Common examples of gliders are sailplanes, hang gliders and paragliders. Any and all types of aircraft qualify, including airplanes, airships, balloons, gliders (sailplanes), helicopters, etc. Gliders and sailplanes that are used for the sport of gliding have high aerodynamic efficiency. When done in gliders (sailplanes), the sport is known as gliding and sometimes as soaring. The company was founded on the building and design of gliders and sailplanes. The airfield has a fleet of light aircraft and sailplanes. Types flown included Slingsby T.21B trainer, Grunau Baby, and various other pre-war German sailplanes. Manufacturers started to exploit this potential by offering tip extensions for their flapped sailplanes. Some sailplanes can achieve a glide ratio of up to 72&colon;1. The two most common methods of launching sailplanes are by aerotow and by winch. Schempp-Hirth manufactured 613 Ventus sailplanes. The term "sailplanes" is sometimes used. The Ventus-2a and 2b are 15 metre sailplanes. This opened in July 1939, when Slingsby Sailplanes Ltd was founded. In 1994 US distribution was transferred to "Mechta Sailplanes, LLC", which imported 18 Russia gliders.