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19710010231 · Estimated aerodynamics of all-body hypersonic aircraft configurations

NASA · 1971

Open the PDFPublic domain · NASATechnical Reports

Overview

Estimated aerodynamics of all-body hypersonic aircraft configurations

Pages
·
39
Chapters
·
2

Key points

  • The document presents analyses for estimating the aerodynamics of all-body hypersonic aircraft configurations, specifically a delta planform with an elliptical cone forebody and elliptical cross-section afterbody.
  • The aerodynamic performance is influenced by configuration geometry, particularly the ratio of maximum cross-section to body planform area, which had the strongest effect on performance.
  • Surface temperatures on the lower surface of the all-body configuration are lower than those of higher lift-loading configurations due to inherent low lift loading.
  • Using a canard for trim instead of horizontal fins can reduce trim drag penalties in vehicle stability and control.
  • The study includes semiempirical and theoretical predictions of aerodynamic characteristics compared with experimental data to validate the methods used.
Frequently asked questions
What is the main focus of the document?

The document focuses on estimating the aerodynamics of all-body hypersonic aircraft configurations, analyzing their performance, surface temperatures, and stability.

What shape parameters were investigated in the study?

The study investigated three shape parameters: body leading-edge sweep, the position of the breakpoint between forebody and afterbody, and the ratio of maximum cross-section to body planform area.

How does the configuration geometry affect aerodynamic performance?

Configuration geometry, particularly the ratio of maximum cross-section to body planform area, significantly influences aerodynamic performance, with this parameter showing the strongest effect.

What impact does using a canard have on the aircraft's performance?

Using a canard for trim instead of horizontal fins reduces trim drag penalties, which can enhance overall aerodynamic performance.

What type of data is used to validate the aerodynamic predictions?

The aerodynamic predictions are validated by comparing semiempirical and theoretical results with available experimental data.

APPENDIX

APPENDIX AERODYNAMICS EQUATIONS LIFT sin a + € sin a where

= - 0.355

Cl M < 1.0 Co = 0 irAR - 0.153 BAR M > 1.0 C = linear interpolation with respect to 3 from C = 0 at 3=0 to [0.955-O.35/M)] _ _ Co = e at AR - 0.13 M > 1.0 6 > ± - AR , _ Ft).955-0*.35/M)] , - e INDUCED DRAG C = %C tan a Di L where M < 3.0 j K = 0.25 (1 + M) M M * 3.0 j K = 1.0 M ZERO-LIFT BODY DRAG C = C + CD + CD

DOB D B FB BB

P Body Pressure Drag M < 0.8 { C = 0 DpB 0.8 < M < 1.2 CD = linear interpolation with respect to M from J R pB Cn „ = 0 at M = 0.8 to B P CD M = l pB ' M ^ 1.2 | CD = CD from numerical integration of pressure R R I distribution on body Body Base Drag Cp ep = Cp from Prandtl-Meyer expansion of forebody pressure distribution RA Unless Cp < Cp when, C C PBASE " ?2-D 0.91 M - 0.20 M + 1.51 (From fig. 5, p. 34, ref. 8) Body Friction Drag S / WET\ 1 4- ?l 1 S C/ * BODY. \ REF/ fn - 0 455 M < 0 ' . 8 i FB i \ 0 . ^4 6 7 Y 2 5 8 - J- M 2 1 (logio Re) - (l 4

2 * *o y

where (MAC) BODY 2(.ZTt/Z) Re = P M a and 0 0 0 i A

(I)

BODY CD_ = linear interpolation with respect to M from 0.8 < M < 1.2 R

CD = c at M = o.s to

FB DpB

CD = CD at M = 1.2

FB FB = M * 1.2 { CD™ CD™ from numerical integration of local skin- re rt> friction coefficients on body Body Bluntness Drag

M < 0.8 CD = o

BB CD = linear interpolation with respect to M from 0.8 < M < 1.0 I RR RR CD =0 at M = 0.8 to BB CD = CD at M = 1.0 RR RR L>D DP irr.

NOSE M > 1.0

CD

BB S REF where 1/2

±-\ -4-.3.15

8 1 0 ,0.5 ' " M A X " ' ' " NOSE ( .

'SKIN \1000 ZERO-LIFT FIN DRAG CD F BF where C CD = D Xc X F VERTICAL FINS CANARD HORIZONTAL FINS computed separately by the following equations.

Fin Pressure Drag M < 0.8 { CD = 0 F 0.8 < M < 1.0 CD p = linear interpolation with respect to M from p CD p = 0 at M = 0.8 to CD = C at M = 1 pF °pF '° 5/3 FIN z M = 1.0 C = 3.4 -, cos A u D c pF \c/ , . S FIN T TV FIN REF 1.0 < M < M • CD p = linear interpolation with respect to M from SA P C = C at M = 1.0 to Dpp DpF C at M = M Dpp SA a !_ FIN

> MSA C

D e S FIN REF Fin Friction Drag 1 + 2 - REF .

C = 0.455 DpF 0.467 2 58 - ( l (lo R e ) - l glo where (MAC) FIN Re = P M a, n o ° ° y, Fin Bluntness Drag

M < 0.8 j C = o

DBF 0.8 < M < 1.0 CD = linear interpolation with respect to M from J RC BF.

Cn , = 0 at M = 0.8 to Dr Df

CD = C at M = i.o

BF DBF FIN where 1 2 c o s r 725 cos - r -'^ NOSE REFERENCES 1. Gregory, Thomas J.; Petersen, Richard H.; and Wyss, John A.: Performance Tradeoffs and Research Problems for Hypersonic Transports. J. Aircraft, vol. 2,1965, pp. 266—271.

2. DeYoung, John; and Harper, Charles W.: Theoretical Symmetric Span Loading at Subsonic Speeds for Wings Having Arbitrary Plan Form. NACA Rep. 921, 1948.

3. Lawrence, H. R.: The Lift Distribution on Low Aspect Ratio Wings at Subsonic Speeds.

J. Aero. Sci., vol. 18, no. 10, Oct. 1951, pp. 683-695.

4. Puckett, A. E.; and Steward, H. J.: Aerodynamic Performance of Delta Wings at Supersonic Speeds. J. Aero. Sci., vol. 14, no. 10, Oct. 1947, pp. 567-578.

5. McDevitt John B.; Rakich, John V.: irFlieSA'ero'd.ynamic Characteristics .of, .Several Thick Delta Wings at Mach Numbers to 6 and Angles of Attack to 50. NASA TM XM 62,1960.

6. Jorgensen, Leland H.: Elliptic Cones Alone and With Wings at Supersonic Speeds. NACA Rep. 1376, 1958.

7. Van Dyke, Milton D.: The Slender Elliptic Cone as a Model for Nonlinear Supersonic Flow Theory. J. Fluid Mech., vol. 1, May 1956, pp. 1—15.

8. Love, Eugene S.: Base Pressure at Supersonic Speeds on Two-Dimensional Airfoils and on Bodies of Revolution With and Without Fins Having Turbulent Boundary Layers. NACA TN3819, 1957.

9. Shapiro, Asher: The Dynamics and Thermodynamics of Compressible Fluid Flow. The Ronald Press Co., N. Y., 1954.

10. Koelle, Heinz Hermann: Handbook of Astronautical Engineering. McGraw-Hill Book Co., Inc., 1961.

11. Eckert, Ersnt R. G.: Survey of Heat Transfer at High Speeds. ARL Rep. 189, Aeronaut. Res.

Lab., Office of Aerosp. Res., Wright—Patterson Air Force Base, Ohio, Dec. 1961.

12. Truitt, Robert Wesley: Hypersonic Aerodynamics. The Ronald Press Co., N. Y., 1959.

13. Eminton, E.; and Lord, W. T.: Note on the Numerical Evaluation of the Wave Drag of Smooth Slender Bodies Using Optimum Area Distributions for Minimum Wave Drag. J. Roy. Aero.

Sco., Jan. 1956, pp. 61-63.

Figure 1.- Aircraft configurations, = A 75° 5^/5 = 0.0935 2^/2=0.667 W =500,0001 b GTO Figure 2.- Nominal configuration; all body cross sections are elliptical.

Figure 3.- Body shape parameters

A=75

°

ESTIMATE MACH 0.6 1.3 5.0 0-6 (SHARP LEADING EDGE) lift.

DATA (REF. 6) ESTIMATE SHAPE o D

o

.4 A

o

.3 .2 j I I i 8 12 16 20 a, deg Figure 5.- Effect of shape on lift; M = 1.97.

DATA (REF. 6) ESTIMATE SHAPE O D

o

o

Figure 6.- Effect of shape on induced drag; M = 1.97.

ESTIMATE MACH A =75° 0.6

<] 0

d/b = 2.0 1.3 5.0 .4 .3 .2 .05 .10 .15 C C D~ D(BASE) Figure 7.- Effect of Mach number on induced drag.

O DATA (REF.6) THEORY (VAN DYKE) CROSS SECTION CROSS SECTION .16 d/b = 6, A = 7I.6 = 3, A=76.7° .12 Cp . 0 8 _GL-00.

. 0 4 .25 .50 .75 1.0 0 .25 .50 .75 1.0 y/a, SEMISPAN STATION e Figure 8.- Forebody pressure distribution; M = 1.97, a = O

SECTION A-A

^

^8, DEFLECTION ANGLE ^ (EXPANSION) %/ SECTION A-A Figure 9.- Afterbody-pressure-calculation geometry.

O DATA (REF.6) M=l,97 REYNOLDS NUMBER = 8 x I0 ESTIMATE ALTITUDE = 13,000 ft .12 1 / A = TAN' [7.34(a/b)~' 2] .10 .08 .06 FOREBODY PRESSURE DRAG .04 .02 TURBULENT SKIN FRICTION DRAG i i i i i i I 2 3 4 5 ELLIPSE AXIS RATIO (a/b)

Figure 10.- Comparison of forebody zero-lift drag with experiment; no base drag

is included; CD is based on cross-section area.

TYPICAL FLIGHT PATH NOMINAL CONFIGURATION (1000 q PATH ABOVE M = 2) (WITH Z = 100 ft) .10 PRESENT ESTIMATE O AREA RULE WAVE DRAG (WING APPROX~20 STATIONS) (+BODY SKIN FRICTION) .08 n AREA RULE WAVE DRAG(WING APPROX-10 STATIONS) (+BODY SKIN FRICTION) .06 FIN AND BLUNTNESS AFTERBODY PRESSURE .04 FOREBODY PRESSURE BODY SKIN FRICTION .02 0 4 6 8 10 MACH NUMBER

Figure 11.- Zero-lift drag versus Mach number; CD . is based on theoretical

body plan area.

\ NOMINAL CONFIGURATION A = 75° STT-/S = 0.0935 ITT/I- 0.667 500,000 Ib 8 WGTO = . PQ = 7.0'lb/ft (L/D) MAX

•[

4 — i

y '

i i 1 1 1 1 0 2 4 6 8 10 12 MACH NUMBER

Figure 12.- Effect of Mach number on CL/D)MAX-

(L/D) MAX 1.2 = 0.0935 ITT/I = 0.667 60 65 70 75 80 85 SWEEP (A), deg i i i 9 8 7 6 5 4 3 2 1 FOREBODY ELLIPSE RATIO, Q/b

Figure 13.- Effect of body sweep on (L/D)MAX-

8r (L/D) MAX A = 75°

f'=°

.02 .04 .06 .08 .10 .12 .14 FATNESS RATIO, S-^/S I | i i i | 12 8 6 5 4 3 FOREBODY ELLIPSE RATIO, d/b

Figure 14.- Effect of fatness ratio on (L/D)MAX-

(L/D) MAX A =75° if =0.0935 O .4 .5 .6 .7 .8 .9 BREAKPOINT LENGTH RATIO, l^/l 2 3 4 5 6 7 FOREBODY ELLIPSE RATIO, d/b Figure 15.- Effect of breakpoint length ratio on (L/D)MAX- (L/D) MAX 0 400 800 1200 1600 GROSS TAKEOFF WEIGHT (W ), 1000 Ib G T O i i i 100 150 175 200 225 250 275 BODY LENGTH, ft Figure 16.- Effect of gross takeoff weight on (L/D)MAX; gross body density 7.0 lb/ft .

(L/D) MAX GROSS TAKEOFF WEIGHT - GROSS BODY DENSITY = THEORETICAL BODY VOLUME I 2 4 6 8 1 0 1 2 1 4 16 GROSS BODY DENSITY (p ), Ib/ft G i i i 400 250 200 175 150 BODY LENGTH, ft

Figure 17.- Effect of gross body density on (L/D)MAX> gross takeoff weight

500,000 Ib.

(L/D) MAX A I I I | | | | V 0 3 0 0 0 3500 4 0 0 0 4500 5 0 0 0 5500 6 0 0 0 RADIATION EQUILIBRIUM TEMPERATURE, °R 15.0 5.0 2.0 1.0 .50 .25 .10 BODY NOSE RADIUS, ft Figure 18.- Effect of maximum allowable leading-edge temperature.

A - 5 5 « L E PLANFORM AR = 0.933 X = 0.200 t/C = 0.040 5 r (L/D) MAX

t

0 .05 .10 .15 .20 HORIZONTAL FIN AREA/BODY PLAN AREA

Figure 19.- Effect of horizontal fin size on (L/D)MAXJ maximum leading-edge

temperature = 4350° R.

A = 60° LE PROFILE AR = 1.200 X = 0.400 t/C = 0.040 5 r (L/D) MAX

i

0 0.5 1.0 1.5 2.0 VERTICAL FIN AREA/BODY PROFILE AREA

Figure 20.- Effect of vertical fin size on

maximum leading-edge

temperature = 4350° R.

= 50° A L E

pLAr

AR = 1.675 X = 0.200 t/C = 0.040 5 r MACH ^-6.0

4 _ EZTT i—

12.0 (L/D) MAX 3 - 0 .025 .050 .075 .100 CANARD AREA/BODY PLAN AREA

Figure 21.- Effect of canard size on maximum leading-edge

temperature = 4350° R.

1600 M=I2.0 h= 115,000 ft 0=0° NOMINAL CONFIGURATION A = 75° = 0.0935 X = 0.667 N IOOO X £=180 ft I500 X Figure 22.- Planform temperature contours, °F.

2 8 0 0 LOWER SURFACE UPPER SURFACE 2 4 0 0 ' . 2 0 0 0 LJ OL QL LJ Q .

q = 1000 Ib/ft e = 0.8 8 0 0 TURBULENT BOUNDARY LAYER

T

WEDGE, 8 = 7.65°

a B

10 12 14 16 18 20 22 24 MACH NUMBER

Figure 23.- Surface radiation equilibrium temperature; 25 feet aft of leading

edge.

ALTITUDE, 1 0 0 0 ft 2 4 0 0 2 0 0 0 M = 12.0 1200 X = 25 ft € = 0.8 TURBULENT BOUNDARY LAYER WEDGE, 0 = 7.65° B

f

10 20 30 LIFT LOADING (L/S), Ib/fr Figure 24.- Effect of altitude and lift loading on lower surface temperature.

M = I2 .01 T r ALTITUDE = I40.0OO ft NOMINAL CONFIGURATION BASIC BODY -.02 - BASIC BODY BASIC BODY + HORIZONTAL FINS + HORIZONTAL FINS -.03 - SHT=O° + FLOATING CANARD +FIXED CANARD = -a CA -.04 - L i i i i .05 -5 0 10 15 20 25 a, deg Figure 25.- Longitudinal stability.

M = I2 ALTITUDE = 140,000 ft 'MAX NOMINAL CONFIGURATION (FLOATING CANARD) Figure 26.- Horizontal fin control power.

-.01 - "CG -.02- M = I2 -.03- ALTITUDE = 140,000 ft NOMINAL CONFIGURATION (FLOATING HORIZONTAL FINS) -.04 - L I I I I .05 -5 10 15 20 25

a.deg

Figure 27.- Floating canard control power.

.002 M=I2 ALTITUDE = 119,200 ft .001 a = 10° ~^T-\ > "CG -.001 A = 75° STT/S = 0.0935 -.002 W = 500,000 Ib GTO -.003 .4 .7 .8 .9 BREAKPOINT LENGTH RATIO, Figure 28.- tffect of body shape on stability.

CONFIGURATION ANALYTICAL MODEL I I Figure 29.- Directional stability model.

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Document details

Doc number
·
19710010231
Publisher
·
NASA
Year
·
1971
Pages
·
39
File size
·
1.4 MB
Chapters
·
2