By 1953, the research team had produced the Firebird XP-21, later referred to as the Firebird I, which was essentially a jet airplane on wheels. It was the first gas turbine powered car tested in the United States. The design is entirely impractical, with a bubble topped canopy over a single seat cockpit, a bullet shaped fuselage made entirely of fiberglass, short wings, and a vertical tail fin. It has a 370 hp Whirlfire Turbo Power gas turbine engine, which has two speeds, and expels jet exhaust at some 1,250 ?F. The entire weight of the car is 2,500 lb.