Abstract: A vertical or short takeoff and landing aircraft (VSTOL) employing three high bypass turbotip fans disposed in the fuselage and faired into the upper surfaces of the wings, and driven by two gas generators to produce vertical lift and transition to cruise flight such that the tripod arrangement for the turbotip fans generates stable powered flight. In the foregoing aircraft the gas generator - turbotip fan is an integrated propulsion system having thrust vectoring devices and gas flow control valved ducts between the two gas generators and the three turbotip fans to provide all lift, control transition and cruise functions, and in which the gas flow system produces variations in bypass ratios for the various modes of operation.