The Messerschmitt Bf 109 was built from 1935 onwards and, with a production of around 33,000 aircraft, is the most widely produced fighter aircraft in the history of aviation. Officially, the type designation Bf 109 was never changed, even after BFW was renamed Messerschmitt AG. However, since all aircraft types later developed by Messerschmitt were given the model abbreviation ME, the name ME 109 also became established in the public consciousness for the Bf 109. In the 1930s, it marked the step towards a new generation of low-wing fighter aircraft with a closed pilot's cockpit, retractable landing gear and an all-metal construction of wings and fuselage. This new structure withstood far greater loads than the fabric-covered tubular constructions that had been common up to then, which also had the disadvantage of immense air resistance due to the necessary transverse bracing. As a result, the Messerschmitt's more compact and stable design allowed higher speeds with tighter radii during the cornering and dive manoeuvres so crucial to fighter pilots. The Bf 109 was armed with two 20 mm MG FF machine guns in the wings and two 7.92 mm MG 17 machine guns. The latter were mounted directly in front of the pilot and coupled via an interrupter gear to the propeller shaft of the 1,000 hp Daimler V12 engine. In this way it was possible for the MGs to fire through the circular path of the spinning propeller without the projectiles hitting the rotating propeller blades.