Soaring is a manner of flying wherewith glider pilots once launched, using upward moving air currents called “lift”, maintain and even increase altitude during their flights using no outside energy other than this atmospheric “lift” for power.

Soaring can be done for fun, as a hobby, and also competitively in organized soaring contests. Soaring objectives beyond the joy and feeling of freedom it procures, include : flying the longest possible distance with either a fixed destination or circuit, or a free circuit for the longest distance possible, or again flying for the longest distance within a specified time limit.

THE HISTORY OF SOARING

The history of soaring starts with the history of heavier-than-air flight. The first manned winged flight in history was accomplished by Guillaume Resnier at Angouleme in France in the early 1800s, followed by the soaring pioneer Otto Lilienthal making gliding flights between 1891 and 1896 near Berlin in Germany. The Wright brothers in the early 1900s are recognized for having made the first gliding then sustained flight with a controllable machine incorporating a launching principle.

Unpowered sustained flight was developed essentially in Germany in the period between the first and second world wars when Germany was forbidden to develop powered aircraft. German gliding aviators discovered and developed the various methods of using air currents (especially upward moving air currents) to fly farther and for longer flight-times. This culture has spread around the world, however German know-how and design expertise for gliders remains the worldwide reference.

SOARING BASICS

Soaring is defined as flying in air masses which have higher upward movement speed than the sink rate of the glider, thus increasing the glider’s potential energy. To accomplish this accumulation of potential energy, gliders will adopt a circular trajectory with the objective of staying within the upward-moving air masses (spiraling). The objective is to reach the maximum altitude for each ascendency. Altitude thus becomes the glider’s “fuel”. One could say that the glider fills its tank at each ascendency. Neophyte pilots will do this every 7 to 8 km or so up to 25 km, and much more for experienced pilots.

The different types of upward moving air masses used by glider pilots generating lift :

• Thermal lift which is the consequence of the uneven heating of the ground surface by the sun, heating the air in turn, and producing “columns” of rising “hotter” air (thermal lift) which a glider can use to gain altitude by climbing to the base of the cloud (cumulus) produced by this rising hot air. This phenomenon occurs from spring to early autumn;

• Dynamic lift which is produced by winds encountering mountain ridges and being forced upwards at a rate depending on wind speed and ridge shape.  When the ridge is exposed to the sun, heating occurs, and thermal lift will also be produced.  Gliders may exploit this combined lift and climb to up to 700m above the ridge line.

• Wave lift : when wind and mountain conditions are perfectly aligned, this situation can result in soaring altitude gains up to and beyond 10 000m thanks to lee waves. Lenticular-shaped clouds stacked like plates or floating individually high above the mountains are a sign of lee wave activity.  Soaring in the wave is a bit like surfing.

Generally speaking, glider flights will last from a few hours, up to 10 hours, with distances covered of up to 1000km.

LAUNCHING

Launching a glider is accomplished either by means of a tow plane called a “tug” which pulls the glider up in the air during the takeoff phase, and then tows the glider to an appropriate release point where there is adequate lift, or, by swiftly winching the glider up to a height of 300 to 500m above the airfield with a powerful winch in the manner of a person running to launch a kite.

Self-launching motorized gliders take off and climb to soaring height using a fixed or retractable motor.