Half-pipe

A half-pipe is a structure used in gravity extreme sports such as skateboarding, snowboarding, skiing, freestyle BMX, skating, and scooter riding.

The structure resembles a cross-section of a swimming pool, essentially two concave ramps (or quarter-pipes), topped by copings and decks, facing each other across a flat transition, also known as a tranny.

A skilled athlete can perform in a half-pipe for an extended period of time by pumping to attain extreme speeds with relatively little effort.

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.

The character of a half-pipe depends on the relationship between four attributes: most importantly, the transition radius and the height, and less so, the degree of flat bottom and width.

[4] On half-pipes which are less than vertical, the height, typically between 50% and 75% of the radius, profoundly affects the ride up to and from the lip, and the speed at which tricks must be executed.

Smaller transitions that maintain the steepness of their larger counterparts are commonly found in pools made for skating and in custom mini ramps.

Frame and support for skateboard, BMX, and vert skating half-pipes frequently consist of a 2×6×8" lumber (actual 38 × 140 × 184 mm) framework sheathed in plywood finished with sheets of masonite or Skatelite.

Sometimes a section of the platform is cut away to form a roll-in and a channel to allow skaters to commence a ride without dropping in and perform tricks over the gap.

[6] One current method of half-pipe cutting is by use of a Zaugg Pipe Monster, which uses five snow-cutting edges to create an elliptical shape that is purportedly safer and allows the rider to gain more speed.

[9] He set the record at the FIS Freestyle Ski and Snowboarding World Championships in 2015, when he achieved a height of 8.04 meters (26ft, 3in) above a 22-ft superpipe.