Junkers Ju 87 but the Ju 87 continued to be used as a night nuisance-raider until the end of the war. The second prototype had a redesigned single vertical stabiliser and a Junkers Jumo 210 A engine installed, and later the Jumo 210Da. The first A series variant, the A-0, was of all-metal construction, with an enclosed cockpit under a "greenhouse" well-framed canopy; bearing twin radio masts on its aft sections, diagonally mounted to either side of the airframe's planform centreline and unique to the -A version. To ease the difficulty of mass production, the leading edge of the wing was straightened out
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