Paragliding

From Freepedia

Paragliding (known in some countries as parapenting) is a recreational and competitive flying sport. A paraglider is a free-flying, foot-launched aircraft, the way a hang glider is. It is quite different from the parachutes used in parasailing, which is a passive amusement ride where the participant is towed on a line behind a boat.

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Contents

Gliders

Modern paragliders began as rectangular skydiving parachutes flown from hills. They have evolved dramatically in the last twenty years to be extremely high tech aircraft in both design and materials. Paragliders are optimized for glide performance, turning behavior, and safety. Since they are not opened from freefall at terminal velocity) but rather launched from a hillside, they do not have to be as strong as skydiving parachutes. They are lighter and larger, giving them much better performance gliding and climbing in thermals. These paragliders have reasonable gliding characteristics and are quite controllable by use of cords which are held in the pilot's hand as he or she sits in the harness. Shifting one's weight also steers the paraglider.

The paraglider wing is a self-inflating structure. It consists of a row of cells, most of them open at the front and all of them closed at the back, joined together side by side. Moving through the air keeps them inflated because air goes in the front but can't get out the back. The cells are cut into the same cross-sectional shape as an aeroplane wing and it is this "aerofoil" section that produces the lift. The pilot is supported underneath the wing from a web of lines, each with the strength to support the pilot. The lines are then attached to risers, straplike devices, that are attached to the pilot's harness.

Solo paragliders typically have an area of 20-30 m2 and weigh 5-7 kg. Glide angles range from 7:1 to 10:1 and top speeds from 45 to 65 km/h.

Tandem paragliders, designed to carry the pilot and one passenger, are larger but otherwise similar.

Comparing paragliders to hang gliders

The sports of hang gliding and paragliding are essentially the same. Both aircraft can be footlaunched from mountains or towed aloft. Both have variations with engines that are flown in much smaller numbers than the unpowered kind.

Hang gliders and paragliders each have advantages and disadvantages relative to the other:

Hang gliders are better at flying in strong winds because they fly faster through the air. This means it takes a stronger wind before a hang glider is no longer able to make forward progress against the wind (a situation known as being "parked"). Not being able to make progress against the wind can be dangerous if it prevents you from reaching a safe place to land. With both aircraft, prudence is necessary about the amount of wind expected during the flight; the threshold windspeed for problems is higher with a hang glider.

Hang gliders perform better and are safer in strong turbulence. Paragliders are vulnerable to collapses of the fabric wing, which require pilot control, and in strong turbulence they can be very difficult for even expert pilots to control. Both aircraft have limits with regard to safe amounts of turbulence that require attention not to exceed; in neither case is the limit very high, in the world of atmospheric turbulence, but again the limits are higher for hang gliders than for paragliders.

Paragliders are easier to transport. They pack up in to a large rucksack weighing less than 50 lbs (22 kg) including harness, helmet, flight suit, everything. The rucksack can be taken as checked baggage on a commercial airline, allowing paragliders to fly their own wings at sites all over the world. The rucksack can be carried up a mountain by a fit person, allowing safe launching from many places not accessible by roads. Most hang gliders require a lumber rack on a car or truck for transport; one model folds up small enough to take as checked baggage on an airplane, but most people don't fly that model.

Hang gliders are easier to launch in strong winds (when a paraglider pilot is often best advised not to launch at all). Paragliders are easier to launch in very light winds.

Paragliders are easier to land. An expert can land a paraglider in a very small field, 50 feet (15 meters) on a side or less, as long as there aren't tall obstacles around the field. A hang glider takes more room, a hundred yards or more, and even experts have minor accidents landing with some regularity.

Paragliders are safer in mild conditions because they are easier to launch in light winds and easier to land.

Paragliding is easier to get started at than hang gliding; the amount of training required for your first mountain solo is a lot less. To be an expert at either sport requires similar numbers of flying hours and a lot of continuing education.

Paragliders climb the best in narrow thermals, simply because they fly more slowly, so they can make tighter circles. Paraglider pilots routinely "core up" inside circling hang gliders and sailplanes.

Hang gliders (and sailplanes) have better (or much better) glider performance than paragliders, meaning from a given altitude in the same wind they will fly farther over the ground before they have to land.

For "cross country" flying (see description below), hang gliders have the advantage of flying faster with better glide ratios, which means they can cover more ground and they are able to glide safely to more distant landing fields. Paragliders have the advantage of requiring a much smaller space to land, so in many place there are many more options for where you can land if you need to. Also, if you land some distance from a road, the paraglider packs up into its rucksack and is much easier to carry than the hang glider. People have hiked tens of miles out of the mountains carrying their paraglider, where as hang gliders get abandoned in similar circumstances, requiring difficult and costly retrieval later.

Flying

Launching is usually done in anabatic wind, which blows uphill, or zero wind. A launch in more than a very light tail-wind is not possible. In calm morning or evening air a pilot may enjoy a "sled ride", a smooth flight down to a landing area. During the day, when the sun heats the ground and the ground heats the air next to it, updrafts of warm air called thermals are present, stirring up the lower atmosphere. A paraglider pilot, like a hang glider or sailplane pilot, typically seeks out these thermals and uses them to gain altitude. Any unpowered aircraft is always descending through the air, but if the air is moving up faster than the aircraft is descending, the aircraft will be climbing relative to the ground.

When a pilot finds a thermal, he or she begins to fly in a circle, trying to center the circle on the strongest part of the thermal, the place where the air is going up the fastest. This circling isn't a one time thing; thermals are not always politely organized and may zig, weave and roil as they climb through the atmosphere. A good pilot is adjusting the position of this circle constantly to try to stay in the area of strongest lift. Most pilots carry an instrument called a variometer that communicates with beep sounds and a visual display the rate of climb. A variometer makes it easier to center one's circles and climb effectively in thermals.

On a blue sky day, when a pilot reaches the top of a thermal climbing slows or stops and the air often becomes turbulent. The pilot will normally leave in some direction ("go on glide") either trying to explore the place they are flying in or simply hoping to locate another thermal.

On days with cumulus clouds, each cloud is usually at the top of a thermal. Large or fast growing cumulus clouds, and especially thunderstorms, may have very strong lift under them, and hang and paragliders must be cautious not to get sucked up into such a cloud. Usually if there are strongly growing cumulus clouds about it's a good day to stay on the ground.

Overcast days normally have little thermal activity. Sled rides are possible if it's not raining. It's important to be aware of the possibility of thunderstorms that are embedded in the overcast and therefore hard to see.

Another kind of lift used by paragliders, hang gliders and sailplanes is "ridge lift", also known as "orographic lift". This simply refers to wind blowing up a hill, cliff or mountain, like a current of water. As with thermals, if the air is going up faster than the glider is sinking through the air, the glider can gain or maintain altitude indefinitely.

Conditions

Paragliders (or "Parapentes" in French) have a low top speed, hence are suited to flying in winds of under 25 km/h and relatively smooth air conditions. The non-rigid structure of paragliders relies on a constant angle of attack to maintain the shape and profile of the wing section. Turbulent air changes the angle of attack and can deflate part or all of a wing while in flight. "Collapses" are typically easy to deal with but require some training to manage correctly.

Paragliders are suitable for mountain flying in low-wind conditions, and are often flown in thermally active areas or coastal locations where a sea-breeze is prevalent, allowing ridge soaring.

World records

As of April 2004, the World record distance flown was 423.4 km, set by Canadian William Gadd on 21 June 2002 from the town of Zapata, Texas, United States.

Disciplines

Early paragliders had very poor performance and it was generally only possible to fly from the top of the hill to the bottom. As the paraglider technology developed more possibilities opened up: staying up for as long a time as possible (maximum duration), getting as high as possible (maximum altitude gain) and flying as far as possible (maximum distance). The sport has developed further and now has several sub-disciplines each with its own adherents and competition circuit. These are:

Soaring 
Flying for the simple pleasure of flying, anywhere from sand dunes to mountain ridges, usually at well understood flying sites.
Cross country (XC) 
Taking off and trying to fly as far as possible from the take off site. Good XC pilots are experts at finding and using different types of lift such as thermals and can fly 10-200km in a day depending on the landscape and weather conditions.
Racing 
Typically flying defined tasks as a race against others. Competition pilots use special high-performance gliders that demand a high level of pilot skill to fly and can complete 30-100km races in one to three hours. The world's best racers compete in the Paragliding World Cup and the Paragliding World Championship.
Accuracy 
Spot landings. The top pilots can reliably landing within ten centimetres of the target every single time.
Acro (acrobatics) 
Doing tricks such as loops and wingovers. See Acromania for a description of the various tricks. In acro competitions pilots score points for the difficulty of the tricks they do and how well they are performed.
Vol-rando and para-alpinism 
Walking or climbing up a hill or mountain with a lightweight paraglider for the pleasure of the ascent and then descending using a paraglider. A complete set of paragliding equipment (wing, harness, helmet, etc.) typically weighs 15-20 kg, the equivalent specialist lightweight kit can weigh as little as 5 kg.
Vol-biv (vol bivouac) 
Doing multiday trips combining paragliding, walking and camping. Vol-biv trips last from a couple of days to several weeks.
Record hunting 
Several world records are recognised, typically for flying as far as possible or completing a defined task as quickly as possible. Breaking a world or national record nowadays requires a huge amount of planning and preparation, pilot skill, the very best equipment, as well as a bit of luck on the day.
Adventure flying 
Exploring the corners of the world with a paraglider, demanding a high level of self-reliance and commitment. Adventure pilots fly where no-one else has done before and often where an unintended landing would be extremely serious due to inhospital terrain or remoteness.

Pilots typically start with soaring, whether thermal or ridge soaring. Some move on to cross country, vol-rando, acro or accuracy flying, while many are content to simply get in the air at their local flying site. Experienced cross country pilots might then explore racing or vol-biv, whereas those who enjoy vol-rando might try para-alpinism. Acro paragliding is an emerging sport and very much the realm of extremely skillful pilots. Record hunting and adventure flying is for those at the top of their game.

Safety

Paragliding, like other "high consequence" sports such as rock climbing and mountaineering, is as safe or dangerous as you make it. If you get proper training, fly conservative equipment, stay aware of your limitations and are cautious about the conditions you choose to launch in, it becomes very benign. The more ambitious a pilot is in any of these areas, the more risks are possible, but highly skilled pilots can do a lot of things safely while always operating within their limitations.

A big part of learning any of these sports is making it safely through the learning period when you don't realize how much you still don't know. It's common to see relatively new pilots eager to launch their paragliders while other pilots with thousands of flight hours are waiting patiently on the ground for the conditions to change in some way. It's very valuable when you are learning to observe what the experienced pilots are doing, ask them about it, and take their answers seriously even if you don't understand them yet.

Although paragliding is classified as a high-risk sport, technological advances in the design of paraglider canopies have significantly reduced the number of recorded incidents since the pioneering days of the 1980s. On average there are between one and three fatalities a year in Great Britain, or slightly less than 1 fatality per 1,000 pilots in the United States. Though many fatalities involve more experienced pilots using faster, high-performance wings that are less stable in the air, less experienced pilots flying more stable wings are not immune. The most common minor injuries are twisted ankles and back injuries sustained during take-off and landing.

Ninety percent of all injuries occur in the first 10 flights and are, typically, to the lower leg. Once a pilot has achieved a full license (after 40 to 60 high-altitude flights) the injury rate drops significantly until 500 to 1000 flights have been completed. Then the injury rate spikes again and, typically, the injuries are very serious or fatal.

Trained Pilots often take a safety course where they cause a collapses of the wing on purpose to train for the event this happens accidentally. Usually these safety trainings are taken while in very high altitude or over a lake, while keeping radio contact with a trained instructor. In some countries, such trainings are needed to obtain higher-level certificates.

In the early years harnesses were made of a simple parachutist harness, possibly with a wooden board to make the flight easier on the legs, but now safety measures such as back-protectors made of thick impact absorbing foam are commonplace. LIke helmets or other protective geat, there are limits to the strength of impact that can safely be absorbed by a foam back protector in a paragliding harness.

Another safety measure adopted by paragliding pilots is the use of a reserve parachute. A reserve can be deployed in extreme circumstances such as when the wing collapses and becomes knotted into itself without hope of recovery. Fortunatley such events are rare. On most modern wings a partial collapse at high altitude is no big deal. The glider will recover quickly with gentle pumping on the brakes, losing little altitude.

Learning to fly

A beginner should learn from a fully-qualified instructor. Paragliding is aviation, and pioneers in aviation have always had high fatality rates. You don't want to be a pioneer. Teaching yourself is extremely dangerous.

One of the nine fatalities in the United States in 2003 was a self-taught pilot attempting to fly in high winds by tethering to a fixed object on the ground. A bystander was also seriously injured in this accident. Fixed-rope towing and tethering with fixed ropes to objects is extremely dangerous and has resulted in several other serious injuries and fatalities. Training is essential in any form of aviation. Pilots should not sell used equipment to people who do not have proper training.

Safe towing requires a weak link, a proper tow device and training for both the pilot and the tow operator.

History

The origin of paragliding has roots in the sport of parachuting. In the early 1960’s, American parachutist Pierre Lemoigne was successful in cutting slots in the round parachute canopy to allow for air to flow through the canopy. This had a dramatic effect on the lift to drag ratio and allowed the pilot to steer the chute in a predictable manner.

In 1962, Walter Newmark of England took note of Lemoigne’s design and modified it so that the chute could be towed aloft. During the 1960s, parascending became a popular sport among the English. Newmark was responsible for the creation of the British Association of Parascending in the early 1970’s.

In 1964, Domina Jalbert of Florida invented a square canopy called the Ram Air Para Foil. The Ram Air worked by allowing air to pass through the double surface glider allowing for better maneuverability and increased lift. Walter Newmark soon adopted this canopy for his parascending activities. Using specially designed ram-air parachute canopies, instead of wings of aluminium and dacron, paraglider pilots launch, glide and soar in much the same way that hang-glider pilots do.

Not until the 1970s did the sport take off. Gerard Bosson, André Bohn and Jean Claude Bétemps introduced paragliding at the 1979 World Hang Gliding Championships.

The first pioneering foot-launched flights on gliding parachutes were made during the mid-1960s by David Barish in the U.S. The sport of recreational paragliding as we know it today was born in Mieussy, France, in 1978 and grew rapidly during the mid-1980s in the French and Swiss Alps as commercial manufacturers improved the glider designs to optimize them for soaring flight.

See also

External links

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