The Junkers Ju 90 was a 40-seat, four-engine airliner developed for and used by Deutsche Luft Hansa shortly before World War II. It was based on the rejected Ju 89 bomber. During the war, the Luftwaffe pressed them into service as military transports. The Junkers Ju 90 airliner and transport series descended directly from the Junkers Ju 89, a contender in the Ural bomber programme aimed at producing a long-range strategic bomber. This concept was abandoned by the Reichsluftfahrtministerium (RLM, Reich Aviation Ministry) in April 1937 in favour of smaller, faster bombers. Design was headed by Ernst Zindel.[1] Development was headed by Professor Herbert Wagner. The Junkers Ju 90 was a four-engine all-metal, low-wing aircraft fitted with twin end-plate vertical stabilizers. The wings were built around five tubular girder spars covered with a smooth stressed skin. The leading edge was quite markedly swept, the trailing edge almost straight. The Junkers "double wing", a full-span movable flap/aileron combination, was fitted. The tail units on the prototypes used the traditional Junkers corrugated skin, the only part of the aircraft to do so, abandoning the exposed corrugated skinning on later Ju 90 production models for the Luftwaffe. The fins and rudders, the latter with prominent horn balances assemblies, were placed at the end of the tailplane; this latter carried the elevators separated by a gap, forming another double wing. These components were as used in the Ju 89. The new fuselage was of oval cross-section, covered by stressed smooth duralumin skin. On the first four Ju 90As, five pairs of rectangular windows were on each side, each double pair lighting a divided-off section of the cabin containing eight seats in facing pairs on either side of a central aisle. The Ju 90B, whose prototypes were the Ju 90 V5 through the Ju 90 V10 aircraft, adopted round fuselage portholes. The Ju 90 V11 became the definitive Ju 290 prototype with smaller, rectangular fuselage windows. The Ju 90B series were visually distinctive because of their oval tail fins. The Ju 90 V6 was withdrawn from test flights, and rebuilt as the Ju 390 V1 prototype. The Ju 90 V9 was also withdrawn and rebuilt as the Ju 390V2, later redesignated in October 1944 as the Ju 390A-1. The Ju 90 V10's rebuild into the Ju 390 V3 bomber prototype was commenced, but was scrapped at the factory in June 1944. The Junkers firm was paid compensation for seven Ju 390s under construction, when Ju 390 orders were cancelled. For more details of design and development, military and civil, click here.
