Powered lift

The final rule allows for flight training in single control eVTOL aircraft and for issue by the FAA certain deviations in cases of future technological advancements.

[2] The term is an aircraft classification used by the International Civil Aviation Organization (ICAO) and the United States' FAA: Powered-lift.

The powered rotors of a tiltrotor (sometimes called proprotor) are mounted on rotating shafts or nacelles at the end of a fixed wing, and used for both lift and propulsion.

An important early tiltrotor in the 1950s, was the Bell XV-3, which was one of the first aircraft designs to go from vertical takeoff to horizontal successfully.

The Osprey by Bell Helicopter and Boeing is a twin-engine tiltrotor design that has two turbine engines each driving three-blade rotors.

The tiltwing is similar to the tiltrotor, except that the rotor mountings are fixed to the wing and the whole assembly tilts between vertical and horizontal positions.

Fixed canard and tail surfaces provided lift during transition, and also stability and control in forward flight.

The Sikorsky X-Wing had a four-bladed rotor utilizing compressed air to control lift over the surfaces while operating as a helicopter.

At higher forward speeds, the rotor would be stopped to continue providing lift as tandem wings in an X configuration.

Some have achieved successful transition between flight modes, as the turboprop-powered Convair XFY Pogo did in November 1954.

The transition to forward flight has never been achieved, although the SNECMA Coléoptère took off, hovered and landed vertically, solely on pure jet thrust.

Similar to a coleopter fixed-wing aircraft, the Triebflügel was intended to take off and land on its tail, rotating on the pitch axis after takeoff and acceleration for forward flight.