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
Hugo Junkers in Dessau. The iron wings were patented one year later. Junkers had a wind tunnel built and invented a hydraulic brake. He had far-sighted ideas of metal aeroplanes and flying wings, but the necessities of the war held him back. During World War I, the government forced him to focus on aircraft production. In 1915, he developed the world's first practical all-metal aircraft design, the Junkers J 1 "Blechesel" (Sheetmetal Donkey), which survived on display in Deutsches Museum in Munich until World War II. His firm's first military production design in 1916–17 was the armored-fuselage, two-seat, all-metal sesquiplane known by