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Aerial view of the AMES Research Center, centered on the Unitary Plan Wind Tunnel complex
Photograph courtesy
NASA Ames Research Center (NASA-ARC
AC-38286-2
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Unitary Plan Wind Tunnel, a National Historic Landmark, was a
research facility used extensively to design and test new generations
of aircraft, both commercial and military, as well as National
Aeronautics and Space Administration (NASA) space vehicles, including
the space shuttle. The Unitary Plan Wind Tunnel was created by
the National Advisory Committee for Aeronautics (NACA), parent
agency of NASA. Constructed between 1950 and 1955, this complex
actually contains three wind tunnels. It represents the continual
development of superior aeronautical research facilities after
the end of the Second World War. These research facilities formed
the foundation from which NASA would launch the American effort
to land a man on the moon.
After the construction of the Variable Density Wind Tunnel at
Langley in 1921, NACA built an impressive variety of technical
research facilities upon which the American aircraft industry
was based. These facilities enabled the American aircraft industry
to dominate the skies in both commercial and military aviation.
By 1945, America's lead in the field of aviation seemed to be
evaporating. The technological achievements of the German missiles
and jet aircraft indicated a lag in American aeronautical research.
In 1949, Congress passed the Unitary Plan Act, under which the
Federal government coordinated a national plan of facility construction
encompassing NACA, as well as the Air Force, private industry,
and universities. The Unitary Plan resulted in the construction
of a new series of wind tunnel complexes to support the American
aircraft industry, including the Ames Unitary Plan Wind Tunnel
Complex.
The Douglas FD-1, 1956, tested at Ames Research Center, where the Unitary Plan Wind Tunnel tested America's new generation of aircraft
Photograph courtesy of NASA/AMES, Image A-21303, taken April 5, 1956 |
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Construction of this facility began in 1950-1951 and continued until
1955. Because no one wind tunnel could meet all the demands for
additional research facilities simulating the entire range of aircraft
and missile flight, NACA chose to build the Ames tunnel with three
separate test sections drawing power from a common centralized power
plant. The transonic test section spanned 11 by 11 feet, while the
two supersonic sections were smaller: nine by seven feet and eight
by seven feet. Giant valves 20 feet in diameter supplied air from
one supersonic leg to another. The American West Coast aircraft
industry quickly capitalized on the Ames Unitary Plan Wind Tunnel
Complex. The famed Boeing fleet of commercial transports and the
Douglas DC-8, DC-9, and DC-10 were all tested here; as well as military
aircraft such as the F-111 fighter, the C-5A transport and the B-1
bomber. In addition to aircraft, in the 1960s and 1970s almost all
NASA manned space vehicles including the Space Shuttle were tested
in the Ames Unitary Plan Wind tunnel complex.
The major element of the tunnel complex is its drive system, consisting
of four intercoupled electric motors. The transonic wind tunnel
is a closed-return, variable density tunnel with a fixed geometry,
ventilated throat, and a single-jack flexible nozzle. Airflow is
produced by a three-stage, axial-flow compressor powered by four-wound-rotor,
variable-speed induction motors. For conventional steady-state tests,
models are generally supported on a string. A schlieran system,
one that allows regions of varying refraction in a transparent medium
caused by pressure or temperature differences and detectable by
photographing the passage of a beam of light, is available for studying
flow patterns, either by direct viewing or by photographs. The details
of the larger supersonic tunnel are much the same, except that it
is equipped with an asymmetric, sliding-block nozzle and the airflow
is produced by an 11-stage, axial-flow compressor powered by four
variable-speed, wound-rotor, induction motors. The smaller supersonic
tunnel is a closed-return, variable-density tunnel equipped with
a symmetrical, flexible-wall throat and the sidewalls are positioned
by a series of jacks operated by hydraulic motors.
The Unitary Plan Wind Tunnel, a National Historic Landmark, is also featured in the Aviation History Travel Itinerary. It is located at the Ames Research
Center, Moffett Field, Sunnyvale, California. Moffett Field is
35 miles south of San Francisco. From Highway 101 use the Moffett
Field exit. The Ames Research Visitor Center is open 8:00am to
4:30pm Monday - Friday, you can reach them at 650-604-5000. Admission
is free. There are no tours of the wind tunnels.
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