Bell X-22

The Bell X-22 is an experimental vertical takeoff and landing aircraft built by Bell Aerosystems for the United States Navy and Air Force, first flown in 1966 with four tiltable ducted propellers mounted on wings that could rotate from a horizontal position for vertical takeoff and hovering flight to a more conventional forward-facing position for efficient cruising flight. Intended to explore whether a tilting-duct design could combine helicopter-like vertical flight with fixed-wing-like cruising speed and range, it was one of several vertical takeoff and landing research aircraft built and flown by American manufacturers during the 1960s, and while it did not lead directly to a production aircraft, its flight test data contributed to the broader body of research into vertical and short takeoff and landing propulsion concepts.