This bizarre experimental design was intended to lead to a VTOL ship-based convoy escort fighter but not surprisingly proved difficult to fly. Powered by a very unreliable Allison YT40-A-6 turboprop consisting of two T38s coupled together, it made a first untethered flight and transition to the horizontal in 8.54 - the first successful VTOL flight in history in an aircraft that was not a helicopter or an autogiro. Three were built but this was the only one to fly. Now stored for the NASM