The Bell XV-15 tiltrotor demonstrator was the much-flown progenitor of today’s Bell-Boeing V-22 Osprey. The XV-15 could take off and land in confined spaces like a helicopter, but fly horizontally with the speed of a fixed-wing airplane.
The VTOL aircraft first flew on May 3, 1977. It differed from earlier tiltrotor concepts in having its engines mounted in rotating wingtip pods, coupled directly to its rotors, rather than in the fuselage. Two modified Avco Lycoming T53-L-13B turboshaft engines rated at 1,550 hp and driving 25-foot rotors powered the XV-15.
Bell built two for demonstrations; one attended the Paris Air Show in 1981. The first XV-15 was destroyed at the Bell plant on August 20, 1992, in a crash in which no one was seriously injured. The second flew for many years longer. After the Osprey was well along in its development, the second XV-15 showed off its VTOL agility by landing on the lawn of the Pentagon in September 1999. In the pre-9/11 security environment, the XV-15 also landed in front of the Capitol steps.
Today the surviving XV-15 can be viewed at the National Air and Space Museum in Washington. The Ospreys it inspired, having weathering monumental teething troubles, are now performing well and are participating in U.S. air operations against the Islamic State.
