The McDonnell F3H Demon is a subsonic swept-wing United States Navy carrier-based jet fighter aircraft. The successor to the F2H Banshee, the Demon was originally designed to use the Westinghouse J40 engine, but had to be redesigned to accept the Allison J71 after the J40 suffered severe problems and was ultimately abandoned. Though it lacked sufficient power for supersonic performance, it complemented day fighters such as the Vought F8U Crusader and Grumman F11F Tiger as an all-weather, missile-armed interceptor until 1964. It was withdrawn before it could serve in Vietnam when both it and the Crusader were replaced on Forrestal-class and similar supercarriers by the McDonnell Douglas F-4 Phantom II. McDonnell's Phantom, which was equally capable against ground, fighter, and bomber targets, bears a strong family resemblance, as it was conceived as an advanced development of the Demon. The supersonic United States Air Force F-101 Voodoo was similar in layout, but was derived from the earlier XF-88 Voodoo, which also influenced the Demon's layout. Development work began in 1949, using a swept wing from the start rather than adapting a straight-winged design as was done with the Grumman F9F Panther. A competing contract was also awarded for the delta wing Douglas F4D Skyray. The Skyray, with a top speed of 722 mph (1,162 km/h), would become the Navy's first fighter to fly supersonic in level flight, while the Demon would never reach that level of performance. The original design work was based at its predecessor, the F2H Banshee. However, departing from its tradition of using two engines, the Demon would result in McDonnell's only single-engined carrier-based fighter, adopting under some Navy pressure, the Westinghouse J40 engine. That engine was being promoted by the Navy for its next generation of aircraft, and was to have thrust of over 11,000 lbf (49 kN)—three times that of the engines in the F2H Banshee. It was the first swept-wing design produced by McDonnell and among the first U.S. aircraft to have missile armament. The Navy desperately needed a high performance fighter to meet the challenge of the swept-wing MiG-15 encountered over Korea. Production of the F3H-1N was hastily ordered even before the first flight of the XF3H-1 prototype on 7 August 1951 by test pilot Robert Edholm. The first test flights of the operational design did not occur until January 1953, by which time the Korean War was winding down. The F3H Demon was originally designed around Navy's ambitious new Westinghouse J40 which was to offer enough power to use just one engine in a number of new aircraft designs. But the engine would ultimately fail to produce the promised thrust or run reliably. The engine was a major disappointment, producing only half of the expected power. Worse, it was temperamental and unreliable. Of 35 F3H-1N aircraft flown with the J40 engine, eight were involved in major accidents. The first production Demons were grounded after the loss of six aircraft and four pilots. Time magazine called the Navy's grounding of all Westinghouse-powered F3H-1 Demons a "fiasco", with 21 unflyable planes that could be used only for Navy ground training at a loss of $200 million. One high point of the J40 was the 1955 setting of an unofficial time-to-climb record, in a Demon, of 10,000 feet (3,000 m) in 71 seconds. The proposed F3H-1P reconnaissance version was never built. The J40 program was terminated sometime in 1955. For more information on the development and eight variants, click here.
