Study of aerodynamic technology for single-cruise engine V/STOL fighter/attack aircraft

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NASA CONTRACTOR REPORT 166271
Study of Aerodynamic Technology for
Sing1 e-Cruise-Engine V/STOL FighterIAttack Aircraft
Final Report
H. H. Driggers
S. A. Powers
R. T. Roush
Vought Corporation
FOR EARLY DOMESTIC DiSSEMINATION
Because of its significant early commercial potential, this
information, which has been developed under a U.S. Govern-
ment program, is being disseminated within the United States
CONTRACT NAS2-11003
in advance of general publication. This information may be
February 1982 duplicated and used by the recipient with the express limita-
tion that it not be published. Release of this information to
other domestic parties by the recipient sliall be made subject
to these limitations. Foreign release may be made only with
prior NASA approval and appropriate export Licenses. This
legend shall be marked on any reproduction of this informa-
tion in whole or in part.
February 1984
Date for general release

NASA CONTRACTOR REPORT 166271
Study of Aerodynamic Techno1o gy for
Sing1e -Crui se-Engine V/STOL Fighter/Attack Aircraft
Final Report
H. H. Driggers
S. A. Powers
R. T. Roush
Vought Corporation
Dallas, Texas
Prepared for
Ames Research Center
'
Under Contract NAS2-11003
N;tt~onaAl eronautics and
Spuco Adniinistn~tion
Ames Research Center
Moftt:tl kield. Californ~a9 4035

FOREWORD
This study of aerodynamic technology for single-cruise-engine V/STOL
fighterlattack aircraft was Phase I of a research program jointly sponsored by
the National Aeronautics and Space Admini stration and the United States Navy.
Technical Monitors for Ames Research Center weri Mr. D. A. Durston and Mr. W.
P. Nelms, Aircraft Aerodynamics Branch. Navy representatives included Mr. M.
W. Brown, Naval A i r Systems Command and Mr. J. H. Nichols, David W. Taylor
Naval Ship Research and Development Center.
Mr. H. H. Driggers was the Principal Investigator. Mr. S. A. Powers was
responsible for the aerodynamic analysis; Mr. R. T. Roush performed the pro-
pulsion analysis. The following individuals made significant contributions t o
the Phase I study effort:
W. B. Brooks Aerodynamics
T. D. Beatty Aerodynamics
T. C. Dull Mass Properties
K. W. Higham Mass Properties
G. W. Hillman Design
S. E. Orner Aerodynamics
W. B. Sears Aerodynamics
H. E. Sherrieb Aerodynamics
M. K. Worthey Aerodynamics
U.S. Customary Units are used throughout this report. A Metric (SI)
conversion table i s provided i n Appendix I.

SUMMARY
The Vought Series Flow Tandem Fan (SFTF) variable cycle propulsion concept
was integrated into a high performance, single engine V/STOL f ighterlattack
aircraft. The resulting configuration was the focus of a conceptual design
and aerodynamic analysis study emphasizing the identification of aerodynamics
uncertainties. The TF120 study configuration i s a canard delta arrangement
with extensive wing-body blending and three pairs of all-moving vertical
control surfaces t o maintain control i n the post-stall flight regime. Side
inlets feed the SFTF propulsion unit, which exhausts through a two-dimensional
deflecting nozzle. I n the V/STOL mode the forward fan efflux exits through a
i
ventral nozzle; an auxiliary inlet feeds the aft fen and core, which utilize
the aft deflecting nozzle. Exhaust temperature of both streams i s 950'~ for
vertical takeoff, enhancing shipboard compatibility. In high speed flight the
SFTF converts t o an afterburning turbofan cycle which yields exceptionally
high fighter performance.
Estimates of TF120 aerodynamics characteristics were made for Mach numbers
from 0.2 t o 2.4 range. An advanced computer code used i n the analysis pre-
dicted complex interactions between the configuration and deflected control
surfaces. An investigation was made of unconventional control modes, i n which
simultaneous deflections were commanded t o augment a desired single-axis
response whi l e suppressing a1 1 unwanted responses.
Identification of aerodynamic uncertainties was a principal study objec-
tive. All the computer-based estimates were considered inadequate due to
inherent limitations imposed by linear theory as well as anomalies encountered
during the course of the study. Aerodynamic characteristics at high angles of
attack ( including post-stal I), 1a rge control deflections and the close-coupled,
highly integrated and blended configuration were judged beyond the capabilities
available methods. Vought believes a wind tunnel test program i s mandatory t o
supply the data base needed t o validate the TF120 configuration and assess
current aerodynamic analysis methods. A concurrent benefit from the proposed
test program i s that since the TF120 i s only minimally compromised to achieve
V/STOL capability, the aerodynamic configuration i s representative of advanced
CTOL fighters.
SYMBOLS
2
Acceleration in ft/sec
Afterburner
Aerodynamic Center i n fraction of Mean Geometric
Chord
Total jet exit area in ft2
Aj
AOA Angle of attack
Rolling moment coefficient
Drag coefficient
Gross thrust coefficient
Center of gravity
Lift coefficient
Pitching moment
Yawing moment coefficient
Side force coefficient
Drag increment i n pounds
Equivalent nozzle diameter in ft
Propulsion induced suckdown i n lbs
e Oswald span efficiency factor
ECS Environmental control system
FP R Fan pressure ratio
Acceleration of gravity in ft/sec2
Altitude in feet
Moments of inertia about the x, y or z axis,
respectively.
Inlet guide vanes
Constants of proportionality
Mach number
MGC Mean Geometric Chord in feet
Ratio of elevon to vertical f i n deflection
Jet static pressure
2
Jet total pressure in lb/ft
Pressure ratio
Dynamic pressure in lb/ft2
SYMBOLS ( Continued)
q Ratio of elevon to aft ventral f i n deflection
r Ratio of elevon t o forward ventral deflection
R CS React ion control system
S Wing reference area i n ft2
SFC Specific fuel consumption, 1b /hr/l b
SLS Sea level static conditions
ST 0 Short takeoff
T Total jet thrust
TO GW Takeoff gross weight i n Ibs
T4 Turbine outlet temperature
T /W Thrust t o weight ratio
V Velocity, kts
W Airflow i n lblsec
X Downstream distance i n ft
a Angle of attack i n degrees
B Sideslip angle
6 Control surface deflection i n degrees
6 Pressure ratio, PIPSL
Y Flight path angle i n degrees
8 Temperature ratio, TITSL
CONTENTS
PAGE
FOREWORD
SUMMARY
SYMBOLS
CONTENTS
FIGURES
TABLES
1.0 INTRODUCT ION
2.0 AIRCRAFT DESIGN
2.1 DESIGN PHILOSOPHY
2.2 GUIDELINES
2.3 SIZING CRITERIA
3.0 CONCEPT DESCRIPT ION
3.1 AERODYNAMIC CONF IGURAT ION
3.2 PROPULSION INTEGRAT ION
3.3 INTERNAL ARRANGEMENT
3.4 MASS PROPERTIES
4.0 AERODYNAMIC CHARACTER IS T IC S
4.1 DRAG
4.1.1 Minimum Drag
4.1.2 Drag Due to L i f t
4.1.3 Installed Store Drag
4.2 LIFT
4.2.1 Untrimmed L i f t
4.2.2 Aerodynamic Center
4.2.3 Trimmed L i f t
4.3 LAT ERALID IRECT IONAL CHARACTER IST IC S
4.4 USE OF CONVENTIONAL CONTROLS
4.5 UNCONVENT IONAL CONTROLS
4.6 PROPULSION INDUCED EFFECTS