Gliding

Gliding is an airbourne sport, which is to sail or fly a glider to travel distances and raise no more help than the movement of air masses within the atmosphere.

History

There are numerous precedents for gliding. Otto Lilienthal is considered as the father of gliding. However, the true beginning of the game took place in Germany in 1920 with the first contest held in the Wasserkuppe gliders. Germany today remains the country where the most practitioners are and the most technical innovations occur.

The gliders were launched at the beginning of the sport in the 20s and 30s of the twentieth century, from the top of a slope aided by a system of rubber bands. The current rise of sailboats were towed by an airplane or a winch, which is a motor winding cable a hundred meters long that binds the vessel and this can drop to reach the desired height or vertical lathe. Upon reaching the desired height, the boat is unhooked from the cable that connects it to the airplane or the wheel and the flight is continued.

Technical

A boat is an aircraft without an engine, so that is always falling. An example: imagine a glider moving at 100 km/h and dropping a meter every second (1 m/s), but the pilot manages to stay in a rising stream of 5 m/s for 60 seconds: you will have gained 240 meters, and will have travelled over 1.6km.

The basic modalities are glider flight to thermal, wave and mountain slopes. On the flight to thermal, thermal currents produced by differential heating of the ground by the sun rise in the atmosphere, so that we stay with the glider to climb inside (usually turning into them). On the flight side, the wind that affects it is more or less perpendicular to the slope forcing it to rise.

If the slope is of sufficient size and the wind is well aligned with sufficient force, a sailboat located in an optimal position can fly resting on the wind without losing height. Finally, the mountain wave is a more complex phenomenon that occurs in the lee of mountain ranges on the incident a strong wind. This wind causes a wave phenomenon beyond the mountains, which under certain conditions can fly and reach great heights.

Regulations

Each country has its regulations to obtain a license or permit required to fly gliders. In addition, there are International diplomas recognized by the Federation Aeronautique Internationale for specific accomplishments. They begin today with the “C” of silver. To achieve them they require: 1) a straight-line distance of at least 50 km; 2) a height gain of 1000 meters and 3) a stay in the air of at least 5 hours.
The ancient titles A, B and C fell into disuse years ago when planners were capable of increasing performance. Other titles like C gold and diplomas (e.g. 1,000 km) are designed to recognize the most difficult flights.

Gliders

A simple measure of performance of a sailboat is the glide ratio. It is a measure of the maximum distance you can plan a sailing boat in top condition, from a given height. Thus, a glide ratio of 30:1 indicates that the boat could (theoretically) plan for 30km from an altitude of 1 kilometer (1,000 meters).

In real life there are many factors that influence the distance (wind, state of the atmosphere, cleaning the aircraft, to name a few). It is also not the only interesting feature of the face plane to consider their performance. However, it is easily used and widely recognized. The gliders were primitive wooden structures covered with fabric.

Technical advances since the beginning of the sport can be summarized into three stages: 1) wooden sailing ships gradually increasing the length and fineness of aerodynamic airfoils equipped with classics, culminating in the late 30s with sailing ships that had coefficients glide of approximately 30:1; 2)

In the 50’s they applied and developed laminar profiles progressively increasing the performance of sailboats gliding up rates of more than 40:1; 3) In the late 60’s construction was generalized in composite materials (fiberglass and plastic, and later carbon fiber and Kevlar), making flight surfaces cleaner aerodynamically, reaching the maximum glide ratios 60-70:1 of today’s most advanced sailboats.

A slightly more comprehensive measure is the “polar” of the sailboat, a curve that shows for each speed (with respect to the wind), the rate at which the boat drops (thus also indicates what the maximum glide ratio is). Now sailing ships have a fairly flat polar, i.e maintaining a low drop rate for high speed (200 km/h or higher).

The interest of observing the polar of a sailboat is because two different yachts can have a glide ratio of 30:1 at a speed of 90 km/h, but if one of them has a 25:1 ratio at 150 km/h, while another has a 20:1 ratio at this speed, we prefer the first, allowing us to move faster to lose less height, which is very useful, inter alia, to stay a short time within downdrafts.

Current status

At present the limits of gliding boundaries have expanded to unimaginable levels of a few years ago. An example: the German Klaus Ohlmann surpassed the barrier of 3,000km in 2003 (a single flight by day, without motor) with a free distance flight using three turning points in a Schempp-Hirth Nimbus 4DM. The flight took place starting from Chapelco, Argentina, and was mainly wave flying. It is considered the practical limit of current technology.