FSX/P3D v3,v4 Spitfire MK 1A. The first production Spitfire, the mark I was powered by a Merlin III giving 1,030 hp and a maximum speed of 367 mph. This is the mark that mostly fought in the Battle of Britain. It entered service in 1938 with 19 and 66 Squadrons. In all some 1,566 Mk I Spitfires were produced. FSX/P3D model by A.F. Scrub.