Convair XP-81

Mixed Power Fighter

The first prototype XP-81 44-91000 (note the oil leak on the wing)

Engine: 1x General Electric XT31-GE-1(TG-100) turboprop@ 2,300 hp /1x Allison J33-GE-5 turbojet making 3,750 lb of thrust.

Wing Span: 50' 6''

Length: 44' 10''

Height: 14'

Weight: Empty 12,755 lb / loaded 24,650 lb

Maximum Speed: 507 mph

Range: 2,500 miles

Ceiling: 35,53'

Crew: 1 Pilot

Armament: 6x 0.50''machine guns / 2x 1,600 lb bombs

History:

Designed by Charles.R."Jack" Irvine and Frank.W.Davis of the newly merged Consolidated and Vultee aircraft companies, now known as Convair, to a USAAF requirement for a mixed power escort fighter in 1943. Work began on the Model 102 on the 5/1/1944, with the USAAF ordering two prototypes on the 11/2/1944 under the designation of XP-81, a little later an order for 13 YP-81 pre-production aircraft was issued, requiring some changes in the turboprop engine to the TG-110 and an increase in the armament to 6x 20 mm cannons.

Due to problems with the General Electric TG-100, a Paccar"Merlin"V-1650 piston engine was fitted, with the radiator just below the propeller spinner, for the first flight on the 11/2/1945 of the XP-81(44-91000) Some problems were found with the stability, but this was cured with a 15'' tail fin extension and a ventral fin.

A line drawing of the first XP-81 with it's Merlin piston engine

However the war against Japan was coming to an end and the order for the YP-81s was canceled just before VJ day, but testing continued on the two XP-81 prototypes. After the flight with the piston engine the first aircraft was fitted with it's General Electric TG-100 turboprop engine, with the first flight being on the 21/12/1945. The results were disappointing as the TG-100 only produced 1,400 hp instead of the hoped for 2,300 hp and the engine suffered from persistent oil leaks, plus there was excess propeller vibration none of which were overcome. The XP-81 program was terminated on the 9/5/1947, both aircraft were redesignated to ZXP-81 in 1948 and were sent to the photographic and bombing range at Edwards AFB in 1949.

The second XP-81 prototype 44-91001