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The Daimler L20, later known as the Klemm-Daimler L20, was one of the first light aircraft to be built in significant numbers. A two-seater with an engine of only , it demonstrated the ability of a small aircraft to cope with flights over the Alps in winter and to make transcontinental journeys of over 36,000 km. ==Design and development== thumb Hans Klemm's first light aircraft was the Daimler L15 and the L20 had much in common with it. Both were cantilever monoplanes with twin open, tandem cockpits and engines of very low power. The L20's low wing distinguished it from its predecessor and had the advantage of providing a low centre of gravity and better view during the landing approach as well as better protection for occupants in case of crash landings. The low-set wing also allowed a shorter undercarriage on the L20, which was otherwise like that of the L15 with the wheels independently mounted on pairs of centrally hinged V-struts and with vertical shock absorbing legs to the wing underside.〔 Wheels were sometimes replaced by floats. Intended from the start for serial production, the L20's structure was simplified, with a pentagonal cross-section fuselage lacking the L15's rounded upper and lower surfaces.〔 The fuselage was wooden framed with canvas covering.〔 The overall strength of the structure, which had a safety factor of 12, was emphasised.〔 The wing was tapered in planform and was built around two spars, though there were two variants of the internal wing structure. The first three aircraft, type L20 A1, had wings stiffened against torsion by internal wire bracing but later aircraft, type L20 B1, used a torsion box formed by plywood skin ahead of the rear spar.〔 Like the later version of the L15, the L20 used a combination of conventional ailerons and unusual wingtip flaps, rotating about an axis well ahead of mid-chord. The ailerons were directly controlled from the cockpit as normal and the tip flaps were linked to them with external rods and cranks. On early examples these flaps were roughly square, with a side less than a half of the chord at the tip,〔 but at some later time they were reshaped to produce wing curved tips. The wings could be detached at the root in about five minutes, reducing the width of the L20 to for road transport on a trailer pulled by a car.〔〔 At the beginning of the design and testing period the absence of a suitable, serially produced light aircraft engine was a concern and the wing was therefore mounted so that it could be moved fore and aft to allow for the varying centre of gravity positions resulting from engines of different weight. A glider version was contemplated though not finally used. Instead, the flight programme began with the L20 powered by the Harley-Davidson motor cycle engine used in the L15. By mid 1925 this had been replaced with a new engine, the air-cooled, flat twin Mercedes F7502a, which Klemm had persuaded Daimler's engine group to design and build for the light aircraft market. The cost of flying the L20 was low as its cruise fuel consumption was only 63 mL/km (45 mpg). From 1926 the uprated Mercedes F7502b was fitted. The F7502 was central to the success of the L20, though it suffered from repeated rocker arm failures.〔 Having failed to persuade the Daimler management to undertake series production of the L20 despite its early successes, in 1927 Klemm left to set up his own company, Klemm Light Aircraft in Sindelfingen, later moving to Böblingen.〔〔 Thereafter the L20 was often known as the Klemm-Daimler L20 or sometimes the Daimler-Klemm L20. After 1926, new designs appeared under Klemm's name alone; for example the Klemm L25, later Kl25, was a revision of the L20 with a Salmson radial engine. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Daimler L20」の詳細全文を読む スポンサード リンク
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