Paraglider Mod

[Quinton Hebenstreit]

Paraglidingis the recreational and competitive adventure sport of flying paragliders: lightweight, free-flying, foot-launched glider aircraft with no rigid primary structure.[1] The pilot sits in a harness or in a cocoon-like 'pod' suspended below a fabric wing. Wing shape is maintained by the suspension lines, the pressure of air entering vents in the front of the wing, and the aerodynamic forces of the air flowing over the outside.

Despite not using an engine, paraglider flights can last many hours and cover many hundreds of kilometres, though flights of one to five hours and covering some tens of kilometres are more the norm. By skillful exploitation of sources of lift, the pilot may gain height, often climbing to altitudes of a few thousand metres.

In 1954, Walter Neumark predicted (in an article in Flight magazine) a time when a glider pilot would be "able to launch himself by running over the edge of a cliff or down a slope ... whether on a rock-climbing holiday in Skye or skiing in the Alps."[3]

In 1961, the French engineer Pierre Lemongine produced improved parachute designs that led to the Para-Commander (PC). The Para-Commander had cutouts at the rear and sides that enabled it to be towed into the air and steered, leading to parasailing/parascending.

Author Walter Neumark wrote Operating Procedures for Ascending Parachutes, and in 1973 he and a group of enthusiasts with a passion for tow-launching PCs and ram-air parachutes broke away from the British Parachute Association to form the British Association of Parascending Clubs (which later became the British Hang Gliding and Paragliding Association). In 1997, Neumark was awarded the Gold Medal of the Royal Aero Club of the UK. Authors Patrick Gilligan (Canada) and Bertrand Dubuis (Switzerland) wrote the first flight manual, The Paragliding Manual in 1985, coining the word paragliding.

These developments were combined in June 1978 by three friends, Jean-Claude Btemps, Andr Bohn and Grard Bosson, from Mieussy, Haute-Savoie, France. After inspiration from an article on slope soaring in the Parachute Manual magazine by parachutist and publisher Dan Poynter,[7] they calculated that on a suitable slope, a "square" ram-air parachute could be inflated by running down the slope; Btemps launched from Pointe du Pertuiset, Mieussy, and flew 100 m. Bohn followed him and glided down to the football pitch in the valley 1000 metres below.[8] Parapente (pente being French for 'slope') was born.

From the 1980s, equipment has continued to improve, and the number of paragliding pilots and established sites has continued to increase. The first (unofficial) Paragliding World Championship was held in Verbier, Switzerland, in 1987,[9] though the first officially sanctioned FAI World Paragliding Championship was held in Kssen, Austria, in 1989.[10]

The paraglider wing or canopy is usually what is known in engineering as a ram-air airfoil. Such wings comprise two layers of fabric that are connected to internal supporting material in such a way as to form a row of cells. By leaving most of the cells open only at the leading edge, incoming air keeps the wing inflated, thus maintaining its shape. When inflated, the wing's cross-section has the typical teardrop aerofoil shape. Modern paraglider wings are made of high-performance non-porous materials such as ripstop nylon.[note 1]

In most modern paragliders (from the 1990s onwards), some of the cells of the leading edge are closed to form a cleaner aerodynamic profile. Holes in the internal ribs allow a free flow of air from the open cells to these closed cells to inflate them, and also to the wingtips, which are also closed.[12] Almost all modern paragliders follow a sharknose design of the leading edge, by which the inflation opening is not at the front of the wing, but slightly backwards on the underside of the wing, and following a concave shape. This design, resembling the nose of a shark, increases wing stability and stall resistance.[13][14] In modern paragliders, semi-flexible rods made out of plastic or nitinol are used to give extra stability to the profile of the wing. In high-performance paragliders, these rods extend through most of the length of the upper wing.

The top of each line is attached to small fabric loops sewn into the structure of the wing, which are generally arranged in rows running span-wise (i.e., side to side). The row of lines nearest the front are known as the A lines, the next row back the B lines, and so on.[15] A typical wing will have A, B, C and D lines, but recently, there has been a tendency to reduce the rows of lines to three, or even two (and experimentally to one), to reduce drag.

Paraglider lines are usually made from UHMW polythene or aramid.[15] Although they look rather slender, these materials are strong and subject to load testing requirements. For example, a single 0.66 mm-diameter line (about the thinnest used) can have a breaking strength of 56 kgf (550 N).[16]

The glide ratio of paragliders ranges from 9.3 for recreational wings to about 11.3 for modern competition models,[17] reaching in some cases up to 13.[18] For comparison, a typical skydiving parachute will achieve about 3:1 glide. A hang glider ranges from 9.5 for recreational wings to about 16.5 for modern competition models. An idling (gliding) Cessna 152 light aircraft will achieve 9:1. Some sailplanes can achieve a glide ratio of up to 72:1.

For storage and carrying, the wing is usually folded into a stuffsack (bag), which can then be stowed in a large backpack along with the harness. Some modern harnesses include the ability to turn the harness inside out such that it becomes a backpack, saving weight and space.

Paragliders are unique among human-carrying aircraft in being easily portable. The complete equipment packs into a rucksack and can be carried easily on the pilot's back, in a car, or on public transport.[15] In comparison with other air sports, this substantially simplifies travel to a suitable takeoff spot, the selection of a landing place and return travel.

Tandem paragliders, designed to carry the pilot and one passenger, are larger but otherwise similar. They usually fly faster with higher trim speeds, are more resistant to collapse, and have a slightly higher sink rate compared to solo paragliders.

The pilot is loosely and comfortably buckled into a harness, which offers support in both the standing and sitting positions. Most harnesses have protectors made out of foam or other materials underneath the seat and behind the back to reduce the impact on failed launches or landings. Modern harnesses are designed to be as comfortable as a lounge chair in the sitting or reclining position. Many harnesses even have an adjustable lumbar support. A reserve parachute is also typically connected to a paragliding harness.

Harnesses have a substantial influence on the flying characteristics; for instance, acro harnesses lead to more agile handling, which is desirable for flying acrobatics, but may be unsuitable for beginners or XC pilots looking for more stability in flight. While pod harnesses offer more stability and aerodynamic properties, they increase the risk of riser twist, and are hence not suitable for beginners. The standard harness is an open harness, which features a sitting, slightly reclined body position.

The main purpose of a variometer is in helping a pilot find and stay in the "core" of a thermal to maximise height gain and, conversely, to indicate when a pilot is in sinking air and needs to find rising air.Humans can sense the acceleration when they first hit a thermal, but cannot detect the difference between constant rising air and constant sinking air. Modern variometers are capable of detecting rates of climb or sink of 1 cm per second.A variometer indicates climb rate (or sink-rate) with short audio signals (beeps, which increase in pitch and tempo during ascent, and a droning sound, which gets deeper as the rate of descent increases) and/or a visual display. It also shows altitude: either above takeoff, above sea level, or (at higher altitudes) flight level.

GNSS is a necessary accessory when flying competitions, where it has to be demonstrated that way-points have been correctly passed.The recorded GNSS track of a flight can be used to analyze flying technique or can be shared with other pilots. GNSS is also used 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.GNSS is integrated with some models of variometer. This is not only more convenient, but also allows for a three-dimensional record of the flight. The flight track can be used as proof for record claims, replacing the old method of photo documentation.

Increasingly, smart phones are used as the primary means of navigation and flight logging, with several applications available to assist in air navigation. They are also used to co-ordinate tasks in competitive paragliding and facilitate retrieval of pilots returning to their point of launch. External variometers are typically used to assist in accurate altitude information.

Paraglider ground handling, also known as kiting, is the practice of handling the paraglider on land. The primary purpose of ground handling is to practice the skills necessary for launching and landing. However, ground handling could be considered a fun and challenging sport in and of itself.

Ground handling is considered an essential part of most paragliding wing management training. It needs to be remembered that in any sort of stumble or tumble, the head is at risk and a helmet is therefore always advisable.

It is highly recommended that low hour pilots, ground-handling, should be wearing a formal harness with leg and waist straps firmly fitted and fastened. Since 2015 the standard harness has become an inflatable type. This forms a protective cushion when, during flight, air is forced through a check valve and retained in a chamber behind and under the pilot. In ground-handling practice the amount of air passing through the check valve may be very slight. In an accident where the pilot has been lifted and dumped while facing downwind, the protection offered by an inflatable harness is likely to be minimal. The old fashioned foam type of harness has a special value in that sort of situation.

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