Hang glider

The hang glider or delta wing is a Aéronef of Coasting flight, with rigid reinforcement. Its practice is an air sport framed, in France, by the French federation of Coasting flight mainly.

History

The hang glider is a flying equipment, adapting the Aile Rogallo to the concept invented in the Années 1890 by Otto Lilienthal.

At the end of the years 1950, the engineer Francis Rogallo works on a wing intended to equip the space capsules for the re-entry in the atmosphere. This wing must be light, collapsible, easy to implement, etc Its work lead to a wing in triangular flexible fabric. The voluminal shape of the fabric is given by the blast pressure. The first tests on Cerf-volant are conclusive, but the project is not adopted for the space capsules (one will prefer the traditional parachute gluteus).

Thereafter, one will think of using this wing to spring a height.

Basic the Rogallo wing has large defects, particularly that to lose its form in certain circumstances (the fabric is put flat). In this case, it does not carry any more, and it is the assured crash landing. The first evolution consisted in putting a mast above the wing, in order to always keep the fabric in-flight status thanks to stays.

In order to gain in performance, the modern hang gliders are equipped with a double-side wing, i.e. having, like the wings of planes, a suction face and a under-surface: slats, or members, are used to preserve the profile wing. In the years 1990, progress of the materials (metal alloys, composites, plastics and glass fiber or carbon) allowed the manufacture of hang gliders initially without mast nor stay, then with rigid wings.

The unreliability of the apparatuses and a little wild formation of the first years contributed to the many accidents and the initial bad reputation of the hang glider. Today, the apparatus is surer and vocational training.

These improvements of the reliability and the courses of formation, combined with an increasing mediatization, like the organization of events such as the Cut Icare in France, initially allowed a certain rise of the hang glider. This rise was then compromised by the development of a new type of aircraft: the Parapente. This last, felt like easier to use than the hang glider (storage, transport,…) marginalized the hang glider gradually in practice coasting flight. However, the hang glider preserves its specific qualities (better smoothness, higher speed of flight, horizontal position of the pilot to the manner of a bird, greater lifespan…) who allows him to continue to count in the whole world of very many practitioners.

Principle of flight

The principle is relatively simple: a wing in the shape of delta, is self-stabilizing when it flies. “Pendular” piloting is done with little effort. The pilot is lengthened the head with the wind in a profiled integral harness, fixed on the solid skeleton of the wing, at the anchor point in the middle of the sail. The “trapezoid” with its two amounts and its bar of control makes it possible to the pilot by the effort of his arms to shift on the sides and of before behind moving the center of gravity compared to the center of Portance of the delta wing what generates a light twist of the wings, sufficient to induce a turn or an acceleration.

On the “rigid” evolution, piloting is very different and is done without effort using ailerons integrated into the wing.

Whatever the type of wing used, in accordance with the principles of the Coasting flight, the Takeoff and the Atterrissage are done with foot, while carrying this light aircraft.

Takeoff more running with an hang glider is carried out since a point located in height, simple a Colline being able to be enough. Certain sites are equipped with a slope facilitating this operation. The hang glider can be also practiced in Plaine, takeoff being then carried out thanks to a especially designed Treuil.

Evolution of the wings

Since 1970, the delta wings have remarkably advanced, passing from the Rogallo wing to the rigid wing. In spite of the small number of deltists, it is maintained some manufacturers who propose increasingly tempting machines. Two types of machines coexist since end of the year 90:

the machines with structures aluminum, known as “flexible” hang glider, they result from the Rogallo wing but with a definitely higher lengthening (env.8), the chechmate disappeared and the airfoils are worked definitely more, therefore powerful. (smoothness 15, rate of fall 0,9m/s, speed max 100 km/h).
the machines with structures carbon, known as “rigid” hang glider, they consist of 2 principal beams with profile in “D” for the leading edge, the trailing edge being built by Carbon slats always. The whole is wrapped of a fine fabric. (smoothness ~20, rate of fall 0,9m/s, speed max 120 km/h, lengthening approx. 11).

The hang gliders of training are of type “flexible” with fabric a less tended, simple surface, and always with a chechmate.

Whereas the market of occasion makes it possible to be equipped with few expenses, the new machine of season of a candidate comes very close to the 7000 euros for flexible, and 13000 Euros for rigid.

Hang glider: a sport at the risk?

In France, the study 2005 of the commission safety of the FFVL concludes: the statistics death of 0.26 per thousand (0,00026) makes it possible to confirm that the coasting flight remains well a sport " with risques" and that the fatal risk is completely comparable with that of other sports " with risques" and/or of full nature. .

It is necessary however to take these figures with prudence for several reasons. The principal one is that the figures relate to all the coasting flight activity (thus including the parapente), while at the same time the hang glider is minority in this practice. The FFVL counts less than 1000 bachelors in France stating to practice the hang glider, which makes a sample too much small of it to provide a rate to the ten thousandths, while at the same time the number of annual fatal accidents in the hang glider fluctuates between zero and a few units. To only base itself on one year old figures is thus not really significant in this context since one year without death in the hang glider would not make it possible to say only " the hang glider is not a sport with risque".

Competitions

The competitions at the beginning were in connection with the poor performances of the apparatus: better smoothness, which allowed an emulation of the various manufacturers, or of single precision of landing. With the increasingly powerful wings, the principle rests on the realization, starting from a common takeoff, of a circuit defined by the imposed overflight of beacons. Those are defined by coordinated what implies a suitable instrumentation of flight; formerly locatable points on the ground were to be photographed under a certain angle. The courses defined from day to day according to the weather conditions by a director of test can reach the 200km. Each country has its national championship, a European championship is organized every 2 years and a championship of the world every 4 years, bringing together the national teams of the competitor countries. More than 100 pilots can contribute.

There exists a classification and sometimes competitions separated between the category of “flexible” (the traditional hang glider) and its “rigid” evolution for reasons of different performance.

Records

Manfred Rühmer, pilot Austrian several times world champion, is recordman of distance with 700 km covered in 10:00.

Many records were established in France, through the Alps, in particular of the flights of more than 300 km. (Antoine Boisselier, in a white-Switzerland Worthy-Grenoble-Annecy-Mount)

Speeds of flight at the time of these records border the 70km/h of average.

External bonds

National committee of the hang glider
Bible of the wings of hang glider
Historical deltaplane.info
World records
of the hang glider
Championship of the World of Coasting flight Lifting

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