In general, the best weather conditions for gliding are bright and not too windy. Weather allowing, clubs offer training and fly throughout the year, with the primary cross country gliding season spanning from May to mid-September. Training flights are also available any other time of year, although visibility may be limited due to snow or rain. The choice of aircraft depends on how long you can stay in one place while flying. There are two types of glider: sailplane and winged keelboat. A sailplane has a large surface area made of cloth or plastic that is stretched between wooden ribs. It usually has two sets of wings, one set attached to the body at the front and one set at the rear. The pilot sits behind and slightly to the nose of the glider, which is powered by a motor mounted in the tail. A winged keelboat is very similar to a sailplane but has a metal frame instead of ribs for its wing structure. Its keel provides stability in flight and helps it land on water rather than crash into it. Sailplanes tend to be faster and have longer range than winged keelboats. They are more difficult to handle because there is less weight behind them so they require a stronger pilot. However, sailplanes are more expensive to buy and maintain.