HANG GLIDING

'Hang gliding' is an air sport, hobby, a vocation, passive experience, or even profession wherein humans pilot their hang gliders. It can be recreational or competitive. Although it started out as simply gliding down small hills on low performance kites, hang gliding has evolved the ability to soar for hours, gain thousands of feet of altitude in thermal updrafts, perform aerobatics, and fly cross country over large distances. The sport is closely related to paragliding and gliding (flying sailplanes) but usually using a much simpler and less expensive craft often consisting of an aluminum- or composite-framed fabric wing, with the pilot mounted on a harness hanging from the wing frame and exercising control by shifting body weight; there are alternatives to such arrangements and choices of materials. Sport categories have evolved where complex and expensive systems may also be used. Sport, hobby, and a vocational hang gliding may involve very low cost constructions or extremely expensive assemblies. Professional hang gliding can involve shows, instruction, selling, advertising, etc.

Contents
Classes
History
Training & Safety
Launch
Soaring Flight
Thermals
Ridge lift
Mountain wave
Convergence
Cross-country flying
Performance (2006)
Costs (2003)
Instruments
Variometer
Radio
GPS
Records
Competition
Related sports
Q & A
References
External links

Classes


Modern 'flexible wing' hang glider.

In one perspective there are three classes of hang glider:

★ The flexible wing hang glider, having flight controlled by a wing whose shape changes in 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.
The most used definitions have that hang gliders can be foot-launched, but landing some class-2 hang gliders is only possible on wheels. Beyond regulated hang gliding, 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.[1]
In another perspective there are more than three classes of hang glider. Consider a multi-plane rigid-winged hang glider that does not "shape change" in virtue of shifted pilot weight; Otto Lilienthal (a German pioneer of hang gliding) introduced this class of hang glider. Further, the rotary-wing hang gliders, though not popular, are in a class by themselves. Paragliders can be seen simply as one class of hang glider in alternative perspectives.

History


Main articles: History of hang gliding

Training & Safety


Learning to hang glide.

Hang gliding has traditionally been considered an unsafe sport, ever since its inception. Otto Lilienthal himself died of a fractured spine from a glider crash after a gliding career lasting only five years. Modern hang gliders are fairly sturdy when constructed by HGMA, BHPA or DHV
★ -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) 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 perhaps most importantly, self-discipline. Nevertheless, the inherent danger of gliding at the mercy of unpredictable thermal and wind currents, often in proximity to dangerous terrain, 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.
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. 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 conditions are unfavorable.

Launch


Launch of a hang glider

Launch techniques include foot-launching from a hill, tow-launching from a ground-based tow system, aerotowing (behind a 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. Flights in non-soarable conditions are referred to as "sled runs".

Soaring Flight


Good gliding weather. Well formed cumulus clouds, with darker bases, suggest active thermals and light winds.
Good gliding weather. Cumulus clouds with dark flat base.

Glider pilots can stay airborne for hours. This is possible because they seek out rising air masses (lift) from the following sources:
Thermals

The most commonly used source of lift is created by the sun's energy heating the ground which in turn heats the air above it. This warm air rises in columns known as thermals. Soaring pilots quickly become aware of visual indications of thermals such as: cumulus clouds, cloud streets, dust devils and haze domes. Also, nearly every glider contains an instrument known as a variometer (a very sensitive vertical speed indicator) which shows visually (and often audibly) the presence of lift and sink. Having located a thermal, a glider pilot will circle within the area of rising air to gain height. In the case of a cloud street thermals can line up with the wind creating rows of thermals and sinking air. A pilot can use a cloud street to fly long straight-line distances by remaining in the row of rising air.
Ridge lift

Another form of lift occurs when the wind meets a mountain, cliff or hill. The air is deflected up the windward face of the mountain forming lift. Gliders can climb in this rising air by flying along the feature. Another name for flying with ridge lift is slope soaring.
Mountain wave

The third main type of lift used by glider pilots is the lee waves that occur near mountains. The obstruction to the airflow can generate standing waves with alternating areas of lift and sink. The top of each wave peak is often marked by lenticular cloud formations.
Convergence

Another form of lift results from the convergence of air masses, as with a sea-breeze front.
More exotic forms of lift are the polar vortexes which the Perlan Project hopes to use to soar to great altitudes [2]. A rare phenomenon known as Morning Glory has also been used by glider pilots in Australia.[2]
Cross-country flying

Once the skills of using thermals to gain altitude have been mastered, pilots can glide from one thermal to the next to go ‘cross-country’ (‘XC’). Potential thermals can be identified by land features which typically generate thermals, by soaring birds or by cumulus clouds which mark the top of a rising column of warm, humid air as it reaches the dew point and condenses to form a cloud.

Performance (2006)


With each generation of materials and with the improvements in aerodynamics, the performance of hang gliders has increased. One measure of performance is the glide ratio. For example, a ratio of 12:1 means that in smooth air a glider can travel forward 12 meters while only losing 1 meter of altitude.

★ Topless gliders: glide ratio ~17:1, speed range ~30 to >145 km/h, best glide at ~45 to 60 km/h

★ Rigid wings: glide ratio ~20:1, speed range ~ 35 to > 130 km/h, best glide at ~50 to 60 km/h
''Note:'' Glide ratio is typically not provided by the manufacturers as it is nearly impossible to measure reliably and because the pilot is in the airstream (unlike in a sailplane) depends on many factors like pilot weight, pilot position, harness design, helmet, placement of instruments and so on.
'Ballast'
The extra weight provided by ballast is advantageous if the lift is likely to be strong. Although heavier gliders have a slight disadvantage when climbing in rising air, they achieve a higher speed at any given glide angle. This is an advantage in strong conditions when the gliders spend only little time climbing in thermals.

Costs (2003)



★ Rigid wings: ~10000 Euro (approx. $13400US)

★ Topless gliders: 5-6000 Euro (approx. $8100US)

★ Intermediates: ~4000 Euro (approx. $5400US)

★ Beginner gliders: < 3000 Euro (approx. $4000US)

★ 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) 800-1000 Euro

Instruments


In order to maximize a pilot's understanding of how the hang glider is flying, most pilots carry a series of instruments. The most basic being a variometer and altimeter--often combined. Some more advanced pilots also carry airspeed indicators and radios. When flying in competition or "cross country" pilots often also carry maps and/or GPS units. Hang gliders do not have instrument panels as such, so all the instruments are mounted to the control frame of the glider.
Variometer

Vario-altimeter

People can sense the acceleration when they first hit a thermal, but they cannot detect the difference between constant rising air and constant sinking air, so they turn to technology for help. A variometer is a very sensitive vertical speed indicator; in other words, the variometer indicates climb rate or sink rate with audio signals (beeps) and/or a visual display. These units are generally electronic, vary in sophistication, and often include an altimeter and an airspeed indicator. More advanced units often incorporate a barograph for recording flight data and/or a built-in GPS. The main purpose of a variometer is in helping a pilot find and stay in the ‘core’ of a thermal to maximize height gain, and conversely indicating when he or she is in sinking air and needs to find rising air.
Variometers are sometimes capable of electronic calculations based on the 'MacCready Speed Ring' to indicate the optimal speed to fly for given conditions. The Mac Creadytheory solves the problem of how fast a pilot should cruise between thermals, given both the average lift the pilot expects in the next thermal climb, as well as the amount of lift or sink he encounters in cruise mode. Some electronic variometers make the calculations automatically, after allowing for factors such as the glider's theoretical performance (glide ratio), altitude, hook in weight and wind direction.
2m-band radio

Radio

Pilots use radio for training purposes, and for communicating with other pilots in the air – particularly when traveling together on cross-country flights.
Radios used are PTT (push-to-talk) transceivers, normally operating in or around the FM VHF 2-metre band (144–148 MHz). Usually a microphone is incorporated in the helmet, and the PTT switch is either fixed to the outside of the helmet, or strapped to a finger.
GPS

GPS (global positioning system) is a necessary accessory when flying competitions, where it has to be demonstrated that way-points have been correctly passed.
It can also be interesting to view a GPS track of a flight when back on the ground, to analyze flying technique. Computer software is available which allows various different analyses of GPS tracks (e.g. CompeGPS).
Other uses include being able to determine drift due to the prevailing wind when flying at altitude, providing position information to allow restricted airspace to be avoided, and identifying one’s location for retrieval teams after landing-out in unfamiliar territory.
More recently, the use of GPS data, linked to a computer, has enabled pilots to share 3D tracks of their flights on Google Earth. This fascinating insight allows comparisons between competing pilots to be made in a detailed 'post-flight' analysis.

Records


Records fall into nearly the same categories as those for sailplanes and are sanctioned by the FAI. The current world record(s) (as of 2005) for "free distance" is held by Manfred Ruhmer with 700.6 km (435.3 miles) in 2001, but Mike Barber has flown an uncertified distance of 704 km (437 miles) on June 19 2002 in Zapata Texas.

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 with a landing at a goal. In the late 90s low-power GPS units were introduced and have completely replaced photographs of the goal. Every two years there is a world championship. The Rigid and Women's World Championship in 2006 was hosted by Quest Air in Florida. Big Spring, Texas is hosting the 2007 World Championship. Hang gliding is also one of the competition categories in World Air Games organized by Fédération Aéronautique Internationale (World Air Sports Federation - FAI). The FAI also has a chronology of the FAI World Hang Gliding Championships.[3]

Related sports


The related sports are gliding, in which the gliders have full control surfaces and an enclosed cockpit, and paragliding, where the pilot is sitting on a harness suspended below a fabric wing.
== Comparison with Paragliders ==
Paragliding and hang gliding are closely related sports: foot-launched gliders with flexible wings, with options for tow launching and for powered flight and there is sometimes confusion about the differences. Beyond sport definitions and sporting association class definitions, there is a perspective that simply treats paragliders as a proper subset of hang gliders (as an over class of aircraft apart from the influence of sporting classes).
The main differences between the 'two proper subsets' of generalized hang gliders are:
Paragliders Hang gliders
''Wing structure:'' entirely flexible, with shape maintained purely by the pressure of air flowing into the wing in flight and the tension of the lines supported on a rigid frame which determines its shape and thus does not collapse in turbulence
''Pilot position:'' sitting ‘supine’ in a seated harness usually lying ‘prone’ in a cocoon-like harness suspended from the wing. Seated, and 'supine' are also possible
''Speed range (stall speed – max speed):'' slower – hence easier to launch and fly in light winds, can get into trouble when winds pick up, poor wind penetration and no pitch control, cannot dive for speed, although some pitch variation can be achieved with speed bar. faster – much faster, up to 90+ mph, hence easier to launch and fly in stronger conditions with better wind penetration, and can out run bad weather, full pitch control
''Glide angle:'' poorer glide performance makes long-distances more difficult better glide performance enables longer-distance flying, 430+ mile records
''Landing-out:'' smaller space needed to land, offering more landing options from cross-country flights. Also easier to carry back to the nearest road longer approach & landing area required, but can reach more landing areas due superior glide range
''Learning:'' quicker to get ‘into the air’ with most skills learned in the air; flying tandem with an instructor is rarely necessary during instruction basic control skills are learned in ground school, and in flights close to the ground prior to high flights;
''Convenience:'' pack smaller (easier to transport and store); lighter (easier to carry); quicker to rig & de-rig; transported in the trunk of a car more awkward to transport & store; longer to rig and de-rig; transported on the roof of a car
''Cost:'' cheaper but less durable more expensive but more durable

Q & A


Q1. Is there hang gliding activity outside of organized and regulated sport? Yes. Some people build and fly experimental hang gliders and choose not to enter the sports arena.


References


1. Dan Buchanan: [1]
2. A Guide to the Morning Glory at www.dropbears.com
3. Chronology of the FAI World Hang Gliding Championships[3]

External links



United States Hang Gliding and Paragliding Association - USHPA Official US Association.

Hang Gliding Org webs #1 hang gliding community, videos, images, forum, news.

Hang glider bible

Current hang gliding records

DMOZ Open Directory category: Hang Gliding

Hang Gliding Photo Gallery

The Oz Report - Worldwide Hang Gliding eZine and blog

Hang Gliding Photos

Hang Gliding Faq

The Scottish Hang-gliding & Paragliding Federation

The Longest Running Hang Gliding Competition in the World

Info about Hang Gliding

The British Hang Gliding and Paragliding association

The Hang Gliding Federation of Australia Governing body in Australia for Hang Gliding, Para-Gliding and Microlights

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