X-Plane 9.70+ Spitfire Mark XIV 1.0. The Supermarine Spitfire Mk XIV was the one of the first Griffon-engined Spitfires and was introduced to serve as a first line fighter in early 1944. It could climb to 20,000 ft (6100 m) in just over five minutes and its top speed, which was achieved at 25,400 ft (7700 m), was 446 mph. In operational service many pilots initially found that the new fighter could be difficult to handle, particularly if they were used to earlier Spitfire marks. By Thibaud Duhamel.