Let me explain briefly… Gliding is flying an unpowered aircraft using the same air currents that birds use to fly. So you literally fly like a bird ! Using these invisible currents of air, known as ‘updraft’, you can soar to great heights and travel great distances at average speeds of over 100 miles per hour.
Gliders are designed to fly without an engine, thus they are very light and efficient thanks to their sleek design. In order for a glider to fly, it must generate lift to oppose its weight. But how do you generate lift without an engine ? Easy… You do it just like the birds… The pilot should locate a pocket of air that is rising faster than the glider is descending. This way the glider can gain altitude and increase its potential energy.
Rising air pockets are called updrafts. Updrafts can be formed in many different ways. One of them is the “Thermal”; The heat from the ground warms the surrounding air and that causes rising air pockets to form. These rising air pockets are called thermals. Birds are often seen circling inside a thermal to gain altitude without flapping their wings. Glider pilots do the exact same thing. Once they spot or feel a thermal, they start to circle the aircraft inside that hot air pocket to climb.
A typical Glider has a glide ratio of 30:1. This means that in smooth air a glider can travel forward 3000 meters while losing only 100 meter of altitude. Pretty efficient indeed.
Flying without an engine requires experience, skill, devotion and meticulous planning. In powered aircraft “weather” is often something to be avoided, but for glider pilots, it is the power under our wings. Reading and understanding the weather are equivalent to the power-pilot’s fuel tanks and engine.