The Whirlwind was a single-seat twin-engine fighter-bomber aircraft introduced in 1940. Only 114 Whirlwinds were built, 2 prototypes and 114 production Mk.I's. At least At least 67 Mk.II conversions were made from the original Mk.I. The Mk.II was fitted with under wing bomb racks and was nicknamed "Whirlibomber". During the Second World War, only three RAF squadrons were equipped with the aircraft and, despite its success as a fighter and ground attack aircraft, it was withdrawn from service in 1943.