,,! ,,a]oplane ,,speaks ,by ,h4 ,b>b] 7,capta91 ,royal ,fly+ ,corps7 ,,d$icat$ ,,to ,,! ,,subalt]n ,,fly+ ,,(fic] ,,motive ,! reasons impell+ me to write ?is book1 ! maid5 ef=t ( my p51 are1 fir/ly1 a /rong desire to help ! ord9>y man to und]/& ! ,a]oplane & ! joys & tr\bles ( its ,pilot2 &1 secondly1 to produce some?+ ( ,,practical assi/ance to ! ,pilot & 8 invaluable assi/ant ! ,rigg]4 ,hav+ _h "s eight ye>s' exp]i5ce 9 design+1 build+1 & fly+ a]oplanes1 ,i h hopes t ! practical k ,i h ga9$ may (fset ! disadvantage ( a h& m us$ to manag+ ! 8joy-/ick0 ?an ! dreadful halt+s1 ! _m side-slips1 ! irregul> spe$1 &1 9 %ort1 ! altoge!r disconc]t+ ways ( a p54 ,! matt] conta9$ 9 ! ,prologue appe>$ 9 ! ,field ( ,may #f?1 #ac?1 #bj?1 & #bg?1 #aiaf1 & is n[ repr9t$ by ! k9d p]mission ( ! editor1 ,sir ,!odore ,cook4 ,i h mu* pleasure 9 also ackn[l$g+ ! k9dness ( ,mr4 ,c4 ,g4 ,grey1 editor ( ! ,a]oplane1 to :om ,i am indebt$ = ! valuable illu/rations reproduc$ at ! end ( ?is book4 ,,cont5ts ,,prologue ,,"p ,i4 ,,! ,,elem5t>y ,,pr9ciples ,,air ,,_! ,,grievances ,,ii4 ,,! ,,pr9ciples1 ,,hav+ ,,settl$ ,,_! ,,diff]5ces1 ,,f9i% ,,! ,,job ,,iii4 ,,! ,,great ,,te/ ,,iv4 ,,cross ,,c\ntry ,,*apt] ,i4 ,,flight ,,ii4 ,,/ability ,,& ,,control ,,iii4 ,,rigg+ ,,iv4 ,,propell]s ,v4 ,,ma9t5ance ,,types ,,( ,,a]oplanes ,,gloss>y ,,! ,,a]oplane ,,speaks ,,prologue ,,"p ,i4 ,,! ,,elem5t>y ,,pr9ciples ,,air ,,_! ,,grievances ,! ,lecture ,hall at ! ,royal ,fly+ ,corps ,s*ool = ,(fic]s 0 des]t$4 ,! pupils _h disp]s$1 & ! ,(fic] ,in/ructor1 m fagg$ ?an any pupil1 0 out on ! a]odrome wat*+ ! te/ ( a new ma*9e4 ,des]t$1 did ,i say8 ,b n s4 ,! lecture t day _h be5 ^u ! ,elem5t>y ,pr9ciples ( ,flight1 & !y l+]$ yet4 ,^u ! ,blackbo>d 0 ! illu/ration y see 9 ! frontispiece4 8,i am ! side view ( a ,surface10 x said1 mimick+ ! tones ( ! lectur]4 8,flight is secur$ by driv+ me ?r\gh ! air at an angle incl9$ to ! direction ( motion40 8,q "r10 said ! ,angle4 8,t's me1 & ,i'm ! fam\s ,angle ( ,incid5ce40 8,&10 cont9u$ ! ,surface1 8my action is to deflect ! air d[nw>ds1 & also1 by flee+ f ! air beh9d1 to create a semi-vacuum or r>efi$ area ov] mo/ ( ! top ( my surface40 8,?is is :]e ,i come 910 a ?ick1 gruff voice 0 he>d1 & w5t on3 8,i'm ! ,reaction4 ,y c't h action )\t me4 ,i'm a v consid]able =ce1 & my direction is at "r-angles to y10 & he look$ heavily at ! ,surface4 8,l ?is10 said he1 pick+ up ! *alk ) 8 ,lift1 & drift+ to ! ,blackbo>d4 8,i act 9 ! direction ( ! arr[ ,r1 t is1 m or less1 = ! direction v>ies some:at ) ! ,angle ( ,incid5ce & ! curvature ( ! ,surface2 &1 /range b true1 ,i'm /rong] on ! top ( ! ,surface ?an at ! bottom ( x4 ,! ,w9d ,tunnel has prov$ t by exhau/ive rese>*--& don't =get h[ quickly ,i c gr[6 ,z ! spe$ ?r\gh ! air increases my /r5g? increases m rapidly ?an y might ?9k--approximately1 z ! ,squ>e ( ! ,spe$2 s y see t if ! ,spe$ ( ! ,surface ?r\gh ! air is1 = in/ance1 d\bl$1 !n ,i am a good deal m ?an d\bl$4 ,t's because ,i am ! result ( n only ! mass ( air displac$1 b also ! result ( ! ,spe$ ) :i* ! ,surface engages ! ,air4 ,i am a product ( ^? two factors1 & at ! spe$s at :i* ,a]oplanes fly to-day1 & at ! altitudes & consequ5t d5sity ( air !y at pres5t exp]i5ce1 ,i increase at ab\t ! ,squ>e ( ! ,spe$4 8,oh1 ,i'm a mo/ complex & int]e/+ p]sonality1 ,i assure y--9 fact1 a dual p]sonality1 a sort ( a]onautical ,dr4 ,jekyll & ,mr4 ,hyde4 ,!re's ,lift1 my v]tical "p or ,,compon5t1 z ^? :o pref] long words w\ld say2 he always acts v]tically upw>ds1 & hates ,gravity l poison4 ,he's ! useful & admirable "p ( me4 ,!n !re's ,drift1 my horizontal compon5t1 sometimes1 ?\gh r errone\sly1 call$ ,head ,resi/ance2 he's a villa9 ( ! deepe/ dye1 & mu/ be ov]come be=e flight c be secur$40 8,& ,i10 said ! ,propell]1 8,i screw ?r\gh ! air & produce ! ,?ru/4 ,i ?ru/ ! ,a]oplane ?r\gh ! air & ov]come ! ,drift2 & ! ,lift increases ) ! ,spe$ & :5 x equals ! ,gravity ( ,weight1 !n--!re y are--,flight6 ,& no?+ my/]i\s ab\t x at all40 8,i hope y'll excuse me int]rupt+10 said a v beautiful "y lady1 8my "n is ,effici5cy1 &1 :ile no d\bt1 all y h said is q true1 & t1 z my "y man ! ,design] says1 ,y c make a tea-tray fly if y slap on ,p[] en\gh1' ,i c assure y t ,i'm n to be won q s easily40 8,well10 eag]ly repli$ ! ,lift & ! ,?ru/1 8let's be fri5ds4 ,d tell u :at we c d to help y to ov]come ,gravity & ,drift ) ! lea/ possible ,p[]4 ,t obvi\sly seems ! game to play1 = m ,p[] means heavi] eng9es1 & t 9 a way plays into ! h&s ( our enemy1 ,gravity1 besides necessitat+ a l>g] ,surface or ,angle to lift ! ,weight1 & t increases ! ,drift40 8,v well10 f ,effici5cy1 8,i'll d my be/1 ?\gh ,i'm s %y1 & ,i've j _h su* a bad "t at ! ,factory1 & ,i'm t]ribly afraid y'll f9d x awfully dry40 8,buck up1 old de>60 ,?is f sev]al new-com]s1 :o _h j appe>$4 8,we'll help y10 & "o ( !m1 s lean & long t he took up ! :ole height ( ! lecture room1 introduc$ himself4 8,i'm ! ,high ,aspect ,ratio10 he said1 8& :at we h got to d to help ?is "y lady is to improve ! proportion ( ,lift to ,drift4 ,! m ,lift we c get = a c]ta9 area ( ,surface1 ! great] ! ,weight ! latt] c c>ry2 & ! less ! ,drift1 !n ! less ,?ru/ & ,p[] requir$ to ov]come x4 ,n[ x is a fact t1 if ! ,surface is %ap$ to h ! greate/ possible span1 i4e41 di/ance f w+-tip to w+-tip1 x !n engages m air & produces bo? a maximum ,reaction & a bett] proportion ( ,lift to ,drift4 8,t be+ s1 we c !n well af=d to lose a little ,reaction by r$uc+ ! ,angle ( ,incid5ce to a degree giv+ a /ill bett] proportion ( ,lift to ,drift ?an w\ld o!rwise be ! case2 = y mu/ und]/& t ! ,lift-,drift ,ratio dep5ds v mu* ^u ! size ( ! ,angle ( ,incid5ce1 :i* %\ld be z small z possible )9 c]ta9 limits4 ,s :at ,i say is1 make ! surface ( ,inf9ite ,span ) no wid? or *ord1 z !y call x4 ,t's all ,i require1 ,i assure y1 to make me q p]fect & ( inf9ite s]vice to ,miss ,effici5cy40 8,t's n practical politics10 said ! ,surface4 8,! way y talk "o w\ld ?9k y 7 draw+ ,l#djj a ye> at ,we/m9/]1 & work+ up a reputation z an ,a]onautical ,exp]t4 ,i mu/ h "s dep? & *ord to take my ,sp>s & ,ribs1 & aga91 ,i mu/ h a c]ta9 *ord to make x possible = my ,camb] 7t's curvature7 to be j "r = ! ,angle ( ,incid5ce4 ,if t's n "r ! air won't get a nice uni=m compression & d[nw>d accel]ation f my und]side1 & ! r>efi$ suction' area ov] ! top ( me w n be z ev5 & clean 9 effect z x might be4 ,t w\ld spoil ! ,lift-,drift ,ratio m ?an y c help x4 ,j ?ru/ t *alk along1 w y8 & ! ,blackbo>d w %[ y :at ,i mean40 8,well10 said ! ,aspect ,ratio1 8h x y\r own way1 ?\gh ,i'm sorry to see a pretty "y lady l ,effici5cy compromis$ s e>ly 9 ! game40 8,look "h10 exclaim$ a numb] ( ,/ruts1 8we h got a brilliant idea = improv+ ! ,aspect ,ratio10 & ) t !y hopp$ up on to ! ,sp>s4 8,n[10 excit$ly1 8place ano!r ,surface on top ( u4 ,n[ d y see8 ,!re is d\ble ! ,surface1 & t be+ s1 ! proportion ( ,weight to ,surface area is halv$4 ,t's less burd5 ( "w = ! ,surface1 & s ! ,sp>s ne$ n be s /rong & s deep1 :i* results 9 n s ?ick a ,surface4 ,t means ! ,*ord c be proportionately decreas$ )\t adv]sely affect+ ! ,camb]4 ,) ! ,*ord decreas$1 ! ,span becomes relatively great]1 & s produces a spl5did ,aspect ,ratio1 & an excell5t proportion ( ,lift to ,drift40 8,i don't d5y t !y h r got me !re10 said ! ,drift1 8b all ! same1 don't =get my increase due to ! drift ( ! ,/ruts & _! brac+ wires40 8,yes1 ,i d>e say10 repli$ ! ,surface1 8b rememb] t my ,sp>s are less deep ?an be=e1 & consequ5tly ,i am n s ?ick n[1 & %all = t reason also be able to g ?r\gh ! air ) a less proportion ( ,drift to ,lift40 8,rememb] me also1 please10 croak$ ! ,angle ( ,incid5ce4 8,s9ce ! ,surface has n[ less weight to c>ry = its area1 ,i may be set at a /ill less] & f9] ,angle4 ,t means less ,drift aga94 ,we are c]ta9ly gett+ on spl5didly6 ,%[ u h[ x looks n[1 ,blackbo>d40 ,& ! ,blackbo>d oblig+ly %[$ !m z foll[s3 8,well1 :at d y ?9k ( t80 !y all cri$ to ! ,drift4 8,y ?9k y are v clev]10 sne]$ ! ,drift4 8,b y are n help+ ,effici5cy z mu* z y ?9k4 ,! suction effect on ! top ( ! l[] ,surface w give a d[nw>d motion to ! air above x & ! result w be t ! bottom ( ! top ,surface w n secure z good a ,reaction f ! air z w\ld o!rwise be ! case1 & t means loss ( ,lift2 & y c't help matt]s by increas+ ! gap betwe5 ! surfaces because t means long] ,/ruts & ,wires1 & t 9 itself w\ld help me1 n to speak ( increas+ ! ,weight4 ,y see x's n q s easy z y ?\ght40 ,at ?is mom5t a hicc\gh 0 he>d1 & a r fa/ & raki%-look+ *ap1 nam$ ,/agg]1 spoke up4 8,h[ d'ye d1 miss10 he said politely to ,effici5cy1 ) a side glance out ( 8 wick$ old eye4 8,i'm a bit ( a knut1 & )\t ! slighte/ tr\ble ,i c easily m9imize ! disadvantage t old reprobate ,drift has be5 fright5+ y )4 ,i j /agg] ! top ,surface a bit =w>d1 & no long] is t suction effect dead "u x4 ,at ! same "t ,i'm sure ! top ,surface w k9dly ext5d its ,span = su* di/ance z its ,sp>s w support x )\t ! aid ( ,/ruts4 ,su* ext5sion w be q useful1 z !re w be no ,surface at all und]nea? x to int]f]e ) ! ,reaction above40 ,& ! ,/agg] lean$ =w>d & pick$ up ! ,*alk1 & ?is is ! picture he drew3 ,said ! ,blackbo>d1 8,t's n half bad6 ,x really beg9s to look some?+ l ! real ?+1 eh80 8,! real ?+1 is x80 grumbl$ ,drift4 8,j consid] t contraption 9 ! light ( any "o ,pr9ciple1 & ,i w>rant y w n f9d "o ( !m appli$ to p]fection4 ,! :ole ?+ is no?+ b a ,compromise40 ,& he gl>$ fix$ly at poor ,effici5cy4 8,oh1 de>6 ,oh1 de>60 %e cri$4 8,i'm always gett+ into tr\ble4 ,:at ,,w ! ,design] say80 8,nev] m9d1 my de>10 said ! ,lift-,drift ,ratio1 consol+ly4 8,y are improv+ rapidly1 & q useful en\gh n[ to ?9k ( do+ a job ( "w40 8,well1 t's good news10 & ,effici5cy wip$ h] eyes ) h] ,fabric & became almo/ *e]ful4 8,suppose we ?9k ab\t f9i%+ x n[8 ,!re w h to be an ,eng9e & ,propell]1 won't !re8 ,& a body to fix !m 91 & tanks = oil & petrol1 & a tail1 &10 ar*ly1 8"o ( ^? da%+ "y ,pilots1 :at80 8,well1 we are gett+ )9 sight ( ^? int]e/+ ,factors10 said ! ,lift-,drift ,ratio1 8b fir/ ( all we _h bett] decide ^u ! ,area ( ! ,surfaces1 _! ,angle ( ,incid5ce & ,camb]4 ,if we are to asc5d z quickly z possible ! ,a]oplane mu/ be ,,sl[ 9 ord] to secure ! be/ possible ,lift-,drift ,ratio1 = ! drift ( ! /ruts wires1 body1 etc41 increases approximately z ! squ>e ( ! spe$1 b x c>ries ) x no lift z x does 9 ! case ( ! ,surface4 ,! less spe$ !n1 ! less su* drift1 & ! bett] ! ,a]oplane's proportion ( lift to drift2 &1 be+ sl[1 we %all require a ,,l>ge ,,surface 9 ord] to secure a l>ge lift relative to ! weight to be c>ri$4 ,we %all also require a ,,l>ge ,,angle ,,( ,,incid5ce relative to ! horizontal1 9 ord] to secure a prop] incl9ation ( ! ,surface to ! direction ( motion1 = y mu/ rememb] t1 :ile we %all fly ^u an ev5 keel & ) ! propell] ?ru/ horizontal 7:i* is its mo/ effici5t attitude71 our flight pa?1 :i* is our direction ( motion1 w be slop+ upw>ds1 & x w !re=e be necess>y to fix ! ,surface to ! ,a]oplane at a v consid]able angle relative to ! horizontal ,propell] ,?ru/ 9 ord] to secure a prop] angle to ! upw>ds direction ( motion4 ,ap>t f t1 we %all require a l>g] ,angle ( ,incid5ce ?an 9 ! case ( a ma*9e design$ purely = spe$1 & t means a correspond+ly ,,l>ge ,,camb]4 8,on ! o!r h&1 if we are ?9k+ m]ely ( ,spe$1 !n a ,,small ,,surface1 j en\gh to lift ! weight (f ! gr\nd1 w be be/1 also a ,,small ,,angle to cut ! ,drift d[n & t1 ( c\rse1 means a relatively ,,small ,,camb]4 8,s y see ! ess5tials = ,,climb or quick asc5t & = ,,spe$ are diametrically oppos$4 ,n[ :i* is x to be80 8,no?+ b p]fection = me10 said ,effici5cy4 8,:at ,i want is ,maximum ,climb & ,maximum ,spe$ = ! ,p[] ! ,eng9e produces40 ,& ea* ,pr9ciple fully agre$ ) h] beautiful s5tim5ts1 b "w toge!r !y w\ld n4 ,! ,aspect ,ratio want$ inf9ite ,span1 & hang ! ,*ord4 ,! ,angle ( ,incid5ce w\ld h two ,angles & two ,camb]s 9 "o1 :i* 0 manife/ly absurd2 ! ,surface insi/$ ^u no ?ickness :atev]1 & w\ld n he> ( su* ?+s z ,sp>s & ,ribs2 & ! ,?ru/ object$ to any?+ at all likely to produce ,drift1 & v ne>ly wip$ ! :ole ?+ (f ! ,blackbo>d4 ,!re 01 inde$1 ! mak+s ( a v pretty qu>rel :5 ! ,lett] arriv$4 ,x 0 ab\t a mile long1 & began to talk at once4 8,i'm f ! ,inv5tor10 he said1 & hope rose 9 ! he>t ( ea* heat$ ,pr9ciple4 8,x's really absurdly simple4 ,all ! ,pilot has to d is to t\* a button1 & at 8 w1 ,,v>y ! area ( ! ,surface1 ! ,angle ( ,incid5ce1 & ! ,camb]6 ,& !re y are--,maximum ,climb or ,maximum ,spe$ z requir$6 ,h[ does t suit y80 8,t suits u v well10 said ! ,surface1 8b1 excuse me ask+1 h[ is x done )\t app>atus increas+ ! ,drift & ! ,weight out ( all reason8 ,y won't m9d %[+ u y\r ,calculations1 ,work+ ,draw+s1 ,/ress ,diagrams1 etc41 w y80 ,said ! ,lett] ) dignity1 8,i come f an ,inv5tor s brilliantly clev] z to be f> above ! unimportant matt]s y m5tion4 ,he is no common work+ man1 sir6 ,he leaves su* ?+s to ,me*anics4 ,! po9t is1 y press a button &----0 8,look "h10 said a ,/rut1 r po9t$ly1 8:]e d y ?9k y are go+1 anyway80 8,well10 f ! ,lett]1 8z a matt] ( fact1 ,i'm n address$ yet1 b1 ( c\rse1 !re's no d\bt ,i %all rea* ! v highe/ qu>t]s & absolutely revolutionize ,flight :5 ,i get !re40 ,said ! ,*alk1 8,i'll address y1 if t's all y want2 n[ drift along quickly60 ,& (f w5t ! ,lett] to ,! ,te*nical ,editor1 8,daily ,maul]10 ,london4 ,& a ,league 0 =m$1 & !re 7 ,directors ) ,fees1 & sev]al out-(-s]vice ,t9 ,hats1 & ! ,man-:o-takes-!-cr$it1 & a f9e fat ,gu9ea-pig1 & all ! re/ ( !m4 ,& ! ,inv5tor paid 8 ,tailor & _h a ,hair-,cut1 & is n[ a recogniz$ ,press ,exp]t--b he is /ill wait+ = ^? ,me*anics6 8,i'm afraid10 said ! ,slide-rule1 :o _h be5 busy mak+ ^? lightn+-l automatic calculations = :i* he is s fam\s1 8x's q impossible to fully satisfy all ( y1 & x is p]fectly pla9 to me t we %all h to effect a ,compromise & sacrifice "s ( ! ,lift = ,spe$40 ,?ud6 ,:at 0 t8 ,effici5cy _h fa9t$ dead away6 ,! la/ bl[ _h be5 too mu* = h]4 ,& ! ,pr9ciples ga!r$ m\rnfully r\nd1 b ) ! aid ( ! ,propell] ,slip#a & a fri5dly lift f ! ,surface %e 0 at l5g? reviv$ & rega9$ a m normal aspect4 ,said ! ,/agg] ) a raffi% air1 8,my de> "y lady1 ,i assure y t f ! exp]i5ces ( a v>i$ c>e]1 ,i h le>n$ t p]fection is impossible1 & ,i am sure ! ,design] w be q satisfi$ if y become ! ,mo/ ,effici5t ,compromise40 8,well1 t s\nds s common s5se10 sigh$ ,effici5cy1 8,i suppose x mu/ be true1 & if ! ,design] is satisfi$1 t's all ,i really c>e ab\t4 ,n[ d let's get on ) ! job40 ,s ! ,*alk drew a nice long slim body to hold ! ,eng9e & ! tanks1 etc41 ) room = ! ,pilot's & ,pass5g]'s seats1 & plac$ x exactly 9 ! middle ( ! ,biplane4 ,& he 0 c>eful to make its position su* t ! ,c5tre ( ,gravity 0 a little 9 advance ( ! ,c5tre ( ,lift1 s t :5 ! ,eng9e 0 n runn+ & !re 0 consequ5tly no ,?ru/1 ! ,a]oplane %\ld be 8nose-heavy0 j to ! "r degree1 & s take up a natural glide to ,e>?--& ?is 0 to help ! ,pilot & relieve him ( "w & worry1 %\ld he f9d himself 9 a fog or a cl\d4 ,& s t ?is t5d5cy to glide d[nw>ds %\ld n be 9 evid5ce :5 ! ,eng9e 0 runn+ & desc5t n desir$1 ! ,?ru/ 0 plac$ a little bel[ ! ,c5tre ( ,drift or ,resi/ance4 ,9 ?is way x w\ld 9 a measure pull ! nose ( ! ,a]oplane up & c\nt]balance ! 8nose-heavy0 t5d5cy4 ,& ! ,eng9e 0 s m\nt$ t :5 ! ,propell]-,?ru/ 0 horizontal1 :i* is its mo/ effici5t position1 ! ,angle ( ,incid5ce & ! ,area ( ! surfaces 7 j suffici5t to give a ,lift a little 9 excess ( ! ,weight4 ,& ! ,camb] 0 su* t1 z f> z x 0 conc]n$1 ! ,lift-,drift ,ratio %\ld be ! be/ possible = t ,angle ( ,incid5ce4 ,& a beautifully simple "u-c>riage 0 add$1 ! out/&+ features ( :i* 7 simplicity1 /r5g?1 light-weight1 & m9imum drift4 ,&1 la/ ( all1 !re 0 ! ,elevator1 ( :i* y w he> m by-&-by4 ,& ?is is :at x look$ l !n3 ,& ,effici5cy1 smil+1 ?\ght t x 0 n su* a bad compromise aft] all & t ! ,design] might well be satisfi$4 8,n[10 said %e1 8!re's j "o or two po9ts ,i'm a bit hazy ab\t4 ,x appe>s t :5 ! ,propell] %aft is horizontal & s work+ 9 its mo/ effici5t attitude1 ,i %all h a ,lift f ! ,surfaces slightly 9 excess ( ! ,weight4 ,t means ,i %all asc5d slightly1 at ! same "t mak+ ne>ly maximum spe$ = ! p[] & ?ru/4 ,c't ,i d bett] ?an t80 8,yes1 inde$10 spoke up ! ,propell]1 8?\gh x means t ,i mu/ assume a mo/ undignifi$ attitude1 = helicopt]s#b ,i nev] approv$ (4 ,9 ord] to asc5d m quickly ! ,pilot w deflect ! ,elevator1 :i*1 by ! way1 y see h+$ to ! ,tail4 ,by t means he w =ce ! :ole ,a]oplane to assume a great] ,angle ( ,incid5ce4 ,& ) great] ,angle1 ! ,lift w increase1 ?\gh ,i'm sorry to say ! ,drift w increase also4 ,ow+ to ! great] ,drift1 ! ,spe$ ?r\gh ! air w less51 & ,i'm afraid t won't be helpful to ! ,lift2 b ,i %all n[ be po9t+ upw>ds1 & besides ov]com+ ! ,drift 9 a =w>d direction ,i %all be do+ my be/ to haul ! ,a]oplane skyw>ds4 ,at a c]ta9 angle kn[n z ! ,be/ ,climb+ ,angle1 we %all h our ,maximum ,m>g9 ( ,lift1 & ,i'm hop+ t may be z mu* z almo/ a ?\s& feet altitude a m9ute40 8,!n1 if ! ,pilot is gre51 my *ance w come10 said ! ,maximum ,angle ( ,incid5ce4 8,= if ! ,angle is increas$ ov] ! ,be/ ,climb+ ,angle1 ! ,drift w ru% up2 & ! ,spe$1 & ) x ! ,lift1 w1 :5 my ,angle is rea*$1 drop to a po9t :5 ! latt] w be no m ?an ! ,weight4 ,! ,m>g9 ( ,lift w h entirely disappe>$1 & !re we %all be1 /agg]+ along at my trem5d\s angle1 & only j ma9ta9+ horizontal flight40 8,& !n ) luck ,i'll get my *ance10 said ! ,drift4 8,if he is a bit worse ?an gre51 he'll p]haps /ill fur!r increase ! ,angle4 ,!n ! ,drift1 l>gely increas+1 ! ,spe$1 & consequ5tly ! ,lift1 w become /ill less1 i4e41 less ?an ! ,weight1 & !n--:at price pancakes1#c eh80 8,?ank y10 f ,effici5cy1 8t 0 all mo/ in=m+4 ,& n[ w y tell me1 please1 h[ ! greate/ ,spe$ may be secur$80 8,c]ta9ly1 n[ x's my turn10 pip$ ! ,m9imum ,angle ( ,incid5ce4 8,by means ( ! ,elevator1 ! ,pilot places ! ,a]oplane at my small ,angle1 at :i* ! ,lift only j equals ! ,weight1 &1 also1 at :i* we %all make great] spe$ ) no m ,drift ?an be=e4 ,!n we get our greate/ ,spe$1 j ma9ta9+ horizontal flight40 8,yes2 ?\gh ,i'm out ( ! horizontal & ?ru/+ d[nw>ds10 grumbl$ ! ,propell]1 8& t's n effici5t1 ?\gh ,i suppose x's ! be/ we c d until t ,inv5tor fell[ f9ds 8 ,me*anics40 8,?ank y s mu*10 said ,effici5cy4 8,i ?9k ,i h n[ at any rate an idea ( ! ,elem5t>y ,pr9ciples ( ,flight1 & ,i don't "k t ,i c>e to delve mu* deep]1 = sums always give me a heada*e2 b isn't !re some?+ ab\t ,/ability & ,control8 ,don't y ?9k ,i ought to h a glimm]+ ( !m too80 8,well1 ,i %\ld smile10 said a spruce ,sp>1 :o _h come all ! way f ,am]ica4 8,& t1 z ! ,lectur] says1 w be ! subject ( our next lecture1' s be "h aga9 to-morr[1 & y w be glad to he> t x w be di/9ctly m lively ?an ! subject we h cov]$ to-day40 ,,"p ,,ii4 ,,! ,,pr9ciples1 ,,hav+ ,,settl$ ,,_! ,,diff]5ces1 ,,f9i% ,,! ,,job ,ano!r day _h pass$1 & ! ,flight ,folk _h aga9 ga!r$ toge!r & 7 await+ ! arrival ( ,effici5cy :o1 z usual1 0 r late 9 mak+ an appe>ance4 ,! cr[d 0 l>g] ?an ev]1 & among ! newcom]s "s ( ! mo/ important 7 ! ?ree ,/abilities1 nam$ ,directional1 ,longitud9al1 & ,lat]al1 ) _! assi/ants1 ! ,rudd]1 ,elevator1 & ,ail]ons4 ,!re 0 ,c5trifugal ,=ce1 too1 :o w\ld n sit /ill & creat$ a mo/ unfav\rable impression1 & ,keel-,surface1 ! ,dih$ral ,angle1 & sev]al o!r less] fry4 8,well10 said ,c5trifugal ,=ce1 8,i wi% ?is ,effici5cy ,i've he>d s mu* ab\t w\ld get a move on4 ,sitt+ /ill doesn't agree ) me at all4 ,motion ,i believe 94 ,!re's no?+ l motion--! m ! bett]40 8,we are entirely oppos$ to t10 object$ ! ?ree ,/abilities1 all 9 a brea?4 8,unless x's 9 a p]fectly /raight l9e or a p]fect circle4 ,no?+ b p]fectly /raight l9es or1 ^u occasion1 p]fect circles satisfy u1 & we are /rongly suspici\s ( y\r t5d5cies40 8,well1 we %all see :at we %all see10 said ! ,=ce d>kly4 8,b :o 9 ! "n ( blue sky is ?is80 ,& 9 tripp$ ,effici5cy1 9 a beautifully 8dop$0 dress ( ! late/ fa%ionable %ade ( khaki-col\r$ fabric1 a p]fectly /ream-l9$ bonnet1 & a bewit*+ little ,morane p>asol1#d smil+ z usual1 & airily exclaim+1 8,i'm s sorry ,i'm late1 b y see ! ,design]'s su* a funny man4 ,he objects to sk9 friction1#e & insi/$ ^u me *ang+ my fabric = "o ( a smoo!r surface1 & t delay$ me4 ,de> me1 !re are a lot m ( u to-day1 ar5't !re8 ,i ?9k ,i _h bett] meet "o at a "t40 ,& turn+ to ,directional ,/ability1 %e politely ask$ him :at he pref]r$ to d4 8,my purpose 9 life1 miss10 said he1 8is to keep ! ,a]oplane on its c\rse1 & to a*ieve t !re mu/ be1 9 effect1 m ,keel-,surface beh9d ! ,v]tical ,turn+ ,axis ?an !re is 9 front ( x40 ,effici5cy look+ a little puzzl$1 he add$3 8,j l a wea!rcock1 & by ,keel-,surface ,i mean ev]y?+ y c see :5 y view ! ,a]oplane f ! side ( x--! sides ( ! body1 /ruts1 wires1 etc40 8,oh1 n[ ,i beg9 to see light10 said %e3 8b j exactly h[ does x "w80 8,i'll answ] t10 said ,mom5tum4 8,:5 p]haps by a gu/ ( air ! ,a]oplane is bl[n out ( its c\rse & po9ts 9 ano!r direction1 x doesn't imm$iately fly (f on t new c\rse4 ,i'm s /rong ,i pull x (f ! new c\rse to a c]ta9 ext5t1 & t[>ds ! direction ( ! old c\rse4 ,& s x travels1 z long z my /r5g? la/s1 9 a m or less sideways position40 8,!n10 said ! ,keel-,surface1 8,i get a pressure ( air all on "o side1 & z !re is1 9 effect1 mo/ ( me t[>ds ! tail1 ! latt] gets press$ sideways1 & ! ,a]oplane ?us t5ds to assume its fir/ position & c\rse40 8,i see10 said ,effici5cy1 &1 da9tily hold+ ! ,*alk1 %e approa*$ ! ,blackbo>d4 8,is ?is :at y mean80 8,yes1 t's "r en\gh10 said ! ,keel-,surface1 8& y might rememb]1 too1 t ,i always make ! ,a]oplane nose into ! gu/s r ?an away f !m40 8,if t 0 n ! case10 broke 9 ,lat]al ,/ability1 & affect+ ! fa%ionable ,fly+ ,corps /amm]1 8x w\ld be a h-h-h-o-r-rible affair6 ,if !re 7 too mu* ,keel-,surface 9 front1 !n t gu/ w\ld bl[ ! ,a]oplane r\nd ! o!r way a v consid]able di/ance4 ,& ! "r-h& ,surface be+ on ! outside ( ! turn w\ld h m spe$1 & consequ5tly m ,lift1 ?an ! ,surface on ! o!r side4 ,t means a great] proportion ( ! ,lift on t side1 & be=e y c\ld say ,w>p to ! ,ail]ons ov] ! ,a]oplane w\ld g--probable result a bad side-slip0 8,& :at c ! ,pilot d to save su* a situation z t80 said ,effici5cy4 8,well10 repli$ ,lat]al ,/ability1 8he w try to turn ! ,a]oplane sideways & back to an ev5 keel by means ( w>p+ ! ,ail]ons or little w+s :i* are h+$ on to ! ,w+-tips1 & ab\t :i* y w he> m lat] on2 b if ! side-slip is v bad he may n be able to "r ! ,a]oplane by means ( ! ,ail]ons1 & !n ! only ?+ = him to d is to use ! ,rudd] & to turn ! nose ( ! ,a]oplane d[n & head-on to ! direction ( motion4 ,! ,a]oplane w !n be meet+ ! air 9 ! direction x is design$ to d s1 & ! ,surfaces & also ! controls 7! ,rudd]1 ,ail]ons1 & ,elevator7 w be work+ effici5tly2 b its attitude relative to ! e>? w probably be m or less upside-d[n1 = ! action ( turn+ ! ,a]oplane's nose d[n results1 z y w see by ! illu/ration ,b1 9 ! "r w+1 :i* is on ! outside ( ! circle4 travell+ ?r\gh ! air ) great] spe$ ?an ! left-h& w+4 ,m ,spe$ means m ,lift1 s t results 9 ov]turn+ ! ,a]oplane /ill m2 b n[ x is1 at any rate1 meet+ ! air z x is design$ to meet x1 & ev]y?+ is work+ prop]ly4 ,x is !n only necess>y to w>p ! ,elevator1 z %[n 9 illu/ration ,c1 9 ord] to br+ ! ,a]oplane into a prop] attitude relative to ! e>?40 8,ah60 said ! ,rudd]1 look+ wise1 8x's 9 a case l t :5 ,i become ! ,elevator & ! ,elevator becomes me40 8,t's absurd nons5se10 said ! ,blackbo>d1 8due to loos5ess ( ?\ght & expression40 8,well10 repli$ ! ,rudd]1 8:5 '! ,a]oplane is 9 position ,a & ,i am us$1 !n ,i depress or ,,elevate ! nose ( ! ma*9e2 &1 if ! ,elevator is us$1 !n x turns ! ,a]oplane to "r or left1 :i* is normally my function4 ,surely our roles h *ang$ "o ) ! o!r1 & ,i'm !n ! ,elevator & ! ,elevator is me60 ,said ,lat]al ,/ability to ! ,rudd]1 8,t's altoge!r ! wrong way ( look+ at x1 ?\gh ,i admit0--& ?is r s>ca/ically--8t ! way y put x s\nds r f9e :5 y are talk+ ( y\r exp]i5ces 9 ! air to ^? 'int]e/$ 9 aviation' b kn[+ little ab\t x2 b x won't g d[n "h6 ,y are a ,controll+ ,surface design$ to turn ! ,a]oplane ab\t its v]tical axis1 & ! ,elevator is a ,controll+ ,surface design$ to turn ! ,a]oplane ab\t its lat]al axis4 ,^? are y\r respective jobs1 & y c't possibly *ange !m ab\t4 ,su* talk only leads to confusion1 & ,i hope we %all he> no m ( x40 8,?anks10 said ,effici5cy to ,lat]al ,/ability4 8,& n[1 please1 w y expla9 y\r duties80 8,my duty is to keep ! ,a]oplane horizontal f ,w+-tip to ,w+-tip4 ,fir/ ( all1 ,i sometimes arrange ) ! ,rigg] to wa%-out1 t is decrease1 ! ,angle ( ,incid5ce on "o side ( ! ,a]oplane1 & to effect ! rev]se condition1 if x is n too mu* tr\ble1 on ! o!r side40 8,b10 object$ ,effici5cy1 8! ,lift v>ies ) ! ,angle ( ,incid5ce1 & surely su* a condition w result 9 "o side ( ! ,a]oplane lift+ m ?an ! o!r side8' 8,t's all "r10 said ! ,propell]1 8x's meant to (f-set ! t5d5cy ( ! ,a]oplane to turn ov] sideways 9 ! opposite direction to :i* ,i revolve40 8,t's q cle>1 ?\gh r unexpect$2 b h[ d y c\nt]act ! effect ( ! gu/s :5 !y try to ov]turn ! ,a]oplane sideways80 said %e1 turn+ to ,lat]al ,/ability aga94 8,well10 he repli$1 r mis]ably1 8,i'm n ne>ly s p]fect z ! ,longitud9al & ,directional ,/abilities4 ,! ,dih$ral ,angle--t is1 ! upw>d incl9ation ( ! ,surfaces t[>ds _! w+-tips--does :at x c = me1 b1 9 my op9ion1 x's a m or less futile ef=t4 ,! ,blackbo>d w %[ y ! argum5t40 ,& he at once %[$ !m two ,surfaces1 ea* set at a ,dih$ral ,angle l ?is3 8,please imag9e10 said ! ,blackbo>d1 8t ! top ,v is ! front view ( a ,surface fly+ t[>ds y4 ,n[ if a gu/ bl[s x into ! position ( ! l[] ,v y see t ! horizontal equival5t ( ! ,surface on "o side becomes l>g]1 & on ! o!r side x becomes small]4 ,t results 9 m ,lift on ! l[] side & less on ! high] side1 & if ! ,v is l>ge en\gh x %\ld produce su* a diff]5ce 9 ! ,lift ( "o side to ! o!r z to quickly turn ! ,a]oplane back to its =m] & normal position40 8,yes10 said ! ,dih$ral ,angle1 8t's :at w\ld happ5 if !y w\ld only make me l>ge en\gh2 b !y won't d x because x w\ld too greatly decrease ! horizontal equival5t1 & !re=e ! ,lift1 & incid5tally x w\ld1 z ,a]oplanes are built to-day1 produce an excess ( ,keel ,surface above ! turn+ axis1 & t 9 itself w\ld spoil ! ,lat]al ,/ability4 ,! ,keel ,surface %\ld be equally divid$ above & bel[ ! longitud9al turn+ axis 7^u :i* ! ,a]oplane rolls sideways71 or ! side ^u :i* !re is an excess w get bl[n ov] by ! gu/s4 ,x /rikes me t my future isn't v promis+1 & ab\t my only *ance is :5 ! ,junior ,draughtsman makes a mi/ake1 z he did ! o!r day4 ,& j ?9k ( x1 !y call him a ,design] n[ t he's got a job at ! ,factory6 ,:at did he d8 ,:y1 he calculat$ ! weights wrong & got ! ,c5tre ( ,gravity too high1 & !y didn't discov] x until ! ma*9e 0 built4 ,!n all !y c\ld d 0 to give me a l>g] ,angle4 ,t dropp$ ! bottom ( ! ,v l[] d[n1 & z t's ! c5tre ( ! ma*9e1 :]e all ! ,weight is1 ( c\rse t put ! ,c5tre ( ,gravity 9 its "r place4 ,b n[ !re is too mu* ,keel ,surface above1 & ! :ole ?+'s a ,bad ,compromise1 n at all l ,our ,effici5cy40 ,& ,effici5cy1 blu%+ v prettily at ! complim5t1 !n ask$1 8,& h[ does ! ,c5tre ( ,gravity affect matt]s80 8,t's easy10 said ,gr&fa!r ,gravity4 8,i'm s heavy t if ,i am too l[ d[n ,i act l a p5dulum & cause ! ,a]oplane to roll ab\t sideways1 & if ,i am too high ,i'm l a /ick balanc$ on y\r f+]1 & !n if ,i'm di/urb$1 ov] ,i g & ! ,a]oplane ) me2 &1 9 addition to t1 !re are ! tricks ,i play ) ! ,a]oplane :5 x's bank$ up1#f i4e41 tilt$ sideways = a turn1 & ,c5trifugal ,=ce sets me go+ ! way ,i'm n want$ to g4 ,no2 ,i get on be/ ) ,lat]al ,/ability :5 my ,c5tre is "r on ! c5tre ( ,drift1 or1 at any rate1 n mu* bel[ x40 ,& ) t he settl$ back into ! ,lectur]'s ,*air & w5t s\nd asleep aga91 = he 0 s v1 v old1 9 fact ! fa!r ( all ! ,pr9ciples4 ,& ! ,blackbo>d _h be5 busy1 & n[ %[$ !m a picture ( ! ,a]oplane z f> z !y knew x1 & y w see t !re is a slight ,dih$ral ,angle1 & also1 fix$ to ! tail1 a v]tical ,keel ,surface or f91 z is v (t5 ! case 9 ord] to ensure ! great] effect ( su* surface be+ beh9d ! v]tical turn+ axis4 ,b ,effici5cy1 gr[+ r critical ) h] newly ga9$ k1 cri$ out3 8,b :]e's ! horizontal ,tail ,surface8 ,x doesn't look "r l t60 8,?is is :5 ,i h ! pleasure ( meet+ y1 my de>10 said ,longitud9al ,/ability4 8,"h's ! ,tail ,surface10 he said1 8& 9 ord] to help me x mu/ be set ,,9 ,,effect at a mu* less ,angle ( ,incid5ce ?an ! ,ma9 ,surface4 ,to expla9 we mu/ tr\ble ! ,blackbo>d aga910 & ?is 0 8 ef=t3 8,i h tri$ to make t z cle> z possible10 he said4 8,x may appe> a bit complicat$ at fir/1 b if y w take ! tr\ble to look at x = a m9ute y w f9d x q simple4 ,a is ! normal & prop] direction ( motion ( ! ,a]oplane1 b1 ow+ to a gu/ ( air1 x takes up ! new nose-d[n position4 ,ow+ to ,mom5tum1 h[ev]1 x does n fly /raight along 9 t direction1 b moves m or less 9 ! direction ,b1 :i* is ! resultant ( ! two =ces1 ,mom5tum & ,?ru/4 ,& s y w note t ! ,angle ( ,incid5ce1 :i* is ! incl9ation ( ! ,surfaces to ! ,direction ( ,motion1 has decreas$1 & ( c\rse ! ,lift decreases ) x4 ,y w also see1 & ?is is ! po9t1 t ! ,tail ,surface has lo/ a high] proportion ( its ,angle1 & consequ5tly its ,lift1 ?an has ! ,ma9 ,surface4 ,!n1 su* be+ ! case1 ! ,tail mu/ fall & ! ,a]oplane assume its normal position aga91 ?\gh probably at a slightly l[] altitude40 8,i'm afraid ,i'm v /upid10 said ,effici5cy1 8b please tell me :y y lay /ress ^u ! words ',,9 ,,effect4'0 8,ah6 ,i 0 wond]+ if y w\ld spot t10 he repli$4 8,& !re is a v good reason = x4 ,y see1 9 "s ,a]oplanes ! ,tail ,surface may be actually set at ! same ,angle on ! ma*9e z ! ,ma9 ,surface1 b ow+ to ! air be+ deflect$ d[nw>ds by ! front ,ma9 ,surface x meets ! ,tail ,surface at a less] angle1 & inde$ 9 "s cases at no angle at all4 ,! ,tail is !n = its surface gett+ less ,lift ?an ! ,ma9 ,surface1 al?\gh set at ! same angle on ! ma*9e4 ,x may !n be said to h ,,9 ,,effect a less ,angle ( ,incid5ce4 ,i'll j %[ y on ! ,blackbo>d40 8,& n[10 said ,effici5cy1 8,i h only to meet ! ,ail]ons & ! ,rudd]1 hav5't ,i80 8,"h we are10 repli$ ! ,ail]ons1 or little w+s4 8,please h+e u on to ! back ( ! ,ma9 ,surfaces1 "o ( u at ea* ,w+-tip1 & jo9 u up to ! ,pilot's joy/ick by means ( ! control cables4 ,:5 ! ,pilot wi%es to tilt ! ,a]oplane sideways1 he w move ! /ick & depress u ^u "o side1 ?us giv+ u a l>g] ,angle ( ,incid5ce & s creat+ m ,lift on t side ( ! ,a]oplane2 &1 by means ( a cable connect+ u ) ! ,ail]ons on ! o!r side ( ! ,a]oplane1 we %all1 z we are depress$1 pull !m up & give !m a rev]se or negative ,angle ( ,incid5ce1 & t side w !n get a rev]se ,lift or d[nw>d ?ru/1 & s we are able to tilt ! ,a]oplane sideways4 8,& we "w be/ :5 ! ,angle ( ,incid5ce ( ! ,surface 9 front ( u is v small1 = :i* reason x is sometimes decreas$ or wa%$-out t[>ds ! ,w+-tips4 ,! reason ( t is t by ! "t ! air rea*es u x has be5 deflect$ d[nw>ds--! great] ! ,angle ( ,incid5ce ! m x is driv5 d[nw>ds--& 9 ord] = u to secure a ,reaction f x1 we h to take su* a l>ge ,angle ( ,incid5ce t we produce a poor proportion ( ,lift to ,drift2 b ! small] ! ,angle ( ! ,surface 9 front ( u ! less ! air is deflect$ d[nw>ds1 & consequ5tly ! less ,angle is requir$ ( u1 & ! bett] our proportion ( ,lift to ,drift1 :i*1 ( c\rse1 makes u mu* m effective ,controls40 8,yes10 said ! ,lat]al & ,directional ,/abilities 9 "o voice1 8t's s1 & ! wa%-out helps u also1 = !n ! ,surfaces t[>ds _! ,w+-tips h less ,drift or ',head-,resi/ance1' & consequ5tly ! gu/s w affect !m & u less2 b su* decreas$ ,angle ( ,incid5ce means decreas$ ,lift z well z ,drift1 & ! ,design] does n always c>e to pay ! price40 8,well10 said ! ,ail]ons1 8if x's n done x w mean m "w = ! ,rudd]1 & t won't please ! ,pilot40 8,:atev] d y mean80 ask$ ,effici5cy4 8,:at c ! ,rudd] h to d ) y80 8,x's l ?is10 !y repli$3 8:5 we are deflect$ d[nw>ds we ga9 a l>g] ,angle ( ,incid5ce & also ent] an area ( compress$ air1 & s produce m ,drift ?an ^? ( u on ! o!r side ( ! ,a]oplane1 :i* are deflect$ upw>ds into an area ( r>efi$ air due to ! ,,suction effect 7?\gh t t]m is n academically correct7 on ! top ( ! ,surface4 ,if !re is m ,drift1 i4e41 ,resi/ance1 on "o side ( ! ,a]oplane ?an on ! o!r side1 !n ( c\rse x w turn (f its c\rse1 & if t diff]5ce 9 ,drift is s]i\s1 z x w v likely be if !re is no wa%-out1 !n x w mean a good deal ( "w = ! ,rudd] 9 keep+ ! ,a]oplane on its c\rse1 besides creat+ extra ,drift 9 do+ s40 8,i ?9k1 !n10 said ,effici5cy1 8,i %\ld pref] to h t wa%-out1#g & my fri5d ! ,design] is s clev] at produc+ /r5g? ( con/ruction = light weight1 ,i'm pretty sure he won't m9d pay+ ! price 9 ,lift4 ,& n[ let me see if ,i c sket* ! complet$ ,a]oplane40 8,well1 ,i hope t's all z x %\ld be10 %e conclud$1 8= to-morr[ ! ,great ,te/ 9 ! air is due40 ,,"p ,,iii4 ,,! ,,great ,,te/ ,x is five o'clock ( a f9e calm morn+1 :5 ! ,a]oplane is :eel$ out ( its %$ on to ! gre5sw>d ( ! ,milit>y ,a]odrome4 ,!re is e promise ( a good fly+ day1 &1 al?\gh ! sun has n yet ris51 x is light en\gh to disc]n ! motionless lay] ( fleecy cl\ds "s five ?\s& feet high1 & f>1 f> above t a few filmy mottl$ /reaks ( vap\r4 ,j ! k9d ( morn+ belov$ ( pilots4 ,a br& new1 raki%1 up-to-date ma*9e x is1 ( highly poli%$1 beautifully f9i%$ wood1 fabric z tight z a drum1 poli%$ metal1 & e "p s p]fectly 8/reaml9$0 to m9imize ,drift1 :i* is ! resi/ance ( ! air to ! passage ( ! ma*9e1 t to ! v]ie/ tyro ! rem>k ( ! ,pilot is obvi\sly ju/ifi$4 8,clean look+ 'bus1 looks almo/ alive & impati5t to be (f4 ,ought to h a turn = spe$ ) ^? l9es40 8,yes10 replies ! ,flight-,comm&]1 8x's ! late/ ( its type & looks a beauty4 ,give x a good te/4 ,a special report is requir$ on ?is ma*9e40 ,! ,a4,m4's#h h n[ plac$ ! ,a]oplane 9 position fac+ ! g5tle air t is j beg9n+ to make itself evid5t2 ! eng9e ,fitt]1 hav+ made sure ( a suffici5cy ( oil & petrol 9 ! tanks1 is /&+ by ! ,propell]2 ! ,rigg]1 satisfi$ ) a job well done1 is critically 8vett+0 ! ma*9e by eye1 f\r ,a4,m4's are at _! po/s1 ready to hold ! ,a]oplane f jump+ ! blocks :i* h be5 plac$ 9 front ( ! :eels2 & ! ,flight-,s]geant is await+ ! ,pilot's ord]s4 ,z ! ,pilot approa*es ! ,a]oplane ! ,rigg] spr+s to att5tion & reports1 8,all correct1 sir10 b ! ,fitt] does n ?is morn+ report ! condition ( ! ,eng9e1 = well he kn[s t ?is ,pilot always p]sonally looks aft] ! prelim9>y eng9e te/4 ,! latt]1 9 lea!rn kit1 w>m fly+ boots & goggl$1 climbs into 8 seat1 & n[1 ev5 m ?an be=e1 has ! ,a]oplane an almo/ liv+ appe>ance1 z if /ra9+ to be (f & away4 ,fir/ he moves ! ,controls to see t ev]y?+ is cle>1 = sometimes :5 ! ,a]oplane is on ! gr\nd ! control lev] or 8joy-/ick0 is la%$ fa/ to prev5t ! w9d f bl[+ ! controll+ surfaces ab\t & possibly damag+ !m4 ,! air ( ?is e>ly dawn is di/9ctly *illy1 & ! ,a4,m4's are beg9n+ to /amp _! cold feet ^u ! dewy grass1 b v c>eful & circumspect is ! ,pilot1 z he mutt]s to himself1 8,don't worry & flurry1 or y'll die 9 a hurry40 ,at la/ he fumbles = 8 safety belt1 b ) a />t rememb]s ! ,pilot ,air ,spe$ ,indicator1 &1 adju/+ x to z]o1 smiles z he he>s ! ,pilot-head's gruff voice1 8,well1 ,i %\ld ?9k s1 tw5ty miles an h\r ,i 0 regi/]+4 ,t's likely to cause a gre5 pilot to /all ! ,a]oplane4 ,pancake1 !y call x40 ,& ! ,pilot1 :o is an old h& & has le>n$ a lot ( ?+s 9 ! air t m]e e>?-dwell]s "k no?+ ab\t1 di/9ctly he>d ! ,pilot ,tube1 ^: m\? is op5 to ! air to receive its pressure1 /amm]4 8,oh ,lor6 ,i've got an e>wig already--hope to goodness ! ,rigg] bl[s me out :5 ,i come d[n--& ?is morn+ air simply fills me ) moi/ure2 ,i'll nev] keep ! ,liquid /eady 9 ! ,gauge4 ,i'm n sure ( my rubb] connections ei!r40 8,oh1 %ut up60 cry all ! ,wires 9 unison1 8hav5't we got our tr\bles too8 ,we're 9 ! mo/ horrible /ate ( t5sion4 ,x's simply murd]+ our ,factor ( ,safety1 & h[ we c possibly /& x :5 we get ! ,lift only ! ,design] kn[s40 8,t's all "r10 squeak all ! little ,wire loops1 8we're t accommodat+1 we're sure to elongate a bit & s relieve y\r t5sion40 ,= ! :ole ,a]oplane is brac$ toge!r ) innum]able wires1 _m ( :i* are at _! ends b5t ov] 9 ! =m ( loops 9 ord] to connect ) ! metal fitt+s on ! sp>s & else:]e--*eap & easy way ( mak+ connection4 8,elongate1 y little devils1 w\ld y80 fairly %\t ! ,angles ( ,incid5ce1 ,dih$ral & ,/agg]1 amid a *orus ( groans f all p>ts ( ! ,a]oplane4 8,:at's go+ to happ5 to u !n8 ,h[ are we go+ to keep our adju/m5ts ^u :i* good fly+ dep5ds80 8,butt u & screw u10#i wail ! ,wires4 8,butt u & screw u1 & dea? to ! ,loops4 ,t's :at we sang to ! ,design]1 b he only look$ sad & sc[l$ at ! ,directors40 8,& :o on e>? are !y80 ask$ ! ,loops1 trembl+ = _! tr\blesome little lives4 8,oh e>? inde$10 sniff$ ,effici5cy1 :o _h n spok5 be=e1 hav+ be5 r5d]$ r %y by be+ badly compromis$ 9 ! ,draw+ ,(fice4 8,i'd l to get "s ( !m up betwe5 ,heav5 & ,e>?1 ,i w\ld4 ,i'd give 'em some?+ to ?9k ( besides _! ,debits & ,cr$its--b all ! same ! ,design] w get 8 way 9 ! end4 ,i'm 8 ,be/ ,girl1 y "k1 & if we c\ld only get rid ( ! ,directors1 ! little ,t9 god1 & ! ,man-:o-takes-!-cr$it1 we %\ld be q happy40 ,!n %e abruptly subsides1 feel+ t p]haps ! less said ! bett] until %e has made a reputation 9 ! ,air4 ,! matt] ( t ,compromise /ill rankl$1 & inde$ x does seem h>dly fit t a bold bad ,t9 god %\ld flirt ) ,effici5cy4 ,y see !re 0 a little ,t9 god1 & he said 8,boom1 ,boom ,,boom6 ,nons5se6 ,x ,,mu/ be done10 & ?+s l t 9 a v l\d voice1 & ! ,design] tore 8 hair & 0 furi\s1 b ! ,directors1 :o 7 ?9k+ ( no?+ b ,ord]s & ,divid5ds1 _h ! :ip-h& ( ,,him1 & s !re y are1 & s poor beautiful ,miss ,effici5cy 0 compromis$4 ,all ?is "t ! ,pilot is c>efully buckl+ 8 belt & mak+ himself p]fectly easy & com=table1 z all good pilots d4 ,z he /raight5s himself up f a c>eful inspection ( ! ,deviation ,curve#aj ( ! ,compass & takes comm& ( ! ,controls1 ! ,?rottle & ! ,ignition1 ! voices gr[ fa9t] & fa9t] until !re is no?+ b a trembl+ ( ! ,lift & ,drift wires to indicate to 8 und]/&+ eye _! /ate ( t5sion 9 expectancy ( ! ,great ,te/4 8,petrol on80 %\ts ! ,fitt] to ! ,pilot4 8,petrol on10 replies ! ,pilot4 8,ignition (f80 8,ignition (f40 ,r\nd goes ! ,propell]1 ! ,eng9e suck+ 9 ! ,petrol ,vap\r ) satisfi$ gulps4 ,& !n-- 8,contact80 f ! ,fitt]4 8,contact10 says ! ,pilot4 ,n[ "o sw+ ( ! ,propell] by ! ,fitt]1 & ! ,eng9e is awake & work+4 ,sl[ly at fir/ ?\gh1 & 9 a weak voice dem&+1 8,n too mu* ,?rottle1 please4 ,i'm v cold & mu/n't run fa/ until my ,oil has ?9n$ & is circulat+ freely4 ,?ree m9utes sl[ly1 z y love me1 ,pilot40 ,fa/] & fa/] turn ! ,eng9e & ,propell]1 & ! ,a]oplane1 trembl+ 9 all its p>ts1 /ra9s to jump ! blocks & be (f4 ,c>efully ! ,pilot li/5s to :at ! ,eng9e ,revolution ,indicator says4 ,at la/1 8,/eady at #a1ejj revs4 & ,i'll pick up ! re/ 9 ! ,air40 ,!n does he ?rottle d[n ! ,eng9e1 c>efully putt+ ! lev] back to ! la/ not* to make sure t 9 su* position ! ,?rottle is /ill suffici5tly op5 = ! ,eng9e to cont9ue work+1 z o!rwise x might lead to him 8los+0 8 ,eng9e 9 ! air :5 ?rottl+ d[n ! p[] = desc5t4 ,!n1 giv+ ! (ficial signal1 he sees ! blocks remov$ f ! :eels1 & ! ,flight-,s]geant salut+ he kn[s t all is cle> to asc5d4 ,"o m signal1 & all ! ,a4,m4's run cle> ( ! ,a]oplane4 ,!n g5tly1 g5tly m9d y1 ) none ( ! 8cra%+ on0 bad ,pilots ?9k s f9e1 he op5s ! ,?rottle &1 ! ,propell] ,?ru/ ov]com+ its enemy ! ,drift1 ! ,a]oplane moves =w>d4 8,ah60 says ! ,w9d-scre51 8t's ,discipl9e1 t is4 ,?r\gh my little w9d[ ,i see mo/ ?+s1 & don't ,i j "k t poor discipl9e always results 9 poor "w 9 ! air1 & don't y =get x40 8,discipl9e is x80 compla9s ! ,"u-c>riage1 z its :eels roll swiftly ov] ! r r\gh gr\nd4 8,i'm bump gett+ x2 & bump1 bump1 all ,i want1 bang1 bump1 rattle1 too60 ,b1 z ! ,lift increases ) ! ,spe$1 ! compla9ts ( ! ,"u-c>riage are /ill$1 & !n1 ! fri5dly ,lift becom+ great] ?an ! ,weight1 ! ,a]oplane swiftly & easily takes to ! air4 ,bel[ is left ! ,e>? ) all its bumps & tr\bles4 ,up into ! clean cle> ,air moves ) incr$ible spe$ & /ead9ess ?is triumph ( ! ,design]1 ! result ( h[ mu* m5tal ef=t1 imag9ation1 trials & errors1 failures & successes1 & _m a life lo/ 9 high endeav\r4 ,n[ is ! mighty voice ( ! ,eng9e he>d z he turns ! ,propell] n9e hundr$ times a m9ute4 ,n[ does ! ,?ru/ fight ! ,drift = all x's wor?1 & ! ,air ,spe$ ,indicator gasps ) delight1 8,"o hundr$ miles an h\r60 ,& n[ does ! burd5 ( "w fall ^u ! ,lift & ,drift ,wires1 & !y scream to ! ,turnbuckles ^: bus9ess x is to hold !m 9 t5sion1 8,?is is ! limit6 ! ,limit6 ,,! ,,limit6 ,release u1 if only a qu>t] turn40 ,b ! ,turnbuckles are lock$ too fa/ to turn _! eyes or utt] a ^w4 ,only ! ,lock+ ,wires ?us3 8,ha6 ha6 ! ,rigg] knew 8 job4 ,he knew ! trick1 & !re's no release "h40 ,= an exp]t rigg] w always use ! lock+ wire 9 su* a way z to oppose ! slighte/ t5d5cy ( ! turnbuckle to unscrew4 ,! o!r k9d ( rigg] w (t5 use ! wire 9 su* a way z to all[ ! turnbuckle1 to ! 8eyes0 ( :i* ! wires are atta*$1 to unscrew a qu>t] ( a turn or m1 ) ! result t ! correct adju/m5t ( ! wires may be lo/2 & ^u _! f9e adju/m5t mu* dep5ds4 ,& ! ,/ruts & ! ,sp>s groan 9 compression & pray to keep /raight1 = once 8out ( tru?0 !re is1 9 addition to possible collapse1 ! c]ta9ty t 9 b5d+ !y w ?r[ _m wires out ( adju/m5t4 ,& ! ,fabric's q mix$ 9 its m9d1 & ejaculates1 8,n[1 :o w\ld h ?\ght ,i got m ,lift f ! top ( ! ,surface ?an its bottom80 ,& !n trucul5tly to ! ,di/ance ,pieces1 :i* run f rib to rib1 8,j keep ! ,ribs f roll+1 w y8 or y'll see me /rip4 ,i'm an ,iri%man1 ,i am1 & if my coat comes (f---- ,yes1 ,iri%1 ,i said4 ,i us$ to come f ,egypt1 b ,i've got naturaliz$ s9ce ! ,w> began40 ,!n ! ,air ,spe$ ,indicator cat*es ! eye ( ! ,pilot4 8,good en\gh10 he says z he g5tly deflects ! ,elevator & po9ts ! nose ( ! ,a]oplane upw>ds 9 se>* ( ! elusive ,be/ ,climb+ ,angle4 8,ha6 ha60 %\ts ! ,drift1 gr[+ /rong] ) ! increas$ ,angle ( ,incid5ce4 8,ha6 ha60 he laughs to ! ,?ru/4 8,n[ ,i've got y4 ,n[ :o's ,ma/]80 ,& ! ,propell] %rieks hy/]ically1 8,oh6 look at me4 ,i'm a helicopt]4 ,t's n fair4 ,:]e's ,effici5cy80 ,& %e c only sadly reply1 8,yes1 inde$1 b y see we're a ,compromise40 ,& ! ,drift has hopes ( rea*+ ! ,maximum ,angle ( ,incid5ce & vanqui%+ ! ,?ru/ & ! ,lift4 ,& he gr[s v bold z he /rangles ! ,?ru/2 b ! situation is sav$ by ! ,propell]1 :o is n[ bravely helicopt+ skyw>ds1 some:at to ! *agr9 ( ,effici5cy4 8,mu* ado ab\t no?+10 quotes ! ,a]oplane le>n$ly4 8,compromise or n1 ,i'm climb+ a ?\s& feet a m9ute4 ,ask ! ,altimet]4 ,he'll confirm x40 ,& s inde$ x 04 ,! vacuum box ( ! ,altimet] 0 /eadily exp&+ "u ! decreas$ pressure ( ! r>efi$ air1 & by means ( its little lev]s & its wond]ful *a9 no l>g] ?an a hair x 0 mov+ ! ne$le r\nd ! gauge & indicat+ ! asc5t at ! rate ( a ?\s& feet a m9ute4 ,& lo6 ! ,a]oplane has almo/ rea*$ ! cl\ds6 ,b :at's ?is8 ,a sudd5 gu/1 & d[n s9ks "o w+ & up goes ! o!r4 8,oh1 my ,horizontal ,equival5t60 despair+ly call ! ,planes3 8x's elop+ ) ! ,lift1 & :at 9 ! "n ( ,gravity w happ58 ,surely !re 0 en\gh sc&al 9 ! ,factory )\t ?is1 too60 ,= ! lift v>ies ) ! horizontal equival5t ( ! planes1 s t if ! a]oplane tilts sideways beyond a c]ta9 angle1 ! lift becomes less ?an ! weight ( ! ma*9e1 :i* mu/ !n fall4 ,a fall 9 su* a position is kn[n z a 8side-slip40 ,b ! ev]-wat*ful ,pilot in/antly depresses "o ail]on1 elevat+ ! o!r1 ) j a t\* ( ! rudd] to keep on ! c\rse1 & ! ,planes welcome back _! preci\s ,lift z ! ,a]oplane flicks back to its normal position4 8,bit bumpy "h "u ^! cl\ds10 is all ! ,pilot says z he heads = a gap betwe5 !m1 & ! next m9ute ! ,a]oplane %oots up into a new _w ( space4 8,my eye60 ejaculates ! ,w9d-scre51 8talk ab\t a view60 ,& inde$ m]e words w always fail to express ! wond] ( x4 ,six ?\s& feet up n[1 & look6 ,! sun is ris+ quick] ?an ev] mortal on e>? witness$ its asc5t4 ,f> bel[ is ,"m ,e>?1 wrapt 9 mi/s & deep blue %ad[s1 & f> above are ^? light1 filmy1 e!real cl\ds n[ fa9tly t+$ ) p9k ,& all ab\t great m\nta9s ( cl\d1 lazily float+ 9 space4 ,! sun rises & !y take on all col\rs1 bl5d+ "o ) ! o!r1 f dazzl+ :ite to crimson & deep violet-blue4 ,lakes & riv]s "h & !re 9 ! enorm\s expanse ( c\ntry bel[ refract ! level rays ( ! sun &1 l s _m imm5se diamonds1 s5d dazzl+ %afts ( light f> upw>ds4 ,! tops ( ! hills n[ laugh to ! light ( ! sun1 b ! valleys are /ill my/]i\s d>k blue cav]ns1 cl[n$ ) :ite filmy lace-l /reaks ( vap\r4 ,& )al ! increas+ s5se ) altitude ( va/1 clean1 sil5t solitudes ( space4 ,lives !re ! man :o c adequately describe ?is ,wond]8 8,nev]10 says ! ,pilot1 :o has se5 x _m times1 b to :om x is ev] new & m wond]ful4 ,up1 up1 up1 & /ill up1 unfalt]+ly spe$s ! ,pilot & 8 m\nt4 ,sweet ! drone ( ! ,eng9e & /eady ! ,?ru/ z ! ,propell] exult+ly battles ) ! ,drift4 ,& look6 ,:at is t bright silv] /reak all along ! horizon8 ,x puzzl$ ! ,pilot :5 fir/ he saw x1 b n[ he kn[s x = ! ,sea1 full fifty miles away6 ,& on 8 "r is ! brightness ( ! ,morn & ! smil+ ,e>? unveil+ itself to ! ard5t rays ( ! ,sun2 & on 8 left1 s high is he1 !re is yet black ,night1 hid+ innum]able ,cities1 ,t[ns1 ,villages & all ^? places :]e soon teem+ multitudes ( m5 %all awake1 & by _! unceas+ toil & ! _s )9 !m produce m>vels ( :i* ! ,a]oplane is b ! h>b+]4 ,& ! ,pilot's s\l is refre%$1 & 8 vision1 n[ exalt$1 sees ! ,e>? a v g>d51 ev5 z x appe>s at t height1 ) discord bani%$ & a happy "t come1 :5 ! ,design] %all h at la/ captur$ ,effici5cy1 & ! ,man-:o-takes-!-cr$it is he :o has e>n$ x1 & :5 kisses are ! only ?+s t g by fav\r4 ,n[ ! ,pilot anxi\sly scans ! ,b>ograph1 :i* is an in/rum5t mu* ! same z ! ,altimet]2 b 9 ?is case ! expansion ( ! vacuum box causes a p5 to trace a l9e ^u a roll ( pap]4 ,?is pap] is made by clockwork to pass ov] ! po9t ( ! p51 & s a curv$ l9e is made :i* accurately regi/]s ! spe$ ( ! asc5t 9 feet p] m9ute4 ,no long] is ! asc5t at ! rate ( a ?\s& feet a m9ute1 & ! ,propell] compla9s to ! ,eng9e1 8,i'm los+ my ,revs4 & ! ,?ru/4 ,buck up ) ! ,p[]1 = ! ,lift is decreas+1 ?\gh ! ,weight rema9s mu* ! same40 ,quo? ! ,eng9e3 8,i /rangle = ,air4 ,a c]ta9 proportion1 & t ( "r d5sity1 ,i mu/ h to "o "p ( ,petrol1 9 ord] to give me full p[] & compression1 & "h at an altitude ( t5 ?\s& feet ! ,air is only two-?irds z d5se z at sea-level4 ,oh1 :]e is he :o w inv5t a contrivance to keep me suppli$ ) ,air ( "r d5sity & quality8 ,x %\ld n be impossible )9 c]ta9 limits40 8,we fully agree10 said ! dy+ ,p[] & ,?ru/4 8,only ma9ta9 ,u & y %all be surpris$ at ! result4 ,= our enemy ,drift decreases 9 respect ( di/ance ) ! increase ( altitude & r>ity ( air1 & !re is no limit to ! spe$ ?r\gh space if only our /r5g? rema9s4 ,& ) oxyg5 = ,pilot & ,pass5g]s & a /eep] pit*#aa = ! ,propell] we may !n circle ! ,e>? 9 a day60 ,ah1 ,read]1 smile n unbeliev+ly1 z y smil$ b a few ye>s pa/4 ,!re may be great] wond]s yet4 ,consid] t z ! spe$ increases1 s does ! mom5tum or /or$-up =ce 9 ! mass ( ! a]oplane become t]rific4 ,&1 be>+ t 9 m9d1 rememb] t ) altitude gravity decreases4 ,!re may yet be lit]ally o!r worlds to conqu]4#ab ,n[ at fifte5 ?\s& feet ! conditions are *illy & r>e1 & ! ,pilot1 ) ?\ghts ( breakfa/ f> bel[1 exclaims1 8,high en\gh6 ,i _h bett] get on ) ! ,te/40 ,& !n1 z he depresses ! ,elevator1 ! ,a]oplane ) relief assumes its normal horizontal position4 ,!n1 almo/ clos+ ! ,?rottle1 ! ,?ru/ dies away4 ,n[1 ! nose ( ! ,a]oplane %\ld s9k ( its own volition1 & ! craft glide d[nw>d at fly+ spe$1 :i* is 9 ?is case a hundr$ miles an h\r4 ,t is :at %\ld happ5 if ! ,design] has c>efully calculat$ ! weight ( e "p & arrang$ = ! c5tre ( gravity to be j ! "r di/ance 9 front ( ! c5tre ( lift4 ,?us is ! ,a]oplane 8nose-heavy0 z a glid]1 & j s to a degree ensur+ a spe$ ( glide equal to its fly+ spe$4 ,& ! ,air ,spe$ ,indicator is /eady at "o hundr$ miles an h\r1 & 8,t's all "r60 exclaims ! ,pilot4 8,& v useful1 too1 9 a fog or a cl\d10 he reflects1 = !n he c safely leave ! angle ( ! glide to itself1 & give all 8 att5tion1 & he w ne$ x all1 to keep+ ! ,a]oplane horizontal f w+-tip to w+-tip1 & to keep+ x /raight on its c\rse4 ,! latt] he w manage ) ! rudd]1 controll$ by 8 feet1 & ! ,compass w tell him :e!r a /raight c\rse is kept4 ,! =m] he w control by ! ,ail]ons1 or little w+s h+$ to ! tips ( ! planes1 & ! bubble 9 ! ,incl9omet] 9 front ( him mu/ be kept 9 ! middle4 ,a ,pilot1 be+ only human1 may be able to d two ?+s at once1 b ?ree is a tall ord]1 s 0 ?is ,pilot reliev$ to f9d ! ,design n at fault & 8 craft a 8natural glid]40 ,to correct ?is nose-heavy t5d5cy :5 ! ,eng9e is runn+1 & desc5t n requir$1 ! c5tre ( ,?ru/ is arrang$ to be a little bel[ ! c5tre ( ,drift or ,resi/ance1 & ?us acts z a c\nt]-balance4 ,b :at is ?is /ream ( bad language f ! ,exhau/ ,pipe1 accompani$ by g\ts ( smoke & vap\r8 ,! ,eng9e1 n[ revolv+ at no m ?an "o-t5? its normal spe$1 has upset ! proportion ( petrol to air1 & combu/ion is tak+ place int]mitt5tly or 9 ! ,exhau/ ,pipe1 :]e x has no bus9ess to be4 8,cra%1 ,bang1 ,rattle----6----6----60 & worse ?an t1 yells ! ,exhau/1 & ! ,a]oplane1 :o is a g5tleman & n a box kite1#ac remon/rates ) ! sev]ity ( a ,s5ior ,(fic]4 8,see ! ,m$ical ,(fic]1 y "y ,hun4 ,g & see a doctor4 ,vocal di>rhoea1 t's y\r compla9t1 & a v na/y "o too4 ,bad =m1 bad = discipl9e1 & a nuisance 9 ! ,mess4 ,:at's y\r ,regim5t8 ,special ,res]ve1 y say8 ,humph6 ,s\nds l ,secondh& ,bicycle ,trade to me60 ,n[ ! ,pilot decides to *ange ! /raight glid+ desc5t to a spiral "o1 &1 ob$i5t to ! ,rudd]1 ! ,a]oplane turns to ! left4 ,b ! ,mom5tum 7two tons at #ajj miles p] h\r is no small affair7 heavily res5ts ?is *ange ( direction1 & tries its level be/ to prev5t x & to pull ! ma*9e sideways & outw>ds f its spiral c\rse--t is1 to make x 8side-skid0 outw>ds4 ,b ! ,pilot deflects ! ,ail]ons & 8banks0 up ! planes to ! correct angle1 &1 ! ,a]oplane skidd+ sideways & outw>ds1 ! l[e/ surfaces ( ! planes press up aga9/ ! air until ! pressure equals ! c5trifugal =ce ( ! ,mom5tum1 & ! ,a]oplane spirals /eadily d[nw>ds4 ,d[n1 d[n1 d[n1 & ! air gr[s d5s]1 & ! ,pilot gulps l>gely1 fill+ 8 lungs ) ! heavi] air to c\nt]act ! increas+ pressure f )\t4 ,d[n ?r\gh a gap 9 ! cl\ds1 & ! ,a]odrome spr+s into view1 appe>+ no l>g] ?an a sauc]1 & ! ,pilot1 hav+ by n[ got ! 8feel0 ( ! ,controls1 proce$s to put ! ,a]oplane ?r\gh its paces4 ,fir/ at its ,maximum ,angle1 /agg]+ along tail-d[n & j ma9ta9+ horizontal flight2 !n a dive at f> ov] fly+ spe$1 f9i%+ ) a p]fect loop2 !n %>p turns ) att5dant v]tical 8banks0 & !n a wond]ful swit*back flight1 spe$+ d[n at a hundr$ & fifty miles an h\r ) %ort1 exhil>at+ asc5ts at ! rate ( two ?\s& feet a m9ute6 ,all ! p>ts are n[ work+ well toge!r4 ,su* wires z 7 be=e 9 undue t5sion h secur$ relief by slightly elongat+ _! loops1 & ea* "o is n[ do+ its bit1 & all are %>+ ! burd5 ( "w toge!r4 ,! ,/ruts & ! ,sp>s1 :i* felt s awkw>d at fir/1 h b$d$ !mselves 9 _! sockets1 & are tak+ ! compression /resses uncompla9+ly4 ,! ,control ,cables ( twi/$ wire1 a bit tight be=e1 h slightly l5g!n$ by p]haps ! eigh? ( an in*1 &1 ! ,controls in/antly respond+ to ! delicate t\* ( ! ,pilot1 ! ,a]oplane1 at ! w ( its ,ma/]1 d>ts ?is way & t way1 dives1 loops1 spirals1 & at la/1 9 "o long1 magnific5t glide1 l&s g5tly 9 front ( its %$4 8,well1 :at result80 calls ! ,flight-,comm&] to ! ,pilot4 8,a hundr$ miles an h\r & a ?\s& feet a m9ute10 he briefly replies4 8,& a v good result too10 says ! ,a]oplane1 complac5tly1 z he is c>efully :eel$ into 8 %$4 ,t is ! way ,a]oplanes speak to ^? :o love !m & und]/& !m4 ,lots ( ,pilots "k all ab\t x1 & c sp9 y wond]ful y>ns1 mu* bett] ?an ?is "o1 if y cat* !m 9 a confid5tial mood--on leave1 = in/ance1 & aft] a good d9n]4 ,,"p ,,iv4 ',,cross ,,c\ntry ,! ,a]oplane _h be5 design$ & built1 & te/$ 9 ! air1 & n[ /ood on ! ,a]odrome ready = its fir/ 'cross-c\ntry flight4 ,x _h run ! gauntlet ( pseudo-design]s1 crank inv5tors1 press 8exp]ts10 & politicians2 ( manufactur]s ke5 on *eap "w & l>ge pr(its2 ( poor pilots :o _h funk$ x1 & good pilots :o _h expect$ too mu* ( x4 ,?\s&s ( p\nds _h be5 wa/$ on x1 _m _h gone bankrupt ov] x1 & o!rs x _h provid$ ) safe fat jobs4 ,someh[1 & despite e conceivable ob/acle1 x _h manag$ to muddle ?r\gh1 & n[ x 0 ready = its "w4 ,x 0 n p]fect1 = !re 7 fifty diff]5t ways 9 :i* x might be improv$1 "s ( !m %amefully obvi\s4 ,b x 0 fairly s\nd me*anically1 _h a little inh]5t /ability1 0 easily controll$1 c\ld climb a ?\s& feet a m9ute1 & its spe$ 0 a hundr$ miles an h\r4 ,9 %ort1 q a cr$itable ma*9e1 ?\gh ( c\rse ! "r man _h n got ! cr$it4 ,x is r\gh1 unsettl$ wea!r ) a ?irty mile an h\r w9d on ! gr\nd1 & t means fifty m or less al(t4 ,lots ( cl\ds at diff]5t altitudes to bo!r ! ,pilot1 & ! air none to cle> = ! obs]vation ( l&m>ks4 ,z ! ,pilot & ,obs]v] approa* ! ,a]oplane ! =m] is cle>ly n 9 ! be/ ( temp]s4 8,x's rott5 luck10 he is say+1 8a blank %ame t ,i %\ld h to take ?is bless$ 'bus & jo9 ,x ,res]ve ,squadron1 /ation$ a hundr$ & fifty miles f any:]e2 & j z ,i h lick$ my ,flight into %ape4 ,n[ "s slack blight] w1 ,i suppose1 comm& x & get ! cr$it ( all my "w60 8,%ut up1 y gr\s]10 said ! ,obs]v]4 8,d y ?9k y're ! only "o ) tr\bles8 ,hav5't ,i be5 ?r\gh x too8 ,oh6 ,i "k all ab\t x6 ,y're f ! ,special ,res]ve & y\r ,c4,o4 doesn't l y\r /yle ( beauty1 & y won't lick 8 boots1 & y 7 a bit ( a te*nical knut 9 civil life1 b n[ y've jolly well got to "k less ?an ^? s5ior to y4 ,well6 ,x's a jolly good exp]i5ce = mo/ ( u4 ,p]haps conceit won't be at q su* a premium aft] ?is w>4 ,& :at's ! use ( gr\s+8 ,t nev] help$ anyone4 ,s buck up1 old *ap4 ,y\r day w come yet4 ,"h's our ma*9e1 & ,i mu/ say x looks a beauty60 ,&1 z ! ,pilot approa*es ! ,a]oplane1 8 face bright5s & he soon =gets 8 tr\bles z he critically inspects ! craft :i* is to transport him & ! ,obs]v] ov] ! hills & f> away4 ,turn+ to ! ,flight-,s]geant he inquires1 8,tank full ( petrol & oil80 8,yes1 sir10 he replies1 8& ev]y?+ else all correct4 ,propell]1 eng9e1 & body cov]s on bo>d1 sir2 tool kit *eck$ ov] & 9 ! lock]2 eng9e & ,a]oplane logbooks writt5 up1 sign$1 & "u y\r seat2 eng9e revs4 up to m>k1 & all ! control cables 9 p]fect condition & t5sion40 8,v good10 said ! ,pilot2 & !n turn+ to ! ,obs]v]1 8,be=e we />t y _h bett] h a look at ! c\rse ,i h mapp$ out4 8,a is :]e we /& & we h to rea* ,b1 a hundr$ & fifty miles due ,nor?4 ,i judge t1 at ! altitude we %all fly1 !re w be an ,ea/ w9d1 = al?\gh x is n q ,ea/ on ! gr\nd x is probably ab\t tw5ty degrees diff]5t al(t1 ! w9d usually mov+ r\nd clockways to ab\t t ext5t4 ,i ?9k t x is bl[+ at ! rate ( ab\t fifty miles an h\r1 & ,i !re=e take a l9e on ! map to ,c1 fifty miles due ,we/ ( ,a4 ,! ,a]oplane's spe$ is a hundr$ miles an h\r1 & s ,i take a l9e ( "o hundr$ miles f ,c to ,d4 ,our compass c\rse w !n be 9 ! direction ,a--,e1 :i* is always a l9e p>allel to ,c--,d4 ,t is1 to be exact1 x w be f\rte5 degrees (f ! ,c--,d c\rse1 z1 9 ?is "p ( ! globe1 !re is t mu* diff]5ce betwe5 ! ,nor? & ,s\? l9es on ! map & ! magnetic ,nor? to :i* ! compass ne$le po9ts4 ,if ! compass has an error1 z x may h ( a few degrees1 t1 too1 mu/ be tak5 into acc\nt1 & ! deviation or error curve on ! da%bo>d w indicate x4 8,! ,a]oplane w !n always be po9t+ 9 a direction p>allel to ,a--,e1 b1 ow+ to ! side w9d1 x w be actually travell+ ov] ! c\rse ,a--,b1 ?\gh 9 a r sideways attitude to t c\rse4 8,! di/ance we %all travel ov] ! ,a--,b c\rse 9 "o h\r is ,a--,d4 ,t is ne>ly eighty-sev5 miles1 s we ought to accompli% our j\rney ( a hundr$ & fifty miles 9 ab\t "o & ?ree-qu>t] h\rs4 8,i hope t's q cle> to y4 ,x's a v simple way ( calculat+ ! compass c\rse1 & ,i always d x l t40 8,yes1 t's pla9 en\gh4 ,y h draft$ :at eng9e]s call 'a p>allelogram ( =ces'2 b suppose y h miscalculat$ ! velocity ( ! w9d1 or t x %\ld *ange 9 velocity or direction80 8,well1 t ( c\rse w m or less alt] matt]s10 replies ! ,pilot4 8,b !re are any numb] ( good l&m>ks su* z lakes1 riv]s1 t[ns1 & railway l9es4 ,!y w help to keep u on ! "r c\rse1 & ! compass w1 at any rate1 prev5t u f go+ f> a/ray :5 betwe5 !m40 8,well1 we'd bett] be (f1 old *ap4 ,hop abo>d40 ,?is f ! ,obs]v] z he climbs into ! front seat f :i* he w comm& a good view ov] ! l[] plane2 & ! ,pilot takes 8 place 9 ! re> seat1 &1 aft] mak+ himself p]fectly com=table1 fix+ 8 safety belt1 & mov+ ! control lev]s to make sure t !y are work+ freely1 he gives ! signal to ! ,eng9e ,fitt] to turn ! propell] & s />t ! eng9e4 ,r\nd buzzes ! ,propell]1 & ! ,pilot1 giv+ ! (ficial signal1 ! ,a]oplane is releas$ & rolls swiftly ov] ! gr\nd 9 ! tee? ( ! gu/y w9d4 ,9 less ?an fifty y>ds x takes to ! air & beg9s to climb rapidly upw>ds1 b h[ diff]5t are ! conditions to ! calm morn+ ( ye/]day6 ,if ! air 7 visible x w\ld be se5 to be act+ 9 ! mo/ extraord9>y mann]2 crazily swirl+1 lift+ & dropp+1 gu/s vici\sly collid+--a mad phantasmagoria ( =ces6 ,wick$ly x seizes & %akes ! ,a]oplane2 !n tries to turn x ov] sideways2 !n in/antly *anges its m9d & 9 a second drops x into a hole a hundr$ feet deep1 & if x 7 n = 8 safety belt ! ,pilot might f9d 8 seat s9k+ away f b5ea? him4 ,gu/s /rike ! front ( ! craft l s _m slaps 9 ! face2 & o!rs1 ) ! motion ( m\nta9\s waves1 sometimes lift x hundr$s ( feet 9 a few seconds1 hop+ to see x plunge ov] ! summit 9 a dea?-dive--& s x goes on1 b ! ,pilot1 p]fectly at "o ) 8 m\nt & in/antly al]t to its slighte/ motion1 is skilfully & naturally mak+ p]haps fifty movem5ts a m9ute ( h& & feet2 ! =m] lightly grasp+ ! 8joy-/ick0 :i* controls ! ,elevator h+$ to ! tail1 & also ! ,ail]ons or little w+s h+$ to ! w+-tips2 & ! latt] mov+ ! ,rudd] control-b>4 ,a /ra9 on ! ,pilot8 ,n a bit ( x1 = ?is is 8 ,"w :i* he loves & excels 92 & giv5 a cool head1 al]t eye1 & a s5sitive t\* = ! controls1 :at sport c comp>e ) ^! ev]-*ang+ battles ( ! air8 ,! ,a]oplane has all ?is "t be5 climb+ 9 great wide circles1 & is n[ "s ?ree ?\s& feet above ! ,a]odrome :i* f su* height looks absurdly small4 ,! build+s bel[ n[ seem q squat2 ! hills appe> to h sunk away into ! gr\nd1 & ! :ole c\ntry bel[1 cut up into dim9utive fields1 has ! appe>ance ( hav+ be5 lately tidi$ & ?or\ghly spr+-clean$6 ,a doll's c\ntry x looks1 ) t9y horses & c[s ornam5t+ ! fields & little model motor-c>s & c>ts /uck on ! roads1 ! latt] /ret*+ away across ! c\ntry l ribbons accid5tally dropp$4 ,at ?ree ?\s& feet altitude ! ,pilot is satisfi$ t he is n[ suffici5tly high to secure1 9 ! ev5t ( eng9e failure1 a long en\gh glide to e>? to enable him to *oose & rea* a good l&+-place2 &1 be+ fur!rmore cont5t ) ! /eady runn+ ( ! eng9e1 he decides to climb no m b to foll[ ! c\rse he has mapp$ out4 ,consult+ ! compass1 he places ! ,a]oplane on ! ,a--,e c\rse &1 us+ ! ,elevator1 he gives 8 craft its m9imum angle ( incid5ce at :i* x w j ma9ta9 horizontal flight & secure its maximum spe$4 ,swiftly he spe$s away1 & few ?\ghts he has n[ = ! *ang+ panorama ( c\ntry1 cl\d1 & col\r4 ,ev] pres5t 9 8 m9d are ! ?ree great 'cross-c\ntry qu]ies4 8,am ,i on my "r c\rse8 ,c ,i see a good l&+-gr\nd )9 glid+ di/ance80 ,& 8,h[ is ! ,eng9e runn+80 ,ke5ly bo? he & ! ,obs]v] comp>e _! maps ) ! c\ntry bel[4 ,! roads1 khaki-col\r$ ribbons1 are easily se5 b are n ( mu* use1 = !re are s _m ( !m & !y all look alike f su* an altitude4 ,n[ :]e c t lake be :i* ! map %[s s pla9ly8 ,he feels t surely he %\ld see x by n[1 & has an uncom=table feel+ t he is fly+ too f> ,we/4 ,:at pilot is !re inde$ :o has n _m times exp]i5c$ su* unpleasant s5sation8 ,few ?+s 9 ! air c create great] anxiety4 ,wisely1 h[ev]1 he /icks to 8 compass c\rse1 & ! next m9ute he is rew>d$ by ! sight ( ! lake1 ?\gh inde$ he n[ sees t ! direction ( 8 travel w n take him ov] x1 z %\ld be ! case if he 7 fly+ ov] ! %orte/ r\te to 8 de/9ation4 ,he mu/ h slightly miscalculat$ ! velocity or direction ( ! side-w9d4 8,ab\t t5 degrees (f10 he mutt]s1 &1 us+ ! ,rudd]1 corrects 8 c\rse accord+ly4 ,n[ he feels happi] & t he is well on 8 way4 ,! gu/s1 too1 h ceas$ to tr\ble him z1 at ?is altitude1 !y are n ne>ly s bad z !y 7 ne> ! gr\nd ! brok5 surface ( :i* does mu* to produce !m2 & sometimes = miles he makes b a movem5t or two ( ! controls4 ,! cl\ds j above race by ) dizzy & uni=m spe$2 ! c\ntry bel[ sl[ly unrolls1 & ! /eady drone ( ! ,eng9e is almo/ hypnotic 9 effect4 8,sleep1 sleep1 sleep10 x insidi\sly sugge/s4 8,li/5 to me & wat* ! cl\ds2 !re's no?+ else to d4 ,dream1 dream1 dream ( spe$+ ?r\gh space = ev]1 & ev]1 & ev]2 & re/1 re/1 re/ to ! s\nd ( my rhy?mical hum4 ,dron+ on & on1 no?+ :atev] matt]s4 ,all ?+s n[ are m]g$ into spe$ ?r\gh space & a sleepy monoton\s d-d-r-r-o-o-n-n-e - - - - -40 ,b ! ,pilot pulls himself toge!r ) a />t & pe]s f> ahead 9 se>* ( ! next l&m>k4 ,?is "t x is a little c\ntry t[n1 r$-ro($ 8 map tells him1 & r\ghly ( cruci=m %ape2 &1 sure en\gh1 !re 9 ! "r direction are ! brok5 outl9es ( a few r$ ro(s peep+ out f betwe5 ! trees4 ,ano!r m9ute & he c see ?is little t[n1 a fairy t[n x appe>s1 ne/l+ d[n betwe5 ! hills ) its r$ ro(s & picturesque %ape1 a gl[+ & lovely contra/ ) ! d>k gre5 ( ! surr\nd+ moors4 ,s extraord9>ily clean & tidy x looks f su* a height1 & laid out 9 su* ord]ly fa%ion ) p]fectly def9$ squ>es1 p>ks1 av5ues1 & public build+s1 x inde$ appe>s h>dly real1 b r z if x has ?is v day mat]ializ$ f "s delightful *ildr5's book6 ,e city & t[n y mu/ "k has its di/9ct individuality to ! ,pilot's eye4 ,"s are n fairy places at all1 b great d>k ugly blots ^u ! fair c\ntryside1 & ) tall %afts bel*+ =? murky columns ( smoke to defile clean space4 ,o!rs1 melan*oly-look+ masses ( grey1 slate-ro($ h\ses1 are always sad & dispirit$2 nev] welcom+ ! glad sun%9e1 b ev] call+ = lead5 skies & a weep+ ,heav54 ,o!rs aga91 little coquettes ) village gre51 :ite pal+s ev]y:]e1 bright gravel roads1 & an irrepressible air ( brightness & gaiety4 ,!n !re are ! riv]s1 silv]y /reaks peacefully w9d+ f>1 f> away to ! di/ant horizon2 !y & ! lakes ! f9e/ l&m>ks ! ,pilot c h4 ,& ! =e/s4 ,h[ c ,i describe !m8 ,! trees _c be se5 sep>ately1 b m]ge altoge!r into enorm\s irregul> d>k gre5 masses sprawl+ ov] ! c\ntry1 & sometimes ) great unga9ly arms half encircl+ "s t[n or village2 & ! w9d pass+ ov] ! foliage at times gives ! =e/ an almo/ liv+ appe>ance1 z ( "s great dragon ( old5 times r\s+ itself f slumb] to dev\r ! peaceful villages :i* its arms encircle4 ,& ! ,pilot & ,obs]v] fly on & on1 see+ ^! ?+s & _m o!rs :i* baffle my poor skill to describe--?+s1 de> ,read]1 t y %all see1 & poets s+ (1 & great arti/s pa9t 9 ! days to come :5 ! ,design] has captur$ ,effici5cy4 ,!n1 & ! "t is ne>1 %all y see ?is beautiful _w z y h nev] se5 x be=e1 ! g>d5 x is1 ! peace x brea!s1 & ! wond] ( x4 ,! ,pilot1 fly+ on1 is n[ anxi\sly look+ = ! railway l9e :i* midway on 8 j\rney %\ld po9t ! c\rse4 ,ah6 ,!re x is at la/1 b sudd5ly 7& ! map at fault7 x plunges into ! e>?6 ,well ! writ] rememb]s :5 t happ5$ to him on a long 'cross-c\ntry flight 9 ! e>ly days ( aviation4 ,anxi\sly he wond]$ 8,are tunnels always /raight80 & ) :at relief1 keep+ on a /raight c\rse1 he pick$ up ! l9e aga9 "s ?ree miles f>!r on6 ,n[ at la/ ! ,pilot sees ! sea1 j a /reak on ! nor?-ea/]n horizon1 & he kn[s t 8 flight is two-?irds ov]4 ,inde$1 he %\ld h se5 x be=e1 b ! air is none too cle>1 & he is n yet able to disc]n ! riv] :i* soon %\ld cross 8 pa?4 ,z he swiftly spe$s on ! air becomes d5s] & d5s] ) :at he fe>s mu/ be ! beg9n+ ( a sea-fog1 p]haps drift+ inl& along ! c\rse ( ! riv]4 ,n[ does he feel real anxiety1 = x is ! ,,duty ( a ,pilot to fe> fog1 8 deadlie/ enemy4 ,fog n only hides ! l&m>ks by :i* he keeps 8 c\rse1 b makes ! control ( ! ,a]oplane a matt] ( ! greate/ difficulty4 ,he may n realize x1 b1 9 keep+ 8 ma*9e on an ev5 keel1 he is unconsci\sly balanc+ x aga9/ ! horizon1 & ) ! horizon gone he is lo/ inde$4 ,n only t1 b x also prev5ts him f *oos+ 8 l&+-place1 & ! *ances are t1 l&+ 9 a fog1 he w sma% into a tree1 h$ge1 or build+1 ) disa/r\s results4 ,! be/ & bolde/ pilot 'w>es a fog1 & s ?is "o1 f9d+ ! conditions becom+ worse & yet worse1 & be+ =c$ to desc5d l[] & l[] 9 ord] to keep ! e>? )9 view1 wisely decides to *oose a l&+-place :ile !re is yet "t to d s4 ,?rottl+ d[n ! p[] ( ! eng9e he spirals d[nw>ds1 ke5ly obs]v+ ! c\ntry bel[4 ,!re are pl5ty ( gre5 fields to lure him1 & 8 great object is to avoid "o 9 :i* ! grass is long1 = t w\ld br+ 8 ma*9e to a /op s sudd5ly z to turn x ov]2 or "o ( r\gh surface likely to break ! "u-c>riage4 ,n[ is p]fect eyesight & a cool head indisp5sable4 ,he sees & decides ^u a field &1 kn[+ 8 job1 he /icks to t field ) no *ange ( m9d to confuse him4 ,x is none too l>ge1 & glid+ j ov] ! trees & head on to ! w9d he skilfully 8/alls0 8 ma*9e2 t is1 ! spe$ hav+ decreas$ suffici5tly to avoid su* a manoeuvre result+ 9 asc5t1 he1 by means ( ! ,elevator1 gives ! ,a]oplane z l>ge an angle ( incid5ce z possible1 & ! und]sides ( ! planes meet+ ! air at su* a l>ge angle act z an air-brake1 & ! ,a]oplane1 skimm+ ov] ! gr\nd1 less5s its spe$ & f9ally /ops j at ! f>!r end ( ! field4 ,!n1 aft] driv+ ! ,a]oplane up to & "u ! lee ( ! h$ge1 he /ops ! eng9e1 & quickly la%+ ! joy-/ick fa/ 9 ord] to prev5t ! w9d f bl[+ ! controll+ surfaces ab\t & possibly damag+ !m1 he hurri$ly alights4 ,n[ runn+ to ! tail he lifts x up on to 8 %\ld]1 = ! w9d has become r\gh inde$ & !re is dang] ( ! ,a]oplane becom+ unmanageable4 ,by ?is action he decreases ! angle at :i* ! planes are incl9$ to ! w9d & s m9imizes ! latt]'s effect ^u !m4 ,!n to ! ,obs]v]1 8,hurry up1 old fell[1 & try to f9d "s rope1 wire1 or any?+ ) :i* to picket ! ma*9e4 ,! w9d is ris+ & ,i %an't be able to hold ! 'bus /eady = long4 ,don't =get ! wire-cutt]s4 ,!y're 9 ! tool kit40 ,& ! ,obs]v] ru%es (f 9 frantic ha/e1 be=e long triumphantly return+ ) a long l5g? ( wire f a neighb\r+ f5ce4 ,block+ up ! tail ) "s debris at h&1 !y soon succe$1 ) ! aid ( ! wire1 9 /\tly picket+ ! ,a]oplane to ! roots ( ! high h$ge 9 front ( x2 done ) mu* c>e1 too1 s t ! wire %all n fray ! fabric or set up dang]\s b5d+-/resses 9 ! woodwork4 ,_! "w is n done yet1 = ! ,obs]v] rem>k+1 8,i don't l ! look ( ?is ?ick wea!r & r fe> a heavy ra9-/orm10 ! ,pilot replies1 8,well1 x's a fe>ful bore1 b ! fir/ rule ( our game is nev] to take an unnecess>y risk1 s out ) ! eng9e & body cov]s40 ,work+ ) a w !y soon h ! eng9e & ! op5 "p ( ! body :i* conta9s ! seats1 controls1 & in/rum5ts snugly h\s$ ) _! wat]pro( cov]s1 & ! ,a]oplane is ready to wea!r ! possible /orm4 ,says ! ,obs]v]1 8,i'm rem>kably pecki%1 & me?9ks ,i spy ! t[]s ( "o ( ,engl&'s /ately homes %[+ !mselves j beyond t wood1 less ?an a qu>t] ( a mile away4 ,:at ho6 = a raid4 ,:at d y say80 8,all "r1 y cut along & ,i'll /op "h1 = ! ,a]oplane mu/ n be left alone4 ,get back z quickly z possible40 ,& ! ,obs]v] trots (f1 leav+ ! ,pilot fill+ 8 pipe & anxi\sly scrut9iz+ ! wea!r conditions4 ,v ?ick x is n[1 b ! day is yet "y1 & he has hopes ( ! fog lift+ suffici5tly to enable ! flight to be resum$4 ,a little impati5tly he awaits ! return ( 8 comrade1 b ) nev] a d\bt ( ! result1 = ! hospitality ( ! c\ntry h\se is prov]bial among pilots6 ,:at old h& among !m is !re :o _c in/ance _m a =c$ l&+ made pleasant by su* hospitality8 ,nev] too late or too e>ly to help ) food1 petrol1 oil1 tools1 & assi/ants4 ,_m a grateful ?\ght has ! writ] = su* k9d help giv5 9 ! days be=e ! w> 7h[ long ago !y seem671 :5 a]oplanes 7 /ill m imp]fect ?an !y are n[1 & involunt>y desc5ts (t5 a "p ( 'cross-c\ntry fly+4 ,ah6 ^? e>ly days6 ,h[ fre% & inspir+ !y 76 ,z "o />t$ (f on "o's fir/ 'cross-c\ntry flight1 on a ma*9e ! fir/ ( its design1 & ) ev]y?+ yet to le>n1 & ! wond]s ( ! air yet to explore2 !n ! joy ( accompli%m5t1 ! dreams ( ,effici5cy1 ! h>d "w & long h\rs bett] ?an leisure2 & :at a field ( endeav\r--! realms ( space to conqu]6 ,& ! battle /ill goes on ) ev]-increas+ success4 ,:o is bold en\gh to say :at its limits %all be8 ,s rum9ates ?is ,pilot-,design]1 z he puffs at 8 pipe1 until 8 rev]ie is abruptly di/urb$ by ! return ( ! ,obs]v]4 8,wake up1 y ,,airman10 ! latt] %\ts4 8,"h's ! v ?+ ! doctor ord]$6 ,a basket ( fir/-class grub & some?+ to keep ! fog out1 too40 8,well1 t's spl5did1 b don't call me newspap] names or y'll spoil my appetite60 ,!n1 ) hung] su* z only fly+ c produce1 !y appreciatively discuss _! lun*1 & ) _m a grateful ?\ght = ! donors--& !y talk %op4 ,!y c't help x1 & ev5 golf is a poor second to flight talk4 ,says ! ,pilot1 :o mu/ h 8 grievance1 8,j obs]ve :]e ,i manag$ to /op ! ma*9e4 ,n tw5ty feet f ?is h$ge6 ,a little m & we %\ld h be5 ?r\gh x & into ,k+dom ,come6 ,i /all$ z well z "o c\ld1 b ! tail t\*$ ! gr\nd & s ,i c\ld n give ! ,a]oplane any l>g] angle ( incid5ce4 ,c\ld ,i h giv5 x a l>g] angle1 !n ! planes w\ld h become a mu* m effective air-brake1 & we %\ld h come to re/ 9 a mu* %ort] di/ance4 ,x's all ! fault ( ! tail4 ,!re's h>dly a type ( ,a]oplane 9 exi/5ce 9 :i* ! tail c\ld n be rais$ sev]al feet1 & t w\ld make all ! diff]5ce4 ,high tails mean a l>ge angle ( incid5ce :5 ! ma*9e t\*es gr\nd &1 ) en\gh angle1 ,i'll gu>antee to safely l& ! fa/e/ ma*9e 9 a five-acre field4 ,y c1 ,i am sure1 imag9e :at a diff]5ce t w\ld make :]e =c$ l&+s are conc]n$60 ,!n rapidly sket*+ 9 8 notebook1 he %[s ! ,obs]v] ! foll[+ illu/ration3 8,t's v pretty10 said ! ,obs]v]1 8b h[ ab\t ,me*anical ,difficulties1 & ,effici5cy 9 respect ( ,flight8 ,&1 anyway1 :y hasn't su* an obvi\s ?+ be5 done already80 8,z reg>ds ! fir/ "p ( y\r "q ,i assure y t !re's no?+ 9 x1 & ,i'll prove x to y z foll[s----0 8,oh6 ,t's all "r1 old *ap4 ,i'll take y\r ^w = x10 hurri$ly replies ! ,obs]v]1 ^: s\l isn't tun$ to a te*nical key4 8,z reg>ds ! latt] "p ( y\r inquiry10 w5t on ! ,pilot1 a little nettl$ at hav+ su* a poor li/5]1 8x's v simple4 ,a]oplanes h 'j gr[$' l ,topsy1 & !y consequ5tly conta9 ?is & _m ano!r relic ( e>ly day design :5 ,a]oplanes 7 m or less ?r[n toge!r & any?+ 0 good en\gh t c\ld get (f ! gr\nd40 8,by ,jove10 int]rupts ! ,obs]v]1 8,i d believe ! fog is lift+4 ,hadn't we bett] get ! eng9e & body cov]s (f1 j 9 case x's really s80 8,i believe y're "r4 ,i am sure ^? hills ov] !re c\ld n be se5 a few m9utes ago1 & look--!re's sun%9e ov] !re4 ,we'd bett] hurry up40 ,t5 m9utes' h>d "w & ! cov]s are (f1 neatly fold$ & /[$ abo>d2 ! picket+ wires are ca/ adrift1 & ! ,pilot is once m 9 8 seat4 ,! ,a]oplane has be5 turn$ to face ! o!r end ( ! field1 &1 ! ,obs]v] sw++ r\nd ! propell]1 ! eng9e is awake aga9 & sl[ly tick+ ov]4 ,quickly ! ,obs]v] climbs into 8 seat 9 front ( ! ,pilot1 &1 ! latt] slightly op5+ ! ?rottle1 ! ,a]oplane leisurely rolls ov] ! gr\nd t[>ds ! o!r end ( ! field1 f :i* ! asc5t w be made4 ,arriv+ !re ! ,pilot turns ! ,a]oplane 9 ord] to face ! w9d & ?us secure a quick 8get-(f40 ,!n he op5s ! ?rottle fully & ! mighty voice ( ! ,eng9e ro>s out 8,n[ see me cle> t h$ge60 & ! ,a]oplane races =w>d at its m9imum angle ( incid5ce4 ,tail up1 & ) ev]-increas+ spe$1 x ru%es t[>ds ! h$ge "u ! lee ( :i* x has lately be5 at re/2 & !n1 j z ! ,obs]v] involunt>ily pulls back an imag9>y 8joy-/ick10 ! ,pilot moves ! real "o & places ! ma*9e at its be/ climb+ angle4 ,l a liv+ ?+ x responds1 & in/antly leaves ! gr\nd1 cle>+ ! h$ge l a--well1 l an ,a]oplane ) an excell5t m>g9 ( lift4 ,upw>ds x climbs ) ev5 & p[]ful lift1 & ! famili> sc5es bel[ aga9 gladd5 ! eyes ( ! ,pilot4 ,small] & m & m squat gr[ ! h\ses & hills2 m & m doll-l appe> ! fields :i* are cle>ly outl9$ by ! h$ges2 & soon ! c\ntry bel[ is easily id5tifi$ ) ! map4 ,n[ !y c see ! riv] be=e !m & a bay ( ! sea :i* mu/ be cross$ or skirt$4 ,! fog /ill l+]s along ! c\rse ( ! riv] & betwe5 ! hills1 b is fa/ roll+ away 9 grey1 gho/-l masses4 ,out to sea x obscures ! horizon1 mak+ x difficult to be sure :]e wat] ends & fog beg9s1 & creat+ a /range1 r weird effect by :i* %ips at a c]ta9 di/ance appe> to be float+ 9 space4 ,n[ ! ,a]oplane is almo/ ov] ! riv]1 & ! next in/ant x sudd5ly drops into a 8hole 9 ! air40 ,) great sudd5ness x happ5s1 & = "s two hundr$ feet x drops nose-d[n & tilt$ ov] sideways2 b ! ,pilot is prep>$ & has put 8 craft on an ev5 keel 9 less "t ?an x takes to tell y ab\t x2 = well he kn[s t he mu/ expect su* conditions :5 pass+ ov] a %ore or1 inde$1 any well-def9$ *ange 9 ! composition ( ! e>?'s surface4 ,especially is ?is s on a hot & sunny day1 = !n ! w>m surface ( ! e>? creates columns ( asc5d+ air1 ! spe$ ( ! asc5t dep5d+ ^u ! composition ( ! surface4 ,s&y soil1 = in/ance1 su* z bord]s ?is riv] produces a quickly asc5d+ column ( air1 :]eas wat] & =e/s h n su* a m>k$ effect4 ,?us1 :5 our ,a]oplane pass$ ov] ! %ore ( ! riv]1 x sudd5ly lo/ ! lift due to ! asc5d+ air produc$ by ! w>m s&y soil1 & x consequ5tly dropp$ j z if x _h fall5 into a hole4 ,n[ ! ,a]oplane is ov] ! bay &1 ! sea be+ calm1 ! ,pilot looks d[n1 d[n ?r\gh ! wat]1 & cle>ly sees ! bottom1 hundr$s ( feet bel[ ! surface4 ,d[n ?r\gh ! reflection ( ! blue sky & cl\ds1 & "o might ?9k t is all1 b x isn't4 ,only ^? :o fly "k ! beauties ( ! sea z view$ f above2 its dappl$ pe>ly t9ts2 its s(t d>k blue %ad[s2 ! beautiful contra/s ( unusual %ades ( col\r :i* are always diff]+ & %ift+ ) ! *ang+ sun%9e & ! ev] mov+ position ( ! a]ial obs]v]4 ,ah6 = "s bett] p5 ?an m9e to describe ^! ?+s6 ,"o ) gl[+ words & a magic rhy?m to express ! wond]s ( ! air & ! beauty ( ! g>d5 b5ea?--! imm5sity ( ! sea--! s5se ( space & ( "o's littl5ess !re--! realization ( ! ,p[] mov+ ! multitudes bel[--! exaltation ( _s altitude produces--! joy ( spe$4 ,a new _w ( s5sation6 ,n[ ! bay is almo/ cross$ & ! ,a]odrome at ,b c be di/+ui%$4 ,on ! ,a]odrome is a little cr[d wait+ & wat*+ = ! arrival ( ! ,a]oplane1 = x is ( a new & improv$ type & its fir/ 'cross-c\ntry p]=mance is ( ke5 int]e/ to ^! m52 m5 :o really "k some?+ ab\t flight4 ,!re is ! ,squadron ,comm&] :o has done "s real fly+ 9 8 "t2 sev]al well-season$ ,flight-,comm&]s2 a doz5 or m ,flight-,lieut5ants2 a kn[l$geable ,flight-,s]geant2 a numb] ( ,air ,me*anics1 &1 a little on "o side & almo/ unnotic$1 ! ,design]4 8,i hope !y are all "r10 said someone1 8& t !y hav5't _h difficulties ) ! fog4 ,x roll$ up v quickly1 y "k40 8,nev] fe>10 rem>k$ a ,flight-,comm&]4 8,i "k ! ,pilot well & he's a good 'un2 f> too good to c>ry on into a fog40 8,!y say ! ma*9e is really some?+ out ( ! ord9>y10 said ano!r1 8& t1 = once1 ! ,design] has be5 all[$ full play2 t he hasn't be5 =c$ to unduly /&>dize ribs1 sp>s1 /ruts1 etc41 & has m or less _h 8 own way4 ,i wond] :o he is4 ,x seems /range we he> s little ( him40 8,ah6 my boy4 ,y d a bit m fly+ & y'll discov] t ?+s are n always z !y appe> f a di/ance60 8,!re %e is1 sir60 cries ! ,flight-,s]geant4 8,j a speck ov] ! silv]y corn] ( t cl\d40 ,a t9y speck x looks1 "s six miles di/ant & ?ree ?\s& feet high2 b1 rac+ along1 x rapidly appe>s l>g] & soon its outl9es c be trac$ & ! sunlight be se5 play+ ^u ! :irl+ propell]4 ,n[ ! di/ant drone ( ! eng9e c be he>d1 b n = long1 = sudd5ly x ceases &1 ! nose ( ! ,a]oplane s9k+1 ! craft comm5ces glid+ d[nw>ds4 8,surely too f> away10 says a subalt]n4 8,x w be a wond]ful ma*9e if1 f t di/ance & height1 x c glide into ! ,a]odrome40 ,& m ?an "o express ! op9ion t x _c be done2 b ! ,design] smiles to himself1 yet ) a little anxiety1 = 8 reputation is at /ake1 & ,effici5cy1 ! ma9 rew>d he desires1 is p]haps1 or p]haps n1 at la/ )9 8 grasp6 ,swiftly ! ma*9e glides d[nw>ds t[>ds !m1 & x c n[ be se5 h[ surpris+ly little x is affect$ by ! r\gh wea!r & gu/s2 s mu* s t a little *orus ( approval is he>d4 8,jolly good glid+ angle10 says someone2 & ano!r1 8,beautifully quick controls1 :at80 & f yet ano!r1 8,by ,jove6 ,! ,pilot mu/ be sure ( ! ma*9e4 ,look1 he's /opp$ ! eng9e entirely40 ,!n ! ,a]oplane ) noiseless eng9e glides ov] ! b\nd>y ( ! ,a]odrome1 &1 ) j a s(t s\gh+ s\nd f ! air x cleaves1 l&s g5tly n fifty y>ds f ! onlook]s4 8,glad to see y10 says ! ,squadron ,comm&] to ! ,pilot4 8,h[ d y l ! ma*9e80 ,& ! ,pilot replies3 8,i nev] want a bett] "o1 sir4 ,x almo/ flies itself60 ,& ! ,design] turns 8 face homew>ds & t[>ds 8 belov$ draw+-(fice2 well satisfi$1 b /ill dream+ dreams ( ! future &444 look+ f> ahead :om %\ld he see b ,effici5cy at la/ com+ t[>ds him6 ,& to him %e is all ?+s4 ,9 h] hair is ! morn+ sun%9e2 h] eyes hold ! blue ( ! sky1 & on h] *eeks is ! pe>ly t9t ( ! cl\ds z se5 f above4 ,! passion ( spe$1 ! lure ( space1 ! s5se ( p[]1 & ! wond] ( ! future444 all ^! ?+s %e holds = him4 8,ah60 he cries4 8,y'll nev] leave me n[1 :5 at la/ !re is no "o betwe5 u80 ,& ,effici5cy1 smil+ & blu%+1 b practical z ev]1 says3 8,& y w nev] ?r[ ^? ,compromises 9 my face80 8,my de>1 ,i love y = !m6 ,hav5't !y be5 my life ev] s9ce ,i began /riv+ = y t5 long ye>s ago80 ,& s !y walk$ (f v happily1 arm-9-arm toge!r2 & if ?is hasn't bor$ y & y'd l "s m ( ! same sort ( ?+1 ,i'd j love to tell y "s day ( ! wond]ful ?+s !y accompli% toge!r1 & ( :at !y dream ! future holds 9 /ore4 ,& t's ! end ( ! ,prologue4 ,,*apt] ,i4 ,,flight ,air has weight 7ab\t #ac cubic feet #a lb471 in]tia1 & mom5tum4 ,x !re=e obeys ,newton's laws#ad & resi/s movem5t4 ,x is t resi/ance or reaction :i* makes flight possible4 ,flight is secur$ by driv+ ?r\gh ! air a surface#ae incl9$ upw>ds & t[>ds ! direction ( motion4 ,s ,side view ( surface4 ,m ,direction ( motion4 ,,*ord4--,! ,*ord is1 = practical purposes1 tak5 to be a /raight l9e f ! lead+ edge ( ! surface to its trail+ edge4 ,n ,a l9e ?r\gh ! surface />t+ f its trail+ edge4 ,! position ( ?is l9e1 :i* ,i call ! ,neutral ,lift ,l9e1 is f\nd by means ( w9d-tunnel rese>*1 & x v>ies ) diff]5ces 9 ! camb] 7curvature7 ( surfaces4 ,9 ord] to secure flight1 ! incl9ation ( ! surface mu/ be su* t ! neutral lift l9e makes an angle ) & ,,above ! l9e ( motion4 ,if x is co9cid5t ) ,m1 !re is no lift4 ,if x makes an angle ) ,m & ,,bel[ x1 !n !re is a pressure t5d+ to =ce ! surface d[n4 ,i ,angle ( ,incid5ce4 ,?is angle is g5]ally def9$ z ! angle ! *ord makes ) ! direction ( motion1 b t is a bad def9ition1 z x leads to misconception4 ,! angle ( incid5ce is be/ describ$ z ! angle ! neutral lift l9e makes ) ! direction ( motion relative to ! air4 ,y w1 h[ev]1 f9d t 9 ne>ly all rigg+ specifications ! angle ( incid5ce is tak5 to mean ! angle ! *ord makes ) a l9e p>allel to ! propell] ?ru/4 ,?is is necess>y f ! po9t ( view ( ! practical me*anic :o has to rig ! a]oplane1 = he c\ld n f9d ! neutral lift l9e1 :]eas he c easily f9d ! *ord4 ,aga91 he w\ld c]ta9ly be 9 d\bt z to 8! direction ( motion relative to ! air10 :]eas he c easily f9d a l9e p>allel to ! propell] ?ru/4 ,x is a pity1 h[ev]1 t ^! practical consid]ations h result$ 9 a bad def9ition ( ! angle ( incid5ce becom+ preval5t1 a consequ5ce ( :i* has be5 ! widespread fallacy t flight may be secur$ ) a negative incl9ation ( ! surface4 ,flight may conceivably be secur$ ) a negative angle ( *ord1 b nev] ) a negative incl9ation ( ! surface4 ,all ?is is only applicable to camb]$ surfaces4 ,9 ! case ( flat surfaces ! neutral lift l9e co9cides ) ! *ord & ! def9ition ,i h criticis$ adv]sely is !n applicable4 ,flat lift+ surfaces are1 h[ev]1 nev] us$4 ,! surface acts ^u ! air 9 ! foll[+ mann]3 ,z ! bottom ( ! surface meets ! air1 x compresses x & accel]ates x ,,d[nw>ds4 ,z a result ( ?is def9ite action !re is1 ( c\rse1 an equal & opposite reaction ,,upw>ds4 ,! top surface1 9 mov+ =w>d1 t5ds to leave ! air beh9d x1 ?us creat+ a semi-vacuum or r>efi$ area ov] ! top ( ! surface4 ,consequ5tly ! pressure ( air on ! top ( ! surface is decreas$1 ?us assi/+ ! reaction bel[ to lift ! surface ,,upw>ds4 ,! reaction increases approximately z ! squ>e ( ! velocity4 ,x is ! result ( 7#a7 ! mass ( air engag$1 & 7#b7 ! velocity & consequ5t =ce ) :i* ! surface engages ! air4 ,if ! reaction 0 produc$ by only "o ( ^? factors x w\ld increase 9 direct proportion to ! velocity1 b1 s9ce x is ! product ( bo? factors1 x increases z ,v7#b,s74 ,approximately ?ree-fif?s ( ! reaction is due to ! decrease ( d5sity 7& consequ5t decrease ( d[nw>d pressure7 on ! top ( ! surface2 & only "s two-fif?s is due to ! upw>d reaction secur$ by ! action ( ! bottom surface ^u ! air4 ,a practical po9t 9 respect ( ?is is t1 9 ! ev5t ( ! fabric cov]+ ! surface gett+ into bad condition1 x is m likely to /rip (f ! top ?an (f ! bottom4 ,! direction ( ! reaction is approximately at "r-angles to ! *ord ( ! surface1 z illu/rat$ above2 & x is1 9 consid]+ flight1 conv5i5t to divide x into two compon5t p>ts or values1 ?us3 #a4 ,! v]tical compon5t ( ! reaction1 i4e41 ,lift1 :i* is oppos$ to ,gravity1 i4e41 ! weight ( ! a]oplane4 #b4 ,! horizontal compon5t1 i4e41 ,drift 7sometimes call$ ,resi/ance71 to :i* is oppos$ ! ?ru/ ( ! propell]4 ,! direction ( ! reaction is1 ( c\rse1 ! resultant ( ! =ces ,lift & ,drift4 ,! ,lift is ! useful "p ( ! reaction1 = x lifts ! weight ( ! a]oplane4 ,! ,drift is ! villa9 ( ! piece1 & mu/ be ov]come by ! ,?ru/ 9 ord] to secure ! necess>y velocity to produce ! requisite ,lift = flight4 ,,drift4--,! drift ( ! :ole a]oplane 7we h consid]$ only ! lift+ surface h]et(ore7 may be conv5i5tly divid$ into ?ree p>ts1 z foll[s3 ,active ,drift1 :i* is ! drift produc$ by ! lift+ surfaces4 ,passive ,drift1 :i* is ! drift produc$ by all ! re/ ( ! a]oplane--! /ruts1 wires1 fuselage1 "u-c>riage1 etc41 all ( :i* is kn[n z 8detrim5tal surface40 ,sk9 ,friction1 :i* is ! drift produc$ by ! friction ( ! air ) r\ghnesses ( surface4 ,! latt] is practically negligible hav+ reg>d to ! smoo? surface ( ! mod]n a]oplane1 & its comp>atively sl[ velocity comp>$ )1 = in/ance1 ! velocity ( a propell] blade4 ,,lift-,,drift ,,ratio4--,! proportion ( lift to drift is kn[n z ! lift-drift ratio1 & is ( p>am\nt importance1 = x expresses ! effici5cy ( ! a]oplane 7z di/9ct f eng9e & propell]74 ,a k ( ! factors gov]n+ ! lift-drift ratio is1 z w be se5 lat]1 an absolute necessity to anyone responsible = ! rigg+ ( an a]oplane1 & ! ma9t5ance ( x 9 an effici5t & safe condition4 ,^? factors are z foll[s3 #a4 ,velocity4--,! great] ! velocity ! great] ! proportion ( drift to lift1 & consequ5tly ! less ! effici5cy4 ,consid]+ ! lift+ surfaces alone1 bo? ! lift & ! 7active7 drift1 be+ compon5t p>ts ( ! reaction1 increase z ! squ>e ( ! velocity1 & ! effici5cy rema9s ! same at all spe$s4 ,b1 consid]+ ! :ole a]oplane1 we mu/ rememb] ! passive drift4 ,x also increases z ! squ>e ( ! velocity 7) no att5dant lift71 &1 add+ itself to ! active drift1 results 9 increas+ ! proportion ( total drift 7active passive7 to lift4 ,b = ! increase 9 passive drift ! effici5cy ( ! a]oplane w\ld n fall ) increas+ velocity1 & x w\ld be possible1 by d\bl+ ! ?ru/1 to approximately d\ble ! spe$ or lift--a happy /ate ( affairs :i* c nev] be1 b :i* we may1 9 a measure1 approa* by do+ ev]y?+ possible to dim9i% ! passive drift4 ,e ef=t is !n made to decrease x by 8/ream-l9+10 i4e41 by giv+ all 8detrim5tal0 p>ts ( ! a]oplane a =m by :i* !y w pass ?r\gh ! air ) ! lea/ possible drift4 ,ev5 ! wires brac+ ! a]oplane toge!r are1 9 _m cases1 /ream-l9$1 & ) a m>k$ly good effect ^u ! lift-drift ratio4 ,9 ! case ( a c]ta9 well-kn[n type ( a]oplane ! replac+ ( ! ord9>y wires by /ream-l9$ wires add$ ov] five miles an h\r to ! flight spe$4 ,head-resi/ance is a t]m (t5 appli$ to passive drift1 b x is apt to convey a wrong impression1 z ! drift is n ne>ly s mu* ! result ( ! head or =w>d "p ( /ruts1 wires1 etc41 z x is ( ! r>efi$ area beh9d4 ,above is illu/rat$ ! fl[ ( air r\nd two objects mov+ 9 ! direction ( ! arr[ ,m4 ,9 ! case ( ,a1 y w note t ! r>efi$ area ,,dd is ( v consid]able ext5t2 :]eas 9 ! case ( ,b1 ! air fl[s r\nd x 9 su* a way z to meet v closely to ! re> ( ! object1 ?us ,,decreas+ ,,dd4 ,! great] ! r>efi$ area ,,dd4 !n1 ! less ! d5sity1 &1 consequ5tly1 ! less ! pressure ( air ^u ! re> ( ! object4 ,! less su* pressure1 !n1 ! bett] is head-resi/ance ,d able to get its "w 91 & ! m ?ru/ w be requir$ to ov]come x4 ,! 8f95ess0 ( ! /ream-l9e %ape1 i4e41 ! proportion ( l5g? to wid?1 is det]m9$ by ! velocity--! great] ! velocity1 ! great] ! f95ess4 ,! be/ degree ( f95ess = any giv5 velocity is f\nd by means ( w9d-tunnel rese>*4 ,! practical application ( all ?is is1 f a rigg+ po9t ( view1 ! importance ( adju/+ all /ream-l9e p>ts to be dead-on 9 ! l9e ( flight1 b m ( t lat] on4 #b4 ,angle ( ,incid5ce4--,! mo/ effici5t angle ( incid5ce v>ies ) ! ?ru/ at ! disposal ( ! design]1 ! weight to be c>ri$1 & ! climb-velocity ratio desir$4 ,! be/ angles ( incid5ce = ^! v>y+ factors are f\nd by means ( w9d-tunnel rese>* & practical trial & error4 ,g5]ally speak+1 ! great] ! velocity ! small] %\ld be ! angle ( incid5ce1 9 ord] to pres]ve a clean1 /ream-l9e %ape ( r>efi$ area & fre$om f eddies4 ,%\ld ! angle be too great = ! velocity1 !n ! r>efi$ area becomes ( irregul> %ape ) att5dant turbul5t eddies4 ,su* eddies possess no lift value1 & s9ce x has tak5 p[] to produce !m1 !y repres5t drift & adv]sely affect ! lift-drift ratio4 ,f a rigg+ po9t ( view1 "o mu/ presume t e /&>d a]oplane has its lift+ surface set at ! mo/ effici5t angle1 & ! practical application ( all ?is is 9 tak+ ! greate/ possible c>e to rig ! surface at ! correct angle & to ma9ta9 x at su* angle4 ,any deviation w adv]sely affect ! lift-drift ratio1 i4e41 ! effici5cy4 #c4 ,camb]4--7,ref] to ! second illu/ration 9 ?is *apt]47 ,! lift+ surfaces are camb]$1 i4e41 curv$1 9 ord] to decrease ! horizontal compon5t ( ! reaction1 i4e41 ! drift4 ,! bottom camb]3 ,if ! bottom ( ! surface 0 flat1 e p>ticle ( air meet+ x w\ld d s ) a %ock1 & su* %ock w\ld produce a v consid]able horizontal reaction or drift4 ,by curv+ x su* %ock is dim9i%$1 & ! curve %\ld be su* z to produce a uni=m 7n necess>ily con/ant7 accel]ation & compression ( ! air f ! lead+ edge to ! trail+ edge4 ,any unev5ness 9 ! accel]ation & compression ( ! air produces drift4 ,! top camb]3 ,if ?is 0 flat x w\ld produce a r>efi$ area ( irregul> %ape4 ,i h already expla9$ ! bad effect ?is has ^u ! lift-drift ratio4 ,! top surface is !n curv$ to produce a r>efi$ area ! %ape ( :i* %all be z /ream-l9e & free f att5dant eddies z possible4 ,! camb] v>ies ) ! angle ( incid5ce1 ! velocity1 & ! ?ickness ( ! surface4 ,g5]ally speak+1 ! great] ! velocity1 ! less ! camb] & angle ( incid5ce4 ,) inf9ite velocity ! surface w\ld be set at no angle ( incid5ce 7! neutral lift l9e co9cid5t ) ! direction ( motion relative to ! air71 & w\ld be1 top & bottom1 ( pure /reaml9e =m--i4e41 ( inf9ite f95ess4 ,?is is1 ( c\rse1 c>ry+ !ory to absurdity z ! surface w\ld !n cease to exi/4 ,! be/ camb]s = v>y+ velocities1 angles ( incid5ce1 & ?icknesses ( surface1 are f\nd by means ( w9d-tunnel rese>*4 ,! practical application ( all ?is is 9 tak+ ! greate/ c>e to prev5t ! surface f becom+ di/ort$ & ?us spoil+ ! camb] & consequ5tly ! lift-drift ratio4 #d4 ,aspect ,ratio4--,?is is ! proportion ( span to *ord4 ,?us1 if ! span is1 = in/ance1 #ej feet & ! *ord #e feet1 ! surface w\ld be said to h an aspect ratio ( #aj to #a4 ,= ,a ,,giv5 ,,velocity & ,a ,,giv5 ,,area ( surface1 ! great] ! aspect ratio1 ! great] ! reaction4 ,x is obvi\s1 ,i ?9k1 t ! great] ! span1 ! great] ! mass ( air engag$1 &1 z already expla9$1 ! reaction is p>tly ! result ( ! mass ( air engag$4 ,n only t1 b1 ,,provid$ ! *ord is n decreas$ to an ext5t mak+ x impossible to secure ! be/ camb] ow+ to ! ?ickness ( ! surface1 ! great] ! aspect ratio1 ! bett] ! lift-drift ratio4 ,! reason ( ?is is r obscure4 ,x is sometimes advanc$ t x is ow+ to ! 8spill0 ( air f "u ! w+-tips4 ,) a high aspect ratio ! *ord is less ?an w\ld o!rwise be ! case4 ,less *ord results 9 small] w+-tips & consequ5tly less 8spill40 ,?is1 h[ev]1 appe>s to be a r inadequate reason = ! high aspect ratio produc+ ! high lift-drift ratio4 ,o!r reasons are also advanc$1 b !y are ( su* a cont5ti\s nature ,i d n ?9k x well to g into !m "h4 ,!y are ( int]e/ to design]s1 b ?is is writt5 = ! practical pilot & rigg]4 #e4 ,/agg]4--,?is is ! advancem5t ( ! top surface relative to ! bottom surface1 & is n1 ( c\rse1 applicable to a s+le surface1 i4e41 a monoplane4 ,9 ! case ( a biplane hav+ no /agg]1 !re w be 8int]f]5ce0 & consequ5t loss ( ,effici5cy unless ! gap betwe5 ! top & bottom surfaces is equal to n less ?an #a #a_/b times ! *ord4 ,if less ?an t1 ! air engag$ by ! bottom ( ! top surface w h a t5d5cy to be drawn into ! r>efi$ area ov] ! top ( ! bottom surface1 ) ! result t ! surfaces w n secure z good a reaction z w\ld o!rwise be ! case4 ,x is n practicable to h a gap ( mu* m ?an a di/ance equal to ! *ord1 ow+ to ! drift produc$ by ! great l5g? ( /ruts & wires su* a l>ge gap w\ld necessitate4 ,by /agg]+ ! top surface =w>d1 h[ev]1 x is remov$ f ! action ( ! l[] surface & engages undi/urb$ air1 ) ! result t ! effici5cy c 9 ?is way be increas$ by ab\t #e p] c5t4 ,!oretically ! top plane %\ld be /agg]$ =w>d = a di/ance equal to ab\t #cj p] c5t4 ( ! *ord1 ! exact di/ance dep5d+ ^u ! velocity & angle ( incid5ce2 b ?is is n always possible to arrange 9 design+ an a]oplane1 ow+ to difficulties ( balance1 desir$ position1 & view ( pilot1 obs]v]1 etc4 #f4 ,horizontal ,equival5t4--,! v]tical compon5t ( ! reaction1 i4e41 lift1 v>ies z ! horizontal equival5t 7,h4,e47 ( ! surface1 b ! drift rema9s ! same4 ,!n x foll[s t if ,h4,e4 gr[s less1 ! ratio ( lift to drift mu/ d ! same4 ,a1 ,b1 & ,c are front views ( ?ree surfaces4 ,a has its full ,h4,e41 & !re=e1 f ! po9t ( view f :i* we are at ! mom5t consid]+ effici5cy1 x has its be/ lift-drift ratio4 ,b & ,c bo? possess ! same surface z ,a1 b "o is incl9$ upw>ds f its c5tre & ! o!r is /raight b tilt$4 ,= ^! reasons _! ,h4,e4's are1 z illu/rat$1 less ?an 9 ! case ( ,a4 ,t means less v]tical lift1 &1 ! drift rema9+ ! same 7= !re is ! same am\nt ( surface z 9 ,a to produce x71 ! lift-drift ratio falls4 ,,! ,,m>g9 ,,( ,,p[] is ! p[] available above t necess>y to ma9ta9 horizontal flight4 ,,! ,,m>g9 ,,( ,,lift is ! height an a]oplane c ga9 9 a giv5 "t & />t+ f a giv5 altitude4 ,z an example1 ?us3 #a1jjj feet ! fir/ m9ute1 & />t+ f an altitude ( #ejj feet above sea-level4 ,! m>g9 ( lift decreases ) altitude1 ow+ to ! decrease 9 ! d5sity ( ! air1 :i* adv]sely affects ! eng9e4 ,provid$ ! eng9e ma9ta9$ its impulse ) altitude1 !n1 if we ignore ! problem ( ! propell]1 :i* ,i w g into lat] on1 ! m>g9 ( lift w\ld n disappe>4 ,moreov]1 great] velocity = a giv5 p[] w\ld be secur$ at a great] altitude1 ow+ to ! decreas$ d5sity ( air to be ov]come4 ,aft] read+ t1 y may l to light y\r pipe & indulge 9 dreams ( ! wond]ful possibilities :i* may become realities if "s brilliant g5ius %[s u "s day h[ to secure a con/ant p[] ) increas+ altitude4 ,i am afraid1 h[ev]1 t w always rema9 impossible2 b x is probable t "s v int]e/+ /eps may be tak5 9 t direction4 ,,! ,,m9imum ,,angle ,,( ,,incid5ce is ! smalle/ angle at :i*1 = a giv5 p[]1 surface 7includ+ detrim5tal surface71 & weight1 horizontal flight c be ma9ta9$4 ,,! ,,maximum ,,angle ,,( ,,incid5ce is ! greate/ angle at :i*1 = a giv5 p[]1 surface 7includ+ detrim5tal surface71 & weight1 horizontal flight c be ma9ta9$4 ,,! ,,optimum ,,angle ,,( ,,incid5ce is ! angle at :i* ! lift-drift ratio is highe/4 ,9 mod]n a]oplanes x is t angle ( incid5ce possess$ by ! surface :5 ! axis ( ! propell] is horizontal4 ,,! ,,be/ ,,climb+ ,,angle is approximately half-way betwe5 ! maximum & ! optimum angles4 ,all pres5t-day a]oplanes are a compromise betwe5 ,climb & horizontal ,velocity4 ,we w comp>e ! ess5tials = two a]oplanes1 "o design$ = maximum climb1 & ! o!r = maximum velocity4 ,,ess5tials ,,= ,,maximum ,,climb3 #a4 ,l[ velocity1 9 ord] to secure ! be/ lift-drift ratio4 #b4 ,hav+ a l[ velocity1 a l>ge surface w be necess>y 9 ord] to engage ! necess>y mass ( air to secure ! requisite lift4 #c4 ,s9ce 7#a7 su* a climb+ ma*9e w move along an upw>d slop+ pa?1 & 7#b7 w climb ) its propell] ?ru/ horizontal1 !n a l>ge angle relative to ! direction ( ! ?ru/ w be necess>y 9 ord] to secure ! requisite angle relative to ! direction ( motion4 ,! propell] ?ru/ %\ld be always horizontal1 because ! mo/ effici5t fly+-ma*9e 7hav+ reg>d to climb ,,or velocity7 has1 s f>1 be5 f\nd to be an arrangem5t ( an incl9$ surface driv5 by a ,,horizontal ?ru/--! surface lift+ ! weight1 & ! ?ru/ ov]com+ ! drift4 ,?is is1 9 practice1 a f> m effici5t arrangem5t ?an ! helicopt]1 i4e41 ! air-screw revolv+ ab\t a v]tical axis & produc+ a ?ru/ oppos$ to gravity4 ,if1 :5 climb+1 ! propell] ?ru/ is at su* an angle z to t5d to haul ! a]oplane upw>ds1 !n x is1 9 a measure1 act+ z a helicopt]1 & t means ineffici5cy4 ,! reason ( a helicopt] be+ ineffici5t 9 practice is due to ! fact t1 ow+ to me*anical difficulties1 x is impossible to con/ruct )9 a reasonable weight an air-screw ( ! requisite dim5sions4 ,t be+ s1 x w\ld be necess>y1 9 ord] to absorb ! p[] ( ! eng9e1 to revolve ! comp>atively small-surfac$ air screw at an imm5sely great] velocity ?an t ( ! a]oplane's surface4 ,z already expla9$1 ! lift-drift ratio falls ) velocity on acc\nt ( ! increase 9 passive drift4 ,?is applies to a blade ( a propell] or air-screw1 :i* is no?+ b a revolv+ surface set at angle ( incid5ce1 & :i* x is impossible to con/ruct )\t a good deal ( detrim5tal surface ne> ! c5tral boss4 #d4 ,! velocity be+ l[1 !n x foll[s t = t reason also ! angle ( incid5ce %\ld be comp>atively l>ge4 #e4 ,camb]4--,s9ce su* an a]oplane w\ld be ( l[ velocity1 & !re=e possess a l>ge angle ( incid5ce1 a l>ge camb] w\ld be necess>y4 ,let u n[ consid] ! ess5tials = an a]oplane ( maximum velocity = its p[]1 & possess+ m]ely en\gh lift to get (f ! gr\nd1 b no m>g9 ( lift4 #a4 ,comp>atively ,,high ,,velocity4 #b4 ,a comp>atively ,,small ,,surface1 because1 be+ ( great] velocity ?an ! maximum climb]1 a great] mass ( air w be engag$ = a giv5 surface & "t1 & !re=e a small] surface w be suffici5t to secure ! requisit lift4 #c4 ,a small angle relative to ! propell] ?ru/1 s9ce ! latt] co9cides ) ! direction ( motion4 #d4 ,a comp>atively small angle ( incid5ce by reason ( ! high velocity4 #e4 ,a comp>atively small camb] foll[s z a result ( ! small angle ( incid5ce4 ,,summ>y4 ,ess5tials = ,maximum ,ess5tials = ,maximum ,climb4 ,velocity #a4 ,l[ velocity4 ,high velocity4 #b4 ,l>ge surface4 ,small surface4 #c4 ,l>ge angle relative to ,small angle relative to propell] ?ru/4 propell] ?ru/4 #d4 ,l>ge angle relative to ,small angle relative to direction direction ( motion4 ( motion4 #e4 ,l>ge camb]4 ,small camb]4 ,x is me*anically impossible to con/ruct an a]oplane ( reasonable weight ( :i* x w\ld be possible to v ! above oppos+ ess5tials4 ,!re=e1 all a]oplanes are design$ z a compromise betwe5 ,climb & ,velocity4 ,z a rule a]oplanes are design$ to h at l[ altitude a slight m>g9 ( lift :5 ! propell] ?ru/ is horizontal4 ,,angles ,,( ,,incid5ce 7,,indicat$ ,,approximately7 ,,( ,,an ,,a]oplane ,,design$ ,,z ,a ,,compromise ,,betwe5 ,,velocity ,,& ,,climb1 ,,& ,,possess+ ,a ,,slight ,,m>g9 ,,( ,,lift ,,at ,a ,,l[ ,,altitude ,,& ,,:5 ,,! ,,?ru/ ,,is ,,horizontal ,,m9imum ,,angle4 ,?is gives ! greate/ velocity dur+ horizontal flight at a l[ altitude4 ,great] velocity w\ld be secur$ if ! surface1 angle1 & camb] 7 small] & design$ to j ma9ta9 horizontal flight ) a horizontal ?ru/4 ,also1 9 su* case1 ! propell] w\ld n be ?ru/+ d[nw>ds1 b along a horizontal l9e :i* is obvi\sly a m effici5t arrangem5t if we reg>d ! a]oplane m]ely f "o po9t ( view1 i4e41 ei!r ) ref]5ce to velocity ,,or climb4 ,,optimum ,,angle 7,?ru/ horizontal7 ,! velocity is less ?an at ! small] m9imum angle1 &1 z a]oplanes are design$ to-day1 ! area & angle ( incid5ce ( ! surface is su* z to secure a slight asc5t at a l[ altitude4 ,! camb] ( ! surface is design$ = ?is angle ( incid5ce & velocity4 ,! lift-drift ratio is be/ at ?is angle4 ,,be/ ,,climb+ ,,angle ,! velocity is n[ /ill less by reason ( ! increas$ angle produc+ increase ( drift4 ,less velocity at ,a ,,giv5 ,,angle produces less lift1 b ! increas$ angle m or less (fsets ! loss ( lift due to ! decreas$ velocity1 & 9 addition1 ! ?ru/ is n[ haul+ ! a]oplane upw>ds4 ,,maximum ,,angle ,! great] angle has n[ produc$ s mu* drift z to less5 ! velocity to a po9t :]e ! comb9$ lifts f ! surface & f ! ?ru/ are only j able to ma9ta9 horizontal flight4 ,any great] angle w result 9 a /ill l[] lift-drift ratio4 ,! lift w !n become less ?an ! weight & ! a]oplane w consequ5tly fall4 ,su* a fall is kn[n z 8/all+0 or 8pancak+40 ,,note4--,! gold5 rule = beg9n]s3 ,nev] exce$ ! ,be/ ,climb+ ,angle4 ,always ma9ta9 ! fly+ spe$ ( ! a]oplane4 ,by ?is means1 :5 ! altitude is rea*$ :]e ! m>g9 ( lift disappe>s 7on acc\nt ( loss ( eng9e p[]71 & :i* is1 consequ5tly1 ! altitude :]e x is j possible to ma9ta9 horizontal flight1 ! a]oplane is fly+ ) its ?ru/ horizontal & ) maximum effici5cy 7z di/9ct f eng9e & propell] effici5cy74 ,! m>g9 ( lift at l[ altitude1 & :5 ! ?ru/ is horizontal1 %\ld !n be su* t ! high] altitude at :i* ! m>g9 ( lift is lo/ is t altitude at :i* mo/ ( ! a]oplane's horizontal flight "w is done4 ,t ensures maximum velocity :5 mo/ requir$4 ,un=tunately1 :]e a]oplanes design$ = fight+ are conc]n$1 ! altitude :]e mo/ ( ! "w is done is t at :i* bo? maximum velocity & maximum m>g9 ( lift = p[] are requir$4 ,p]haps "s day a brilliant inv5tor w design an a]oplane ( reasonable weight & drift ( :i* x w be possible = ! pilot to v>y at w ! above-m5tion$ oppos+ ess5tials4 ,!n we %all get maximum velocity1 or maximum m>g9 ( lift1 = p[] z requir$4 ,until !n ! design ( ! a]oplane mu/ rema9 a compromise betwe5 ,velocity & ,climb4 ,,*apt] ,,ii4 ,,/ability ,,& ,,control ,,/ability is a condition :]eby an object di/urb$ has a natural t5d5cy to return to its fir/ & normal position4 ,example3 a weight susp5d$ by a cord4 ,,in/ability is a condition :]eby an object di/urb$ has a natural t5d5cy to move z f> z possible away f its fir/ position1 ) no t5d5cy to return4 ,example3 a /ick balanc$ v]tically ^u y\r f+]4 ,,neutral ,,in/ability is a condition :]eby an object di/urb$ has no t5d5cy to move f>!r ?an displac$ by ! =ce ( ! di/urbance1 & no t5d5cy to return to its fir/ position4 ,9 ord] t an a]oplane may be reasonably controllable1 x is necess>y = x to possess "s degree ( /ability longitud9ally1 lat]ally1 & directionally4 ,,longitud9al ,,/ability 9 an a]oplane is its /ability ab\t an axis transv]se to ! direction ( normal horizontal flight1 & )\t :i* x w\ld pit* & toss4 ,,lat]al ,,/ability is its /ability ab\t its longitud9al axis1 & )\t :i* x w\ld roll sideways4 ,,directional ,,/ability is its /ability ab\t its v]tical axis1 & )\t :i* x w\ld h no t5d5cy to keep its c\rse4 ,= su* directional /ability to exi/ !re mu/ be1 9 effect1#af m 8keel-surface0 beh9d ! v]tical axis ?an !re is 9 front ( x4 ,by keel-surface ,i mean e-?+ to be se5 :5 look+ at an a]oplane f ! side ( x--! sides ( ! body1 und]c>riage1 /ruts1 wires1 etc4 ,! same ?+ applies to a wea!rcock4 ,y "k :at w\ld happ5 if !re 0 insuffici5t keel-surface beh9d ! v]tical axis ^u :i* x is pivot$4 ,x w\ld turn (f its prop] c\rse1 :i* is opposite to ! direction ( ! w9d4 ,x is v mu* ! same 9 ! case ( an a]oplane4 ,! above illu/ration repres5ts an a]oplane 7directionally /able7 fly+ along ! c\rse ,b4 ,a gu/ /rik+ x z indicat$ acts ^u ! great] proportion ( keel-surface beh9d ! turn+ axis & ?r[s x into ! new c\rse4 ,x does n1 h[ev]1 travel along ! new c\rse1 ow+ to its mom5tum 9 ! direction ,b4 ,x travels1 z long z su* mom5tum la/s1 9 a direction :i* is ! resultant ( ! two =ces ,?ru/ & ,mom5tum4 ,b ! c5tre l9e ( ! a]oplane is po9t+ 9 ! direction ( ! new c\rse4 ,!re=e its attitude1 relative to ! direction ( motion1 is m or less sideways1 & x consequ5tly receives an air pressure 9 ! direction ,c4 ,su* pressure1 act+ ^u ! keel-surface1 presses ! tail back t[>ds its fir/ position 9 :i* ! a]oplane is ^u its c\rse ,b4 ,:at ,i h describ$ is cont9ually go+ on dur+ flight1 b 9 a well-design$ a]oplane su* /abiliz+ movem5ts are1 mo/ ( ! "t1 s slight z to be imp]ceptible to ! pilot4 ,if an a]oplane 0 n /abiliz$ 9 ?is way1 x w\ld n only be cont9ually try+ to leave its c\rse1 b x w\ld also possess a dang]\s t5d5cy to 8nose away0 f ! direction ( ! side gu/s4 ,9 su* case ! gu/ %[n 9 ! above illu/ration w\ld turn ! a]oplane r\nd ! opposite way a v consid]able di/ance2 & ! "r w+1 be+ on ! outside ( ! turn1 w\ld travel ) great] velocity ?an ! left w+4 ,increas$ velocity means increas$ lift2 & s1 ! "r w+ lift+1 ! a]oplane w\ld turn ov] sideways v quickly4 ,,longitud9al ,,/ability4--,flat surfaces are longitud9ally /able ow+ to ! fact t ) decreas+ angles ( incid5ce ! c5tre l9e ( pressure 7,c4,p47 moves =w>d4 ,! ,c4,p4 is a l9e tak5 across ! surface1 transv]se to ! direction ( motion1 & ab\t :i* all ! air =ces may be said to balance1 or ?r\gh :i* !y may be said to act4 ,imag9e ,a to be a flat surface1 attitude v]tical1 travell+ ?r\gh ! air 9 ! direction ( motion ,m4 ,its ,c4,p4 is !n obvi\sly along ! exact c5tre l9e ( ! surface z illu/rat$4 ,9 ,b1 ,c1 & ,d ! surfaces are %[n ) angles ( incid5ce decreas+ to no?+1 & y w note t ! ,c4,p4 moves =w>d ) ! decreas+ angle4 ,n[1 %\ld "s gu/ or eddy t5d to make ! surface decrease ! angle1 i4e41 dive1 !n ! ,c4,p4 moves =w>d & pu%es ! front ( ! surface up4 ,%\ld ! surface t5d to assume too l>ge an angle1 !n ! rev]se happ5s--! ,c4,p4 moves back & pu%es ! re> ( ! surface up4 ,flat surfaces are1 !n1 !oretically /able longitud9ally4 ,!y are n1 h[ev]1 us$1 on acc\nt ( _! poor lift-drift ratio4 ,z already expla9$1 camb]$ surfaces are us$1 & ^! are longitud9ally un/able at ^? angles ( incid5ce produc+ a reasonable lift-drift ratio1 i4e41 at angles bel[3 ab\t #ab degrees4 ,a is a camb]$ surface1 attitude approximately v]tical1 mov+ ?r\gh ! air 9 ! direction ,m4 ,obvi\sly ! ,c4 ,p4 co9cides ) ! transv]se c5tre l9e ( ! surface4 ,) decreas+ angles1 d[n to angles ( ab\t #cj degrees1 ! ,c4,p4 moves =w>d z 9 ! case ( flat surfaces 7see ,b71 b angles above #cj degrees d n int]e/ u1 s9ce !y produce a v l[ ratio ( lift to drift4 ,bel[ angles ( ab\t #cj degrees 7see ,c7 ! dipp+ front "p ( ! surface assumes a negative angle ( incid5ce result+ 9 ! ,,d[nw>d air pressure ,d1 & ! m ! angle ( incid5ce is decreas$1 ! great] su* negative angle & its resultant pressure ,d4 ,s9ce ! ,c4,p4 is ! resultant ( all ! air =ces1 its position is naturally affect$ by ,d1 :i* causes x to move backw>ds4 ,n[1 %\ld "s gu/ or eddy t5d to make ! surface decrease its angle ( incid5ce1 i4e41 dive1 !n ! ,c4,p4 moves backw>ds1 &1 pu%+ up ! re> ( ! surface1 causes x to dive ! m4 ,%\ld ! surface t5d to assume too l>ge an angle1 !n ! rev]se happ5s2 ! pressure ,d decreases1 ) ! result t ,c4,p4 moves =w>d & pu%es up ! front ( ! surface1 ?us increas+ ! angle /ill fur!r1 ! f9al result be+ a 8tail-slide40 ,x is !re=e necess>y to f9d a means ( /abiliz+ ! naturally un/able camb]$ surface4 ,?is is usually secur$ by means ( a /abiliz+ surface fix$ "s di/ance 9 ! re> ( ! ma9 surface1 & x is a necess>y condition t ! neutral lift l9es ( ! two surfaces1 :5 project$ to meet ea* o!r1 make a dih$ral angle4 ,9 o!r words1 ! re> /abiliz+ surface mu/ h a less] angle ( incid5ce ?an ! ma9 surface--c]ta9ly n m ?an "o-?ird ( t ( ! ma9 surface4 ,?is is kn[n z ! longitud9al dih$ral4 ,i may add t ! tail-plane is sometimes m\nt$ ^u ! a]oplane at ! same angle z ! ma9 surface1 b1 9 su* cases1 x attacks air :i* has receiv$ a d[nw>d deflection f ! ma9 surface1 ?us3 ,! angle at :i* ! tail surface attacks ! air 7! angle ( incid5ce7 is !re=e less ?an ! angle ( incid5ce ( ! ma9 surface4 ,i w n[1 by means ( ! foll[+ illu/ration1 try to expla9 h[ ! longitud9al dih$ral secures /ability3 ,fir/1 imag9e ! a]oplane travell+ 9 ! direction ( motion1 :i* co9cides ) ! direction ( ?ru/ ,t4 ,! weight is1 ( c\rse1 balanc$ ab\t a ,c4,p41 ! resultant ( ! ,c4,p4 ( ! ma9 surface & ! ,c4,p4 ( ! /abiliz+ surface4 ,= ! sake ( illu/ration1 ! /abiliz+ surface has be5 giv5 an angle ( incid5ce1 & !re=e has a lift & ,c4,p4 ,9 practice ! /abiliz] is (t5 set at no angle ( incid5ce4 ,9 su* case ! proposition rema9s ! same1 b x is1 p]haps1 a little easi] to illu/rate x z above4 ,n[1 we w suppose t a gu/ or eddy ?r[s ! ma*9e into ! l[] position4 ,x no long] travels 9 ! direction ( ,t1 s9ce ! mom5tum 9 ! old direction pulls x (f t c\rse4 ,m is n[ ! resultant ( ! ,?ru/ & ! ,mom5tum1 & y w note t ?is results 9 a decrease 9 ! angle our old fri5d ! neutral lift l9e makes ) ,m1 i4e41 a decrease 9 ! angle ( incid5ce & !re=e a decrease 9 lift4 ,we w suppose t ?is decrease is #b degrees4 ,su* decrease applies to bo? ma9 surface & /abiliz]1 s9ce bo? are fix$ rigidly to ! a]oplane4 ,! ma9 surface1 :i* _h #ab degrees angle1 has n[ only #aj degrees1 i4e41 a loss ( ,,"o-,,six?4 ,! /abiliz]1 :i* _h #d degrees angle1 has n[ only #b degrees1 i4e41 a loss ( ,,"o-,,half4 ,! latt] has !re=e lo/ a great] ,,proportion ( its angle ( incid5ce1 & consequ5tly its lift1 ?an has ! ma9 surface4 ,x mu/ !n fall relative to ! ma9 surface4 ,! tail fall+1 ! a]oplane !n assumes its fir/ position1 ?\gh at a slightly less altitude4 ,%\ld a gu/ ?r[ ! nose ( ! a]oplane up1 !n ! rev]se happ5s4 ,bo? ma9 surface & /abiliz] increase _! angles ( incid5ce 9 ! same am\nt1 b ! angle1 & !re=e ! lift1 ( ! /abiliz] increases 9 great] proportion ?an does ! lift ( ! ma9 surface1 ) ! result t x lifts ! tail4 ,! a]oplane !n assumes its fir/ position1 ?\gh at a slightly great] altitude4 ,d n fall into ! widespread error t ! angle ( incid5ce v>ies z ! angle ( ! a]oplane to ! horizontal4 ,x v>ies ) su* angle1 b n z any?+ approa*+ x4 ,rememb] t ! /abiliz+ effect ( ! longitud9al dih$ral la/s only z long z !re is mom5tum 9 ! direction ( ! fir/ c\rse4 ,^! /abiliz+ movem5ts are tak+ place all ! "t1 ev5 ?\gh imp]ceptible to ! pilot4 ,a]oplanes h1 9 ! pa/1 be5 built ) a /abiliz+ surface 9 front ( ! ma9 surface in/ead ( at ! re> ( x4 ,9 su* design ! ma9 surface 7:i* is !n ! tail surface z well z ! pr9cipal lift+ surface7 mu/ be set at a less angle ?an ! =w>d /abiliz+ surface1 9 ord] to secure a longitud9al dih$ral4 ,! defect ( su* design lies 9 ! fact t ! ma9 surface mu/ h a c]ta9 angle to lift ! weight--say #e degrees4 ,!n1 9 ord] to secure a suffici5cy ( longitud9al /ability1 x is necess>y to set ! =w>d /abiliz] at ab\t #ae degrees4 ,su* a l>ge angle ( incid5ce results 9 a v poor lift-drift ratio 7& consequ5tly great loss ( effici5cy71 except at v l[ velocities comp>$ ) ! spe$ ( mod]n a]oplanes4 ,at ! "t su* a]oplanes 7 built velocities 7 comp>atively l[1 & ?is defect 02 = t reason1 n suffici5tly appreciat$4 ,9 ! end x kill$ ! 8can>d0 or 8tail-fir/0 design4 ,a]oplanes ( ! ,dunne & simil> types possess no /abiliz+ surface di/9ct f ! ma9 surface1 b !y h a longitud9al dih$ral :i* r5d]s !m /able4 ,! ma9 surface t[>ds ! w+-tips is giv5 a decreas+ angle ( incid5ce & correspond+ camb]4 ,! w+-tips !n act z longitud9al /abiliz]s4 ,?is design ( a]oplane1 :ile v int]e/+1 has n prov$ v practicable1 ow+ to ! foll[+ disadvantages3 7#a7 ,! plan design is n1 f a me*anical po9t ( view1 s s\nd z t ( ! ord9>y a]oplane surface1 :i* is1 9 plan1 a p>allelogram4 ,x is1 !n1 necess>y to make ! /r5g? ( con/ruction great] ?an w\ld o!rwise be ! case4 ,t means extra weight4 7#b7 ,! plan ( ! surface area is su* t ! aspect ratio is n s high z if ! surface 0 arrang$ ) its lead+ edges at "r angles to ! direction ( motion4 ,! l[] ! aspect ratio1 !n1 ! less ! lift4 ,?is design1 !n1 produces less lift = weight ( surface ?an w\ld ! same surface if arrang$ z a p>allelogram4 7#c7 ,9 ord] to secure ! longitud9al dih$ral1 ! angle ( incid5ce has to be v mu* decreas$ t[>ds ! w+-tips4 ,!n1 9 ord] t ! lift-drift ratio may be pres]v$1 !re mu/ be a correspond+ decrease 9 ! camb]4 ,t calls = surface ribs ( v>y+ camb]s1 & results 9 an exp5sive & l5g?y job = ! build]4 7#d7 ,9 ord] to secure directional /ability1 ! surface is1 9 ! c5tre1 arrang$ to dip d[n 9 ! =m ( a ,v1 po9t+ t[>ds ! direction ( motion4 ,%\ld ! a]oplane turn (f its c\rse1 !n its mom5tum 9 ! direction ( its fir/ c\rse causes x to move 9 a direction ! resultant ( ! ?ru/ & ! mom5tum4 ,x !n moves 9 a m or less sideways attitude1 :i* results 9 an air pressure ^u "o side ( ! ,v1 & :i* t5ds to turn ! a]oplane back to its fir/ c\rse4 ,?is arrangem5t ( ! surface results 9 a bad drift4 ,v]tical surfaces at ! w+-tips may also be set at an angle produc+ ! same /abiliz+ effect1 b !y also increase ! drift4 ,! gyroscopic action ( a rot>y eng9e w affect ! longitud9al /ability :5 an a]oplane is turn$ to "r or left4 ,9 ! case ( a ,gnome eng9e1 su* gyroscopic action w t5d to depress ! nose ( ! a]oplane :5 x is turn$ to ! left1 & to elevate x :5 x is turn$ to ! "r4 ,9 mod]n a]oplanes ?is t5d5cy is n suffici5tly important to bo!r ab\t4 ,9 ! old days ( crudely design$ & "u-p[]$ a]oplanes ?is gyroscopic action 0 v m>k$1 & l$ ! majority ( pilots to dislike turn+ an a]oplane to ! "r1 s9ce1 9 do+ s1 !re 0 "s dang] ( 8/all+40 ,,lat]al ,,/ability is f> m difficult = ! design] to secure ?an is longitud9al or directional /ability4 ,"s degree ( lat]al /ability may be secur$ by means ( ! 8lat]al dih$ral10 i4e41 ! upw>d incl9ation ( ! surface t[>ds its w+-tips ?us3 ,imag9e ! top ,v1 illu/rat$ opposite1 to be ! front view ( a surface fly+ t[>ds y4 ,! horizontal equival5t 7,h4,e47 ( ! left w+ is ! same z t ( ! "r w+4 ,!re=e1 ! lift ( "o w+ is equal to ! lift ( ! o!r1 & ! weight1 be+ situat$ always 9 ! c5tre1 is balanc$4 ,if "s movem5t ( ! air causes ! surface to tilt sideways1 z 9 ! l[] illu/ration1 !n y w note t ! ,h4,e4 ( ! left w+ increases1 & ! ,h4,e4 ( ! "r w+ decreases4 ,! left w+ !n1 hav+ ! greate/ lift1 rises2 & ! surface assumes its fir/ & normal position4 ,un=tunately h[ev]1 ! right+ effect is n proportional to ! diff]5ce betwe5 ! "r & left ,h4,e4's4 ,9 ! case ( ,a1 ! resultant direction ( ! reaction ( bo? w+s is oppos$ to ! direction ( gravity or weight4 ,! two =ces ,r ,r & gravity are !n ev5ly balanc$1 & ! surface is 9 a /ate ( equilibrium4 ,9 ! case ( ,b1 y w note t ! ,r ,r is n directly oppos$ to gravity4 ,?is results 9 ! appe>ance ( ,m1 & s ! resultant direction ( motion ( ! a]oplane is no long] directly =w>d1 b is along a l9e ! resultant ( ! ?ru/ & ,m4 ,9 o!r words1 x is1 :ile fly+ =w>d1 at ! same "t mov+ sideways 9 ! direction ,m4 ,9 mov+ sideways1 ! keel-surface receives1 ( c\rse1 a pressure f ! air equal & opposite to ,m4 ,s9ce su* surface is greate/ 9 effect t[>ds ! tail1 !n ! latt] mu/ be pu%$ sideways4 ,t causes ! a]oplane to turn2 &1 ! highe/ w+ be+ on ! outside ( ! turn1 x has a great] velocity ?an ! l[] w+4 ,t produces great] lift1 & t5ds to tilt ! a]oplane ov] /ill m4 ,su* tilt+ t5d5cy is1 h[ev]1 oppos$ by ! diff]5ce 9 ! ,h4,e4's ( ! two w+s4 ,x !n foll[s t1 = ! lat]al dih$ral angle to be effective1 su* angle mu/ be l>ge en\gh to produce1 :5 ! a]oplane tilts1 a diff]5ce 9 ! ,h4,e4's ( ! two w+s1 :i* diff]5ce mu/ be suffici5t to n only oppose ! tilt+ t5d5cy due to ! a]oplane turn+1 b suffici5t to also =ce ! a]oplane back to its orig9al position ( equilibrium4 ,x is n[1 ,i hope1 cle> to ! read] t ! lat]al dih$ral is n q s effective z w\ld appe> at fir/ sight4 ,"s design]s1 inde$1 pref] n to use x1 s9ce its effect is n v great1 & s9ce x mu/ be paid = 9 loss ( ,h4,e4 & consequ5tly loss ( lift1 ?us decreas+ ! lift-drift ratio1 i4e41 ! effici5cy4 ,also1 x is sometimes advanc$ t ! lat]al dih$ral increases ! 8spill0 ( air f ! w+-tips & t ?is adv]sely affects ! lift-drift ratio4 ,! disposition ( ! keel-surface affects ! lat]al /ability4 ,x %\ld be1 9 effect1 equally divid$ by ! longitud9al turn+ axis ( ! a]oplane4 ,if !re is an excess ( keel-surface above or bel[ su* axis1 !n a side gu/ /rik+ x w t5d to turn ! a]oplane ov] sideways4 ,! position ( ! c5tre ( gravity affects lat]al /ability4 ,if too l[1 x produces a p5dulum effect & causes ! a]oplane to roll sideways4 ,if too high1 x acts z a /ick balanc$ v]tically w\ld act4 ,if di/urb$1 x t5ds to travel to a position z f> z possible f its orig9al position4 ,x w\ld !n t5d1 :5 mov$1 to turn ! a]oplane ov] sideways & into an upside-d[n position4 ,f ! po9t ( view ( lat]al /ability1 ! be/ position = ! c5tre ( gravity is "o a little bel[ ! c5tre ( drift4 ,propell] torque affects lat]al /ability4 ,an a]oplane t5ds to turn ov] sideways 9 ! opposite direction to :i* ! propell] revolves4 ,?is t5d5cy is (fset by increas+ ! angle ( incid5ce 7& consequ5tly ! lift7 ( ! side t5d+ to fall2 & x is always advisable1 if practical consid]ations all[ x1 to also decrease ! angle ^u ! o!r side4 ,9 t way x is n necess>y to dep>t s f> f ! normal angle ( incid5ce at :i* ! lift-drift ratio is highe/4 ,wa%-9 is ! t]m appli$ to ! increas$ angle4 ,wa%-out is ! t]m appli$ to ! decreas$ angle4 ,bo? lat]al & directional /ability may be improv$ by wa%+ out ! angle ( incid5ce on bo? sides ( ! surface1 ?us3 ,! decreas$ angle decreases ! drift & !re=e ! effect ( gu/s ^u ! w+-tips :i* is j :]e !y h ! mo/ effect ^u ! a]oplane1 ow+ to ! di/ance f ! turn+ axis4 ,! wa%-out also r5d]s ! ail]ons 7lat]al controll+ s]vices7 m effective1 z1 9 ord] to op]ate !m1 x is n !n necess>y to give !m su* a l>ge angle ( incid5ce z w\ld o!rwise be requir$4 ,! less ! angle ( incid5ce ( ! ail]ons1 ! bett] _! lift-drift ratio1 i4e41 _! effici5cy4 ,y w note t1 :ile ! ail]on atta*$ to ! surface ) wa%$-out angle is op]at$ to ! same ext5t z ! ail]on illu/rat$ above x1 its angle ( incid5ce is consid]ably less4 ,its effici5cy is !re=e great]4 ,! advantages ( ! wa%-9 mu/1 ( c\rse be paid = 9 "s loss ( lift1 z ! lift decreases ) ! decreas$ angle4 ,9 ord] to secure all ! above describ$ advantages1 a comb9ation is sometimes effect$1 ?us3 ,,bank+4--,an a]oplane turn$ (f its c\rse to "r or left does n at once proce$ along its new c\rse4 ,its mom5tum 9 ! direction ( its fir/ c\rse causes x to travel along a l9e ! resultant ( su* mom5tum & ! ?ru/4 ,9 o!r words1 x m or less skids sideways & away f ! c5tre ( ! turn4 ,its lift+ surfaces d n !n meet ! air 9 _! correct attitude1 & ! lift may fall to su* an ext5t z to become less ?an ! weight1 9 :i* case ! a]oplane mu/ fall4 ,?is bad effect is m9imiz$ by 8bank+10 i4e41 tilt+ ! a]oplane sideways4 ,! bottom ( ! lift+ surface is 9 t way oppos$ to ! air ?r\gh :i* x is mov+ 9 ! direction ( ! mom5tum & receives an opposite air pressure4 ,! r>efi$ area ov] ! top ( ! surface is r5d]$ /ill m r>e1 & ?is1 ( c\rse1 assi/s ! air pressure 9 oppos+ ! mom5tum4 ,! velocity ( ! 8skid10 or sideways movem5t1 is !n only su* z is necess>y to secure an air pressure equal & opposite to ! c5trifugal =ce ( ! turn4 ,! %>p] ! turn1 ! great] ! effect ( ! c5trifugal =ce1 & !re=e ! /eep] %\ld be ! 8bank40 ,exp]5tia docet4 ,! position ( ! c5tre ( gravity affects bank+4 ,a l[ ,c4,g4 w t5d to sw+ outw>d f ! c5tre ( ! turn1 & w cause ! a]oplane to bank--p]haps too mu*1 9 :i* case ! pilot mu/ rem$y matt]s by op]at+ ! ail]ons4 ,a high ,c4,g4 also t5ds to sw+ outw>d f ! c5tre ( ! turn4 ,x w t5d to make ! a]oplane bank ! wrong way1 & su* effect mu/ be rem$i$ by means ( ! ail]ons4 ,! pleasante/ ma*9e f a bank+ po9t ( view is "o 9 :i* ! ,c4,g4 is a little bel[ ! c5tre ( drift4 ,x t5ds to bank ! a]oplane ! "r way = ! turn1 & ! pilot c1 if necess>y1 p]fect ! bank by means ( ! ail]ons4 ,! disposition ( ! keel-surface affects bank+4 ,x %\ld be1 9 effect1 ev5ly divid$ by ! longitud9al axis4 ,an excess ( keel-surface above ! longitud9al axis w1 :5 bank+1 receive an air pressure caus+ ! a]oplane to bank1 p]haps too mu*4 ,an excess ( keel-surface bel[ ! axis has ! rev]se effect4 ,,side-,,slipp+4--,?is usually occurs z a result ( ov]-bank+4 ,x is always ! result ( ! a]oplane tilt+ sideways & ?us decreas+ ! horizontal equival5t1 & !re=e ! lift1 ( ! surface4 ,an excessive 8bank10 or sideways tilt1 results 9 ! ,h4,e41 & !re=e ! lift1 becom+ less ?an ! weight1 :51 ( c\rse1 ! a]oplane mu/ fall1 i4e41 side-slip4 ,:5 mak+ a v %>p turn x is necess>y to bank v /eeply inde$4 ,if1 at ! same "t1 ! longitud9al axis ( ! a]oplane rema9s approximately horizontal1 !n !re mu/ be a fall1 & ! direction ( motion w be ! resultant ( ! ?ru/ & ! fall z illu/rat$ above 9 sket* ,a4 ,! lift+ surfaces & ! controll+ surfaces are n !n meet+ ! air 9 ! correct attitude1 ) ! result t1 9 addition to fall+1 ! a]oplane w probably become q unmanageable4 ,! ,pilot1 h[ev]1 prev5ts su* a /ate ( affairs f happ5+ by 8nos+-d[n10 i4e41 by op]at+ ! rudd] to turn ! nose ( ! a]oplane d[nw>d & t[>ds ! direction ( motion z illu/rat$ 9 sket* ,b4 ,?is results 9 ! high] w+1 :i* is on ! outside ( ! turn1 travell+ ) great] velocity1 & !re=e secur+ a great] reaction ?an ! l[] w+1 ?us t5d+ to tilt ! a]oplane ov] /ill m4 ,! a]oplane is n[ almo/ upside-d[n1 b its attitude relative to ! direction ( motion is correct & ! controll+ surfaces are all ( !m work+ effici5tly4 ,! recov]y ( a normal attitude relative to ! ,e>? is !n made z illu/rat$ 9 sket* ,c4 ,! ,pilot mu/ !n le>n to "k j ! angle ( bank at :i* ! m>g9 ( lift is lo/1 &1 if a %>p turn necessitates bank+ beyond t angle1 he mu/ 8nose-d[n40 ,9 ?is matt] ( bank+ & nos+-d[n1 &1 inde$1 reg>d+ /ability & control g5]ally1 ! gold5 rule = all b v exp]i5c$ pilots %\ld be3 ,keep ! a]oplane 9 su* an attitude t ! air pressure is always directly 9 ! pilot's face4 ,! a]oplane is !n always engag+ ! air z design$ to d s1 & bo? lift+ & controll+ surfaces are act+ effici5tly4 ,! only exception to ?is rule is a v]tical dive1 & ,i ?9k t is obvi\sly n an attitude = any b v exp]i5c$ pilots to hank] aft]4 ,,sp9n+4--,?is is ! wor/ ( all pr$icam5ts ! pilot c f9d himself 94 ,=tunately x r>ely happ5s4 ,x is due to ! comb9ation ( 7#a7 a v /eep spiral desc5t ( small radius1 & 7#b7 insuffici5cy ( keel-surface beh9d ! v]tical axis1 or ! jamm+ ( ! rudd] end or elevator into a position by :i* ! a]oplane is =c$ into an increas+ly /eep & small spiral4 ,ow+ to ! small radius ( su* a spiral1 ! mass ( ! a]oplane may ga9 a rot>y mom5tum great]1 9 effect1 ?an ! air pressure ( ! keel-surface or controll+ surfaces oppos$ to x2 &1 :5 once su* a condition occurs1 x is difficult to see :at c be done by ! pilot to rem$y x4 ,! s5sible pilot w n g beyond reasonable limits ( /eepness & radius :5 execut+ spiral desc5ts4 ,,glid+ ,,desc5t ,,)\t ,,propell] ,,?ru/4--,all a]oplanes are1 or %\ld be1 design$ to assume _! glid+ angle :5 ! p[] & ?ru/ is cut (f4 ,?is relieves ! pilot ( "w1 worry1 & dang] %\ld he f9d himself 9 a fog or cl\d4 ,! ,pilot1 al?\gh he may n realize x1 ma9ta9s ! correct attitude ( ! a]oplane by obs]v+ its position relative to ! horizon4 ,fly+ into a fog or cl\d ! horizon is lo/ to view1 & he mu/ !n rely ^u 8 in/rum5ts--7#a7 ! compass = direction2 7#b7 an incl9omet] 7ar*$ _s-level7 m\nt$ transv]sely to ! longitud9al axis1 = lat]al /ability2 & 7#c7 an incl9omet] m\nt$ p>allel to ! longitud9al axis1 or ! airspe$ indicator1 :i* w indicate a nose-d[n position by increase 9 air spe$1 & a tail-d[n position by decrease 9 air spe$4 ,! pilot is !n "u ! necessity ( wat*+ ?ree in/rum5ts & manipulat+ 8 ?ree controls to keep ! in/rum5ts indicat+ longitud9al1 lat]al1 & directional /ability4 ,t is a feat beyond ! capacity ( ! ord9>y man4 ,if1 h[ev]1 by ! simple movem5t ( ?rottl+ d[n ! p[] & ?ru/1 he c be reliev$ ( look+ aft] ! longitud9al /ability1 he !n has only two in/rum5ts to wat*4 ,t is no small job 9 itself1 b x is1 at any rate1 fairly practicable4 ,a]oplanes are1 !n1 design$1 or %\ld be1 s t ! c5tre ( gravity is slightly =w>d ( c5tre ( lift4 ,! a]oplane is !n1 z a glid]1 nose-heavy--& ! di/ance ! ,c4,g4 is plac$ 9 advance ( ! ,c4,l4 %\ld be su* z to ensure a glid+ angle produc+ a velocity ! same z ! normal fly+ spe$ 7= :i* ! /r5g? ( con/ruction has be5 design$74 ,9 ord] t ?is nose-heavy t5d5cy %\ld n exi/ :5 ! ?ru/ is work+ & desc5t n requir$1 ! c5tre ( ?ru/ is plac$ a little bel[ ! c5tre ( drift or resi/ance1 & ?us t5ds to pull up ! nose ( ! a]oplane4 ,! di/ance ! c5tre ( ?ru/ is plac$ bel[ ! c5tre ( drift %\ld be su* z to produce a =ce equal & opposite to t due to ! ,c4,g4 be+ =w>d ( ! ,c4,l4 ,,loop+ ,,& ,,upside ,,d[n ,,fly+4--,if a loop is desir$1 x is be/ to ?rottle ! eng9e d[n at po9t ,a4 ,! ,c4,g4 be+ =w>d ( ! ,c4,p41 !n causes ! a]oplane to nose-d[n1 & assi/s ! pilot 9 mak+ a reasonably small loop along ! c\rse ,c & 9 secur+ a quick recov]y4 ,if ! eng9e is n ?rottl$ d[n1 !n ! a]oplane may be expect$ to foll[ ! c\rse ,d1 :i* results 9 a long] nose dive ?an 9 ! case ( ! c\rse ,c4 ,a /eady1 g5tle movem5t ( ! elevator is necess>y4 ,a j]ky movem5t may *ange ! direction ( motion s sudd5ly z to produce dang]\s air /resses ^u ! surfaces1 9 :i* case !re is a possibility ( collapse4 ,if an upside-d[n flight is desir$1 ! eng9e may1 or may n1 be ?rottl$ d[n at po9t ,a4 ,if n ?rottl$ d[n1 !n ! elevator mu/ be op]at$ to secure a c\rse approximately 9 ! direction ,b4 ,if x is ?rottl$ d[n1 !n ! c\rse mu/ be "o ( a /eep] angle ?an ,b1 or !re w be dang] ( /all+4 ,diagram p4 #hh4--,?is is n set at q ! correct angle4 ,pa? ,b %\ld slope slightly d[nw>ds f ,position ,a4 ,,*apt] ,,iii4 ,,rigg+ ,9 ord] to rig an a]oplane intellig5tly1 & to ma9ta9 x 9 an effici5t & safe condition1 x is necess>y to possess a k ( ! /resses x is call$ ^u to endure1 & ! /ra9s likely to appe>4 ,,/ress is ! load or burd5 a body is call$ ^u to be>4 ,x is usually express$ by ! result f\nd by divid+ ! load by ! numb] ( sup]ficial squ>e in*es conta9$ 9 ! cross-sectional area ( ! body4 ,?us1 if1 = in/ance1 ! object illu/rat$ above conta9s #d squ>e in*es ( cross-sectional area1 & ! total load x is call$ ^u to endure is #aj tons1 ! /ress w\ld be express$ z #b #a_/b tons4 ,,/ra9 is ! de=mation produc$ by /ress4 ,,! ,,factor ,,( ,,safety is usually express$ by ! result f\nd by divid+ ! /ress at :i* x is kn[n ! body w collapse1 by ! maximum /ress x w be call$ ^u to endure4 ,= in/ance1 if a control wire be call$ ^u to endure a maximum /ress ( #b cwts41 & ! kn[n /ress at :i* x w collapse is #aj cwts41 ! factor ( safety is !n #e4 cwts4 c5t]weights #ajj p\nd units z 9 c5t c5tury4 ,int]e/+ly en\gh1 ?is ^w only exi/s today 9 abbreviation =m1 probably ( c5treweights1 b ! diction>y entries1 ev5 f a hundr$ ye>s ago d n li/ ?is z a ^w1 b d li/ c4 or ,c4 z ! previ\s popul> abbreviation z 9 ,roman ,num]als ,! ^w li/$ is 8hundr$weight4 ,mi*ael ,s4 ,h>t1 #aiig ,,compression4--,! simple /ress ( compression t5ds to produce a cru%+ /ra94 ,example3 ! int]plane & fuselage /ruts4 ,,t5sion4--,! simple /ress ( t5sion t5ds to produce ! /ra9 ( elongation4 ,example3 all ! wires4 ,,b5d+4--,! comp\nd /ress ( b5d+ is a comb9ation ( compression & t5sion4 ,! above sket* illu/rates a /raight piece ( wood ( :i* ! top1 c5tre1 & bottom l9es are ( equal l5g?4 ,we w n[ imag9e x b5t to =m a circle1 ?us3 ,! c5tre l9e is /ill ! same l5g? z be=e be+ b5t2 b ! top l9e1 be+ f>!r f ! c5tre ( ! circle1 is n[ long] ?an ! c5tre l9e4 ,t c be due only to ! /ra9 ( elongation produc$ by ! /ress ( t5sion4 ,! wood betwe5 ! c5tre l9e & ! top l9e is !n 9 t5sion2 & ! f>!r f ! c5tre1 ! great] ! /ra91 & consequ5tly ! great] ! t5sion4 ,! bottom l9e1 be+ ne>e/ to ! c5tre ( ! circle1 is n[ %ort] ?an ! c5tre l9e4 ,t c be due only to ! /ra9 ( cru%+ produc$ by ! /ress ( compression4 ,! wood betwe5 ! c5tre & bottom l9es is !n 9 compression2 & ! ne>] ! c5tre ( ! circle1 ! great] ! /ra91 & consequ5tly ! great] ! compression4 ,x !n foll[s t !re is nei!r t5sion nor compression1 i4e41 no /ress1 at ! c5tre l9e1 & t ! wood imm$iately surr\nd+ x is "u consid]ably less /ress ?an ! wood f>!r away4 ,?is be+ s1 ! wood 9 ! c5tre may be holl[$ out )\t unduly weak5+ /ruts & sp>s4 ,9 ?is way #be to #cc p] c5t4 is sav$ 9 ! weight ( wood 9 an a]oplane4 ,! /r5g? ( wood is 9 its fibres1 :i* %\ld1 z f> z possible1 run )\t break f "o end ( a /rut or sp> to ! o!r end4 ,a po9t to rememb] is t ! outside fibres1 be+ f>!/ remov$ f ! c5tre l9e1 are do+ by f> ! greate/ "w4 ,,%e> ,,/ress ,,is su* t1 :5 mat]ial collapses "u x1 "o "p slides ov] ! o!r4 ,example3 all ! lock+ p9s4 ,"s ( ! bolts are also 9 %e> or 8sideways0 /ress1 ow+ to lugs "u _! heads & f :i* wires are tak54 ,su* a wire1 ex]t+ a sideways pull ^u a bolt1 tries to break x 9 su* a way z to make "o piece ( ! bolt slide ov] ! o!r piece4 ,,torsion4--,?is is a twi/+ /ress comp\nd$ ( compression1 t5sion1 & %e> /resses4 ,example3 ! propell] %aft4 ,,nature ,,( ,,wood ,,"u ,,/ress4--,wood1 = its weight1 takes ! /ress ( compression f> bett] ?an any o!r /ress4 ,= in/ance3 a walk+-/ick ( less ?an #a lb4 9 weight w1 if kept p]fectly /raight1 probably /& up to a compression /ress ( a ton or m be=e cru%+2 :]eas1 if ! same /ick is put "u a b5d+ /ress1 x w probably collapse to a /ress ( n m ?an ab\t #ej lb4 ,t is a v great diff]5ce1 &1 s9ce weight is ( ! greate/ importance1 ! design ( an a]oplane is always su* z to1 z f> z possible1 keep ! v>i\s wood5 p>ts ( its con/ruction 9 direct compression4 ,weight be+ ( su* vital importance1 & design]s all try+ to outdo ea* o!r 9 sav+ weight1 x foll[s t ! factor ( safety is r l[ 9 an a]oplane4 ,! p>ts 9 direct compression w1 h[ev]1 take ! /resses safely provid$ ! foll[+ conditions are c>efully obs]v$4 ,,conditions ,,to ,,be ,,obs]v$3 #a4 ,all ! sp>s & /ruts mu/ be p]fectly /raight4 ,! above sket* illu/rates a section ?r\gh an int]plane /rut4 ,if ! /rut is to be kept /raight1 i4e41 prev5t$ f b5d+1 !n ! /ress ( compression mu/ be equally dispos$ ab\t ! c5tre ( /r5g?4 ,if x is n /raight1 !n !re w be m compression on "o side ( ! c5tre ( /r5g? ?an on ! o!r side4 ,t is a /ep t[>ds gett+ compression on "o side & t5sion on ! o!r side1 9 :i* case x may be =c$ to take a b5d+ /ress = :i* x is n design$4 ,ev5 if x does n collapse x w1 9 effect1 become %ort]1 & ?us ?r[ out ( adju/m5t ! gap & all ! wires atta*$ to ! top & bottom ( ! /rut1 ) ! result t ! flight effici5cy ( ! a]oplane w be spoil$4 ,! only exception to ! above condition is :at is kn[n z ! ,ar*4 ,= in/ance1 9 ! case ( ! ,maurice ,f>man1 ! sp>s ( ! c5tre-section plane1 :i* h to take ! weight ( ! nacelle1 are ar*$ upw>ds4 ,if ?is 0 n done1 x is possible t r\gh l&+s might result 9 ! weight caus+ ! sp>s to become slightly di/ort$ d[nw>ds4 ,t w\ld produce a dang]\s b5d+ /ress1 b1 z long z ! wood is ar*$1 or1 at any rate1 kept f b5d+ d[nw>ds1 x w rema9 9 direct compression & no dang] c result4 #b4 ,/ruts & sp>s mu/ be symmetrical4 ,by t ,i mean t ! cross-sectional dim5sions mu/ be correct1 z o!rwise !re w be bulg+ places on ! outside1 ) ! result t ! /ress w n be ev5ly dispos$ ab\t ! c5tre ( /r5g?1 & a b5d+ /ress may be produc$4 #c4 ,/ruts1 sp>s1 etc41 mu/ be undamag$4 ,rememb] t1 f :at ,i h already expla9$ ab\t b5d+ /resses1 ! outside fibres ( ! wood are do+ by f> ! mo/ "w4 ,if ^! get bruis$ or scor$1 !n ! /rut or sp> suff]s 9 /r5g? mu* m ?an "o might ?9k at fir/ sight2 &1 if x ev] gets a t5d5cy to b5d1 x is likely to collapse at t po9t4 #d4 ,! wood mu/ h a good1 cle> gra9 ) no cross-gra91 knots1 or %akes4 ,su* blemi%es produce weak places &1 if a t5d5cy to b5d appe>s1 !n x may collapse at su* a po9t4 #e4 ,! /ruts1 sp>s1 etc41 mu/ be prop]ly b$d$ into _! sockets or fitt+s4 ,to beg9 )1 !y mu/ be ( good pu%+ or g5tle tapp+ fit4 ,!y mu/ nev] be driv5 9 ) a heavy hamm]4 ,!n aga91 a /rut mu/ b$ well d[n all ov] its cross-sectional area z illu/rat$ above2 o!rwise ! /ress ( compression w n be ev5ly dispos$ ab\t ! c5tre ( /r5g?1 & t may produce a b5d+ /ress4 ,! bottom ( ! /rut or sp> %\ld be cov]$ ) "s sort ( pa9t1 b$d$ into ! socket or fitt+1 & !n )drawn to see if ! pa9t has /uck all ov] ! b$4 #f4 ,! atmosph]e is sometimes mu* damp] ?an at o!r times1 & ?is causes wood to exp& & contract appreciably4 ,?is w\ld n matt] b = ! fact t x does n exp& & contract uni=mly1 b becomes unsymmetrical1 i4e41 di/ort$4 ,i h already expla9$ ! dang] ( t 9 condition #b4 ,?is %\ld be m9imiz$ by ,,well ,,v>ni%+ ,,! ,,wood to keep ! moi/ure out ( x4 ,,function ,,( ,,int]plane ,,/ruts4--,^! /ruts h to keep ! lift+ surfaces or 8planes0 ap>t1 b ?is is only "p ( _! "w4 ,!y mu/ keep ! planes ap>t1 s t ! latt] are 9 _! correct attitude4 ,t is only s :5 ! sp>s ( ! bottom plane are p>allel ) ^? ( ! top plane4 ,also1 ! *ord ( ! top plane mu/ be p>allel ) ! *ord ( ! bottom plane4 ,if t is n s1 !n "o plane w n h ! same angle ( incid5ce z ! o!r "o4 ,at fir/ sight "o might ?9k t all t is necess>y is to cut all ! /ruts to be ! same l5g?1 b t is n ! case4 ,sometimes1 z illu/rat$ above1 ! re> sp> is n s ?ick z ! ma9 sp>1 & x is !n necess>y to make up = t diff]5ce by mak+ ! re> /ruts correspond+ly long]4 ,if t is n done1 !n ! top & bottom *ords w n be p>allel1 & ! top & bottom planes w h diff]5t angles ( incid5ce4 ,also1 ! sockets or fitt+s1 or ev5 ! sp>s ^u :i* !y are plac$1 sometimes v>y 9 ?ickness ow+ to faulty manufacture4 ,?is mu/ be (fset by alt]+ ! l5g? ( ! /ruts4 ,! be/ way to proce$ is to measure ! di/ance betwe5 ! top & bottom sp>s by ! side ( ea* /rut1 & if t di/ance1 or 8gap0 z x is call$1 is n z /at$ 9 ! a]oplane's specifications1 !n make x correct by *ang+ ! l5g? ( ! /rut4 ,?is applies to bo? front & re> int]plane /ruts4 ,:5 measur+ ! gap1 always be c>eful to measure f ! c5tre ( ! sp>1 z x may be set at an angle1 & ! re> ( x may be consid]ably l[] ?an its front4 ,,bor+ ,,holes ,,9 ,,wood4--,x %\ld be a /rict rule t no sp> be us$ :i* has an unnecess>y hole 9 x4 ,be=e bor+ a hole1 its position %\ld be confirm$ by :oev] is 9 *>ge ( ! work%op4 ,a bolt-hole %\ld be ( a size to enable ! bolt to be pu%$ 91 or1 at any rate1 n m ?an g5tly tapp$ 94 ,bolts %\ld n be hamm]$ 91 z t may split ! sp>4 ,on ! o!r h&1 a bolt %\ld n be slack 9 its hole1 z1 9 su* a case1 x may "w sideways & split ! sp>1 n to speak ( ?r[+ out ( adju/m5t ! wires lead+ f ! lug or socket "u ! bolt-head4 ,,wa%]s4--,"u ! bolt-head1 & also "u ! nut1 a wa%] mu/ be plac$--a v l>ge wa%] comp>$ ) ! size :i* w\ld be us$ 9 all-metal con/ruction4 ,?is is to disp]se ! /ress ov] a l>ge area2 o!rwise ! wa%] may be pull$ into ! wood & weak5 x1 besides possibly ?r[+ out ( adju/m5t ! wires atta*$ to ! bolt or ! fitt+ x is hold+ to ! sp>4 ,,lock+4--,n[ z reg>ds lock+ ! bolts4 ,if split p9s are us$1 be sure to see t !y are us$ 9 su* a way t ! nut _c possibly unscrew at all4 ,! split p9 %\ld be pass$ ?r\gh ! bolt z ne> z possible to ! nut4 ,x %\ld n be pass$ ?r\gh bo? nut & bolt4 ,if x is lock$ by burr+ ov] ! edge ( ! bolt1 d n use a heavy hamm] & try to spread ! :ole head ( ! bolt4 ,t might damage ! woodwork inside ! fabric-cov]$ surface4 ,use a small1 light hamm]1 & g5tly tap r\nd ! edge ( ! bolt until x is burr$ ov]4 ,,turnbuckles4--,a turnbuckle is compos$ ( a c5tral b>rel into ea* end ( :i* is screw$ an eye-bolt4 ,wires are tak5 f ! eyes ( ! eye-bolt1 & s1 by turn+ ! b>rel1 !y c be adju/$ to _! prop] t5sion4 ,eye-bolts mu/ be a good fit 9 ! b>rel2 t is to say1 n slack & n v tight4 ,!oretically x is n necess>y to screw ! eye-bolt into ! b>rel = a di/ance great] ?an ! diamet] ( ! bolt1 b1 9 practice1 x is bett] to screw x 9 = a consid]ably great] di/ance ?an t if a reasonable degree ( safety is to be secur$4 ,n[ ab\t turn+ ! b>rel to secure ! "r adju/m5t4 ,! b>rel looks solid1 b1 z a matt] ( fact1 x is holl[ & mu* m frail ?an x appe>s4 ,= t reason x %\ld n be turn$ by seiz+ x ) pli]s1 z t may di/ort x & spoil ! bore )9 x4 ,! be/ me?od is to pass a piece ( wire ?r\gh ! hole 9 its c5tre1 & to use t z a lev]4 ,:5 ! correct adju/m5t has be5 secur$1 ! turnbuckle mu/ be lock$ to prev5t x f unscrew+4 ,x is q possible to lock x 9 su* a way z to all[ x to unscrew a qu>t] or a half turn1 & t w\ld ?r[ ! wires out ( ! v f9e adju/m5t necess>y4 ,! prop] way is to use ! lock+ wire s t its direction is su* z to oppose ! t5d5cy ( ! b>rel to unscrew1 ?us3 ,,wires4--,! foll[+ po9ts %\ld be c>efully obs]v$ :]e wire is conc]n$3 #a4 ,quality4--,x mu/ n be too h>d or too s(t4 ,an easy practical way ( le>n+ to "k ! approximate quality ( wire is z foll[s3 ,take ?ree pieces1 all ( ! same gauge1 & ea* ab\t a foot 9 l5g?4 ,"o piece %\ld be too s(t1 ano!r too h>d1 & ! ?ird piece ( ! "r quality4 ,fix !m 9 a vice1 ab\t an in* ap>t & 9 a v]tical position1 & ) ! light f a w9d[ %9+ ^u !m4 ,burni% !m if necess>y1 & y w see a b& ( light reflect$ f ea* wire4 ,n[ b5d ! wires ov] z f> z possible & away f ! light4 ,:]e ! s(t wire is conc]n$1 x w squa% out at ! b5d1 & ?is w be indicat$ by ! b& ( light1 :i* w broad5 at t po9t4 ,9 ! case ( ! wire :i* is too h>d1 ! b& ( light w broad5 v little at ! turn1 b1 if y look c>efully1 y w see "s little r\ghnesses ( surface4 ,9 ! case ( ! wire ( ! "r quality1 ! b& ( light may broad5 a v little at ! turn1 b !re w be no r\ghnesses ( surface4 ,by mak+ ?is exp]im5t two or ?ree times "o c soon le>n to "k really bad wire f good1 & also le>n to "k ! /r5g? ( h& necess>y to b5d ! "r quality4 #b4 ,x mu/ n be damag$4 ,t is to say1 x mu/ be unk9k$1 ru/less1 & unscor$4 #c4 ,n[ z reg>ds keep+ wire 9 good condition4 ,:]e outside wires are conc]n$1 !y %\ld be kept ,,well ,,greas$ ,,or ,,oil$1 especially :]e b5t ov] at ! ends4 ,int]nal brac+ wires _c be rea*$ = ! purpose ( regreas+ !m1 z !y are inside fabric-cov]$ surfaces4 ,!y %\ld be prev5t$ f ru/+ by be+ pa9t$ ) an anti-ru/ mixture4 ,great c>e %\ld be tak5 to see t ! wire is p]fectly clean & dry be=e be+ pa9t$4 ,a greasy f+]-m>k is suffici5t to /op ! pa9t f /ick+ to ! wire4 ,9 su* a case !re w be a little space betwe5 ! pa9t & ! wire4 ,air may ent] !re & cause ! wire to ru/4 #d4 ,t5sion ( ,wires4--,! t5sion to :i* ! wires are adju/$ is ( ! greate/ importance4 ,all ! wires %\ld be ( ! same t5sion :5 ! a]oplane is support$ 9 su* a way z to ?r[ no /ress ^u !m4 ,if "s wires are 9 great] t5sion ?an o!rs1 ! a]oplane w quickly become di/ort$ & lose its effici5cy4 ,9 ord] to secure ! same t5sion ( all wires1 ! a]oplane1 :5 be+ rigg$1 %\ld be support$ by pack+ und]nea? ! l[] surfaces z well z by pack+ und]nea? ! fuselage or nacelle4 ,9 ?is way ! anti-lift wires are reliev$ ( ! weight1 & !re is no /ress ^u any ( ! wires4 ,z a g5]al rule ! wires ( an a]oplane are t5sion$ too mu*4 ,! t5sion %\ld be suffici5t to keep ! framework rigid4 ,any?+ m ?an t l[]s ! factor ( safety1 ?r[s v>i\s p>ts ( ! framework into undue compression1 pulls ! fitt+s into ! wood1 & w1 9 ! end1 di/ort ! :ole framework ( ! a]oplane4 ,only exp]i5ce w tea* ! rigg] :at t5sion to employ4 ,mu* may be done by le>n+ ! con/ruction ( ! v>i\s types ( a]oplanes1 ! "w ! v>i\s p>ts d1 & 9 cultivat+ a t\* = t5sion+ wires by con/antly h&l+ !m4 #e4 ,wires ) no ,opposition ,wires4--,9 "s few cases wires w be f\nd :i* h no opposition wires pull+ 9 ! opposite direction4 ,= in/ance1 an auxili>y lift wire may run f ! bottom ( a /rut to a sp> 9 ! top plane at a po9t betwe5 /ruts4 ,9 su* a case great c>e %\ld be tak5 n to tight5 ! wire beyond b>ely tak+ up ! slack4 ,su* a wire mu/ be a little slack1 or1 z illu/rat$ above1 x w di/ort ! framework4 ,t1 9 ! example giv51 w spoil ! camb] 7curvature7 ( ! surface1 & result 9 *ang+ bo? ! lift & ! drift at t "p ( ! surface4 ,su* a condition w cause ! a]oplane to lose its directional /ability & also to fly "o w+ d[n4 ,i _c impress ?is matt] ( t5sion ^u ! read] too /rongly4 ,x is ( ! utmo/ importance4 ,:5 ?is1 & also accuracy 9 secur+ ! v>i\s adju/m5ts1 has be5 le>n$1 "o is on ! way to becom+ a good rigg]4 #f4 ,wire ,loops4--,wire is (t5 b5t ov] at its end 9 ! =m ( a loop1 9 ord] to connect ) a turnbuckle or fitt+4 ,^! loops1 ev5 :5 made z p]fectly z possible1 h a t5d5cy to elongate1 ?us spoil+ ! adju/m5t ( ! wires ,great c>e %\ld be tak5 to m9imize ?is z f> z possible4 ,! rules to be obs]v$ are z foll[s3 7a7 ,! size ( ! loop %\ld be z small z possible )9 reason4 ,by t ,i mean x %\ld n be s small z to create ! possibility ( ! wire break+4 7b7 ,! %ape ( ! loop %\ld be symmetrical4 7c7 ,x %\ld h well-def9$ %\ld]s 9 ord] to prev5t ! f]rule f slipp+ up4 ,at ! same "t1 a %\ld] %\ld n h an angul> place4 7d7 ,:5 ! loop is f9i%$ x %\ld be undamag$1 & x %\ld n be1 z is (t5 ! case1 badly scor$4 #g4 ,/r&$ ,wire ,cable4--,no splice %\ld be s]v$ ) tw9e until x has be5 inspect$ by :oev] is 9 *>ge ( ! work%op4 ,! s]v+ may cov] bad "w4 ,%\ld a /r& become brok51 !n ! cable %\ld be replac$ at once by ano!r "o4 ,control cables h a way ( we>+ out & fray+ :]ev] !y pass r\nd pulleys4 ,e "t an a]oplane comes d[n f flight ! rigg] %\ld c>efully exam9e ! cables1 especially :]e !y pass r\nd pulleys4 ,if he f9ds a /r& brok51 he %\ld replace ! cable4 ,! ail]ons' balance cable on ! top ( ! top plane is (t5 =gott51 s9ce x is necess>y to fet* a high pair ( /eps 9 ord] to exam9e x4 ,don't slack ?is1 or "s gu/y day ! pilot may unexpect$ly f9d himself m9us ! ail]on control4 ,,controll+ ,,surfaces4--,! greate/ c>e %\ld be ex]cis$ 9 rigg+ ! ail]on1 rudd]1 & elevator prop]ly1 = ! pilot entirely dep5ds ^u !m 9 manag+ ! a]oplane4 ,! ail]ons & elevator %\ld be rigg$ s t1 :5 ! a]oplane is 9 flight1 !y are 9 a fair true l9e ) ! surface 9 front & to :i* !y are h+$4 ,if ! surface to :i* !y are h+$ is n a lift+ surface1 !n !y %\ld be rigg$ to be 9 a fair true l9e ) x z illu/rat$ above4 ,if ! controll+ surface is1 z illu/rat$1 h+$ to ! back ( a lift+ surface1 !n x %\ld be rigg$ a little bel[ ! position x w\ld occupy if 9 a fair true l9e ) ! surface 9 front4 ,?is is because1 9 su* a case1 x is set at an angle ( incid5ce4 ,?is angle w1 dur+ flight1 cause x to lift a little above ! position 9 :i* x has be5 rigg$4 ,x is able to lift ow+ to a c]ta9 am\nt ( slack 9 ! control wire hold+ x--& "o _c adju/ ! control wire to h no slack1 because t w\ld cause x to b9d aga9/ ! pulleys & make ! op]ation ( x too h>d = ! pilot4 ,x is !re=e necess>y to rig x a little bel[ ! position x w\ld occupy if x 0 rigg$ 9 a fair true l9e ) ! surface 9 front4 ,rememb] t ?is only applies :5 x is h+$ to a lift+ surface4 ,! great] ! angle ( incid5ce 7& !re=e ! lift7 ( ! surface 9 front1 !n ! m ! controll+ surface w h to be rigg$ d[n4 ,z a g5]al rule x is safe to rig x d[n s t its trail+ edge is #a_/b to #c_/d in* bel[ ! position x w\ld occupy if 9 a fair l9e ) ! surface 9 front2 or ab\t #a_/b in* d[n = e #ah in*es ( *ord ( ! controll+ surface4 ,:5 mak+ ^! adju/m5ts ! pilot's control lev]s %\ld be 9 _! neutral positions4 ,x is n suffici5t to la% !m4 ,!y %\ld be rigidly block$ into position ) wood pack+4 ,! surfaces mu/ n be di/ort$ 9 any way4 ,if !y are held true by brac+ wires1 !n su* wires mu/ be c>efully adju/$4 ,if !y are di/ort$ & !re are no brac+ wires ) :i* to true !m1 !n "s ( ! int]nal framework w probably h to be replac$4 ,! controll+ surfaces %\ld nev] be adju/$ ) a view to alt]+ ! /ability ( ! a]oplane4 ,no?+ c be accompli%$ 9 t way4 ,! only result w be to spoil ! control ( ! a]oplane4 ,,fabric-,,cov]$ ,,surfaces4--,fir/ ( all make sure t !re is no di/ortion ( sp>s or ribs1 & t !y are p]fectly s\nd4 ,!n adju/ ! int]nal brac+ wires s t ! ribs are p>allel to ! direction ( flight4 ,! ribs usually cause ! fabric to make a ridge :]e !y occur1 &1 if su* ridge is n p>allel to ! direction ( flight1 x w produce excessive drift4 ,z a rule ! ribs are at "r angles to bo? ma9 & re> sp>s4 ,! t5sion ( ! int]nal brac+ wires %\ld be j suffici5t to give rigidity to ! framework4 ,!y %\ld n be t5sion$ above t unless ! wires are1 at _! ends1 b5t to =m loops4 ,9 t case a little extra t5sion may be giv5 to (fset ! probable elongation ( ! loops4 ,! turnbuckles mu/ n[ be g5]\sly greas$1 & s]v$ r\nd ) adhesive tape4 ,! wires mu/ be r5d]$ p]fectly dry & clean1 & !n pa9t$ ) an anti-ru/ mixture4 ,! woodwork mu/ be well v>ni%$4 ,if x is necess>y to bore holes 9 ! sp>s = ! purpose ( receiv+1 = in/ance1 socket bolts1 !n _! places %\ld be m>k$ be=e be+ bor$ & _! positions confirm$ by :oev] is 9 *>ge ( ! work%op4 ,all is n[ ready = ! sail-mak] to cov] ! surface ) fabric4 ,,adju/m5t ,,( ,,control ,,cables4--,! adju/m5t ( ! control cables is q an art1 & ^u x w dep5d to a l>ge degree ! quick & easy control ( ! a]oplane by ! pilot4 ,! me?od is z foll[s3 ,aft] hav+ rigg$ ! controll+ surfaces1 & z f> z possible secur$ ! correct adju/m5t ( ! control cables1 !n remove ! pack+ :i* has kept ! control lev]s rigid4 ,!n1 sitt+ 9 ! pilot's seat1 move ! control lev]s ,,sm>tly4 ,t5sion ! control cables s t :5 ! lev]s are sm>tly mov$ !re is no p]ceptible snat* or lag4 ,be c>eful n to t5sion ! cables m ?an necess>y to take out ! snat*4 ,if t5sion$ too mu* !y w 7#a7 b9d r\nd ! pulleys & result 9 h>d "w = ! pilot2 7#b7 ?r[ dang]\s /resses ^u ! controll+ surfaces1 :i* are ( r flimsy con/ruction2 & 7#c7 cause ! cables to fray r\nd ! pulleys quick] ?an w\ld o!rwise be ! case4 ,n[1 aft] hav+ t5sion$ ! cables suffici5tly to take out ! snat*1 place ! lev]s 9 _! neutral positions1 & move !m to & fro ab\t #a_/h in* ei!r side ( su* positions4 ,if ! adju/m5t is correct1 x %\ld be possible to see ! controll+ surfaces move4 ,if !y d n move1 !n ! control cables are too slack4 ,,fly+ ,,position4--,be=e rigg+ an a]oplane or mak+ any adju/m5ts x is necess>y to place x 9 :at is kn[n z its 8fly+ position40 ,i may add t x w\ld be bett] t]m$ its 8rigg+ position40 ,9 ! case ( an a]oplane fitt$ ) a /ation>y eng9e ?is is secur$ by pack+ up ! ma*9e s t ! eng9e f\ndations are p]fectly horizontal bo? longitud9ally & lat]ally4 ,?is position is f\nd by plac+ a /raight-edge & a _s-level across ! eng9e f\ndations 7bo? longitud9ally & lat]ally71 & great c>e %\ld be tak5 to see t ! bubble is exactly 9 ! c5tre ( ! level4 ,! slighte/ error w assume magnitude t[>ds ! extremities ( ! a]oplane4 ,great c>e %\ld be tak5 to block up ! a]oplane rigidly4 ,9 case x gets accid5tally di/urb$ :ile ! "w is go+ on1 x is well to con/antly v]ify ! fly+ position by runn+ ! /raight-edge & _s-level ov] ! eng9e f\ndations4 ,! /raight-edge %\ld be c>efully te/$ be=e be+ us$1 z1 be+ g5]ally made ( wood1 x w n rema9 true long4 ,place x lightly 9 a vice1 & 9 su* a position t a _s-level on top %[s ! bubble exactly 9 ! c5tre4 ,n[ sl[ly move ! level along ! /raight-edge1 & ! bubble %\ld rema9 exactly 9 ! c5tre4 ,if x does n d s1 !n ! /raight-edge is n true & mu/ be correct$4 ,,?is ,,%\ld ,,nev] ,,be ,,omitt$4 ,9 ! case ( a]oplanes fitt$ ) eng9es ( ! rot>y type1 ! 8fly+ position0 is "s special attitude laid d[n 9 ! a]oplane's specifications1 & great c>e %\ld be tak5 to secure accuracy4 ,,angle ,,( ,,incid5ce4--,"o me?od ( f9d+ ! angle ( incid5ce is z foll[s3 ,fir/ place ! a]oplane 9 its fly+ position4 ,! corn] ( ! /raight-edge mu/ be plac$ und]nea? & aga9/ ! ,,c5tre ( ! re> sp>1 & held 9 a horizontal position p>allel to ! ribs4 ,?is is secur$ by us+ a _s-level4 ,! set measurem5t w !n be f ! top ( ! /raight-edge to ! c5tre ( ! bottom surface ( ! ma9 sp>1 or x may be f ! top ( ! /raight-edge to ! l[e/ "p ( ! lead+ edge4 ,c>e %\ld be tak5 to measure f ! c5tre ( ! sp> & to see t ! bubble is exactly 9 ! c5tre ( ! level4 ,rememb] t all ?is w be useless if ! a]oplane has n be5 plac$ accurately 9 its fly+ position4 ,?is me?od ( f9d+ ! angle ( incid5ce mu/ be us$ "u e "p ( ! l[] surface :]e /ruts occur4 ,x %\ld n be us$ betwe5 ! /ruts1 because1 9 su* places1 ! sp>s may h tak5 a slight p]man5t set up or d[n2 n1 p]haps1 suffici5tly bad to make any mat]ial diff]5ce to ! fly+ ( ! ma*9e1 b q bad en\gh to ?r[ out ! angle ( incid5ce1 :i* _c be correct$ at su* a place4 ,if ! angle is wrong1 x %\ld !n be correct$ z foll[s3 ,if x is too great1 !n ! re> sp> mu/ be w>p$ up until x is "r1 & ?is is done by slack5+ ,,all ! wires go+ to ! top ( ! /rut1 & !n tight5+ ,,all ! wires go+ to ! bottom ( ! /rut4 ,if ! angle is too small1 !n slack5 ,,all ! wires go+ to ! bottom ( ! /rut1 & tight5 ,,all ! wires go+ to ! top ( ! /rut1 until ! correct adju/m5t is secur$4 ,nev] attempt to adju/ ! angle by w>p+ ! ma9 sp>4 ,! set measurem5t1 :i* is ( c\rse /at$ 9 ! a]oplane's specifications1 %\ld be accurate to #a_/af in*4 ,,lat]al ,,dih$ral ,,angle4--,"o me?od ( secur+ ?is is z foll[s1 & ?is me?od w1 at ! same "t1 secure ! correct angle ( incid5ce3 ,! /r+s1 drawn v tight1 mu/ be tak5 ov] bo? ! ma9 & re> sp>s ( ! top surface4 ,!y mu/ run betwe5 po9ts on ! sp>s j inside ! out] /ruts4 ,! set measurem5t 7:i* %\ld be accurate to #a_/af in* or less7 is !n f ! /r+s d[n to f\r po9ts on ! ma9 & re> sp>s ( ! c5tre-section surface4 ,^! po9ts %\ld be j inside ! f\r c5tre-section /ruts2 t is to say1 z f> z possible away f ! c5tre ( ! c5tre-section4 ,d n attempt to take ! set measurem5t ne> ! c5tre ( ! c5tre-section4 ,! /r+s %\ld be z tight z possible1 &1 if x c be arrang$1 ! be/ way to accompli% t is z %[n 9 ! above illu/ration1 i4e41 by weight+ ! /r+s d[n to ! sp>s by means ( weights & ty+ ea* end ( ! /r+s to a /rut4 ,?is w give a tight & motionless /r+4 ,h[ev] c>efully ! above adju/m5t is made1 !re is sure to be "s slight error4 ,?is is ( no great importance1 provid$ x is divid$ equally betwe5 ! left- & "r-h& w+s4 ,9 ord] to make sure ( ?is1 c]ta9 *eck measurem5ts %\ld be tak5 z foll[s3 ,ea* bay mu/ be diagonally measur$1 & su* measurem5ts mu/ be ! same to )9 #a_/af in* on ea* side ( ! a]oplane4 ,z a rule su* diagonal measurem5ts are tak5 f ! bottom socket ( "o /rut to ! top socket ( ano!r /rut1 b ?is is bad practice1 because ( possible inaccuracies due to faulty manufacture4 ,! po9ts betwe5 :i* ! diagonal measurem5ts are tak5 %\ld be at fix$ di/ances f ! butts ( ! sp>s1 su* di/ances be+ ! same on ea* side ( ! a]oplane1 ?us3 ,x w\ld be bett] to use ! c5tre l9e ( ! a]oplane r ?an ! butts ( ! sp>s4 ,x is n practicable to d s1 h[ev]1 z ! c5tre l9e probably runs ?r\gh ! petrol tanks1 etc4 ,,! ,,dih$ral ,,bo>d4--,ano!r me?od ( secur+ ! dih$ral angle1 & also ! angle ( incid5ce1 is by means ( ! dih$ral bo>d4 ,x is a light h&y ?+ to use1 b leads to _m errors1 & %\ld n be us$ unless necess>y4 ,! reasons are z foll[s3 ,! dih$ral bo>d is probably n true4 ,if x mu/ be us$1 !n x %\ld be v c>efully te/$ = tru? be=e-h&4 ,ano!r reason aga9/ its use is t x has to be plac$ on ! sp>s 9 a position betwe5 ! /ruts1 & t is j :]e ! sp>s may h a little p]man5t set up or d[n1 or "s inaccuracy ( surface :i* w1 ( c\rse1 ?r[ out ! accuracy ( ! adju/m5t4 ,! me?od ( us+ x is z foll[s3 ,! bo>d is cut to ! same angle z t specifi$ = ! upw>d incl9ation ( ! surface t[>ds its w+-tips4 ,x is plac$ on ! sp> z indicat$ above1 & x is provid$ ) two %ort legs to raise x above ! flanges ( ! ribs 7:i* cross ov] ! sp>s71 z !y may v>y 9 dep?4 ,a _s-level is !n plac$ on ! bo>d1 & ! wires mu/ be adju/$ to give ! surface su* an incl9ation z to result 9 ! bubble be+ 9 ! c5tre ( ! level4 ,?is op]ation mu/ be p]=m$ 9 respect ( ea* bay bo? front & re>4 ,! bays mu/ !n be diagonally measur$ z already expla9$4 ,,yet ,,ano!r ,,me?od ( f9d+ ! dih$ral angle1 & at ! same "t ! angle ( incid5ce1 is z foll[s3 ,a horizontal l9e is tak5 f und]nea? ! butt ( ea* sp>1 & ! set measurem5t is ei!r ! angle x makes ) ! sp>1 or a fix$ measurem5t f ! l9e to ! sp> tak5 at a specifi$ di/ance f ! butt4 ,?is op]ation mu/ be p]=m$ 9 respect ( bo? ma9 & re> sp>s1 & all ! bays mu/ be measur$ diagonally aft]w>ds4 ,:i*ev] me?od is us$1 be sure t aft] ! job is done ! sp>s are p]fectly /raight4 ,,/agg]4--,! /agg] is ! di/ance ! top surface is 9 advance ( ! bottom surface :5 ! a]oplane is 9 fly+ position4 ,! set measurem5t is obta9$ z foll[s3 ,plumb-l9es mu/ be dropp$ ov] ! lead+ edge ( ! top surface :]ev] /ruts occur1 & also ne> ! fuselage4 ,! set measurem5t is tak5 f ! front ( ! l[] lead+ edge to ! plumb-l9es4 ,x makes a diff]5ce :e!r ! measurem5t is tak5 along a horizontal l9e 7:i* c be f\nd by us+ a /raight-edge & a _s-level7 or along a projection ( ! *ord4 ,! l9e along :i* ! measurem5t %\ld be tak5 is laid d[n 9 ! a]oplane's specifications4 ,if a mi/ake is made & ! measurem5t tak5 along ! wrong l9e1 x may result 9 a diff]5ce ( p]haps #a_/d w1 9 flight1 be nose-heavy or tail-heavy4 ,aft] ! adju/m5ts ( ! angles ( incid5ce1 dih$ral1 & /agg] h be5 secur$1 x is z well to confirm all ( !m1 z1 9 mak+ ! la/ adju/m5t1 ! fir/ "o may h be5 spoil$4 ,,ov]-,,all ,,adju/m5ts4--,! foll[+ ov]-all *eck measurem5ts %\ld n[ be tak54 ,! /raight l9es ,,ac & ,,bc %\ld be equal to )9 #a_/h in*4 ,! po9t ,c is ! c5tre ( ! propell]1 or1 9 ! case ( a 8pu%]0 a]oplane1 ! c5tre ( ! nacelle4 ,! po9ts ,a & ,b are m>k$ on ! ma9 sp>1 & mu/ 9 ea* case be ! same di/ance f ! butt ( ! sp>4 ,! rigg] %\ld n attempt to make ,a & ,b m]ely ! sockets ( ! out] /ruts1 z !y may n h be5 plac$ q accurately by ! manufactur]4 ,! l9es ,,ac & ,,bc mu/ be tak5 f bo? top & bottom sp>s--two measurem5ts on ea* side ( ! a]oplane4 ,! two measurem5ts ,,fd & ,,fe %\ld be equal to )9 #a_/h in*4 ,f is ! c5tre ( ! fuselage or rudd]-po/4 ,d & ,e are po9ts m>k$ on bo? top & bottom re> sp>s1 & ea* mu/ be ! same fix$ di/ance f ! butt ( ! sp>4 ,two measurem5ts on ea* side ( ! a]oplane4 ,if ^! ov]-all measurem5ts are n correct1 !n x is probably due to "s ( ! drift or anti-drift wires be+ too tight or too slack4 ,x may possibly be due to ! fuselage be+ out ( tru?1 b ( c\rse ! rigg] %\ld h made q sure t ! fuselage 0 true be=e rigg+ ! re/ ( ! ma*9e4 ,aga91 x may be due to ! int]nal brac+ wires )9 ! lift+ surfaces n be+ accurately adju/$1 b ( c\rse ?is %\ld h be5 se5 to be=e cov]+ ! surfaces ) fabric4 ,,fuselage4--,! me?od ( tru+ ! fuselage is laid d[n 9 ! a]oplane's specifications4 ,aft] x has be5 adju/$ accord+ to ! specifi$ directions1 x %\ld !n be arrang$ on tre/les 9 su* a way z to make ab\t ?ree-qu>t]s ( x t[>ds ! tail /ick out unsupport$4 ,9 ?is way x w assume a condition z ne> z possible to fly+ conditions1 & :5 x is 9 ?is position ! set measurem5ts %\ld be confirm$4 ,if ?is is n done x may be out ( tru?1 b p]haps appe> all "r :5 support$ by tre/les at bo? ends1 z1 9 su* case1 its weight may keep x true z long z x is re/+ ^u ! tre/les4 ,,! ,,tail-,,plane 7,,emp5nage74--,! exact angle ( incid5ce ( ! tail-plane is laid d[n 9 ! a]oplane's specifications4 ,x is necess>y to make sure t ! sp>s are horizontal :5 ! a]oplane is 9 fly+ position & ! tail unsupport$ z expla9$ above "u ! head+ ( ,fuselage4 ,if ! sp>s are tap]$1 !n make sure t _! c5tre l9es are horizontal4 ,,und]c>riage4--,! und]c>riage mu/ be v c>efully align$ z laid d[n 9 ! specifications4 #a4 ,! a]oplane mu/ be plac$ 9 its fly+ position & suffici5tly high to ensure ! :eels be+ (f ! gr\nd :5 rigg$4 ,:5 9 ?is position ! axle mu/ be horizontal & ! brac+ wires adju/$ to secure ! v>i\s set measurem5ts /at$ 9 ! specifications4 #b4 ,make sure t ! /ruts b$ well d[n into _! sockets4 #c4 ,make sure t ! %ock absorb]s are ( equal t5sion4 ,9 ! case ( rubb] %ock absorb]s1 bo? ! numb] ( turns & ! l5g?s mu/ be equal4 ,,h[ ,,to ,,diagnose ,,faults ,,9 ,,flight1 ,,/ability1 ,,& ,,control4 ,,directional ,,/ability w be badly affect$ if !re is m drift 7i4e41 resi/ance7 on "o side ( ! a]oplane ?an !re is on ! o!r side4 ,! a]oplane w t5d to turn t[>ds ! side hav+ ! mo/ drift4 ,?is may be caus$ z foll[s3 #a4 ,! angle ( incid5ce ( ! ma9 surface or ! tail surface may be wrong4 ,! great] ! angle ( incid5ce1 ! great] ! drift4 ,! less ! angle1 ! less ! drift4 #b4 ,if ! alignm5t ( ! fuselage1 f9 9 front ( ! rudd]1 ! /ruts or /ream-l9e wires1 or1 9 ! case ( ! ,maurice ,f>man1 ! front outrigg]s1 are n absolutely correct--t is to say1 if !y are turn$ a little to ! left or to ! "r in/ead ( be+ 9 l9e ) ! direction ( flight--!n !y w act z a rudd] & cause ! a]oplane to turn (f its c\rse4 #c4 ,if any "p ( ! surface is di/ort$1 x w cause ! a]oplane to turn (f its c\rse4 ,! surface is camb]$1 i4e41 curv$1 to pass ?r\gh ! air ) ! lea/ possible drift4 ,if1 ow+ p]haps to ! lead+ edge1 sp>s1 or trail+ edge becom+ b5t1 ! curvature is spoil$1 t w result 9 *ang+ ! am\nt ( drift on "o side ( ! a]oplane1 :i* w !n h a t5d5cy to turn (f its c\rse4 ,,lat]al ,,in/ability 7,,fly+ ,,"o ,,w+ ,,d[n74--,! only possible reason = su* a condition is a diff]5ce 9 ! lifts ( "r & left w+s4 ,t may be caus$ z foll[s3 #a4 ,! angle ( incid5ce may be wrong4 ,if x is too great1 x w produce m lift ?an on ! o!r side ( ! a]oplane2 & if too small1 x w produce less lift ?an on ! o!r side--! result be+ t1 9 ei!r case1 ! a]oplane w try to fly "o w+ d[n4 #b4 ,di/ort$ ,surfaces4--,if "s "p ( ! surface is di/ort$1 !n its camb] is spoil$1 & ! lift w n be ! same on bo? sides ( ! a]oplane1 & t1 ( c\rse1 w cause x to fly "o w+ d[n4 ,,longitud9al ,,in/ability may be due to ! foll[+ reasons3 #a4 ,! /agg] may be wrong4 ,! top surface may h drift$ back a little ow+ to "s ( ! wires1 probably ! incid5ce wires1 hav+ elongat$ _! loops or hav+ pull$ ! fitt+s into ! wood4 ,if ! top surface is n /agg]$ =w>d to ! correct degree1 !n consequ5tly ! :ole ( its lift is too f> back1 & x w !n h a t5d5cy to lift up ! tail ( ! ma*9e too mu*4 ,! a]oplane w\ld !n be said to be 8nose-heavy40 ,a #a_/d-;in* area 9 ! /agg] w make a v consid]able diff]5ce to ! longitud9al /ability4 #b4 ,if ! angle ( incid5ce ( ! ma9 surface is n "r1 x w h a bad effect1 especially 9 ! case ( an a]oplane ) a lift+ tail-plane4 ,if ! angle is too great1 x w produce an excess ( lift1 & t may lift up ! nose ( ! a]oplane & result 9 a t5d5cy to fly 8tail-d[n40 ,if ! angle is too small1 x w produce a decreas$ lift1 & ! a]oplane may h a t5d5cy to fly 8nose-d[n40 #c4 ,! fuselage may h become w>p$ upw>d or d[nw>d1 ?us giv+ ! tail-plane an incorrect angle ( incid5ce4 ,if x has too mu* angle1 x w lift too mu*1 & ! a]oplane w be 8nose-heavy40 ,if x has too little angle1 !n x w n lift en\gh1 & ! a]oplane w be 8tail-heavy40 #d4 7,! lea/ likely reason47 ,! tail-plane may be m\nt$ ^u ! fuselage at a wrong angle ( incid5ce1 9 :i* case x mu/ be correct$4 ,if nose-heavy1 x %\ld be giv5 a small] angle ( incid5ce4 ,if tail-heavy1 x %\ld be giv5 a l>g] angle2 b c>e %\ld be tak5 n to give x too great an angle1 because ! longitud9al /ability entirely dep5ds ^u ! tail-plane be+ set at a mu* small] angle ( incid5ce ?an is ! ma9 surface1 & if t diff]5ce is decreas$ too mu*1 ! a]oplane w become uncontrollable longitud9ally4 ,sometimes ! tail-plane is m\nt$ on ! a]oplane at ! same angle z ! ma9 surface1 b x actually engages ! air at a less] angle1 ow+ to ! air be+ deflect$ d[nw>ds by ! ma9 surface4 ,!re is !n1 9 effect1 a longitud9al dih$ral z expla9$ & illu/rat$ 9 ,*apt] ,i4 ,,climbs ,,badly4--,su* a condition is1 ap>t f eng9e or propell] tr\ble1 probably due to 7#a7 di/ort$ surfaces1 or 7#b7 too small an angle ( incid5ce4 ,,flight ,,spe$ ,,poor4--,su* a condition is1 ap>t f eng9e or propell] tr\ble1 probably due to 7#a7 di/ort$ surfaces1 7#b7 too great an angle ( incid5ce1 or 7#c7 dirt or mud1 & consequ5tly excessive sk9-friction4 ,,ineffici5t ,,control is probably due to 7#a7 wrong sett+ ( control surfaces1 7#b7 di/ortion ( control surfaces1 or 7#c7 control cables be+ badly t5sion$4 ,,w ,,n ,,taxi ,,/raight4--,if ! a]oplane is uncontrollable on ! gr\nd1 x is probably due to 7#a7 alignm5t ( und]c>riage be+ wrong1 or 7#b7 unequal t5sion ( %ock absorb]s4 ,,*apt] ,,iv4 ,,! ,,propell]1 ,,or 8,,air-,,screw0 ,! sole object ( ! propell] is to translate ! p[] ( ! eng9e into ?ru/4 ,! propell] screws ?r\gh ! air1 & its blades1 be+ set at an angle incl9$ to ! direction ( motion1 secure a reaction1 z 9 ! case ( ! a]oplane's lift+ surface4 ,?is reaction may be conv5i5tly divid$ into two compon5t p>ts or values1 namely1 ,?ru/ & ,drift4 ,! ,?ru/ is oppos$ to ! ,drift ( ! a]oplane1 & mu/ be equal & opposite to x at fly+ spe$4 ,if x falls (f 9 p[]1 !n ! fly+ spe$ mu/ decrease to a velocity1 at :i* ! a]oplane drift equals ! decreas$ ?ru/4 ,! ,drift ( ! propell] may be conv5i5tly divid$ into ! foll[+ compon5t values3 ,active ,drift1 produc$ by ! useful ?ru/+ "p ( ! propell]4 ,passive ,drift1 produc$ by all ! re/ ( ! propell]1 i4e41 by its detrim5tal surface4 ,sk9 ,friction1 produc$ by ! friction ( ! air ) r\ghnesses ( surface4 ,eddies att5d+ ! movem5t ( ! air caus$ by ! action ( ! propell]4 ,cavitation 7v m>k$ at excessive spe$ ( revolution74 ,a t5d5cy ( ! propell] to produce a cavity or semi-vacuum 9 :i* x revolves1 ! ?ru/ decreas+ ) increase ( spe$ & cavitation4 ,,?ru/-,,drift ,,ratio4--,! proportion ( ?ru/ to drift is ( p>am\nt importance1 = x expresses ! effici5cy ( ! propell]4 ,x is affect$ by ! foll[+ factors3 ,spe$ ( ,revolution4--,! great] ! spe$1 ! great] ! proportion ( drift to ?ru/4 ,?is is due to ! increase ) spe$ ( ! passive drift1 :i* c>ries ) x no increase 9 ?ru/4 ,= ?is reason propell]s are (t5 ge>$ d[n to revolve at a l[] spe$ ?an t ( ! eng9e4 ,angle ( ,incid5ce4--,! same reasons z 9 ! case ( ! a]oplane surface4 ,surface ,area4--,ditto4 ,aspect ,ratio4--,ditto4 ,camb]4--,ditto4 ,9 addition to ! above factors !re are1 :5 x comes to actually design+ a propell]1 me*anical difficulties to consid]4 ,= in/ance1 ! blades mu/ be ( a c]ta9 /r5g? & consequ5t ?ickness4 ,t1 9 itself1 limits ! aspect ratio1 = x w necessitate a *ord long en\gh 9 proportion to ! ?ickness to make a good camb] possible4 ,aga91 ! diamet] ( ! propell] mu/ be limit$1 hav+ reg>d to ! fact t great] diamet]s ?an ^? us$ to-day w\ld n only result 9 excessive weight ( con/ruction1 b w\ld also necessitate a v high und]c>riage to keep ! propell] (f ! gr\nd1 & su* und]c>riage w\ld n only produce excessive drift1 b w\ld also t5d to make ! a]oplane /& on its nose :5 alight+4 ,! latt] difficulty _c be ov]come by m\nt+ ! propell] high]1 z ! c5tre ( its ?ru/ mu/ be approximately co9cid5t ) ! c5tre ( a]oplane drift4 ,,ma9t5ance ,,( ,,effici5cy4 ,! foll[+ conditions mu/ be obs]v$3 #a4 ,,pit* ,,angle4--,! angle1 at any giv5 po9t on ! propell]1 at :i* ! blade is set is kn[n z ! pit* angle1 & x mu/ be correct to half a degree if reasonable effici5cy is to be ma9ta9$4 ,?is angle secures ! 8pit*10 :i* is ! di/ance ! propell] advances dur+ "o revolution1 suppos+ ! air to be solid4 ,! air1 z a matt] ( fact1 gives back to ! ?ru/ ( ! blades j z ! pebbles slip back z "o asc5ds a %+le bea*4 ,su* 8give-back0 is kn[n z ,slip4 ,if a propell] has a pit* (1 say1 #aj feet1 b actually advances1 say1 only #h feet ow+ to slip1 !n x w be said to possess #bj p] c5t4 slip4 ,?us1 ! pit* mu/ equal ! fly+ spe$ ( ! a]oplane plus ! slip ( ! propell]4 ,= example1 let u f9d ! pit* ( a propell]1 giv5 ! foll[+ conditions3 ,fly+ spe$44444444444444 #gj miles p] h\r4 ,propell] revolutions44444 #a1bjj p] m9ute4 ,slip4444444444444444444444 #ae p] c5t4 ,fir/ f9d ! di/ance 9 feet ! a]oplane w travel =w>d 9 "o m9ute4 ,t is-- #cfi1fjj feet 7#gj miles7 ------------------------ #f1afj feet p] m9ute4 #fj 8 7m9utes7 ,n[ divide ! feet p] m9ute by ! propell] revolutions p] m9ute1 add #ae p] c5t4 = ! slip1 & ! result w be ! propell] pit*3 #f1afj ----- #ae p] c5t4 #e feet #a #c_/e in*es4 #a1bjj ,9 ord] to secure a con/ant pit* f root to tip ( blade1 ! pit* angle decreases t[>ds ! tip4 ,?is is necess>y1 s9ce ! end ( ! blade travels fa/] ?an its root1 & yet mu/ advance =w>d at ! same spe$ z ! re/ ( ! propell]4 ,= example1 two m5 asc5d+ a hill4 ,"o pref]s to walk fa/ & ! o!r sl[ly1 b !y wi% to arrive at ! top ( ! hill simultane\sly4 ,!n ! fa/ walk] mu/ travel a f>!r di/ance ?an ! sl[ "o1 & 8 angle ( pa? 7pit* angle7 mu/ be small] ?an ! angle ( pa? tak5 by ! sl[ walk]4 ,_! pit* angles are diff]5t1 b _! pit* 79 ?is case altitude rea*$ 9 a giv5 "t7 is ! same4 ,9 ord] to te/ ! pit* angle1 ! propell] mu/ be m\nt$ ^u a %aft at "r angles to a beam ! face ( :i* mu/ be p]fectly level1 ?us3 ,fir/ select a po9t on ! blade at "s di/ance 7say ab\t #b feet7 f ! c5tre ( ! propell]4 ,at t po9t f9d1 by means ( a protractor1 ! angle a projection ( ! *ord makes ) ! face ( ! beam4 ,t angle is ! pit* angle ( ! blade at t po9t4 ,n[ lay out ! angle on pap]1 ?us3 ,! l9e above & p>allel to ! circumf]5ce l9e mu/ be plac$ 9 a position mak+ ! di/ance betwe5 ! two l9es equal to ! specifi$ pit*1 :i* is1 or %\ld be1 m>k$ ^u ! boss ( ! propell]4 ,n[ f9d ! circumf]5ce ( ! propell] :]e ! pit* angle is be+ te/$4 ,= example1 if t place is #b feet radius f ! c5tre1 !n ! circumf]5ce w be #b feet ,x #b #d feet diamet]1 :i*1 if multipli$ by #c4adaf #ae4ef feet circumf]5ce4 ,n[ m>k (f ! circumf]5ce di/ance1 :i* is repres5t$ above by ,a-,b1 & r$uce x 9 scale = conv5i5ce4 ,! di/ance a v]tical l9e makes betwe5 ,b & ! *ord d9e is ! pit* at ! po9t :]e ! angle is be+ te/$1 & x %\ld co9cide ) ! specifi$ pit*4 ,y w note1 f ! above illu/ration1 t ! actual pit* l9e %\ld meet ! junction ( ! *ord l9e & top l9e4 ,! propell] %\ld be te/$ at sev]al po9ts1 ab\t a foot ap>t1 on ea* blade2 & ! diagram1 provid$ ! propell] is n faulty1 w !n look l ?is3 ,at ea* po9t te/$ ! actual pit* co9cides ) ! specifi$ pit*3 a satisfactory condition4 ,a faulty propell] w produce a diagram some?+ l ?is3 ,at e po9t te/$ ! pit* angle is wrong1 = n[h]e does ! actual pit* co9cide ) ! specifi$ pit*4 ,angles ,a1 ,c1 & ,d1 are too l>ge1 & ,b is too small4 ,! angle %\ld be correct to half a degree if reasonable effici5cy is to be ma9ta9$4 ,a fault 9 ! pit* angle may be due to 7#a7 faulty manufacture1 7#b7 di/ortion1 or 7#c7 ! %aft hole ?r\gh ! boss be+ out ( position4 #b4 ,,/raightness4--,to te/ = /raightness ! propell] mu/ be m\nt$ ^u a %aft4 ,n[ br+ ! tip ( "o blade r\nd to graze "s fix$ object4 ,m>k ! po9t x grazes4 ,n[ br+ ! o!r tip r\nd1 & x %\ld come )9 #a_/h in* ( ! m>k4 ,if x does n d s1 x is due to 7#a7 faulty manufacture1 7#b7 di/ortion1 or 7#c7 to ! hole ?r\gh ! boss be+ out ( position4 #c4 ,,l5g?4--,! blades %\ld be ( equal l5g? to in*4 #d4 ,,balance4--,! usual me?od ( te/+ a propell] = balance is z foll[s3 ,m\nt x ^u a %aft1 :i* mu/ be on ball-be>+s4 ,place ! propell] 9 a horizontal position1 & x %\ld rema9 9 t position4 ,if a weight ( a trifle ov] an ounce plac$ 9 a bolt-hole on "o side ( ! boss fails to di/urb ! balance1 !n ! propell] is usually reg>d$ z unfit = use4 ,! above me?od is r futile1 z x does n te/ = ! balance ( c5trifugal =ce1 :i* comes into play z soon z ! propell] revolves4 ,x c be te/$ z foll[s3 ,! propell] mu/ be 9 a horizontal position1 & !n weigh$ at fix$ po9ts1 su* z ,a1 ,b1 ,c1 ,d1 ,e1 & ,f1 & ! weights not$4 ,! po9ts ,a1 ,b1 & ,c mu/1 ( c\rse1 be at ! same fix$ di/ances f ! c5tre ( ! propell] z ! po9ts ,d1 ,e1 & ,f4 ,n[ rev]se ! propell] & weigh at ea* po9t aga94 ,note ! results4 ,! fir/ s]ies ( weights %\ld correspond to ! second s]ies1 ?us3 ,weight ,a %\ld equal weight ,f4 8 ,b 8 8 8 ,e4 8 ,c 8 8 8 ,d4 ,!re is no /&>d practice z to ! degree ( error p]missible1 b if !re are any appreciable diff]5ces ! propell] is unfit = use4 #e4 ,,surface ,,area4--,! surface area ( ! blades %\ld be equal4 ,te/ ) callip]s ?us3 ,! po9ts betwe5 :i* ! di/ances are tak5 mu/1 ( c\rse1 be at ! same di/ance f ! c5tre 9 ! case ( ea* blade4 ,!re is no /&>d practice z to ! degree ( error p]missible4 ,if1 h[ev]1 !re is an error ( ov] #a_/h in*1 ! propell] is really unfit = use4 #f4 ,,camb]4--,! camb] 7curvature7 ( ! blades %\ld be 7#a7 equal1 7#b7 decrease ev5ly t[>ds ! tips ( ! blades1 & 7#c7 ! greate/ dep? ( ! curve %\ld1 at any po9t ( ! blade1 be approximately at ! same p]c5tage ( ! *ord f ! lead+ edge z at o!r po9ts4 ,x is difficult to te/ ! top camb] )\t a set ( templates1 b a fairly accurate idea ( ! concave camb] c be secur$ by sl[ly pass+ a /raight-edge along ! blade1 ?us3 ,! camb] c n[ be easily se51 & z ! /raight-edge is pass$ along ! blade1 ! obs]v] %\ld look = any irregul>ities ( ! curvature1 :i* %\ld gradually & ev5ly decrease t[>ds ! tip ( ! blade4 #g4 ,,! ,,jo9ts4--,! usual me?od = te/+ ! glu$ jo9ts is by revolv+ ! propell] at great] spe$ ?an x w be call$ ^u to make dur+ flight1 & !n c>efully exam9+ ! jo9ts to see if !y h op5$4 ,x is n likely1 h[ev]1 t ! read] w h ! opportunity ( mak+ ?is te/4 ,he %\ld1 h[ev]1 exam9e all ! jo9ts v c>efully1 try+ by h& to see if !y are q s\nd4 ,suspect a propell] ( :i* ! jo9ts appe> to hold any ?ickness ( glue4 ,sometimes ! jo9ts 9 ! boss op5 a little1 b ?is is n dang]\s unless !y ext5d to ! blades1 z ! bolts w hold ! lam9ations toge!r4 #h4 ,,condition ,,( ,,surface4--,! surface %\ld be v smoo?1 especially t[>ds ! tips ( ! blades4 ,"s propell] tips h a spe$ ( ov] #cj1jjj feet a m9ute1 & any r\ghness w produce a bad drift or resi/ance & l[] ! effici5cy4 #i4 ,,m\nt+4--,great c>e %\ld be tak5 to see t ! propell] is m\nt$ q /raight on its %aft4 ,te/ 9 ! same way z = /raightness4 ,if x is n /raight1 x is possibly due to "s ( ! propell] bolts be+ too slack or to o!rs hav+ be5 pull$ up too tightly4 ,,flutt]4--,propell] 8flutt]10 or vibration1 may be due to faulty pit* angle1 balance1 camb]1 or surface area4 ,x causes a condition sometimes mi/ak5 = eng9e tr\ble1 & "o :i* may easily lead to ! collapse ( ! propell]4 ,,c>e ,,( ,,propell]s4--,! c>e ( propell]s is ( ! greate/ importance1 z !y become di/ort$ v easily4 #a4 ,d n /ore !m 9 a v damp or a v dry place4 #b4 ,d n /ore !m :]e ! sun w %9e ^u !m4 #c4 ,nev] leave !m long 9 a horizontal position or lean+ up aga9/ a wall4 #d4 ,!y %\ld be hung on horizontal pegs1 & ! position ( ! propell]s %\ld be v]tical4 ,if ! po9ts ,i h impress$ ^u y 9 ^! notes are n att5d$ to1 y may be sure ( ! foll[+ results3 #a4 ,lack ( effici5cy1 result+ 9 less a]oplane spe$ & climb ?an w\ld o!rwise be ! case4 #b4 ,propell] 8flutt]0 & possible collapse4 #c4 ,a bad /ress ^u ! propell] %aft & its be>+s4 ,,tractor4--,a propell] m\nt$ 9 front ( ! ma9 surface4 ,,pu%]4--,a propell] m\nt$ beh9d ! ma9 surface4 ,,f\r-,,blad$ ,,propell]s4--,f\r-blad$ propell]s are suitable only :5 ! pit* is comp>atively l>ge4 ,= a giv5 pit*1 & hav+ reg>d to 8int]f]5ce10 !y are n s effici5t z two-blad$ propell]s4 ,! small] ! pit*1 ! less ! 8gap10 i4e41 ! di/ance1 measur$ 9 ! direction ( ! ?ru/1 betwe5 ! spiral c\rses ( ! blades4 ,if ! gap is too small1 !n ! foll[+ blade w engage air :i* ! prec$+ blade has put into motion1 ) ! result t ! foll[+ blade w n secure z good a reaction z w\ld o!rwise be ! case4 ,x is v mu* ! same z 9 ! case ( ! a]oplane gap4 ,= a giv5 pit*1 ! gap ( a f\r-blad$ propell] is only half t ( a two-blad$ "o4 ,!re=e ! f\r-blad$ propell] is only suitable = l>ge pit*1 z su* pit* produces spirals ) a l>ge gap1 ?us (fsett+ ! decrease 9 gap caus$ by ! num]\s blades4 ,! great] ! spe$ ( rotation1 ! less ! pit* = a giv5 a]oplane spe$4 ,!n1 9 ord] to secure a l>ge pit* & consequ5tly a good gap1 ! f\r-blad$ propell] is usually ge>$ to rotate at a l[] spe$ ?an w\ld be ! case if directly atta*$ to ! eng9e crank-%aft4 ,,*apt] ,v4 ,,ma9t5ance ,,cleanl9ess4--,! fabric mu/ be kept clean & free f oil1 z t w rot x4 ,to take out dirt or oily pat*es1 try acetone4 ,if t w n rem$y matt]s1 !n try petrol1 b use x sp>+ly1 z o!rwise x w take (f an unnecess>y am\nt ( dope4 ,if t w n remove ! dirt1 !n hot wat] & soap w d s1 b1 9 t case1 be sure to use soap hav+ no alkali 9 x1 z o!rwise x may injure ! fabric4 ,use ! wat] sp>+ly1 or x may get inside ! planes & ru/ ! int]nal brac+ wires1 or cause "s ( ! wood5 framework to swell4 ,! :eels ( ! und]c>riage h a way ( ?r[+ up mud on to ! l[] surface4 ,?is %\ld1 if possible1 be tak5 (f :ile wet4 ,x %\ld nev] be scrap$ (f :5 dry1 z t may injure ! fabric4 ,if dry1 !n x %\ld be moi/5$ be=e be+ remov$4 ,measures %\ld be tak5 to prev5t dirt f collect+ ^u any "p ( ! a]oplane1 z1 o!rwise1 excessive sk9-friction w be produc$ ) resultant loss ( flight spe$4 ,! wires1 be+ greasy1 collect dirt v easily4 ,,control ,,cables4--,aft] e flight ! rigg] %\ld pass 8 h& ov] ! control cables & c>efully exam9e !m ne> pulleys4 ,removal ( grease may be necess>y to make a close inspection possible4 ,if only "o /r& is brok5 ! wire %\ld be replac$4 ,d n =get ! ail]on balance wire on ! top surface4 ,once a day try ! t5sion ( ! control cables by sm>tly mov+ ! control lev]s ab\t z expla9$ else:]e4 ,,wires4--,all ! wires %\ld be kept well greas$ or oil$1 & 9 ! correct t5sion4 ,:5 exam9+ ! wires1 x is necess>y to place ! a]oplane on level gr\nd1 z o!rwise x may be twi/$1 ?us ?r[+ "s wires into undue t5sion & slack5+ o!rs4 ,! be/ way1 if !re is "t1 is to pack ! ma*9e up into its 8fly+ position40 ,if y see a slack wire1 d n jump to ! conclusion t x mu/ be t5sion$4 ,p]haps its opposition wire is too tight1 9 :i* case slack5 x1 & possibly y w f9d t w tight5 ! slack wire4 ,c>efully exam9e all wires & _! connections ne> ! propell]1 & be sure t !y are snak$ r\nd ) safety wire1 s t ! latt] may keep !m out ( ! way ( ! propell] if !y come adrift4 ,! wires inside ! fuselage %\ld be clean$ & regreas$ ab\t once a =tnight4 ,,/ruts ,,& ,,sockets4--,^! %\ld be c>efully exam9$ to see if any splitt+ has occurr$4 ,,di/ortion4--,c>efully exam9e all surfaces1 includ+ ! controll+ surfaces1 to see :e!r any di/ortion has occurr$4 ,if di/ortion c be correct$ by ! adju/m5t ( wires1 well & good2 b if n1 !n "s ( ! int]nal framework probably requires replacem5t4 ,,adju/m5ts4--,v]ify ! angles ( incid5ce2 dih$ral1 & /agg]1 & ! rigg+ position ( ! controll+-surfaces1 z (t5 z possible4 ,,und]c>riage4--,con/antly exam9e ! alignm5t & fitt+s ( ! und]c>riage1 & ! condition ( tyres & %ock absorb]s4 ,! latt]1 :5 made ( rubb]1 we> quicke/ und]nea?4 ,inspect axles & skids to see if !re are any signs ( !m becom+ b5t4 ,! :eels %\ld be tak5 (f occasionally & greas$4 ,,lock+ ,,arrangem5ts4--,con/antly inspect ! lock+ arrangem5ts ( turnbuckles1 bolts1 etc4 ,pay p>ticul> att5tion to ! control cable connections1 & to all mov+ p>ts 9 respect ( ! controls4 ,,lubrication4--,keep all mov+ p>ts1 su* z pulleys1 control lev]s1 & h+es ( controll+ surfaces1 well greas$4 ,,special ,,inspection4--,ap>t f con/antly exam9+ ! a]oplane ) ref]5ce to ! above po9ts ,i h made1 ,i ?9k t1 9 ! case ( an a]oplane 9 con/ant use x is an excell5t ?+ to make a special inspection ( e "p1 say once a week4 ,?is w take f two to ?ree h\rs1 accord+ to ! type ( a]oplane4 ,9 ord] to c>ry x out me?odically1 ! rigg] %\ld h a li/ ( e "p d[n to ! smalle/ split-p94 ,he c !n *eck ! p>ts z he exam9es !m1 & no?+ w be pass$ ov]4 ,?is1 ,i "k f exp]i5ce1 greatly increases ! confid5ce ( ! pilot1 & t5ds to produce good "w 9 ! air4 ,,w9dy ,,wea!r4--,! a]oplane1 :5 on ! gr\nd1 %\ld face ! w9d2 & x is advisable to la% ! control lev] fa/1 s t ! controll+ surfaces may n be bl[n ab\t & possibly damag$4 8,,vett+0 ,,by ,,eye4--,?is %\ld be practic$ at e opportunity1 &1 if p]sev]$ 91 x is possible to become q exp]t 9 diagnos+ by eye faults 9 flight effici5cy1 /ability & control4 ,! a]oplane %\ld be /&+ ^u level gr\nd1 or1 bett] ?an t1 pack$ up into its 8fly+ position40 ,n[ /& 9 front ( x & l9e up ! lead+ edge ) ! ma9 sp>1 re> sp>1 & trail+ edge4 ,_! %ad[s c usually be se5 ?r\gh ! fabric4 ,all[ance mu/1 ( c\rse1 be made = wa%-9 & wa%-out2 o!rwise1 ! p>ts ,i h specifi$ %\ld be p>allel ) ea* o!r4 ,n[ l9e up ! c5tre "p ( ! ma9-plane ) ! tail-plane4 ,! latt] %\ld be horizontal4 ,next1 sight ea* int]plane front /rut ) its re> /rut4 ,!y %\ld be p>allel4 ,!n1 /&+ on "o side ( ! a]oplane1 sight all ! front /ruts4 ,! "o ne>e/ to y %\ld cov] all ! o!rs4 ,?is applies to ! re> /ruts also4 ,look = di/ortion ( lead+ edges1 ma9 & re> sp>s1 trail+ edges1 tail-plane & controll+ surfaces4 ,?is sort ( ?+1 if practic$ con/antly1 w n only develop an exp]t eye = diagnosis ( faults1 b w also greatly assi/ 9 impress+ ^u ! memory ! *>act]i/ics & possible tr\bles ( ! v>i\s types ( a]oplanes4 ,,mi%&l+ ,,( ,,! ,,gr\nd4--,?is is ! cause ( a lot ( unnecess>y damage4 ,! gold5 rule to obs]ve is3 ,,produce ,,no ,,b5d+ ,,/resses4 ,ne>ly all ! wood 9 an a]oplane is design$ to take m]ely ! /ress ( direct compression1 & x _c be b5t safely4 ,!re=e1 9 pack+ an a]oplane up f ! gr\nd1 or 9 pull+ or pu%+ x ab\t1 be c>eful to /ress x 9 su* a way z to produce1 z f> z possible1 only direct compression /resses4 ,= in/ance1 if x is necess>y to support ! lift+ surface1 !n ! pack+ %\ld be arrang$ to come directly "u ! /ruts s t !y may take ! /ress 9 ! =m ( compression = :i* !y are design$4 ,su* supports %\ld be cov]$ ) s(t pack+ 9 ord] to prev5t ! fabric f becom+ damag$4 ,:5 pull+ an a]oplane along1 if possible1 pull f ! top ( ! und]c>riage /ruts4 ,if necess>y to pull f else:]e1 !n d s by grasp+ ! int]plane /ruts z l[ d[n z possible4 ,nev] lay fabric-cov]$ p>ts ^u a concrete floor4 ,any slight movem5t w cause ! fabric to scrape ov] ! floor ) resultant damage4 ,/ruts1 sp>s1 etc41 %\ld nev] be left ab\t ! floor1 z 9 su* position !y are likely to become scor$4 ,i h already expla9$ ! importance ( protect+ ! outside fibres ( ! wood4 ,rememb] also t wood becomes di/ort$ easily4 ,?is p>ticul>ly applies to int]plane /ruts4 ,if !re are no prop] racks to /& !m 91 !n ! be/ plan is to lean !m up aga9/ ! wall 9 z ne> a v]tical position z possible4 ,,"t4--,le>n to "k ! "t necess>y to complete any ( ! v>i\s rigg+ jobs4 ,?is is really important4 ,ignorance ( ?is w lead to bitt] disappo9tm5ts 9 civil life2 &1 :]e ,s]vice fly+ is conc]n$1 x w1 to say ! lea/ ( x1 e>n unpopul>ity ) s5ior (fic]s1 & fail to develop respect & good "w :]e m5 are conc]n$4 ,,! ,,a]oplane ,,%$4--,?is %\ld be kept z clean & ord]ly z possible4 ,a clean1 sm>t %$ produces briskness1 en]gy1 & pride ( "w4 ,a dirty1 disord]ly %$ ne>ly always produces slackness & poor quality ( "w1 lo/ tools & mislaid mat]ial4 ,,gloss>y ,a]onautics--,! sci5ce ( a]ial navigation4 ,a](oil--,a rigid /ructure1 ( l>ge sup]ficial area relative to its ?ickness1 design$ to obta91 :5 driv5 ?r\gh ! air at an angle incl9$ to ! direction ( motion1 a reaction f ! air approximately at "r angles to its surface4 ,always camb]$ :5 int5d$ to secure a reaction 9 "o direction only4 ,z ! t]m 8a](oil0 is h>dly ev] us$ 9 practical a]onautics1 ,i h1 ?r\gh\t ?is book1 us$ ! t]m ,,surface1 :i*1 :ile academically incorrect1 s9ce x does n indicate ?ickness1 is a t]m usually us$ to describe ! camb]$ lift+ surfaces1 i4e41 ! 8planes0 or 8w+s10 & ! /abiliz]s & ! controll+ a](oils4 ,a]odrome--,! "n usually appli$ to a gr\nd us$ = ! practice ( aviation4 ,x really means 8fly+ ma*9e10 b is nev] us$ 9 t s5se n[adays4 ,a]oplane--,a p[]-driv5 a](oil ) /abiliz+ & controll+ surfaces4 ,accel]ation--,! rate ( *ange ( velocity4 ,angle ( ,incid5ce--,! angle at :i* ! 8neutral lift l9e0 ( a surface attacks ! air4 ,angle ( ,incid5ce1 ,rigg]'s--,! angle ! *ord ( a surface makes ) a l9e p>allel to ! axis ( ! propell]4 ,angle ( ,incid5ce1 ,maximum--,! greate/ angle ( incid5ce at :i*1 = a giv5 p[]1 surface 7includ+ detrim5tal surface71 & weight1 horizontal flight c be ma9ta9$4 ,angle ( ,incid5ce1 ,m9imum--,! smalle/ angle ( incid5ce at :i*1 = a giv5 p[]1 surface 7includ+ detrim5tal surface71 & weight1 horizontal flight c be ma9ta9$4 ,angle ( ,incid5ce1 ,be/ ,climb+--,t angle ( incid5ce at :i* an a]oplane asc5ds quicke/4 ,an angle approximately halfway betwe5 ! maximum & optimum angles4 ,angle ( ,incid5ce1 ,optimum--,! angle ( incid5ce at :i* ! lift-drift ratio is ! highe/4 ,angle1 ,glid+--,! angle betwe5 ! horizontal & ! pa? along :i* an a]oplane at normal fly+ spe$1 b n "u eng9e p[]1 desc5ds 9 /ill air4 ,angle1 ,dih$ral--,! angle betwe5 two planes4 ,angle1 ,lat]al ,dih$ral--,! lift+ surface ( an a]oplane is said to be at a lat]al dih$ral angle :5 x is incl9$ upw>d t[>ds its w+-tips4 ,angle1 ,longitud9al ,dih$ral--,! ma9 surface & tail surface are said to be at a longitud9al dih$ral angle :5 ! projections ( _! neutral lift l9es meet & produce an angle above !m4 ,angle1 ,rigg]'s ,longitud9al ,dih$ral--,ditto1 b sub/itut+ 8*ords0 = 8neutral life l9es40 ,angle1 ,pit*--,! angle at any giv5 po9t ( a propell]1 at :i* ! blade is incl9$ to ! direction ( motion :5 ! propell] is revolv+ b ! a]oplane /ation>y4 ,altimet]--,an in/rum5t us$ = measur+ height4 ,air-,spe$ ,indicator--,an in/rum5t us$ = measur+ air pressures or velocities4 ,x consequ5tly indicates :e!r ! surface is secur+ ! requisite reaction = flight4 ,usually calibrat$ 9 miles p] h\r1 9 :i* case x indicates ! correct numb] ( miles p] h\r at only "o altitude4 ,?is is ow+ to ! d5sity ( ! air decreas+ ) increase ( altitude & necessitat+ a great] spe$ ?r\gh space to secure ! same air pressure z w\ld be secur$ by less spe$ at a l[] altitude4 ,x w\ld be m correct to calibrate x 9 units ( air pressure4 ,air ,pocket--,a local movem5t or condition ( ! air caus+ an a]oplane to drop or lose its correct attitude4 ,aspect-,ratio--,! proportion ( span to *ord ( a surface4 ,air-,screw 7,propell]7--,a surface s %ap$ t its rotation ab\t an axis produces a =ce 7?ru/7 9 ! direction ( its axis4 ,ail]on--,a controll+ surface1 usually situat$ at ! w+-tip1 ! op]ation ( :i* turns an a]oplane ab\t its longitud9al axis2 causes an a]oplane to tilt sideways4 ,aviation--,! art ( driv+ an a]oplane4 ,aviator--,! driv] ( an a]oplane4 ,b>ograph--,a record+ b>omet]1 ! *>ts ( :i* c be calibrat$ = %[+ air d5sity or height4 ,b>omet]--,an in/rum5t us$ = indicat+ ! d5sity ( air4 ,bank1 to--,to turn an a]oplane ab\t its longitud9al axis 7to tilt sideways7 :5 turn+ to left or "r4 ,biplane--,an a]oplane ( :i* ! ma9 lift+ surface consi/s ( a surface or pair ( w+s m\nt$ above ano!r surface or pair ( w+s4 ,bay--,! space enclos$ by two /ruts & :atev] !y are fix$ to4 ,boom--,a t]m usually appli$ to ! long sp>s jo9+ ! tail ( a 8pu%]0 a]oplane to its ma9 lift+ surface4 ,brac+--,a sy/em ( /ruts & tie wires to transf] a =ce f "o po9t to ano!r4 ,can>d--,lit]ally 8duck40 ,! "n :i* 0 giv5 to a type ( a]oplane ( :i* ! longitud9al /abiliz+ surface 7emp5nage7 0 m\nt$ 9 front ( ! ma9 lift+ surface4 ,sometimes t]m$ 8tail-fir/0 a]oplanes1 b su* t]m is errone\s1 z 9 su* a design ! ma9 lift+ surface acts z1 & is1 ! emp5nage4 ,cabre--,to fly or glide at an excessive angle ( incid5ce2 tail d[n4 ,camb]--,curvature4 ,*ord--,usually tak5 to be a /raight l9e betwe5 ! trail+ & lead+ edges ( a surface4 ,cell--,! :ole ( ! l[] surface1 t "p ( ! upp] surface directly ov] x1 toge!r ) ! /ruts & wires hold+ !m toge!r4 ,c5tre 7,l9e7 ( ,pressure--,a l9e runn+ f w+-tip to w+-tip1 & ?r\gh :i* all ! air =ces act+ ^u ! surface may be said to act1 or ab\t :i* !y may be said to balance4 ,c5tre 7,l9e7 ( ,pressure1 ,resultant--,a l9e transv]se to ! longitud9al axis1 & ! position ( :i* is ! resultant ( ! c5tres ( pressure ( two or m surfaces4 ,c5tre ( ,gravity--,! c5tre ( weight4 ,cabane--,a comb9ation ( two pylons1 situat$ ov] ! fuselage1 & f :i* anti-lift wires are susp5d$4 ,clo*e--,lit]ally 8bell40 ,is appli$ to ! bell-%ap$ con/ruction :i* =ms ! l[] "p ( ! pilot's control lev] 9 a ,bl]iot monoplane1 & to :i* ! control cables are atta*$4 ,c5trifugal ,=ce--,e body :i* moves 9 a curv$ pa? is urg$ outw>ds f ! c5tre ( ! curve by a =ce t]m$ 8c5trifugal40 ,control ,lev]--,a lev] by means ( :i* ! controll+ surfaces are op]at$4 ,x usually op]ates ! ail]ons & elevator4 ,! 8joy-/ick04 ,cavitation1 ,propell]--,! t5d5cy to produce a cavity 9 ! air4 ,di/ance ,piece--,a long1 ?9 piece ( wood 7sometimes tape7 pass+ ?r\gh & atta*$ to all ! ribs 9 ord] to prev5t !m f roll+ ov] sideways4 ,displacem5t--,*ange ( position4 ,drift 7( an a]oplane z di/9ct f ! propell]7--,! horizontal compon5t ( ! reaction produc$ by ! action ( driv+ ?r\gh ! air a surface incl9$ upw>ds & t[>ds its direction ( motion ,,plus ! horizontal compon5t ( ! reaction produc$ by ! 8detrim5tal0 surface ,,plus resi/ance due to 8sk9-friction40 ,sometimes t]m$ 8head-resi/ance40 ,drift1 ,active--,drift produc$ by ! lift+ surface4 ,drift1 ,passive--,drift produc$ by ! detrim5tal surface4 ,drift 7( a propell]7--,analog\s to ! drift ( an a]oplane4 ,x is conv5i5t to include 8cavitation0 )9 ?is t]m4 ,drift1 to--,to be c>ri$ by a curr5t ( air2 to make leeway4 ,dive1 to--,to desc5d s /eeply z to produce a spe$ great] ?an ! normal fly+ spe$4 ,dope1 to--,to pa9t a fabric ) a special fluid = ! purpose ( tight5+ & protect+ x4 ,d5sity--,mass ( unit volume1 = in/ance1 p\nds p] cubic foot4 ,effici5cy--,output ,input ,effici5cy 7( an a]oplane z di/9ct f eng9e & propell]7-- ,lift & ,velocity ,?ru/ 7 a]oplane drift7 ,effici5cy1 ,eng9e--,brake horse-p[] ,indicat$ horse-p[] ,effici5cy1 ,propell]-- ,?ru/ horse-p[] ,horse-p[] receiv$ f eng9e 7 propell] drift7 ,,note4--,! above t]ms c1 ( c\rse1 be express$ 9 foot-p\nds4 ,x is !n only necess>y to divide ! upp] t]m by ! l[] "o to f9d ! measure ( effici5cy4 ,elevator--,a controll+ surface1 usually h+$ to ! re> ( ! tail-plane1 ! op]ation ( :i* turns an a]oplane ab\t an axis :i* is transv]se to ! direction ( normal horizontal flight4 ,emp5nage--,see 8,tail-plane40 ,en]gy--,/or$ "w4 ,= in/ance1 a giv5 weight ( coal or petroleum /ores a giv5 quantity ( en]gy :i* may be express$ 9 foot-p\nds4 ,ext5sion--,t "p ( ! upp] surface ext5d+ beyond ! span ( ! l[] surface4 ,edge1 ,lead+--,! front edge ( a surface relative to its normal direction ( motion4 ,edge1 ,trail+--,! re> edge ( a surface relative to its normal direction ( motion4 ,factor ( ,safety--,usually tak5 to mean ! result f\nd by divid+ ! /ress at :i* a body w collapse by ! maximum /ress x w be call$ ^u to be>4 ,f95ess 7( /ream-l9e7--,! proportion ( l5g? to maximum wid?4 ,fly+ ,position--,a special position 9 :i* an a]oplane mu/ be plac$ :5 rigg+ x or mak+ adju/m5ts4 ,x v>ies ) diff]5t types ( a]oplanes4 ,w\ld be m correctly describ$ z 8rigg+ position40 ,fuselage--,t "p ( an a]oplane conta9+ ! pilot1 & to :i* is fix$ ! tail-plane4 ,f9--,additional keel-surface1 usually m\nt$ at ! re> ( an a]oplane4 ,flange 7( a rib7--,t horizontal "p ( a rib :i* prev5ts x f b5d+ sideways4 ,flight--,! su/5ance ( a body heavi] ?an air by means ( its action ^u ! air4 ,foot-p\nd--,a measure ( "w repres5t+ ! weight ( #a lb4 rais$ #a foot4 ,fair+--,usually made ( ?9 %eet alum9um1 wood1 or a light con/ruction ( wood & fabric2 & b5t r\nd detrim5tal surface 9 ord] to give x a 8fair0 or 8/ream-l0 %ape4 ,gravity--,is ! =ce ( ! ,e>?'s attraction ^u a body4 ,x decreases ) increase ( di/ance f ! ,e>?4 ,see 8,weight40 ,gravity1 ,specific--,d5sity ( sub/ance ,d5sity ( wat]4 ,?us1 if ! d5sity ( wat] is #aj lb4 p] unit volume1 ! same unit volume ( petrol1 if weigh+ #g lb41 w\ld be said to h a specific gravity ( #g_/aj1 i4e41 #j4g4 ,gap 7( an a]oplane7--,! di/ance betwe5 ! upp] & l[] surfaces ( a biplane4 ,9 a triplane or multiplane1 ! di/ance betwe5 a surface & ! "o fir/ above x4 ,gap1 ,propell]--,! di/ance1 measur$ 9 ! direction ( ! ?ru/1 betwe5 ! spiral c\rses ( ! blades4 ,gird]--,a /ructure design$ to resi/ b5d+1 & to comb9e lightness & /r5g?4 ,gyroscope--,a heavy circul> :eel revolv+ at high spe$1 ! effect ( :i* is a t5d5cy to ma9ta9 its plane ( rotation aga9/ di/urb+ =ces4 ,hang>--,an a]oplane %$4 ,head-,resi/ance--,drift4 ,! resi/ance ( ! air to ! passage ( a body4 ,helicopt]--,an air-screw revolv+ ab\t a v]tical axis1 ! direction ( its ?ru/ be+ oppos$ to gravity4 ,horizontal ,equival5t--,! plan view ( a body :atev] its attitude may be4 ,impulse--,a =ce caus+ a body to ga9 or lose mom5tum4 ,incl9omet]--,a curv$ =m ( _s-level us$ = indicat+ ! attitude ( a body relative to ! horizontal4 ,in/ability--,an inh]5t t5d5cy ( a body1 :i*1 if ! body is di/urb$1 causes x to move into a position z f> z possible away f its fir/ position4 ,in/ability1 ,neutral--,an inh]5t t5d5cy ( a body to rema9 9 ! position giv5 x by ! =ce ( a di/urbance1 ) no t5d5cy to move f>!r or to return to its fir/ position4 ,in]tia--,! inh]5t resi/ance to displacem5t ( a body z di/9ct f resi/ance ! result ( an ext]nal =ce4 ,joy-,/ick--,see 8,control ,lev]40 ,keel-,surface--,ev]y?+ to be se5 :5 view+ an a]oplane f ! side ( x4 ,k+-,po/--,a brac+ /rut2 9 an a]oplane1 usually pass+ ?r\gh a surface & atta*$ to ! ma9 sp>1 & f ! end or ends ( :i* wires are tak5 to sp>1 surface1 or o!r "p ( ! con/ruction 9 ord] to prev5t di/ortion4 ,:5 us$ 9 connection ) a controll+ surface1 x usually p]=ms ! additional function ( a lev]1 control cables connect+ its ends ) ! pilot's control lev]4 ,lift--,! v]tical compon5t ( ! reaction produc$ by ! action ( driv+ ?r\gh ! air a surface incl9$ upw>ds & t[>ds its direction ( motion4 ,lift1 ,m>g9 (--,! height an a]oplane c ga9 9 a giv5 "t & />t+ f a giv5 altitude4 ,lift-,drift ,ratio--,! proportion ( lift to drift4 ,load+--,! weight c>ri$ by an a](oil4 ,usually express$ 9 p\nds p] squ>e foot ( sup]ficial area4 ,long]on--,! t]m usually appli$ to any long sp> runn+ l5g?-ways ( a fuselage4 ,mass--,! mass ( a body is a measure ( ! quantity ( mat]ial 9 x4 ,mom5tum--,! product ( ! mass & velocity ( a body is kn[n z 8mom5tum40 ,monoplane--,an a]oplane ( :i* ! ma9 lift+ surface consi/s ( "o surface or "o pair ( w+s4 ,multiplane--,an a]oplane ( :i* ! ma9 lift+ surface consi/s ( num]\s surfaces or pairs ( w+s m\nt$ "o above ! o!r4 ,montant--,fuselage /rut4 ,nacelle--,t "p ( an a]oplane conta9+ ! eng9e & pilot & pass5g]1 & to :i* ! tail plane is n fix$4 ,neutral ,lift ,l9e--,a l9e tak5 ?r\gh a surface 9 a =w>d direction relative to its direction ( motion1 & />t+ f its trail+ edge4 ,if ! attitude ( ! surface is su* z to make ! said l9e co9cid5t ) ! direction ( motion1 x results 9 no lift1 ! reaction !n consi/+ solely ( drift4 ,! position ( ! neutral lift l9e1 i4e41 ! angle x makes ) ! *ord1 v>ies ) diff]5ces ( camb]1 & x is f\nd by means ( w9d-tunnel rese>*4 ,newton's ,laws ( ,motion--#a4 ,if a body be at re/1 x w rema9 at re/2 or1 if 9 motion1 x w move uni=mly 9 a /raight l9e until act$ ^u by "s =ce4 #b4 ,! rate ( *ange ( ! quantity ( motion 7mom5tum7 is proportional to ! =ce :i* causes x1 & takes place 9 ! direction ( ! /raight l9e 9 :i* ! =ce acts4 ,if a body be act$ ^u by sev]al =ces1 x w obey ea* z ?\gh ! o!rs did n exi/1 & ?is :e!r ! body be at re/ or 9 motion4 #c4 ,to e action !re is oppos$ an equal & opposite reaction4 ,orni?opt] 7or ,or?opt]7--,a flapp+ w+ design ( aircraft int5d$ to imitate ! flight ( a bird4 ,outrigg]--,?is t]m is usually appli$ to ! framework connect+ ! ma9 surface ) an elevator plac$ 9 advance ( x4 ,sometimes appli$ to ! 8tail-boom0 framework connect+ ! tail-plane ) ! ma9 lift+ surface4 ,pancake1 to--,to 8/all 0 ,plane--,?is t]m is (t5 appli$ to a lift+ surface4 ,su* application is n q correct1 s9ce 8plane0 indicates a flat surface1 & ! lift+ surfaces are always camb]$4 ,propell]--,see 8,air-,screw40 ,propell]1 ,tractor--,an air-screw m\nt$ 9 front ( ! ma9 lift+ surface4 ,propell]1 ,pu%]--,an air-screw m\nt$ beh9d ! ma9 lift+ surface4 ,pu%]--,an a]oplane ( :i* ! propell] is m\nt$ beh9d ! ma9 lift+ surface4 ,pylon--,any ,v-%ap$ con/ruction f ! po9t ( :i* wires are tak54 ,p[]--,rate ( work+4 ,p[]1 ,horse--,"o horse-p[] repres5ts a =ce suffici5t to raise #cc1jjj lbs4 #a foot 9 a m9ute4 ,p[]1 ,indicat$ ,horse--,! ,i4,h4,p4 ( an eng9e is a measure ( ! rate at :i* "w is done by ! pressure ^u ! pi/on or pi/ons1 z di/9ct f ! rate at :i* ! eng9e does "w4 ,! latt] is usually t]m$ 8brake horse-p[]10 s9ce x may be measur$ by an absorption brake4 ,p[]1 ,m>g9 (--,! available quantity ( p[] above t necess>y to ma9ta9 horizontal flight at ! optimum angle4 ,pitot ,tube--,a =m ( air-spe$ indicator consi/+ ( a tube ) op5 end fac+ ! w9d1 :i*1 comb9$ ) a /atic pressure or suction tube1 is us$ 9 conjunction ) a gauge = measur+ air pressures or velocities4 7,no4 #a 9 diagram47 ,pit*1 ,propell]--,! di/ance a propell] advances dur+ "o revolution suppos+ ! air to be solid4 ,pit*1 to--,to plunge nose-d[n4 ,reaction--,a =ce1 equal & opposite to ! =ce ( ! action produc+ x4 ,rudd]--,a controll+ surface1 usually h+$ to ! tail1 ! op]ation ( :i* turns an a]oplane ab\t an axis :i* is v]tical 9 normal horizontal flight2 causes an a]oplane to turn to left or "r ( ! pilot4 ,roll1 to--,to turn ab\t ! longitud9al axis4 ,rib1 ,ord9>y--,a light curv$ wood5 "p m\nt$ 9 a =e & aft direction )9 a surface4 ,! ord9>y ribs give ! surface its camb]1 c>ry ! fabric1 & transf] ! lift f ! fabric to ! sp>s4 ,rib1 ,compression--,acts z an ord9>y rib1 besides be>+ ! /ress ( compression produc$ by ! t5sion ( ! int]nal brac+ wires4 ,rib1 ,false--,a subsidi>y rib1 usually us$ to improve ! camb] ( ! front "p ( ! surface4 ,"r & ,left ,h&--,always us$ relative to ! position ( ! pilot4 ,:5 obs]v+ an a]oplane f ! front ( x1 ! "r h& side ( x is !n on ! left h& ( ! obs]v]4 ,rem\--,a local movem5t or condition ( ! air :i* may cause displacem5t ( an a]oplane4 ,rudd]-,b>--,a control lev] mov$ by ! pilot's feet1 & op]at+ ! rudd]4 ,surface--,see 8,a](oil40 ,surface1 ,detrim5tal--,all ext]ior p>ts ( an a]oplane includ+ ! propell]1 b exclud+ ! 7a]oplane7 lift+ & 7propell]7 ?ru/+ surfaces4 ,surface1 ,controll+--,a surface ! op]ation ( :i* turns an a]oplane ab\t "o ( its axes4 ,sk9-,friction--,! friction ( ! air ) r\ghness ( surface4 ,a =m ( drift4 ,span---,! di/ance f w+-tip to w+-tip4 ,/agg]--,! di/ance ! upp] surface is =w>d ( ! l[] surface :5 ! axis ( ! propell] is horizontal4 ,/ability--,! inh]5t t5d5cy ( a body1 :5 di/urb$1 to return to its normal position4 ,/ability1 ,directional--,! /ability ab\t an axis :i* is v]tical dur+ normal horizontal flight1 & )\t :i* an a]oplane has no natural t5d5cy to rema9 ^u its c\rse4 ,/ability1 ,longitud9al--,! /ability ( an a]oplane ab\t an axis transv]se to ! direction ( normal horizontal flight1 & )\t :i* x has no t5d5cy to oppose pit*+ & toss+4 ,/ability1 ,lat]al--,! /ability ( an a]oplane ab\t its longitud9al axis1 & )\t :i* x has no t5d5cy to oppose sideways roll+4 ,/abiliz]--,a surface1 su* z f9 or tail-plane1 design$ to give an a]oplane inh]5t /ability4 ,/all1 to--,to give or all[ an a]oplane an angle ( incid5ce great] ?an ! 8maximum0 angle1 ! result be+ a fall 9 ! lift-drift ratio1 ! lift consequ5tly becom+ less ?an ! weight ( ! a]oplane1 :i* mu/ !n fall1 i4e41 8/all0 or 8pancake40 ,/ress--,burd5 or load4 ,/ra9--,de=mation produc$ by /ress4 ,side-,slip1 to--,to fall z a result ( an excessive 8bank0 or 8roll40 ,skid1 to--,to be c>ri$ sideways by c5trifugal =ce :5 turn+ to left or "r4 ,skid1 ,und]c>riage--,a sp>1 m\nt$ 9 a =e & aft direction1 & to :i* ! :eels ( ! und]c>riage are sometimes atta*$4 ,%\ld a :eel give way ! skid is !n suppos$ to act l ! runn] ( a sleigh & to support ! a]oplane4 ,skid1 ,tail--,a piece ( wood or o!r mat]ial1 ori5table1 & fitt$ ) %ock absorb]s1 situat$ "u ! tail ( an a]oplane 9 ord] to support x ^u ! gr\nd & to absorb ! %ock ( alight+4 ,section--,any sep>ate "p ( ! top surface1 t "p ( ! bottom surface imm$iately und]nea? x1 ) _! /ruts & wires4 ,sp>--,any long piece ( wood or o!r mat]ial4 ,sp>1 ,ma9--,a sp> )9 a surface & to :i* all ! ribs are atta*$1 su* sp> be+ ! "o situat$ ne>e/ to ! c5tre ( pressure4 ,x transf]s m ?an half ! lift f ! ribs to ! brac+4 ,sp>1 ,re>--,a sp> )9 a surface1 & to :i* all ! ribs are atta*$1 su* sp> be+ situat$ at ! re> ( ! c5tre ( pressure & at a great] di/ance f x ?an is ! ma9 sp>4 ,x transf]s less ?an half ( ! lift f ! ribs to ! brac+4 ,/rut--,any wood5 memb] int5d$ to take m]ely ! /ress ( direct compression4 ,/rut1 ,int]plane--,a /rut hold+ ! top & bottom surfaces ap>t4 ,/rut1 ,fuselage--,a /rut hold+ ! fuselage long]ons ap>t4 ,x %\ld be /at$ :e!r top1 bottom1 or side4 ,if side1 !n x %\ld be /at$ :e!r "r or left h&4 ,montant4 ,/rut1 ,ext5sion--,a /rut support+ an 8ext5sion0 :5 n 9 flight4 ,x may also prev5t ! ext5sion f collaps+ upw>ds dur+ flight4 ,/rut1 ,und]c>riage-- ,/rut1 ,dope--,a /rut )9 a surface1 s plac$ z to prev5t ! t5sion ( ! dop$ fabric f di/ort+ ! framework4 ,s]v+--,to b9d r\nd ) wire1 cord1 or simil> mat]ial4 ,usually us$ 9 connection ) wood jo9ts & wire cable splices4 ,slip1 ,propell]--,! pit* less ! di/ance ! propell] advances dur+ "o revolution4 ,/ream-,l9e--,a =m or %ape ( detrim5tal surface design$ to produce m9imum drift4 ,toss1 to--,to plunge tail-d[n4 ,torque1 ,propell]--,! t5d5cy ( a propell] to turn an a]oplane ab\t its longitud9al axis 9 a direction opposite to t 9 :i* ! propell] revolves4 ,tail-,slide--,a fall :]eby ! tail ( an a]oplane leads4 ,tractor--,an a]oplane ( :i* ! propell] is m\nt$ 9 front ( ! ma9 lift+ surface4 ,triplane--,an a]oplane ( :i* ! ma9 lift+ surface consi/s ( ?ree surfaces or pairs ( w+s m\nt$ "o above ! o!r4 ,tail-,plane--,a horizontal /abiliz+ surface m\nt$ at "s di/ance beh9d ! ma9 lift+ surface4 ,emp5nage4 ,turnbuckle--,a =m ( wire-tight5]1 consi/+ ( a b>rel into ea* end ( :i* is screw$ an eyebolt4 ,wires are atta*$ to ! eyebolts & ! requir$ degree ( t5sion is secur$ by means ( rotat+ ! b>rel4 ,?ru/1 ,propell]--,see 8,air-,screw40 ,und]c>riage--,t "p ( an a]oplane b5ea? ! fuselage or nacelle1 & int5d$ to support ! a]oplane :5 at re/1 & to absorb ! %ock ( alight+4 ,velocity--,rate ( displacem5t2 spe$4 ,volplane--,a glid+ desc5t4 ,weight--,is a measure ( ! =ce ( ! ,e>?'s attraction 7gravity7 ^u a body4 ,! /&>d unit ( weight 9 ?is c\ntry is #a lb41 & is ! =ce ( ! ,e>?'s attraction on a piece ( plat9um call$ ! /&>d p\nd1 deposit$ ) ! ,bo>d ( ,trade 9 ,london4 ,at ! c5tre ( ! ,e>? a body w be attract$ ) equal =ce 9 e direction4 ,x w !re=e h no weight1 ?\gh its mass is un*ang$4 ,gravity1 ( :i* weight is a measure1 decreases ) increase ( altitude4 ,web 7( a rib7--,t v]tical "p ( a rib :i* prev5ts x f b5d+ upw>ds4 ,w>p1 to--,to di/ort a surface 9 ord] to v>y its angle ( incid5ce4 ,to v>y ! angle ( incid5ce ( a controll+ surface4 ,wa%--,! di/urbance ( air produc$ by ! flight ( an a]oplane4 ,wa%-9--,an increas+ angle ( incid5ce ( a surface t[>ds its w+-tip4 ,wa%-out--,a decreas+ angle ( incid5ce ( a surface t[>ds its w+-tip4 ,w+-tip--,! "r- or left-h& extremity ( a surface4 ,wire--,a wire is1 9 ,a]onautics1 always kn[n by ! "n ( its function4 ,wire1 ,lift or ,fly+--,a wire oppos$ to ! direction ( lift1 & us$ to prev5t a surface f collaps+ upw>d dur+ flight4 ,wire1 ,anti-lift or ,l&+--,a wire oppos$ to ! direction ( gravity1 & us$ to su/a9 a surface :5 x is at re/4 ,wire1 ,drift--,a wire oppos$ to ! direction ( drift1 & us$ to prev5t a surface f collaps+ backw>ds dur+ flight4 ,wire1 ,anti-drift--,a wire oppos$ to ! t5sion ( a drift wire1 & us$ to prev5t su* t5sion f di/ort+ ! framework4 ,wire1 ,incid5ce--,a wire runn+ f ! top ( an int]plane /rut to ! bottom ( ! int]plane /rut 9 front ( or beh9d x4 ,x ma9ta9s ! 8/agg]0 & assi/s 9 ma9ta9+ ! angle ( incid5ce4 ,sometimes t]m$ 8/agg] wire40 ,wire1 ,brac+--,any wire hold+ toge!r ! framework ( any "p ( an a]oplane4 ,x is n1 h[ev]1 usually appli$ to ! wires describ$ above unless ! function p]=m$ includes a function additional to ^? describ$ above4 ,?us1 a lift wire1 :ile /rictly speak+ a brac+ wire1 is n usually describ$ z "o unless x p]=ms ! additional function ( brac+ "s well-def9$ "p su* z ! und]c>riage4 ,x w !n be said to be an 8und]c>riage brac+ lift wire40 ,x might1 p]haps1 be act+ z a drift wire also1 9 :i* case x w !n be de-scrib$ z an 8und]c>riage brac+ lift-drift wire40 ,x %\ld always be /at$ :e!r a brac+ wire is 7#a7 top1 7#b7 bottom1 7#c7 cross1 or 7#d7 side4 ,if a 8side brac+ wire10 !n x %\ld be /at$ :e!r "r- or left-h&4 ,wire1 ,int]nal ,brac+--,a brac+ wire 7usually drift or anti-drift7 )9 a surface4 ,wire1 ,top ,brac+--,a brac+ wire1 approximately horizontal & situat$ betwe5 ! top long]ons ( fuselate1 betwe5 top tail booms1 or at ! top ( simil> con/ruction4 ,wire1 ,bottom ,brac+--,ditto1 sub/itut+ 8bottom0 = 8top40 ,wire1 ,side ,brac+--,a brac+ wire cross+ diagonally a side bay ( fuselage1 tail boom bay1 und]c>riage side bay or c5tre-section side bay4 ,?is t]m is n usually us$ ) ref]5ce to incid5ce wires1 al?\gh !y cross diagonally ! side bays ( ! cell4 ,x %\ld be /at$ :e!r "r- or left-h&4 ,wire1 ,cross ,brac+--,a brac+ wire1 ! position ( :i* is diagonal f "r to left :5 view+ x f ! front ( an a]oplane4 ,wire1 ,control ,brac+--,a wire prev5t+ di/ortion ( a controll+ surface4 ,wire1 ,control--,a wire connect+ a controll+ surface ) ! pilot's control lev]1 :eel1 or rudd]-b>4 ,wire1 ,ail]on ,gap--,a wire connect+ top & bottom ail]ons4 ,wire1 ,ail]on ,balance--,a wire connect+ ! "r- & left-h& top ail]ons4 ,sometimes t]m$ ! 8ail]on comp5sat+ wire40 ,wire1 ,snak+--,a wire1 usually ( s(t metal1 w\nd spirally or ti$ r\nd ano!r wire1 & atta*$ at ea* end to ! framework4 ,us$ to prev5t ! wire r\nd :i* x is 8snak$0 f becom+1 9 ! ev5t ( its displacem5t1 entangl$ ) ! propell]4 ,wire1 ,lock+--,a wire us$ to prev5t a turnbuckle b>rel or o!r fitt+ f los+ its adju/m5t4 ,w+--,/rictly speak+1 a w+ is "o ( ! surfaces ( an orni?opt]4 ,! t]m is1 h[ev]1 (t5 appli$ to ! lift+ surface ( an a]oplane :5 su* surface is divid$ into two p>ts1 "o be+ ! left-h& 8w+10 & ! o!r ! "r-h& 8w+40 ,w9d-,tunnel--,a l>ge tube us$ = exp]im5t+ ) surfaces & models1 & ?r\gh :i* a curr5t ( air is made to fl[ by artificial means4 ,"w--,=ce ,x displacem5t4 ,w9d-,scre5--,a small transp>5t scre5 m\nt$ 9 front ( ! pilot to protect 8 face f ! air pressure4 ,,footnotes3 #a ,propell] ,slip3 ,z ! propell] screws ?r\gh ! air1 ! latt] to a c]ta9 ext5t gives back to ! ?ru/ ( ! propellor blades1 j z ! %+le on ! bea* slips back z y asc5d x4 ,su* 8give-back0 is kn[n z 8slip10 & anyone beh9d ! propellor w feel ! slip z a /rong draught ( air4 #b ,helicopt]4 ,an air-screw revolv+ ^u a v]tical axis4 ,if driv5 ) suffici5t p[]1 x w lift v]tically1 b hav+ reg>d to ! me*anical difficulties ( su* con/ruction1 x is a mo/ ineffici5t way ( secur+ lift comp>$ ) ! arrangem5t ( an incl9$ surface driv5 by a propell] revolv+ ab\t a horizontal axis4 #c ,pancakes3 ,pilot's slang = /all+ an a]oplane & dropp+ l a pancake4 #d ,morane p>asol3 ,a type ( ,morane monoplane 9 :i* ! lift+ surfaces are rais$ above ! pilot 9 ord] to af=d him a good view ( ! e>?4 #e ,sk9 friction is t "p ( ! drift due to ! friction ( ! air ) r\ghnesses ^u ! surface ( ! a]oplane4 #f ,bank+3 ,:5 an a]oplane is turn$ to ! left or ! "r ! c5trifugal =ce ( its mom5tum causes x to skid sideways & outw>ds away f ! c5tre ( ! turn4 ,to m9imize su* action ! pilot banks1 i4e41 tilts1 ! a]oplane sideways 9 ord] to oppose ! und]side ( ! planes to ! air4 ,! a]oplane w n !n skid outw>ds beyond ! slight skid necess>y to secure a suffici5t pressure ( air to balance ! c5trifugal =ce4 #g ,an explanation ( ! way 9 :i* ! wa%-out is comb9$ ) a wa%-9 to (fset propellor torque w be f\nd on p4 #hb4 #h ,a4,m4's3 ,air ,me*anics4 #i ,butt means to ?ick5 at ! end4 ,screw means to ma*9e a ?read on ! butt-end ( ! wire1 & 9 ?is way ! wire c make connection ) ! desir$ place by be+ screw$ into a metal fitt+1 ?us elim9at+ ! disadvantage ( ! unsatisfactory loop4 #aj ,deviation curve3 ,a curv$ l9e indicat+ any errors 9 ! compass4 #aa ,a propell] screws ?r\gh ! air1 & ! di/ance x advances dur+ "o revolution1 suppos+ ! air to be solid1 is kn[n z ! pit*4 ,! pit*1 :i* dep5ds ^u ! angle ( ! propell] blades1 mu/ be equal to ! spe$ ( ! a]oplane1 plus ! slip1 & if1 on acc\nt ( ! r>ity ( ! air ! spe$ ( ! a]oplane increases1 !n ! angle & pit* %\ld be correspond+ly increas$4 ,propell]s ) a pit* capable ( be+ v>i$ by ! pilot are ! dream ( propell] design]s4 ,= explanation ( 8slip0 see ,*apt] ,,iv4 on propell]s4 #ab ,gett+ out ( my dep?8 ,invad+ ! realms ( fancy8 ,well1 p]haps s1 b at any rate x is possible t extraord9>y spe$ ?r\gh space may be secur$ if means are f\nd to ma9ta9 ! impulse ( ! eng9e & ! ?ru/-drift effici5cy ( ! propell] at great altitude4 #ac ,box-kite4 ,! fir/ crude =m ( biplane4 #ad ,see ,newton's laws 9 ! ,gloss>y at ! end ( ! book4 #ae ,see 8,a](oil0 9 ! ,gloss>y4 #af 8,9 effect0 because1 al?\gh !re may be actually ! greate/ proportion ( keel-surface ,9 front ( ! v]tical axis1 su* surface may be mu* ne>] to ! axis ?an is ! keel-surface t[>ds ! tail4 ,! latt] may !n be actually less ?an ! surface 9 front1 b1 be+ f>!r f ! axis1 x has a great] lev]age1 & consequ5tly is great] 9 effect ?an ! surface 9 front4