One of the greatest fighting aeroplanes in the history of aviation, the Messerschmitt Bf 109 was always at the forefront of world fighter design and, just like its adversary the Spitfire, was in constant development throughout the Second World War. Major variants of the fighter usually coincided with developments in the Daimler Benz engine which powered the Messerschmitt. Of the five major variants, the F or ‘Friedrich’ is usually considered the most refined version of the Bf 109. Introduced during the spring of 1941, the Bf 109F was superior to RAF Spitfires in service at that time and was flown by many successful Luftwaffe aces.