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532 FLIGHT M A Y I 8 T H , 1944C a m e r aR e c o r d e rNe^tlawkey Instru'merit W rites TimeHistories of Accelerd'tion, Control M o v e ments and Stick ForcesU N T I L c o m p a r a t i v e l y r e c e n t l yt h e p e r f o r m a n c e o f a i rc r a f tw a s s u c h t h a t t h e t e s t p i l o tcou l d m ak e no t e s on h i s knee pa d o f a l l t h e i t em sw hi ch need ed t o be r eco r ded d u r i n g a t e s t f l i gh t .G r a d u a l l y n o t o n l y p e r f o r m a n c e b u t c o m p l e x i t y h a s g r o w nt o s u c h a n e x t e n t t h a t a t e s t p i lo t w o u l d n e e d s e v e r a l h a n d sa n d s e v e r a l p a i r s o f e y e s t o c o p e w i t h t h e m u l t i t u d e oft h i n g s t h a t h a v e t o b e d o n e s i m u l t a n e o u s l y . T h i s i s p a r t i cu l a r l y s o i n t he ca s e o f, f o r exa m p l e , a s i ng l e - s e a t e rf ighte r, pa r t l y beca us e o f i t s h i gh pe r f o r m anc e an d pa r t l ybecau s e t he p i j o t i s t h e on l y m em be r o f t h e c r ew . Am o der n f igh t e r c l i m b s a t ove r 3 ,000f t , pe r m i n . and t heT y p h o o n , f o r i n s t a n c e , h a s 17 d i a l s t o w a t c h . I n m u l t i -s ea t e r a i r c r a f t i t is u s u a l l y pos s i b l e t o ca r r y one o r m or eobs e r ve r s , e ach o f w hom has s om e s pec i f i c po r t i on o f t hee q u i p m e n t t o w a t c h .

A u t o m a t i c P h o t o g r a p h yI n h i s r e c e n t t a l k t o t h e L o n d o n A s s o c i a t i o n of E n g i n e e r sM r . L a n k e s t e r P a r k e r q u o t e d fr o m t h e l e c t u r e g i v e n b y

M r . E . T . J o n e s t o t h e R . A e . S . l a s t F e b r u a r y a p a s s a g ew hi ch s t r e s s ed t he de s i r e o f a l l engaged on t e s t w or k t or e p l a c e v i s u a l - r e a d i n g i n s t r u m e n t s b y r e c o r d i n g i n s t r u m e n t s . Su ch an ou t f i t ha s been i n u s e f o r s om e t i m e byH a w k e r A i r c r a f t , L t d . I t h a s b e e n d e s i g n e d b y M r . P . D .B e t t e r i d ge of t h e H aw ke r t e ch n i ca l s t a ff and i s , b r i e f l y , ab o x c o n t a i n i n g t h e u s u a l a i r c r a f t i n s t r u m e n t s a n d a n u m b e ro f D e s y n r e m o t e i n d i c a t o r s , l i g h t s f o r i l l u m i n a t i n g t h ei n s t r u m e n t s , a n d a c a m e r a f or p h o t o g r a p h i n g t h e m .T h e c a m e r a u s e d i n t h e H a w k e r c a m e r a r e c o r d e r i s aP a t h e s c o p e I I , w h i c h t a k e s 6 0 0 -7 0 0 f r a m e s o n 9. 5 m m .f ilm . P r o v i s i o n i s m ad e f o r t ak i ngs i ng l e s ho t s , t h e u s u a l 16 f r am espe r s econd w hen us ed a s a c i nec a m e r a , a n d a u t o m a t i c e x p o s u r e s

Fig. 1 . The Haw kercamera recorder as sembled, complete wi thcont rol uni t .

Fig, a. The recorderwith covers forcamera , swi tchgearand l ight box re moved. The panelof ins t rument d ia l sfits in the open endof the l ight box.

Fig . 5 . Diagramof the recorder.The i n s t r um en tboard is i l luminated by the lamps , 1 ; and photographed by the came ra , 2 .The base , 3 , car r ies tw o elec t romag nets ; 4 and 5 are se lec torswi tches ; 6 the cont rol uni t , an d 7 the gun-f i r ing but ton .Connect ions are made via mul t i -p lug sockets 8 , 9 and 10.Pow er supply an d lamp s are controlled by the on-off switcht i , and intervals are selected on the switch 12. Single shotsare selected on the switch, 13 ; 14 are w arn ing l :ghts .

a t 1 / 6 , 1 / 3 , 1 , 2 , ,4 , 8 , 12 an d 24s e c o n d s ' i n t e r v a l s . T h e p o w e rs u pp l y is t h a t o f t h e a i r c r a f t ( 24v o l t s , 1 5 a m p s . ) . T h e e n t i r eo u t f i t c o m p r i s e s t h e a c t u a lr e c o r d e r , a c o n t r o lu n i t , a n d t h e p i l o t ' so p e r a t i n g b u t t o n o nt h e c o n t r o l c o l u m n( a c t u a l l y t h e g u n -f i r i ng bu t t on ) .M a i n c o m p o n e n t sa r e s how n i n F i g . 5 .T h e i n s t r u m en tp a n e l f o r m s o n e e n dof t he r eco r de r box

a n d is m a d e q u i c k l yd e t a c h a b l e s o a s t of ac i l i t a t e a chan ge o fi n s t r u m e n t s . T h ep a n e l i s i l l u m i n a t e db y t h e l a m p s , 1 . h it h e t o p a n d b o t t o m '

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MA Y I 8 T H , 1944 FLIGHT 5 3 3of the box and is photographed by the camera,2, placed at the opposi te end of the box. Wide-angle lenses were not avai lable when the ins t rument was bu i l t , and so an ordina ry lens was usedin conjunct ion with two mirro rs . These can beseen in Fig . 2. The camera i s mounted on a r ig idbase, 3 , which also carr ies two elect romagnets .These opera te a ba lanced a rmatu re , wh ichoperates the camera control lever, raising it forsingle o r auto ma tic shots and d epressing it forcine exposu res . Auto ma t ic operat ion is controlled by selector switches, 4 and 5, which areof the automat ic telephone type.The pilot controls the operation of the recorder by means of the control unit , 6, and thegun-fi ring but ton, 7 . Th e power supply is v iathe plug-and-socket , 8 , on the control uni t .This , and the plug sockets 9 and 10 renderal l i tems readi ly and separately detachable.

I n t e r v a l E x p o s u r e sNormally the pi lo t wi l l wish to take photographs at fai r ly long intervals . Fo r ins tance,during a cl imb he may wish to take a picture

ev ery 12 seconds. To do this he switches on thepower supply and lamps by means of the on-offswitch, 11 , an d, w ith the switc h, 12, in the" a u t o " position selects the 12-second intervalon the 9-posi t ion s witch, 13. T he cam era is thenstarted by pressing and releasing the gun-firingbut ton 7 . I t cont inues to run and to take apicture every 12 seconds until the pilot againpresses and releases the but ton.For taking s ingle exposures the pi lo t swi tcheson an d, w ith switch 12 in either cine or autoposition, selects single shots by means of the9-position switch , 13. Single shots will then betaken each t ime the gun but ton is pressed a ndreleased.In certain f l ight tes ts , such as rapidmanoeuvre or a d ive, the changes in the quant i t ies which are being measured may be so rapidthat even the one-s ixth of a second intervalma y be too long. In suc h cases the pi lo t setsswitch 12 at " cine " and sw itch 13 at any thin gexcept s ingle shots . Th e cam era is then s tarte dby press ing and releas ing the but ton and cont inues to operate at cine frequency (16 framesper second) unt i l the gun but ton is again pressed.

Fig. 4. Front andback views of a typicalinstrument panel comprisingnormal flight-test instruments and18 Desyn remo te - reading indicators.

Fig. 3. Close-upof camera, switch-gear and controlunit with coversremoved.

Warning l ights (14 on Fig . 5) are provided on the cont rol uni t to indicate when and at what rate the recorderis operat ing.In the earl ier part of th is ar t icle reference was made toMr. Lankes te r Parker ' s quo ta t ion f rom Mr. Jones ' s l ec tu re .In that lecture Mr. Jones pointed out that , al though therewas a need to replace visual reading by ins t ruments , the recorded his tories of control movementsand ai rcraft responses must only be used to augment , and to give reasons for , the tes t p i lo t 'sassessment of controls , ai rcraft behaviour, etc.They must not , he said , be used by the engineer to prove on paper that the tes t p i lo t 'sgeneral assessment is wrong.There i s l i t tl e doub t th a t t here Mr . J oussexpressed a fundamenta l t ru th , and tha t , ashe said , the tes t p i lo t 's opinion must beacce pted as f inal. Neverthe less , wi th theapproach of jet -propel led ai rcraft reachingspeeds never before at tained, in cl imb as wel l asin horizontal f l ight , the recording outf i t seemsl ike ly to as sum e ever -g rea te r impor tance . TheHawker ins t rument jus t described is not , of course, t l .eonly on e, nor is i t cla ime d to be th e final wor d, b ut 11ma rks a very good beginning . Wh en pressure cabinsremove the physical l imi tat ions at present imposed on thetes t p i lo t , for ins tance in cl imb tes ts and dives , thout i l i ty of mechanical recorders may wel l be furthere x t e n d e d .