Focke-Achgelis Fa 269
The Focke-Achgelis Fa 269 was a tiltrotor VTOL aircraft project designed by Henrich Focke. Development. Conceived as a single-seat fighter, the Fa 269 project resulted from a design study order issued by the Reich Air Ministry to Focke-Achgelis in 1941. The order called for a local defence fighter which would combine the VTOL capabilities of a helicopter with the speed and economy of a conventional fixed-wing aircraft. A large amount of wind tunnel testing was undertaken, along with work on gearboxes, drives and power-pivoting mechanisms, and a full-scale mock-up  of the aircraft was built to demonstrate the VTOL concept, but much of this was destroyed by Allied bombing raids and all work was shelved in 1944, when Focke-Achgelis estimated that there was little likelihood of a practical prototype being available before 1947. Design. A mid-wing monoplane, the Fa 269 was to have been powered by a single BMW 801 air-cooled radial engine buried in the fuselage behind the cockpit, which was to have driven transverse drive shafts in the leading edges of the fixed wing, the shafts turning three-bladed rotors via synchronised gearboxes. The plane  of rotation of the rotors would have been capable of being swivelled through 80° using angled extension shafts. It was proposed that the Fa 269 would adopt a high angle of attack when at rest using extremely long undercarriage units. For vertical take-off, the rotors would be lowered till their plane of rotation was parallel with the ground. For translation to conventional flight following take-off, the extension shafts were to pivot to the rear, the rotors then behaving as pusher propellers.