Ever wonder about how gliders get up in the air without an engine? There are three main ways to do so: Aerotow, Winch-Launching, and Self-Launching.
The aerotow starts with hooking up a rope to the tow hook on the nose of the glider. When the glider and towplane pilots are both ready to go another person raises the wing tip of the glider, levelling the wings and uses hand signals to tell the towpilot to begin the launch. The glider and towplane only have to accelerate a few feet before the wing runner can let go, and the aerotow is on its way. The glider and towplane fly in formation until the glider releases the tow rope at the desired launch height. Typically this is 2000 feet above the ground.
Winch launching requires about 4,000 feet of light-weight wire or composite cable. When the glider pilot is ready a wing runner levels the wings of the glider and signals the winch operator near the cable drum to start reeling in the cable. Quite quickly the glider is flying on its own and flying skywards at a 45 degree angle. The whole launch is often done in about two minutes when the cable is released by the glider. A small parachute is deployed when the cable is released that gently guides it to the ground. It is then stretched out to launch the next glider.
Self-launching is typically done with a small gasoline or electric engine, with the propeller mounted on a retractable boom. Yes, we did say that gliders are not propelled by engines. These self-launching gliders only use the engines for the launch. Once the glider has reached the desired launch height, the engine is stopped, and the boom is retracted inside the body of the aircraft. As it retracts, small doors close to complete the streamlining, and the glider is ready to soar. Should the need arise if lift cannot be found, the engine can be extended again in flight and restarted, to try again or go home.