The history of NASA efforts at Ames Research Center in researching the performance and application of thrusting augmentors is reviewed. Current objectives include: (1) parametric description of thrust augmentor application to STOL and V/STOL; (2) the use of theoretical and empirical data; (3) aircraft-augmentor integration; and (4) key design considerations for STOL transport and V/STOL fighter aircraft. Test facilities are described and ejector development and performance are assessed

Koenig, D. G.

English

NASA Technical Reports Server

NASA OVERVIEW
David G. Koenig
Ames Research Center
Moffett Field, Calif. 94035
INTRODUCTION
This review as outlined in figure i will be a summary of effort at Ames
Research Center in researching performance and application of thrusting aug-
mentors. It represents the major portion of the NASA-wide effort in recent
years. Ames got started in 1965 when a large-scale testing program on STOL
application, which was sponsored jointly with the Canadian Government_ was
initiated. The investigation has culminated in the publication of refer-
ences 1 and 2 and the continuing study of the augmentor wing at forward speed
which is presently still funded by the Canadians. The early part of this
effort resulted in using the augmentor wing in the NASA Research Aircraft C8A
which is still being flown. More description of this effort is documented in
references 3 through 6 including Ames in-house research. Specific application
to VTOL was initiated with a joint Air Force NASA program in 1972 and resulted
in Ames 7- by 10-Foot Wind-Tunnel tests, some of which are reported in
reference 7, and a report by NASA currently in preparation. Support of
research in the application of thrusting ejectors to V/STOL will continue
until maximum installed performance has been achieved.
OBJECTIVES
The objectives of this effort have and will continue to be those listed
in figure 2. In all studies, there is a concentrated effort to understand
configuration effects on performance resulting in a general parametric descrip-
tion of thrust augmentors for effective application to STOL and V/STOL. Every-
one tries to obtain as much theoretical as empirical data to apply to this
objective but, at present, the latter is by far more abundant than pertinent
theoretical results. All the objectives in figure 2 are very much related but
must support the principal objective of application or "Key Design Considera-
tions" wh$ch, in our current target, are not only high uninstalled performance
or large thrust augmentation numbers in the laboratory but assuring that these
numbers come from configurations which can be packaged into V/STOL aircraft -
"fighter" or otherwise.
TEST FACILITIES
To study installed performance, Ames will rely on several test facilities
whic1_ take both small- and large-scale models for static and wlnd-tunnel tests.
An installation in the Ames 7- by 10-Foot Wind Tunnel is shown in figure 3.
23
https://ntrs.nasa.gov/search.jsp?R=19800001870 2020-03-21T02:16:21+00:00Z
The configuration is the Air Force design -- reference 7 in a semispanmodel
which yield both static and wind-on data. Figure 4 shows the Amesll-foot
wind-tunnel test section with a semispanmodel of the deHavilland "Cruise Aug-
mentor." This installation allowed study of the performance of the augmentor
wing at high subsonic speeds. The Large-Scale Static Test Stand is shown in
figure 5 with the Ameswind tunnels shownin the background. An additional
building is nowbeing located to the right of the stand but will not interfere
with operation of the test stand. Figure 6 shows the de Havilland fuselage-
mounted ejector model in the 40- by 80-foot wind tunnel. For this model the
ejector is powered by a J-97. More will be said about the configuration and
the test results by a later speaker. An updated data reduction system and a
high pressure air supply is being added to the latter two facilities.
An additional facility, the 80- by 120-foot wind tunnel will be ready for
use in three years and should be included in plans for developmental testing.
It will share power systems with an "overhauled" 40 by 80 foot wind tunnel and
will be a through-flow no-return part of the complex extending out the right
(t_ward the northwest) of the 40- by 80-foot wind tunnel shownin figure 5.
Also seen in figure 5, a large full-scale model or aircraft can be tested on
the test stand, put on a trailer and transported to the 40 by 80 or 80 by
120 foot wind tunnel over a very short distance.
EJECTORPERFORMANCEEVALUATION
Through testing both at small- and large-scale numbers on augmentor per-
formance are summarized in figure 7. This collection of data has been shown
previously and parts of it published last year in reference 8. The gross
augmentation is defined as the ratio of total actual thrust to the actual
thrust of primary nozzle. For evaluating the primary thrust, this actual or
measuredvalue must often be derived from the thrust based on isentropic
expansion from the nozzles using correction factors representative of nozzle
efficiency. The mixing length is the average distance from the primary
nozzles to the end of the diffuser and is nondimensionalized by the average
nozzle width t. (Total nozzle area divided by ejector throat length.) The
lower performance ejectors are either STOLapplication for low entrainment or
were poorly optimized.
rt Ks certainly possible that both the values for the XFV-12Aand the
de Havil]and model (fuselage ejector) can be or already has been further opti-
mized. The use of _/t as a parameter in the figure was an arbitrary choice
but was used for manyyears as a meansof "collapsing" data for slotted and
simple lobed nozzles to the faired lines. The spread in performance for given
mixing lengths illustrates the effects of both types of entrainment and mixing
as well as ejector configuration differences.
The challenge in sorting out the differences in ejector performance shown
in figure 7 must be met by evaluating someof and more than the parameters
listed in figures 8, 9, and I0 which have been separated into geometric, per-
formance, and operating definition, respectively. For geometry, one can
organize these into nozzle, shroud or diffuser, and general configuration.
24
What is, obviously, absent is the type or specific design or "scheme" such as
whether or not the configuration promotes strictly turbulent mixing or is the
entrainment accomplished through shear alone. For each ejector configuration,
the performance evaluated, using someor all of the parameters listed in
figure 9, must be documentedfor as manyof the geometric parameters as pos-
sible. Tests must be madeat the operating conditions (parameters) in fig-
ure ]0. A primary problem in the experimental study of the potential of a
given ejector concept is not just the complexity of the hardware required but
the amount and sophistication of the instrumentation needed to document this
performance and operation.
INVESTIGATIONSAT LARGESCALE
Manyof the operating or test conditions can be obtained only by install-
ing the ejector in an aircraft configuration and testing it both statically
and at airspeed. It seemsessential to investigate installation effects with
a particular ejector configuration even though the isolated ejector is still
not completely optimized in order to insure that all performance parameters
have been evaluated properly. To do this, a significant amount of basic
research using smaller models (cold or hot air supply) and analytical develop-
ment should be continued vigorously, however, large-scale testing is a valuable
tool in evaluating installation effects.
Current experimental and theoretical programs are being carried out on the
V/STOLfighter configuration shownin figures ii and 12. The NASAXV-12A
static tests are complete and someof the results will be discussed here. The
wind-tunnel tests on a large-scale model of the wing root or fuselage-mounted
ejectors (installation shown in fig. 6) were completed in February and will
be discussed in this workshop by Mr. D. C. Whittley. Installation of tile
short diffuser or Alperin ejector will be studied using the fighter design
shown in figure 12.
[t is intended that this be a parallel program with large-scale tests on
a RALS pills deflector nozzle configuration. This latter program will be
initiated next February with test in Ames 40- by 80-Foot Wind Tunnel on the
STOL configuration having blowing over a deflected flap plus spanwise blowing.
All of these models will be powered by J-97's. As shown in figure 12 an
alternate configuration might be the combination of an ejector with the VEO or
vectored direct thrust in the rear.
A more detailed sketch of the ejector fighter configuration is shown in
figure IB. Except for the strakes, it is a configuration that is meetin_
requirements of the Navy and Air Force supersonic fighter, particularly for
subsonic high maneuverability needs. A strake is a natural spot to place the
ejector but the ejector diffuser must be short, or, if not, diffuser scheme
must be designed into the aircraft such that it can be retracted for cruise.
For the [atter option, a primary emphasis on the complete model tests will be
one of integration into the aircraft mission both mechanically and aerodynam-
ically. The program is being started with both NASA and Contractual work
using isolated and small-scale ejector models. This will be followed by
25
large-scale static tests (at the scale of the complete model) using the com-
plete ejector propulsion system. And only after acceptable installed ejector
performance is obtained statically will the complete model be tested.
CONCLUDINGREMARKS
AmesResearch Center will continue to take the lead in NASA's effort to
explore several applications of the thrusting ejector. Figure 14 lists areas
in future effort where research and development will be supported both in-house
and contractually. It seems evident that the major application will be to the
V/STOL fighter and our large-scale testing is currently organized on this
basis. However, it is felt that other applications such as that of control
thrustors, and augmenting circulatory lift in the STOL mode should be contin-
ually considered.
REFERENCES
,
.
,
.
.
.
.
°
Koenig, David G.; and Falarski, Michael D.: Wind-Tunnel Investigation of
the Thrust Augmentor Performance of a Large-Scale Swept Wing Model,
NASA TM X-73,239, 1978.
Garland, D. B.; and Whittley, D. C.: Thrust Performance of a Large Scale
Augmentor Wind Tunnel Model NASA CR-152170, 1978.
Whittley, D. C.; and Cook, W. L.: Comparison of Model and Flight Test
Data for an Augmentor-Wing STOL Research Aircraft. Presented at the
AGARD Flight Mechanics Symposium on "Flight/Ground Testing Facilities
Correlations," June 9-12, 1975.
Farbridge, J. E.: The Transonic Multi-Foil Augmentor-Wing, AIAA
Paper 77-606. Presented at 1977 AIAA/NASA Ames V/STOL Conference, ]977.
Aiken, Thomas N.: Aerodynamic and Noise Measurements on a Quasi-Two
Dimensional Augmentor Wing Model with Lobe-Type Nozzles, NASA
TM X-62,237, 1974.
Aiken, Thomas N.; Falarski, M. D.; and Koenig, David G.: Aerodynamic
Characteristics of a Large-Scale Semispan Model with a Swept Wing and
an Augmented Jet Flap with Hypermixing Nozzles, NASA TM X-73,236, 1979.
Brown, S. L.; and Murphy, R. D.: Design and Test of Ejector Thrust Augmen-
tation Configurations Paper No. 19, AGARD CP-143, April 1974.
Aiken, Thon_is N.: Thurst Augmentor Application for STOL and V/STOL,
NASA TM X-73,241, 1977; also AIAA Paper 77-605, 1977.
26
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DUCT AREA RATIO Ad/A n
THROAT AREA RATIO
DIFFUSER AREA RATIO
At/An
Ae/A t
EXIT AREA RATIO Ae/A n
MIXING LENGTH _/t"
NOZZEL TYPE
NOZZEL ASPECT RATIO, NAR h/t
NOZZEL PITCH, NP p/t
TURNING ANGLE, OT
VENTILATION
AUGMENTOR ASPECT RATIO
Figure 8.- Thrust augmentor geometry parameters.
34
DUCT PRESSURE LOSS, _P/P (PIN--PouT)/PIN
NOZZEL VELOCITY COEFFICIENT, C V (T/mnVji) SHROUD OFF
TURNING EFFICIENCY, _TT T/ToT
CIRCULATION LIFT COEFFICENT, CLi CL--CL POWER OFF
GROSS AUGMENTATION, _G TSHROUD ON _/'FSHROUD OFF
ISENTROPIC AUGMENTATION, _1 (T/mnVJI)SHROUD ON
ENTERTAINMENT RATIO ms/mn
NET AUGMENTATION, _N _gG--(msVoo)/TSHROUD OFF
Figure 9.- Thrust augmentor performance parameters.
35
DUCT MACH NUMBER, M D
NOZZEL PRESSURE RATIO, NPR (PN)TOTAL/Poo
NOZZEL TEMPERATURE RATIO, (Tn)TOTAL/Too
THRUST LOADING, T/S (Tn)a/S
VELOCITY RATIO, Vo_/Vj Voo/(VjaOR VJ I )
THRUST COEFFICIENT, Cj (Tn)a/qS
Figure I0.- Thrust augmentor operating parameters.
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