The Focke-Wulf Fw 190 was a German single-seat, single-radial engine fighter aircraft designed by Kurt Tank in the late 1930s. It was used by the Luftwaffe during the Second World War in a variety of roles. Like the Bf 109, the Fw 190 was employed as a workhorse, and proved suitable for a wide variety of roles, including air superiority fighter, strike fighter, ground-attack aircraft, escort fighter, and operated with less success as a night fighter. Early 190s performance decreased at high altitudes (usually 6,000 m (20,000 ft) and above) which complicated its use as a high-altitude interceptor, but these complications were mostly rectified in later models, notably the Focke-Wulf Fw 190D variant in the autumn of 1944. In spite of its successes, it never entirely replaced the Messerschmitt Bf 109.