[3] In 1923, Langley engineer Fred Weick, suggested NACA build a wind tunnel with a 20 foot diameter throat, capable of speeds up to 100 miles per hour in order to perform full-scale propeller tests.

Built using two 1000-horsepower diesel submarine engines, and an 8-blade, 27-foot diameter fan, the Propeller Research Tunnel was capable of pushing air in a 20-foot stream at 110 miles per hour.

[2] The PRT remained operational until it was demolished in 1950 when NACA needed a place to build their 8-foot Transonic Pressure Tunnel.

NACA was also able to test full scale propellers to find a blade shape that maximized efficiency and performance where previous designs had failed.

[3] Data collected in the PRT was used heavily in the design of many World War II planes including the Boeing B-17 Flying Fortress, Consolidated B-24 Liberator, and the Douglas DC-3.