When, in 1936, the USAAC Materiel Division placed an order for the SEV-1XP as the P-35, it had stipulated that the 77th and last series aircraft be fitted with a more powerful supercharged engine. The chosen engine was the Pratt & Whitney R-1830-19 of 1,200hp, fitted with an integral medium-altitude two-stage mechanical supercharger. A contractual modification enabled Seversky to complete the airframe to a standard similar to that of the private-venture AP-4. The AP-9 (see Republic) was, in fact, used for competitive evaluation at Dayton in lieu of the XP-41 until the latter became available. Power plant apart, the aircraft was in virtually all respects similar to the AP-4. The XP-41 was delivered to Wright Field for USAAC evaluation in February 1939, but the Air Corps preferred the turbo-supercharged AP-4 and further development of the XP-41 was discontinued, although trials continued at Langley. This was the last of the Kartveli-designed fighters to bear the Seversky appellation, as the company thereafter became the Republic Aviation Corporation.
Max take-off weight: 3175 kg / 7000 lb Empty weight: 2445 kg / 5390 lb Wingspan: 10.97 m / 36 ft 0 in Length: 8.23 m / 27 ft 0 in Height: 3.78 m / 12 ft 5 in Wing area: 20.44 sq.m / 220.01 sq ft Max. speed: 520 km/h / 323 mph Ceiling: 7000 m / 22950 ft Range: 789 km / 490 miles Armament: 1 x 7.62mm + 1 x 12.7mm machine-guns