Curtiss 75S / XP-42
The Curtiss XP-42, a conversion of a P-36A Mohawk airframe and given the S/N of 38-004, was employed as a testbed at Wright Field, Ohio. Beginning in March 1939 test attempted to determine whether stream-lining could reduce drag in a radial-powered fighter and make it competitive with more advanced fighters employing inline engines.
Delivered to the Army in March 1939, the XP-42 was powered by a 1,050 hp / 783kW Pratt & Whitney R-1830-31 Twin Wasp radial enclosed by a bullet-shaped, sheet-metal cowling extended forward to a large, pointed spinner and a three-blade propeller. A long shaft was developed to drive the propeller but gave serious vibration problems. An airscoop below the spinner provided cooling air, while smaller intakes above the engine provided air to the carburettor.
The aerodynamic nose shape provided almost no reduction in drag, and cooling problems proved almost insurmountable. While the XP-42 was marginally faster than the open-cowl P-36A, its performance did not compare favourably with the P-40 or with other, newer fighters of the immediate pre-war period.
A variety of nose configurations was tried on the XP-42, altering its fuselage length with each change, but none vindicated the enclosed radial engine. When hostilities began, the XP-42 had been ruled out as a possible production aircraft but continued to aid in research. In 1942, the XP-42 tested an all-flying stabilizer, similar to the stabilator found on modern jets. The XP-42 had begun flying in natural metal finish and was camouflaged during one of its minor rebuilds. The airframe, which contributed knowledge to designers and engineers, was eventually taken out of service. The entire project was officially ended by 1947, at which the aircraft was scrapped for parts.
Engine: 1 x Pratt & Whitney R-1830-31 radial engine, 1,050hp.
Length: 28.22ft (8.6m)
Wingspan: 11.38 m / 37 ft 4 in
Wing area: 21.83 sq.m / 234.98 sq ft
Height: 8.20ft (2.50m)
Empty Weight: 4,817lbs (2,185kg)
Maximum Take-Off Weight: 5,648lbs (2,562kg)
Maximum Speed: 250mph (402kmh; 217kts)
Maximum Range: 830miles (1,336km)
Service Ceiling: 37,198ft (11,338m)