FU-1

The Vought FU‑1, also known as the V-173 “Flying Pancake,” was an experimental fighter‑interceptor built for the United States Navy in the early 1940s. Developed from Vought’s earlier XP-46 and XF5U concepts, the FU‑1 first flew on 20 September 1942 under the guidance of chief designer Charles H. Zimmerman. Its most striking feature was a flattened, disc‑shaped airframe that combined the wing and fuselage into a single lifting surface, giving the aircraft a very low aspect‑ratio wing and a radius of action that resembled a giant rotor blade. Powered by a 2,000‑horsepower Pratt & Whitney R-2800 Double Wasp radial engine driving two contra‑rotating propellers, the prototype demonstrated exceptional low‑speed handling, short‑takeoff capability and the ability to sustain lift at high angles of attack. Although the FU‑1 never entered production, its unconventional configuration provided valuable data on advanced aerodynamics, control‑surface interactions and prop‑propulsion integration. The project influenced later VTOL and tilt‑rotor research, cementing the FU‑1’s place as a bold engineering milestone that challenged conventional aircraft design during World War II. Only one prototype, serial 38045, was built and later placed on display at the National Air and Space Museum.