This historic German educational film shows flights of sailplanes or gliders. After World War I many gliders were built for sporting purposes in Germany, because of post-WWI regulations forbidding the construction and flight of motorized planes. As a result the country's aircraft enthusiasts often turned to gliders and were actively encouraged by the German government, particularly at flying sites suited to gliding flight like the Wasserkuppe.
A glider or sailplane is a type of glider aircraft used in the sport of gliding. It has rigid wings and an undercarriage. Some gliders, known as motor gliders, are also used for gliding and soaring, but have engines which can be used for extending a flight and, for some types, for take-off. Aircraft such as hang gliders and paragliders are foot-launched and so are described in separate articles, though their differences from sailplanes are covered below. Glider aircraft that are used for purposes other than recreation, for example military gliders, do not soar.
Sports gliders benefit from creating the least drag for any given amount of lift, and this is best achieved with long, thin wings and a fully faired narrow cockpit. Aircraft with these features are able to climb efficiently in rising air and can glide long distances at high speed with a minimum loss of height in between.
Early gliders had no cockpit and the pilot sat on a small seat located just ahead of the wing. These were known as "primary gliders" and they were usually launched from the tops of hills, though they are also capable of short hops across the ground while being towed behind a vehicle. To enable gliders to soar more effectively than primary gliders, the designs minimized drag. Gliders now have very smooth, narrow fuselages and very long, narrow wings with a high aspect ratio and winglets.
The early gliders were made mainly of wood with metal fastenings, stays and control cables. Later fuselages made of fabric-covered steel tube were married to wood and fabric wings for lightness and strength.