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An ornithopter (from Greek ''ornithos'' "bird" and ''pteron'' "wing") is an aircraft that flies by flapping its wings. Designers seek to imitate the flapping-wing flight of birds, bats, and insects. Though machines may differ in form, they are usually built on the same scale as these flying creatures. Manned ornithopters have also been built, and some have been successful. The machines are of two general types: those with engines, and those powered by the muscles of the pilot. == Early history of the ornithopter == Some early manned flight attempts may have been intended to achieve flapping-wing flight though probably only a glide was actually achieved. These include the flights of the 11th-century monk Eilmer of Malmesbury (recorded in the 12th century) and the 9th-century poet Abbas Ibn Firnas (recorded in the 17th century).〔White, Lynn. "Eilmer of Malmesbury, an Eleventh Century Aviator: A Case Study of Technological Innovation, Its Context and Tradition." ''Technology and Culture'', Volume 2, Issue 2, 1961, pp. 97–111 (97–99 resp. 100–101).〕 Roger Bacon, writing in 1260, was also among the first to consider a technological means of flight. In 1485, Leonardo da Vinci began to study the flight of birds. He grasped that humans are too heavy, and not strong enough, to fly using wings simply attached to the arms. He therefore sketched a device in which the aviator lies down on a plank and works two large, membranous wings using hand levers, foot pedals, and a system of pulleys. In 1841, an ironsmith ''kalfa'' (journeyman) Manojlo who "came to Belgrade from Vojvodina"〔(Serbian Icarus, the Kalfa Manojlo (in Serbian) )〕 attempted flying with a device described as an ornithopter ("flapping wings like those of a bird"). Refused by the authorities a permit to take off from the belfry of Belgrade Serbian Orthodox Cathedral, he clandestinely climbed to the rooftop of the Đumrukhana (Import Tax Headoffice) and took off, landing in a heap of snow, and surviving.〔(100 Years of Aviation in Serbia (in Serbian) )〕 The first ornithopters capable of flight were constructed in France. Jobert in 1871 used a rubber band to power a small model bird. Alphonse Pénaud, Abel Hureau de Villeneuve, and Victor Tatin, also made rubber-powered ornithopters during the 1870s.〔Chanute, Octave. 1894, reprinted 1998. Progress in Flying Machines. Dover ISBN 0-486-29981-3〕 Tatin's ornithopter was perhaps the first to use active torsion of the wings, and apparently it served as the basis for a commercial toy offered by Pichancourt c. 1889. Gustave Trouvé was the first to use internal combustion and his 1890 model flew a distance of 80 metres in a demonstration for the French Academy of Sciences. The wings were flapped by gunpowder charges activating a bourdon tube. From 1884 on, Lawrence Hargrave built scores of ornithopters powered by rubber bands, springs, steam, or compressed air.〔W. Hudson Shaw and Olaf Ruhen. 1977. ''Lawrence Hargrave: Explorer, Inventor & Aviation Experimenter''. Cassell Australia Ltd. pp. 53–160.〕 He introduced the use of small flapping wings providing the thrust for a larger fixed wing; this innovation eliminated the need for gear reduction, thereby simplifying the construction. E.P. Frost made ornithopters starting in the 1870s; first models powered by steam engines, then in the 1900s an internal-combustion craft large enough for a person though it did not fly.〔Kelly, Maurice. 2006. ''Steam in the Air''. Ben & Sword Books. Pages 49–55 are about Frost.〕 In the 1930s, Alexander Lippisch and the NSFK in Germany constructed and successfully flew a series of internal-combustion-powered ornithopters, using Hargrave's concept of small flapping wings, but with aerodynamic improvements resulting from methodical study. Erich von Holst also working in the 1930s, achieved great efficiency and realism in his work with ornithopters powered by rubber bands. He achieved perhaps the first success of an ornithopter with a bending wing, intended to imitate more closely the folding wing action of birds although it was not a true variable-span wing like those of birds.〔(Rubber Band Powered Ornithopters ) at Ornithopter Zone web site〕 Around 1960, Percival Spencer successfully flew a series of unmanned ornithopters using internal combustion engines ranging from displacement, and having wingspans up to .〔The complete book of model aircraft, spacecraft, and rockets − by Louis H. Hertz, Bonanza Books, 1968.〕 In 1961, Percival Spencer and Jack Stephenson flew the first successful engine-powered, remotely piloted ornithopter, known as the Spencer Orniplane.〔Video provided by Jack Stephenson: http://www.youtube.com/watch?v=vS4Yz-VcNes〕 The Orniplane had a wingspan, weighed , and was powered by a -displacement 2-stroke engine. It had a biplane configuration, to reduce oscillation of the fuselage.〔RC History Brought Back to Life: Spencer's Ornithopter, by Faye Stilley, Feb 1999 Model Airplane News〕 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「ornithopter」の詳細全文を読む スポンサード リンク
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