The Eight-Foot High Speed Tunnel, also known as Eight-Foot Transonic Tunnel, was a

wind tunnel Wind tunnels are large tubes with air blowing through them which are used to replicate the interaction between air and an object flying through the air or moving along the ground. Researchers use wind tunnels to learn more about how an aircraft ...

located in Building 641 of

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

Langley Research Center The Langley Research Center (LaRC or NASA Langley), located in Hampton, Virginia, United States of America, is the oldest of NASA's field centers. It directly borders Langley Air Force Base and the Back River on the Chesapeake Bay. LaRC has fo ...

Hampton, Virginia Hampton () is an independent city (United States), independent city in the Commonwealth (U.S. state), Commonwealth of Virginia in the United States. As of the 2020 United States Census, 2020 census, the population was 137,148. It is the List ...

. It was a

National Historic Landmark A National Historic Landmark (NHL) is a building, district, object, site, or structure that is officially recognized by the United States government for its outstanding historical significance. Only some 2,500 (~3%) of over 90,000 places listed ...

. The tunnel was completed in 1936 at a cost of $36,266,000. Because of its high speed and

Bernoulli's principle In fluid dynamics, Bernoulli's principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in static pressure or a decrease in the fluid's potential energy. The principle is named after the Swiss mathematici ...

, 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 (RC), also called reinforced cement concrete (RCC) and ferroconcrete, is a composite material in which concrete's relatively low tensile strength and ductility are compensated for by the inclusion of reinforcement having hig ...

with walls up to 1 ft (0.3 m) thick. This resulted in an "

igloo An igloo (Inuit languages: , Inuktitut syllabics (plural: )), also known as a snow house or snow hut, is a type of shelter built of suitable snow. Although igloos are often associated with all Inuit, they were traditionally used only b ...

-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 (M or Ma) (; ) is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a boundary to the local speed of sound. It is named after the Moravian physicist and philosopher Ernst Mach. : \mathrm = \frac ...

up to 0.75. It was powered by an electric motor. It was repowered to 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 . 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 The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. At , the speed of sound in air is about , or one kilometre in or one mile in . It depends strongly on temperature as w ...

. 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 (or transsonic) flow is air flowing around an object at a speed that generates regions of both subsonic and supersonic airflow around that object. The exact range of speeds depends on the object's critical Mach number, but transonic ...

range. The tunnel was deactivated in 1956, when a new tunnel was built near it. The wind tunnel was used for critical tests that validated the

area rule The Whitcomb area rule, named after NACA engineer Richard Whitcomb and also called the transonic area rule, is a design procedure used to reduce an aircraft's drag at transonic speeds which occur between about Mach 0.75 and 1.2. For supersonic ...

for the design of

supersonic aircraft A supersonic aircraft is an aircraft capable of supersonic flight, that is, flying faster than the speed of sound (Mach number 1). Supersonic speed, Supersonic aircraft were developed in the second half of the twentieth century. Supersonic airc ...

. 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 taken out of service in 1956. It was declared a

in 1985. and In 2011, Building 641, which housed the tunnel, was demolished. The landmark designation was withdrawn in 2014, and it was removed from the National Register of Historic Places. There are additional photographs of the wind tunnel in the

Historic American Engineering Record Heritage Documentation Programs (HDP) is a division of the U.S. National Park Service (NPS) responsible for administering the Historic American Buildings Survey (HABS), Historic American Engineering Record (HAER), and Historic American Landscapes ...

collection.HAER photographs of the wind tunnel

References

External links

* * *
Aviation: From Sand Dunes to Sonic Booms, a National Park Service ''Discover Our Shared Heritage'' Travel ItineraryNASA Langley Cultural Resources: 8-Foot High Speed Tunnel
{{National Register of Historic Places in Virginia Buildings and structures in Hampton, Virginia Langley Research Center Wind tunnels Tunnels completed in 1936 Historic American Engineering Record in Virginia Former National Historic Landmarks of the United States Former National Register of Historic Places in Virginia

See also

References

External links