No. 9620. Curtiss H75I YP-37 US Army Air Corps
Aeroplane Photo Supply (APS) Photo No. 359

Curtiss H75I YP-37

01/31/2010. Remarks by Johan Visschedijk: "In the mid '30s, the USAAC held to its belief that liquid-cooled engines offered definite advantages over air-cooled engines for fighter aircraft. Having funded development of the twelve-cylinder liquid-cooled Allison V-1710, the service placed an order with Curtiss on February 16 1937 for an adaptation of the P-36 airframe with a V-1710-C7 engine as the XP-37.

Although the basic airframe of the P-36 was retained, the cockpit was moved aft for CofG reasons and the aircraft was powered by a V-1710-11 (C8) engine with a General Electric turbo-supercharger and affording 1,150 hp for take-off and 1,000 hp at 20,000 ft (6,100 m). Armament remained one 0.5 in (12.7 mm) and one 0.3 in (7.62 mm) gun. Flown on April 20, 1937, the XP-37 succeeded in achieving 340 mph (547 kmh) at 20,000 ft (6,096 m), but suffered frequent turbo-supercharger malfunction.

An order for 13 service test examples was placed on December 11, 1937. Powered by the V-1710-21 with an improved supercharger and rated at 1,000 hp for take-off and 880 hp at 25,000 ft (7620 m), the service test model was designated YP-37. It featured a 1 ft 10 in (0.56 m) longer fuselage and 451 lb (204.5 kg) and 539 lb (244 kg) increases in empty and normal gross weights respectively.

Delivered to the USAAC between April 29, 1939 and December 5, 1939, the YP-37s were dogged by mechanical problems, and further development was discontinued in favor of the P-40.

Created January 31, 2010