Junkers Ju 87 late 1934. It was to have been completed in April 1935, but, due to the inadequate strength of the airframe, construction took until October 1935. The mostly complete Ju 87 V1 W.Nr. 4921 (less non-essential parts) took off for its maiden flight on 17 September 1935. The aircraft was later given the registration D-UBYR. The flight report, by "Hauptmann" Willy Neuenhofen, stated the only problem was with the small radiator, which caused the engine to overheat. The Ju 87 V1, powered by a Rolls-Royce Kestrel V12 cylinder liquid-cooled engine, and with a twin tail, crashed on 24 January 1936 at
Junkers J 2 spin on 23 September 1916 in one of the J 2s, and this event, combined with the substandard climbing performance of the J 2 series of test aircraft, caused "IdFlieg" to withdraw any further governmental support (effectively ending the J 2's contract) for the Junkers firm's advanced monoplane designs until a lighter metal, such as duralumin, was selected for such designs. The first attempt to use duralumin for airframe construction by the Junkers firm was the never-completed J 3 mid-wing, rotary engine-powered, aluminum tubing fuselage single-seat monoplane design, of which only the corrugated sheet duralumin-covered wing structures and "bare" tubular