The XP-36F was created by taking P-36A Ser No 38-172 and fitting it with two 23-mm Danish-built Madsen cannon in underwing fairings. The standard P-36A fuselage armament was retained. Unfortunately, this additional armament caused the maximum weight to rise to 6850 pounds and the maximum speed to fall to 265 mph. Consequently, the experimental armament was soon removed and the airplane reverted to a standard P-36A. It was surveyed in October 1944.