Staaken E.4/20 Monoplane

The E.4/20 was the first large all-metal aircraft and the true forerunner of the modern airliner. This ambitious aeroplane was masterminded by 30-year-old German engineer Dr Adolf Rohrbach, chief designer at the Zeppelin company’s plant at Staaken, near Berlin. A four-engine passenger aircraft, it was initially intended for a commercial service between Friedrichshafen, Zeppelin’s main site in southern Germany and Berlin.
Astonishingly advanced, the E.4/20 embodied structural techniques way ahead of its time. Its airframe was built entirely from duralumin profiles, riveted together and covered with a thin duralumin skin. The
similarly skinned high cantilever wing was based on a riveted box spar, to which the leading- and trailing-edge sections and the supports for its Maybach engines were attached. Passengers entered the aircraft through a door in the nose.The rear fuselage
contained a mail compartment, toilet, a separate washroom, and luggage space.
Completed on 30 September 1920, the E.4/20 made several extremely promising flights.
Sadly, however, t his innovative aircraft fell foul of the Inter-Allied Control Commission, which was supervising the demilitarization of Germany under the terms of t he Treaty of Versailles. The Commission ruled that the E.4/20 had the potential to be used as a
warplane. In consequence, the world’s first truly modern transport aircraft was consigned to the scrapheap on 21 November 1922.