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Gliding is a recreational activity and competitive air sport〔 〕 in which pilots fly unpowered aircraft known as gliders or sailplanes using naturally occurring currents of rising air in the atmosphere to remain airborne. The word ''soaring'' is also used for the sport.〔 〕 Gliding as a sport began in the 1920s. Initially the objective was to increase the duration of flights but soon pilots attempted cross-country flights away from the place of launch. Improvements in aerodynamics and in the understanding of weather phenomena have allowed greater distances at higher average speeds. Long distances are now flown using any of the main sources of rising air: ridge lift, thermals and lee waves. When conditions are favorable, experienced pilots can now fly hundreds of kilometres before returning to their home airfields; occasionally flights of more than are achieved.〔 (【引用サイトリンク】 publisher = Fédération Aéronautique Internationale Aeronautique ) 〕 Some competitive pilots fly in races around pre-defined courses. These gliding competitions test pilots' abilities to make best use of local weather conditions as well as their flying skills. Local and national competitions are organized in many countries, and there are biennial World Gliding Championships.〔 (【引用サイトリンク】 publisher = Soaring Society of America )〕〔 〕 Techniques to maximize a glider's speed around the day's task in a competition have been developed, including the optimum speed to fly, navigation using GPS and the carrying of water ballast. If the weather deteriorates pilots are sometimes unable to complete a cross-country flight. Consequently, they may need to land elsewhere, perhaps in a field, but motorglider pilots can avoid this by starting an engine. Powered-aircraft and winches are the two most common means of launching gliders. These and other launch methods require assistance and facilities such as airfields, tugs, and winches. These are usually provided by gliding clubs who also train new pilots and maintain high safety standards. Although in most countries the standards of safety of the pilots and the aircraft are the responsibility of governmental bodies, the clubs and sometimes national gliding associations often have delegated authority. ==History== The development of heavier-than-air flight in the half century between Sir George Cayley's coachman in 1853 and the Wright brothers mainly involved gliders (see Aviation history). However, the sport of gliding only emerged after the First World War, as a result of the Treaty of Versailles,〔 〕 which imposed severe restrictions on the manufacture and use of single-seat powered aircraft in Germany's Weimar Republic. Thus, in the 1920s and 1930s, while aviators and aircraft makers in the rest of the world were working to improve the performance of powered aircraft, the Germans were designing, developing and flying ever more efficient gliders and discovering ways of using the natural forces in the atmosphere to make them fly farther and faster. With the active support of the German government, there were 50,000 glider pilots by 1937.〔 〕 The first German gliding competition was held at the Wasserkuppe in 1920,〔 (【引用サイトリンク】 publisher = International Scale Soaring Association )〕〔 〕 organized by Oskar Ursinus. The best flight lasted two minutes and set a world distance record of .〔 Within ten years, it had become an international event in which the achieved durations and distances had increased greatly. In 1931, Gunther Grönhoff flew on the front of a storm from Munich to Kadaň (Kaaden in German) in Western Czechoslovakia, farther than had been thought possible.〔 In the 1930s, gliding spread to many other countries. In the 1936 Summer Olympics in Berlin gliding was a demonstration sport, and it was scheduled to be a full Olympic sport in the 1940 Games.〔 A glider, the Olympia, was developed in Germany for the event, but World War II intervened. By 1939 the major gliding records were held by Russians, including a distance record of .〔 During the war, the sport of gliding in Europe was largely suspended, though several German fighter aces in the conflict, including Erich Hartmann, began their flight training in gliders.〔 〕 Gliding did not return to the Olympics after the war for two reasons: a shortage of gliders, and the failure to agree on a single model of competition glider. (Some in the community feared doing so would hinder development of new designs.)〔 The re-introduction of air sports such as gliding to the Olympics has occasionally been proposed by the world governing body, the Fédération Aéronautique Internationale (FAI), but has been rejected on the grounds of lack of public interest.〔 〕 In many countries during the 1950s a large number of trained pilots wanted to continue flying. Many were also aeronautical engineers who could design, build and maintain gliders. They started both clubs and manufacturers, many of which still exist. This stimulated the development of both gliding and gliders, for example the membership of the Soaring Society of America increased from 1,000 to 16,000 by 1980.〔 〕 The increased numbers of pilots, greater knowledge and improving technology helped set new records, for example the pre-war altitude record was doubled by 1950,〔 and the first flight was achieved in 1964.〔(【引用サイトリンク】 publisher = Fédération Aéronautique Internationale Aeronautique )〕 New materials such as glass fiber and carbon fiber, advances in wing shapes and airfoils, electronic instruments, the Global Positioning System and improved weather forecasting have since allowed many pilots to make flights that were once extraordinary. Today over 550 pilots have made flights over .〔 (【引用サイトリンク】 publisher = Fédération Aéronautique Internationale Aeronautique )〕 Although there is no Olympic competition, there are the World Gliding Championships. The first event was held at the Samedan in 1948.〔 Since World War II it has been held every two years. There are now six classes open to both sexes, plus three classes for women and two junior classes. The latest worldwide statistics for 2011 indicate that Germany, the sport's birthplace, is still a center of the gliding world: it accounted for 27 percent of the world's glider pilots,〔 〕 and the three major glider manufacturers are still based there. However the meteorological conditions that allow soaring are common and the sport has been taken up in many countries. At the last count there were over 111,000 active civilian glider pilots and 32,920 gliders,〔 plus an unknown number of military cadets and aircraft. Clubs actively seek new members by giving trial flights, which are also a useful source of revenue for them.〔(【引用サイトリンク】 publisher = British Gliding Association )〕 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「Gliding」の詳細全文を読む スポンサード リンク
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