Paragliding

Rush4 entering the catabatic wind (Chile).

The paraglider (from the French parapente, an acronym for parachute, parachute, and pente, slope) is a fixed-wing aerodyne considered a sport born at the end of the 20th century by the inventiveness of mountaineers who wanted to fly down with a parachute from the peaks they had ascended.

The wing, and sometimes the whole team, is called by the same name, paragliding. The technical definition is: ultralight flexible glider. Glider because it does not have an engine and flexible because there are no rigid parts that make up the wing, so it can be transported in the trunk of a car. The weight of all the equipment is usually around 10-20 kg, although there are mountain equipment that weighs less than 5 kg. The pilot and occasionally the passenger (for which a two-seater paraglider is used whose equipment can reach 30 kg) of paragliding will be equipped with the mandatory safety equipment, seat-harness, helmets, goggles and emergency parachute, and with various electronic instruments: variometer or altivario, GPS and radio equipment.

Description

A paraglider is an ultralight hovercraft, consisting of a wing with a non-rigid or soft structure called a sail or sail, made of synthetic fabric called Rip Stop whose weft has reinforcing threads that stop eventual tears. That acquires its profile or shape by the pressures that the air that enters through the mouths located on the leading or front edge exerts inside the cells or drawers. This is attached to the harness or chair by means of thin ropes of synthetic material (kevlar, dyneema, etc.) called suspenses or cords, which end their branching in some maillons that join them to a set of 2, 3, or 4 straps per side called BANDS (which are differentiated from each other as A, B, C, etc. starting with the front ones), these in turn are unified in two anchors (left and right) that are finally attached to the harness by means of a pair of carabiners As far as its basic operation is concerned, it takes off and lands on the pilot's legs and is controlled by means of a pair of controls (left and right), called brakes, which act by folding down the trailing edge of the wing, modifying in this way the aerodynamic profile of the same. To the control of the controls, the effect produced by modifying the wing loading of the wing in different areas of the wing can be added, this is by tilting the body to the sides.

Being a type of flexible wing, turbulence and especially shear can produce folds that deform the wing profile, thus losing part of its lift capacity and entering into different flight configurations: asymmetric or frontal folds, autorotation, auger etc If the incident occurs at a sufficient height, normally it will be possible to return to the natural flight configuration, but if this is not the case, the last resort is to use a very basic parachute for an emergency that rarely occurs.

A part of the training of a paraglider pilot is precisely to learn to control the paraglider during incidents in flight. This type of course is called SIV (Simulation of Incidents in Flight). In this course the pilot will learn to master the paraglider in the event of an incident, to perform useful maneuvers (spins, stalls) and to use the emergency parachute correctly. These types of courses are carried out above the water, with the presence of a rescue boat for greater safety in case of having to use the emergency parachute.

The maximum and minimum range of relative speeds for an intermediate paraglider model is: Maximum speed: 50 kilometers/hour. Minimum speed: 24 km/h. A competition paraglider can exceed 60 km/h and a glide ratio, or "fineness" of 11:1, that is to say, that for every 11 relative meters of air that advances, one descends (we must think that being in the air, the speed in this case will always be relative to the strength and direction of the wind, and not to be confused with GPS actual ground speed). All paragliders are in permanent descent and the autonomy to move in the air is simply the altitude at which they are, since they depend on air currents to gain height.

It is about being able to take off, fly and land with a flexible wing by the pilot's own means, that is, on foot. The ideal would be from a not very steep slope and facing a moderate wind of about 10-20 km/h, or even less if you intend to fly near the coast, since the air will have a higher density there due to atmospheric pressures and higher relative humidities. Then the pilot will sit comfortably in a chair or harness, attached to the lines of suspension by means of two carabiners.

The flight pattern is pendulum, which means that the pilot has direct control in only two of the three planes of flight: roll (with the weight of the pilot and the brakes) and pitch (with both brakes simultaneously and with The accelerator); yaw, therefore, being tailless, is out of the pilot's control.

Paraglier taking off with traction (Torno)

Another possible way for a paraglider to take off is to do it with a fixed traction winch or a mechanical unwinder installed in a vehicle or boat controlled by an operator. This is hooked on the harness by means of a quick release system, which the pilot will activate when the turner tells him to. It is a typical type of plains flight (especially in deserts, where the highest altitudes are reached) and here the duration of the flight depends on the pilot's ability to get as high as possible and then encounter rising air currents.

We can also see paramotors when the same wing is attached to a chair or harness with a gasoline or electric combustion engine and a two or three-blade propeller that propels the entire system at the pilot's will. Although the wings are the same or very similar, the sensations, weather conditions, flight techniques with or without a motor and environmental impact differ greatly between them, since while the paramotor enjoys autonomy to move through the air, the paraglider does not.

A glider in the air

The science of gliding and, consequently, paragliding is based on thermal currents and dynamic currents. The first are produced when a mass of air is heated by conduction, that is, by the contact of the air on a ground heated by the sun's rays. Said mass of air expands when its temperature rises and is lighter than the surrounding air, so once the resistance created by the viscosity of the air is overcome, it begins to rise in the form of bubbles or as more or less cyclical vertical currents.. This rise of hot air, called thermal, is the main engine used by all glider aircraft. In the second case, the ascending direction of the wind is used when overcoming some obstacle, a technique almost always reserved for some coastal birds and paragliding. In thermal flight, the skill lies in centering the ascending channel well in order to obtain maximum rate of climb while losing as little height as possible in the turn. But before that we must find those thermal currents; They can be adrift from the most arid areas of the land, on the slopes with the most incidence of sun rays, in the lee of obstacles, etc. In addition, convection or cumulus clouds mark them, just as lenticular clouds show high wind speeds, you can also read the direction of the wind in the shape of the clouds.

Flight Types

One of the most coveted disciplines within paragliding is the cross country flight or distance flight, which implies, unlike the local flight, where after taking off you remain within the area until the moment you land on landing officer authorized to do so, leave, prior to planning, although generally under some uncertainty, to travel long distances, for which alternative landings will have to be sought in case of losing too much height.

Paragliding in Spain.

The thermodynamic flight is nothing more than taking advantage of the convergence of breezes of different orientation that produces an elongated ascending zone and generally crowned by convection or cumulus clouds. This convergence can be derived by the existing meteorological wind in higher layers of the atmosphere and they are authentic free flight highways. Distances of 550 kilometers in a straight line have been exceeded thanks to this phenomenon. (see also thermal flight)

Beyond the way the lifts are combined, a true cross country flight must necessarily involve taking altitude in a thermal current or zone of lifts, to then make the transition to the next one and so on. Bearing in mind that every glider always glides downwards with respect to the air, the balance between the height gain and the length of the transition to the next lift zone play a fundamental role to successfully carry out a long flight, for which, in addition to the traditional security elements are added a spot-type beacon, water, food, appropriate clothing to walk for hours or even days, bivouac equipment, flashlight, etc.; however, one of the most important aspects is planning based on experience, and weather conditions

Restitution is a thermal flight that occurs at sunset when large masses, especially rocks and arid lands, gradually return to the atmosphere the heat stored during hot days and with little wind, generating gentle lifts but with enormous dimensions. This action is increased in the valleys by fresh currents, or katabatic winds, which come down along the slopes after sunset.

Dynamic flight is carried out moving in front of an obstacle facing the wind, as a surfer would slide down a wave, since this wind, when going up the slopes, provides a supporting air mass. The mountain wave has the same effect, with the exception of being produced by strong meteorological winds, which, when rising and descending due to orographic accidents, produce ups and downs, as well as very turbulent areas, also called "rotors".

Pillars for paragliding

The responsible practice of this sport necessarily implies having knowledge of the five pillars that are mentioned below and will be studied by the students in the courses (initiation, progression, improvement, two-seater or instructor).

Meteorology

Given the fragility that this type of aircraft presents in the air, something really essential to reduce risks is to make an accurate reading of the current and future weather, since it could exceed the capabilities of both the team and the pilot. Depending on the type of flight (dynamic or thermal), the force of the wind and its direction play an essential role when choosing the day and time to practice this exciting sport. In principle it could be said that to fly thermals the best thing is the absence or scarcity of wind and to fly dynamics a speed that does not exceed the speed of the paraglider without using the accelerator.

The atmosphere is the layer of air that surrounds the earth and its thickness is about 500 km. Inside it, the air is organized into various superimposed layers with different characteristics. These differences, especially in temperature and pressure, are precisely what keep each layer well differentiated from the others. The atmosphere does not tolerate large differences between the air masses inside it, so it continually corrects the imbalances that occur by acting as a true regulator of temperature and pressure. For this, the air always circulates from the areas of higher pressure to those of less, as well as from the colder areas to the warmer ones, producing convective (or vertical) and advective (or horizontal) air movements.

Lift marked by a thundercloud or cumulonimbus cloud is so great that it can overwhelm the aircraft and constitute a danger to the flight, both due to the enormous altitude to which they reach (sometimes 10,000 meters), due to the disorientation suffered by the pilot due to zero visibility, as well as due to the turbulence that may exist within it.

In many countries this activity is not regulated, and the use of defective equipment, not having safety accessories or carrying out this activity without a prior instruction course, could cause accidents that would be avoided if the sport were taken with more responsibility. Good training, a bit of good sense and a good team are the bases for this sport to be safe.

Regulations

Just as in the transit of any other vehicle, there are rules of coexistence in the air. This is important in terms of the safety factor since having pre-established agreements allows you to avoid incidents. On the other hand, the different modalities of competition, XC, ACRO, precision, etc. are also regulated.

Materials

Refers to the equipment and its periodic review, since although on the one hand the equipment is relatively light compared to other aircraft, the aging and deterioration of the material is quite fast, so periodic reviews are essential since it depends of it the safety of the flight. For this, different tests are carried out: fabric porosity, breaking load point of one of the main lines and trimming of the line system.