Dornier Do 217 M-1 medium twin-engine bomber
The creation of the next version of the Do 217 bomber was caused by a shortage of BMW 801 air-cooled engines. These engines were urgently needed for Fw 190A fighters and Ju 88G heavy night fighters.
In order to avoid interruptions in the production of Do 217K bombers, the Dornier Flugzeugwerke designers quickly redesigned the Do 217 K-1 to enable the installation of DB 603 liquid-cooled engines. The DB 603A twelve-cylinder, in-line, liquid-cooled engine had a takeoff power of 1,750 hp and was equipped with a 3.72 m diameter four-bladed propeller.
Due to the new engine's higher fuel consumption, the Do 217M's flight range was reduced by about 150 km. Nevertheless, other flight characteristics of the new variant proved to be better than those of the Do 217K; for example, the plane's maximum flight speed was increased. However, even without its combat load, the aircraft could fly with one working engine only if it was descending.
The Do 217M's armament and bomb capacity were the same as the Do 217K's, but a large-calibre 13 mm Rheinmetall-Borsig MG 131 machine gun was installed in the nose-mounted turret instead of a twin 7,92 mm Mauser MG 81Z machine gun.
Some of the production machines were equipped with FuG 216 Neptun signals intelligence systems that operated in the rear hemisphere and were used to detect radar emissions from British night fighters. The FuG 216 device's antennas were mounted on the wing surfaces.
Aircraft with DB 603A and BMW 801D engines were produced simultaneously from 1942-43. The Do 217 M-1's production was discontinued in September 1943. A total of 443 Do 217 M-1 bombers were built. In 1944, 37 machines of the M-1 variant were converted to Do 217 M-11 guided weapon carriers.
In February 1944, the British managed to get one Do 217 M-1 with minimum damage. On the night of February 23, a bomber from the KG 2 squadron had been damaged by anti-aircraft gun fire over London. The crew immediately abandoned the machine, but the aircraft flew safely about 100 more kilometres and, by itself, landed on its belly near Cambridge.