Gliding is a challenging and enjoyable recreational activity and competitive air sport in which pilots fly unpowered aircraft known as gliders or sailplanes using naturally occurring currents of rising air in the atmosphere to remain airborne. The word soaring is also used for the sport.
Gliding as a sport began in the 1920s. Initially the objective was to increase the duration of flights but soon pilots attempted cross-country flights away from the place of launch. Improvements in aerodynamics and in the understanding of weather phenomena have allowed greater distances at higher average speeds. Long distances are now flown using any of the main sources of rising air – ridge lift, thermals and lee waves. When conditions are favourable, experienced pilots can now fly hundreds of kilometres before returning to their home airfields; occasionally flights of more than 1,000 kilometres are achieved.
Some competitive pilots fly in races around pre-defined courses. These gliding competitions test the pilots' abilities to make best use of local weather conditions, as well as their flying skills. Local and national competitions are organised in many countries, and there are biennial World Gliding Championships. Techniques to maximise a glider's speed around the day's task in a competition have been developed, including the optimum speed to fly, navigation using GPS and the carrying of water ballast. If the weather deteriorates pilots are sometimes unable to complete a cross-country flight. Consequently they may need to land elsewhere, perhaps in a field, but motorglider pilots can avoid this by starting an engine.
Powered-aircraft and winches are the two most common means of launching gliders. At Narrogin, we use a Piper Pawnee PA25 powered aircraft to tow the gliders to release height, when the tow rope is released by the glider pilot.