Ski


Skis are runners, attached to the user's feet, designed to glide over snow. Typically employed in pairs, skis are attached to ski boots with ski bindings, with either a free, lockable, or partially secured heel. For climbing slopes, ski skins can be affixed to the base of each ski to prevent them from sliding backwards. Originally used as a means of travel over snow, skis have become specialized for recreational and competitive alpine and cross-country skiing.

Etymology and usage

The word ski comes from the Old Norse word skíð which means "cleft wood," "stick of wood," or "ski". In Old Norse common phrases describing skiing were fara á skíðum, renna and skríða á skíðum. In Norwegian this word is usually pronounced. In Swedish, another language evolved from Old Norse, the word is skidor. The modern Norwegian word ski and the Swedish word skid have largely retained the Old Norse meaning in words for split firewood, wood building materials and roundpole fence.
English and French use the original Norwegian spelling ski, and modify the pronunciation. Before 1920, English often called them skee and snow-shoe. In Italian, it is pronounced similarly to Norwegian, but the spelling is modified accordingly: sci. Portuguese and Spanish adapt the word to their linguistic rules: esqui and esquí. In German, spellings Ski and Schi are in use, both pronounced. In Dutch, the word is ski and the pronunciation was originally as in Norwegian, but since approximately the 1960s changed to. In Welsh the word is spelled sgi. Many languages make a verb form out of the noun, such as to ski in English, skier in French, esquiar in Spanish and Portuguese, sciare in Italian, skiën in Dutch, or Schi laufen or Schi fahren in German. Norwegian and Swedish do not form a verb from the noun.
Finnish has its own ancient words for skis and skiing: "ski" is suksi and "skiing" is hiihtää. The word suksi goes back to the Proto-Uralic period, with cognates such as Erzya soks, Mansi tåut and Nganasan tuta. The Sami also have their own words for "skis" and "skiing": for example, the Lule Sami word for "ski" is sabek and skis are called sabega. The Sami use cognates of čuoigat for the verb "to ski".

History

Skis appeared before the wheel, with the oldest wooden skis found in Russia, Sweden and Norway respectively.
These early skis were not designed for recreation or speed; their sole purpose was to keep the user on top of the snow, as when hunting or at war. Early skis were generally accompanied by a walking stick to help the user maintain balance.
Nordic ski technology was adapted during the early 20th century to enable skiers to turn at higher speeds. New ski and ski binding designs, coupled with the introduction of ski lifts to carry skiers up slopes, enabled the development of alpine skis. Meanwhile, advances in technology in the Nordic camp allowed for the development of special skis for skating and ski jumping.

Asymmetrical skis

This type of ski was used at least in northern Finland and Sweden until the 1930s. On one leg, the skier wore a long straight non-arching ski for sliding, and on the other a shorter ski for kicking. The bottom of the short ski was either plain or covered with animal skin to aid this use, while the long ski supporting the weight of the skier was treated with animal fat in similar manner to modern ski waxing. Early record of this type of skis survives in works of Olaus Magnus. He associates them to Sami people and gives Sami names of savek and golos for the plain and skinned short ski. Finnish names for these are lyly and kalhu for the long and short ski.

Single long ski

The seal hunters at the Gulf of Bothnia had developed a special long ski to sneak into shooting distance to the seals' breathing holes, though the ski was useful in moving in the packed ice in general and was made specially long, 3–4 meters, to protect against cracks in the ice. This is called skredstång in Swedish.

Modern skis

Around 1850, artisans in Telemark, Norway, invented the cambered ski. This ski arches up in the middle, under the binding, which distributes the skier's weight more evenly across the length of the ski. Earlier plank-style skis had to be thick enough not to bow downward and sink in the snow under the skier's weight. This new design made it possible to build a thinner lighter ski, that flexed more easily to absorb the shock of bumps, and that maneuvered and ran faster and more easily. The design also included a sidecut that narrowed the ski underfoot while the tip and tail remained wider. This enabled the ski to flex and turn more easily.
Skis traditionally were hand-carved out of a single piece of hardwood such as hickory, birch or ash. These woods were used because of their density and ability to handle speed and shock-resistance factors associated with ski racing. Because Europe's forests were dwindling, finding quality plank hardwood became difficult, which led to the invention of the laminated ski. Beginning in 1891, skimakers in Norway began laminating two or more layers of wood together to make lighter cross country running skis. These evolved into the multi-laminated high-performance skis of the mid-1930s.
A laminated ski is made of two types of wood glued together. A top layer of soft wood is glued to a thin layer under a surface of hardwood. This combination created skis which were much lighter and more maneuverable than the heavy hardwood skis made before. Although lighter and stronger, laminated skis did not wear well. The water-soluble glues used at the time failed; they warped and split along the glue edges frequently and rapidly. In 1922, a Norwegian skier, Thorbjorn Nordby, developed strong waterproof glue which stopped the problem of splitting, therefore developing a much tougher laminated ski. Research and design of laminated skis rapidly progressed. In 1933, a new design technology was introduced with an outer hardwood shell completely encasing an inner layer of lighter wood, successfully eliminating spontaneously splitting glue lines. This early design eventually evolved into an advanced laminating technique which is referred to today as single-shell casing technology.
In 1950, Howard Head introduced the Head Standard, constructed by sandwiching aluminium alloy around a plywood core. The design included steel edges and the exterior surfaces were made of phenol formaldehyde resin which could hold wax. This hugely successful ski was unique at the time, having been designed for the recreational market rather than for racing.
1962: a fibreglass ski, Kneissl's White Star, was used by Karl Schranz to win two gold medals at the FIS Alpine World Ski Championships. By the late '60s fibreglass had mostly replaced aluminum.
In 1974, Magne Myrmo became the last world champion using wooden skis.
In 1975, the torsion box ski construction design is patented. The patent is referenced by Kästle, Salomon, Rottefella, and Madshus. In 1993 Elan introduced the Elan SCX model, skis with a much wider tip and tail than waist. When tipped onto their edges, they bend into a curved shape and carve a turn. Cross-country techniques use different styles of turns; edging is not as important, and cross-country skis have little sidecut. For many years, alpine skis were shaped similarly to cross-country, simply shorter and wider, but the Elan SCX introduced a radial sidecut design that dramatically improved performance. Other companies quickly followed suit, one Austrian ski designer admitting, "It turns out that everything we thought we knew for forty years was wrong." Line Skis, the first free-ski focused ski company inspired the newschool freeskiing movement with its twin-tip ski boards in 1995. The first company to successfully market and mass-produce a twin-tip ski to ski switch was the Salomon Group, with its 1080 ski in 1998.

Geometry

Described in the direction of travel, the front of the ski, typically pointed or rounded, is the tip, the middle is the waist and the rear is the tail. Skis have four aspects that define their basic performance: length, width, sidecut and camber. Skis also differ in more minor ways to address certain niche roles. For instance, mogul skis are softer to absorb shocks, powder skis are wider to provide more float and rocker skis bent upwards at the tip and tail to make it easier to turn in deep and heavy snow.

Construction

Skis have evolved from being made of solid wood to using a variety of materials including carbon-Kevlar to make skis stronger, stiffer in twisting, lighter, and more durable. Ski manufacturing techniques allow skis to be made in one or a combination of three designs:

Laminate or sandwich

Laminated skis are built in layers. Materials such as fiberglass, steel, aluminum alloy, or plastic are layered and compressed above and below the core. Laminated construction is the most widely used manufacturing process in the ski industry today. The first successful laminate ski, and arguably the first modern ski was the Head Standard, introduced in 1950, which sandwiched aluminum alloy around a plywood core.

Torsion box

The Dynamic VR7 introduced a new construction method in which a smaller wooden core was wrapped in wet fibreglass, as opposed to pre-dried sheets of fibreglass being glued to the core. The result was a torsion box, which made the ski much stronger. The VR7, and its more famous follow-on VR17, was the first fibreglass ski that could be used for men's racing, and quickly took over that market. Over time, materials for both the core and torsion box have changed, with wood, various plastic foams, fibreglass, kevlar and carbon fiber all being used in different designs. Torsion box designs continue to dominate cross-country ski designs, but is less common for alpine and ski touring.