The Westland Whirlwind was the first cannon-armed fighter for the RAF, first flown in October 1938 and at the production stage by 1940. It was a twin engined heavy fighter (also able to function as a fighter bomber with bombload). With four 20mm Hispano cannon in the nose, it was more powerful than an eight-gunned fighter like the Spitfire or Hurricane. It was fast, matching the current Spitfire's maximum speed but performed best at low altitude and was used for convoy escort and against small targets in the channel and northern France. Only 114 were produced (compared with over 20,000 Spitfires).