Half-pipe
A half-pipe is a structure used in gravity extreme sports such as snowboarding, skateboarding, freestyle BMX and inline skating. The structure is usually wood, although sometimes the surface is made of another material. Appearance wise, it resembles a cross section of a swimming-pool, and in its most basic form, it consists of two concave ramps (or quarterpipes), topped by copings and decks, facing each other across a transition. Originally half-pipes were simply half sections of a large pipe. Since the 1980's half-pipes have had extended flat ground (the flat bottom) between the quarterpipes and the original style half-pipes have become curiosities. The flat ground gives the athlete time to regain balance after landing and more time to prepare for the next trick.
The attraction of the half-pipe lies in the fact that a skilled athlete can play on it for an extended period of time, using a technique called pumping, to attain extreme velocities, while expending relatively little effort. Large (high amplitude) half-pipes make possible many of the aerial tricks in BMX, in-line skating and skateboarding.
For winter sports such as freestyle skiing or snowboarding, a half-pipe can be dug out of the ground or created by piling snow up. The plane of the transition is oriented downhill at a slight grade to allow riders to use gravity to develop speed and facilitate drainage of melt. In the absence of snow, dug out half-pipes can be used by dirtboarders, motorcyclists, and mountain bikers.
Construction
Some ramps are constructed by spot-welding sheet metal to the frame, resulting in bumps and an uneven ride. Another common method is to screw sheets of plywood or masonite onto a wooden or steel frame. The surface might then be painted, or covered in sheet metal. Sometimes a section of the platform will be cut away to form a "roll-in". This allows skaters to commence a ride without dropping in, and perform tricks "over the gap". A roll-in is visible in the picture of Hulley's Ramp.
Recent developments in technology have produced a substance called "hARD" - which is smooth, easily shaped, durable and (importantly) dries quickly after rain. The ramps at Homebush (http://www.monsterpark.com.au) in New South Wales and West Beach in South Australia are constructed of hARD covering a steel frame.
External links
- Snowboarding on usolympicteam.com ... with news, bios, photos, more