The Supermarine Spitfire was Britain's most successful fighter of the second World War. The creation of designer, Reginald J. Mitchell, it's original development started in 1925, which resulted in the famous Schneider Trophy contest racers. Eventually, it was developed into a fighter that sustained British hopes during the darkest hours of the Battle of Britain. First flown in 1936, it entered the war just in time for Dunkirk where it established its reputation as a superior fighter and counterbalance to the Messerschmitt Bf 109. The highly maneuverable MK II was an improvement over earlier MK Is. The Merlin V-12 engine was rated at over 1,300 hp, and had a top speed that approached 400 mph.