Elton W. Miller, chief of aerodynamics at what is now NASA’s Langley Research Center in Hampton, Virginia, stands in the entrance cone of the Propeller Research Tunnel in this Sept. 9, 1926, photo. In front of the entrance is the Sperry M-1 Messenger, the first full-scale airplane tested in the tunnel.
The Propeller Research Tunnel, or PRT as it came to be known, was only the National Advisory Committee for Aeronautics’ third wind tunnel and the largest one built. The PRT was in fact the largest tunnel built at that time anywhere in the world. Designed to accommodate a full-scale propeller, the throat of the PRT was 20 feet in diameter.
Learn more about the PRT from the report originally published in December 1928.
Image credit: NASA