Dornier Do P

06/30/2011. Remarks by Johan Visschedijk: "This four-engined six-seat heavy bomber was developed as part of the secret rearmament of the German forces. Due to a requirement of the Fliegergruppe (Aviation Department) in the RWM (Reichswehrministerium, State Defense Ministry), the RVM (Reichsverkehrsministerium, Ministry of Transportation) awarded a development contract to Dornier on March 29, 1929.

Construction of the prototype was started at Manzell, Friedrichshafen in July 1929, and fitted with four 525 hp Siemens Jupiter VI engines, the first flight took place at the factory airfield Friedrichshafen-Löwenthal on March 31, 1930. In the same year it was tested at the Swiss Dornier factory at Altenrhein (some 13 mls, 21 km across Lake Constance), where it subsequently was modified to a bomber. It could carry sixty 110 lb (50 kg) bombs internally, or four 551 lb (250 kg) bombs externally and twenty 55 lb (25 kg) bombs internally. For testing it was registered in Switzerland on November 24, 1930, as CH-302 to Aero Metall AG in Zürich, another Dornier company.

After completion of the testing the military equipment was removed at Altenrhein, to improve longitudinal stability an additional stabilizer was fitted between the two fins. The aircraft returned to Germany, first to Friedrichshafen-Löwenthal and finally to the DVL at Berlin-Staaken. Already on March 20, 1931, the DVL had taken over the aircraft for the RDL, by then registered under the German registration D-1982, as a night freight aircraft.

At that time the RDL operated not only the disguised military installations at Staaken, but also Rechlin, Travemünde, Johannesthal and especially in Lipetsk, Russia, where in 1932 the Do P was put through technical and tactical tests. Among other things, it tested the newly developed MG 15 machine gun (fitted on the new D 30 turntable mount) of which three were provided, one each in the nose, dorsal and ventral position. When Lipetsk was dissolved in October 1933, the aircraft was left behind as it had been judged as "of no strategic value", it served with the Soviets as a trainer until it crashed in 1935."