The Bell Model 65 ATV was an experimental jet powered VTOL aircraft that successfully hovered and flew level, but never converted between the two.
In 1950 the American Bureau of Aeronautics ran a contest to produce a VTOL fighter. Lockheed's XFV-1 and Convair's XFY-1 were both tail sitting machines, where the entire machine rotated to level flight. Bell preferred a system where the aircraft remained in the same position and the engines rotated. The Lockheed and Convair projects were both cancelled, but in 1952 Bell was given a feasibility study. Bell decided to go one step further and built a low cost test machine. This became known as the Bell Model 65 or ATV - Air Test Vehicle.
The ATV was produced using elements from existing aircraft. The fuselage came from a Schweizer glider. The wings came from a Cessna 170 and were mounted above the fuselage. The helicopter style undercarriage came from a Bell Model 47. Power came from two 1000lb st Fairchild J44 lightweight turbojets, one on each side of the fuselage. There was also a Turboméca Palouste turbo-generator on the back of the fuselage, which provided power to the compressed air system used for attitude controls.
The compressed air was fed to nozzles at the wingtips and tail. The idea was for the aircraft to take off with the jets mounted vertically and the compressed air providing some control. Once the aircraft was high enough, the engines would rotate into the horizontal position and the aircraft would fly normally.
The maiden flight of the aircraft came in January 1954 and saw it successfully hover. The aircraft was damaged a fire in February, but was repaired and a short test programme began. This only saw the aircraft fly for four and a half hours, but did involve hover tests and level flight. However Bell never risked the transition between vertical and horizontal flight. However, the evidence from the short test programme did convince Bell that the idea of a jet powered VTOL aircraft was sound, and helped with the development of the Bell X-14.