Most gliders, also known as sailplanes, cannot take off by themselves. They are designed to fly using the natural forces of the atmosphere, such as thermal updrafts, to stay aloft, but they need an external power source to reach flying altitude. Gliders are launched into the air by being towed behind a powered aircraft or using a winch launch. These methods provide the necessary initial energy and lift to get the glider in the air, so it can start flying on its own.
However there are some types of gliders that are equipped with engines, known as motor gliders and self launching gliders. These aircraft have a small engine that can be used to power the propeller for takeoff, and to maintain altitude or make a powered climb after takeoff. Once the glider reaches a sufficient altitude, the engine is shut off and the aircraft glides as a traditional glider. This allows the pilot to take off under his own power and eliminates the need for a towplane or winch launch.
