0 /raight 9 "o l9e 7,fig4 #bj71 x is v mu* great] ?an x w\ld be on ,fig4 #ai4 ,! probability is t x is ab\t half-way betwe5 7#ai7 & 7#bj71 b probably ne>] to 7#bj7 ?an 7#ai74 ,!re are no exact data to g on1 b ! effici5cy ( ! ,dunne ma*9e w\ld seem to %[ ?is4 ,illu/ration3 ,,fig4 #ah4 ,illu/ration3 ,,fig4 #ai4 ,,& ,,fig4 #bj4 ,aga91 9 seek+ = planes t (f] ! lea/ resi/ance to ! air1 "o ( ! be/ t sugge/s itself is ! ,t-%ape 7,fig4 #ba71 & ?is may be improv$ by cutt+ (f useless corn]s 7,fig4 #bb74 ,a plane ( ?is %ape l5ds itself to great /r5g? ( con/ruction ow+ to its small ext5d+ p>ts4 ,x is compact1 x gives an ent]+ edge half z long aga9 z its span1 & gives a lift 9 proportion to t edge1 & x is 9 itself /able4 ,hav+ ?us evolv$ a suitable plane = ! front ( ! ma*9e1 ! be/ ?+ to d is to base ! back plane on ! same design1 & jo9 ! two planes toge!r to =m ! support+ surface ( ! ma*9e1 all[+ suffici5t space betwe5 !m to avoid any int]f]5ce or ov]lapp+4 ,! design !n /&s ?us 7,fig4 #bc71 :5 ! back plane is a slightly small] copy ( ! front "o4 ,! position ( ! c5tre ( gravity 9 ?is design w\ld be co9cid5t ) ! c5tre ( pressure longitud9ally & lat]ally1 & w\ld be situat$ ab\t at ,a4 ,a pap] model on ^! l9es ) a l[ c5tre ( gravity may be easily con/ruct$ & w prove useful 9 illu/rat+ ! diff]5t po9ts "h /at$4 ,! pap] %\ld be cut out suffici5tly wide to all[ ( a c5tral longitud9al fold 7,figs4 #bd & #be71 & a roll ( pap] %\ld be made = balla/ & pu%$ ?r\gh ! fold z %[n 9 ,fig4 #bf at ! po9t m>k$ ,a4 ,illu/ration3 ,,fig4 #ba4 ,,& ,,fig #bb4 ,illu/ration3 ,,fig4 #bc4 ,illu/ration3 ,,fig4 #bd4 ,,& ,,fig4 #be4 ,illu/ration3 ,,fig4 #bf4 ,! writ]1 :5 exhibit+ at ,olympia ?is ye>1 di/ribut$ #ejj ( ^! pap] models1 & ! almo/ uncanny way 9 :i* !y right$ !mselves :5 />t$ f all sorts ( impossible positions greatly int]e/$ ! visitors4 ,9 fact1 numb]s ( p]sons sp5t consid]able "t & +5uity 9 try+ to =ce ! little glid] to turn ov] or dive1 b q )\t success4 ,9 ord] to te/ ! turn+ capacity ( ?is design1 a rudd] %\ld be fix$ to ! tail1 & ! model laun*$ at a mod]ate spe$1 :5 x w be f\nd t x turns quickly & )\t any p5dulum motion1 & )\t any p]ceptible tilt4 ,& al?\gh ! writ]'s exp]im5ts ) ! pap] model & ) _m l>g] ones on ! same plan h run into ?\s&s1 none ( ! models h ev] be5 induc$ to come d[n 9 any o!r position b on _! feet4 ,! l>ge/ model1 :i* measur$ #f ft4 #f 94 9 l5g?1 0 laun*$ bo? upside d[n & ) its head po9t+ v]tically to e>? f a height ( #cj ft41 & 9 ea* case right$ be=e x rea*$ ! gr\nd & l&$ on its skids4 ,z a fur!r lift+ surface1 a v simple exp$i5t (f]s itself 9 ! %ape ( a duct built on ! box-kite pr9ciple4 ,! diamond-%ap$ box has be5 prov$ ov] & ov] aga9 to be a v effici5t lift+ device1 b x has n yet be5 tri$ on an a]oplane 7,fig4 #bg74 ,x is also a great /abiliz]1 s9ce ! air ent]+ into ! diamond-%ap$ op5+ is collect$ & compress$ into ! top angle !re1 & ! :ole box is ?us practically susp5d$ f its apex l9e 9 absolute /ability4 ,! lift+ effici5cy ( su* a box--or r ! top portion ( ! box1 = ! bottom "p is n ne$$ on our ma*9e--is consid]ably great] ?an ! value ( ! ent]+ edge1 & if run ! :ole l5g? ( ! ma*9e x =ms a triangul> gird] ( great /r5g?1 giv+ rigidity to ! :ole /ructure4 ,! lift+ effici5cy is d\bl$ by all[+ ! c5tre ?ird ( ! gird] to be op51 z ! dead air f ! front "p escapes1 & ! back "p =ms a new ent]+ edge4 ,illu/ration3 ,,fig4 #bg4 ,,& ,,fig4 #bh4 ,!re is also ano!r lift+ factor to be consid]$1 & ?is is ! c>4 ,if ! c> is =m$ ) a flat bottom1 ?is at once becomes an effici5t lift+ plane1 & if ! c> is susp5d$ ) an op5 space betwe5 x & ! "u surface ( ! plane1 ! loss caus$ by ! negative angle ( ! upp] portion ( ! c> front is comp5sat$ = by ! lift giv5 by ! deflect$ air to ! "u surface ( ! ma9 plane 7see ,fig4 #bh74 ,x w be recogniz$ t 9 ! design "h be+ gradually evolv$1 ! great lift+ surfaces ( ! ord9>y ma*9e h n be5 l>gely r$uc$1 !y h simply be5 brok5 up into sev]al small] surfaces1 ea* ( :i* reta9s its effici5cy4 ,some?+ ( ! same nature happ5$ 9 prehi/oric days1 :5 our fir/ navigators at la/ made up _! m9ds to ab&on ! flat-bottom$ raft ) its huge support+ surface1 = ! new-fangl$ & dang]\sly n>r[ boat4 ,:5 all ! diff]5t surfaces "h m5tion$ are tak5 into consid]ation1 x w be f\nd t ! lift+ surface 9 a monoplane ma*9e ( ?is design1 ) a span ( #bj feet1 is equal to ! lift+ surface ( an ord9>y bi-plane ) a span ( #dj feet4 ,& z ! head resi/ance is less ?an half t ( ! bi-plane ! spe$ %\ld be v mu* great]4 ,at ! same "t ! increas$ spe$ r5d]s ! planes m effici5t1 area = area1 ?an ! planes ( ! sl[] ma*9e4 ,,*apt] ,v4 ,,v>iable ,,spe$ ,,& ,,! ,,p>a*ute ,,pr9ciple4 ,hi!rto1 on ! score ( effici5cy & also ( /ability1 our inve/igations h l$ u to seek = spe$ z ! gr& panacea4 ,b !re are usually two sides to a "q1 & ?\gh1 :ile 9 ! air1 spe$ may be mo/ desirable1 x becomes a s\rce ( consid]able difficulty at bo? />t+ & l&+4 ,a ma*9e built to fly at #hj miles p] h\r w\ld h to get up some?+ l #fj miles p] h\r be=e x c\ld rise4 ,& ?is difficulty is no?+ l ! problem t pres5ts itself :5 we consid] h[ x is to l& 9 safety f a flight at su* a spe$4 ,x becomes evid5t t "s provision mu/ be made = />t+ & l&+ at "s m practicable rates2 we mu/ h a v>iable spe$ ma*9e4 ,to conv]t a high spe$ ma*9e into a l[ spe$ ma*9e means ei!r v>iable surface area1 v>iable camb]1 or v>iable angle ( incid5ce4 ,any ( ^! is possible1 b ! *oice mu/ be decid$ by simplicity ( action4 ,to spread extra w+s :5 ris+ or l&+ is a cumb]some sugge/ion full ( pitfalls & liable to accid5ts ?r\gh ! failure ( me*anical devices1 :i*1 exp]i5ce %[s1 always h a way ( fail+ at inopportune mom5ts4 ,to v>y ! camb] ( ! planes is easi]1 b hav+ decid$ on us+ flat planes x w\ld be loss ( /r5g? to make ^! flexible1 & an increase ( me*anical complications to h to flex !m4 ,x w\ld be easy to alt] ! angle ( incid5ce by hav+ ! lead+ edge capable ( a rot>y movem5t1 & ma*9es h be5 con/ruct$ employ+ ?is pr9ciple4 ,b ! easie/ plan ( all1 s9ce x does away ) all mov+ p>ts :atev]1 w\ld be to alt] n ! planes !mselves1 b ! :ole ma*9e4 ,?us suppose ! angle ( incid5ce1 9 ord] to get an effici5t lift1 to be #a 9 #f1 ! lift+ plane1 all 9 ! same l9e1 w\ld be set on its *assis s t x pres5t$ an angle ( #a 9 #e4 ,! ma*9e w\ld !n lift at a mu* sl[] spe$4 ,naturally1 ! tail be+ ! fur!/ f ! c5tre ( gravity w\ld lift fir/1 & z soon z ! spe$ 0 suffici5t ! pilot w\ld alt] ! elevator1 s5d d[n ! tail on to ! gr\nd1 !reby rais+ ! lead+ edge ( ! front plane1 & ! ma*9e w\ld rise4 ,z ! spe$ increas$ ! tail w\ld cont9ue to rise1 till1 at ! maximum spe$1 ! plane w\ld be at ! m9imum angle ) ! horizontal1 i4e4 at its l[e/ angle ( incid5ce4 ,?is solves ! problem ( />t+ & to "s ext5t ( l&+1 b we h n yet come to ! end ( our res\rces4 ,mo/ l&+s are effect$ by %utt+ (f ! eng9e & plan+ d[n4 ,all fly+ ma*9es w glide if put at ! prop] angle1 & x is ! bus9ess ( ! pilot to att5d to ?is :5 he /ops ! eng9e4 ,b to glide ) ! same w+ area z is us$ 9 fly+1 means to glide at ! same rate4 ,9 ord] to desc5d sl[ly x is necess>y to h m area4 ,is x possible to increase ! area us$ = desc5t )\t int]f]+ ) ! area us$ = flight8 ,9 ! design we are engag$ 9 consid]+1 x is possible1 & )\t any me*anical devices4 ,!re is a l>ge space betwe5 ! front plane & ! back plane :i* is at pres5t unus$4 ,x is ( v little value 9 flight1 be+ 9 apt]oid aspect & hav+ practically no ent]+ edge4 ,b if ?is space is cov]$ 9 x gives no resi/ance 9 flight1 & 9 desc5t x becomes a v effici5t p>a*ute4 ,fur!r ?an ?is1 if op5+s be cut 9 ?is plane imm$iately "u ! c5tre ( ! two box-kite ducts1 ! air "u ! longitud9al plane1 hav+ (f]$ its resi/ance to ! v]tical passage ( t plane1 w escape into ! duct & aga9 (f] consid]able resi/ance to ! desc5t ( ?is clos$-9 surface be=e x escapes f9ally out ( ! end ( ! duct4 ,a model made on ^! l9es w n ne$ putt+ at any angle4 ,x w assume its prop] angle :5 left to itself by reason ( its design & ! way ! weight is balanc$ betwe5 ! support+ planes1 & x w desc5d by p>tly glid+ & p>tly p>a*ut+ at a /eep angle b q sl[ly4 ,:ile1 if ! pilot s *oose1 he c1 by rais+ ! tail1 increase ! spe$ to a glide1 :i* he c turn into a p>a*ute action at any mom5t4 ,,*apt] ,,vi4 ,,! ,,design ,,:i* ,,fulfils ,,! ,,conditions4 ,9 con/ruct+ any sort ( ma*9e x is usual to fir/ obta9 ! mo/ important device & !n to build up ! accompany+ p>ts to t4 ,we h n[ succe$$ 9 evolv+ ! ?+ we set out to look =1 i4e41 a plane :i* w fly & lift ) ! m9imum ( head resi/ance1 & :i* is absolutely /able lat]ally & longitud9ally by reason ( its con/ruction & )\t any int]f]5ce f ! pilot or ! employm5t ( balanc+ devices ( any description4 ,we h n[ to fit ! propell+ app>atus1 c>1 & *assis on to ?is4 ,=tunately1 ! design is "o t l5ds itself easily to manipulation1 :i* is n always ! case ) models4 ,! %ort span ( ! planes1 = in/ance1 ) ! dih$ral angle1 at once sugge/s gird] con/ruction 7see ,figs4 #bi1 #cj71 :i* is1 p]haps1 ! /ronge/ ( all devices1 be+ an ,m /rut gird]1 famili> to u 9 numb]less bridges4 ,illu/ration3 ,,fig4 #bi4 ,,& ,,fig4 #cj4 ,! photo :i* =ms ! frontispiece ( ?is book1 & :i*1 by ! way1 makes ! c> look mu* too l>ge ow+ to its position ne>e/ ! cam]a1 repres5ts a #f-;foot model :i* 0 exhibit$ at ! ,olympia ,%[1 9 ord] to %[ ! con/ruction ( a full-siz$ ma*9e made to ! design ( ! pap] model4 ,?is has s9ce be5 consid]ably simplifi$1 ?\gh ! broad l9es h be5 reta9$1 by do+ away ) ! /ruts & supports at ! re>4 ,! :ole ( ! back plane is n[ support$ by two curv$ memb]s1 :i* />t f ! gird] ( ! lead+ edge & curve d[n to ! ,t-section longitud9als :i* =m ! rigid "p ( ! *assis4 ,^! longitud9als & ! skids end at ! lead+ edge ( ! back plane & ! lam9at$ skids & :eels are plac$ !re4 ,! ma*9e is built )\t a wire & )\t a ca/+4 ,x 0 made entirely ( wood1 b is s design$ t x c be made entirely out ( /eel tube by us+ ! ord9>y screw connexions4 ,if built ( timb]1 ! jo9ts are made ) /rips ( /eel bolt$ & screw$ on to ! wood4 ,! gird]s =m+ ! lead+ edge ( ea* plane h sockets =m$ 9 ! upright /ruts ( ! ,m into :i* ! ribs fit 7see ,fig4 #cj71 & ^! are solid pieces on edge tap]+ to ! trail+ edge1 :]e !y are clipp$ to a slight sp> :i* holds !m toge!r4 ,?is con/ruction1 :ile v /rong1 is yet suffici5tly flexible to b5d consid]ably be=e x rea*es break+ po9t4 ,longitud9al rigidity is secur$ by means ( ! triangul> duct :i* =ms a complete gird] f end to end4 ,a suffici5t numb] ( uprights fill ! space betwe5 ! plane & ! two ,t-section longitud9als :i* =m ! rigid bottom ( ! ma*9e4 ,on ^! latt] ! floor is plac$ & ! c> is built up1 enclos+ all ! ob/ructions & putt+ ! pilot 9 a place ( safety1 enclos$ on all sides 9 ! middle ( ! /ronge/ "p ( ! ma*9e1 ) ! /ronge/ portion ( t "p betwe5 him & ! gr\nd4 ,! c5tre ( gravity is situat$ beh9d ! pilot 9 ! back ( ! c>1 ne> ! floor1 & "h is space = ! oil & petrol tanks4 ,! eng9e is 9 front ( ! pilot1 :o is ?us able to control x & wat* x1 & at ! same "t is free f ! dang] ( hav+ x fall ^u him 9 case ( an accid5t4 ,z ! ma*9e turns horizontally & v]tically on its c5tre ( gravity1 ! front "p ( ! c> =ms a sort ( baffle or bl9k] = ! rudd] & elevator to act aga9/4 ,bo? ^! are at ! tail ( ! ma*9e1 :]e !y h ! mo/ lev]age1 & ^! two are controll$ by ! "o lev]1 :i* is pu%$ =w>d or pull$ backw>d to raise or l[] ! elevator1 & turn$ bicycle fa%ion to move ! rudd]4 ,z ! ma*9e balances itself1 !re is no ne$ = any balanc+ device ei!r automatic or controll$4 ,illu/ration3 ,,fig4 #ca4 ,! propell]s may be two or m1 & ^? 9 front f9d a v firm fix+ 9 ! int]section ( two /rong /ruts1 :i* jo9 ! w+tips to ! bottom ( ! c>1 & ! supports :i* run f ! c5tre ( ^! to ! /rong jo9t =m$ by ! int]section ( ! longitud9al & lat]al gird]4 ,at ! back !re may be two propell]s fix$ z 9 ! front1 or "o l>ge "o at ! re> ( ! c>4 ,!y are all work$ f ! "o eng9e & ! ?ru/ is slightly above ! c5tre ( gravity4 ,ea* propell] is plac$ j "u ! lead+ edge ( a plane1 ,fig4 #ca1 ! idea be+ t a c]ta9 am\nt ( air is always ?r[n out by c5trifugal =ce all r\nd a revolv+ propell]1 & ?is air1 :i*1 ord9>ily1 is lo/1 mu/1 :5 ?r[n upw>ds1 ex]t a lift on ! "u surface ( ! plane4 ,also1 :5 ?r[n t[>ds ! c>1 x mu/1 by imp++ on ! slant+ surface ( ! c>1 t5d to impel x =w>d1 ,fig4 #cb4 ,:]e f\r propell]s are us$1 ! back pair %\ld be ( great] pit* ?an ! front pair1 z !y mu/ to a c]ta9 ext5t1 "w 9 ! /ream f ! front pair4 ,!re are sev]al ways ( c\pl+ ! propell]s to ! eng9e1 b 9 ! model !y are %[n c\pl$ up by belts1 :i* seems to be ! mo/ effici5t & lighte/ device4 ,illu/ration3 ,,fig4 #cb4 ,9 ord] to cool ! eng9e & keep ! air 9 ! c> cle>1 a v5tilat+ pipe is l$ f ! front ( ! c> to ! eng9e1 & ! air1 ru%+ ?r\gh ?is at ! spe$ ( ! ma*9e1 plays ov] ! eng9e & is conduct$ out ?r\gh a l>ge op5+ & dis*>g$ at ! back4 ,! :ole ( ?is "p ( ! ma*9e is rigid & brac$ toge!r by means ( /ruts1 ?\gh :e!r made ( /eel tube or timb]1 !re mu/ always1 f ! nature ( ! con/ruction1 be a c]ta9 am\nt ( ela/icity :i* makes = /r5g?1 a great advantage ov] a con/ruction brac$ rigidly by non-ela/ic wires1 :i* snap in/ead ( giv+ to a sudd5 /ra94 ,"u ! two rigid ,t-section longitud9als !re are a numb] ( ela/ic lam9at$ wood spr+s set at an angle1 & ! l[] ends ( ^! are pivot$ on to a long ela/ic skid4 ,?is skid is made 9 lam9ations1 ) alt]nate jo9ts1 & />ts f ! po9t :]e ! two planes int]sect 9 ! front ( ! ma*9e1 :i* is "o ( ! /ronge/ jo9ts 9 ! :ole con/ruction4 ,f ?is po9t x b5ds out 9 a semicircle to protect ! propell] & ! front ( ! ma*9e & c>1 ?is portion ( x be+ v ela/ic by reason ( ! lam9ations hav+ free play "o ^u ! o!r4 ,at ! bottom ( ! semicircle ! skid is jo9$ to ! slant+ skids or spr+s dep5d+ f ! bottom ( ! ma*9e1 & "h ! lam9ations are bolt$ toge!r mak+ ! skid /iff]4 ,! skid runs ! :ole l5g? ( ! ma*9e l ! runn] ( a sl$ge4 ,on ?is skid ! :eels are sprung ) a /eel spr+ lev] arrangem5t1 ,fig4 #cc4 ,! %ock ( l&+ is1 !re=e1 tak5 fir/ on ! :eels1 & %\ld x be suffici5tly heavy to cause ! skids to t\* ! gr\nd !re is /ill ! s]ies ( lam9at$ wood spr+s to absorb any vibrations & prev5t any possible %ock to ! c>4 ,! c> is s secure f vibration by reason ( ^! precautions t ! :ole l[] half ( ! front ( x may be made ( protect$ glass1 to enable ! pilot to get a cle> view ( 8 surr\nd+s4 ,illu/ration3 ,,fig4 #cc4 ,! dim5sions ( ! full-siz$ ma*9e are e/imat$ to be z foll[s3-- ,span #bj feet ,l5g? #dc feet ,p>a*ut+ area #ejj squ>e feet ,effici5t lift+ area #cfj squ>e feet ,weight 7all up7 #hjj lb4 ,x w be und]/ood t ?\gh only #cfj squ>e feet is c\nt$ z effici5t = lift+1 ! :ole #ejj squ>e feet is effici5t z p>a*ut+ surface 9 desc5d+4 ,! weight ( ! ma*9e comp>es v fav\rably ) exi/+ ma*9es1 & ! load #b-a_/d lbs4 p] squ>e foot1 gives pl5ty ( m>g9 = pass5g] c>ry+4 ,! *ief advantages claim$ = ?is ma*9e are3-- 7#a7 ,spe$4 7#b7 ,/ability4 7#c7 ,/r5g? ( con/ruction4 7#d7 ,%ock absorb+ capacity4 ,x is a practical impossibility = ! ma*9e to turn ov] or be bl[n ov]1 & x w recov] its balance if />t$ at any angle4 ,if all[$ to dive v]tically1 ei!r tail fir/ or head fir/1 x w recov] its position 9 six times its own l5g?1 purely by its own balance1 )\t any ef=t ( ! pilot4 ,,london3 ,,pr9t$ ,,by ,,william ,,cl[es ,,& ,,sons1 ,,limit$1 ,,great ,,w9dmill ,,/reet1 ,w41 ,,& ,,duke ,,/reet1 ,,/am=d ,,/reet1 ,s4,e4