The McDonnell F3H Demon was a subsonic swept-wing United States Navy carrier-based jet fighter aircraft. After severe problems with Westinghouse J40 engine that was ultimately abandoned, the successor to the F2H Banshee served starting in 1956 redesigned with the J71 engine.[1] Though it lacked sufficient power for supersonic performance, it complemented daylight dogfighters such as the F8U Crusader and F11F Tiger as an all-weather, missile-armed interceptor[2] until 1964. It was withdrawn before it could serve in the Vietnam when it, and ultimately also the Crusader, was replaced by the extremely successful F4 Phantom.