Convertiplane

A convertiplane is defined by the Fédération Aéronautique Internationale (FAI or World Air Sports Federation) as an aircraft which uses rotor power for vertical takeoff and landing (VTOL) and converts to fixed-wing lift in normal flight.

The gyrocopter is similar except that the rotor continues to spin and to generate a significant amount of lift, and so is classed as a rotorcraft and not a convertiplane.

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.

In February 2023, test pilots from the US Federal Aviation Administration (FAA) flew the AW609 tiltrotor for the first time in a pre-Type Inspection Authorization activity.

[6] 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.

[8][9][10] 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.

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

Baynes developed a proposal for his Heliplane, a tiltrotor convertiplane having two tilting wingtip-mounted nacelles containing the engines, proprotor mounting and main undercarriage.

[12] In 1950s the concept gained brief attention in United States as an intended improvement of helicopters, but the experimental McDonnell XV-1 and Bell XV-3 did not enter production.