The appearance of the Soviet swept-wing MIG-15 in the air war in Korea hastened the Navy to order the F3H-1N into production in spite of the fact that the XF3H-1 had yet make its first flight. In fact, the Navy went so far as to award a contract to the Dallas, Texas based Temco Aircraft Corp. for 100 Demons under license from McDonnell. This ill-conceived, hasty decision was to have disastrous results.
The F3H-1N airframe varied from that of the prototype by having the ailerons moved inboard to mid-wing and the radome and cockpit where angled downward by five degrees to alleviate the forward visibility problem encountered during carrier landings. Fuel tank size was increased by 378 gallons (2756 lbs). The APG-30 radar and four 20mm cannon were installed as components of the weapon system. The mounting of the 20mm cannon just behind the jet engine air intakes was to cause significant problems later in the program.
The Navy clearly had high hopes for the F3H platform because in September, 1952 the ordered 22 photo-reconnaissance versions of the F3H-1N designated the F3H-1P. The guns and radar were replaced by cameras in this version.
The F3H-1N was initially powered by the Westinghouse J40-WE-8 turbojet engine but the J40-WE-22 was installed in the production aircraft. The Navy knew that the aircraft was grossly under-powered with this engine and planned to replace it with J40-WE-24 when it was ready. But by September of 1953, the Navy realized that Westinghouse was not going to produce the WE-24 and that they were stuck with the WE-22.
The first production model of the F3H-1N, BuNo. 133489, made it's first flight Christmas eve of 1953. That aircraft went to NATC Patuxent River, Maryland early the next year for service evaluation flights.
Late delivery of J40-WE-22 engines drastically slowed down the F3H-1N production line. Serious problems also plagued the Navy service test program. Eleven accidents, some fatal, over several days got the attention of the press and they complained loudly about how the Navy was spending a lot of money to acquire an aircraft whose greatest virtue seemed to be in killing its own pilots. This was the truth since the F3H-1N was a dangerous aircraft to fly and one that was hated by its pilots. But in the face of this, the aircraft actually set an unofficial time-to-climb to record by going to 10,000 feet in 71seconds.
Facing the fact that there was no way to solve the J40 engine problems, the Navy halted production of the F3H-1N after the 58th aircraft rolled off the line. TemCo's contract was cancelled and the F3H-1P program was cancelled before a single aircraft was built. In July of 1955 the Navy reluctantly grounded all F3H-1Ns and had to face growing congressional disfavor in light of the 200 million dollars expended on the aircraft and its ill-fated engine. Worse, the Navy had to endure the humiliation of barging F3H-1Ns from St. Louis to Memphis, where the would be towed to the Naval Air Station for maintenance training, and barging F3H-1Ns from Patuxtant River down to Norfolk for the same purpose.
The utter failure of the J40 engine forced Westinghouse to shut down its jet engine manufacturing division. The future of McDonnell looked rather grim at the time but the company was able to survive and go on to bigger and better things by building the F3H-2 version of the Demon which was fitted with the Allison J71 engine.
F3H-1N (BuNo. 133489) take-off from Lambert Field