Gliding

Gliding is when an object or animal goes through the air without active flight. All gliders use an aerofoil to slow their rate of descent. Glider planes have wings, and gliding animals have membranes which they stretch out. By using rising air they can prolong their stay in the air. The word 'soaring' describes this, and is also used for the sport of gliding. 

Air will rise if it is heated by the ground or if it is deflected by mountains. Improvements in aerodynamics, in instruments and in the understanding of the weather have allowed flights over great distances at high speeds. The world record distance is now over 3000 km.

 Animals 
Many birds are good at gliding some Seabirds like the great frigatebird can fly for serval weeks without stopping. They evolved to do this because they needed to use less energy. Some examples of birds that can glide are:

 Albatross
 Condor
 Eagle
 Stork
 Frigatebird

They use the same types of lift as man-made gliders.

 Glider airplanes 
Main article: Glider

 History 
The development of the Glider started after World War I because the Weimar Republic (the name for Germany from 1918-1933) were not allowed to make airplanes with enginesHistory of gliding and soaring. Soaring society of America. so instead they made gliders. In 1936 Gliding was demonstrated (shown off) at the Summer Olympics in Germany. 

Gliders were used to move troops and equipment in World War II. The countries that had them were The United States, The United Kingdom, and Germany.  However unlike normal Gliders for the most part these planes could not use rising air to stay up in the sky.

Gliders were also used in several Air forces as training aids and in their cadet programs.

 References 

Category:Aviation
Category:Animal locomotion