Paradigling

Paragliding is the recreational and competitive adventure sport of flying paragliders: lightweight, free-flying, foot-launched glider aircraft with no rigid primary structure. The pilot sits in a harness suspended below a fabric wing comprising a large number of interconnected baffled cells. 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, paragliders flight can last many hours and cover many hundreds of kilometers, though flights of one to two hours and covering some tens of kilometers are more the norm. By skilful exploitation of sources of lift, the pilot may gain height, often climbing to altitudes of a few thousand meters.
Related activities

Paragliding is related to the following activities: Hang gliding is a close cousin, and hang-glider and paraglider launches are often found in proximity to one another. Despite the considerable difference in equipment, the two activities offer similar pleasures, and some pilots are involved in both sports.

Powered paragliding is the flying of paragliders with a small engine attached. Speed riding, or speed flying, is the separate sport of flying paragliders of a reduced size. These wings have increased speed, though they are not normally capable of soaring flight. The sport involves taking off on skis or on foot and swooping rapidly down in close proximity to a slope, even periodically touching it if skis are used. These smaller wings are also sometimes used where wind speeds are too high for a full-sized paraglider, although this is invariably at coastal sites where the wind is laminar and not subject to as much mechanical turbulence as inland sites.
Takeoff from a ramp, Tegelberg, Schwangau, Germany
Tandem Paragliding at Solang Valley, Manali, Himachal Pradesh, India
Paragliding over Jounieh Bay, Lebanon

Paragliding can be of local importance as a commercial activity. Paid accompanied tandem flights are available in many mountainous regions, both in the winter and in the summer. In addition, there are many schools offering courses and guides who lead groups of more experienced pilots exploring an area. Finally, there are the manufacturers and the associated repair and after-sales services. Paraglider-like wings also find other uses, for example, in ship propulsion and wind energy exploitation, and are related to some forms of power kite. Kite skiing uses equipment similar to paragliding sails.

Equipment
Wing

The paraglider wing or canopy is usually what is known in aeronautical 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 polyester or nylon fabric.
In some modern paragliders (from the 1990s onwards), especially higher-performance wings, 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.
The pilot is supported underneath the wing by a network of suspension lines. These start with two sets of risers made of short (40 cm) lengths of strong webbing. Each set is attached to the harness by a carabiner, one on each side of the pilot, and each riser of a set is generally attached to lines from only one row of its side of wing. At the end of each riser of the set, there is a small delta maillon with a number (2-5) of lines attached, forming a fan. These are typically 4–5 metres long, with the end attached to 2−4 further lines of around 2 m, which are again joined to a group of smaller, thinner lines. In some cases this is repeated for a fourth cascade.

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.[18] 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 Dyneema/Spectra or Kevlar/Aramid.[18] Although they look rather slender, these materials are immensely strong. For example, a single 0.66 mm-diameter line (about the thinnest used) can have a breaking strength of 56 kg.
Paraglider wings typically have an area of 20–35 square metres (220–380 sq ft) with a span of 8–12 metres (26–39 ft) and weigh 3–7 kilograms (6.6–15.4 lb). Combined weight of wing, harness, reserve, instruments, helmet, etc. is around 12–22 kilograms (26–49 lb).

The glide ratio of paragliders ranges from 9.3 for recreational wings to about 11.3 for modern competition models, reaching in some cases up to 13.[21] 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.

The speed range of paragliders is typically 20–75 kilometres per hour (12–47 mph), from stall speed to maximum speed. Beginner wings will be in the lower part of this range, high-performance wings in the upper part of the range.
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. For pilots who may not want the added weight or fuss of a backpack, some modern harnesses include the ability to turn the harness inside out such that it becomes a backpack.

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. 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.
Harness
A pilot with harness (light blue), performing a reverse launch

The pilot is loosely and comfortably buckled into a harness, which offers support in both the standing and sitting positions. Most harnesses have foam or airbag protectors 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 position. Many harnesses even have an adjustable "lumbar support". A reserve parachute is also typically connected to a paragliding harness.

Instruments

Most pilots use variometers, radios, and, increasingly, GPS units when flying.

Variometer

Main article: Variometer

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.

Radio

Radio communications are used in training, to communicate with other pilots, and to report where and when they intend to land. These radios normally operate on a range of frequencies in different countries—some authorised,[22][23] some illegal but tolerated locally. Some local authorities (e.g., flight clubs) offer periodic automated weather updates on these frequencies. In rare cases, pilots use radios to talk to airport control towers or air traffic controllers. Many pilots carry a cell phone so they can call for pickup should they land away from their intended point of destination.

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. The recorded GPS track of a flight can be used to analyze flying technique or can be shared with other pilots. GPS 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. GPS 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.

Control
Speedbar mechanism

Brakes: Controls held in each of the pilot’s hands connect to the trailing edge of the left and right sides of the wing. These controls are called "brakes" and provide the primary and most general means of control in a paraglider. The brakes are used to adjust speed, to steer (in addition to weight shift), and to flare (during landing).

Weight Shift: In addition to manipulating the brakes, a paraglider pilot must also lean in order to steer properly. Such weight shifting can also be used for more limited steering when brake use is unavailable, such as when under "big ears" (see below). More advanced control techniques may also involve weight shifting.

Speed Bar: A kind of foot control called the "speed bar" (also "accelerator") attaches to the paragliding harness and connects to the leading edge of the paraglider wing, usually through a system of at least two pulleys (see animation in margin). This control is used to increase speed and does so by decreasing the wing's angle of attack. This control is necessary because the brakes can only slow the wing from what is called "trim speed" (no brakes applied). The accelerator is needed to go faster than this.

More advanced means of control can be obtained by manipulating the paraglider's risers or lines directly. Most commonly, the lines connecting to the outermost points of the wing's leading edge can be used to induce the wingtips to fold under. The technique, known as "big ears", is used to increase rate of descent (see picture and the full description below). The risers connecting to the rear of the wing can also be manipulated for steering if the brakes have been severed or are otherwise unavailable. For ground-handling purposes, a direct manipulation of these lines can be more effective and offer more control than the brakes. The effect of sudden wind blasts can be countered by directly pulling on the risers and making the wing unflyable, thereby avoiding falls or unintentional takeoffs.
Fast descents

Problems with “getting down” can occur when the lift situation is very good or when the weather changes unexpectedly. There are three possibilities of rapidly reducing altitude in such situations, each of which has benefits and issues to be aware of. The "big ears" maneuver induces descent rates of 2.5 to 3.5 m/s, 4–6 m/s with additional speed bar. It is the most controllable of the techniques and the easiest for beginners to learn. The B-line stall induces descent rates of 6–10 m/s. It increases loading on parts of the wing (the pilot's weight is mostly on the B-lines, instead of spread across all the lines). Finally, a spiral dive offers the fastest rate of descent, at 7–25 m/s. It places greater loads on the wing than other techniques do and requires the highest level of skill from the pilot to execute safely.

Big ears

Paraglider in "Big Ears" manoeuvre

    Pulling on the outer A-lines during non-accelerated, normal flight folds the wing tips inwards, which substantially reduces the glide angle with only a small decrease in forward speed. As the effective wing area is reduced, the wing loading is increased, and it becomes more stable. However, the angle of attack is increased, and the craft is closer to stall speed, but this can be ameliorated by applying the speed bar, which also increases the descent rate. When the lines are released, the wing re-inflates. If necessary, a short pumping on the brakes helps reentering normal flight. Compared to the other techniques, with big ears, the wing still glides forward, which enables the pilot to leave an area of danger. Even landing this way is possible, e.g., if the pilot has to counter an updraft on a slope.

B-line stall
    In a B-line stall, the second set of risers from the leading-edge/front (the B-lines) are pulled down independently of the other risers, with the specific lines used to initiate a stall. This puts a spanwise crease in the wing, thereby separating the airflow from the upper surface of the wing. It dramatically reduces the lift produced by the canopy and thus induces a higher rate of descent. This can be a strenuous maneuver, because these B-lines have to be held in this position, and the tension of the wing puts an upwards force on these lines. The release of these lines has to be handled carefully not to provoke a too fast forward shooting of the wing, which the pilot then could fall into.

Spiral dive
    The spiral dive is the most rapid form of controlled fast descent; an aggressive spiral dive can achieve a sink rate of 25 m/s. This maneuver halts forward progress and brings the flier almost straight down. The pilot pulls the brakes on one side and shifts his weight onto that side to induce a sharp turn. The flight path then begins to resembles a corkscrew. After a specific downward speed is reached, the wing points directly to the ground. When the pilot reaches his desired height, he ends this maneuver by slowly releasing the inner brake, shifting his weight to the outer side and braking on this side. The release of the inner brake has to be handled carefully to end the spiral dive gently in a few turns. If done too fast, the wing translates the turning into a dangerous upward and pendular motion.
    Spiral dives put a strong G-force on the wing and glider and must be done carefully and skilfully. The G-forces involved can induce blackouts, and the rotation can produce disorientation. Some high-end gliders have what is called a "stable spiral problem".[24] After inducing a spiral and without further pilot input, some wings do not automatically return to normal flight and stay inside their spiral. Serious injury and fatal accidents did occur when pilots could not exit this maneuver and spiraled into the ground.

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