The glider is the earliest man-made aircraft that can fly in the sky. It has a variety of shapes, mainly fixed-wing gliders and suspended wing gliders.
The glider has no power unit. It is carried by a glider athlete running on a sloping hillside and pushed into the air, or taken off by a winch, car or aircraft. The modern glider is equipped with a small auxiliary engine, which can take off and take off on its own. After the altitude, turn off the engine gliding flight.
When the glider is flying in the air, if there is no updraft, relying on the forward component of its own gravity as the flight power, this highly submerged unpowered down flight is called gliding. The glider uses the updraft formed by the ground or the valley to fly or rise, called soaring. The ratio of the distance between the glider flying forward and the sinking height is the gliding ratio, which is commonly used to measure the performance of the glider. The highest gliding ratio of modern advanced gliders has exceeded 50.