Massachusetts Institute of Technology, Wright Brothers Wind Tunnel records

The MIT Wright Brothers Wind Tunnel is one in a series of subsonic wind tunnels which have been used for aerodynamic research at MIT. Completed in 1939, the tunnel is operated by the MIT Department of Aeronautics and Astronautics. It is a closed-return, variable density wind tunnel equipped with a 7.5-foot by 10-foot diameter elliptical test section. Air is sucked through the wind tunnel by a large propeller and blown over a scale model suspended in the test section. The model is suspended from a balance which measures the wind forces acting upon it. By measuring the wind forces acting upon the model, its aerodynamic characteristics may be identified.

The Wright Brothers Wind Tunnel was dedicated on September 12, 1938, at the 5th International Congress of Applied Mechanics. It was named after Orville and Wilbur Wright to commemorate and perpetuate the methods of research and controlled experimentation used in their development of the first successful airplane. Initially the tunnel was used for aerodynamic research on scale models of aircraft and their components, but later research was conducted on scale models of architectural structures as well. MIT built the Wright Brothers Wind Tunnel to replace the existing 4-foot, 5-foot, and 7.5-foot diameter wind tunnels which had become virtually obsolete due to advances in the speed and size of aircraft. The Wright Brothers Wind Tunnel was utilized primarily by the aircraft manufacturing industry, which until the post-World War II period possessed few adequate wind tunnel facilities.

In 1896, as part of his Mechanical Engineering thesis, Albert J. Wells built the first wind tunnel at MIT, a 3-foot diameter square wind tunnel. Eighteen years later, in 1914, Jerome C. Hunsaker of MIT's Department of Naval Architecture and Marine Engineering built a 4-foot diameter square wind tunnel. The wind tunnel was located on Vassar Street in Cambridge. As the main MIT campus did not move to Cambridge from Boston until 1916, the wind tunnel preceded the "new MIT" by two years. The wind tunnel and wind tunnel tests formed the basis for a graduate course in aeronautical engineering in the Department of Naval Architecture and Marine Engineering until 1920.

In 1917, following the entrance of the United States into World War I, the U.S. War Department, Air Service, Engineering Division, McCook Field, Dayton, Ohio, leased the wind tunnel. Among the engineers assigned to the wind tunnel at various times during the lease period were Edward P. Warner, Shatswell Ober, and John R. Markham. Ober and Markham remained involved with MIT's wind tunnels, in one capacity or another, until 1960. In 1921 the lease agreement was terminated though the Air Service continued to support wind tunnel testing at MIT until 1926 with annual grants.

In 1921 Edward P. Warner, Associate Professor of Engineering, replaced Hunsaker's 4-foot diameter square wind tunnel with a 4-foot diameter circular wind tunnel. Simultaneously, a 7.5-foot diameter wind tunnel was constructed to allow testing of larger aircraft. The 7.5-foot wind tunnel was never run at full power because at its maximum speed of 80 mph there was tremendous noise and vibration. From 1920 to 1926 the wind tunnels, and the aeronautical engineering courses, operated under the auspices of the Physics Department. Aeronautical Engineering operated as an independent course at MIT from 1926 until 1939 when the MIT Department of Aeronautical Engineering was established. In the late 1920's the wind tunnels were relocated to the newly constructed Daniel Guggenheim Aeronautical Laboratory on Massachusetts Avenue, and a 5-foot diameter wind tunnel was built for student use.

The increase in size and speed of airplanes during the 1920's and 1930's required the building of a larger, more effective wind tunnel. A proposal for the construction of the Wright Brothers Wind Tunnel was received by the MIT Corporation in 1936, and approved the following year. Funds, totaling approximately $230,000, were obtained from the MIT Corporation, airplane manufacturers, friends of Wilbur Wright, and other groups of interested individuals. During the early years of its operation the Wright Brothers Wind Tunnel was used extensively by the aircraft manufacturing industry to test scale models of their latest aircraft. In 1940, with the addition of equipment donated by the Curtiss-Wright and United Aircraft Corporations, it became possible to test for the aerodynamic characteristics of powered models, an important advance that produced more accurate test results. During World War II the tunnel was in use 24 hours a day testing military airplanes designed by commercial manufacturers for the allied war effort. To meet the needs of continuous operation, a formal Wright Brothers Wind Tunnel staff, consisting of project engineers and shift leaders, was organized under the supervision of Shatswell Ober, Joseph Bicknell, and John R. Markham.

The 7.5-foot wind tunnel, made obsolete by the Wright Brothers Wind Tunnel, was dismantled in 1941 and the 4-foot wind tunnel was used sparingly. In l948 the 5-foot wind tunnel, which used too much power and took up too much space, was closed. Simultaneously, students in course 16.62 (Aerodynamic Laboratory) were required to perform one laboratory exercise using the Wright Brothers Wind Tunnel. To free the tunnel for commercial research a new student wind tunnel was designed and built by the Wright Brothers Wind Tunnel staff. The new student wind tunnel had a 4.5-foot by 6-foot diameter test section, a six-component aerodynamic balance, and special equipment for testing powered models. The wind tunnel was located at the site of the old student wind tunnel in the Daniel Guggenheim Aeronautical Laboratory. It was constructed in 1948 and used until 1961.

When the Wright Brothers Wind Tunnel was built in 1938-1939 it was the state of the art in wind tunnel design and construction. During the next 15 years similar wind tunnels were built in the U.S., and aircraft design methods were developed which eliminated much of the need for wind tunnel testing. Simultaneously, with the advent of jet propulsion, there developed a need to test for the aerodynamic characteristics of jet aircraft as they approached, and then surpassed, the speed of sound. To fill this void the Wright Brothers Wind Tunnel staff designed the Blowdown Wind Tunnel, which was in use from 1952 to 1959. Using interchangeable test sections, and the Wright Brothers Wind Tunnel as a pressure reservoir, the Blowdown Wind Tunnel was capable of being run as either a transonic or supersonic wind tunnel. The aircraft industry and government agencies began to request testing time in the new facilities. Among those who made use of MIT's "new" wind tunnel facility was the Office of Air Research, United States Air Force, which contracted for an investigation of aerodynamics, aeroelastic and stability problems in the transonic speed range.

Although used primarily for aerodynamic tests of aircraft, the Wright Brothers Wind Tunnel was used for other purposes as well. Beginning in the late 1950's, numerous studies of the effects of winds on architectural structures and their environment were conducted in the tunnel. Among the structures tested were the Associated Universities, Inc.'s proposed radio telescope (1957), the Millstone Hill parabolic scanner (1957), the Green Building in MIT's Eastman Court (1965), MIT's Center for Advanced Engineering Studies (1966), and the Northeast Radio Observatory Corporation's proposed radome (1966).

In the early 1960's, as U.S. government agencies and the aircraft manufacturing industry developed their own wind tunnel facilities, use of the Wright Brothers Wind Tunnel for aerodynamic research declined. Since then, it has been used primarily for studies of architectural structures and MIT Department of Aeronautics and Astronautics student research projects.