Armstrong, W. O.

Penland, J. A.

English

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NACA RM L58El3a 
NATIONAL ADVISORY COMMITTEE  FOR  AERONAUTICS 
RESEARCH MEMORANDUM 
PRELIMINARY AERODYNAMIC DATA PERTINENT TO MANNED 
SATELLITE REEJYTRY CONXIG~RATI~NS* ' . ' -  
. . I  . ,  
By J i m  A .  Penland and William 0.  Armstrong 
I , ,  
SUMMARY 
Some recent experimental data, together with calculations made by 
the modified Newtonian and shock-expansion theories ,  are  presented for  
a var ie ty  of aerodynamic shapes considered f o r  use as manned reentry 
vehicles.  These vehicles were grouped i n  three basic  categories: non- 
l i f t ing bodies ,  l i f t ing bodies ,  and airplane-like vehicles.  The r e s u l t s  
indicate  that  from aerodynamic considerations, a l l  of these configuration 
types are suitable for consideration as manned reentry vehicles.  
INTRODUCTION 
The aerodynamic charac te r i s t ics  of s a t e l l i t e  r een t ry  veh ic l e s  at 
hypersonic speeds are essential for adequate prediction of t he i r  r een t ry  
charac te r i s t ics .  The purpose of the present paper i s  to  p re sen t  some 
basic  data  of this type obtained in the Langley 11-inch hypersonic tun- 
n e l  a t  M = 6.9 i n  air .  The data  concern  three  types of configurations: 
(1) Axisymmetrical nonlifting bodies that would follow purely 
ba l l i s t i c   r een t ry   pa ths .  
( 2 )  Bodies equipped with f l aps  capable of being trimmed t o  produce 
f i n i t e  l i f t .  These a re  r e fe r r ed  to  as l i f t ing  bodies .  
( 3 )  Highly swept airplane-like configurations. 
Comparisons of the experimental results with theoret ical  predict ions are 
included. 
. . . "  ~ 
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Title,   Unclassified.  
Restriction/Classification 
Cancelled
Restriction/Classification 
Cancelled
2 
SYMBOLS 
NACA RM L58E13a 
A f r o n t a l  area 
E mean aerodynamic  chord 
CD drag  coefficient,  based on wing area or maximum body cross 
sec t ion  
drag coef f ic ien t  a t  zero angle of a t tack  
CL l i f t  coefficient, based on w i n g  area or  maximum body cross 
sec t ion  
(cL)TFm 
l i f t  coeff  ic ient  a t  C, = 0 
c, pitching-moment coefficient,  based on mean aerodynamic 
cP 
%,MAX 
chord or body length 
pressure coeff ic ient  
max imum pressure coefficient 
d  diameter 
if e levator  incidence  a gle 
i N  nose incidence angle 
2 body length 
L/D l i f  t-drag rat i o  
( L / D ) ~ *  l i f t - d r a g  r a t i o  a t  C, = o 
M Mach number 
R Reynolds number based on mean aerodynamic chord or maximum 
body diameter 
r radius  
Sf unshielded area of f l aps  
NACA RM L58El3a 
SRFF reference  area 
W weight 
X 
CP 
center of pressure, percent body length 
a angle of a t tack 
6 f low-def lection  angle 
0 cone semiapex  angle 
CONFIGURATIONS 
Sketches of the test  configurations .are shown in  f igu re  1. The . 
configurations include seven nonlifting bodies, two l if t ing bodies, and 
two airplane-like configurations. 
RESULTS AND DISCUSSION 
Nonlifting Bodies 
For nonlifting reentry vehicles, the aerodynamic charac te r i s t ic  of 
main i n t e r e s t  i s  the drag coefficient,  since W/C$ i s  the predominant 
variable in determining range and heating. Figure 2 compares the mas- 
ured drag a t  M = 6.9 of a se r i e s  of cones  and cone-cylinders of various 
apex angles a t  zero angle of a t tack with predictions made by shock- 
expansion theory and by modified Newtonian theory; that is, the loca l  
pressure  coefficient i s  given by Cp = C p , w  sin26 where 6 is the 
flow-deflection angle (refs. 1 and 2).  Calculations by shock-expansion 
and modified Newtonian theory were made for  only the cones, with no 
allowance for skin friction. Additional experimental  data are given in 
reference 3 f o r  cones and cone-cylinders i n  which the afterbodies were 
4 diameters long. 
Figure 2 shows good agreement between the predictions by shock- 
expansion theory and experimental data up. t o  a semiapex angle nem shock 
detachment (55.7' f o r  M = 6.9) . Modified Newtonian theory shows rather 
poorer agreement with experiment and tends t o  underpredict drag f o r  the 
l ess  b lunt  cone shapes and to overpredict  d r a g  for the  more blunt shapes. 
It may a l so  be seen from this f igure that the increase in experimental  
with increasing apex angle beyond shock detachment is r e l a t i v e l y  
small. Th i s  va r i a t ion  in  ( C I j ) ,  follows a l inear  pa th  beyond shock 
detachment, w i t h  the va lue  for  a c i rcu lar  d i sk  normal to  the  s t ream 
(0  = 90')  f a l l i n g  between the values calculated by assuming stagnation 
pressure and s t a t i c   p re s su re  behind the normal shock. 
The drag coef f ic ien ts  and center-of-pressure location f o r  a repre- 
sentative group of nonlifting reentry shapes over a wide Mach number 
range are shown i n  f i g u r e  3 .  A l l  data  shown i n  this figure other than 
t h a t  a t  M = 6.9 were obtained from references 4 t o  8. The drag coef - 
f i c i e n t  (lower half of f igure  ) predicted by modified Newtonian theory 
remains relat ively  constant   with Mach number above a Mach number of 
about 4. T h i s  predict ion is  fairly wel l  ver i f ied  by experimental data 
taken on the cylinder and sphere, wbich were t e s t ed  up t o  Mach numbers 
of about 7 and 10, respectively.  The measured data indicate that there  
i s  l i t t l e  change i n  drag w i t h  Mach number i n  the hypersonic speed range 
from 7 t o  10 and it appears reasonable t o  assume that i n  continuum flow 
these data  axe representat ive of the entire hypersonic speed range. 
The upper half of figure 3 shows that modified Newtonian theory 
fairly accurately predicts the center-of-pressure location f o r  those 
bodies shown. It appears that these bodies can be made s t a t i c a l l y  s t a b l e  
in the hypersonic speed range with practical center-of-gravity locations. 
Lif t ing Bodies 
The second group considered i n  this paper consists of high-drag 
configurations which can uti l ize some lift t o  decrease reentry decelera- 
t i ons  and provide limited range control. 
The accuracy w i t h  which predictions m a y  be made on simple bodies 
over a wide angle-of-attack range is of fundamental i n t e r e s t  when con- 
s iderat ion i s  given the aerodynamics of high-drag l i f t ing configurat ions.  
Figure 4 compaxes the experimental drag coeff ic ient  of a se r i e s  of cones 
of various apex angles a t  M = 6.9 and at angles of a t tack  up t o  1300 
with calculations made by the modified Newtonian theory. It is  seen 
that the modified Newtonian theory gives an excellent  representation of 
the trends of the drag  coeff ic ient   f6r  cones with angles of attack from 0' , . '  ' 
t o  130~ .  , .  
Figure 5 shows the d e t a i l s  of configuration 2-A, a drag-type reentry -;,::- 
vehicle w i t h  f l a p s   f o r  trirnming the vehicle at some positive angle of 
a t tack ,  to  obta in  l i f t  f o r  trajectory-path control.  This configuration 
consists of a frustum of a l 5 O  half-angle cone with a spherica1,nose. 
The untrimmed experimental and modified Newtonian lonaitudinal char- ' 
a c t e r i s t i c s  of this configuration axe shown -i n  f igu re  6. The configuration 
1 
NACA RM L58E13a c 5 
i s  s ta t ical ly  s table  about  a moment reference center a t  50 percent of 
the body length. Theory and experiment are in  exce l l en t  agreement f o r  
pitching moment.  The l if t-curve slope i s  posi t ive and the  l i f t  coef- 
f i c i en t  i s  also  predicted fairly wel l  by theory  through the angle-of- 
attack  range. The predictions of CD and L/D a re  much less  accurate 
than  are  the  predictions of CL and Cm, as is t o  be expected,  since 
theory underpredicts drag for this configuration. 
The experimental  tr im characterist ics of this configuration a t  
M = 6.9 are shown i n  figure 7. The f l aps  used f o r  trim have an effec- 
t i v e  area equa l  t o  8.84 percent of the body base area. The configura- 
t i o n  i s  s t a t i c a l l y  s t a b l e  f o r  a l l  conditions of t h e  t e s t s .  With f l a p  
deflections of -20' and -40°, the vehicle w a s  trimmed at  angles of 
a t tack of bo and loo, respectively.  There i s  a noticeable reduction in 
L/D due to  increas ing  t r im drag with increasing trim effectiveness. 
Figure 8 i s  a detai led sketch of configuration 2-B, which repre- 
sents  a more blunt reentry vehicle.  This model consists of a reverse 
frustum of a 15' half-angle cone with spherical bases. The vehicle i s  
trimmed with a drag-type flap, located on the circunferent ia l  edge of 
the front  surf ace, which has an area 4.5 percent of the base reference 
area. Figure 9 presents the untrimmed ( f l a p  removed) longitudinal sta- 
b i l i t y  c h a r a c t e r i s t i c s  of this reentry vehicle through an angle-of-attack 
range from 0' t o  90'. This figure gives an indication of the general 
aerodynamic charac te r i s t ics  of a very blunt  reentry body over a wide 
angle-of-attack range and compares the results of experimental data with 
that  obtained by modified Newtonian theory. 
The trends of CL,  CD, and L/D are predicted  reasonably  well by 
the modified Newtonian theory; however, pitching-moment coeff ic ient  i s  
not very accurately predicted. It can be seen from the pitching-moment 
data t h a t  this body is  s t a t i ca l ly  s t ab le  up t o  an angle of a t tack of 45'. 
The l i f t -curve slope fo r  t h i s  veh ic l e  i s  negative and maximum L/D i s  
about 0.5 at  an angle of a t tack of -40'. Configuration 2-B has approxi- 
mately the same volume as configuration 2-A (shown i n   f i g .  5 ) ,  but as 
a result of the increase in  body bluntness, configuration 2-B has approx- 
imately three times the drag of configuration 2-A. 
The experimental trim charac te r i s t ics  of model 2-B with the f laps  
on are shown i n  f i g u r e  10. The pitching moment and l i f t -d rag  r a t io  are 
presented  for  various  flap  angles  through  an  angle-of  -attack  range 
from 0' t o  45'. This vehicle i s  statically stable throughout the range 
of angles of at tack of the tests and was trimmed a t  angles of a t tack up 
t o  23' with f lap def lect ions up t o  140O. The  moment reference for  these 
tests w a s  29 percent of the body length from the nose. The l i f t -drag  
r a t i o  f o r  t h i s  v e h i c l e  i s  negative for positive angles of attack, and 
shows l i t t l e  change  due t b  trim. Because of the negative lift-curve 
slope, this configuration would have t o  be flown at negative angles of 
a t tack to  generate  posi t ive l i f t .  
Airplane-Like Configurations 
. The f ina l  ca tegory  of manned reentry vehicles considered in this 
investigation i s  the airplane-like configuration, o r  gl ider ,  u t i l i z i n g  
both hi& l i f t  and high drag to  cont ro l  reent ry  dece lera t ions .  T h i s  
vehicle can be operated at a higher L/D than the other two basic 
reentry  categories  discussed.  his higher L/D permits  the  glider t o  
exercise grea-her control over range and posit ion,  and therefore more 
l a t i t ude  i s  allowed in  landing-s i te  se lec t ion  and touchdown. Figure 11 
shows the all-wing configuration 3-A. This delta-plan-form configura- 
t i o n  is trimmed longi tudinal ly  by a combination of nose and f lag def lec-  
t ions .  As  ind ica ted  in  th i s  f igure  the  nose can be deflected upward t o  
an angle of 20’ and the f l aps  can be deflected from 20’ t o  -20°. Direc- 
t ional   control   can be, maintained by l a t e ra l   de f l ec t ion  of leading-edge 
s ide plates  located at  the rear  of the model. 
Figure 12 presents the untrimmed longitudinal-stabil i ty character-  
i s t i c s  of th i s  vehic le  a t  a Mach  number  of 6.9. The experimental values 
of (&; CL, CD, and L/D a re  compared with values obtained by  shock- 
expansion theory over the angle-of-attack range. The two-dimensional 
theory used here would be expected t o  overestimate the l i f t  and drag 
a t  high angles of a t t ack  because of leading-edge-flow-detachment e f f ec t s .  
However, the theory does predict fairly accurately the pitching-moment 
coefficient throughout the range of angles of attack. This configuration 
i s  s ta t ical ly  s table  with the center  of gravi ty  located at  42 percent 
mean aerodynamic chord and has a maximum untrimmed L/D of about 2.. 
The t r im capabi l i t i es  of configuration 3-A are  presented in  f ig-  
ure 13 for various nose and f l ap  de f l ec t ions .  P lo t t ed  in  th i s  f i gu re  
are (CL)mI” (L/D)TRIM , and f lap incidence for  trim against angle of 
a t t ack  fo r  nose se t t i ngs  of Oo, loo, and 20°. The data cover a t r i m  
angle-of-attack range up t o  30°. I f  the experimental data are extrapo- 
lated,  it appears that  with various combinations of nose and f l a p  
sett ings this vehicle can probably be trimmed at  angles of a t tack 
approaching 50’. ~aximm ( L/D)mm. i s  about 1 .7  a t  a . =  loo and 
decreases to  va lues  less  than  1.0 a t  the higher angles of a t tack.  
Figure 14 shows d e t a i l s  of configuration 3-B, which consists of a 
f la t  delta-wing model with a spherical  nose, a large uniform leading- 
edge radius, and a cone-shaped body mounted on the upper surface. 
NACA RM L58E13a - 7 
The  untrimmed  longitudinal  characteristics  of  this  configuration 
at M = 6.9 are  shown  in  figure 15. This  model  appears  to  have  a  region 
of  low  static  stability  at  small  angles of attack  but  shows  increasing 
stability  with  increasing  angle  of  attack.  The  maximum L/D is 
about 2.9  and occws at  an  angle  of  attack  of 10'.
CONCLUDING REMARKS 
The  aerodynamic  characteristics  of  several  possible  types  of  satel- 
lite  reentry  configurations  have  been  investigated  at  a  Mach  number 
of 6.9 in  the  Langley  11-inch  hypersonic  tunnel.  It  has  been  found 
that  for  the  configurations  investigated,  satisfactory  static  longi- 
tudinal  stability  characteristics  can  be  obtained.  Simple  fins or flaps 
appeared  to  be  satisfactory  for  trimming  the  blunt  lifting  bodies.  For 
the  winged  configurations  which  were  required  to  trim  at  angles  of  attack 
near 4 5 O  in  order  to  provide  maximum  lift,  a  combination  of  deflected' 
nose  section  and  flaps  was  found  to  be  effective  in  providing  the 
required  trim  moments. 
Langley  Aeronautical  Laboratory, 
National  Advisory  Committee  for  Aeronautics, 
Langley  Field,  Va. , March 18, 1958. 
8 NACA RM L58E13a 
1. Grhminger, G. , Wiliams, E. P., and Young, G. B. W. : Lift on 
Inclined Bodies of Revolution i n  Bygersonic Flow. Jour. Aero. 
Sci.,  vol.  17, no. 11, Nov. 1950, pp. 675-690. 
2.' Penland, J. A.: Aerodynamic Character is t ics  of a Circular Cylinder 
a t  Mach Number 6.86 and Angles  of' Attack up t o  go0. NACA mJ 3861, 
1957. (Supersedes NACA RM L54Alk. ) 
3: Cooper, Ralph D., and Robinson, Raymond A.: An Investigation of the 
Aerodynamic Character is t ics  of a Series of Cone-Cylinder Configura- 
' t i ons  a t  a Mach  Number of 6.86. NACA-RM L'jlJO9,  1951. 
4. Potter,  J. k i t h ,  Murphree, Wiliam D., and  Shapiro,. Norman,".:  Nor- 
mal Force and Center of Pressure on Right Circular Cylinders. Jour. 
Aero. Sci. (Readers' Forum), vol. 22, no. 3, Mar. 1955, pp. 214-215. 
5. Long, J. E. : Supersonic Drag Coefficients of Circular Cylinders up 
t o  Mach Number 8.  NAVORD Rep. 4382, U. S. Naval Ord. Lab. (White 
Oak, Md.), Oct. 26, 1956. 
6. Charters, A. C., and Thomas R. N.: The Aerodynamic Performance of 
Small Spheres From Subsonic t o  High Supersonic Velocities. Jour. 
Aero. Sci., vol. 12, no. 4, Oct. 1945, pp. 468-476. 
7. Hodges, A. J.: The Drag Coefficient of Very High Velocity Spheres. 
Jour .  Aero. Sci.,  vol. ,24, no. 10, Oct. 1957, pp. 755-758. 
8. Seiff, Alvin, S m r ,  Simon C., and Canning,. Tbhmas N. : Some Exper- 
iments a t  High Supersonic Speeds on the Aerodynamic and Boundary- 
Layer Transi t ion Character is t ics  of High-Drag Bodies of Revolution. 
NACA RM A56105, 1957. 
( 
-I 
M C A  RM L58E13a 
CONFIGURATIONS TESTED 
NONLlFTlNG BODIES 
" 
e I -A  
0 I - B  
0 I -E  
Figure 1 
VARIATION OF CONE DRAG WITH SEMIAPEX ANGLE 
M = 6.9; Q = 0" 
2.0 - 
CD FROM STAGNATION 
PRESSURE BEHIND ,/ L- 
1.2 - 
NORMAL SHOCK 
(CD) 
a=O0 
0 CONE CYLINDER 
CONE 
SHOCK EXPANSION -"" MODIFIED NEWTONIAN 
0 15 30 45 60 75 90 
SEMIAPEX ANGLE, 8, DEG 
- LIFTING BODIES 
2 - 1  
J 7 2 - I  
LIRPLANE-LIKE BODIE! 
PLAN FORM e 
SIDE VIEW 
3 - A  
PLAN FORM 
4 
SIDE VIEW 
3 - B  
Figure 2 
10 NACA FN LfS8E13a 
EFFECT OF MACH NUMBER ON DRAG AND CENTER OF PRESSURE 
OF NONLIFTING REENTRY BODIES 
I I I I I J 
0 4 8 12 16 20 
M 
0""- a 1-8 
0"- d> I-c 
a- 0 I-D 
0" 0 I-E 
Q ""- a I-F 
a"" a I-G 
F i m e  3 
DRAG COEFFICIENTS OF A SERIES OF CONES OVER A WIDE RANGE OFa  
M = 6.9 
MODEL  CONE  EXP. N ~ ~ ~ ~ ~ ~ ~ N  RENOLDS 
NUMBER 
-5" 0 - 0.22 x I06 
.55 x I06 
4 20' n --- .43 x I06 
f i  I(D1SK) 90' A ------- .25 X to6 a 45O 0 --- 
Figure 4 
I NACA RM L58E13a 
DETAILS OF  CONFIGURATION 2 - A  
Sf = 8.84% SREF 
Figure 5 
LONGITUDINAL  CHARACTERISTICS OF CONFIGURATION 2-A 
M = 6.9; R ~0.17 X IO6 
MODIFIED 
C.g.AT .50 1 
.7& -.- a 
11 
01, DEG 
Figure 6 
12 1. NACA RM L58El3a 
,EXPERIMENTAL TRIM CHARACTERISTICS OF CONFIGURATION 2-A 
M =6.9; R = 0 . 1 7 X  IO6 
a, DEG 
Figure 7 
DETAILS OF CONFIGURATION 2-8  
sf = 4.5% SREF 
2.57"r 
.45  
Figure 8 
LONGITIDUAL  STABILITY  CHARACTERISTICS 
OF CONFIGURATION 2-B 
M = 6.9; R = 0.25 X IO6 
F-" A A 
I i - I MODIFIED 
NEWTONIAN 
" 
"- 
1 obLr 
- .6 
0 15 30 45 60 75 90 
a. DEG 
Figure 9 
EXPERIMENTAL  TRIM  CHARACTERISTICS 
OF CONFIGURATION 2-8 
M = 6.9; Sf = 4.5% SREF 
i f ,  DEG 
0 0  
-.6 ' ~ I I I I I 0 IO 20 30 40 50 
a, DEG 
" 
Figure 10 
14 NACA RM L58E13a 
0.1 I' r 
DETAILS OF CONFIGURATION 3 - A  
c.g. AT 0.42T 
Figure 11 
UNTRIMMED  LONGITUDINAL 
STAB1 LlTY CHARACTERISTICS OF CONFIGURATION 3 -A 
M= 6.9; C.g. AT 0.42 E ;  R = 0.45 X I06 
-SHOCK-EXPANSION 
.I - THEORY 
C m  0 L - w .  - A ,-, 
L mrn 
- . I  I I I 4" I 
2 
L 
D 
-
I 
0 IO 20 30 40 50 
a, DEG 
Figure 12 
NACA RM L58E13a - 15 
TRIM CAPABILITY  OF  CONFIGURATION 3-A 
- M = 6.9; R = 0.45 X IO6 
L -
TRIM 
I " -2. 
0 I J 
Figure 13 
DETAILS OF CONFIGURATION 3-8  
C.g. AT 0.37 
2.88" 
A c.25" 
3.75" 
16 NACA RM L58E13a 
LONGITUDINAL CHARACTERISTICS OF CONFIGURATION 3-8 * 
M = 6.9; R = 0.25 X IO6 .02r I - 
0. 
Cm - 
- c.g. AT 0.37 F -.02 
- 
-.04 I I I I I 1 I I 
I 3 2 ' E  L 
-lo 
NACA - Langley Field, VJ. 


Preliminary aerodynamic data pertinent to manned satellite reentry configurations

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