North American's Frank Compton started preliminary design work on the FJ-4 in February 1953, four months prior to the first fight of the prototype FJ-3. Experience with early FJ-2's showed the need to dramatically increase the nimble fighter's endurance, while good flying qualities suggested the design would be suitable for a stable fighter-bomber. It was also evident that the inherent stretch needed to develop the Fury/Sabre series into a contender in the supersonic fighter arena did not exist. To this end, Frank Compton's team developed an entirely new aircraft based on the sound design principles used in the FJ-2/3. The result was the FJ-4/4B series, which retained the family resemblance and flying qualities and added the range needed to be successful as an interim attach aircraft, a metamorphosis much like that of the A-7 attack aircraft being developed from the sound engineering found on the F-8 Crusader.