Gliding

Gliding is a recreational activity and competitive air sport in which pilots fly unpowered aircraft called gliders or sailplanes, using naturally occurring currents of rising air to stay airborne. The word soaring is also used for the sport. As a sport it began in the 1920s, first aiming to lengthen flight duration and soon moving to cross-country flights away from the launch site. Better aerodynamics and weather understanding now allow longer distances at higher speeds, using ridge lift, thermals and lee waves, and experienced pilots can fly hundreds of kilometres, sometimes more than 1,000 kilometres, before returning to their home airfield. Some pilots race around pre-defined courses in gliding competitions, with local and national events in many countries and biennial World Gliding Championships. Competitors use speed-to-fly techniques, GPS navigation and water ballast. Aircraft are launched by powered aircraft or winches, and gliding clubs usually provide the facilities, training and safety standards.