Slope soaring
Slope soaring involves locations where horizontal winds are pushed upwards over a ridgeline, or slope. This creates a strong, steady, non-thermal updraft in which planes can glide. Slope planes tend to be stronger and heavier than other planes in the same size/shape class, both because they can afford to be due to the copious lift and because sections of the slope used for launch are rarely ideal for landing - they may be rocky and have little flat area available, leading to common rough landings. Slope soaring may be done with or without motor assist.
[edit] Hotliners
Sailplanes which specialize in slope soaring for speed or aerobatics, usually made of carbon fiber / fiberglass and without electric assist, are known as 'hotliners'.
Hotliner aerobatics are very different from powered flight aerobatics, taking the large glide ratios inherent to the sailplane design and using airfoils and materials with an extremely wide speed range to float through maneuvers working purely with gravitational potential energy and momentum.
Typically, hotliners are made with a very thick composite covered foam core, but designs which are intermediate between normal planes and hotliners because they are less rigid (dense foam) or more brittle (balsa & thinner composites, monokote), may be referred to as 'Warmliners'.
[edit] Dynamic Soaring
The compressed stream of high-speed air in the first several hundred meters above the slope stands in stark contrast to the stable, slower-moving air above and upwind of it. Slope soaring involves utilizing this natural updraft for gliding, but more specifically, dynamic soaring involves jumping in and out of the stream of high-speed air while changing direction but conserving momentum, in order to achieve speeds far in excess of the speed of either body of air. Because they are not limited by supersonic effects in propeller tips, dynamic soaring 'hotliners' have achieved far faster speeds than small propeller or EDF planes can commonly achieve in level flight.
Dynamic soaring speed attempts are notoriously hard to film due to the extreme speeds involved. Given those speeds, any crash will result in complete destruction of the aircraft.
