As the Luftwaffe's standard fighter, beginning in 1937 the Bf 109 was produced in large numbers and after the outbreak of the Second World War saw action over every front. With this light, high-performance aircraft Professor Willy Messerschmitt had created a ground-breaking design. The Bf 109 had to remain in continuous development in order to keep pace with advances in Allied fighter design. 1941 saw the advent of the Bf 109 F, a clearly improved version, which was soon replaced by the more powerful and better armed Bf 109 G. The Bf 109 H high-altitude fighter reached a ceiling of 14,000 meters, and the Bf 109 K, the most potent of all the variants of this fighter aircraft, entered production in the last year of the war. This is a complete summary of all versions from the Bf 109 F to K with many photographs, some never before published, and details.

Messerschmitt Bf 109 F (Friedrich) is one of the most important versions of this famous fighter. It was powered by the same engine (DB 601E) as the preceding Bf 109 E (Emil), but the airframe design differed significantly compared to its predecessor. The plane gained a more aerodynamic profile due to the new engine cowling (the engine had its own starter, which resulted in the extension of the unit), a new, rounder propeller hub and rounded wing tips. In addition, supports were removed under horizontal stabilizers. Bf 109 F had its first flight on January 26, 1939. Two prototypes were built. Two machines in version Bf 109 D were also rebuilt for testing the new engine installations. Friedrich had new under-wing radiators, which were twice as wide and lower than those used in the previous version of the aircraft. They were equipped with a two-part flap regulating the air supply. The prolonged tests and new requirements on the fighter's armament delayed the implementation of Bf 109 F for series production. The Messerschmitt company had signed a contract with the Reich Ministry of Aviation, which specified the requirements for two variants of the fighter's weaponry: a light variant with MG151/15 in the fuselage and a heavy variant with MG FF/M in the fuselage.