In the Later 1940s, the US Air Force and US Navy became interested in fighters that could take off and land vertically, and therefore do without the long runways of vulnerably land base and expensive aircraft carriers. Turboprop engines, driving contra rotating propeller units seemed to make such types feasible, and in 1951 the navy contracted for a XFO-1 (soon XFV-1) prototype based on the model 081 design. This had a substantial fuselage, mid set wings, and a cruciform tail unit whose four surface each carried a small wheel on its trailing edge. The selected engine was the 7,100-shp YT40-A-14, in which two T-38 turbines each drove a three blade propeller, providing a 1.2/1 thrust/weight ratio. Only the lower rate AT40-A-6 was available for trials, so it was decided to fit the XFV-1 with a temporary fixed landing gear that would allow conventional take off and landing with this engine, Which was not cleared for vertical operation. An unofficial hop was made in December 1953 during taxiing trials, but the first true flight came only in June 1954. The definitive engine was never made available, and the program was canceled in June 1955. 

Propulsion

Performance