The Westland Whirlwind was a British twin-engine heavy fighter. It was the Royal Air Force's first single-seat, twin-engine, cannon-armed fighter, and a contemporary of the Supermarine Spitfire and Hawker Hurricane. It was one of the fastest aircraft in service when it flew in the late 1930s, and was much more heavily armed than any other. However, protracted development problems with its Rolls-Royce Peregrine engines delayed the entire project and only a relatively small number were ever built. During the Second World War only two RAF squadrons were equipped with the Whirlwind, and despite successful use as a fighter-bomber it was withdrawn from service in 1943.