Static stability and control characteristics of dihedral right triangular pyramid lifting reentry vehicle configuration

Foss, W. E., Jr.

Whitcomb, C. F.

English

NASA Technical Reports Server

cis';: 
PBtW 
TEC~NI~AL BRAND 
https://ntrs.nasa.gov/search.jsp?R=19660024027 2020-03-24T02:15:54+00:00Z
t 
* 
L 
9 
2 
9 
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 
TECIWICAL MEMoRANixlM x-295 
STATIC STABILITY AND C O E R O L  CHARACTEXISTICS OF 
TWO LARGE-DIBEDReL RIGET 'IXLARGIJ'LAR PYRAMID 
L I F T I N G  REENTW CON3?IGURATIONS AT A 
a 
MACH NUMBER O F  3.05" 
By Charles F. Whitcomb and Willard E. Foss, Jr. 
SUMMARY 333 17 
An investigation has been conducted in the Langley 9- by 12-inch 
blowdown tunnel at a Mach number of 3.05 on two large-dihedral right 
triangular pyramid models to determine the stability characteristics 
with and without deflection of base-mounted controls. 
The investigation showed that the static longitudinal stability 
characteristics of the two models were generally satisfactory and the 
characteristics for one of the models agreed well with a similar model 
tested at l o w  speeds. 
and the higher aspect ratio had a lower maximum lift-drag ratio. 
controls investigated on these models appear to be capable of trimming 
the models at lift coefficients and angles of attack in a region where 
decreased heat transfer occurs for vehicles of this shape. 
effectiveness of the controls on one of the models decreases to adverse 
effectiveness at an angle of attack slightly above zero lift, and large 
adverse yawing-moment coefficients occur throughout the test angle-of- 
attack range. 
The model with the lesser leading-edge s w e e p  
The 
The roll 
I N T R O ~ C T I O N  
A program is being conducted by the National Aeronautics and Space 
Administration to provide information on various manned, lifting reentry 
configurations. 
static stability and control information at a Mach number of 3.05 on 
The present investigation was made to provide some 
* 
Title, Unclassified. 
2 b 
t 
two right triangular pyramid models conceived from the heat-transfer 
considerations of reference 1. The lower surfaces of the models have 
45' dihedral and the upper surface is flat. 
models was 79.3' and 75.0°. 
tics on somewhat similar models have been presented for the low speed 
range in reference 2 and for a Mach number of 6.2 in reference 3 .  
models of the present investigation incorporated a rounded lower-surface 
ridge line similar to that for the model in reference 3. The model for 
the tests of reference 2 had a sharp ridge'line. 
Leading-edge sweep of these c 
Static longitudinal stability characteris- 
The 
Data presented include longitudinal, lateral, and directional sta- 
bility characteristics for one of the models and longitudinal character- 
istics only for the second model. 
mounted controls tested'with and without deflection. 
of the lower-surface ridge line was varied between -6' and 22' and for 
the more highly swept model the angle of sideslip was varied between -5' 
and 20°. 
The models were adapted with base- 
The angle of attack 
SYMBOLS 
b 
All coefficients presented in this paper are based on the projected 
plan-form area of the models. 
axis system for the longitudinal tests and to the body-axis system for 
the sideslip tests. The origin of the axis system in both cases was 
located to correspond to a longitudinal center-of-gravity position of 
45 percent of the mean aerodynamic chord and to a vertical position on 
a line connecting the centroid of the base to the apex of the model. 
Stability data are referred to the wind- 
b model span, in. 
- 
C model mean aerodynamic chord, in. 
Lift lift coefficient, -
qs 
CL 
lift coefficient at zero pitching moment ( c ~ )  trim
CD 
Drag 
qs 
drag coefficient, 
Pitching moment pitching-moment coefficient, 
qsE Cm 
pitching-moment coefficient at zero lift Cm, 0 
. 
f 
L 
9 
2 
9 
3 
Yawing moment 
qfl, 
yawing-moment coefficient, 
Rolling moment 
qfl, 
rolling-moment coefficient, 
side-force.coefficient, Side force 
9s 
lift-drag ratio 
maximum lift-drag ratio 
Mach number 
dynamic pressure, lb/sq in. 
radius 
projected plan-form area of model (not including flaps), sq  in. 
location of aerodynamic center, fraction of mean aerodynamic 
chord measured from leading edge 
angle of attack of model ridge line, deg (See fig. 1.) 
angle of sideslip (positive when nose deflected left), deg 
ncminal control deflection relative to adjacent surface 
(positive when control deflected inward) , deg 
C k  = % per degree a, 
per degree 
- - per degree 
per degree acy cy = -
as 
4 
. . . 
b 
I 
APPARATUS AND METHODS 
C 
Models 
Two models were investigated. Model 1 had a leading-edge sweep 
of 79.3' and model 2 had a leading-edge sweep of 75.0'. 
table I present the dimensional details. 
structed of brass, were equipped with rectangular-slab-type controls 
located at the trailing edge of each of the three surfaces. Dimensional 
details of the controls are presented in figure 1 and photographs of the 
models with upper-surface controls deflected are presented in figure 2 .  
Figure 1 and 
The models, which were con- 
For both models, transition strips of carborundum grit were placed 
on the lower surfaces. The photographs of figure 2 show the location of 
the strips across the curved ridge line through the points of tangency 
of the curved apex with the model leading edge and along the lines where 
the curved ridge line becomes tangent to the large dihedral surfaces. 
The size of the grit was about 0.002 inch. 
studies indicated that no strip was necessary on the flat upper surface 
because turbulent flow already existed. 
Preliminary visual flow 
Tests 
The investigation was conducted in the Langley 9- by 12-inch blow- 
6 
The mean aerodynamic chord was 6.6 inches for model 1 and 
The angle of attack was varied from -6' to 2' 
Sta- 
down tunnel at a Mach number of 3.05 at a stagnation pressure of 
50 pounds per square inch absolute. The corresponding Reynolds number 
based on mean aerodynamic chord was 4.3 x lo6 for model 1 and 3.5 x 10 
for model 2. 
5.4 inches for model 2. 
and for model 1 the angle of sideslip was varied from -5' to 20'. 
bility information was obtained for both models with all controls set 
at Oo deflection. The stability characteristics with controls deflected 
were determined by using 20' settings of several control configurations. 
Excessive balance loads in the longitudinal tests of model 2 limited the 
negative deflection angle of the upper-surface control to -10'. For this 
model positive deflection of this control was also reduced to 10' for one 
test condition while for another test condition the deflection was 20 . 0 
The models were mounted on a six-component internal strain-gage bal- 
ance which in turn was sting mounted to the model-support system. The 
mechanically set angles of attack were corrected for sting and balance 
deflections under load and for a tunnel downflow angle of 0.3'. The data 
were adjusted to a condition of free-stream static pressure at the base 
of the model. The estimated maximum errors of the quantities presented 
in this paper are as follows: 
c 
5 
L 
9 
2 
9 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .  f0.02 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  kO.005 
.20.002 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .  fo.OO1 
fO.OO1 
.fO.ool . . . . . . . . . . . . . . . . . . . . . . . . . . . .  .to.001 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .  20.10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  fO.10 
. . . . . . . . . . . . . . . . . . . . . . . . . . . .  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  
RESULTS AND DISCUSSION 
Longitudinal Characteristics 
The longitudinal characteristics of the two  models with undeflected 
controls are presented i n  figure 3. 
edge sweep and the higher aspect r a t i o ,  has the higher lift-curve slope. 
The slopes l i s ted  i n  table 11, which presents a s w  of the t e s t  data, 
were determined near zero l i f t .  The slope of 0.020 f o r  model 1 i s  about 
17 percent higher than that for  the somewhat similar model with a trail ing- 
edge extension (referred t o  as a Oo boattail) tested a t  a Mach number of 
6.2 i n  reference 3.  This difference is  attributed t o  the decrease i n  lift- 
curve slope with increasing Mach number. Model 2, having the higher aspect 
ratio,  has a larger frontal area and a resultant higher minimum CD than 
model 1. (See fig.  3.) This increase i n  minimum CD was not overcome by 
the l o w e r  drag due t o  lift of the model with the higher aspect r a t io  and 
consequently model 1 had the higher values of (L/D)- - 3.4 as compared 
t o  2.8 f o r  model 2. (See table 11.) 
order of the values obtained for  the models with trailing-edge extensions 
of the lower and higher speed t e s t s  of references 2 and 3, respectively. 
"he aerodynamic center of model 1 i s  located a t  about O.5Z, which is  
almost exactly the same location as for the model with extensions tested 
i n  reference 2 a t  l o w  speeds. 
reference 3 a t  
0.63E. 
Model 2, which has the lesser leading- 
This value f o r  model 1 i s  of the 
For the model with extensions tested i n  
M = 6.2, the aerodynamic center was farther rearward a t  
The location i s  0 . 6 1 ~  f o r  model 2 of the present tes t s .  
The longitudinal characteristics of model 1 with deflected controls 
are presented i n  figure 4 and f o r  model 2 i n  figure 5. 
the controls were inward (plus) o r  outward (minus) 2 0 O  except for the 
previously mentioned case of two model 2 configurations for which the 
inward and outward deflections of the upper-surface control were 100. 
The results which are summarized i n  table I1 indicite that deflection 
of the pitch controls affected the aerodynamic-center location of the 
Deflections of 
6 
b 
I 
models as well as the Cm,, and (CL)trim. This change of aerodynamic- 
center location was not true of the tests of reference 2. The results c 
presented in figures 4 and 5 include those for each model with all three 
flap controls deflected inward 20'. 
a 20° boattail extension similar to the boattail extensions tested in 
references 2 and 3 .  For each model, the simulated boattail increased 
the 
ter forward toward the assumed center of gravity. 
These tests were made to simulate 
(L/D)- (see figs. 4(c) and 5(c)) and moved the aerodynamic ten- 
Heat-transfer considerations of this type of model presented in 
reference 1 refer to angles of attack where the reentry heat-transfer 
problem is reduced. This angle of attack for model 1 is 10.5' and for 
model 2 is about 1.5'. These angles of attack correspond very closely 
to the angles of attack and lift coefficients for trim of the two models 
with zero flap deflection. Reference 1 also indi- 
cates that higher angles of attack than those indicated previously would 
result in a further alleviation of the heat-transfer problem. 
trols as investigated are capable of trimning each of the models for 
angles of attack up to 2 3 O .  
ble of trimming the models at lift coefficients and angles of attack in 
a region where reference 1 indicates decreased heat transfer. " 
(See figs. 4 and 5.) 
The con- 
* 
The controls, therefore, appear to be capa- 
Figure 6 presents the variation of incremental rolling- and yawing- 
moment coefficients with angle of attack that results from deflection 
for roll of the lower-surface control flaps of model 1. 
control effectiveness d.ecreases to an adverse effectiveness at an angle 
of attack of 12' or an angle a few degrees above zero lift. 
controls produced large adverse yawing-moment coefficients throughout the 
test angle-of -attack range. 
The favorable 
The deflected 
Variable Sideslip Characteristics 
The variation of Cn, Cl, and Cy with p for model 1 at an angle 
Of attack of about 7.70 is presented in figure 7. 
results for the model with undeflected controls and the model with lower- 
surface controls deflected to determine their directional effectiveness. 
The stability derivatives Cn,, Cz, and Cy, are listed in table 11. 
These slopes were obtained near an angle of sideslip of 0'. 
particular test angle of attack, the derivatives for the model with 
undeflected controls agree very well with the low-speed results of ref- 
erence 2. The model with undeflected controls is directionally stable, 
and the directional stability increases with deflection of the lower- 
surface controls. The model has comparatively large effective dihedral 
on which the controls have little effect. 
The figure includes 
For the 
L 
t; 
d 
. 0.0. ,?, 0 0  0.0 0.0. 0 .  0. 0 0  0. . 
0 0  00  0 .  0. ...... 
0 . .  0 .  0 0  0 .  
0 0  0.0 0 .  0 . 0 0.0 0 0  
CONCLUSIONS 
7 
The investigation of two similar lifting reentry configurations at 
a Mach number of 3.05 with and without deflected controls indicates the 
following conclusions: 
1. The static longitudinal stability characteristics of the two 
models were generally satisfactory and the characteristics for one of 
the models agreed w e l l  with a similar model tested at l o w  speeds. 
2. The model with the lesser leading-edge sweep and the higher 
aspect ratio had a lower maximum lift-drag ratio. 
3 .  The controls investigated on these models appear to be capable 
of trimming the models at lift coefficients and angles of attack in a 
region where decreased heat transfer occurs for vehicles of this shape. 
4. The r o l l  effectiveness of the controls on one of the models 
decreases to adverse effectiveness at an angle of attack slightly above 
zero lift, and large adverse yawing-moment coefficients occur throughout 
the test angle-of-attack range. 
Langley Research Center, 
National Aeronautics and Space Administration, 
Langley Field, Va., March 17, 1960. 
REFERENCES 
1. Cooper, Morton, and Stainback, P. Calvin: Influence of Large Positive 
Dihedral on Heat Transfer to Leading Edges of Highly Swept Wings at 
V e r y  High Mach Numbers. NASA MI340 3-7-59L, 1959. 
2. Paulson, John W.: Low-Speed Static Stability and Control Character- 
istics of a Model of a Right Triangular Pyramid Reentry Configuration. 
NASA ME340 4-11-59L, 1959. 
3 .  Mayo, Edward E.: Static Longitudinal Stability Characteristics of a 
Blunted Glider Reentry Configuration Having 79.5O Sweepback and 
43O Dihedral at a Mach Number of 6.2 and Angles of Attack Up to 20°. 
NASA TM X-222, 1959. 
8 
............... ....... . . . . . . . . . . . . . . . .  ............................... 0: .............................. ........ 0i ... : . 0 .  0 .  ....... 0 .  0 . .  . 
1 
TABU I.-'DIMENSIONAL CHARACTERISTICS OF MODEL 
Model 1 Model 2 
A i r f o i l  sect ion . . . . . . . . . . . . . . . . . .  
Area (not including f l a p  area), sq i n .  
Span, i n .  . . . . . . . . . . . . . . . . . . . .  
A s p e c t r a t i o  . . . . . . . . . . . . . . . . . . .  
Tip c h o r d , i n .  . . . . . . . . . . . . . . . . . .  
Mean aerodynamic chord, i n .  . . . . . . . . . . .  
. . . . . .  
Root chord ( length) ,  in .  . . . . . . . . . . . . .  
Sweepback o f  leading edge, deg . . . . . . . . . .  
Dihedral, deg . . . . . . . . . . . . . . . . . .  
Control-surface chord, i n .  . . . . . . . . . . . .  
Ridge-line radius,  i n .  . . . . . . . . . . . . . .  
Wedge 
20.4 
4.02 
0.79 
8.50 
0 
6.60 
79.3 
45 
0.945 
0.63 
Wedge 
4.91 
21.3 
1.13 
7.11 
5.43 
75.0 
45 
1 .oo 
0.75 
0 
c 
2 2  
1 .0022 
9 
!I!ABLJI 11.- SUMMARY OF TEST DATA 
(a) Longitudinal tests 
Configuration 
(EN = 200 except 
where noted) 
- Xac
E 
Model 
1 0.16 
.21 
.14 
19 
0.020 
.025 
.01g 
.023 
3.4 
2.8 
3.6 
3.0 
-0.117 
- .156 
-.On 
-0097 
- .170 
- .112 
- .170 
- .156 
0 567 
.606 
9 527 
547 
.620 
.562 
.620 
.606 
0.008 
.014 
.001 
-003 
.047 
- .025 
.046 
- .030 
0.07 
-09 
.01 
03 
.28 
-.23 
-27 
-.19 
2 
1 
2 
1 
2 
2 
(b) Sideslip t e s t s  
Configuration I I (EN = 200) I c”P 
I 0*001.5 -0.0063 
-.0064 
-0.0015 
- .mi6 
? 
10 
U ."o 
-P C ._ 
3 
W > 2 .- 
I 
rl 
c 
0 
al 
- 
LL 
c 
c 
11 
. 
12 
t 
0 
0 cu 
tl 
cn 
f cu 
Ln 
I cn 
Ln 
a, 
I 
I4 
3 
rl 
k 
m 
k 
0 

14 
Model 
O W  I 
" K 7  
a 
Figure 3.- Longitudinal c h a r a c t e r i s t i c s  of models with f laps  a t  
0' i ief lect ion.  p = oO. 
c 
c 
a 
o o o a o c  
d 
5 
d 
% 
d u 
k 
0 
E: 
0 
d 
r 
cd 
d 
k 
$ 
n 
a3 
W 
16 
.. 
e e  
e e  
e e  
e e  
D 
0 
8 
I- 
f 
c 
32 
. 
0 
0 
0 
A 
h 
ts 
18 
J 
0 
E 
0 
e 
. 
c 
Y 
. 
0 
Q o  
I 9  
c 
t * -.. 
a- 
. a .  --a :a- : :.a : :a. :aa 
a a a. a a. a a. a a . a .  a 0 aaa a .a. a a  a .  
a. .a .a .a a a a. *a . a a aaa a. 
I *  
. 
0 0 0  
19 
h; It a 
Q 
a 
iJ 
k 0  
O G  
20 
0 0 0 0  
4 
3 
2 
I 
L 
D 
- 
0 
- I  
- 2  
- 3  
21 
- 
0 4 8 12 16 20  24 
a 
(c) Variation of L/D with a. 
Figure 5.- Continued. 
22 
0.. .. 0 .  0. .  . 0.. . . 
0 .  0 .  ... 0 .  . .. 0 .  0 .  * .  . -: 0 : : :  ... 
0 .  0.. . . . 0 .  0 .  . . 0.. .. 0.. 0 .  
o o n o  
co d- 0 
9 9 
c I I 
5 
. 
w 
c 
4 u 
E u 
ctl 
0 
r: 
0 
* d  
c 
h a 
W 
. 
. 
n 
n U : 
b V 
0 
23 
+ IO 
0 0  
I 
24 
m m m  ma 
m m m  -2 m m m m  m m m  
ma e m m  e e ma am e m m  ma m m m  em 
ma m m m  e .am ma am 
m e  m a  m a  
0 e ma ma 
m a  m a  m m m  m ^ o m .  
CY 
0 4 a 12 16 20 24 
B 
Figure 7.- Variation of C,, C2, and Cy with f3 for  model 1 with 
lOWer-SWfaCe flaps def lec ted .  6~ = %XI0; a = 7.7'. 
C 
c 
C 
I- 
* 
NASA - Langley Field, Va. L-929 


Static stability and control characteristics of two large-dihedral right triangular pyramid lifting reentry configurations at a Mach number of 3.05

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server