Flight tests of a one-man helicopter by Jean LuLu

N A S A TECHNICAL NOTE

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FLIGHT TESTS OF A ONE-MAN HELICOPTER A N D A COMPARISON OF ITS HANDLING QUALITIES WITH THOSE OF LARGER VTOL AIRCRAFT

by Terrell W. Feistel and Fred J. Drinkwater III Ames Research Center Moffett Field, Cali$

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

WASHINGTON, D. C.

OCTOBER 1965

TECH LIBRARY KAFB, NM

FLIGHT TESTS O F A ONE-MAN HELICOPTER AND A COMPARISON O F ITS HANDLING QUALITIES WITH THOSE O F LARGER VTOL AIRCRAFT

By Terrell W. Feistel and Fred J. Drinkwater I11 Ames Research Center Moffett Field, Calif.

NATIONAL AERONAUT ICs AND SPACE ADMlN ISTRAT ION For sale

by the Clearinghouse for Federal Scientific and Technical Information Price $1.00 Springfield, Virginia 22151

FLIGHT TESTS OF A ONE-i"

HELICOPTER AND A COMPARISON

OF I T S HANDLING QUALITIES WITH THOSE O F LARGER VTOL AIRCRAFT

By T e r r e l l W. F e i s t e l and Fred J. Drinkwater I11 Ames Research Center

SUMMARY A l i m i t e d f l i g h t t e s t program has been accomplished w i t h a one-man H i l l e r YROE-1 "Rotorcycle" ( g r o s s wt 2 500 l b ) t o h e l p determine c r i t e r i a f o r t h e handling q u a l i t i e s i n hover of WOL a i r c r a f t as a f f e c t e d by g r o s s weight.

The g e n e r a l l y h i g h o r d e r s of l o n g i t u d i n a l and l a t e r a l c o n t r o l power and damping i n h e r e n t w e r e found t o b e s a t i s f a c t o r y . The h i g h d i r e c t i o n a l c o n t r o l s e n s i t i v i t y , combined w i t h h i g h yaw response i n one d i r e c t i o n , w a s considered p o t e n t i a l l y dangerous. The l a t e r a l c o n t r o l power f o r t h i s c r a f t i s approximately t h e same as t h a t found necessary f o r s a t i s f a c t o r y c o n t r o l w i t h similar damping i n t e s t s of two o t h e r VTOL a i r c r a f t w i t h s u b s t a n t i a l l y g r e a t e r g r o s s weight. INTRODUCTION

The NASA has, i n r e c e n t y e a r s , been studying handling q u a l i t i e s c r i t e r i a f o r V/STOL a i r c r a f t ( r e f . 1). A major q u e s t i o n i s , how do s a t i s f a c t o r y and u n s a t i s f a c t o r y l i m i t s f o r hovering c o n t r o l power and damping v a r y w i t h s i z e and g r o s s weight? One form of s c a l i n g c r i t e r i a i s p r e s e n t e d i n r e f e r e n c e 2. Only l i m i t e d f l i g h t v e r i f i c a t i o n of t h e s e c r i t e r i a i s a v a i l a b l e , c h i e f l y w i t h v e h i c l e s i n t h e 3000-4000 pound g r o s s weight category (see, e.g., r e f . 3 ) . The H i l l e r YROE-1 Rotorcycle, w i t h a g r o s s weight of approximately 500 pounds, i s a t t h e bottom end of t h e weight spectrum f o r manned a i r c r a f t and a n o r d e r of magnitude away f r o m t h e X-14A (used i n r e f . 3 ) . It w a s s e l e c t e d f o r i n v e s t i g a t i n g c o n t r o l power requirements a t low g r o s s weights i n hope t h a t , t h e r e b y , some l i g h t would be shed on t h e i n f l u e n c e of s i z e and weight. DESCRIPTION OF TEST A R T I C U The H i l l e r YROE-1 Rotorcycle ( f i g . 1) w a s o r i g i n a l l y designed f o r t h e Armed S e r v i c e s as a simple, c o l l a p s i b l e , one-man h e l i c o p t e r f o r o b s e r v a t i o n and l i a i s o n purposes. F i g u r e 2'shows a three-view s k e t c h of t h e v e h i c l e . A s flown, i t s g r o s s weight w a s 515 pounds. The power p l a n t i s a 4 - c y l i n d e r , 2 - c y c l e , Nelson engine of 43 hp. The c r a f t i s d e s c r i b e d i n d e t a i l i n references 4 and 5 and r e s u l t s of p r e v i o u s Navy f l i g h t t e s t s are g i v e n i n r e f e r ences 6 and 7. -

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For the NASA f l i g h t t e s t s a small i n s t r u m e n t a t i o n package w a s hung i n a box underneath t h e p i l o t as shown i n f i g u r e 1. The package contained a h i g h frequency t r a n s m i t t e r t h a t t e l e m e t e r e d information on three channels, and a s i n g l e - a x i s rate-measuring gyro which could b e o r i e n t e d along any one of the t h r e e axes. A p o t e n t i o m e t e r w a s a l s o included f o r measuring t h e p o s i t i o n of t h e c o n t r o l b e i n g considered and a b u t t o n on t h e c o n t r o l s t i c k allowed t h e p i l o t t o s i g n a l the start of a maneuver. METHOD OF DATA mDUCTION The maneuver f o r o b t a i n i n g t h e c o n t r o l power-damping d a t a c o n s i s t e d of a c o n t r o l reversal i n p u t t o t h e c o n t r o l a f f e c t i n g t h e axis b e i n g considered ending i n a f i x e d c o n t r o l d e f l e c t i o n h e l d f o r 1 - 2 seconds. Thus, t h e f i r s t d e r i v a t i v e of t h e r e s u l t a n t angular v e l o c i t y abaut t h e given axis, as t h i s v e l o c i t y p a s s e s through zero a f t e r t h e reversal, r e p r e s e n t s the a n g u l a r a c c e l e r a t i o n corresponding t o t h e c o n t r o l d e f l e c t i o n . The m a x i m e x c u r s i o n of t h e a n g u l a r v e l o c i t y ( w i t h t h e c o n t r o l s t i l l h e l d f i x e d ) , when compared t o t h e p r e v i o u s l y determined angular a c c e l e r a t i o n , i n d i c a t e s t h e approximate v e l o c i t y damping, 1/~, about t h e axis. See r e f e r e n c e 8 f o r an a n a l y s i s of t h i s method. The angular a c c e l e r a t i o n corresponding t o t o t a l c o n t r o l d e f l e c t i o n w a s d e t e r mined b y p l o t t i n g a c c e l e r a t i o n s measured a g a i n s t p e r c e n t d e f l e c t i o n and f a i r i n g a s t r a i g h t l i n e through a l l t h e p o i n t s (assuming a l i n e a r v a r i a t i o n of i n i t i a l a n g u l a r a c c e l e r a t i o n w i t h c o n t r o l d e f l e c t i o n ) . The p i l o t r a t i n g s were based on t a s k s d e s c r i b e d i n t h e P i l o t Comments s e c t i o n . RESULTS AND DISCUSSION Since t o t a l c o n t r o l power r e q u i r e d f o r a given t a s k i n c l u d e s t h a t f o r c o r r e c t i n g d i s t u r b i n g i n p u t s , it w i l l depend on t h e t y p e of VTOL a i r c r a f t because of i n h e r e n t d i f f e r e n c e s i n g u s t s e n s i t i v i t y , e t c . I n s p i t e of t h i s it i s of i n t e r e s t t o examine c o n t r o l power requirements f o r a wide range of VTOL a i r c r a f t t o observe any g r o s s t r e n d of t h e e f f e c t of s i z e . Table I i s a summary of t h e p e r t i n e n t parameters determined. It shows m a x i m u m c o n t r o l power ( i n terms of i n i t i a l a n g u l a r a c c e l e r a t i o n ) , a n g u l a r r a t e damping ( i n terms of t h e r e c i p r o c a l of the t i m e c o n s t a n t , l / - i - ) , c o n t r o l s e n s i t i v i t y ( i n terms of i n i t i a l a c c e l e r a t i o n p e r i n c h of c o n t r o l d e f l e c t i o n ) , and t h e p i l o t r a t i n g f o r the visual hovering t a s k ( f o r b o t h maximum c o n t r o l power and s e n s i t i v i t y , where a v a i l a b l e ) on t h e Cooper S c a l e ( t a b l e I1 and r e f . 9 ) f o r each of t h e three axes (two p i l o t r a t i n g s are shown; p i l o t A b e i n g t h e p r o j e c t p i l o t and p i l o t B a v i s i t i n g NASA p i l o t who made only one f l i g h t ) . For the d i r e c t i o n a l c a s e values are shown f o r r i g h t yaw only. A l s o shown are t h e implied v a l u e s of t h e c o n t r o l power, damping, and s e n s i t i v i t y c a l l e d o u t i n t h e proposed V/STOL s p e c i f i c a t i o n s ( r e f . 2 ) . These have been converted from t h e response v a l u e s l i s t e d by assuming a " s t e p " i n p u t t o t h e c o n t r o l . For comparison similar d a t a are shown, i n p a r a l l e l grouping, f o r t h e minimal s a t i s f a c t o r y (P.R. = 3.5) r a t i n g i n t h e v a r i a b l e s t a b i l i t y X-14A (used i n r e f . 3 ) . A l s o shown i n t h e "damping" column are t h e nominal moments of i n e r t i a of t h e two c r a f t i n s l u g - f t 2 .

Lateral Characteristic s Figure 3 shows a p l o t of t h e i n i t i a l a c c e l e r a t i o n i n roll f o r f u l l cont r o l d e f l e c t i o n ( i . e . , c o n t r o l power) and f o r one inch of c o n t r o l t r a v e l ( i . e . , s e n s i t i v i t y ) versus g r o s s weight f o r f o u r v e h i c l e s : t h e YROE-1 h e l i c o p t e r ( W = 515 l b ) , t h e X-14A d e f l e c t e d j e t VTOL ( W = 3880 l b , r e f . 3 ) , t h e Hawker P-1127 d e f l e c t e d j e t VTOL ( W = 12,500 l b ) , and t h e XC-142A t i l t - w i n g VTOL t r a n s p o r t ( W = 37,500 l b , r e f . 10). Data f o r t h e l a t t e r two were supplied by t h e manufacturer. P i l o t r a t i n g s f o r t h e v i s u a l hovering t a s k , where a v a i l a b l e , a r e shown i n p a r e n t h e s e s next t o t h e d a t a p o i n t s ; f o r t h e YROE-1, t h e r a t i n g s of t h e p r o j e c t p i l o t only a r e shown. The l a c k of v a r i a t i o n with g r o s s weight of c o n t r o l power r e q u i r e d t o o b t a i n a s a t i s f a c t o r y (P.R. = 3-1/2) r a t i n g f o r t h i s important "X" a x i s i s of i n t e r e s t . For t h e YROE-1, t h e p i l o t r a t i n g of u n s a t i s f a c t o r y f o r s e n s i t i v i t y i n roll (and a l s o i n p i t c h ) w a s given because Pilot of t o o l i t t l e s e n s i t i v i t y ( t o o much s t i c k t r a v e l , +7 i n . i n roll). r a t i n g s f o r s e n s i t i v i t y i n t h e P-1127 and f o r t h e XC-142A a r e not a v a i l a b l e . Reference 11 w a s used t o d e r i v e a p i l o t r a t i n g f o r t h e s e n s i t i v i t y of t h e X-14A i n roll; t h e s e n s i t i v i t y shown corresponds t o t h e 3-1/2 boundary f o r c o n t r o l power. Figure 4 i s another p l o t showing handling q u a l i t i e s information i n roll, w i t h some of t h e same d a t a . The " s a t i s f a c t o r y " (P.R. = 3 - l / 2 ) and "acceptable" (P.R. = 6-1/2)boundaries f o r l a t e r a l c h a r a c t e r i s t i c s axe shown as determined with t h e v a r i a b l e s t a b i l i t y X-14A ( r e f . 3 ) . The boundaries are p l o t t e d w i t h t o t a l c o n t r o l power as t h e a b s c i s s a and r a t e damping ( t h e r e c i p r o c a l of t h e t i m e c o n s t a n t ) as t h e o r d i n a t e . Superimposed i s a p o i n t showing t h e charact e r i s t i c s of t h e YROE-1 as determined by t h e s u b j e c t t e s t s ; it i s seen t o poss e s s , w i t h a p i l o t r a t i n g of 3, approximately t h e same c o n t r o l power and damping i n roll as w a s r e q u i r e d by t h e X-14A f o r a s a t i s f a c t o r y p i l o t r a t i n g . The values shown f o r t h e P-1127 correspond t o t h e c o n f i g u r a t i o n flown by a NASA p i l o t when t h e r a t i n g of 3 - l / 2 w a s assigned. The v a l u e s f o r t h e X C - 1 4 u l are f o r t h e unaugmented c o n f i g u r a t i o n and a r e e s t i m a t e s only.

Longitudinal C h a r a c t e r i s t i c s Figures 5 and 6 show t h e handling q u a l i t i e s i n p i t c h . It can be seen of 2-3) p o s s e s s e s much higher values of c o n t r o l power and damping about t h e Y a x i s t h a n were necessary f o r s a t i s f a c t o r y This combination (P.R. = 3-l/2) c h a r a c t e r i s t i c s i n t h e X-14A or t h e P-1127. of c o n t r o l power and damping w a s t o o high t o be evaluated i n t h e X-14A, b u t it i s s i g n i f i c a n t t h a t t h e p i l o t r a t i n g i n d i c a t e s l i t t l e improvement over t h e r a t i n g s obtained a t t h e lower l e v e l s of c o n t r o l power and damping along t h e 3.5 boundary of r e f e r e n c e 3. A s i n t h e l a t e r a l case, t h e l o n g i t u d i n a l c o n t r o l s e n s i t i v i t y w a s r a t e d a t 5 because of t h e l a r g e (+_8i n . ) s t i c k t r a v e l . The v a l u e s shown f o r t h e XC-142A a r e e s t i m a t e s f o r t h e unaugmented c o n f i g u r a t i o n . t h a t t h e YROE-1 ( w i t h a P.R.

Directional Characteristics Because of t h e unusual circumstances involved, no comparison p l o t s a r e shown f o r t h e d i r e c t i o n a l c h a r a c t e r i s t i c s . Too much c o n t r o l power

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(approximately 6 r a d i a n s / s e c 2 i n hover near sea l e v e l ) i s a v a i l a b l e t o t h e r i g h t ( a i d i n g r o t o r t o r q u e ) along w i t h a n extremely h i g h s e n s i t i v i t y (approximately 3 radians/sec2/in. corresponding t o 2 i n . p e d a l t r a v e l ) , which were given p i l o t r a t i n g s of 6 and 7, r e s p e c t i v e l y . The p i l o t must be h i g h l y compet e n t t o f l y t h e v e h i c l e s u c c e s s f u l l y because of t h i s high s e n s i t i v i t y and c o n t r o l power i n yaw. I n t h e opposite d i r e c t i o n ( t o t h e l e f t , countering r o t o r t o r q u e ) no a c c u r a t e measurements could be t a k e n s i n c e c o n t r o l power i s marginal and v a r i e s considerably with f l i g h t c o n d i t i o n as a r e s u l t of t h e varying power i n p u t t o t h e r o t o r accompanied by t h e varying t a i l r o t o r thrust r e q u i r e d and a v a i l a b l e ( i n r e f . 8, f i g . 2, it i s shown t h a t , f o r d e n s i t y a l t i t u d e s i n excess of approximately 3000 f t , i n s u f f i c i e n t d i r e c t i o n a l c o n t r o l e x i s t s t o counteract r o t o r torque).

PILOT COMMENTS

The p i l o t r a t i n g s of c o n t r o l power, s e n s i t i v i t y , and damping provided i n t h i s r e p o r t a r e based on t h e v e h i c l e c h a r a c t e r i s t i c s when hovering and maneuvering a t l o w speeds i n a r e l a t i v e l y confined a r e a . Lateral-control power i s not t h e same f o r l e f t and r i g h t i n p u t s , and r o l l - p i t c h c r o s s coupling e x i s t s f o r abrupt c o n t r o l displacements. P i t c h and r o l l c y c l i c c o n t r o l displacements a r e excessive and t h e low c o n t r o l s e n s i t i v i t y c o n t r i b u t e s t o a f e e l i n g of s l u g g i s h p i t c h and roll response, It a l s o f e e l s as though t h e r e i s a delay i n t h e c o n t r o l response from t h e time a s t e p i n p u t i s a p p l i e d t o t h e time t h e response i s f e l t . F u l l l a t e r a l c o n t r o l w a s o f t e n used i n roll r e v e r s a l maneuvers about t h e hover condition; however, p r e c i s i o n hovering over a spot w a s accomplished wit'n very s m a l l l a t e r a l control inputs.

Longitudinal c o n t r o l power w a s never l i m i t i n g i n any maneuver. F u l l c o n t r o l w a s used for t h e most abrupt quick s t o p s , b u t , as w a s noted f o r t h e l a t e r a l c o n t r o l , t h e r e w a s a l a g i n t h e response of t h e h e l i c o p t e r t o abrupt c o n t r o l i n p u t s . These e f f e c t s , which a r e s i m i l a r t o those of t h e l a r g e r H i l l e r 12E, a r e r e p o r t e d l y due t o t h e c h a r a c t e r i s t i c s of t h e servo-paddler o t o r c y c l i c - c o n t r o l system. The p i t c h c y c l i c - c o n t r o l displacement i s uncomf o r t a b l y l a r g e , p a r t i c u l a r l y f o r an overhead c y c l i c s t i c k . There w a s n o o b j e c t i o n a b l e f r i c t i o n i n t h e c y c l i c c o n t r o l and t h e f o r c e s were very d e s i r a b l e . Adequate c o n t r o l c e n t e r i n g was a v a i l a b l e , and t h e r o t o r feedback through t h e c y c l i c s t i c k w a s only n o t i c e d when abrupt c o n t r o l i n p u t s were used. P i t c h and roll damping appeared h i g h and considerable s t a b i l i t y i n t e r m s of a roll o r p i t c h r e s t o r i n g moment as a f u n c t i o n of forward or sideward speed was present.

Yaw c o n t r o l power during hovering w a s high t o t h e r i g h t b u t j u s t adequate t o t h e l e f t a t normal rpm. It w a s easy t o l o s e a l l d i r e c t i o n a l c o n t r o l power t o t h e l e f t i f t h e r o t o r rpm w a s allowed t o decay t o t h e lower r o t o r speed normal o p e r a t i n g l i m i t . Yaw c o n t r o l w a s t o o s e n s i t i v e i n normal hover and w a s considered t o be dangerous for g e n e r a l use because of t h e rocker-plate t y p e

of rudder p e d a l s and t h e very high p e d a l s e n s i t i v i t y , Yaw r a t e damping appeared t o be high enough and usable yaw r a t e s were not l i m i t e d by t h e rate damping or c o n t r o l power a t h i g h r o t o r rpm.

I n g e n e r a l , t h e r e w a s a tendency t o operate t h i s s m a l l h e l i c o p t e r i n a much t i g h t e r p a t t e r n t h a n even t h e UH-12E ( t h r e e p l a c e , 2800 l b g r o s s w t ) h e l i c o p t e r . T r a n s i t i o n s t o and from a hover were easily done a t high rates and t h e s m a l l s i z e of t h e h e l i c o p t e r minimized t h e judgment needed t o keep a s a f e d i s t a n c e from o b s t a c l e s . Operating and observing t h i s small h e l i c o p t e r f l y i n confined areas i n d i c a t e s t h a t it w a s being flown d i f f e r e n t l y t h a n a h e l i c o p t e r of even 2 8 0 0 - p o ~ dg r o s s weight. Turns and t r a n s i t i o n s t o and from hover were done much quicker t h a n i s normally done w i t h t h e l a r g e r h e l i c o p t e r s . The c y c l i c - c o n t r o l power and rate damping d i d not l i m i t t h e maneuverability of t h e YROE-1 i n and about t h e v i s u a l hover condition. The high yaw c o n t r o l sens i t i v i t y r e q u i r e d more t h a n normal p i l o t a t t e n t i o n and c o n s i d e r a b l e familiari z a t i o n time. CONCLUDING REMEiRKs

The m o s t s i g n i f i c a n t d a t a obtained i s t h a t r e p r e s e n t i n g t h e l a t e r a l c h a r a c t e r i s t i c s . This i n d i c a t e s t h a t approximately t h e same l a t e r a l c o n t r o l power i s r e q u i r e d f o r t h i s v e h i c l e as f o r t h o s e of much h i g h e r g r o s s weights t o achieve a s a t i s f a c t o r y p i l o t r a t i n g . The i n d i c a t i o n would seem t o be t h a t minimum c o n t r o l power requirements should be based p r i m a r i l y on t h e t a s k t o be performed r a t h e r t h a n on t h e g r o s s weight o r s i z e , as such. The d a t a obtained about t h e o t h e r two axes i s l e s s conclusive. Appare n t l y , t h e high c o n t r o l power a v a i l a b l e l o n g i t u d i n a l l y i s i n e f f e c t i v e because of t h e l a r g e s t i c k movements necessary w i t h consequent low s e n s i t i v i t y . D i r e c t i o n a l l y , t h e low c o n t r o l power i n t h e d i r e c t i o n opposing r o t o r torque and high c o n t r o l power i n t h e opposite d i r e c t i o n , combined w i t h extremely high c o n t r o l s e n s i t i v i t y , a r e e s s e n t i a l l y p e c u l i a r t o t h i s v e h i c l e and make t h e r e s u l t s i n a p p l i c a b l e i n any g e n e r a l sense.

It i s t o be noted t h a t undue emphasis should not be p l a c e d on making comparisons of t o t a l c o n t r o l power requirements between d i s s i m i l a r t y p e s of VTOL v e h i c l e s ( i . e . , h e l i c o p t e r , d e f l e c t e d j e t , tilt wing, e t c . ) , because of i n h e r e n t d i f f e r e n c e s i n s e l f - d i s t u r b i n g c h a r a c t e r i s t i c s , ground e f f e c t s , g u s t s e n s i t i v i t y , t r i m requirements, e t c . The comparisons made here a r e p r e s e n t e d p r i m a r i l y t o provide a convenient c a t a l o g i n g of a v a i l a b l e d a t a on VTOL airc r a f t covering a wide range of g r o s s weights and t o p o i n t out t h a t no g r o s s t r e n d of varying c o n t r o l power requirements with i n c r e a s i n g weight i s obvious. Ames Research Center National Aeronautics and Space Administration Moffett F i e l d , C a l i f . , March 16, 1965

REFERENCES

1. Anderson, S e t h B.: V/STOL A i r c r a f t .

An Examination of Handling Q u a l i t i e s C r i t e r i a f o r NASA TN D-331, 1960.

Anon. : Recommendations f o r V/STOL Handling Qualities. o c t . 1962.

R o l l s , Stewart L.; and Drinkwater, Fred J., 111: A F l i g h t Determination of t h e A t t i t u d e Control Power and Damping Requirements f o r a Visual Hovering Task i n t h e Variable S t a b i l i t y and Control X-14A Research Vehicle. NASA TN D-1328, 1962.

Anon.: D e t a i l S p e c i f i c a t i o n s f o r Model YROE-1 Rotorcycle. NAVORD Rep. SD-5l.B (Aer-AC-0411, June 23, 1959, r e v . Oct. 1960, H i l l e r A i r c r a f t Cory.).

H a l l , F. : C h a r a c t e r i s t i c s and Performance Report. H i l l e r A i r c r a f t Corp., May 4, 1960.

Anon.: A i r c r a f t and Engine Performance and S t a b i l i t y and Control T r i a l s of t h e Model YROE-1 Rotorcycle. Rep. 1, P r o j e c t TED PTR F&-42102.2, FT 23-390, Naval A i r Test Center, Patuxent River, Md. , Oct. 13, 1960.

AGARD Rep. 408,

Eng. Rep. 60-46,

C. B.; and Segner, D. R . : Contractor's Struct u r a l and Aerodynamic Demonstration of Model YROE-1 Rotorcycle. Rep. 1, F i n a l Report, P r o j e c t TED PTR AC-42102.1, FT 36-556, Naval A i r T e s t Center, Patuxent River, Md., Dee. 28, 1959.

7 . Taylor, F. W.; Hamilton,

Creer, Brent Y.; Stewart, John D.; Merrick, Robert B.; and Drinkwater, Fred J., 111: A P i l o t Opinion Study of L a t e r a l Control Requirements f o r Fighter-Type A i r c r a f t , Appen. A. NASA MEMO 1-29-59A, 1959.

Cooper, George E . : Engr. Rev., v o l .

Understanding and I n t e r p r e t i n g P i l o t Opinion.

16, no. 3, March 1957, pp. 47-51, 56.

10. S h i e l d s , M. E. : Estimated F l y i n g Q u a l i t i e s XC-142A V/STOL A s s a u l t Transport. LTV Rep. 2-53310/4R939, LTV Vought Aeronautics Div., May 22, 1964. 11. R o l l s , Stewart L.; Drinkwater, Fred J., 111; and I n n i s , Robert C . : E f f e c t s of L a t e r a l Control C h a r a c t e r i s t i c s on Hovering a J e t L i f t VTOL A i r c r a f t . NASA TN D-2701, 1965.

Aero.

TAB= I.- SUMMARY OF THE PERTINENT PARAIVlETERS DETERMINED Pilot ratings

Control power, -radians/sec2

A/C

Mode

Damping, -1/T = l / s e c

Flight AGARD test value ' ( r e f . 2)

1.7

Sensitivity, -radians/secZ/in.

-L

^_^^

I '

Flight value

value

3.9

0.24

2.0 YROE-1 Longitudinal/ (-Pitch) '

2.4

1.3

4 '

, 4

Directional

i2-1/2

( - I z~ 80)

.11

-25

X-14A (minimal s a t i s f a c t o r y)

E ( t o o low]

(3-1/2)

t o r que 1

X- 1 4 A I

.25

( -Yaw)

spec. ( r e f . 2)

'e (-In'? 1170)

satisfactory)

'ens'tivity

power

YROE- 1 T

, Control

high)

-5

1.0

2.4

("Izz 3 2920)

.17

.23

(3-1/2)

(n.a.>

TABU 11.- PIL9T OPINION RATING SCHEDULE

~~~

rating

Unsatisfactory

operat i o n

No operation

?ailwe

I I

1Unsatisfactory

8 9

of a s t a b i l i t y augmenter

Description E x c e l l e n t , i n c l u d e s optimum Good, p l e a s a n t t o f l y S a t i s f a c t o r y , b u t w i t h some m i l d l y unpleasant c h a r a c t e r i s t i c s Acceptable, b u t w i t h unpleasant characteristics Unacceptable f o r normal o p e r a t i o n Acceptable f o r emergency c o n d i t i o n only* Unacceptable even f o r emergency condition* Unacceptable - dangerous Unacceptable- unc o n t r o l l a bl e

Primary mission a cc omp 1ished

Can b e landed

Yes Yes

Yes

Doubtful

Yes Yes

Doubtful

Yes

Figure 1.- YROE-1 Rotorcycle in hovering flight. \D

A-31028

Figure 2.- Three-view drawing of test vehicle.

@ Full deflection (- Total control power)

I I

One inch ( w Control sensitivity)

i ti i IROE-I

1 ~ x - 1 4 ~

P.R.- 4

RR .N 5

(Too low)

Io2

8 IO3

8 lo4

Gross weight, W, Ib

Figure 3

P P

.- Lateral control characteristics ( -

visual hovering task).

8 1

-4

-3

-2

-I

Lateral

Figure

2 control

3 power,

radians/sec

4.- Lateral handling characteristics.

I I I

E One inch

0 a, UJ

> C

(-Control

sensitivity)

0 Full deflection (- Total control power)

:8 C

.-0

. I -

Ea, FYROE-I'

Z3 P.R.-

(Too low) I

IO2

IO3

8 IO'

Gross weight, W , Ib Figure

5.-

Longitudinal c o n t r o l c h a r a c t e r i s t i c s ( - v i s u a l hovering t a s k ) .

8 1

- 2.4

I fROE-I

I I (P.R.m 2 - 3 ) -

- 2.0

- 1.6

- 1.2

m P-1127 ( P . R . - 3 2 ) U7

(Est. d a m p i n g ) I

- X-14A I

(Ref. 3 ) I

Unaug.

@ XC-142A (Est.)

.4 Longitudinal

(P.R.I..

I.2

.8 control

power,

2.o

I .6 radians/sec

Figure 6.- Longitudinal handling characteristics.

NASA-Langley, 1965

A-857

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