Hang gliding

Hang gliding is a multi-purpose air activity in which a pilot flies an unpowered, light, foot-launchable aircraft called a hang glider. Hang gliding is mainly a recreational air sport, though it has also been used in commerce and for military applications. Most modern hang gliders are made of an aluminum- or composite-framed fabric wing; however vintage hang gliders are still built with a combination of wood, bamboo, and metal. Control of hang gliders is accomplished in many ways; the most common method is by shifting the pilot's mass fore and aft or left or right; however, other devices including modern aircraft flight control systems may be used. The pilot is hung beneath a lifting wing in various arrangements, most commonly a harness hanging from the airframe by flexible hang lines. The Fédération Aéronautique Internationale and national airspace governing organizations play a large part in what occurs in hang gliding.

Although hang gliding started out centuries ago as simply gliding down small hills on low performance hang gliders, modern hang glider technology has the ability to allow pilots to soar for hours, gain thousands of feet of altitude in thermal updrafts, perform aerobatics, and fly cross country over large distances.

Classes

For competitive purposes, there are three classes of hang glider:

The flexible wing hang glider, having flight controlled by a wing whose shape changes by virtue of the shifted weight of the pilot. This is not a paraglider.

The rigid wing hang glider, having flight controlled by spoilers, typically on top of the wing. In both flexible and rigid wings the pilot hangs below the wing without any additional fairing.

Class 2 (designated by the FAI as Sub-Class O-2) where the pilot is integrated into the wing by means of a fairing. These offer the best performance and are the most expensive.

In addition to typical launch configurations, a hang glider may be so constructed for alternative launching modes other than being foot launched; one practical avenue for this is for people who physically cannot foot-launch.

History

The first recorded controlled flights in a hang glider were by German engineer Otto Lilienthal, who published all of his research in 1889, influencing later designers. The hang glider lost some importance through the introduction of wing warping control by the Wright brothers in 1902 and subsequently of aileron control by the French. The evolution of airframes and airfoils resulted in hang gliders from 1895 onwards (Percy Pilcher, Augustus Herring, John J. Montgomery, Carl S. Bates, 1922: Gottlob Espenlaub, 1929: George A. Spratt, and many others. The A-frame for hang gliders, trikes, and ultralights gradually simplified hang glider control.

From 1945 to 1948 Francis and Gertrude Rogallo together were involved with inventing a fundamental fully flexible self-inflating wing "workable at any level of stiffening" also known as Rogallo wing; the wing could be fitted to any airframe or fuselage. On November 23, 1948, Stanford University-trained aeronautical engineer Francis Rogallo and his wife Gertrude Sudgen Rogallo applied together for a patent U.S. Patent 2546078 "Flexible Kite" which was approved in March 20, 1951 as the flexible wing or Rogallo wing, which in 1957 the American space agency NASA began testing in various flexible and semi-rigid configurations in order to evaluate it as a recovery system for the Gemini space capsules and recovery of used Saturn rocket stages. Because NASA were not able to properly solve the unfolding-from-packed condition for the flexible wings for the space-vehicle reentry project, they suspended the high investment in flexible wing projects like the Paresev in 1965 in favor of round parachutes and hard lifting bodies; NASA kept the files opened on the Rogallo wings and further attention was eventually given to the Rogallo wing. The various stiffening formats and the wing's simplicity of design and ease of construction, along with its capability of slow flight and its gentle landing characteristics, did not go unnoticed by hang glider enthusiasts, who were already building and flying rigid wing hang gliders. Some designers rapidly adapted Rogallo's flexible wing onto elementary flexible wing hang gliders, but performance and control remained a challenge. Barry Hill Palmer explored four levels of control of the Rogallo wing hang glider in 1960-1962 and went on to develop a powered hang glider. In 1962, Mike Burns developed the delta winged manned kite SkiPlane in Australia from information about the Rogallo wing from NASA; then fellow countryman John Dickenson, who had been flying a gyrocopting wing in 1963, set out to build a manned water ski-kite that could be released at altitude for a glide to a safe landing. Dickenson called it the "Ski Wing" ; although its gliding performance was not impressive; he finally came to an effective use of the trussed trapeze that had been given to aviation for hang gliders by at least George A. Spratt and also by manned kiting; by October of 1964 he reached the ornamental design for the main lifting wing that had been priorly achieved in the hanging-piloted Paresev 1B wing designed by Charles Richard of NASA. The Dickenson ski-kite's low weight, increased control, and portability was used in water-ski kiting from that point forward. Then Bill Bennett and Bill Moyes advanced the Dickenson format of Rogallo wing ski-kite and brought it fully into foot-launch hang gliding by 1971 and 1972. The flowering of Rogallo hang gliders stemming from the Barry Palmer and the Dickenson-Bennett-Moyes influence along with other influences formed a kind of renaissance in popular hang gliding in the 1970s when scores of manufacturers and flying meetings occurred. For example, the Swallowtail hang glider was featured in the 1976 movie Sky Riders (filmed in Greece during 1975) starring James Coburn, Robert Culp, Susannah York, and Charles Aznavour. After filming of the action was complete, the Wills Wing team toured Europe and stopped by in England to win the British Championships at Mere, Wiltshire in August 1975. The mechanics of George Spratt's 1929 triangle control bar with his pendulumed pilot mass-shifting contol into hang gliding and Charles Richard's foldable Paresev 1B wing, allowed foldable hang gliders that dramatically reduced difficulty in control, storage, transport, assembly, and repair. Dickenson's efficiencies with the help of aeronautical engineer and aviation-standards manufacturer Mike Burns of the NASA-inspired SkiPlane were further refined and brought to the world market by Austalian sportsmen, ski-kite fliers, and businessmen Bill Bennett and Bill Moyes, who significantly improved hang gliders and hang gliding trends along with hundreds of other innovators around the world. Richard Miller was a prime mover for many kinds of hang glider designs in the United States. Mike Harker strongly introduced hang gliding to Europe for the modern renaissance in 1973. The Roy Haggard Dragonfly hang glider introduced a new generation of hang glider design that spelled the demise of the Paresev-lined wing or "standard Rogallo" wing which had become infamous for its luffing-dive safety challenges. High-level engineering from 1975 forward brought an unending series of improvements in hang gliders; most hang gliders, not all, continued to use the simple cabled or stiff-braced triangle control bar (aka "A-frame") and pendulumed mass-shifting control that was gifted to aviation and hang gliding mechanics by George A. Spratt in 1929, if not by others before him like Gottlob Espenlaub and Percy Pilcher.

Training & Safety

Hang gliding has traditionally been considered an unsafe sport, ever since its inception. Otto Lilienthal died of a fractured spine from a glider crash after a gliding career lasting only five years. Modern hang gliders are very sturdy when constructed by HGMA, BHPA, DHV or other certified manufacturers using modern materials, though they remain lightweight craft that can be easily damaged, either through misuse or by continued operation in unsafe wind/weather conditions. All modern gliders have built-in stall recovery mechanisms (such as luff lines in kingposted gliders). Nevertheless, the inherent danger of gliding at the mercy of unpredictable thermal and wind currents, has resulted in numerous fatal accidents and many serious injuries over the years, even to experienced pilots, and the resultant adverse publicity has affected the popularity of hang gliding.

As a backup, pilots carry a parachute in the harness. In case of serious problems the parachute is deployed and carries both pilot and glider down to earth. Pilots also wear helmets and generally carry other safety items such as hook knives (for cutting their parachute bridle after impact or cutting their harness lines and straps in case of a tree or water landing), light ropes (for lowering from trees to haul up tools or climbing ropes), radios (for calling for help) and first-aid equipment.

An aspect that has dramatically improved the safety of the modern hang glider is pilot training. Early hang glider pilots learned their sport through trial and error. Many of those errors have led to effective training techniques and programs developed for today's pilot, with emphasis on flight well within safe limits, as well as the discipline to cease flying when weather conditions are unfavorable.