Gliding for Gold: The Physics of Winter Sports

3. Down the Slippery Slope

3 DOWN THE SLIPPERY SLOPE The bobsled (bobsleigh in Canada and Europe), the skeleton, and the luge all use the same track, though with di√erent starting points (as is illustrated in the plan of the Whistler Sliding Centre track in British Columbia, Canada, in fig. 3.1). These events di√er in the construction and weight of the sled, in the positions adopted by the sled rider(s), in the manner of starting o√, and in the techniques for steering and braking. Children of all ages sled for fun, of course. Most of us can remember being pushed down a snow-covered slope as a kid, on a sled of one type or another, and falling o√ at high speed. As adults, most of us sled surrogately —by proxy—preferring the comfort of a sofa in front of the TV (which is softer and doesn’t move so fast) as we watch highly trained athletes sled for fun and Olympic glory. If I were to be suddenly transported from my cozy sofa to a bobsled that is hurtling down the Cresta Run, I guess that sheer terror and exhilaration would crowd out any thoughts I might have about the science of sledding. Happily (or sadly) I
             Figure 3.1. Plan of the Whistler Sliding Centre track in British Columbia, Canada, site of the 2010 Winter Olympics. This track is up to 1,450 m (4,800 ft) long with a drop of 152 m (500 ft). T H E H I S T O RY O F C O M P E T I T I V E S L E D D I N G Sleds have been used recreationally, as well as for winter transport, for centuries in both Europe and North America. The sport of sledding, however , took off only in the late nineteenth century. Ex-pat Brits living in Switzerland took a liking to tobogganing, as they called it.* The winter resort of Davos gave its name to the first toboggan club, founded by J. A. Symonds in 1883. These well-to-do Englishmen built (or had built) a piste that ran from Davos to Klosters, a distance of 3.2 km (2 miles), and staged a contest involving 21 competitors from seven countries. A rival group of British expats based in nearby St. Moritz, encouraged by local entrepreneurs, constructed a rival track that came to be called the Cresta Run, which hosted its first competition in 1885. The Cresta Run was subsequently used in two Winter Olympics and is still in use today. This run is 1.2 km long (1,100 yd) and drops 157 m (514 ft) from start to finish.† In the same decade, sled design converged upon the three versions that we know today as bobsled, luge, and skeleton. The bobsledder sat in his sled; the luger sat on his sled, feet forward; the skeleton sledder lay prone on his sled, head forward. Bobsled was by far the most popular—a fact reflected in its early appearance in the Winter Olympics (beginning with the Chamonix games in 1924).‡ Luge has been an Olympic event since the Innsbruck games of 1964. Skeleton appeared at the St. Moritz games of 1928 and 1948 but has been a regular fixture of the Olympics only since 2002. Since 1923 these sledding events have been governed by the Fédération Internationale de Bobsleigh et de Toboganning (FIBT). *The word ‘‘toboggan’’ comes from an Amerindian word, whereas ‘‘sled’’ is of Germanic origin. Sleds have runners whereas toboggans are flat-bottomed. †For more detailed accounts of the origin of sledding events see, for example, the official IOC Web site (IOC 2010) and the St. Moritz Toboggan Club Web site (SMTC 2010). See also the articles on bobsledding, luge, skeleton sledding, and tobogganing in Encyclopedia Britannica (Britannica 1998) and Encarta (Microsoft 2005). ‡The Chamonix bobsled event was restricted to four-crew sleds. The two-crew bobsled appeared in 1932 at the St. Moritz games. Women’s bobsled (two-crew) did not appear until the Salt Lake City games in 2002. Though women had been encouraged to participate in the earliest sledding competitions in Davos and St. Moritz, they were barred from Olympic events from 1924 on. Perhaps this was because of the danger of this sport: overturning toboggans and toboggans that flew off the track had led to a number of serious injuries, and it was decided (by men, of course) that the fairer sex should not...