Messerschmitt Bf 109 11 July 1938 when Erhard Milch finally allowed Willy Messerschmitt to acquire the company. All Messerschmitt aircraft that originated after that date, such as the Me 210, were to carry the "Me" designation. Despite regulations by the RLM, wartime documents from Messerschmitt AG, RLM and "Luftwaffe" loss and strength reports continued to use both designations, sometimes even on the same page. All extant airframes bear the official "Bf 109" designation on their identification plates, including the final K-4 models. The aircraft was often referred to by the folk-designation, 'Me 109', particularly by the Allies. The aircraft was often nicknamed "Messer"
Messerschmitt Bf 109 variants as all of the 235 Bf 109Ds still in Luftwaffe service at the beginning of the Poland Campaign were rapidly taken out of service and replaced by the Bf 109E, except in some night fighter units where some examples were used into early 1940. Variants included the D-0 and D-1 models, both having a Junkers Jumo 210D engine and armed with two wing-mounted and two nose-mounted 7.92 mm (.312 in) MG 17s.> The D-2 was an experimental version with an engine-mounted machine gun, but as previously tried, this installation failed. The D-3 was similar to the C-3 but with two