Evidence exists that wind tunnels have been used for thesis research at the Institute since at least 1896, and by the Fall of 1933 several tunnels already had become available for instruction and development testing when Dr. Jerome C. Hunsaker returned to MIT both to Head the Department of Mechanical Engineering and to be in charge of its "course" in Aeronautical Engineering. The Institute's tunnels of that time all had closed circular throats, diameters of four, five, and seven and one-half feet, and were of open return type of construction. In particular the five foot tunnel served for student instruction and theses. Both it and the seven and one-half foot tunnel were operated by Ward-Leonard control systems and were fitted with advanced self-balancing, six component wire balances. All tests were at very moderate speeds corresponding to both Mach and Reynolds numbers far below those for the aircraft of those times (e.g. the Boeing B-9 and Model 247, Curtiss Hawk, or Douglas DC-2). In that setting the need for a better tunnel was clearly recognized, and is recorded in the even earlier pleading for funds by Prof. C. Fayette Taylor in several of his reports to the President.
A major step towards a new and substantial tunnel was made in 1935 upon crystalization of a design. The final concept and most of the design fundamentals were the responsibility of Dr. H. Peters. The suggestion was made to construct a closed single return circuit with a closed elliptical operating test section seven and one-half by ten feet, all enclosed within an outer steel shell that would allow pressurized tunnel operations and thus achieve a variable Reynolds number capability. The driver was a 2,000 horsepower, pole changing induction motor and controllable pitch thirteen foot diameter fan. Measurements of forces and moments over adjustable pitch and yaw ranges were to be made with a rigid pyramidal support balance with remotely indicating, self balancing, mechanical beams. Construction of the tunnel was approved by the Corporation on 12 May 1937 and the product was to be called the Wright Brothers Memorial Wind Tunnel.
The initial cost was approximately $230,000, slightly half of which came from funds solicited by Dr. Hunsaker from various "friends" (of MIT, of Orville Wright, and of aviation). Gifts totalling $92,000 were received from a donors list that included Vincent Bendix, V.A.M. Burden, Godfrey L. Cabot, E.A. and C.W. Deeds, Edward Mallinckrodt Jr., G.J. Mead, F.B. Rentschler, H.N. Slater, and the Curtiss-Wright Corporation. A $15,000 grant from the Carnegie Corporation was specifically designated for measuring equipment. The remainder came from investment income ($4,000), facility charges for development tests that were sponsored by industry ($59,000), and the Eastman Building Fund ($60,000).
In addition, there were donations of operating and measurement equipment, for motor systems to drive model propellers as well as system installation, by the Curtiss-Wright and United Aircraft Corporation, including cost contributions of about $30,000. This provided proper flow simulations during stability and control testing.
The preliminary design was completed by Dr. Peters with the assistance of two young staffers, Joseph Bicknell and James B. Kendrick, and the balance design was carried out by John R. Markham with the aid of W.H. Cook Jr. The official consultants included C.S. Draper for instrumentation, O.C. Koppen for model requirements, J.S. Newell for stress analysis, S. Ober for the propeller fan, M. Rauscher for the pressure system, and E.S. Taylor for vibration. Construction contracts were awarded to Jackson & Moreland for engineering and supervision, Pittsburgh-Des Moines Steel Co. for the outer shell, Westinghouse for electrical equipment, McCreery Theriault for the building, and Fairbanks Morse for the balance. The structure was filled with water for pressure certification on 12 August 1938, and despite the late arrival of balance and fan parts on 7 September, and though still incomplete, the tunnel was dedicated and operated only five days later during the Fifth International Congress of Applied Mechanics. The speakers at the ceremony were Griffith Brewer of the Royal Aeronautical Society and George W. Lewis from the NACA. By 31 May 1939 the circuit had been pumped up twice for operation both under pressure and at vacuum conditions.
Bicknell had received the SM Degree from Course 16 in 1937, joined the NACA Langley center, and returned in 1939 at the request of Professor Shatswell Ober to work at the Wright Brothers Facility. He arrived only four days before Peters left for Germany at the start of World War II. Professors Markham and Ober were in charge of the facility at that time.
The first dozen years of operation included extremely heavy demands from industry for design development testing during the Second World War. The original pressurized capability was set aside and two shifts per day was the normal procedure. The charge algorithm was based on actual costs, normal overhead, and facility improvement. The latter included projects such as a separate student wind tunnel ($51,000) and a transonic wind tunnel and Building (17A) ($135,000), the tunnels being demolished in 1961 and 1964 respectively.
A number of famous aircraft were tested for industry during the '40 and '50 decades (e.g. Sikorsky, Grumman, Republic, Consolidated-Vultee, Chance Vought). Pressure operations were concentrated at 2.5 atmospheres absolute and test velocity was virtually always held to 125 mph, with the motor-fan system in second speed. Pressure limitations in part were related to practical pumping times; dryers were required to avoid wet air during compression, and too rapid decompression led to condensation. Third speed was avoided as a result of the excessive noise, but when necessary was timed to meet the 10 minute breaks between classes! Fourth speed was also avoided due to gyroscopic forces on the fan blades which prevented pitch changes while running. Noise proved to be very severe in fourth speed, and was responsible for a glass block window arrangement that was installed for the classroom (33-206) in the adjacent Guggenheim Building.
During the late 1950's, a sliding nozzle block, blow-down, transonic wind tunnel that was designed for aeroelastic studies was supported by the facility both financially as well as by the tunnel circuit itself (in the role of a two atmospheres source pressure tank). The shared operations continued for about eight years. In the mid 1960's then Director Professor Bicknell initiated aerodynamic evaluations of ground structures, specifically for several campus areas [the Green Building (1965), the Center for Advanced Engineering Study (1966), and the Calder "Sail" for McDermott Court], while continuing general aviation testing (e.g. General Aviation, Helioplane).
On Bicknell's retirement in 1969 Frank H. Durgin assumed the responsibility for day to day operations and began a serious attempt to broaden the match of the tunnel's capabilities to the needs of the civil engineering and architectural communities. Beginning in 1972 the facility took on the major undertaking of both wind tunnel simulations and on-site measurements to explain window failures being experienced in the new John Hancock Tower across the Charles River Basin in Boston. Following some success, an initial design evaluation assignment was awarded to establish the wind effects on the facade and at ground level for the Sears Tower in Chicago, and this occupied the latter years of the 1970's, along with a number of other ground studies (radome housings, the Battery Park and Trade Center Towers area at the southern tip of Manhattan, antenna configurations, galloping power transmission lines, and tall structures in Cincinnati, Columbus, Orlando, Toledo, and Boston). Special lectures and demonstrations of wind tunnel practice were conducted each semester for the School of Architecture, the presence of graduate Research Assistants from Civil Engineering became a regular feature, and Professor David P. Hoult scheduled smokestack plume pollution research studies for the Mechanical Engineering Department. For several years Professor Normal D. Ham, and then Professor Eugene E. Covert, served as Directors. Ham carried out helicopter rotor studies, and with Paul Bauer developed a unique gust generating system for general wind tunnel applications. During Covert's tenure the use of the tunnel for building and environmental testing continued. One particularly interesting program was conducted for the Atlantic Richfield Oil Company, Prudhoe Bay, Alaska operation. The purpose was to shape the underside of a building on stilts so that prevailing winds would clear the snow from beneath the building, rather than allowing drift accumulations. The program was successful, but nearly a decade later a call informed Mr. Durgin that the area was filling with snow. It turned out that the rule prohibiting vehicle parking under the building was not being enforced! Upon strict enforcement, the wind again cleared the area of snow. Still another interesting concept involved sensing stall acoustically, and was carried out by Bolt Beranek and Newman in a series of tests.
In 1979 Professor Judson R. Baron was appointed Director and an aeronautical priority was reestablished in parallel with the ongoing wind aerodynamics studies. The Fairchild Republic Company became a major user of the facility and successively developed a number of aircraft (the Saab/Fairchild [SF340] twin engine transport, the USAF Next Generation Trainer [T46A], a drone vehicle, a forward swept wing fighter prototype, and several advanced preliminary design configurations). The Digital Equipment Corporation provided a new computation system for automated data acquisition, and with special support grants from Fairchild, the facility acquired a new test control console, a complete reconfiguration of the original balance system that allowed the installation of modern strain gage sensors for all six components, computation system peripherals, and encouragement to pursue recertification for pressurized operations with either air or a heavy gas. On 30 January 1984, during "routine" development testing of a joint Boeing/Fairchild model (an ASW version of the SF340), pressure operations over the range from 0.5 to 1.5 atmospheres were carried out for the first time in three decades to examine Reynolds number effects, and have since been extended to 2.0 atmospheres.
In recent years Faculty research interests generated long range studies of unsteady airfoil flow fields (Prof. E.E. Covert), jet engine inlet-vortex behavior (Prof. E.M. Greitzer), aeroelastic tests of unducted propeller fans (Prof. E. Crawley), and panel methods for tunnel wall interaction effects (Prof. J.R. Baron). Industrial testing has ranged over auxillary propulsion burner units, helicopter antenna pods, and in-flight trailing cables, as well as new concepts for roofing attachments, a variety of stationary and vehicle mounted ground antenna configurations, the aeroelastic dynamics of Airport Control Tower configurations for the Federal Aviation Authority, and the less anticipated live tests in Olympic ski gear, astronauts' space suits for tare evaluations related to underwater simulations of weightless space activity, racing bicycles, subway station entrances, and Olympic rowing shells for oarlock system drag comparisons. Baron retired in the Fall of 1989 and Covert became Director once again.
In over a half century of operations the work has been recorded in several hundred theses and more than one thousand technical reports.
