Today in History – May 27, 1931 – the Langley Full Scale Tunnel was put into service by NASA’s predecessor, the National Advisory Commitee for Aeronautics. The aircraft designers at Langley needed to know more about the effect of a rotating propeller on controllability, interference among aircraft components, and more important, drag penalties due to external struts, wires, slots, and the like. The result was The Full Scale Tunnel: A Depression Bargain! Under the leadership of Smith J. De France, the construction took only fifteen months, at a cost of $900,000. Current replacement value for this wind tunnel has been conservatively estimated at $35,000,000. At the time of its commissioning it was by far the largest wind tunnel ever built, and is still one of the four largest in the world (30 x 60 feet). In its day, it was considered an extremely innovative design because of its double return configuration, and the location of its dual fans. When tests indicated severe drag penalties from external struts etc, all military aircraft went through drag cleanup at the tunnel. After 46 years of use, it was refurbished in 1977 and returned back to good use.

For more information, see the Engineering Pathway’s educational resources on “wind tunnels“, as well as those on aerodynamics, fluid dynamics and aeronautic engineering. For related curricula, visit the Aeronautical Engineering Education or the Mechanical Engineeirng Education communities.