Last year's winning pilots averaged about 80 mph. Once the aircraft is launched in the sky, the trick is riding from cloud to cloud. Most sailplanes are hooked to the end of a 200-foot rope and launched by a regular powered airplane. Some sailplanes, however, do have an engine with which they can launch themselves. Once aloft, the motor is cut and pilots are on their own.
Thermals are gas stations in the sky.
Flight depends on thermals, not wind. It's the same principal by which hawks and eagles soar and glide. A thermal is defined as a column of warm rising air, caused by the uneven heating of the earth or sea by the sun. If we see the hawks circling, we know it's a good thermal. We share the sky.