Ski 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 used in downhill race events are longer, with a subtle side cut, built for speed and wide turns.
The swallowtail allows the two tips to move independently, reducing this torsional force and, in theory, keeping the edge in firm contact.
These designs often lack sidecut as well, relying on their interaction with the snow to provide the curving shape that causes the ski to turn smoothly.
[5] One disadvantage to the parabolic shape is that it was much wider at the tip and tail, producing a design with considerable rotational inertia.
In spite of the larger "shovels" at the tip and tail, the overall area of the ski was reduced, which led to them tending to sink in soft snow.
In 1998 he was testing the Huckster with his friend Scott Gaffney, who reported that his bent Chubbs skied better than the new design because the tips didn't sink in the snow.
McConkey took the design and used it to produce the radical Volant Spatula in 2002, which featured not only a banana-like reverse-camber but also a negative sidecut radius.
On firm snow the skis were difficult to turn at all, but in powder the tips and tails bent up to produce the curved shape that caused them to carve.
Many of these have moderated their camber and sidecut to be more traditional, allowing them to be used on the trails as well as powder, but retain the very wide bases and other features of the rocker design.
Following the introduction in 2003 of the Volant Spatula, designed by Shane McConkey, "rocker" skis became popular in the North American market.
European skiers generally remained committed to full-cambered skis designed primarily for carved turns.
In 1993 the Elan SCX introduced a radical sidecut design that dramatically improved performance of alpine skis.
Other companies quickly followed the Elan SCX design, and it was realized in retrospect that "It turns out that everything we thought we knew for forty years was wrong."
[12] Early modern skis, made in Telemark, Norway by Sondre Norheim,[13] were handmade from a single piece of hardwood and featured a relatively modest sidecut of about 4 to 5 mm.
Taking a pair of the company's standard hickory Rocket skis, they cut away wood until they produced a 15 mm sidecut.
[15] In any case, wooden skis of this era did not provide the torsional stiffness required to benefit from the performance sidecut now adds.
Hiatt and Groswold's experiment required such a deep sidecut that the waist had little vertical stiffness, another problem for the design.
[16] The Backhill was extremely low-tech in comparison to contemporary ski designs, consisting largely of a sheet of plywood.
[17] Experiments with slightly greater sidecut on skis did appear during this period, including the Head Yahoo and especially the Atomic Powder Plus.
[16] Further developments followed due to changes in competitive giant slalom, as the gates were moved further apart and resulted in much more turning.
In spite of reports that these skis were easier to turn, they were considered specialty items and the designs offered only to the race and performance markets.
Meatto and co-designer Ed Pilpel decided to experiment with a radical sidecut as a way of improving turns.
They solved this by cutting the ski in half longitudinally, leaving the curve only on the inside edge, which powers the turn.
The company produced 150 pairs to demonstrate at the SIA trade show in 1986, but no one purchased the odd-looking asymmetrical "Albert" design.
The disadvantage to a pronounced sidecut is that the ski will be less stable at high speeds, preferring short, quick turns.
In a reverse sidecut, the tip and tail are a normal size, but the ski becomes extremely wide at the waist, giving it an ovaline shape.
These constructions are thought to provide maximum flotation in extremely deep powder, but they are useless on hard snow.
