Unitary Plan Wind Tunnel
NASA Langley Research Center
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The Langley Unitary Plan Wind Tunnel is a
closed-circuit, continuous-flow, variable-density
supersonic tunnel with two 4-ft by 4-ft by 7-ft test
sections. Typical tests include force and moment,
surface pressure measurements, and flow
visualization of on-and off-surface flow patterns.
Tests involving jet effects, dynamic stability,
model deformation, global surface and off-body
flow measurements, and heat transfer are also
performed.
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Test Section and Performance
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Unitary Plan Wind Tunnel Characteristics
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The Langley Unitary Plan Wind Tunnel (UPWT) is
a closed-circuit, continuous-flow, variable-density
supersonic wind tunnel with two test sections: one
with a design Mach number range from 1.5 to 2.9
and the other with a Mach number range from 2.3
to 4.6. The tunnel is equipped with asymmetric
sliding-block-type nozzles for varying the ratio of
nozzle throat to test section area, thus providing
continuous variation in Mach number during facility
operation. The low and high Mach number test
sections are formed by the downstream contours of
each nozzle. Test sections are nominally 4-ft by 4-ft in cross section by 7-ft in
length. The maximum Reynolds number per foot
varies from 6 x 10 6 to 11 x 10 6 , depending on
Mach number and test section.
The major elements of the facility are the 100,000
hp drive system, 6 centrifugal compressors operated
in varying combinations or modes, dry air supply,
evacuating system, cooling system, and
inter-connecting ducting which produce the desired
run conditions through either of the two test
sections. The tunnel duct circuit can be
circumscribed by a rectangle 263 ft by 210 ft.
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| Mach number |
1.5 to 4.6 |
| Reynolds number, per foot |
0.5x106 to 11x106 |
| Pressure, atmospheres |
- 0 to 10 |
| Temperature, degrees F |
125 to 175 |
| Test section size, feet |
.4 x 4 x 7 |
High-Pressure Air and
Cooling Capability
High-pressure air and cooling water lines are
available at the test section for
connection to model
components.
Missle Research model
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Model Observation
Photographic and video coverage of the test article
is possible through the test section
Schlieren
windows and/or from within each
test section.
Video and digital images of the
model can be
recorded.
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Instrumentation
Force and moment data are measured by
strain-gage balances. The balances are calibrated to
account for first and second order interactions.
Typically each point of force data is computed
on-line from an average of 60 samples recorded at
30 samples per sec. Online plotting routines can be
used to display real time data. Pressure data are
taken with an electronically scanned pressure (ESP)
system that provides high accuracy measurement of
steady-state model and facility pressures at rates up
to 20,000 ports per sec. The system utilizes
modules each containing 32, 48, or 64 individual
transducers that range from ?2.5 psi to 100 psi. Up
to 16 modules and 1024 pressures may be used.
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Data Acquisition and Processing
The standard data acquisition system consists of an
analog-to-digital converter, capable of acquiring
128 channels of analog data (up to 1000 Hz) and
40 channels of digital data. For data analysis, the
facility provides UNIX, Macintosh, and PC
computers. Customer supplied computers can be
networked to the data reduction system if desired.
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Facilities Available to Users
Two model buildup rooms are provided at the
facility for buildup of models. A
calibration area
provides instrumentation and
propulsion air systems
for calibrations that may be
required to quantify
deflection constants and
propulsive tares.
Safety and Design Criteria
Langley's LHB 1710.15 Wind Tunnel
Model System Criteria is the guideline for model
design and fabrication. Model installation and any exceptions to this document must
have the approval of the UPWT Safety Head on a case-by-case basis to assure
personnel and tunnel hardware are not exposed to risk.
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Model Supports
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Test Techniques
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Methods used to support models and probes vary
depending on test requirements. Increased model
attitude is achieved via assorted angular couplings
and offset stings.
The basic model support mechanism is a horizontal
wall-mounted strut assembly capable of forward and
aft motion in the x-direction, a sting support that has
traverse (y) and sideslip (?) motion,
an angle-of-attack (alpha) mechanism that provides
pitch motion, and a roll mechanism. Capabilities
provided are as follows:
| Axial travel, x-direction, in. |
36 |
| Traverse travel, y-direction, in. |
? 20 |
| Sideslip (?) motion, degrees |
? 8 |
| Angle of attack (alpha), degrees |
-15 to 30 |
| Roll motion, degrees |
variable to 310 |
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Flow visualization capabilities in both test sections include Schlieren, colored and UV oil
flow, laser vapor screen, and fluorescent minitufts. Optical based techniques for
measuring pressure and temperature via pressure (PSP) and temperature (TSP)
sensitive paints and model deformation are also available.
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Model mounting mechanism used for majority of tests.Dimensions in feet.
UPWT test section model.
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Global pressures (PSP) for Arrow Wing model.
Orbital Sciences Corporation X-34 model
in test section 1. |
Type of Testing
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Test Request Procedures
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Model in test section 2. |
Developmental tests of virtually every supersonic
military airplane, missile, and spacecraft to have
become operational in the United States inventory
have been per-formed in the UPWT. Most
supersonic aircraft configurations from the National
Supersonic Transport (SST) Program, the Space
Shuttle Program, and the National AeroSpace Plane
were extensively tested in this facility. Current testing
includes programs such as High Speed Research
(HSR), Advanced Technology Demonstrator
(X-33), Small Reusable Booster (X-34), and
Experimental Crew Return Vehicle (XCRV or
X-38).
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The first step of the test process is to submit a test request form. The form can be
filled out electronically or printed for mailing at the
NASA Langley aero Compass website. A posttest questionnaire is also available at
this site. Our customers are
encouraged to provide feedback to the facility for our continuous improvement process.
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