In 1944, Junkers helped Dornier with work on the Do 335 Zwilling or Dornier Do 635. A meeting was arranged between Junkers and Heinkel engineers, and after the meeting, they began work on the project, named 1075 01-21. The designer, Professor Heinrich Hertel, planned a test flight in late 1945. At the end of 1944, the Germans reviewed aircraft designs with the Japanese military. Among other projects, the Do 635 impressed the Japanese military with its capabilities and design. This design consisted of two Do 335 fuselages, joined by a common centre wing section, with two Rb 50 cameras in the port fuselage for aerial photography. Armament was confined to provision for five 60 kg (130 lb) photo-flash bombs. The mainwheels were common with Ju 352 wheels. It was also intended that two monopropellant Walter Starthilfe RATOG units would be fitted. In early 1945, a wind-tunnel model was tested, and a cockpit mockup was constructed, but the project was cancelled in February 1945, due to the desperate war situation.
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