Not so long ago, skis were wooden
planks with one end turned up and grease or wax smeared on the bottom to help
them slide. In the 1990s, under the influence of snowboarding, there was a
revolution in ski design, producing the basic principles and wide variety of
applications we see on the slopes today.
Just for the record, the basic
principles of manipulating a snowboard and manipulating a pair of skis are
identical. The difference is all in the physiology driven by the position of the
human attached to the gear in question. In this blog entry, I'll focuses on skis; however, the ideas can
be applied to snowboarding as well.
The revolution in ski design has allowed
recreational skiers to ski more comfortably, efficiently and in a wider range
of conditions than allowed for by previous designs, as well as allowing ski
racing to push the envelope of speed and maneuverability in new ways.
Four Basic Components
There are four basic
components to the design of a ski: "sidecut" - the difference in width of the
tip, tail and waist of a ski; overall width - the height at which the skier is
"lifted" off the ski; stiffness; and camber. The variations in these factors
influence how a ski performs, and skis are designed to manipulate these factors
for different purposes.
Today's skis are generally wider, contain more "sidecut", and lift the skier higher off the "deck" or top of the ski. In World
Cup and Olympic Racing, governed by the FIS (Federation Internationale du Ski),
there are rules about the first three design components of skis, which are
intended to even out competition and make technology less of a factor, much
like in auto racing. Also like auto racing, manufacturers tend to build the
skis to the outer limits of the rules, making the outward differences between
skis a matter of degree and construction technique.
Ski Characteristics
In combination
with gravity and the skier's manipulations, these four components help to make
a ski turn. Sidecut, the arc created from the difference in width of the tip,
waist and tail of a ski, influences the general radius of a turn that a
particular ski is designed for. Skis meant for Slalom racing tend to be
somewhat shorter, with more sidecut (tighter arc, tighter turn). In the high-speed events (Super-g and Downhill), the skis tend to be longer and have
somewhat less radical sidecut (longer = more stable at high speed; less
sidecut = longer arc, less tight turns).
Skiers "turn" skis
by moving their bodies to apply the ski in different reactions to gravity.
Movements that allow gravity more effect make the ski/skier go faster,
movements that put the ski in opposition to gravity slow the ski/skier down.
There are three general movements that skiers use to manipulate a ski: twist,
or rotation around the vertical axis; tilt, or turning a ski up on its side
(called "angulation"); and applying or releasing pressure to the ski (skiers
also adjust where on the ski the center of pressure is, by moving their center
of gravity forward and backward over the ski).
That is really it. There isn't
anything else you can do to a ski - twist, tilt, push. Combining those forces
makes a ski turn or not.
About the Author
Jay Stott is a writer, photographer, teacher and general 'ner-do-well.
Before his current career arc, he spent 15 years teaching skiing and
leading adventurers in the wilds of the American West. He currently
lives in North Central Colorado. Visit him at jgstottphotography.com.
| 
Re: How Skis Work
