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A shaped, twin-tip alpine ski. This example has relatively little sidecut, and has a classic camber.

A ski is narrow strip of wood, plastic, metal or combination thereof worn underfoot to glide over snow. Substantially longer than wide and characteristically employed in pairs, skis are attached to boots with bindings, either with a free, lockable, or permanently secured heel.

Originally intended as an aid to travel over snow they are now mainly used recreationally in the sport of skiing.

Skis are also fitted to vehicles dedidcated to traveling over snow such as snowmobiles and snowcats.

History[link]

The Nordic ski technology was adapted during the early twentieth century to enable skiers to turn at higher speeds. New ski and binding designs, coupled with the introduction of ski lifts and snowcats to carry skiers up mountains, 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.

Design[link]

Ski nomenclature is relatively simple. Examining the ski from front to back along the direction of travel, the front of the ski (typically pointed or rounded) is the "tip", the middle is the "waist" and the rear (typically flat) is the "tail".

All skis have four basic measures that define their basic performance: length, width, sidecut and camber.

Length and width

The length and width of the ski define its total surface area, which provides some indication of the ski's "float", its ability to remain on top of the snow instead of sinking into it. The width by itself also has a strong relationship to the amount of drag as it moves though the snow. Efficiency in cross-country skiing depends on keeping the skis narrow to reduce drag, and thus requires them to be very long in order to produce the required amount of float. Alpine skis are generally not as concerned about drag, and tend to be shorter and wider.

Sidecut

Sidecut is the shape of the edge of the ski as viewed from the top or bottom. Alpine skis are wider at the tip and tail than they are at the waist; when rotated onto their edge, known as "edging", this causes the ski to bend into a curved shape and allows them to "carve" a turn. Cross-country techniques use different styles of turns; edging is not as important, and 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 radical sidecut design that dramatically improved performance. Other companies quickly followed suit, and it was realized in retrospect that "It turns out that everything we thought we knew for forty years was wrong."^[1] Since then, "shaped" skis have dominated alpine ski design.^[1]

Camber

Camber is the shape of the edge of the ski as viewed from one side or the other. Skis are traditionally designed so the tips and tails are naturally pressed down, and if laid on a flat surface, the waist will be in the air. Without camber, when the skier's weight is applied at the waist, the weight will be distributed on the surface closest to the foot, diminishing along the length. Camber presses the tips and tails into the snow, extending the surface area bearing the skier's weight, and thereby improving the amount of edge in contact with the surface. The technique was first introduced by ski makers in Telemark, Norway, and remained largely unchanged through the 20th century.^[2] In 2002, skier Shane McConkey led development of the Volant Spatula, an alpine ski developed for skiing deep powder snow. The Spatula featured "reverse camber" with the tips and tails rising above the waist, in an effort to improve the ski's ability to float on the snow. It was quickly realized that the design was superior in many snow conditions, and as was the case with radical sidecuts, modern alpine skis generally feature some sort of "rocker" design today. This is often subtle, with natural camber at the waist, and rocker at the tip and tail.

Skis also differ in more minor ways to address certain niche roles. For instance, mogul skis are much softer to absorb shocks, and powder skis are much wider to provide more float. These are discussed below.

Construction[link]

Skis have undergone several leaps in design, starting with hand-carved single pieces of wood and evolving into the modern torsion-box design. These can be generally classified into classic wooden, laminated wood, laminated metal and fibreglass, torsion box, and cap designs.

Classic wooden

The classical wooden ski consists of a single long piece of suitable wood that is hand-carved to produce the required shape. Early designs were generally rectangular in cross-section, with the tip bent up through the application of steam. Over time the designs changed, and skis were thinned out to the sides, or featured prominent ridges down the center.

Wood laminates

The perfect wood for a ski is light, flexible in length and stiff in cross-section. Such a wood does not exist. Starting in the 1940s, skis built up from a number of different types of wood glued together became common. By selecting different woods in different areas, the flex pattern could be better controlled. The glue between the pieces of wood also added to the torsional stiffness, twisting the ski along its longitudinal axis requires the sections of wood to move relative to each other, but the glue resisted this motion better than the wood itself. This method also lowered the material costs, as it is generally easier to find smaller pieces of wood, and this was a serious concern when hardwood stocks in Europe depleted.^[3]

Edges

In the 1940s, strips of steel were screwed to the bottom edges of the ski on either side. These maintained a sharp edge and allowed the ski to bite into the snow or ice when they were edged. Simple variations on the theme have remained in use to this day.

Metal laminates

Although a number of companies had experimented with all-aluminum skis in the 1940s, none of these proved practical. It was Howard Head's experiments combining aluminum and conventional wood designs that solved the problem. The Head Standard sandwiched a conventional wood laminate ski between two thin layers of aluminum sheet on the top and bottom. When the ski was torqued, the position of the aluminum sheets above and below the axis of rotation required them to slide sideways relative to the core, something that was resisted by the glue along the entire surface of the sheet. The Standard was dramatically stiffer in rotation, and so greatly improved edging and turning that it was known as "The Cheater".

Fibreglass laminates

One disadvantage of the metal laminates was that they were very "springy" and tended to chatter on bumpy surfaces and especially at high speeds. As late as the 1960s, racers still used conventional all-wood designs. Fibreglass, first widely used in the 1940s, offered an alternative material offered vibration damping, as well as allowing the flex pattern to be controlled along the length of the ski. Several such designs were introduced in the 1950s but the first successful one was the 1959 Toni Sailer Fibreglaski by Fred Langendorf and Art Molnar of Montreal. Fibreglass laminates were made much more famous by the Kniessl White Star and Rossignol Strato during the 1960s, and by the late 1960s they were as common as metal.

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 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 mens 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.

Cap skis

During the 1980s, Bucky Kashiwa developed a new construction technique using a rolled stainless steel sheet forming three sides of a torsion box over a wooden core, with the base of the ski forming the bottom. Introduced in 1989, the Volant skis proved expensive to produce, and in spite of numerous positive reviews the company never able to become profitable. In 1990, the Rossignol S9000 took the same basic concept but replaced the steel with plastics, producing a design they called "monocoque". Now referred to as the "cap ski" design, the concept eliminates the need to wrap the core and replaces this with a single-step process that is much less expensive to produce. Cap ski construction dominates alpine ski construction today.

Beginning in the early 2000s, many ski manufacturers began designing skis and bindings together, creating an integrated binding system. These systems serve three purposes. Firstly, they often use a railroad track design, to allow the toe and heel pieces to slide, which in turn allows the ski to flex deeply, without a non-flexing spot underfoot due to the binding. Secondly, it gives the skier a better control on his skis, since the binding is not only screwed on the ski, but integrated in the ski core via inserts. Thirdly, it requires the consumer to purchase both skis and bindings from the same manufacturer due to the proprietary nature of the system, thus increasing sales.

Types[link]

Many types of skis exist, designed for different needs, of which the following are a selection.

Alpine[link]

Like all skis, the original alpine "downhill" skis were little more than wood planks. Early alpine skis, developed in Switzerland and Austria during the 1890s, were wider, shorter versions of the standard Huitfeldt Telemark model, meant to be more agile in steep terrain and in deeper snow. Rudolf Lettner of Salzburg began marketing steel edges in 1928, enabling the ski to grip on hard snow ice. The following year Guido Reuge introduced the Kandahar binding, providing for heel lock-down and improved control for downhill skiing. Downhill ski construction has evolved into much more sophisticated technologies. The use of composite materials, such as carbon-Kevlar, made skis stronger, lighter, and more durable.

By the late 1980s World Cup giant slalom skiers were getting race-stock skis with deeper sidecuts. In 1991, designers at Elan produced a very exaggerated version of this race ski, and in 1993 introduced a recreational version described by the company as offering a "parabolic" turn shape. This became the prototype of modern "shaped" skis (when viewed from above or below, the centre or "waist" is significantly narrower than the tip and tail). Virtually all modern skis are made with some degree of side cut. The more dramatic the difference between the widths of the tip, waist and tail, coupled with the length, stiffness and camber of the ski, the shorter the "natural" turning radius.

Skis used in downhill race events are longer, with a subtle side cut, built for speed and wide turns. Slalom skis—as well as many recreational skis—are shorter with a greater side cut to facilitate tighter, easier turns. Many ski manufacturers label their skis with the turning radius on the top. For a racing slalom ski, this can be as low as 12 metres and for Super-G they are normally at 33 metres. For off-piste skis the trend is towards wider skis that better float on top of powder snow.

The ski is turned by applying pressure, rotation and edge angle. When the ski is set at an angle the edge cuts into the snow, the ski will follow the arc and hence turn the skier; a practice known as carving a turn. While old fashioned "straight skis" which had little side cut could carve turns, great leg strength was required to generate the enormous pressure necessary to flex them into a curved shape, a shape called reverse camber. When a modern ski is tilted on to its edge, a gap is created between the ground and the middle of the ski (under the binding) as only the sides near the tip and the tail touch the snow. Then, as the skier gently applies pressure, the ski bends easily into reverse camber.

Influenced by snowboarding, during the 1990s the side cut became significantly more pronounced to make it easier for skiers to carve turns. Such skis were once termed carving skis, shaped skis, or parabolic skis to differentiate them from the more traditional straighter skis, but nearly all modern recreational skis are produced with a large degree of side cut.

Reverse Camber[link]

Reverse Camber is a term that describes skis with something other than the traditional camber shape. Reverse camber skis have tips and tails that curve up while the length between them is flat. This allows the ski tip to remain above soft powder snow. The first production ski to feature reverse camber was the Volant Spatula which premiered in the 2002–2003 season. Since then, many manufacturers have experimented with the concept and today rocker and reverse camber can be found in dozens of ski models.

Twin-tip[link]

Twin-tip skis are skis with turned-up ends at both the front and rear. They make it easier to ski backwards, allowing reversed take-offs and landings when performing aerial maneuvers. The turned-up tail allows less application of aft pressure on the ski, causing it to release from a turn earlier than a non-twin-tip ski. Twin-tip skis are generally wider at the tip, tail, and underfoot and constructed of softer materials to cushion landings. Bindings are typically mounted closer to the centre of the ski to facilitate the balance of fore and aft pressure while skiing backwards or "switch", and built lower to the ski for easy rail sliding. Some skis are also manufactured with special materials or a different side cut design under and close to the foot to facilitate rail sliding.

In the past five years twin tips have become popular among youth skiers, ages 14–21. The popularity explosion of twin-tip skis created a push for the inclusion of more terrain park elements at ski areas. Once considered a passing fad, twin-tip skis have become a staple in the product line of all major ski-producing companies worldwide, with a few specializing in twin tips. Line Skis, started by Jason Levinthal, was the first company to market only twin-tip skis. The first twin-tip ski was the Olin Mark IV Comp introduced in 1974. The first company to successfully market a twin-tip ski was Salomon, with their Teneighty ski. While the first person to first introduce the Twin-tip to Salomon was famous Freeskier "Michael Douglas". These skis are used by freestylers also known as freeskiers.

Alpine touring ski[link]

The Böksta Runestone is believed to depict the Viking god Ullr with his skis and his bow

The Alpine touring ski is a modified lightweight downhill ski with an alpine touring binding. Like the backcountry ski, it is designed for unbroken snow. For climbing steep slopes, skins (originally made of seal fur, but now made of synthetic materials) can be attached at the base of the ski. The heel of the ski boot can be clamped to the ski when skiing downhill and released when climbing. The type of ski is mainly used with alpine touring boots, which are rigid but lighter than downhill skiing boots, but may be fixed with a binding suitable for skiing in technical mountaineering boots.^[4]

Monoski[link]

The monoski is wide enough to attach both boots to a single ski. After a brief boom in the 1980s, only a few thousand enthusiasts continue to use it. Due to its extra width and flotation in deep snow, enthusiasts claim it to be a superior powder ski. The monoski is produced by a half dozen companies worldwide in limited quantities.

Telemark[link]

The Telemark ski is a downhill or touring ski, where the binding attaches only at the toe. The Telemark ski was the first ski with a significant side cut, and evolved in the Telemark region of southern Norway early in the 19th century. It was popularized by Sondre Norheim of Morgedal in Telemark, when he demonstrated the ski and the Telemark style of skiing to the public at Christiana, Norway beginning in 1868. The fact that the foot is only attached to the ski at the toes means that flexible ski boots are worn. The primary turning technique involves pushing one foot forward and lifting the heel of the other foot.

Cross-country[link]

Cross-country skis are very light and narrow, and usually have slight sidecut, though some newer skis are a sidecut more like an alpine ski. The boots attach to the bindings at the toes only. Three binding systems are popular: Rottefella's NNN, Salomon's SNS profil, and SNS pilot.

The ski bases are waxed to reduce friction during forward motion, and kick wax can also be applied for adhesion when walking uphill. Some waxless models may have patterns on the bottom to increase the friction when the ski slides backward.

The two major techniques are classical (traditional striding) and freestyle or skating, which was developed in the 1980s. Skating skis are shorter than classical skis and do not need grip wax. The skating technique is used in biathlons. V1 skating is done when going up a hill and one arm is the lead arm which poles ahead of the second with its side. V2 skating is done while going down a hill or on a flat area. It involves poling with every stride of the ski.

Backcountry[link]

The 1903 rendition of medieval Russian soldiers' use of skis to facilitate their movement during winter campaigns.

Skis for backcountry skiing (also known as free range and Big Mountain skis) are designed for unbroken snow where an established track is lacking. Employed by military forces to fight in winter conditions, they are the most closely related modern type to the original ski.

Characteristically 10 cm or more in width, they're often fitted with cable bindings to provide general sturdiness and to make it easier to extract one's feet from deep snow banks, in case it should be impossible to reach the bindings by hand.^{[citation needed]}

Mogul[link]

Skis specifically designed for moguls typically have a different flex pattern, are narrower, and have a smaller sidecut than a common carving ski. The differences let the ski absorb the impact of the moguls with the tip yet have a tail stiff enough to push off the previous mogul.

Jumping[link]

Skis for ski jumping. Long and wide skis, with bindings attaching at the toe.

Custom[link]

Since 2004 a few small companies have emerged in the United States making custom skis.^{[citation needed]} The process begins with a questionnaire and interview to determine what flex, materials and ski shape will best suit the skier's skills, weight and target snow and terrain. Core materials, structural components, base and edge materials can be of superior quality and durability. Customers often design their own decorative topsheets.

Other uses[link]

On vehicles[link]

Skis are fitted in place of tires on snowmobiles, snowcats, snow coaches, and airplanes, among other similar applications.

See also[link]

• History of skiing – the ancient history of skis
• Roller skiing – a type of inline skate that resembles a ski
• Snowboarding – a newer way to ride on snow, on one large board rather than two skis
• Skiboarding – very short, twintip skis
• Ski boot – specially designed boots for skiing
• Ski patrol – patrollers on skis
• Snowshoe

References[link]

External links[link]

• Physics of skiing
• FIS equipment tolerances
• A history of the modern shaped ski
• History of skis from about 1850
• Origin of the laminated ski

Sean Kingston
Sean Kingston on December 29, 2007.
Background information
Birth name	Kisean Anderson
Born	(1990-02-03) February 3, 1990 (age 22) Miami, Florida, United States
Origin	Kingston, Jamaica
Genres	Reggae fusion, dance, R&B[1]
Occupations	Singer, songwriter, rapper, actor
Years active	2006–present
Labels	Beluga Heights, Epic, TM3 Records, E1 Music
Associated acts	Flo Rida, Soulja Boy, Unk, Rick Ross, Iyaz
Website	www.seankingston.com

Sean Kingston (born Kisean Anderson; February 3, 1990) is a Jamaican-American singer. He pursued a music career and debuted in 2007 with the album Sean Kingston.

Early life[link]

Kingston was born on February 3, 1990, in Miami, Florida and moved to Kingston, Jamaica when he was six.^[2] He attended high school in Ocho Rios.^[3] His grandfather was the noted Jamaican reggae producer Lawrence Lindo,^[4] who worked under the stage name Jack Ruby.^[5][2] At age 11, Kingston spent 3 weeks in jail for breaking and entering, and Kingston lived in a car while his mother was incarcerated for identity theft.^[2][6]

Music career[link]

[edit] 2007–2008: Sean Kingston

Sean Kingston was discovered through MySpace by Tommy Rotem at Beluga Heights, and signed to the label in a partnership deal with Sony.^[7] Beluga is a label notable for its focus on discovering and developing artists.^[8] In an interview with HitQuarters label head and producer J.R. Rotem described this process with regards to Kingston:

"Sean Kingston was a rapper when we found him and it was a development process to get him more melodic. At Beluga we essentially refine the talent so that it's more of a marketable product."^[7]

In a venture between Epic Records and Koch Records, Kingston recorded and released the single "Beautiful Girls" in May 2007.^[9] The single, based on the bass line and lyrical "association" of the 1961 hit "Stand by Me" by Ben E. King, reached number one on the US Billboard Hot 100 for three weeks and topped the UK Singles Chart along with many other international charts. Similarly, the song "Me Love" samples the main hook out Led Zeppelin's "D'yer Mak'er", from their 1973 album Houses of the Holy. The song also debuted at number one in Australia, where it knocked off Fergie's "Big Girls Don't Cry", which had been at number one for nine weeks. The song stayed on the Canadian Hot 100 number one spot for over six weeks before getting knocked down to third place by the Plain White T's. "Beautiful Girls" remained at number one in Canada longer than any other song in 2007. In 2007, Kingston was the opening act for Gwen Stefani's The Sweet Escape Tour and for select dates on Beyoncé's The Beyoncé Experience Tour. In 2008, he was one of the opening acts for the Australian leg of Kelly Clarkson's My December Tour.^[10] Since Sean is a Jamaican singer, he got his stage name "Kingston" from the capital of Jamaica called Kingston, Jamaica.

[edit] 2009–2010: Tomorrow

The album Tomorrow was released on September 22, 2009. Big-name producers involved in the album included former Fugee Wyclef Jean; RedOne (of recent Lady GaGa fame); plus Sean's original mentor, J.R. Rotem.^[11] So far, the singles "Fire Burning", and "Face Drop" have been released. Additionally, five promotional digital singles were released leading up to the album.

Kingston co-wrote Jason Derülo's "Whatcha Say". He also found the R&B-reggae singer Iyaz on MySpace and signed him to his record label.^[12] He also recorded the track "Miss Everything" for the UK girl-group Sugababes studio album Sweet 7 which was released March 15, 2010 in the UK. Kingston and DJ Khaled are being featured on Bow Wow's new single "For My Hood", from the upcoming movie, The Lottery Ticket.^[13]

2010–present: Back 2 Life, King Of Kingz and other projects[link]

According to Sean Kingston, he is already working on his next album. The lead single was confirmed to be "Dumb Love". The song's chorus samples 1957's, Come Go With Me by the Del Vikings. The song is also featured in a episode of The Suite Life on Deck which Kingston guest starred on. The album will also feature T-Pain, Nicki Minaj, Kanye West, Flo-Rida, Soulja Boy, Wyclef Jean, Akon and Dr. Dre.^[14][15] The first single from the album is "Eenie Meenie" featuring Justin Bieber, released on March 23, 2010,^[16] which is also included on Bieber's My World 2.0 album. This collaboration with the young star has been the source of much disapproval from the rap community. The second single from the album is "Letting Go (Dutty Love)", which features a verse from Nicki Minaj. It was released on iTunes August 3, while the third is "Dumb Love" and was released on iTunes September 8. Sean Kingston's new song "She Moves" samples Irena Cara's "What a Feeling" from the film Flashdance. This has not been release as a single. A fourth single "Party All Night (Sleep All Day)" was released on December 21, 2010. The song leaked online in December 2010. The music video has already been shot. The video was released on December 23, 2010. Sean said this would be the song of the new year.

Kingston represented the continent of America to sing the Official Theme Song of the Singapore 2010 Youth Olympic Games, Everyone. He collaborated with four other international artists representing their continent, South African Jody Williams representing Africa, Singaporean Tabitha Nauser (Asia), Briton Steve Appleton (Europe), and Australian Jessica Mauboy representing Oceania.^[17] However, Kingston was unable to attend the Singapore Youth Olympics 2010 opening ceremony due to passport mix ups.^[18] Sean was invited to featured on Cash Money Records/former So So Def member Bow Wow on his single "For My Hood". He performed it with him along with DJ Khaled on BET's television program 106 & Park the day after release.

Sean Released his first mixtape King Of Kingz on February 3, 2011 as a free Download only. The mixtape includes guest appearances by Akon, Flo-Rida, Soulja Boy, Justin Bieber, B.O.B and Tory Lanez.

Kingston will release a mixtape with pop star Justin Bieber, called Our World. It will feature about 12–14 songs and includes their versions of songs like "Pretty Boy Swag" and "Billionaire". The mixtape is finished and Kingston showed his fans a preview on uStream on August, 19, 2010^{[citation needed]}. The release date is yet to be confirmed. Kingston also went on to perform on first leg of Bieber's tour. On April 25, 2011, Kingston performed at Cross Roads Hotel in front of 2,000 people in Lilongwe, Malawi. Kingston was recently in Zimbabwe performing there and is scheduled to perform in Ghana in June 2011. He performed a street concert on April 29, 2011, at Utah State University.^[19]

Kingston has announced that his new album will be called Back 2 Life.^[20] He also said in an interview with MTV that he would be completely re-doing the album and that the previous singles will not be on it. According to Sean's twitter the first single off the album will be released the first week in May 2012. Sean linked up with T.I. on set of the video for “Back 2 Life,” the street single off his upcoming album of the same name. The two shot the video in Los Angeles last week with comedian Mike Epps.

Activism[link]

Kingston filmed a public service announcement with Do Something to encourage teens to become active in their communities by forming a Do Something club.^[21] In 2010, he appeared with one of his dogs in an ad for PETA, encouraging people not to chain their dogs outside.^[22]

Jet skiing accident[link]

On May 29, 2011, Kingston was involved in a jet skiing accident in Miami Beach, Florida. Kingston and a female passenger were severely injured when their jet ski struck the bridge connecting Palm Island with the MacArthur Causeway at approximately 6 pm. He was taken to Jackson Memorial Hospital in Miami, where he was placed in the intensive care unit and listed in stable condition.^[1][23][24] He suffered a fractured wrist and broken jaw along with water in the lungs, but was expected to make a full recovery.^[25] On June 24, 2011, Kingston was discharged from hospital and continued his recovery at home.^[26]

Discography[link]

Studio albums

• Sean Kingston (2007)
• Tomorrow (2009)
• Back 2 Life (2012)^[20]

Mixtapes

• My Time (2009) (Tomorrow Pre-album)
• King Of Kingz (2011)
• Our World (TBA) (with Justin Bieber)
• Greatness (TBA)

Awards/nominations[link]

• Image Awards
  • 2008, Outstanding New Artist (nominated)
• MOBO Awards
  • 2007: Best Reggae Acts
• Teen Choice Awards
  • 2007: Choice R&B Track "Beautiful Girls"
  • 2007: Choice Summer Track "Beautiful Girls" (nominated)
  • 2009: Choice Summer Song "Fire Burning" (nominated)

References[link]

External links[link]

Wikimedia Commons has media related to: Sean Kingston

• Official website
• Official UK website
• Sean Kingston on Twitter
• Sean Kingston on Myspace
• Sean Kingston's channel on YouTube