Initial Flight Experience With Lift Fan Propulsion

The first ten flight hours of the U.S. Army XV-5A lift fan aircraft have been completed at the General Electric Flight Test Operation, Edwards Air Force Base. Approximately equal flight time has been accummulated in low speed conventional turbojet-powered flight and VTOL fan-powered flight.

Conventional flight between wing stall speed and 160 knots has met design objectives in terms of installed turbojet performance, compatibility of the convertible lift fan propulsion system, power requirements, stability and general handling qualities.

Over thirty vertical lift-offs have demonstrated a thrust augmentation of nearly three with fan-derived control performance achieving desirable levels. Qualitative pilot evaluations indicate XV-5A simpler to fly than most rotorcraft. Next flight test sequence will use both aircraft to simultaneously expand conventional flight envelope and explore transition flight through propulsion system conversion speed.