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AD NUMBER

LIMITATION CHANGESTO:

FROM:

AUTHORITY

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Approved for public release; distribution isunlimited.

Distribution: Further dissemination only asdirected by MOL project Office, (SAFSL-5B0, LosAngeles, CA 90045, APR 1969, or higher DoDauthority.

ADEC USAF ltr, 12 Oct 1972

AEDC-TR-69-75 UNCLASS~RED

DOC NUM SER CN UNClO945-PDC A 1

lllIllllllll, IIllllllllllllilllll, I'iilll, llllll, llllillllllll, INVESTIGATION AT HIGH ALTITUDES

OF ROCKET EXHAUST PLUME SYMMETRY AND INTERACTION WITH A PLATE WITH A SCALED MOL THRUSTER

D. W. Hill, Jr.

ARO, Inc.

April 1969

This document may be further distributed by any holder only with specific prior approval of MOL Project Office (SA-"--FSL.SB), AF Unit Post Office, Los Angeles, California 90045.

AEROSPACE ENVIRONMENTAl. FACILITY

ARNOLD ENGINEERING DEVELOPMENT CENTER

AIR FORCE SYSTEMS COMMAND

ARNOLD AIR FORCE STATION, TENNESSEE

UNCLASSaFaE~

OTIC£S When U. S. Government rlr,twing~ ,~perlfieati(.n.-,. or , I he r da ta ale used for any pu rpose other than a <]efizHtelx le ]a ted Govermnent l),'.",e.r<'m(;nt .pL.ration. the Gov(.=xL:rlq..".l ther(+hy znear.q no r e s p o n s i b t l i t y nor any obl iga t ion v.ha).qoever, and tit(. fac.t that t'.qe (;o~,~.rnment may have formulated, fu rn i shed , or in an,, way supp l i ed the s a i d .Irawzags. spc:c i f i c a t i o . s , or other da ta . i¢. not to he r ega rded by impl ica t ion or o therw.s . - , or in any r.ann..'r hect~c, nng the holdcz o, any .t|v-.r person or corpora t ion , or c o n v e y i n g any right-, or pe rmi s s ion to maz.::fa, ' t .r . : . ..s~.. ox "..ell m:y p:ztf,nt,.,I t:,ve¢:t:on tha t n.ay in any way be r e l a t e d the re to .

I

I|el'or~.nces Io nam,,d eommercnal produc ls in Ihns r(,port ar.- not to be cons idered in any s~=nse as all J *=.ndor,.,ement of the pr .du, : t bv the Uni ted S1ate.~ ,Xl: F err.. or th(; ( ;overnment . I

AEDC.T R-69.75

I N V E S T I G A T I O N A T HIGH A L T I T U D E S

O F R O C K E T E X H A U S T P L U M E S Y M M E T R Y

A N D I N T E R A C T I O N W I T H A P L A T E

V~qTH A S C A L E D M O L T H R U S T E R

D. W. H i l l , J r .

A R O , I n c .

This document may be further distributed by any holder only with specific prior approval of MOL Project Office (SAFSL-SB), AF Unit Post Office, Los Angeles, California 90045.

A EDC.T R-69-75

FOREWORD

The work r epo r t ed h e r e i n was p e r f o r m e d at the r eques t of Space and M i s s i l e S y s t e m s Organ iza t ion (SAMSO), Ai r F o r c e S y s t e m s Com- m a n d ( A F S C ) , under P r o g r a m E lemen t 35121F/632A.

The rocke t engine and s i m u l a t e d veh ic le sk in t e s t ed were des igned and fab r i ca ted by Marqua rd t Corpora t ion and McDonnel l Douglas Corpora t ion , M i s s i l e s and Space S y s t e m s Divis ion (MSSD), r e s p e c t i v e l y .

The r e s u l t s of the t e s t s p r e s e n t e d were obtained by ARO, Inc. (a s u b s i d i a r y of Sverd rup & P a r c e l and A s s o c i a t e s , Inc . ) , con t r ac t ope ra to r of the Arnold Eng inee r ing Development Cen t e r (AEDC), AFSC, Arnold Ai r F o r c e Stat ion, T e n n e s s e e , under Con t rac t F40600-69-C-0001 . The t e s t s were conducted f rom May through D e c e m b e r 21, 1968, under ARO P r o j e c t No. SB0721, and the m a n u s c r i p t was submi t t ed for pub l ica - t ion on F e b r u a r y 26, 1969.

In fo rma t ion in th is r epor t is embargoed under the Depar tmen t of State In t e rna t i ona l Tra f f i c in A r m s Regula t ions . This r epo r t may be r e l e a s e d to fo re ign g o v e r n m e n t s by depa r tmen t s or agenc ie s of the U. S. Government subjec t to approva l of the MOL P r o j e c t Office (SAFSL-5B), or h ighe r au tho r i t y within the Depar tmen t of the A i r F o r c e . P r i v a t e indiv iduals or f i r m s r e q u i r e a Depar tmen t of State export l i c ense .

Th i s t e chn i ca l r epo r t has been rev iewed and is approved.

Pau l L. L a n d r y Major, USAF AF Rep re sen t a t i ve , D i r e c t o r a t e of Tes t

AEF

Roy R. Croy, J r . Colonel, USAF D i r e c t o r of Tes t

i i

A EDC.T R-69.75

ABSTRACT

A 1 - 1 b - t h r u s t r o c k e t e n g i n e w a s t e s t e d to d e t e r m i n e p l u m e s y m m e t r y and M a c h n u m b e r c o n t o u r s at 400, 000 - f t a l t i t u d e . T o t a l p r e s s u r e s u r - v e y s w e r e m a d e w i t h and w i t h o u t a f la t p l a t e in t he p l u m e . T h e t e s t s w i t h o u t t h e p l a t e i n d i c a t e d t h e p l u m e w a s s y m m e t r i c a l , and m e a s u r e d r e s u l t s c o m p a r e d w e l l w i t h c o m p u t e d v a l u e s . In t e s t s w i t h t h e p l a t e , t h e s h o c k i n t e r a c t i o n and b o u n d a r y - l a y e r b u i l d u p on t h e p l a t e w e r e m e a s u r e d .

This document may be further distributed by any holder only with specific prior approval of MOL Project Office (SAFSL-SB), AF Unit Post Office, Los Angeles, California 90045.

iii

AEDC-TR.69.75

CONTENTS

A B S T R A C T . . . . . . . . . . . . . . . . .

N O M E N C L A T U R E . . . . . . . . . . . . . . . . . .

I . I N T R O D U C T I O N . . . . . . . . . . . . . . . . . . .

I I . T E S T F A C I L I T Y . . . . . . . . . . . . . . . . . .

I I I . T E S T A R T I C L E S . . . . . . . . . . . . . . . . . .

I V . T E S T I N S T R U M E N T A T I O N . . . . . . . . . . . . . . V. P R O C E D U R E . . . . . . . . . . . . . . . . . . . .

V I . R E S U L T S A N D D I S C U S S I O N . . . . . . . . . . . . .

V I I . C O N C L U S I O N S . . . . . . . . . . . . . . . . . . .

R E F E R E N C E S . . . . . . . . . . . . . . . . . . .

i i i

v i

1

I 2 4

4 5

7

7

APPENDIXES

I . I L L U S T R A T I O N S

F i g u r e

1.

2.

3.

4 .

5.

6.

7.

8.

9.

10.

I i .

12.

13.

14.

A e r o s p a c e R e s e a r c h C h a m b e r (8V) . . . . . . . . . .

O n e - P o u n d - T h r u s t E n g i n e a n d V a l v e s . . . . . . .

P r o p e l l a n t S y s t e m . . . . . . . . . . . . . . . . .

P i t o t P r o b e R a k e w i t h o u t P l a t e . . . . . . . . . . .

P i t o t P r o b e R a k e w i t h P l a t e . . . . . . . . . .

T e s t I n s t a l l a t i o n - T h r u s t e r , P l a t e , a n d P i t o t R a k e

T e s t D a t a S y s t e m . . . . . . . . . . . . . . . . .

E n g i n e P r e s s u r e a n d F l o w R a t e s . . . . . . . . . . .

P r e d i c t e d A R C 8V C h a m b e r P e r f o r m a n c e . . . . . .

A R C 8V C h a m b e r P r e s s u r e v e r s u s E n g i n e F i r i n g T i m e . . . . . . . . . . . . . . . . . . . . .

T o t a l P r e s s u r e P r o f i l e in P l u m e a t x = 1 9 . 7 5 in . . . .

T o t a l P r e s s u r e P r o f i l e in P l u m e a t x = 3 0 . 5 in . . . . .

M a c h N u m b e r C o n t o u r s f o r 1 - 1 b - T h r u s t E n g i n e . . . .

T o t a l P r e s s u r e S u r v e y a b o v e P a n e l S u r f a c e s a t

x - 1 5 . 0 in . . . . . . . . . . . . . . . . . . . . .

I i

12

13

14

15

16

17

18

19

20

21

22

23

24

V

A E DC-T R-69-75

F i g u r e

15. T o t a l P r e s s u r e S u r v e y a b o v e P a n e l S u r f a c e s a t x = 23 .25 in . . . . . . . . . . . . . . . . . . . . .

16. I m p i n g e m e n t P a t t e r n on P l a t e . . . . . . . . . . . .

II . T A B L E

I. T e s t L o g .

Page

25

26

27

NOMENCLATURE

M

rh

O/F

P

t

x

Y

z

-y

M a c h n u m b e r

T h r u s t e r m a s s f low r a t e

O x i d i z e r - t o - f u e l r a t i o

P r e s s u r e

T i m e

A x i a l d i s t a n c e a l o n g t h r u s t e r c e n t e r l i n e

D i s t a n c e f r o m c e n t e r l i n e of t h r u s t e r

D i s t a n c e f r o m t h e s u r f a c e of p l a t e to c e n t e r l i n e of p i to t t u b e

R a t i o of s p e c i f i c h e a t s

SUBSCRIPTS

2

C

F

O

t

S t a g n a t i o n p r e s s u r e b e h i n d s h o c k

C o m b u s t i o n c h a m b e r

F u e l

O x i d i z e r

T o t a l p r e s s u r e

v i

AEDC.T R.69.75

SECTION I

INTRODUCTION

The exhaus t p l u m e s f r o m a t t i tude c o n t r o l r o c k e t eng ine s f i r e d at o r b i t a l a l t i t udes expand so that the exhaus t p r o d u c t s s t r i k e s p a c e c r a f t s u r f a c e s and e x t e r n a l l y m o u n t e d c o m p o n e n t s l o c a t e d wi th in a l a r g e e n v e l o p e ex t end ing d o w n s t r e a m f r o m the n o z z l e exi t p lane . The i m - p i n g e m e n t of the gas r e s u l t s in loca l s u r f a c e hea t ing , s u r f a c e p r e s - s u r e s , and p o s s i b l e c o n t a m i n a t i o n of s p a c e c r a f t s u r f a c e s . T h e s e e f fec t s m a y c a u s e m a l f u n c t i o n s of a p p a r a t u s m o u n t e d on or i n s i d e the s p a c e c r a f t . It is , t h e r e f o r e , i m p o r t a n t to iden t i fy and u n d e r s t a n d the cond i t ions that c a u s e t h e s e e f fec t s so that t hey m a y be p r o p e r l y con - s i d e r e d in the d e s i g n and o p e r a t i o n of the s p a c e c r a f t . T h e r e have been s e v e r a l a n a l y t i c a l p r e d i c t i o n s of exhaus t p l u m e b e h a v i o r (Refs . 1 and 2) and s o m e l i m i t e d e x p e r i m e n t a l t e s t s at h igh a l t i t ude (Refs . 1 t h r o u g h 4). T h e s e t e s t s have been l i m i t e d to s h o r t d u r a t i o n s with t r a n s i e n t a l t i t udes f r o m 400, 000 to 200, 000 ft.

The p u r p o s e of th is t e s t was to d e t e r m i n e if t h e r e was p l u m e s y m - m e t r y and to d e t e r m i n e the i n t e r a c t i o n of a 1 -1b- th rus t s c a l e d t h r u s t e r p l u m e with a flat p l a t e which s i m u l a t e d the v e h i c l e sk in . The t e s t r e - q u i r e d f i r i ng the 1 -1b - th rus t s c a l e d a t t i tude c o n t r o l t h r u s t e r con t inu - ous ly for up to 205 sec whi le m a i n t a i n i n g a 400, 000-f t a l t i tude .

SECTION II TEST FACILITY

The t e s t was conduc ted in the A e r o s p a c e R e s e a r c h C h a m b e r (ARC) (8V) of the A e r o s p a c e E n v i r o n m e n t a l F a c i l i t y . The s t a i n l e s s s t e e l c h a m b e r {Fig. 1, Append ix I) is 20 ft long and 10 ft in d i a m e t e r . The c r y o p u m p i n g s u r f a c e s and a r r a n g e m e n t s w e r e d e s i g n e d for r e m o v i n g gas p r o d u c t s f r o m r o c k e t eng ine s and low dens i t y n o z z l e s of h igh en tha lpy . The 620 ft 2 of l i q u i d - n i t r o g e n ( L N 2 ) - c o o l e d s u r f a c e s , 800 ft 2 of g a s e o u s - h e l i u m ( G H e ) - c o o l e d s u r f a c e s , and 50 ft 2 of l i q u i d - h e l i u m ( L H e ) - c o o l e d s u r f a c e s w e r e a r r a n g e d to r e m o v e 16 kw f r o m the exhaus t gas p r o d u c t s in an o p t i m u m m a n n e r .

The s k e t c h be low and Fig. 1 show the a r r a n g e m e n t of the c r y o - s u r f a c e s to pump the h igh en tha lpy exhaus t gas p r o d u c t s . The gas l e a v i n g the eng ine p a s s e s t h r o u g h the r a d i a l l y a r r a n g e d f o r w a r d GHe s u r f a c e s and i m p i n g e s on the a n n u l a r LN 2 c r y o s u r f a c e w h e r e 8 kw is r e m o v e d . The coo led gas is then e i t h e r c r y o p u m p e d by the LN 2 s u r f a c e

AEDC-T R.69.75

o r r e f l e c t e d back onto the GHe c r y o s u r f a c e w h e r e it is c o n d e n s e d . T h e r e is a to t a l GHe r e f r i g e r a t i o n c a p a c i t y of 8 kw - 7 kw fo r the f ron t GHe c r y o p u m p and the r e m a i n i n g 1 kw for the r e a r . S ince h y d r o g e n (H2) has a h igh v a p o r p r e s s u r e (10 -4 t o r r ) on 15°K GHe s u r f a c e s , L H e (4 .2°K) was u sed to r e m o v e the H 2. The H 2 and n i t r o g e n (N 2) e x h a u s t g a s e s m o v i n g a x i a l l y down the c h a m b e r i m p i n g e on the LN 2 p r e c o o l e r , w h e r e e n e r g y is r e m o v e d , and t hen a r e c r y o p u m p e d on the LHe c r y o s u r f a c e s .

/J n ioeq

f LN L i n e r , 77°K

I ! • L roo, o / -

GHe, 15 K /

J ~ -,~--LHe, 4.2°K '~'~

• LN 2 P r e c o o l e r ~ ~"

I ' \ .. i

The f ron t GHe c r y o s u r f a c e s c o n s i s t of f i f t y - two 8- by 1-ft pane l s p o s i t i o n e d in a r a d i a l a r r a y about the axis of the c h a m b e r . T h e r e a r GHe c r y o s u r f a c e is 8 ft long and 6 ft in d i a m e t e r . The supp ly of the gas to the f ron t o r r e a r GHe c r y o s u r f a c e s cou ld be d i s t r i b u t e d by e x t e r n a l l y o p e r - a t ed v a l v e s .

The LHe was m a d e in the A e r o s p a c e E n v i r o n m e n t a l F a c i l i t y . A 3 0 - 1 i t e r / h r He l i q u e f i e r in c o n j u n c t i o n wi th a 4 -kw GHe r e f r i g e r a t o r was u s e d as a p r e c o o l e r for the ga s . A 1 0 0 0 - l i t e r d e w a r l o c a t e d on top of the c h a m b e r h o u s e d a J o u l e - T h o m p s o n va lve for the f ina l s t a g e s of l i q u e f a c t i o n and s t o r a g e of LHe .

SECTION III TEST ARTICLES

3.1 1-LB-THRUST SCALED THRUSTER

The 1 - 1 b - t h r u s t M a n n e d O r b i t i n g L a b o r a t o r y (MOL) s c a l e d t h r u s t e r u s e d in the t e s t was s u p p l i e d by M c D o n n e l l D o u g l a s . The b i p r o p e l l a n t ,

AEDC-T R.69.75

m o n o m e t h y l h y d r a z i n e and n i t r i c oxide (MMH-N204) , t h r u s t e r (F ig . 2) was d e s i g n e d for both s t e a d y and pu l s ing o p e r a t i o n . The p e r f o r m a n c e of the eng ine was i n v e s t i g a t e d by M a r q u a r d t C o r p o r a t i o n p e r s o n n e l who found that the l o w e r t h r u s t l e v e l r e s u l t e d in l o w e r c o m b u s t i o n e f f i c i e n c y and pu l s ing p e r f o r m a n c e . Dur ing the f i r ing , the p r o p e l l a n t va lve s and i n j e c t o r s w e r e he ld at 60°F wi th coo l ing w a t e r .

The t h r u s t e r d e s i g n p a r a m e t e r s and p e r f o r m a n c e a r e shown be low.

T h r u s t F u e l O x i d i z e r C h a m b e r P r e s s u r e M i x t u r e Rat io Nozz l e E x p a n s i o n Rat io Nozz l e G e o m e t r y C h a m b e r T e m p e r a t u r e T h r o a t D i a m e t e r Nozz l e Exi t D i a m e t e r C o m b u s t i o n E f f i c i e n c y

1 . 0 1 b MMH ( M o n o m e t h y l h y d r a z i n e ) N 2 0 4 90 p s i 1 .65 + 1.5 40:1 C o n t o u r e d 4000°F 0. 090 in. 0. 569 in. 0. 830

Shown in Fig . 2 is the a s s e m b l e d 1-1b t h r u s t e r . It c o n s i s t s of a s i n g l e - d o u b l e t w a t e r - c o o l e d i n j e c t o r head, h igh r e s p o n s e s o l e n o i d v a lv e s , and two 5 - m i c r o n n o m i n a l f i l t e r s u p s t r e a m of each va lve . The n o z z l e and c o m b u s t i o n c h a m b e r a r e an i n t e g r a l par t , m a c h i n e d f r o m m o l y b d e n u m .

F i g u r e 3 shows the 1-1b t h r u s t e r p r o p e l l a n t s y s t e m . The s y s t e m c o n s i s t s m a i n l y of t h r e e p a r t s : the eng ine n i t r o g e n pu rge , h i g h - p o i n t b l e e d s , and p r o p e l l a n t supp ly s y s t e m . E a c h p r o p e l l a n t t ank has a c a p a c i t y of 2 l i t e r s . The p r o p e l l a n t s w e r e p r e s s u r i z e d wi th d ry n i t r o - gen. The p r o p e l l a n t l ine was 0. 180-in. -ID s t a i n l e s s s t e e l tub ing .

3.2 TEST PLATE

The t e s t p la te which was s u p p l i e d by McDonne l l Douglas C o r p o r a - t ion (NISSD) was 30 by 32 in. and 1 in. th ick . The a l l - w e l d e d h o n e y c o m b s a n d w i c h p la te was c o n s t r u c t e d f r o m s t a i n l e s s s t e e l . The faces of the p la te a r e 0 .017 in. th ick and the c o r e t h i c k n e s s is 0. 0025 in.

AEDC-TR-69.75

SECTION IV TEST INSTRUMENTATION

T h e p i t o t r a k e ( F i g s . 4, 5, a n d 6) c o n s i s t e d o f n i n e 0 . 2 5 - i n . - O D p i t o t t u b e s w h i c h w e r e 10 in . l o n g . T h e m i d d l e t u b e w a s - p o s i t i o n e d on t h e c e n t e r l i n e of t h e t h r u s t e r . T h e r e m a i n i n g e i g h t t u b e s w e r e p o s i - t i o n e d at a n g l e s r e l a t i v e to t h e t h r u s t e r a x i s . E a c h p i t o t t u b e w a s c o n - n e c t e d to a B a r a t r o n ® p r e s s u r e t r a n s d u c e r w h i c h w a s m o u n t e d on t h e r a k e . T h e r a k e w a s d e s i g n e d s o i t c o u l d be m o u n t e d in b o t h v e r t i c a l a n d h o r i z o n t a l p o s i t i o n s . T h e r a k e w a s a t t a c h e d in e i t h e r of t h e p o s i - t i o n s to a s l i d e m e c h a n i s m s o i t c o u l d be m o v e d a x i a l l y and l a t e r a l l y w i t h r e s p e c t t o t h e t h r u s t e r . T h e s l i d e m e c h a n i s m w a s m a n u a l l y o p e r - a t e d f r o m o u t s i d e t h e c h a m b e r . T h e n i n e B a r a t r o n s h a d a m a x i m u m r a n g e of 10 t o r r . T h e r e s p o n s e t i m e of t h e p r e s s u r e t r a n s d u c e r s in t h i s i n s t a l l a t i o n w a s l e s s t h a n a s e c o n d . T h e r e w a s a c o p p e r - c o n s t a n t a n t h e r m o c o u p l e m o u n t e d o n e a c h of t h e n i n e p i t o t p r o b e s . T h e y w e r e p o s i - t i o n e d 1 in . f r o m t h e l i p o f t h e p r o b e .

T h e r e w e r e f o u r V e e c o ® i o n i z a t i o n g a g e s l o c a t e d a t v a r i o u s p o s i - t i o n s in t h e c h a m b e r . O n e g a g e w a s l o c a t e d b e h i n d t h e t h r u s t e r f o r m e a s u r i n g t h e p r e s s u r e a l t i t u d e d u r i n g f i r i n g . T h e r e m a i n i n g g a g e s w e r e l o c a t e d n e a r t h e L H e c r y o p u m p in o r d e r to e v a l u a t e i t s p e r f o r m - a n c e . O n e A l p h a t r o n ® g a g e w a s i n s t a l l e d b e h i n d t h e t h r u s t e r t o m e a s - u r e p r e s s u r e s a b o v e 10 -3 t o r r .

T h e t h r u s t e r w a s i n s t r u m e n t e d w i t h t h r e e T a b e r ® 5 0 0 - p s i a p r e s s u r e t r a n s d u c e r s and t w o P o t t e r ® f l o w m e t e r s w i t h a r a n g e up to 3 g m / s e c . T h e r e s p o n s e t i m e of t h e f l o w m e t e r s i s o n e s e c o n d .

F i g u r e 7 show-s t h e d a t a s y s t e m w h i c h w a s u s e d d u r i n g t h e t e s t . T h e p i t o t p r e s s u r e s , t e m p e r a t u r e s , and e n g i n e f low r a t e s w e n t i n t o s i g n a l c o n d i t i o n i n g e q u i p m e n t , a c o m m u t a t o r , a n a l o g - t o - d i g i t a l c o n - v e r t e r , d i g i t a l t a p e , a n d t h e n to t h e c o m p u t e r a n d / o r d a t a p r i n t o u t . I n a d d i t i o n , f o r r a p i d a n a l y s i s , t h e e n g i n e p r e s s u r e s a n d f l ow r a t e s w e r e r e c o r d e d on an o s c i l l o g r a p h .

SECTION V PROCEDURE

5.1 PROPELLANT SYSTEM PREPARATION

T h e p r o p e l l a n t s w e r e s p e c i a l l y f i l t e r e d u n t i l t h e y m e t t h e c l e a n l i - n e s s l e v e l s s p e c i f i e d . P a r t i c l e c o u n t s w e r e c h e c k e d b e f o r e t h e p r o p e l l a n t s

4

A E DC.T R.69.75

w e r e l o a d e d into the s y s t e m to e n s u r e tha t the s p e c i f i e d p r o p e l l a n t clean- liness was m a i n t a i n e d .

5.2 TEST PROCEDURE WITHOUT PLATE

T h e r e w e r e four f i r i n g s wi th the pi tot r a k e m o u n t e d in a v e r t i c a l p o s i t i o n and fou r in the h o r i z o n t a l pos i t i on . F o r both of the p o s i t i o n s , the pi tot r a k e was l o c a t e d at 19.75 and 30 .5 in. f r o m the n o z z l e exi t a long the t h r u s t e r c e n t e r l i n e . The e ight t e s t s w e r e c o n d u c t e d at s i m u - l a t e d a l t i t u d e s b e t w e e n 350, 000 and 400, 000 ft. The t e s t c o n d i t i o n s fo r e a c h r u n a r e l i s t e d in T a b l e I, Append ix II.

In p r e p a r a t i o n for f i r i ng , the c h a m b e r was p u m p e d down wi th the m e c h a n i c a l and d i f fus ion p u m p s , and al l c r y o s u r f a c e s excep t the L H e - c o o l e d s u r f a c e s w e r e c o o l e d to o p e r a t i n g t e m p e r a t u r e s . I m m e d i a t e l y b e f o r e f i r i ng , the LHe c r y o p u m p was c o o l e d to 4 .2°K. When th i s s u r - f a ce was cold , the c h a m b e r p r e s s u r e was 1 x 10 -7 t o r t . The eng ine was then f i r e d for p e r i o d s r a n g i n g f r o m 46 to 304 s e c . B e t w e e n f i r i n g s the pi tot r a k e was m o v e d to a n o t h e r ax ia l pos i t i on . A c h e c k f i r i n g was c o n d u c t e d at e a c h p o s i t i o n in o r d e r to c h e c k the r e p e a t a b i l i t y of da ta .

The c h a m b e r was b rough t to a t m o s p h e r i c p r e s s u r e in o r d e r to p o s i t i o n the r a k e in an o r i e n t a t i o n 90 deg r e l a t i v e to the p r e v i o u s r a k e l o c a t i o n , and the t e s t s e q u e n c e was r e p e a t e d wi th the r a k e r o t a t e d .

5.3 TEST PROCEDURE WITH PLATE

T h e r e was a t o t a l of 16 f i r i n g s wi th the pi to t r a k e and p la t e m o u n t e d in a v e r t i c a l p l ane . The t h r u s t e r ax is was m o u n t e d p a r a l l e l to and four n o z z l e r a d i i ( 1 .14 in. ) f r o m the s u r f a c e of the p l a t e . The pi tot r a k e was p o s i t i o n e d m a n u a l l y at ax ia l d i s t a n c e s of 15 and 23 .25 in. d o w n s t r e a m f r o m the n o z z l e exi t p l ane . At e a c h of t h e s e ax ia l s t a t i o n s , the pi tot r a k e was m o v e d f r o m 0.5 to 5 . 0 in. f r o m the s u r f a c e of the p l a t e in v a r i o u s i n c r e m e n t s b e t w e e n the f i r i n g s . E a c h of the t h r u s t e r f i r i n g d u r a t i o n s was a p p r o x i m a t e l y 11 s e c . F o u r p u l s e f i r i n g s w e r e m a d e d u r i n g th i s t e s t to e v a l u a t e c h a m b e r p e r f o r m a n c e u n d e r p u l s e f i r i n g c o n d i t i o n s . The p u l s e width , p u l s e de l ay , and p u l s e n u m b e r w e r e v a r i e d as s h o w n in T a b l e I.

SECTION VI RESULTS AND DISCUSSION

Figure 8 shows typical engine combustion chamber pressure, oxidizer-to-fuel ratio, and oxidizer flow rate during engine firing. These quantities are practically constant after initial transients.

5

A E D C.T R.69.75

F i g u r e 9 shows the p r e d i c t e d r u n t i m e and a l t i t ude c a p a b i l i t y of the ARC 8V c r y o s y s t e m as func t ions of eng ine t h r u s t l e v e l . The da ta point for the 1-1b eng ine is p lo t t ed . F i g u r e 10 shows m e a s u r e d c h a m b e r p r e s s u r e v e r s u s t i m e for a t y p i c a l 1-1b eng ine f i r i ng . The con t inuous r i s e in c h a m b e r p r e s s u r e is c a u s e d by the t h e r m a l l oad ing of the f ron t GHe c r y o p u m p (20°K).

6.t WITHOUT PLATE

P l o t t e d in F i g s . 11 and 12 is i m p a c t p r o b e p r e s s u r e v e r s u s d i s t a n c e f r o m the n o z z l e c e n t e r l i n e at ax ia l p o s i t i o n s of 19 .75 and 30.5 i n . , r e s p e c t i v e l y .

F i g u r e 13 shows the c a l c u l a t e d (Ref . 5) e q u i l i b r i u m e x p a n s i o n s o l u - t i on for Mach n u m b e r c o n t o u r s v e r s u s ax ia l d i s t a n c e f r o m the eng ine exit p l ane . The e x p e r i m e n t a l M a c h n u m b e r s o b t a i n e d f r o m the r a t i o of i m p a c t p r e s s u r e to c o m b u s t i o n c h a m b e r p r e s s u r e a r e p lo t t ed fo r both v e r t i c a l and h o r i z o n t a l p o s i t i o n s . The a v e r a g e s p e c i f i c hea t r a t i o , %' (1 .25 ) , u s e d for c a l c u l a t i n g e x p e r i m e n t a l l o c a l M a c h n u m b e r s f r o m the i m p a c t p r o b e p r e s s u r e s , was ob t a ined f r o m the c o m p u t e r so lu t ion . The e x p e r i m e n t a l M a c h n u m b e r s n e a r and on the c e n t e r l i n e of the t h r u s t e r a g r e e v e r y we l l . The d e v i a t i o n of the M a c h n u m b e r s away f r o m the c e n t e r l i n e is l a r g e r , h o w e v e r , b e c a u s e of the d i f f i cu l t y of m a k i n g a c c u r a t e pi tot r e a d i n g s in th i s p r e s s u r e r a n g e , and th i s is wi th in the e x p e c t e d a c c u r a c y of the m e a s u r e m e n t s .

6.2 WITH PLATE

P l o t t e d in F i g s . 14 and 15 is the t o t a l p r e s s u r e above the s u r f a c e of the p l a t e at ax ia l p o s i t i o n s a long the s u r f a c e of x = 15.0 in. and x = 23 .0 i n . , r e s p e c t i v e l y . E a c h i m p a c t p r o b e p r e s s u r e of the r a k e is p lo t t ed v e r s u s d i s t a n c e above the s u r f a c e of the p la t e . In both F i g s . 14 and 15 the pi tot p r e s s u r e i n c r e a s e s wi th i n c r e a s i n g d i s t a n c e f r o m the p la t e . At x = 15 in. (F ig . 14) the p r e s s u r e r e a c h e s a m a x i m u m at a p r o b e he igh t of about z = 3 in. and t hen d r o p s off, a p p r o a c h i n g the r e a d - ing ob t a ined wi th no p la t e in the flow. At x = 23 .25 in. no m a x i m u m pi tot p r e s s u r e was r e a c h e d wi th the p r o b e 5 in. f r o m the s u r f a c e . S ince the a r e a of p a r t i c u l a r i n t e r e s t was n e a r the s u r f a c e of the p la te , r e a d - ings w e r e not r e c o r d e d when the p r o b e was f a r t h e r t han 5 in. f r o m the p l a t e . It is p o s s i b l e h o w e v e r , p a r t i c u l a r l y f r o m Fig . 15, to s e e tha t the b o u n d a r y l a y e r of the flow a long the p la te i s qui te th ick ; i ts e s t i - m a t e d o u t e r l i m i t is i n d i c a t e d on the f i g u r e s .

A ED C . T R - 6 9 - 7 5

The flow field, wh ich is i n f l uenced by the p la te , is a r a t h e r c o m - p l i c a t e d m i x t u r e of shock p a t t e r n s , bounda ry l a y e r , and con t inued e x p a n s i o n of the gas . Some i n v e s t i g a t i o n s r e p o r t e d in Refs . 4 and 6 which a r e c o n s i s t e n t with the c u r r e n t i n v e s t i g a t i o n s i n d i c a t e that t h e r e is an i m p i n g e m e n t p a t t e r n on the p la te as i l l u s t r a t e d in Fig . 16. The top v iew shows the i n t e r a c t i o n r e g i o n on the pla te , and the bo t t om v iew shows the zone of i n f l uence which the p la te p r o d u c e s on the u n d i s t u r b e d p l u m e along the n o z z l e c e n t e r l i n e .

SECTION VII

CONCLUSIONS

The to ta l p r e s s u r e s u r v e y by the pi tot r a k e in the p l u m e wi thout the p la te i n d i c a t e d that the p l u m e was r e a s o n a b l y a x i s y m m e t r i c , and the Mach n u m b e r s ob ta ined f r o m t h e s e p r e s s u r e s a g r e e d with the a n a l y t i c a l va lues which had been p r e d i c t e d by the e q u i l i b r i u m m e t h o d of c h a r a c t e r i s t i c s c a l c u l a t i o n s .

The p l u m e i m p i n g e m e n t on the p la te r e s u l t e d in a shock and b o u n d a r y - l a y e r r eg ion . The b o u n d a r y - l a y e r r e g i o n was about 4 in. t h i ck 23.25 in. f r o m the n o z z l e exit .

REFERENCES

i . B a u e r , R. C. and Sch lumpf , R. L. " E x p e r i m e n t a l I n v e s t i g a t i o n of F r e e J e t I m p i n g e m e n t on a F la t P l a t e . " A E D C - T N - 6 0 - 2 2 3 (AD253229}, M a r c h 1961.

2. L l i na s , J . , S h e e r a n , J . , and H e n d e r s h o t , K. C. "A Shor t D u r a - t ion E x p e r i m e n t a l T e c h n i q u e for I n v e s t i g a t i n g Solid P r o p e l l a n t Rocke t P l u m e I m p i n g e m e n t E f f ec t s At High A l t i t u d e s . " C o r n e l l A e r o n a u t i c a l L a b o r a t o r y , Buffalo, New York , p a p e r p r e s e n t e d at the I C R P G / A I A A T h i r d Solid P r o p u l s i o n C o n f e r - ence , AIAA P a p e r No. 68-517, J u n e 4-6, 1968.

3. L l i n a s , J . " E l e c t r o n B e a m M e a s u r e m e n t s of T e m p e r a t u r e and Dens i ty in the B a s e Reg ion of a C l u s t e r e d Rocke t Model . " C o r n e l l A e r o n a u t i c a l L a b o r a t o r y , Buffalo, New York , p a p e r p r e s e n t e d at the AIAA Second F l igh t T e s t S imu la t i on and Sup- por t C o n f e r e n c e , No. 68-236, M a r c h 25-27, 1968.

A EDC.T R.69.75

4. Barebo, R. L. and Ansley0 R. C. "Effec ts of Rocket Exhaus t Je t Impingement on a Moveable Fla t P l a t e at P r e s s u r e Alt i tudes above 200, 000 F t . " AEDC-TDR-63-214 , J a n u a r y 1964.

5. Ze lezn ik , F r a n k J. and Gordon, Sanford. "A G e n e r a l IBM 704 or 7090 Compute r P r o g r a m for Computat ion of Chemica l Equi l ib- r i u m Compos i t ions , Rocket P e r f o r m a n c e and Chapman-Jougue t De tona t ions . " NASA TN O-1454, October 1962.

6. Becke t , Manfred and Boylan, David E. "F low Fie ld and Sur face P r e s s u r e M e a s u r e m e n t s in the Fu l ly Merged and T r a n s i t i o n Flow Reg imes on a Cooled Sharp F la t P la t e . " A E D C - T R - 66-111(AD638804) , Sep t ember 1966.

A E D C.T R.69.75

APPENDIXES

I. ILLUSTRATIONS II. TABLE

9

Test P l a t e

Dewar

LN 2 Liner ~ L N 2 Precoo ler

I I ' - . . . . . - I .

I

I I

I - . . . . . ...I

l - l b Engine GHe C r y ° f l n s ( 5 2 ) - - - ~ ~ I

LHe Cryopump - - Rear GHe L i n e r - -

LN 2 D o o r

Fig. 1 Aerospace Research Chamber (8V) r n

N i

-.f ~ J

&

Wate r

t e r ( T y p i c a l )

S o l e n o i d V a l v e ( T y p i c a l )

569

0 . 7 3 0

C o m b u s t i o n Chamber

Fig. 2 One-Pound-Thrust Engine and Valves

.090

D e t a i l A

I n j e c t o r s

r n

i

&

vgn~o

• Band I /4 -Sn , Nail h | v o

Needle h | v e

b l o n o l d b i g *

h l t e t Vulve

114-tn. Cheek VBlvo

rs ) t e r

n ~ t u r

------ h r l t t a l k 4flO Pgl

PTUgImFU TTRUadlJ~OF

n u l b l o C o v p I I q

l = I b R n l t u o

N B P~rse

l l l b Potnt | | o e d

Vstur ~ n t f o l d m

gut4w

. . . . . Q P T

BtSb P o i n t B l o o d 5

N| P r u u u r o

i

~ n p

J %

i A v

Fig. 3 Propellant System

N I I te~a lu ted I ~ N I " - - j

to 80-p l t ~ 8 0

N 2 I t a l ~ l s t e 4 $0 PUt

l l-- I h i l t O Drum g ~ a

I ,..,_.k J 3> m C3

n - 4 ~3 & ~ J ~Jq

T HRUSTE R

PI'I-OT RAKE

I

- F J 2

3.94 ~ /

, . ° , / ~ . . J '

rn

C~

h & ,,0

f j I

Fig. 4 Pitot Probe Rake without Plate

AEDC-TR-69-75

PLATE

THRUSTER

z~

PITOT

I

RAKE

l -

4..44

2 8B

4.50

4.BG

'© 4

82"

go° Q 5

"/5"

~ g

8.25

1__ -,,,<

Fig. 5 Pitat Probe Rake with Plate

15

F--L

n3

N

~J

(.n

Fig. 6 Test Installation - Thruster, Plate, and Pitot Rake

Ana l o g I n p u t S i g n a l s

Test Article Pressures

Temperatures m==O

Flow Rates

S i g n a l Co n d i t i o n 1 n g

Eq u i pme n t

I

Direct Recording Equipment

Oscillograph Strip Charts

I I I - C o m m u t a t o r

Ana l , ) g - t o - =,,I D z g l t : ] 1

C ( ) n v e r t e r

D ] g z t a l i i i T a p e

I _ " I I

Da ta P r i n t o u t ~ C o m p u t e r

1

I I I I i I I I I i I i

1

Fig. 7 Test Data System

l> m

f3

; 0

& ~o i

tJ1

mo

~o

m

B.

=1

Q =0

c g =,1

Ch

amb

er

Pre

ssu

re,

Pc'

psi

a

0 0

0 0

0 0

0

I I

I I

I I

I

m

¢a

CD

O

O

Oxid

izer

Fl

ow Ra

te,

mo,

gm/s

ec,

and

Oxldizer-to-Fuel

Flow

Ra

te Ra

tio,

~O/&F

0 I ~

0

• I

0 ( 4 C C

)

C

o (

0

0

ol>

O

oo

o

0 I ~

, I~

.

m

N

0

I-'

0

• 0

N

~

~ 0

N

0

0 f~

&

-4

0

A E D C - T R - 6 9 . 7 5

10_ 3 3 0 0 , 0 0 0 f t

10 -4 ~ ~ ~ -- 4 0 0 ~ *

/~/r~'-Pressure 10 - 5

- - 5 0 0 , 0 0 0 ft

10 -6 0 . 1

I I I

1 . 0

! I I I

10

I I 1

Engine Thrust, lb

100

10

1

0 . 1 100

q-t E-.

°r-I

, H

Fig. 9

Fig. 9 Predicted ARC 8V Chamber Performance

19

o

0

u'J I 0 e-I

rJ

6

m

o

I1

9 . 0

8 . 0

7 . 0

6 . 0

5 . 0

4 . 0

3 . 0

2 . 0

1 . 0

I I I I I 30 60 90 120 150

T~me, t, s e c

I 180 210

)>

m O N e - I ;0 & ,,o

f j I

Fig. 10 ARC 8V Chamber Pressure versus Engine Firing Time

250

200

b~ -e

4.1

d ~ 50

o IOO °rd

50

0 1 . -20

O

-15

O

O

A

O

gine ¢

-lO -5 0 5

Distance from Engine Axis, y, in.

Fig. 11 Total Pressure Prof i le in Plume at x = 19.75 in.

0

A

A

0

V e r t i c a l

l l o r i z o n t a l

A

0

10 15 20

~> m

| - t ~0

& | - 4 (Jm

2 5 0 >

t ~ b ~

2 0 0

~0

:i

lSO ~J

g N

I1

I 0 0

o

50

0 Vertical

Horizontal

0 -20

D

o o o

A A A

o

- 0

0 q D - - - - - - E n g i n e

A O 1 I I I i ,I

-15 -10 -5 0 5 I0 15 20

D i s t a n c e f r o m E n g i n e A x ~ s , y , ~ n .

I"11

i

i ( ~ , o

. , j ~n

Fig. 12 Total Pressure Prof i le in Plume at x = 30.5 in.

L~3 C~

20

10

y, i n . 0

10

20

0

V - V e r t i c a l R a k e H = H o r i z o n t a l R a k e 7 = 1 . 2 5

- - C h a r a c t e r i s t i c s S o l u t l o n

13

M -=- 7

11

10

Rak e P o s i t i o n

1 0

M

1 5 . 2 V 1 4 . 4 !I

2 0 1 4 . 2 V 1 2 . 0 H

3 0 1 1 . 5 V 1 0 . 7 H

5 % 1 0 . 2 V

6/• 1 0 . I H

1 0 . 4 V 1 0 . 7 H

1 1 . 1 V 7 O I I . 9 H

1 3 . 3 V 8 O 1 4 . 2 H

Rake P o s i t i o n M

1 4 . 4 V I / % 1 2 . 9 H

2 ~ 1 2 . 2 V 1 1 . 7 H

3 A 1 1 . 3 V 1 1 : 5 H

5 t I I . 0 V

/A I I . 0 H

1 1 . 4 V 1 1 . 6 H

7 A l 1 . 4 V 11 7 H

8 A 1 2 . 0 V 1 3 . 4 H

O14.7 V 13.8 H

9 ~ 1 2 . 9 V 1 4 . 4 H

I I 10 20

X , I n .

30

Fig. 13 Mach Humber Contours for 1-1b-Thrust Engine

40

)x m

R3 & ~o

~n

t~

d

3

Probe Location, y, in.

c~ 2 . 4 8

~ A 3.88 n "0

~ 0 2.88 7.38

r

J / V - -

1 ~ ~/~ / ~ /~ " .- Boundary Layer

~ S u r f a c e i 0 l i ),~ /l ~ , / r J / ) , ~ / , -

0 100 200 300 400 500 600 700 800 900 1 ,

Pitot Pressure, , ~ Hg Pt 2

~ f f a

1000 I

r11

N

&

u~

Fig. 14 Total Pressure Survey above Panel Surfaces at x -- 15.0 in.

t ~ Lu

5

O f 0 !

3

°rl

2

No P l a t e , y ~ 0 . 0 l n .

100 200 300 400

Engine

Itrl,,l,,,iF1, i111111rrr~

500 600

Boundary L a y e r

P r o b e L o c a t i o n , y , i n ,

o 12.48 0 8.32

3 . 8 8 G 0.0 0 2.88 O 7.38 0 12.26

x = 23.25 in.

, ~ S u r f a c e

| i i i / I t , r l l l l l l l l t l ~ I I I I I I l l 700 800 900

Pitot Pressure, Pt2 , ~ Hg

Fig. 15 Total Pressure Survey above Panel Surfaces at x = 23.25

1000 m

f~

~0 & ~O

A EDC.T R.69.75

Interaction Region

_ • Outer Shock

Stagnation Region/

/ ~ B o u n d a r y Layer ~::--~ Influence I ~ ] I Pitot Probe

Fig. 16 Impingement Pattern an Plate

28

T A B L E I

TEST LOG

Run No.

1 2 3 4 5 6 7 8 9

i0 11 12 13 14 15 16 17 18 19

20 21 22 23 24

Run T i m e , s e e

61 60 59 60 46 60

304 60 10 11

12 11 11 13 11

151

P u l s e W i d t h / D e l a y / N o .

501 5OllO 50/ 500 /10 50/ 500110 50/1000/10 50/2000/10

P F , PO, z n o , ~hF, P c ,

p s i a p s i a g m / s e c g m / s e c p s i a

125 153 125 125 126 124 154 124 153 123.5 153

153 149

123 123 123 123.5 123.5 123

1 .16 0 .68 0 . 8 0 0, 68 0 .50 0 .71 0 .60 0 .69 1 .00 0 .76 1.14 0 .75 1 .12 0 .76 1.13 0 .76 1 .24 0 .69 1.29 0 .69 1 .30 0 .68 1.25 0 .69 1 .24 0 .69 1 .29 0.7O 1.29 I . 28 1 .29 1 .25 1 .27 0 . 6 9

87 88 89 89 96 96 97 96 86

85 85 87

O/F

1.71 1 .18 0o 705 0 . 8 7 1 .31 1 .52 1 .47 1 .49 1 .80 1 .87 1 .88 1 .81 1 .80 1 .84 1 .84 1.83 1.84 1.79 1.84

X,

in.

19.75 30 .5 19.75 30 .5 19.75 30 .5 19.75 30 .5 15 .0

1 23.25

Z , i n .

1 .14 ( T h r u s t e r C e n t e r l i n e

1 .0 1.5 2 . 0 3 . 0 4 . 0 5 . 0 0 .5 1 .0 1 .5 2 . 0 3 . 0

4 . 0 5 . 0

P i t o t P r o b e Rake P o s i t i o n , in .

V e r t i c a l

H o r i z o n t a l

V e r t i c a l Rake

wi th F l a t P l a t e

I

m Ey

i

&

UNCLASSIFIED ~cudt~ Classification

DOCUMENT CONTROL DATA- R & D fSe©url~ ¢ lass l l lcat lon o f t i t le, b o ~ of abstract and indexin~ ~ n o t a t l o n must be entered when the o ~ t a l l report is c l e s e l n e ~

I O R I G I N A T I N G A C T I V I T Y (Co ,o ra te a u ~ o ~ | ~ . R E P O R T S E C U R I T Y C L A S S I F I C A T I O N

A r n o l d E n g i n e e r i n g D e v e l o p m e n t C e n t e r I UNCLASSIFIED ARO, I n c . , O p e r a t i n g C o n t r a c t o r I'b'GROUP A r n o l d A i r F o r c e S t a t i o n , T e n n e s s e e 37389 N/A

3. R E P O R T T I T L E

INVESTIGATION AT HIGH ALTITUDES OF ROCKET EXHAUST PLUME SYMMETRY AND INTERACTION WITH A PLATE WITH A SCALED MOL THRUSTER

4. D E S C R I P T I V E N O T E S ( T y p e of reporl and Inc lus ive dates) F i n a l Repor t May th rough December 21, 1968

S. A U T H O R(S) (F i rs t name, middle in i t ia l , lae l name)

D. W. H i l l , J r . , AR0, Inc .

6. R E P O R T D A T E 7a. T O T A L NO. O F P A G E S 17b. N O O F R E F S

A p r i l 1969 33 I 6 8a. C O N T R A C T O R G R A N T NO.

F 4 0 6 0 0 - 6 9 - C - 0 0 0 1 b.

P r o g r a m E l e m e n t 3 5 1 2 1 F / 6 3 2 A Co

9a. O R I G I N A T O R ' S R E P O R T N U M B E R ( S )

AEDC-TR-69-75

Sb. OTHER REPORT NO(S) (Any other numbers Chat may be assi j lned t h i s report)

N/A 10'DISTRIBUTIONSTATEMENTThis document may be further distributed by any holder only with specific prior approval of M0L Project Office (SAFSL-SB), AF U ~ P o s t O f f i c e , Los A n g e l e s , C a l i f o r n i a 9 0 0 4 5 .

1 I . S U P P L E M E N T A R Y N O T E S

A v a i l a b l e i n DDC.

12. S P O N S O R I N G M I L I T A R Y A C T I V I T Y

MOL P r o j e c t O f f i c e (SAFSL-5B) AF U n i t P o s t O f f i c e Los A n g e l e s , C a l i f o r n i a 90045

13 A B S T R A C T

A 1 - 1 b - t h r u s t r o c k e t e n g i n e was t e s t e d t o d e t e r m i n e p l u m e s y m m e t r y a n d Mach number c o n t o u r s a t 4 0 0 , 0 0 0 - f t a l t i t u d e . T o t a l p r e s s u r e s u r v e y s w e r e made w i t h a n d w i t h o u t a f l a t p l a t e i n t h e p l u m e . The t e s t s w i t h o u t t h e p l a t e i n d i c a t e d t h e p lume was s y m m e t r i c a l , a n d m e a s u r e d r e s u l t s c o m p a r e d w e l l w i t h c o m p u t e d v a l u e s . In t e s t s w i t h t h e p l a t e , t h e s h o c k i n t e r a c t i o n a n d b o u n d a r y - l a y e r b u i l d u p on t h e p l a t ~ w e r e m e a s u r e d .

T h i s d o c u m e n t may be f u r t h e r d i s t r i b u t e d by a n y h o l d e r o n l y w i t h s p e c i f i c p r i o r a p p r o v a l o f MOL P r o j e c t O f f i c e (SAFSL-5BT~--~F U n i t P o s t O f f i c e , Los A n g e l e s , C a l i f o r n i a 9 0 0 4 5 .

DD '°:v's,14 73 UNCLASSIFIED Security Classification

UNCLASSIFIED Security Classification

| 4 , I . I N K A I . I N K B / I N K C K E Y W O R D S i - i i

R O L E W T R O L E W T R O L I : ; W T

r o c k e t e n g i n e s

a t t i t u d e c o n t r o l

o r b i t a l v e h i c l e s , m a n n e d

p l u m e s

r o c k e t e x h a u s t s

a l t i t u d e s i m u l a t i o n

A F ~

UNCLASSIFIED Security Classification