Recent Articles



































Hang-gliding



         


recreational activity and competitive sport closely related to gliding, but using much more minimalistic craft often consisting of a metal-framed fabric wing, with the pilot mounted on a harness hanging from the wing frame and exercising control by shifting body weight against a triangular bar also attached to the frame.


Many early experiments with gliding flight throughout the late 19th century were performed using craft that would now be considered hang gliders, by notable pioneers such as Otto Lilienthal, and interest in the sport continued throughout the 20th century.

[Top]

History

See Everard Cunion's history of hang gliding , which incorporates a history of the Wessex Hang Gliding and Paragliding Club (UK) and links to other hang gliding web sites.

Hang gliding was invented, or at least strongly influenced, by the NASA technician Francis Rogallo in the 1960s who had to develop a landing system for the Apollo astronauts return to earth. From there, much of the development of hang gliders occurred in Australia, where the first hang glider manufacturing firms were established. The major breakthrough was the famous flight of Mike Harker from the Zugspitze in Germany in 1972. After that hang gliding became popular all over the world, with the peak in the 1980s. Paragliding has since become a popular alternative to hang gliding, although the two disciplines vary in popularity throughout different countries.

[Top]

Gliders

For a fuller path to hang glider history, follow the threads and leads found in HangGliderHistory group http://groups.yahoo.com/group/HangGliderHistory "Danger" is relative; there is no need to forget fine hang gliders that existed at all stages of the history. An extensive set of hang gliders existed in the late 1960s.

In the '60s and the early '70s many gliders were built that can only be called "extremely dangerous". After that the development, know-how and materials were improved until the first glider came on the market that had all security elements that can still be found today: The "Atlas" (La Mouette, 1978). Then performance increased rapidly. The first true "double surface" glider was the UP "Comet". The first glider without a keel pocket was the Wills Wing "HP" (~1990). In the late 1990s the kingpost on top of the wing was removed to further increase the performance by reducing drag. These gliders are now called "topless gliders". Both topless and kingposted gliders belong to the family of "flex wings", because their frame and sail are a little flexible. This flexibility is required for the weight shift of the pilot to create small differences in the sail's billow, which in turn lets the glider fly to the right or to the left. In parallel the first commercially successful "rigid wing" came on the market (the "Exxtacy") with the leading edge made of carbon fiber, which does not deform at all. The nose angle and wing span is a little higher, and the sail is rather stiff. This generation of gliders is controlled by spoilers typically on top of the wing, while the flex wings are still controlled by weight shift. In both flex- and rigid wings the pilot hangs below the wing without additional fairing except for the harness itself. A third class of hang gliders exists (officially called Sub-Class O-2 by the FAI) where the pilot is integrated into the wing by means of a fairing. This offers the best performance and is the most expensive. All types of gliders can be foot-launched, while landing of some class-2 gliders is only possible on wheels.

[Top]

Flying

Many different forms of hang gliding (and paragliding) are available for pilots, depending on local geography, meteorology, and glider type. Launch techniques include foot-launching from a hill, tow-launching from a ground-based tow system, aerotowing (behind another powered aircraft), and powered harnesses. Other, more exotic launch techniques have also been used successfully, such as hot-air balloon drops for very high altitude launches. In flight, conditions can be either soarable or not soarable (flights in non-soarable conditions are referred to as "sled runs"). Soaring flight can be sustained generally through thermals (caused by solar heating of surface air) or ridge lift (caused by wind rising over geographical features), or both. Flights powered by ridge lift are generally confined to the vicinity of the ridge (which can be very high and long in mountainous regions) or coastal cliff, while thermal flights can extend over great distances and reach thousands of feet in altitude over mountains and flatlands.

[Top]

Safety

While hang gliding has traditionally been considered a highly unsafe sport, gliders themselves are as safe as any other aircraft when constructed by HGMA-certified manufacturers using modern materials. All modern gliders have built-in stall recovery mechanisms (such as luff lines in kingposted gliders) and are designed and tested for as much stability as possible, depending on the performance characteristics desired. Pilot safety is, as in all other forms of aviation, a matter of training (through certified instructors) and self-discipline.

As a backup, pilots carry a parachute with them in the harness. In case of serious problems the parachute is deployed (thrown by hand) and carries both pilot and glider down to earth. The size is typically 30 m2 and the related sink rate should not exceed 6 to 7 m/s (can be less, depending on the state of the glider). This is still sufficient to break some bones, so pilots are encouraged to climb into their control frame after a parachute deployment to allow the frame to absorb some of the impact energy. Some pilots have used rocket-assisted (pyrotechnic or compressed air) parachutes to increase the chances of a successful parachute deployment, but these systems proved unreliable enough that carrying a hand-deployed backup parachute was deemed necessary, so most just carry a single, hand-deployed system. Many hang gliding clubs hold regular parachute deployment clinics to practice this emergency technique on the ground and to encourage regular inspection and re-packing of parachutes.

Pilots also wear helmets and generally carry one or more 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 standard first aid equipment.

[Top]

Performance (2003)

Note: Glide ratio is typically not provided by the manufacturers as it is nearly impossible to measure reliably and depends on many factors like pilot weight, harness design, helmet and so on.

[Top]

Costs (2003)

[Top]

Records

Records fall into nearly the same categories as the ones of the sailplanes and are authorized by the FAI. Technically, the current world record (as of 2003) for "free distance" is held by Manfred Ruhmer with 700,6 km in 2001, but Mike Barber broke the world best with a distance of 704 km (437 miles) on June 19th 2002 in Texas.

[Top]

Competition

Competitions started with "flying as long as possible" and spot landings. With increasing performance cross-country flying replaced them. Usually two to four waypoints have to be passed and photographed. In the late '90s low-power GPS units were introduced and have replaced the photographs completely. Every two years there is a world championship.

[Top]




  View Live Article   This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License