Staff Writer (Updated: 10/2/2015):
First came the FH "Phantom" of 1947 and 62 examples were completed of this subsonic, straight-winged, twin turbojet-powered development. The Phantom was then followed into service by another jet-powered straight-winged type in the twin-engined F2H "Banshee". This development found greater numerical success in that 895 of the line were produced for the United States and Canada became its only foreign operator. From this work arrived an all-new development, the first by McDonnell to feature swept-back wing mainplanes, in the subsonic F3H "Demon". The Demon was adopted by the USN as a counter to the high-speed, swept-wing Mikoyan-Gurevich MiG-15 "Fagot" jet fighter introduced by the Soviet Union and developed concurrently with the Douglas F4D "Skyray", the USN's first supersonic fighter.
The Demon had roots in a 1949 initiative that sought to produce a swept-wing fighter from the outset as opposed to modifying an existing straight-winged form later on in development. A single engine configuration was selected this time around while the aircraft was to be crewed by one. The engine of choice became the in-development Westinghouse J40 which promised over 10,000 pounds of thrust output from a single source. The power of this one engine alone was seen as sufficient by USN authorities when compared to weaker twin-powered types seen previously and was to mark a new shift in USN aircraft propulsion.
"XF3H-1" was the designation allotted to the two prototypes ordered and these ultimately came equipped with the Westinghouse XJ40-WE-6 turbojet engine though it offered only 6,500 lb of dry thrust and 9,200 lb with afterburner - far below the promised operating figures. The engine never truly shined and made the Demon underpowered while showing itself to be largely unreliable - it had its own development terminated in 1955.
Nevertheless, the USN was in need of high-performance, frontline fighters and continued to push the F3H program along. This resulted in the initial "F3H-1N" production model which continued with the Westinghouse J40-WE-22 engine of 7,200 lb thrust (10,900 lb with afterburner). Fifty-eight of this mark were produced but only 35 carried the J40. At least four airmen lost their lives to these early machines. With the end of the J40 engine project and the subsequent grounding of the active F3H-1N fleet, the proposed "F3H-1P" photo-reconnaissance variant was not followed up on.