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Patented J a n . 2 6 , _ 1 9 5 4 I i ' ~ i
UNITED STATE P A T E N T2,667,351
2,667,351
O F F I C E "NONLIFTING TOWEDTARGET GLIDER
Marion 0 . McKinney, J r . , and John P . C a m p b e l l
,Hampton, Va. ' .
A p p l i c a t i o n March 8 , 1 9 5 1 , S e r i a l N o . 2 1
8 , 0 5 82 Claims. ( 0 1 . 2 7 3-1053)
s e c . 26( G r a n t e d under T i t l e 3 5 % ) U . S . Code (
1 9 5 2 ) ,1This i n v e n t i o n r e l a t e s t o
airplane-shaped towt a r g e t s f o r u se in simulation o f a i r
combat conditions. 'Tow a r g e t s have been i n common u se 1 n
theform o f towed g l i d e r s provided with c o n v e n t i o n a
lw i n g s . T h e s e g l i d e r s , w h i l e s a t i s f a c t
o r y f o r l o w e rs p e e d u s e s have proven p r a c t i c a
l l y i m p o s s i b l e f o ru s e a t h i g h e r s p e e d s
due t o g e n e r a l i n s t a b i l i t y an dl a c k o f
strength a t t h e s e s p e e d s . I f the g l i d e r i s
of l i g h t construction the high s p eed loads pro- -duce d i
s t o r t i o n o f t h e a i r f r a m e which i n turnc a u s e s
e x c e s s i v e a c c e l e r a t i o n s an d trim c h a n g e s
.I f o f heavy construction t o withstand a i r l o a d s ,trouble
w i l l be experienced i n unstable l a t e r a l o s - 1c i l l a
t i o n s du e t o the high mass an d m o m e n t s o finertia. _
_T he p r e s e n t i n v e n t i o n meets the d l f ? c u l t i e
smentioned by removing the l i f t function from thew i n g s , as
i t has been determined that there i s n on e e d f o r l i f t i n
a t ow g l i d e r , an d employing thewing o n l y t o make the t
a r g e t l o o k l i k e an a i r p l a n e .T he o b j e c t s o
f the i n v e n t i o n t h e r e f o r e i n c l u d ep r o v i s
i o n o f g l i d e r wings having n o n l i f t a t t r ib u t e s
, s e r v i n g primarily a s a m ea n s o f providingthe t a r g e
t with the shape o f an a i r p l a n e , an dhaving a con?guration
e ? e c t i v e t o reduce draga t h i g h s p e e d s ,A u r t h e
r o b j e c t i s t o provide a g l i d e r s u i t a b l e
f o r t ow t a r g e t u s e s which i s s t a b l e a t a i r p
l a n es p e e d s i n t h e neighborhood o f 5 0 0 m i l e s p e r
h o u r ,an d which a t the s a m e time simulates a i r p l a n
econstruction. Other objects w i l l appear on co ns i d e r a t i
o n o f the f o l l o w i n g d e s c r i p t i o n o f a preferred
e m b o d i m e n t of the invention taken in conj u n c t i o n
with the drawings i n which
F i g . l i s a perspective View o f a g l i d e r withwings o f
c o n v e n t i o n a l form p i v o t e d a x i a l l y aheado f t
h e aerodynamic c e n t e r ;F i g . 2 i s a view of a m o d i ? e
d non-lift w i n gf o r m ;F i g . 3 i s a view o f the g l i d e r
wing o f F i g . 2 witha t r a i l i n g ?ap;F i g . 4 i s a view o
f the g l i d e r wings o f F i g . 3 with
a swept back c o n s t r u c t i o n .In F i g . 1 the t ow t a
r g e t form i s that o f a co n
v e n t i o n a l g l i d e r l 0 b e a r i n g t h e u s u a l
f u s e l a g e I Ian d t a i l ?n s i n c l u d i n g v e r t i c
a l ?n l 2 an d s t a b il i z e r | 3 .T he wings l 5 i n c l u d
e r i g h t an d l e f t s e c t i o n s l 6an d I l . Each o f t h
e s e s e c t i o n s i s p i v o t a l l ym o u n t e d on a rod
support [ 8 extending l a t e r a l l yfrom t h e f u s e l a g e
and i n l i n e with each o t h e r andi s f r e e t o p i v o t
independently o r t o g e t h e r aboutt h e spanwise a x i s o f t
h e wing s e c t i o n . T he p i v o trod i s p l a c e d ahead o
f t h e areodynamic c e n t e r
25
30
35
45
50
55
alignment w i t h thewind; a l s o2
o f t h e Wing t o i n s u r e a s t r o n g tendency o f
wingthe w i n g i s m a s sbalanced t o a v o i d f l u t t e n Thu
s t h e l i f t f u n c t i o no f t h e wings i s removed,
dependence f o r s t a b i l i t yb e i n g p l a c e d p r i m a r
i l y on t h e t o w l i n e an d g l i d e r
t a i l s with such s t a b i l i t y f a c t o r s a s the
modi? edwings a l f o r d .By t h e d e s c r i b e d modi?cation o
f t h e Wing s t r u ct u r e g l i d e r s p e e d s i n the
neighborhood o f 5 0 0
m i l e s p e r hour become f e a s i b l e without substant i a
l changes i n t h e o v e r a l l c o n s t r u c t i o n form
andweight a s used i n the conventional g l i d e r . A tt h e s e
h i g h s p e e d s t h e r e i s s a t i s f a c t o r y s t a b i
l i t ywith marked r e d u c t i o n i n s e n s i t i v i t y t o
trimc h a n g e s and o t h e r m o d i f y i n g c o n d i t i o n
s .
I t i s p o i n t e d o u t t h a t t h e wings a r e f r e e l
y p i vo t e d each e n t i r e l y i n d e p e n d e n t l y o f t
h e o t h e r , s ot h a t e a c h wing a u t o m a t i c a l l y a
d j u s t s i t s e l f t o t h ewind i n c i d e n c e , o r t h e
wings may be connectedt o g e t h e r f o r s i m u l t a n e o u s
o p e r a t i o n . A l s o , a sd e m o n s t r a t e d by t e s t
s , t h e t o w l i n e p r o v i d e s a d eq u a t e b a n k s t
a b i l i z a t i o n s where t h e g l i d e r hasz e r o l i f t
, s i n c e t h e g l i d e r t e n d s t o t r a i l below t h
etowing a i r p l a n e . I t i s , o f c o u r s e , n e c e s s a
r y t h a tt h e t o w l i n e b e a t t a c h e d t o t h e g l i
d e r ahead o f an dabove the g l i d e r c e n t e r o f g r a v i
t y , a value o f onet e n t h span a b o v e , an d o n e - h a l
f span ahead o f ,the c e n t e r o f g r a v i t y , w i t h a ?ve
d e g r e e t o w l i n ea n g l e , g i v i n g s a t i s f a c t
o r y r e s u l t s .In F i g . 2 a modi? ed form o f wing 2 0 i s
shownwith t h e a i r f o i l s e c t i o n s 2 | an d 2 2 c i r c
u l a r i n
s e c t i o n : i . e . rods or c y l i n d e r s . Th e s e a i
r f o i l s areadequate f o r the t ow function bu t are de?cienti
n v i s i b i l i t y f o r t a r g e t p u r p o s e s , a d e f e
c t whichmay be r e c t i ? e d by hinging a panel o r ?aps 3 0and
3 | t o t h e t r a i l i n g edge o f the a i r f o i l s e c t i
o n s2 ! and 2 2 r e s p e c t i v e l y , a s i n d i c a t e d i
n F i g . 3 , s ot h a t the ?aps t r a i l f r e e l y i n t h e w
i n d . T he c r i t ic a l Mach u m b e r o f a c i r c u l a r a
i r f o i l s e c t i o n wingi s r e l a t i v e l y l o w . A c c
o r d i n g l y , i n o r d e r t o a v o i du n d u e drag a t
high s p e e d s , i t may be d e s i r a b l et o swee p back t h
e wing a s shown by Wings 4 0 an d4 | i n F i g . 4 .
In a l l wing forms a s shown i n F i g s . 1 , 2 an d 3 ,the
nose o f the wing a i r f o i l i s symmetrically co ntoured s o
that the pro?les on both s i d e s o f thenose t i p a r e s i m i
l a r bu t r e v e r s e d . I t i s pointedo u t , a l s o , t h a
t i n a l l m o d i ? c a t i o n s t h e p i t c h i n gmoment r ,
a s otherwise s t a t e d , the l i f t i s z e r o .
Other modi?cations o f t h e i n v e n t i o n may beapparent t
o t h o s e s k i l l e d i n t h e a r t an d hence n ol i m i t a
t i o n i s i n t e n d e d by t h e s p e c i ? c d i s c l o s u
r eo t h e r than may e r e q u i r e d by t h e s c o p e o f c l
a i m sh e r e t o a p p e n d e d ,The i n v e n t i o n d e s c r
i b e d h e r e i n m ay be m a n u .
8/22/2019 Tow Target Glider (1951)
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f a c t u r e d an d used by o r f o r the Government o ft h e U
n i t e d S t a t e s o f A m e r i c a f o r g o v e r n m e n t a
lpurposes without t h e payment o f an y r o y a l t i e sthereon
or therefor.What s claimed s :1 . A t o w - g l i d e r comprising
a f u s e l a g e , guideV?ns i n c l u d i n g s t a b i l i z e r
s a t the t a i l end o f s a i df u s e l a g e , = a l i n e d r
o d l i k e elements o f uni-formcirc u l a r c r o s s - s e c t i
o n s e c u r e d t o an d extendingt r a n s v e r s e l y from s
a i d f u s e l a g e . . a , p a i r . o f . w i n gs i m u l a t
i n g ?aps each p i v o t e d f r e e l y on s a i d e l e
m e n t s a t a r e s p e c t i v e one o f 1 1 9 9 1 3 1 1 s i
d e s of saidfuselage o n a l i n e intermediate the nose and-weare
d g e s o f t h e f l a p an d d i s p l a c e d toward the?ap
2 , 6 6 7 , 3 5 1
nose from the aerodynamic "?ap ' c e n ' t e r "whereby 1 5a z e
r o l i f t c h a r a c t e r i s t i c i s a t t a i n e d , . t h
e ?ap shaving p r o ? l e s s y m m e t r i c a l l y c o n t o u r
e d on boths i d e s o f the f u s e l a g e .2 . A t o w - g l i d
e r comprising a f u s e l a g e , g u i d e? ns i n c l u d i n g
s t a b i l i z e r s a t the t a i l en d o f s a i d 2 0f u s e l
a g e , a l i n e d support elements : s e c u r e d to an
dextending t r a n s v e r s e l y from said i f u s e l a g e on"
opp o s i t e s i d e s t h e r e o f , a p a i r of ' v i i n g s
i m u l a t i n g
4 .?aps each p i v o t e d f r e e l y on one o f s a i d
elementson a l i n e intermediate the nose an d r e a r edge o ft h
e ?ap and d i s p l a c e d toward t h e ?ap nose fromthe
aerodynamic ? ap center whereby a z e r o l i f tc h a r a c t e r
i s t i c i s a t t a i n e d , t h e f l a p s having p r o? l e s
symmetrically contoured on both s i d e s o f t h ef u s e l a g e
. M A R I O N O . MCKINNEY, R .JOHN P . CAMPBELL.
R e f e r e n c e s ' C i t d i n t h e ? l e o f t h i s p a t
e n tUNITEDSTATES PATENTS
Number Name Date4513-;016 L o v e _____________ _ F eb. 16 , 1 9
2 61, 805, 927 A l d rich __________ __ May 6, 1 9 3 11,844,448
Sramek ___________ __ Feb. 9 , 1 93 21 , 8 5 - 7 ? 0 1 l uVa-rren
____________ May 0 , 1 93 22,238,875 Manson __________ __ A pr . 1
5 , 1 9 4 12 , 2 98 , 42 5 Sha?er _ ' _ _ _ . ______ _- Oct, 1 3 ,
1 9 4 21 2 . 4 4 0 3 7 3 ? Ca-wein ~___________. .May , 4 , . 1 9 4
825.28268 - D i c k i n s , o n _ s _ - _ . _ _ _ _ _ . Q c t . 31,
19 5 9
