The last gasp of the Airacomet design was the XP-83, first flown in February 1945. A principal problem with the early jets was their lack of endurance, a fault attributable to the great thirst of the early turbojets. Bell attempted to remedy this in the XP-83 by designing what amounted to a much-scaled up Airacomet, with sufficient internal room to carry over a thousand gallons of fuel. This came at a toll, as although the -83's J35 engines were much more powerful than the Airacomet's J31s, the XP-83 was heavier empty than the P-59B was loaded. Performance inevitably suffered, and only two XP-83s were built.
The initial prototype was lost in September 1946; the aircraft had been refitted to test ramjet engines underwing, and on this occasion one of the engines caught fire, forcing the pilot and test engineer to bail out. The second aircraft had a larger tail to counter stability problems, but after a short life this example was scrapped.
Armament options for production aircraft would have been 6x.50-cal M2s, an equal number of .60-cal T17E3s, a quartet of 20mm Hispanos, or a single 30mm cannon.