ⓘ Bell XV-3
The Bell XV-3 is an American tiltrotor aircraft developed by Bell Helicopter for a joint research program between the United States Air Force and the United States Army in order to explore convertiplane technologies. The XV-3 featured an engine mounted in the fuselage with driveshafts transferring power to two-bladed rotor assemblies mounted on the wingtips. The wingtip rotor assemblies were mounted to tilt 90 degrees from vertical to horizontal, designed to allow the XV-3 to take off land like a helicopter but fly at faster airspeeds, similar to a conventional fixed-wing aircraft.
In the XV-3 first flew on 11 August 1955. Although he was limited in performance, the aircraft successfully demonstrated concept development, performing 110 transitions from helicopter mode to the airplane in the period from December 1958 to July 1962. The program of the XV-3 ended when the remaining aircraft was severely damaged in a wind tunnel accident on 20 may 1966. Data and experience from the XV-3 program are key elements used to successfully develop the bell XV-15, which subsequently opened the way for V-22 Osprey.