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__NOTOC__ The Schweizer SGS 1-21 is a United States single-seat, mid-wing, Open Class glider built by Schweizer Aircraft of Elmira, New York.〔〔Schweizer, Paul A: ''Wings Like Eagles, The Story of Soaring in the United States'', pages 99-111. Smithsonian Institution Press, 1988. ISBN 0-87474-828-3〕 The 1-21 was a clean-sheet design intended to fill the role of high performance competition sailplane. It was designed by Ernest Schweizer and first announced in the September–October 1946 issue of the Soaring Society of America's ''Soaring'' magazine.〔 ==Design and development== Following World War II soaring in the United States was dominated by surplus two-place gliders that had been used as trainers by the military, such as the TG-1, TG-2 and TG-3.〔 By the end of the war there were only about 400 gliders in the US. Of these only about a dozen were high performance competition sailplanes and half of these were pre-war designs. Schweizer Aircraft realized that if the US was to progress in the sport of soaring, that domestic mass-produced, high performance sailplanes would be needed.〔 The 1-21 was designed to be the high performance sailplane of choice in the post war era. While design had been completed in the summer of 1946, Schweizer had not built a prototype, hoping to get sufficient orders to make it worthwhile.〔 Two orders were received as a result of the publicity in ''Soaring''. One was from Dick Comey and the other from David Stacy, both members of the Harvard Glider Club. The company decided that these two orders were sufficient to proceed with production. The 1-21's price was set at USD$2750.〔 The 1-21 was of all-metal construction and incorporated some innovative features, including:〔〔〔 *Water ballast (266 lbs, 121 kg) in two wing tanks *High aspect ratio wing of 15.75 *Two spoilers on the top of each wing and one underneath The 1-21 design was never certified and both aircraft are experimental aircraft in the "racing, exhibition" class.〔 The SGS 1-21 was intended to be produced in much larger numbers than the two examples that were completed. A combination of factors prevented this, despite its initial successes. The aircraft was introduced just as the forecast post-war aviation boom failed to materialize. The 1-21's introductory price of USD$2750 was too high for the market.〔 The Schweizers felt that there was good demand for an aircraft in the performance range of the 1-21, but at a lower cost. As a result the 1-21 was redesigned and simplified. The resulting aircraft was of equal performance and could be sold for USD$2000. This new aircraft was designated the Schweizer SGS 1-23 and went on to become a great success with 93 examples having been produced. The 1-23 remained in production until 1967.〔 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「Schweizer SGS 1-21」の詳細全文を読む スポンサード リンク
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