Hang gliding
|
|
Hang gliding is one of the windsports. It is a recreational or competitive sport closely related to gliding, but using a much simpler 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.
Early experiments with gliding flight were made throughout the late 19th century by pioneers such as Otto Lilienthal. These craft would now be considered as hang gliders.
| Contents |
History
Modern hang gliding was invented, or at least strongly influenced, by the NASA technician Francis Rogallo in 1948 with the invention of the Flexkite. This device was considered as a possible landing system for the 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. Hang gliding then became popular world-wide, with the peak in the 1980s. Paragliding has since become an alternative to hang gliding.
Gliders
For a fuller hang glider history see the Hang Glider History group http://groups.yahoo.com/group/HangGliderHistory.
In the 1960s and the early 1970s many gliders were built that can only be called dangerous. The first notable hang gliders to abandon the Rogallo wing were Icarus I and Icarus II. These were rigid biplane flying wing designs by Taras Kiceniuk, Jr.. Icarus V was the precursor to the modern hang glider. It was essentially a monoplane version of the previous Icarus designs. All of the hang gliders in the Icarus series had hand-controlled rudders and the pilot flew in a reclining position (rather than a prone position as with other hang gliders). Although many Icarus II and Icarus V gliders were built from plans sold by Kiceniuk, they were never commercially produced. In 1978, the Atlas (La Mouette) entered the market. It resembled Icarus V but had a flexible wing and no rudders. The pilot also flew in a prone position as with the Rogallo wing hang gliders. The Atlas had all of the security elements that can still be found today.
Hang glider performance then increased rapidly. The first true "double surface" glider was the UP "Comet" designed by Roy Haggard (1980). Virtually all gliders over the next decade were refinements of the Comet. The first glider without a keel pocket was the Wills Wing "HP" (1984). Bob Trampenau of Seedwings introduced the VG (variable geometry), which was copied on most other gliders. 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 turn to the right or to the left.
In parallel the first commercially successful "rigid wing" came on the market (the "Exxtacy") with a leading edge of carbon fiber, which does not deform. 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 flexible and rigid wings the pilot hangs below the wing without any additional fairing. 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 some class-2 gliders is only possible on wheels.
Flying
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.
A handy FAQ can be found here: [1] (http://members.aol.com/dfscinc/faq.html)
Safety
While hang gliding has traditionally been considered a highly unsafe sport, the gliders themselves are as safe as any other aircraft when constructed by HGMA (Hang Gliding Manufacturing Association)-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 (but 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 first aid equipment.
Another issue that has dramatically improved the safety of the modern hang glider pilot is training. Early hang glider pilots learned their sport through trial and error. Much of that very error has lead to effective training techniques and programs developed for todays novice pilot. While the pitch and roll stability built into modern hang gliders helps prevent high altitude problems in flight, these features require altitude to take effect. If a stall or slipping turn happens while close to the ground or other obstacle then the glider will not have the time to self correct. This has placed the prevention of accidents during launch and landing as the main priority of early training.
Anyone considering taking up the sport of hang gliding should therefore join a local club and/or national Hang Gliding Association and ensure they get proper instruction.
Performance (2003)
- Topless gliders: glide ratio ~15:1, speed range ~30 to >100 km/h, best glide at ~45 to 50 km/h
- Rigid wings: glide ratio ~18:1, speed range ~ 35 to > 100 km/h, best glide at ~50 to 55 km/h
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.
Costs (2003)
- Rigid wings: ~10000 Euro
- Topless gliders: 5-6000 Euro
- Intermediates: ~4000 Euro
- Beginner gliders: < 3000 Euro
- Harness: 500 - 1500 Euro
- Parachute: ~ 500 Euro
- Instruments: 200 - 1000 Euro
- School: 2-3 lessons (introductory package) 3-400 Euro
- School: 10 lessons (full course) 8-1000 Euro
Records
Records fall into nearly the same categories as those for sailplanes and are authorized by the FAI. Technically, the current world record(s) (http://records.fai.org/hang_gliding/) (as of 2005) for "free distance" is held by Manfred Ruhmer with 700,6 km in 2001, but Mike Barber has flown a distance of 704 km (437 miles) on June 19th 2002 in Texas.
Competition
Competitions started with "flying as long as possible" and spot landings. With increasing performance cross-country flying replaced them. Hang gliding competitions are like a 3d boat race in the sky where the clouds act like gas stations. Usually two to four waypoints have to be passed with a landing at a goal. In the late '90s low-power GPS units were introduced and have replaced the photographs completely. Every two years there is a world championship. The Rigid and Women's World Championship is in 2006 and is hosted by Quest Air in Florida (http://www.questairforce.com/)Big Spring, Texas is hosting the 2007 World Championship.
Related sports
The two related sports are: gliding, in which the gliders have full control surfaces and an enclosed cockpit, and paragliding, where a sophisticated kind of parachute is used
External links
- United States Hang Gliding Association (http://www.ushga.org/)
- Hang Gliding Federation of Australia (http://www.hgfa.asn.au/)
- Hang gliding links (German) (http://www.sports-funline.de/index.html)
- German Hanggliding Association (English) (http://www.dhv.de/english/index.html)
- HangGliderHistory group(English) (http://groups.yahoo.com/group/HangGliderHistory)
- The Oz Report - Worldwide Hang Gliding eZine and blog (http://www.ozreport.com/)
- Hang Gliding Photos (http://www.hangglide-utah.com/cgi-bin/photos.pl)
- Hang Gliding and Paragliding Commission of FAI (http://www.fai.org/hang_gliding/)
- Current hang gliding records (http://records.fai.org/hang_gliding/)
- 2005 World Championship Results (http://weshill.customer.netspace.net.au/)fr:Deltaplane
it:Deltaplano ja:ハンググライダー nl:Deltavliegen pl:Lotnia sr:Змајарство de:Hngegleiter