DEN-Tt_ ---

X-652

AT TRANSONIC AND LOW

SPEEDS

_rankA. Lazzeroni

Research Center

Field, C al-Z_.

FIDENTIAL

ADMINISTRATION

May 1962

!

i|

- _,_ .._ ._ __. .... -_

_._-_5__ _%

_ -.- -_-___-_ __ .-. .

- __ -- .. __

Y..

iJ

..... ww. --_ ..............

°

_ _ _ . °v.. _ .

-" _'GN_fDE_TD/ ..............

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

TECHNICAL M_ORANDUM X-652

i , , , , ,

EXPERIMENTAL INVESTIGATION OF A DISK-SH_ REENTRY

CONFIGURATION AT TRANSONIC AND LOW

SUPERSONIC SPEEDS*

By Frank A. Lazzeroni

SUMMARY

An investigation has been made to determine the static longitudinal

and lateral-directional aerodynamic characteristics of a disk-shaped

reentry configuration. The model had an elliptic profile with a maximum

thickness-diameter ratio of 0.325. The tests vere conducted to maximum

angles of attack and sideslip of 22 ° over a Mach number range from 0.95

to 1.50 at a Reynolds number of 3.5×10s-

The basic disk was longitudinally unstable about a center of gravity

at 40 percent of the diameter from the leading edge. Addition of a canopy,

vertical stabilizing surfaces_ and horizontal control surfaces provided

static longitudinal and directional stability through the angle-of-attack

range at Mach numbers above 1.0. At a Mach number of 0.95, a slight

pitch-up occurred at angles of attack above 5° .

INTRODUCTION

The design of a space vehicle capable of reentering the earth's

atmosphere at satellite speed and above involves many compromises to

cope with the problems of aerodynamic heating, stability and control,

vehicle performance, etc. As a result, both lifting and nonlifting vehi-

cles have been considered and the resulting shapes have been extremely

varied (e.g., refs. 1 through 4). For manned flight, the lifting-type

vehicle is especially attractive. One such vehicle receiving consider-

ation is the lenticular shape. This vehicle would enter the atmosphere

at a high angle of attack (50 ° to 90o ) to produce a high drag and reduce

heating; then, as the velocity decreased and the high heating period

• ' *Title Unclassified

CONFIDENTIAL

2

r

.... _ _ v

CONFIDENTIAL

passed, the angle of attack would be reduced and the vehicle would enter

a gliding phase. It is intended that the vehicle would be landed by

conventional techniques.

It was recognized that control in low-speed flight could be a problem

for the unorthodox disk-shaped vehicle. Accordingly, a study was con-

ducted in the Ames 12-Foot Pressure Wind Tunnel of this phase of the

flight regime of such vehicles (refs. _ and 6). Out of this study two

particular shapes appeared sufficiently promising to warrant some study

at supersonic speed and were the subject of an investigation at a Mach

number of 2.2 (ref. 7). These shapes were circular in plan form with

elliptic cross sections and incorporated control and stabilizing surfaces

at the rear of the vehicle and a canopy. One model had a thickness-to-

diameter ratio of 0.325 and a symmetrical section and was the subject of

an investigation at a _ch number of 3-5 (ref. 8). The present report

presents the results of an investigation with a model having this same

geometry at Mach numbers from 0.95 to 1.50 and a Reynolds number of

3._×i06 based on the plan-form diameter. Previous test results for uncam-

bered circular disks have sho_n stable trim points at high angles of

attack at transonic and supersonic speeds (refs. 8, 9, and i0). Lower

angles of attack are more appropriate to this speed regime for such

vehicles so the present study was confined to angles of attack less than24 o .

NOTATION

The results are presented in standard coefficient form. Lift and

drag coefficients are referred to the wind axes; all other aerodynamic

coefficients are referred to the body axes. All moments are referred to

a point in the longitudinal plane of symmetry on the major axis of the

elliptical cross section 0.40 diameter aft of the leading edge. The

reference area in each case is the plan-form area of the particular

configuration (including the area of the horizontal control surfaces for

the complete model).

drag

qSdrag coefficient,

drag at zero lift

cD

%o

CLlift

lift coefficient,qS

side-force coefficient,side force

qS

C_ rolling-moment coefficient, rolling momentqSd

CONFIDENTIAL

Cm

Cn

pitching-moment coefficient, pitching moment

qSd

yawing-moment coefficient,yawing moment

qSd

d diameter

Llift-drag ratio

M free-streamMach number

q free-stream dynamic pressure

Reynolds number, pVd

r radial distance from center of model

plan-form area of model (including horizontal control surface area

for the complete model)

t

dmaximum thickness-to-diameter ratio

V free-stream velocity

y vertical distance from chord plane

angle of attack, measured with respect to the chord plane

angle of sideslip

deflection of horizontal control surface, positive downward (see

fig. l)

p free-streamdensity

free-stream viscosity

dCL_

\-gJJ o° tos°lift curve slope between _ = 0° and 5 °, per deg

dCm

\d-_LJ CL=O to o.l

pitching-moment curve slope from CL = 0 to 0.i

CONFIDENTIAL

CONFIDENTIAL

cy_

cz6

Cn__=0 0 to 5 °

derivatives with respect to

per deg

_, between _ = 00 and 5°,

APPARATUS AND MODEL

The experimental investigation was conducted in the Ames 6- by 6-Foot

Supersonic Wind Tunnel which is of the closed-circuit variable-pressure

type with a Mach number range from 0.7 to 2.2. A dimensional drawing of

the model is presented in figure i, and a photograph of the model is shown

in figure 2. The basic shape was circular in plan form with a thickness-

to-diameter ratio of 0.32_ and an elliptic profile, the shape being gener-

ated by revolving# about the minor axis, the elliptic sections defined by

the coordinates given in table I.

The horizontal control surfaces were thick flat plates extending

radially from the trailing edge of the basic disks as shown in figure 1.

The horizontal control surfaces consisted of two inboard and two outboard

surfaces with a total area which was 25 percent of the plan-form area of

the basic disk. The hinge lines of the controls were normal to radial

lines of the disk at the centers of the respective controls.

The vertical stabilizing surfaces were two constant thickness tri-

angular shapes with rounded leading edges swept back 65 °. Each vertical

surface was 5-1/2 percent of the plan-form area of the basic disk, giving

a total exposed area of ll percent of the plan-form area.

Details of the model canopy are shown in figure 3. A small fairing

at the rear of the models accommodated the support sting. An internal

six-component strain-gage balance was used to measure the forces andmoments on the model.

TEST AND PROCEDURES

Measurements of the static longitudinal aerodynamic characteristics

of the model were made at Mach numbers from 0.95 to 1.50 for a Reynolds

number of 3.5 million based on the diameter of the model. The angle-of-

attack and angle-of-sideslip ranges were from -6° to +22 ° and the

horizontal control surface deflections were from -20 ° to +5 °.

CONFIDENTIAL

w_g • .........

CONFIDENTIAL

Stream Variations

Surveys of the stream characteristics of the wind tunnel have shown

that essentially no stream curvature exists in the vicinity of the model

and that the axial static-pressure variations are less than 1 percent of

the dynamic pressure. Therefore, no corrections for stream curvature or

static-pressure variations were made in the present investigation. The

data have been adjusted to take account of the stream angles in the

vertical plane along the tunnel center llne measured in these surveys.

Support Interference

Interference from the sting support on the aerodynamic characteristics

of the model was considered to consist primarily of a change in the pres-

sure at the base of the model. Accordingly, the static pressures within

the balance cavity of the model were measured and the drag data were

adjusted to correspond to free-stream static pressure within the cavity

and on the base of the annulus of the model fairing around the sting.

Tunnel-Wall Interference

The effectiveness of the perforations in the wind-tunnel test section

in preventing choking and in absorbing reflected disturbances at low super-

sonic speeds has been established experimentally. Unpublished data fromthe wind-tunnel calibration indicate that reliable data can be obtained

throughout the Mach number range of the tunnel if certain restrictions

are imposed on the model size and attitude. The configuration used in

the present investigation complied with these restrictions and shadowgraphobservations of the flow around the model substantiated the fact that no

choking or reflected disturbances were present for the test conditions

reported herein.

RE SULT S

The results of the experimental investigation are presented in

figures 4 through 9. Longitudinal aerodynamic characteristics of the

basic disk are presented in figure 4. Lift and pitching-moment curve

slopes and drag at zero lift are shown as functions of Mach number in

figure 5 for the basic disk. Data from M = 0.25 to M = 0.9 were obtained

from reference 6 while data at M = 2.2 were obtained from reference 7.

Longitudinal and lateral-directional aerodynamic characteristics of the

complete model with canopy, vertical surface, and horizontal control

CONFIDENTIAL

6 CONFIDENTIAL

surfaces are presented in figures 6 and 7, respectively, while the lift

and pitching-moment curve slopes and drag at zero lift as a function of

Mach number are summarized in figure 8. The lateral-directional stability

derivatives are summarized in figure 9. As with the basic disk, the

summary data from M = 0.29 to 0.90 and at M = 2.2 for figures 8 and 9

were obtained from references 6 and 7, respectively.

With the center of moments 0.4 diameter aft of the leading edge, the

slope of the pitching-moment curve for the basic disk (figs. 4 and D)

had a positive value at low lift coefficients and decreased to zero or

became slightly negative at higher lift coefficients. When the canopy_

vertical surfaces, and horizontal control surfaces at zero deflection

were added to the basic disk, the pltching-moment curves had a stable

slope throughout the Mach number range of the present investigation

(figs. 6 and 8). Ul_ward (negative) deflection of the horizontal controls

reduced the static longitudinal stability at Mach numbers of 0.95, 1.O0,

and 1.10 (figs. 6(a), (b), and (c)), and neutral or slightly unstable

conditions were present for certain lift coefficients, depending on the

Mach number. At Mach numbers of 1.30 and 1.50 (figs. 6(d) and (e)) the

pitching-moment curves with the controls deflected were more linear than

at the lower Mach numbers, and stable trim conditions were evident to

near maximum L/D. The effects of control deflection on L/D were small

for the Mach number range of the investigation.

The yawing-moment and side-force data presented in figure 7 indicate

that the vertical surfaces maintain their effectiveness to high angles

of sideslip throughout the transonic speed range at angles of attack of

0° and 5°. The rolling-moment data indicate that the vertical surfaces

provide a negative increment of dihedral effect at low angles of attack

in the transonic speed range. The summary of results in figure 9 for

the complete model shows a reduction of directional stability with

increasing Mach number in the supersonic speed range and a negative

dihedral effect at transonic speeds for an angle of attack of 0 °. The

dihedral effect was positive throughout the speed range for an angle of

attack of 5° •

A

6

1

4

Ames Research Center

National Aeronautics and Space Administration

Moffett Field, Calif., Mar. 6, 1962

CONFIDENTIAL

7

REFERENCES

lo

•

.

.

Staff of Langley Flight Research Division (compiled by

Donald C. Cheatham): A Concept of a Manned Satellite Reentry

Which is Completed With a Glide Landing. NASA TM X-226, 1959-

Foster_ Gerald V.: Exploratory Investigation at a Mach Number of

2.01 of the Longitudinal Stability and Control Characteristics of

a Winged Reentry Configuration. NASA TM X-175, 1959.

Eggers, Alfred J., Jr., and Wong, Thomas J.: Re-entry and Recovery

of Near-Earth Satellites, With Particular Attention to a Manned

Vehicle. NASA MEMO I0-2-58A, 1958.

Grant, C. Frederick: Importance of the Variation of Drag With Lift

in Minimization of Satellite Entry Acceleration. NASA TN D-120,

1959.

5. Demele, Fred A., and Browns,n, Jack J.: Subsonic Longitudinal

Aerodynamic Characteristics of Disks With Elliptic Cross Sections

and Thickness-Diameter Ratios From 0.225 to 0.425. NASA TN D-788,

1961.

. Demele_ Fred A., and Brownson_ Jack J.: Subsonic Aerodynamic

Characteristics of Disk Re-entry Configurations With Elliptic Cross

Sections and Thickness-Diameter Ratios of 0.225 and 0.325. NASA

TM X-566, 1961.

7- Lazzeroni_ Frank A.: Aerodynamic Characteristics of Two Disk Re-entry

Configurations at a Mach Number of 2.2. NASA TM X-567, 1961.

Q

•

i0.

Demele, Fred A., and Lazzeroni, Frank A.: Effects of Control Surfaces

on the Aerodynamic Characteristics of a Disk Re-entry Shape at

Large Angles of Attack and a Mach Number of 3-5. NASA TM X-576,

1961.

Mugler, John P., Jr., and 01stad, Walter B.: Static Longitudinal

Aerodynamic Characteristics at Transonic Speeds of a Lenticular-

Shaped Reentry Vehicle, NASA TM X-423, 1960.

Jackson, Charlie M., Jr., and Harris, Roy V., Jr.: Static Longi-

tudinal Stability and Control Characteristics at a Mach Number of

1.99 of a Lenticular-Shaped Reentry Vehicle. NASA TN D-514, 1960.

CONFIDENTIAL

CONFIDENTIAL

TABLEI.- COORDINATESOFSURFACEOFMODEL[All dimensions in inches]

T

d

A

6

I

4

t/d = 0.325

r ±y r ±y

0

.25

.50

-75i.OO

1.25

1.5o

1.75

2 .o0

2 -25

2.50

2.753.00

3.25

3.5o

1.950

1.948

1.943

1.935

1.923

i .908

1.888

3.60

3.754.00

4.25

4.50

4.75

5.oo

i .560

1.522

i.453

i -376

1.290

1.191

1.0781.865

1.8381.808

1-773

1.7331.689

1-639

1.584

5.25

5-50

5.6O

5-70

5.80

5-90

5 -956 .oo

.944

•779

•7oo.6o9

.499

.355

.251

CONFIDENTIAL

.... _.u - ° -

...... _--: ._ - ..." ..........

COIVE ]_D _,v_ I AI_

c-

c°_

c

0

c

E

¢-°_

._1

c

! I ,I_

C:_--0 a)

U.

o

0

/ _

co_!i

0

o

.rH

%,d

r-t_3

o.r-tm

i1)

.r-tA

I

,t-t

h0.r-I

C01_ II?t_IT Y.AL

A

6

1

4

Figure 2.- Photograph of model.

A-28583

CONFIDFaTfIAL

CONFIDENTIAL

< y

,t- .75 -_

×

JSs oo,our

Body I C.L.

J1.5

I3,25

2.15

I.75

\

11

p'J__

x y

0 0

•o5 +.z45•25 .220

•50 .345i.oo .5451.50 .690

2.Z5 •75O2.50 .7353. O0 •655

3.25 .55o3 *40 .41o

3.50 o

Profile

X Z

0 0

.50 .29o1.00 .520

1.50 .680

2.15 .750

2.50 .68o3.00 .425

3.5o o

Section A

Z

0 O.4O5.I0 .400

•15 .395.20 .380

•25 .365

•30 .340

•35 .295.40 .235

•45 0

Section C

y Z

0 0.245.lo .245.20 .240

•25 .235•30 .230

•35 .220.40 .205.45 .180•50 .130

•55 o

Figure 3-- Canopy details.

CONFIDENTIAL

12

o

o

o\

,o_

_, "c"-6-- b-0_'-Io \ \_'-' \ O_

_D(D

o

o

_D

(kJ

O

!

cO

I

dI!

o

_D

_J

o

_D

CO

o

o

o

O

o

_H0

0

O]

m %

0

0 __3

o3 r-t

-0

0

0.r-i4__3

4_r..o

!

Z

%

.r--I

A

61

4

CONFIDENTIAL

C0_-F]Z)F_NTZAL 13

o

oo.Z"

LOO_

d

o

o

oL_

0_

d

o

_z

o-")---o-

O_K)- -r

O;L.")

OrO

_'--C

2---45

A

ds i I!

__. _(.._C)_£ .--C---( _ O_ 'I• I,_

01"1 "lfll

__( __...,_ 0 -''_ -0

00"I - N ,.

<)_ --C>--_(_'O_ ..CrICFF O

jc _ )/ g6"O- I_.-LT

_-_i _ 8.

:Oh

idII

v

_ h

-o. \

_. -._\ _ o_.,.. --

"K "_ o,,._

00'1 =N

g6'O =_0

hO OJ --: 0 --: OJ rO _h.I I" I I

_J

E(J

D

d

L)

L) ,-IfJ

- o_

I

O

iL vww lw_ ........ C _,.ii,_i-_-_iT _-k-Ti_TrT_T _T, _ ....

!!l

Itl

_,,.:

i :i

I oO

JJ

ff

//

o

o

o

U

! o

\

\

\

iIIIl

O

o

Sii

r

O

(:3

o

o

\\

li

il

OO

(3

I

._

.r"l

o m

o

_4•r-t 4 nr-t_H

or.-I

OO

q) i1)

_3

4-_,r--I

O.r--I

,el%

E-_

!

hi?,I-4

A6"l

C0I_II?Nlg2:r.AL

CONFIDENTIAL 15

r_ Od -_ O

CO

io

E(.D

,.-.,(..)

0oJ

(.0

o,J

00

0

I

0gI

0

<.D

oJ--" 0

._1cO

0

o

+_

o

o

ts_0",

0

|1

_3

_d0

_J

©

+_

0

•r-I _

r-_

r'-t

m_4-_

r"-I0

4._

0

r'-t

0N

.r-I%0

0

-00

!

',,0

©

hi?°r-'l

CONFIDENTIAL

,_ _"0"-_ )_

0

_a _ "_

_o_

j

_1

o!

II ! !

oJ

o

_DN

0

E

o

0N

CO

0

!

COI

oc_

(,D

0

00

II

Q

.H

O

I

b0.r4

A

61

CONFIDENTIAL

2J

l*i7

A614

_J

C._

0_H

r-t

U

v

(I)

.H

0

I

©

.rd

CO_ED_L

E(D

c_)

oJ

0

c,D

o3 _1

0 It

00i

q

¢D

r_

/CO

O

©

,H

-p

oK)

!

S4

C0KF!D__T.A5

T

CONFIDENTIAL19

OJ

q

._I{_1

0

@,d

r_(3

or.D

I

@

b.O.r-i

CONFIDI_NTIAL

_0 COnfiDENTIAL

Cn

Cz

Cy

Figure 7-- Static lateral-directional aerodynamic characteristics of the

complete model.

A6]

C0_-FiDENTIAL

v

CONFIDENTIAL21

On

.05

04

.05

.02

.01

0 0 °

O 5 °

°°}0 Verticals

A 5 ° off

0

-.01

-.02

.01

0

CZ-.01

-.02

.08

.04

0

-04

Cy-.08

-2o 8 -4 0 4. 8 12 16 20

(b) M= 1.oo

Figure 7-- Continued.

24 28 52 56 40

CONFIDENTIAL

>2 CONFIDENTIAL

Cn

Cz

Cy

.04 i

03.ol _. ._,t.o ¢__Y

-.01 --d

0

rn

ozx

(l

0 o

5 o

o:}]

Verficols

off

.08

-.04-i

-.08 --_

-'2°8 -4 o

!

4 8 12 16 20 24 28

4

!1

i

32 36 40

P

(c) M = l.lO

Figure 7-- Continued.

A

6

14

CONFIDENTIAL

u w _.w

CONFIDENTIAL23

A

i

4

On

Cz

.05

.04

.03

.02

.01

0

-.01

.02

.01

0

-.01

-.02

.08

.04

c_

0 0 °

O 5 °

°°}0 Verticals

A 5 ° off

Cy

-4 0 4 8 12

116 20 24 28 32 36 40

(_) M = 1.3o

Figure 7.- Continued.

CONFIDENTIAL

24 COK_!DE_[TIAL

o5 I j_.04 oo

-- 0

.05 _ A

cl

0 o5 °

0°_}5° Verticalsoff

1I

-'208 -4 0 4 8 12 16 aO 24 28 52 36 40

#

(e) M = 1.50

Figure 7-- Concluded.

A

g

i4

CONFIDE_21AL

25

k

14

r-

\

\\

ii

If1

--%

J

O

O

o

f'IIt1lL

_j

I

/

/

/

-_ OG _t (q

, ," O O

O

B

o

i

i

Ii

iq

L

i

r0

\

O_

o

o- n_

!

!

II

I

i

-%

o_h

O

E,0Jom. •

oJ O

_4

-04

,¢q

i

,O

i

_O

I

f

I

o

Jor_

o

+_,_.r-.I

o_-t

o

o 4_

+_ %

or--I _-4

4j

r--t%0_ O

i1)N

_3

4o

O

%

!

%

bD.r--I

CONFIDENTIAL

E

Ho

o IHt!

°I_ o/ oH

Ji

(

\

p_o 1

II

iI

0::: / "

,_' Od0 0o o.

?o0

o

0ii

m.c

0 0d0o.

0

0

Bi!

AQ_.

o,J0o.

I

¢)

0 o _'II II

/ _ _cI) o

li °

.r.I

\\ I °n_

.r.t

,r.t

(z) _ -oI! |1 []_

k o

o / 4-,¢O

_ _ _O%

.o

4-_,r-.IN

O o0 _ cO 0d ._

0 0 0I" I I

:>

b ,

°_

A

614

COik[FID_]TJ_IAL NASA-Langley, _9_ A-614

,b