Eight-Foot High Speed Tunnel
Encyclopedia
The Eight-Foot High Speed Tunnel, also known as Eight-Foot Transonic Tunnel, is a wind tunnel
at NASA
's Langley Research Center
in Hampton, Virginia
. It is a National Historic Landmark
.
The tunnel was completed in 1936 at a cost of $36,266,000. Because of its high speed and Bernoulli's principle
, the pressure in the test section is much lower than that in the rest of the tunnel. This required a structure that could withstand an inward force due to the pressure difference. Instead of steel construction, it was built from reinforced concrete
with walls up to 1 ft (0.3 m) thick. This resulted in an "igloo
-like" structure at the test section. The wind tunnel was designed as a single-return tunnel capable of moving air at speeds up to a Mach number
up to 0.75. It was powered by an 8000 hp electric motor. It was repowered to 16000 hp to give Mach number 1 capability in 1945. In 1947, the speed was increased to a Mach number of 1.2 with the installation of a contoured nozzle. In 1950, a slotted-throat test section was installed, and it was repowered to 25000 hp.
Because it was the first continuous-flow high-speed tunnel, this tunnel was a landmark in wind tunnel design. This meant it could operate almost indefinitely to produce a high-speed airstream approaching the speed of sound
. And it was large enough to accommodate large-scale models and even full-scale aircraft sections.
In 1950, the tunnel was the first in the world to be modified to incorporate a slotted throat design. This revolutionary design gave researchers their first accurate data on airframe performance in the transonic
range. The tunnel was deactivated in 1956, when a new 8 feet (2.4 m) tunnel was built near it.
The wind tunnel was used for critical tests that validated the area rule
for the design of supersonic aircraft
. This said that the fuselage of the aircraft should narrow at the wings and expand at their trailing edges. This resulted in "wasp-waisted" aircraft.
The tunnel was deactivated in 1956 and closed in 1996.
It was declared a National Historic Landmark
in 1985.
There are additional photographs of the wind tunnel in the Historic American Engineering Record collection.
Wind tunnel
A wind tunnel is a research tool used in aerodynamic research to study the effects of air moving past solid objects.-Theory of operation:Wind tunnels were first proposed as a means of studying vehicles in free flight...
at NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
's Langley Research Center
Langley Research Center
Langley Research Center is the oldest of NASA's field centers, located in Hampton, Virginia, United States. It directly borders Poquoson, Virginia and Langley Air Force Base...
in Hampton, Virginia
Hampton, Virginia
Hampton is an independent city that is not part of any county in Southeast Virginia. Its population is 137,436. As one of the seven major cities that compose the Hampton Roads metropolitan area, it is on the southeastern end of the Virginia Peninsula. Located on the Hampton Roads Beltway, it hosts...
. It is a National Historic Landmark
National Historic Landmark
A National Historic Landmark is a building, site, structure, object, or district, that is officially recognized by the United States government for its historical significance...
.
The tunnel was completed in 1936 at a cost of $36,266,000. Because of its high speed and Bernoulli's principle
Bernoulli's principle
In fluid dynamics, Bernoulli's principle states that for an inviscid flow, an increase in the speed of the fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy...
, the pressure in the test section is much lower than that in the rest of the tunnel. This required a structure that could withstand an inward force due to the pressure difference. Instead of steel construction, it was built from reinforced concrete
Reinforced concrete
Reinforced concrete is concrete in which reinforcement bars , reinforcement grids, plates or fibers have been incorporated to strengthen the concrete in tension. It was invented by French gardener Joseph Monier in 1849 and patented in 1867. The term Ferro Concrete refers only to concrete that is...
with walls up to 1 ft (0.3 m) thick. This resulted in an "igloo
Igloo
An igloo or snowhouse is a type of shelter built of snow, originally built by the Inuit....
-like" structure at the test section. The wind tunnel was designed as a single-return tunnel capable of moving air at speeds up to a Mach number
Mach number
Mach number is the speed of an object moving through air, or any other fluid substance, divided by the speed of sound as it is in that substance for its particular physical conditions, including those of temperature and pressure...
up to 0.75. It was powered by an 8000 hp electric motor. It was repowered to 16000 hp to give Mach number 1 capability in 1945. In 1947, the speed was increased to a Mach number of 1.2 with the installation of a contoured nozzle. In 1950, a slotted-throat test section was installed, and it was repowered to 25000 hp.
Because it was the first continuous-flow high-speed tunnel, this tunnel was a landmark in wind tunnel design. This meant it could operate almost indefinitely to produce a high-speed airstream approaching the speed of sound
Speed of sound
The speed of sound is the distance travelled during a unit of time by a sound wave propagating through an elastic medium. In dry air at , the speed of sound is . This is , or about one kilometer in three seconds or approximately one mile in five seconds....
. And it was large enough to accommodate large-scale models and even full-scale aircraft sections.
In 1950, the tunnel was the first in the world to be modified to incorporate a slotted throat design. This revolutionary design gave researchers their first accurate data on airframe performance in the transonic
Transonic
Transonic speed is an aeronautics term referring to the condition of flight in which a range of velocities of airflow exist surrounding and flowing past an air vehicle or an airfoil that are concurrently below, at, and above the speed of sound in the range of Mach 0.8 to 1.2, i.e. 600–900 mph...
range. The tunnel was deactivated in 1956, when a new 8 feet (2.4 m) tunnel was built near it.
The wind tunnel was used for critical tests that validated the area rule
Area rule
The Whitcomb area rule, also called the transonic area rule, is a design technique used to reduce an aircraft's drag at transonic and supersonic speeds, particularly between Mach 0.75 and 1.2....
for the design of supersonic aircraft
Supersonic aircraft
A supersonic aircraft is designed to exceed the speed of sound in at least some of its normal flight configurations.-Overview:The great majority of supersonic aircraft today are military or experimental aircraft...
. This said that the fuselage of the aircraft should narrow at the wings and expand at their trailing edges. This resulted in "wasp-waisted" aircraft.
The tunnel was deactivated in 1956 and closed in 1996.
It was declared a National Historic Landmark
National Historic Landmark
A National Historic Landmark is a building, site, structure, object, or district, that is officially recognized by the United States government for its historical significance...
in 1985.
There are additional photographs of the wind tunnel in the Historic American Engineering Record collection.
External links
- NASA Langley Research Center, 8 feet (2.4 m) High Speed Wind Tunnel, 641 Thornell Avenue, Hampton, VA: 22 photos, 1 drawing, 30 data pages, and NASA Langley Research Center, 8 feet (2.4 m) Transonic Pressure Tunnel, 640 Thornell Avenue, Hampton, VA: 9 additional photos, at Historic American Engineering Record
- Aviation: From Sand Dunes to Sonic Booms, a National Park Service Discover Our Shared Heritage Travel Itinerary
- NASA Langley Cultural Resources: 8-Foot High Speed Tunnel