The skier gathers speed as he zips down the inrun to the takeoff. The track is one half to one inch deep in hard snow. The first part of the inrun is straight with an angle of 28 to 36 degrees. The next section is a transition curve leading to the takeoff. This curve is usually a circular arc and its radius is limited by the rules for ski jump design. The radius of this curve is denoted by R1 and because there is also a transition below the landing, people simply refer to the inrun transition as R1 (in the same spirit, the transition below the landing is frequently called R2). If you let cartoon illustrations be your guide, you might think that the takeoff shoots the ski jumper up into the air -- not so! Takeoffs actually angle downward at 7 to 12 degrees. And the track is not curved all the way to the end of the takeoff, the last section is straight. The rules for ski jump design prescribe that the length of the straight part of the takeoff (the table) be chosen so that the skier traverses it in one quarter of a second. At the edge of the takeoff (the lip) the jumper leaps up and out in a subtle and difficult compromise between wanting maximum upward thrust and wanting never to have his body in a full vertical position. The air resistence encountered by a vertical head and chest erodes the skiers forward velocity and cuts precious meters off his jumping distance, so he tries keep the chest low and still exert great thrust with the legs. In the old days, ski jump landings were flat just ahead of the takeoff,
then rolled over abruptly at the knoll and ran straight down to the
transition. This was bad design; today the landing will have no noticable
knoll, instead it will have one smooth curve, almost to the top of the
transition. The most recent design rules permit no straight section on the
landing. The K point on the landing marks the place where the bottom of the landing meets the top of the transition (R2). According to the rules, jumps are tolerated only a few meters past the K point. If jumpers exceed K, the takeoff speed is reduced by using a lower start. The jumpers goal, of course, is to fly as far down the hill as possible, then land gracefully and ski through the transition to come to a safe stop before the end of the outrun. Hill size is designated by the distance in meters from the takeoff to the K point. (Until just a few years ago, hill size was designated by the distance to the norm point P which is approximately 80% of the distance to K. For example, the 70 meter Olympic jump in Lake Placid became the K-86 without physical modification. In writing or conversation, people often include the "K" to make sure that it is understood that they are using the new designation.) A measuring tape is stretched from the edge of the takeoff downward through the air until it meets the knoll on a tangent. Then the tape is laid along the landing surface down to K. This tape is also used to measure the distance of each jump. The distance of a skiers jump is marked at a point directly under the ski boots when the entire skis contact the snow. The distance measurers must be careful not to be misled when the tails of the skis drag before the jumper lands. Next, meet some great Ski Jumpers of the present and the recent past.
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