Messerschmitt Bf 109 109 was steadily being supplemented by the Focke-Wulf Fw 190. It was commonly called the Me 109, most often by Allied aircrew and even among the German aces themselves, even though this was not the official German designation. It was designed by Willy Messerschmitt and Robert Lusser, who worked at Bayerische Flugzeugwerke during the early to mid-1930s. Whilst the 109 was conceived as an interceptor, later models were developed to fulfill multiple tasks, serving as bomber escort, fighter-bomber, day-, night-, all-weather fighter, ground-attack aircraft, and as reconnaissance aircraft. It was supplied to and operated by several states during World War
Messerschmitt Bf 109 variants roles, a reconnaissance or bad-weather fighter, for example. Unlike the "Rüstsatz" field-kits, these modifications were permanent. The "Rüstsatz" kits were labelled with the letter "R" and a Roman numeral. "Rüstsatz" kits did not alter the aircraft type so a Bf 109 G-6 with "Rüstsatz" II (50 kg/110 lb bombs) remained a Bf 109 G-6 and not G-6/R2, which was a reconnaissance fighter with MW 50, as suggested by most publications. The "Umrüst-Bausatz", "Umbau" or "Rüstzustand" were identified with either an "/R" or "/U" suffix and an Arabic number, e.g. Bf 109 G-10/U4. Common "Rüstsatz" kits: Bf 109G: Common "Umrüst-Bausatz" ("Umbau")