Ni ibẹrẹ 1937, awọn USAAC paṣẹ Curtiss lati mu ọkan P-36 si awọn titun omi-tutu turbo-supercharged Allison V-1710 engine pẹlu 1,150 hp (860 kW). Designated Curtiss XP-37, awọn ofurufu lo awọn atilẹba awoṣe 75 airframe pẹlu radiators ti a fi sori awọn ẹgbẹ ti awọn fuselage ni ayika awọn engine. awọn cockpit ti a gbe jina si ẹhin lati ṣe yara fun awọn radiators ati awọn turky bulbocharger eto, ati lati iwontunwonsi awọn ofurufu. awọn ofurufu fò ni April 1937, de ọdọ 340 mph (550 km / h) ni 20,000 ft (6,100 m). biotilejepe awọn turbo-supercharger wà lalailopinpin unreliable ati wiwo lati awọn cockpit lori takeoff ati ibalẹ je fere nonexistent, awọn USAAC ti a ti ni ileri to intrigued nipa awọn 13 turbo-turbo-fififififi ibere lati se idanwo YP-37 ati awọn ẹya ara ẹrọ? Curtiss fò ni June 1939.
Ọdún 1939