With development of the P-35 in hand, Seversky Aviation proposed a further development of the basic design with a revised wing and a 1200-hp R-1830-19 air cooled radial engine with a medium-altitude two-stage turbosupercharger in place of the standard 850 hp R-1830-9 engine. The supercharger was located in a ventral position just aft of the wings and had its air intake in the left wing root. Overall length was increased from 25 feet 2 inches to 27 feet 0 inches. In addition, this aircraft had a fully retractable undercarriage, the legs and wheels folding inward into the wings and fuselage. The canopy was somewhat lower than that of the standard P-35, and was more aerodynamically streamlined.
On January 25, 1939, with war clouds gathering in Europe, the USAAC invited manufacturers to submit proposals for new pursuit aircraft. Although the XP-41 showed significantly better performance than that of the standard P-35, the Army preferred the other Seversky developments which was eventually to emerge as the P-43, and the XP-41 was not developed any further. However, some of the development work that went into the XP-41 was used in the design of the P-35A that saw emergency procurement in the 1940/41 era.
Specifications of the XP-41
A maximum speed of 323 mph at 15,000 feet was attained. Maximum range was 1860 miles. Empty weight was 5390 pounds and maximum loaded weight was 7200 pounds. Armament was one 0.50-in and one 0.30-in machine gun.