A contractual modification enabled Seversky to complete the airframe to a standard similar to that of the private-venture AP-4. The AP-9 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.
Span: 36 ft 0 in (10.97 m)
Length: 27 ft 0 in (8.23 m)
Height: 12 ft 6 in (3.81 m)
Wing area: 220 sq.ft (20.44 sq.m)
Weight empty: 5,390 lb (2,445 kg)
Loaded weight: 6,600 lb (2,994 kg)
Max speed: 323 mph (520 kmh) at 15,000 ft (4,572 m)
Range: 730 mls (1,175 km)