Hang gliding is an air sport employing a foot-launchable aircraft. Typically, a modern hang glider is constructed of an aluminium alloy or composite-framed fabric wing. The pilot is ensconced in a harness suspended from the airframe, and exercises control by shifting body weight in opposition to a control frame.
Overview Early hang glider designs did not enable reliable safe flight, their builders lacking a comprehensive understanding of the underlying principles of flight. The first recorded controlled flights were by German engineer Otto Lilienthal, whose research, published in 1889, strongly influenced later designers. That same year, similar designs were also successfully employed in Calabria, Italy by aeronautics inventor and artist, Vincenzo Raschella. The types of aircraft employed by Lilienthal and Raschella are now referred to as hang gliders. Further hang glider research was undertaken during the 1920s in Europe, Australia and the US, where designers tested several wing concepts and the 'pendulum weight-shift control system'. In 1957 the American space agency NASA began testing various formats of a new wing called the Rogallo wing with the intent of possibly implementing the design as a recovery system for the Gemini space capsules. The wing's simplicity of design and ease of construction, in combination with its slow flight characteristics, did not go unnoticed by hang glider enthusiasts; Rogallo's flexible wing airfoil was soon adapted by John Wallace Dickenson in 1963, to the purpose of recreational flight, launching a hang glider renaissance.
Early history George Cayley constructed a slope-launched glider that flew with a pilot in 1853. Starting in the 1880s, advancements were made in aerodynamics and construction that led to the first truly practical gliders; this information was often shared and published by early aviators and inventors, building a long series of incremental achievements. Through the 1880s, several aviation pioneers emerged in different countries around the world, and they all pursued glider designs with varying degrees of success. Chief among these were Otto Lilienthal in Berlin, Germany; Vincenzo Raschella in Calabria, Italy; Lawrence Hargrave in Sydney, Australia; Percy Pilcher in the United Kingdom; John Joseph Montgomery at Otay Mesa near San Diego, California (1880s); as well as at Santa Clara, California (1905) Octave Chanute and his team in Gary, Indiana, in the US, to name but a few. Otto Lilienthal duplicated some of his contemporaries' work and greatly expanded on it from 1874, publishing all of his research in 1889. He also produced a series of gliders, and in 1891 was able to make controlled flights of 25 metres (82 ft) or more routinely, as well as some soaring flights. He rigorously documented his work, influencing later designers; for this reason he is one of the best known and most influential of the early aviation pioneers. His type of aircraft is now known as a hang glider. By 1896, he had made about 2,000 flights of 250 metres (820 ft) with a number of his designs when he crashed from a height of about 15 metres (49 ft), fracturing his spine. Percy Pilcher took a growing interest in aviation and built a glider called The Bat which he flew for the first time in 1895. Later that year Pilcher met and consulted with Otto Lilienthal, who was the leading expert in gliding; these discussions led to Pilcher building two more hang gliders, The Beetle and The Gull. Based on the work of his mentor Otto Lilienthal, in 1897 Pilcher built a third hang glider called The Hawk with which he broke the world distance record when he flew 250 metres (820 ft).
Wasserkuppe The hang glider lost some importance from the introduction of wing warping in 1902 by the Wright brothers and subsequently of aileron control by the French. When World War 1 ended in 1918, the Treaty of Versailles practically ended engine-driven flights in Germany, 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 air flows in the atmosphere to make them fly farther and faster. These activities on Wasserkuppe promoted a renaissance of gliding aviation. Many of these gliders flown in 1920 were hang gliders in that they were controlled by the pilot's weight shift alone. The first Wasserkuppe glider competition was held in 1920, and from 1924 they were organised by Rhön-Rossitten Gesellschaft. Over the next decade, the contest grew in popularity. As many as 70 glider clubs from Europe sent their best gliders and pilots to compete for duration, altitude and distance prizes, the most coveted prize was that donated by President Paul von Hindenburg. As many as 60,000 spectators dotted the mountain slopes to watch these events. Virtually every European aeronautical engineer of the time tested and modified their aircraft there and reports were generated. Some competing hang glider designers were Alfried Gymnich, Gottlob Espenlaub, Alexander Lippisch, Heinz Schneider, Francis Chardon, Willi Pelzner, and Hans Richter while engineer Henri Mignet was busy in France and Czesław Tański was busy in Poland.
Invention of the flexible wing In 1904 Jan Lavezzari demonstrated a stiffened flexible-wing hang glider in flight at Berck-sur-Mer, France. In 1908, a glider with a triangular control frame and the pilot tethered behind it was demonstrated in the territory of Breslau. These two developments were not reported to aircraft designers, so they bore no influence on the later flexible wing developments. In 1948, aeronautical engineer Francis Rogallo invented a self-inflating wing which he patented on March 20, 1951 as the Flexible Wing, also known as the flexwing and Rogallo wing. Francis Rogallo had first proposed his flexible wing concept to the Langley Research Center in the late 1940s as a simple, inexpensive approach to recreational flying, but the idea was not accepted as a project.
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