The National Advisory Committee for Aeronautics (NACA)'s first wind tunnel,Located at Langley Field in Hampton,VA,was an open-circuit wind tunnel completed in 1920. Essentially a replica of the ten-year-old tunnel at the British National Physical Laboratory, it was a low-speed facility which involved the one-twentieth-scale models. Because tests showed that the models compared poorly with the actual aircraft by a factor of 20, a suggestion was made to construct a sealed airtight chamber in which air could be compressed to the same extent as the model being tested. The new tunnel, the Variable Density Tunnel was the first of its kind and has become a National Historic Landmark.
