NASA Technical Reports Server (NTRS) 20000068996: Hyper-X Engine Testing in the NASA Langley 8-Foot High Temperature Tunnel

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by  NASA Technical Reports Server (NTRS)

AIAA 2000-3605
Hyper-X Engine Testing in the NASA Langley
8-Foot High Temperature Tunnel
Lawrence D. Huebner, Kenneth E. Rock, David W. Witte
and Edward G. Ruf
NASA Langley Research Center
Hampton, VA
Earl H. Andrews, Jr.
FDC/NYMA Inc.
Hampton, VA
36th AIAA/ASME/SAE/ASEE
Joint Propulsion Conference
July 17-19, 2000
Huntsville, Alabama
For permission to copy or to republish, contact the American Institute of Aeronautics and
Astronautics, 1801 Alexander Bell Drive, Suite 500, Reston VA, 20191-4344.

AIAA 2000-3605
HYPER-X ENGINE TESTING IN THE NASA LANGLEY 8-FOOT HIGH TEMPERATURE TUNNEL
Lawrence D. Huebner*, Kenneth E. Rock', David W. Witte' and Edward G. Ruf:1:
NASA Langley Research Center
Hampton, VA
Earl H. Andrews, Jr.§
FDC/NYMA, Inc.
Hampton, VA
ABSTRACT NOMENCLATURE
Airframe-integrated scramjet engine tests have 8-Ft. HTT Langley 8-Ft. High Temperature Tunnel
AETB Alumina-Enhanced Thermal Barrier
becn completed at Mach 7 in the NASA Langley
AHSTF Langley Arc-Heated Scramjet Tcst Facility
8-Foot High Temperature Tunnel under the Hyper-X
AOA, ot angle of attack (deg)
program. These tests provided critical engine data as
well as design and databasc verification for the Mach CD Drag coefficient
CL Lift coefficient
7 flight tests of the Hyper-X research vehicle
CM Pitching moment coefficient
(X-43), which will provide the first-ever airframe-
CFD Computational Fluid Dynamics
integrated scramjet flight data. The tirst model
EDM Electro-Discharge Machining
tested was the Hyper-X Engine Model (HXEM), and
ESpT_I Electronically-Scanned Pressures
the second was the Hyper-X Flight Engine (HXFE).
FFS Full Flowpath Simulator (used with
The HXEM, a partial-width, full-height engine that
HXEM)
is mounted on an airframe structure to simulate the
FMS Force Measurement System
forebody features of the X-43, was tested to provide H enthalpy (BTU/Ibm)
data linking flowpath development databases to the H_ gaseous hydrogen
complete airframe-integrated three-dimensional HSM HYPULSE Scramjet Model
flight configuration and to isolate effects of ground HXEM Hyper-X Engine Model
testing conditions and techniques. The HXFE, an HXFE Hyper-X Flight Engine
exact geometric representation of the X-43 scram.jet HYPULSE NASA Langley Hypersonic Pulse Facility
engine mounted on an airframe structure that at GASL, Inc., Ronkonkoma, NY
duplicates the entire three-dimensional propulsion LO 2 liquid oxygen
flowpath from the vehiclc leading edge to the M Math number
vehicle base, was tested to verify the complete N_ gaseous nitrogen
design as it will be flight tested. This paper presents NASA National Aeronautics and Space
an overview of these two tests, their importance to Administration
the Hyper-X program, and the signiticance of their PSC Propulsion Subsystem Control
contribution to scram jet database development. PLC Programmable Logic Controller
P pressure (psi)
q dynamic pressure (psf)
SERN single expansion-ramp nozzle
Sill 4 gaseous silane
* Aerospace Engineer, Hypersonic Airbreathing Propulsion
T temperature (°R)
Branch, Senior Member. AIAA
TPS thermal protection system
Aerospace Engineer.Hypersonic Airbreathing Propulsion Branch,
VFS Vehicle Flowpath Simulator (used with
Member, AIAA
HXFE)
_:AerospaceEngineer, HypersonicAirbreathingPropulsion Branch
._Aerospace Engineer, Assigned tothe Hyper-X Program Office, X-43 experimental flight vehicle designation for
Asst_-iateFellow.AIAA the Hyper-X flight research vehicles
fuel equivalence ratio
Copyright © 2000 by the American Institute of Aeronautics
and Astronautics. Inc. No copyright is asserted in the United Subscripl_s
States under Title 17,U. S.Code. The U. S.Government has a comb facility combustor condition
royalty-free license to exercise all rights under the copyright t total condition
claimed herein for Governmental Purposes. All other rights
freestream condition
are reserved bythe copyright owner.
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American Institute of Aeronautics and Astronautics
INTRODUCTION The tests of the final Mach 7 flowpath in the 8-Ft.
NASA's Hyper-X Program will move hypersonic Hq"I" are part of an overall effort to understand the major
air-breathing vehicle technology from the laboratory to differences between the preliminary flowpath
the flight environment by obtaining data on a hydrogen- development database and the X-43 flight database.
fueled, airframe-integrated, dual-mode, supersonic Following the flowpath development tests, verification
combustion ramjet (scramjet) propulsion system in testing of the engine in the context of a complete flight-
flight. I These data will provide the first flight validation like vehicle flowpath was initiated. Two engine models
of analytical and computational methods and wind and their supporting airframe keel-line simulators were
tunnel test techniques used to design this class of designed and fabricated for testing in thc 8-Ft. HTT at
vehicles. The Hyper-X Program isjointly performed by Math 7 conditions. The first engine is thc HXEM. a
NASA Langley Research Center and NASA Dryden partial-width, full-height representation of the X-43
Flight Research Center. The flight-test prqiect phase of Mach 7 engine. The airframe structure to which the
this program involves the fabrication and flight testing HXEM is mounted is the Full Flowpath Simulator
of three unpiloted, autonomous Hyper-X research (FFS), which consists of a full-length tbrebody and a
vehicles, designated X-43. The first two flight tests will truncated single expansion-ramp nozzle (SERN)
bc conducted at Mach 7, and the third flight will be aftbody. The HXEM/FFS was tested from February
tested at Math 10. These vehicles are fabricated by a 1999 to June 1999. The second engine, HXFE, is a
contractor team led by MicroCraft and including Boeing spare X-43 Mach 7 flight engine currently dedicated to
and GASL Inc.2 ground testing. The HXFE is the only full-width Hyper-X
Thc development of the Mach 7 X-43 engine scramjet engine that will be tested in a ground facility
flowpath and its integration with an airframe are prior to the X-43 flights. The airframe structure to
described in References 3 and 4. A roadmap of the which the HXFE is mounted is the Vehicle Flowpath
Mach 7 ftowpath verification test program is presented Simulator (VFS) and represents a three-dimensional,
in Figure I and involves three engine models in three geometrically accurate forebody and aftbody of the
facilities from NASA Langley's Scram jet Test X-43. The entire 12-foot-tong X-43 propulsion
Complex. 5 The facilities used are the Hypersonic Pulse flowpath (i.e., the entire undersurface of the X-43) is
Facility (HYPULSE), the Arc-Heated Scramjet Test tested inthe 8-Ft. HTI" with the HXFE/VFS. This is the
Facility (AHSTF), and the 8-Foot High Temperature first-ever wind tunnel test of a full-scale, airframe-
Tunnel (8-Ft. H'Iq'). The engines tested are the integrated, scram jet-powered, flight-vehicle, engine
HYPULSE Scramjet Model (HSM), the Hyper-X flowpath at representative flight conditions. The HXFE/
Engine Model (HXEM). and the Hyper-X Flight Engine VFS was tested from August 1999 until Junc 2000.
(HXFE). These facilities and engines allow an This paper presents an overview of the two Hyper-X
integrated test program to isolate and measure the engine flowpath tests performed in the 8-Ft. HTT in
cffccts on engine operability and performance caused by support of Mach 7 Hyper-X engine operability and
geometric-scale, dynamic-pressure, and test-gas performance verification.
differences between tests. These differences, encircled
in Fig. I, exist due to test-technique and facility 8-FOOT HIGH TEMPERATURE TUNNEL
linaitations. The effects of these differences must be The NASA Langley 8-Ft. HTT 6was designed in the
properly accounted for in the design and analysis late 1950's and placed into service in the mid-1960's as
methodologies when using wind tunnel test results as an a facility to conduct aerothermal loads, aerothermo-
integral part of vehicle/engine design. structures, and high-enthalpy aerodynamic research.
8-Ft. HTT The high-enthalpy flow is produced by burning methane
...... HXFE¢io,o./_VoFpsSpts_ _ in air at high pressure in the facility combustor, then
expanding the flow through an eight-lbot exit-diameter
hypersonic nozzle into the open-jet test section. The
high-enthalpy combustion products contain very little
available oxygen; so during the late 1980's and early
1990's, the tunnel was modified with a liquid oxygen
(LO2) injection system to replenish the oxygen
consumed by the methane-air combustion process to
provide an oxygen molar concentration in the test gas
equal to that of air. This oxygen replenishment system,
which became fully operational in 1993, enables the
testing of large hypersonic airbreathing propulsion
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American Institute of Aeronautics and Astronautics
systemastflightenthalpiefrsomMach4toMach7.7 conditions achieved in the tunnel during any given run
TheH-,andSiH4/H2 fuel/ignitionsystemsutilized vary slightly (within 3%) from the nominal test
duringairbreathingpropulsiontestin_werealso conditions both lor similar tunnel setpoint conditions
installeadndbecamoeperationianl1993°.A schematic and as a function of time within the same run.
drawing of the facility for hypersonic airbreathing Facility-to-Model Interfaces
propulsion testing is shown in Figure 2. For these engine tests, a significant number of
subsystems are required. Major subsystem interfaces
with the facility are shown in Figure 3. Certain features
in the model are controlled by the tunnel Programmable
Logic Controller (PLC) system and others are controlled
mooo, by the Propulsion Subsystem Control (PSC) computer,
which has a wind-tunnel specilic version of the flight
i oo o to,
PSC control software. To the extent practical in the
8-Ft. HTT, subsystems for the two engines replicate
"_l_l_" FMS -Air ejector those of the X-43. The ;imilarities and differences of
Model elevator IU_ LiI
Tovse,natck these subsystems are discussed inthis section. Specifics
of each subsystem are subsequently discussed.
_.._l HXFE orHXEM
Figure 2. 8-Ft. HTT schematic for airbreathing engine testing.
Facility Test Conditions
Testing of the engines occurred at two nominal
I _ ............... , ,
conditions corresponding to a low dynamic pressure (for L_)...:7..,.]............ : :
AHSTF data comparisons) and the X-43 flight dynamic r_i:_ ............................. if ....... ';,"='I
lill .............
pressure. The tunnel combustor conditions and
resulting flow parameters are shown in Table I. The
data in the table are calculated based on forebody rake
data that was used to back out the appropriate .... _'1|
freestream conditions in air to provide acomparison to
'_'; +_=
flight parameters. The results indicate that the Mach
C:av_
number, static pressure, and static temperature at flight ill
simulation conditions are within four percent of those c
Controls ...... -_ Purge .... -_ Data
expected for the X-43 flight condition. Exact -----_ Propellants -----_ Cooling .........},_Electrical
duplication of these properties at the same dynamic Figure 3. Hyper-X engine interfaces with the 8-Ft. HTI'.
pressure and total enthalpy as the actual flight is
impossible because the vitiated air in the 8-Ft. Hq"r Fluid Subsystems
contains approximately 18% water vapor and 9% carbon In general, the low pressure components of the X-43
dioxide by mole fraction. Furthermore, the actual test fluid systems were simulated, but facility supply
systems were utilized in placc of the flight high-pressure
Table l: Summary ofSimulated Freestream Conditions for ignitor fuel, coolant, and nitrogen subsystems
8-Ft. HTT Hyper-X Engine Tests and Comparison to Flight (consisting of high-pressure storage tanks, heat
exchangers, and regulator valves in the X-43). The
Flight Actual
Simulation Low q_ addition of fuel, ignitor, and purge lines to the test
Simulation Flight
section was included during the facility upgrades for
Pcomb (psig) 1000 1585 n/a propulsion testing that were discussed earlier.
Currently, all fluid penetrations into the test section are
Tt(°R) 3550 3550 n/a
connected to steel-braided flex lines that are of sufficient
M 6.84 6.92 7.00 length to allow for full injection and retraction of the
p_ (psia) 0.140 0.211 0.204 model into the test section. These fluid delivery
subsystems are located primarily in the model pedestal
q_ (psi') 647 1000 1000
to simulate flight systems. This also provides a simpler
T (OR) 434 423 408 design and last response required by the PSC.
Ht(BTU/Ibm) 1064 1052 1052 The ignitor and hydrogen fuel systems comprise thc
2° ()o,2o.4° 2° propellant delivery system. Flow control is provided by
O_
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groundtestunitsoftheHyper-Xpintel-typmeotorized and includes a controlled shutoff" valve, flow meter, and
controlvalves.Removabvlealvepintelsandventuri
supply pressure transducer that are interlocked to
flowmetersareutilized
to provide precise flow control facility controls to assure that proper water flow is
to both the partial-width HXEM and the full-width maintained. A visual conlirmation of water flow via
HXFE. Each engine utilized separate pintels tomaintain video camera located above the facility diffuser was also
high fuel system mass-flow-rate control/fidelity and required during testing.
possess about the same dynamic characteristics between
the two engine tests. The plumbing configuration,
ignitor/fuel mixing manifold, and pressure
instrumentation replicate the X-43 systems. The ignitor
system uses a 20%/80% silane/hydrogen mixture by
volume for igniting the engine fuel. The ignitor gas is
delivered to the fuel control system from outside the test
pod via double-walled, vacuum-jacketed, steel-braided
flex lines at 1,200 psia, which isapproximately the same
- cwowatlerleajedtisng
as the pressure downstream of the X-43 ignitor high-
edge
pressure regulator. Gaseous hydrogen fuel is delivered
sidewall
from outside the test pod via double-walled, vacuum-
leading /
jacketed, steel-braided flex lines at 1,150 psia, which edges ---_::_
also is approximately the pressure downstream of the
X-43 fuel high-pressure regulator. Figure4. HXEMshowingwaterjetsduringarun(topfrontview).
The nitrogen purge subsystem has a nominal supply
The PSC computer controls the propulsion
pressure of 1,200 psia and is used tbr two primary
functions of the X-43 vehicle management system that
purposes. First, it serves as a safety feature for
are needed for 8-Ft. HT[" testing. This consists of both
supplying an inert purge of the fuel and ignitor lines
hardware and software to perform cowl door actuation
prior to and immediately tollowing a run. These purges
and fuel control functions. The fuel control valves are
are performed by the use of facility-controlled valves
either pre-programmed to perform a timed fuel
that bypass the two motorized control valves. Second,
sequence or operated in an active fuel control mode with
the nitrogen subsystem is used to purge the internal
closed-loop engine pressure feedback. 9 The PSC
cavities of each model. The nitrogen is injected through
computer has a communication interface with the
discretely-placed tubes to displace air inside the model
facility to ensure a proper synchronization of tunnel and
cavity and actively cool certain components that are
engine events, as well as for data synchronization.
susceptible to additional heating and thermal sensitivity,
Pedestal
such as the two motorized fuel control valves, the cowl
The pedestal that supports the model (see upper left
actuator motor, and the Electronically-Scanned Pressure
of Figure 3) consists of a welded I-beam structural
(ESP TM) modules. The nitrogen subsystem also
frame, copper side plates (with access panels), and a
provides pneumatic actuation (regulated to -750 psig)
zirconia-coated leading edge. The aerodynamically-
for all fuel/purge system isolation valves.
shaped pedestal houses the fuel-control system and
Both of the engines have water cooled sidewall- and
model instrumentation and provides model access for
cowl-leading cdgc designs identical to the X-43 flight
internal cavity purging/cooling of the airframe
engines. Water at 900 psia is delivered to three open-
structures and water cooling for the engine leading
loop cooling paths which dump the water overboard
edges. The pedestal is attached to the 8-Ft. HTr force
through small holes on external surfaces to the flowpath
measurement system with angle-of-attack (AOA)
at the mass flow rates expected in flight. Figure 4 shows
spacers. The AOA spacers are bolted to the FMS.
a photograph of the water jets exiting the HXEM during
When the model is tested at the nominal 2° angle of
a tunnel run. (A closed-loop water path was also used
attack, the pedestal is installed directly onto the AOA
during HXEM testing: its location and purpose will be
spacers and bolted into place. The HXFE/VFS was also
described in the HXEM/FFS Model Description part of
tested at two off-nominal angles of attack (0° and 4°).
the paper.) Pressure and flow-rate requirements were
For these orientations, a set of AOA rails were inserted
established from finite element analysis conducted by
between the AOA spacers and the pedestal base to
GASL, Inc., based on worst-case X-43 heating in flight
provide the correct model attitude and a constant
(a more severe condition than was seen in the tunnel).
vertical location in the test section during a run for each
The water cooling subsystem is active for the time that
angle of attack tested.
the model is in the test section (less than 30 seconds)
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American Institute of Aeronautics and Astronautics
Force Measurement System TEST OBJECTIVES
The 8-Ft. HTT's Force Measurement System Ground tests of the HXEM and HXFE are a vital
(FMS) is used to acquire longitudinal aerodynamic part of NASA's overall Hyper-X scram jet engine ground
loads (axial force, normal force, and pitching moment) test program 4. The objectives of these tests are to
on the test articles that are mounted to it. Both the directly support the flight tests and to provide data for
pedestal and the model are metrically attached to the design methods verification, for ground-to-flight and
FMS. The FMS is attached to the facility elevator facility-to-facility comparisons, and to further develop
carriage, which injects and retracts the model assembly ground test techniques. Once completed, the ground
into the test section (see Figure 2). The FMS was test program and flight test will have provided data to
calibrated to provide accurate load-cell output for these link scramjet performance in flight with performance in
three components at expected Hyper-X loads. smaller-scale engine development facilities. This link
Incremental check loading of the three components will be established by conducting tests with multiple
separately or in combination showed that the errors in engine models in multiple ground test facilities in a
the three components are less than 0.50% of the full- manner which isolates differences between tests in a
scale Hyper-X anticipated loads. The primary purpose quantifiable manner. To accomplish this, the HXEM
of the FMS data was to measure the incremental force was designed to be tested in both the 8-Ft. HTT and the
and moment changes due to cowl door actuation and AHSTF (see Figure I). This was done by reducing the
fuel addition/burning. width of the Hyper-X flowpath to a width suitable for
Visual Coverage testing in the AHSTF and by providing the capability to
Visual recordings of the model consisting of vidco, test with the full Hyper-X forebody or a truncated
still photographs, and schlieren images were obtained forebody suitable for testing in the AHSTF.
during testing. Installation and post-run model images Furthermore, the truncated SERN provides a
were recorded using a digital camera between runs to simplified geometry in which to carry out engine
document hardware condition and any potential analysis. These tests, in conjunction with the HXFE
anomalies that may occur. Furthermore, a color tests and the HSM tests, will provide inlormation on the
Hasselblad TM camera was mounted in one of two effect of partial width, lorebody truncation, freestream
positions inside the test section to capture run-time dynamic pressure, and test-media composition on
photographs of the model. Three test-pod video engine performance.
cameras provided real-time control room display and The other main objective of the HXEM test was to
video recording of the models. A camera mounted provide pretest support lk_r the HXFE test that
above the facility diffuser looking upstream at the succeeded the HXEM test in the 8-Ft. HTI'. The
engine area was used to document the cowl actuation majority of model-to-facility installation issues were
event and to visually confirm water-cooling flow and resolved during the HXEM test. A cowl hardware
engine ignition. A second camera mounted above the actuation problem was also identified and resolved
facility nozzle provided a downstream view into the during HXEM testing which directly caused changes
diffuser as a backup view of cowl actuation. The last to the HXFE and the actual X-43 flight engine design•
camera provided a view of the model for documentation Furthermore, the propulsion subsystem control
from injection to retraction. Additional video from hardware and software used to actuate the cowl door and
outside the test pod included a high-speed video used schedule fueling for the HXFE was exercised during
for overall model surveillance and a black-and-white HXEM testing. This provided an opportunity to verify
camera to provide side-view documentation of the runs. and/or modify these systems in terms of both hardware
The schlieren system at the 8-Ft. HTT is limited to (cowl actuation equipment, fuel control valves, and
showing about a two-loot diameter portion of the test associated plumbing and instrumentation) and the
section at a given time; therefore, the system was software (cowl actuation commands and fuel control
positioned prior to" each run to provide flow-structure logic).
images in the regions where information was desired for The objectives of the HXFE test were three-fold.
a given run. These locations included side views near First, the results will bc a major part of the Mach 7
the engine leading edges (to document the forebody propulsion database for Hyper-X. This test included
shock structure and boundary-layer) and near the engine inlet and engine operation with a fully integrated
trailing edge (to document the exhaust plume and forebody and aftbody flowpath with active propulsion
surrounding shock and expansion structure). subsystem control which includes closed-loop engine
Oil-flow visualization techniques and infrared feedback. The database will be used to both correlate
imaging of the external flowpath surfaces of the mode[ with the flight data and compare with the partial-width
were also employed lbr a limited number of runs. HXEM data. Furthermore, data were obtained for two
American Institute of Aeronautics and Astronautics
segmenotsftheflightprofilethathavenotbeentested MODEL DESCRIPTIONS
elsewhedreuetolimitationinsaerodynamwiicndtunnel
Both models were tested inverted from the flight
testingn;amelyth,eforceandmomenintcremendtuseto orientation to facilitate fluid and instrumentation
openingthefull-widthcowlandduetofueladdition. interfaces and to minimize strut interference on the
Thisprovideddatafor comparisownithpreviously
propulsion flowpath caused by mounting the model to
computeadero-propulsiivnecrementussedto define
the facility. Each airframe structure was capable of
vehiclecontrollawsforthescramieptortionof the
scramjet engine installation on the common Hyper-X
flights.Propulsiownindtunnetlestss,pecificalolyfthe
pedestal that is, in turn, attached to the 8-Ft. HTI" force
HXFE,providethebesptossiblveerificatioonfengine
measurement system. They also housed many of the
effectsontheX-43aerodynamtihcsatcanbeobtained
engine subsystems including cowl door actuation and
onthegroundF. urthermorthee,datawillalsoprovide
fluid system hardware. The forebody leading edge
insighitntothepredictivceapabilitieosfavailabCleFD
radius is the same as the X-43, but possesses a larger
codeasndothertoolsusedinthedesignandanalysoisf
angle extending toward the lower surface so that the
airframe-integrastcerdamjefltowpaths.
X-43 carbon-carbon leading edge is unnecessary,
Second,importantcomponenat nd systems
allowing it to be fabricated from solid copper. The
verificatiownasobtainedduringthistestp,rimarilyon increased thickness in the lower surface also allows for
the enginemechanicaalnd thermaldesign,the
easier integration of the structure, hardware, and
associatfeludidsystemasn,dthePSCsoftwareE.ngine
instrumentation required for this test. The section of the
hardwarceomponentthsatwereverifiedincludecowl
tbrebody containing the nose and first ramp surface is
dooractuatiocno,wlandsidewallelading-edcgoeoling, common to both the FFS and VFS airframes. The first
andthestructurainl tegrityoftheengineduringthe
forebody ramp is a copper plate that includes a channel
criticalpartof theflight(frompost-separatitoon
used to accommodate a set of boundary-layer trips.
completioonfthefuelingsequenceA)l.thougmhuchof Differences in the two models are described below.
thefluidsystemhsardwarweasnotidenticatol fight HXEM/FF$
vehiclehardwareea,chsystemattemptetodmimicthe
As indicated previously, the HXEM isapartial-width
flighthardwarienthesensoefbeingabletocheckout
model of the Mach 7 X-43 engine. The propulsion
thesoftwarethatwill beusedtoperformtheengine
flowpath has an inlet flowpath width of 6.6 inches
functionsT.hissoftwared,evelopeadsaversioonfthe
compared to the 16.78-inch width of the actual flight
flightsoftwarec,ontaineaddditionainl terfacepoints
engine. The HXEM inlet, isolator, combustor, and
specifitcothesafetestingofhydrogen-fueelendgineins
internal nozzle are all two-dimensional representations
the8-Ft.
H'I"T. 9 By fullilling the first two objectives, of the Mach 7 flight engine, and the fuel injectors are of
this test reduced the risk to the X-43 Mach 7flights. identical design.
Third, this test furthered the development of The HXEM/FFS model is shown installed in the 8-
technology capabilities that will be required to perform Ft. HTT in Figure 5. The primary feature of the FFS
ground tests of hypersonic airbreathing propulsion was to provide a geometrically-accurate representation
systems that are fully integrated with hypersonic of the Hyper-X forebody.
vehicles. There are important differences in the testing
that has been pertbrmed on engine modules, as
compared to using an integrated engine and vehicle.
Tunnel integration and interfaces are more challenging
when the test is thought of as a tip-to-tail tlowpath
simulation instead of an engine test. The efforts
performed on this test will provide valuable skills and
techniques that can be employed with the testing of a
completely integrated propulsion/airframe system, as
well as interpretation and understanding of the data
from an airframe-integrated scramiet engine (most
notably lorcc and moment increments).
In addition to these objectives, data was also
acquired to understand the flow environment at various Figure 5. Installation image of HXEM/FFS in the 8-Ft. HTT.
places, including the wing-root gap, forebody, and
external nozzle and aftbody at true Mach 7 flight A number of the HXEM/FFS model characteristics
conditions. are identified in Figure 6. The forebody chines were
closed out with aerodynamic wedge blocks to eliminate
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American Institute of Aeronautics and Astronautics
thelargerearward-facisntgepcreatedbyanabrupt HXFE/VFS
terminatioonfthechines.Inletflowfencepsrevented The HXFE is an exact duplicate of the Mach 7
forebodfylowspillageT.heHXEMwastestewdithtwo scramjct engine that will be used on the first and second
forebodcyonfiguratio(nsseethesideviewsofFigure6). X-43 flights. It is intended to be a dedicated ground test
ThefirstconfiguratipolnacedtheHXEMflushwiththe engine but also serves as a flight spare for the program.
FFSforebodysurfaceinordertoallowaflight-like, The HXFE is rigidly attached to the VFS in a manner
fully-developbeodundarlyayertobeingesteidntothe similar to installation in the X-43. The larger width
inlet. Theotherconfiguratiodnivertedtheforebody compared to the HXEM results in increased mass
boundarlyayerby loweringtheFFSforebody0.75 ingestion, aspect ratio, and tunnel blockage. Many
inchest,herebyexposinga boundary-laydeivrersion surfaces on the HXFE are zirconia coated.
duct to better simulate the boundary-layer The inlet/isolator system in the HXFE is fixed once
characteristeicxspectewdhentheHXEMistesteidnthe the cowl door is opened and has been designed for
AHSTFwitha truncatedforebody.Loweringthe sufficient mass capture for the Math 7 test condition. It
forebodycreatedanexposedleadingedgeat the also includes pressure measurements used in the closed-
beginninogftheboundary-ladyeivrersiodnuctw, hichis loop engine feedback to sense combustor-isolator
exposetdosignificanhteatingth; ereforae,closedloop interaction and prevent inlet unstart. The internal nozzle
wateprassagweasemployetod_ictiveclyooltheleading geometrically transitions the Ilow from the combustor to
edge. Whenthe forebodywasin the diverted the external nozzle with sidewall and cowl geometric
orientationb,oundary-laytreiprs(scaledforthenew expansion near the cowl trailing edge to properly
locationandlocabl oundary-layheerightw)ereinstalled represent the exhaust plume development behind the
ontheHXEM.TheHXEMwasisolatefdromtheFFS
cnginc.
byametricgapw, hichwassealewdithafabricmaterial A schematic illustration of the HXFE/VFS
ableto-withstandthehightemperaturtehsatoccur installation in the 8-Ft. HTT is shown in Figure 7. The
duringeachrun.Finallyt,heHXEM/FFwSastestedat entire upper surface of the HXFE/VFS model simulates
thenominafllightangleofattackoftwodegreeasnd the lower surface of the X-43, but was fabricated in such
zerodegreessideslip.TheFFSsurfacepanelswere a way as to minimize cost and still contain relevant
easilyremovedto facilitateservicingby allowing geometric features of the X-43. The model simulates
internaal ccessto modelmountingareass,tructural the complete propulsion ttowpath, including any
supportasn,dinstrumentation. geometry which may affect the flow entering the engine
inlet or interacting with the nozzle exhaust plume.
Hyper-X [orebody Chines Shaded area metr_ toload cells
-_ Metric gap seal ]
14775" - _..._..__
I 1
Boundary -. " Boundary-layer trips
layerimps (diversion conliguralion only) Flat nozzle
_--= 1435'
Full Boundary-Layer Ingestion Configuration HXEM
Inletflow fence Nozzle
\ /t) I !'>":'
Axial load cells _, -rmq-_--T T .__---
Boundary-Layer Diversion Configuration I : _ _ I AOASpocerB _/ ForceMe_ulement System
I J \'\ _lluAlcdceissirurnenta&ti°n _Carriage
Boundary-layer diversion duct exit Front View Side View
Figure 7. Schematic of HXFE/VFS installation in the 8-Ft. HTT.
Figure 6. HXEM/FFS conflgurational details.
A number of unique HXFE/VFS model
The HXEM is a metric engine model, mounted to
characteristics are identified in Figure 8. Three inserts
the FFS by tour metal flexures. Independent axial load
for the boundary-layer trip strip were tested, including
measurements were obtained for the HXEM-only using
a blank strip with no trip devices, the preliminary Mach
two load cells mounted to the FFS asdepicted in Figure
7 trips, and the final Mach 7 flight trips. The side
6. Confirmation of the accuracy of the FMS axial force
chines and the external nozzle surface are machined
component was made by comparing its output with data
from copper plates. The side chines are sectioned in
from the HXEM axial load cells, as well as integration
parts to allow access into the VFS tbr model attachment
of surface pressure distributions for selected tests. This
points, structural constraints, fluid connections, and
independent axial force measurement will also bc used
instrumentation, as well as to minimize the weight of
for comparison with axial force measurements acquired
each section for handling. To address the effect of
during HXEM tests in the AHSTF.
American Institute of Aeronautics and Astronautics
boundary-layheerating
on engine performance, two
configurations for the second and third forebody ramps
were tested. Ramps made of the same AETB-12 TPS
tile that will be used on the X-43 external surface and
copper panels that are more extensively instrumented
were used. The cusp between the external nozzle and
the aftbody chine is replicated by copper ridge plates.
Wing stubs are included to acquire wing-root gap
heating data. Finally, the HXFE/VFS was tested at off-
nominal angles of attack of zero and four degrees to
complement the data taken at the nominal angle of
attack of two degrees and to better examine the design
space for which the pre-flight performance database was
generated. The effects of cowl-door actuation and
fueling under a nonzero sideslip condition were of great
interest to the program; runs were made at one and three
degrees of sideslip.
Rclge p_eces
_c_lxle$ transitionfrom
Forebody nozzbetocusptochine) Ve_ral.fin
Igvnailtvoers/,fuel ventumriotorizfleodw mectoenrst,rol Propulsion subsystem control computer
I': iI lI......A..EPTSB-1I,2le,_,_/1 'HXFE lIe')dernWallrernEoDzzMl-acuIt_eces,i' and manifold and customized software
layer trips - _ -- 2 ..... J _ _ ',
Sect_ned copper platechine - Wing stubs
for gapheating
(gaps_zeootoo3o"!
Figure 8. HXFE/VFS configurationaldetails.
Flight and Flight-Like Subsystems
As previously stated, one of the primary objectives Figure9. Flightorfight-like subsystemsincorporatedin
of these tests was to reduce risk to flight by exercising 8-Ft.HTTHyper-Xenginetesting.
hardware and software in the 8-Ft. HTT that is as close
to flight-like as reasonably possible. Figure 9 presents
the subsystems that were verified, to the extent practical, represented in the HXFE/VFS. Most of the pressures
in these two tests for flight risk reduction. were measured using ESPTM transducer modules;
however, some of the internal engine pressures were
INSTRUMENTATION measured by discrete transducers identical to those on
Both the HXEM/FFS and the HXFE/VFS were the X-43 and monitored bythe PSC computer for engine
control. The surface instrumentation breakdown for
heavily instrumented with surface pressures and
both models is shown inTable 2.
temperatures to better understand the flow physics of
airframe-integrated scramjet operation and to provide
sufficient data to compare with analytical/computational
solutions and other experimental test and flight data. A PORT oI:o o o o o o o o
schematic layout of surface instrumentation on the VFS o oo oo o oooa ooo o o ;_ _,omo_ _ o o o o oo oo
'flowpath surface and HXFE bodyside surface is o • o eo o _ o _o nod ,moo oo fl o 0 o o=
depicted in Figure 10. It is worth noting that all surface 9
instrumentation locations on the X-43 flight vehicles are
STARBOARD
Figure 10. HXFE/VFShodysideflowpathinstrumentationlayout.
8
American Institute of Aeronautics and Astronautics