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Times for lines - Page 2

post #31 of 37
Quote:
Originally Posted by Rick View Post




When I've used 21+ meter GS skis on that course the times have dropped.  27m on that slope would push the limit of arc to arc.  Think super slalom type of set on gentle terrain.  They also wouldn't provide the variety of possible carved turn shapes the 13m skis do.  

I think these variations help confirm your conclusions about the importance of line selection.

When you picked a ski that could be run cleanly on different lines, you achieved a measure of independence of the line as a variable in your experiment.
post #32 of 37
The force of the ski in and on the snow also comes into play. The quick hard turns a straight line uses are slower than longer drawn out turns of a round line that don't require so much focused force to make the turn happen. It is a balance between directness and turns with the least amount of friction and loss of energy.
post #33 of 37
Agreed, you definitely have to find a good balance of the two, also a turn that matches the ski/skier is important. A skier that has  a ski too stiff will have to make quick movements to properly flex the ski, and a ski too soft ends up with over flex or a very slow (too drawn out) turn. A proper ski and flex allows the ski to store energy as the skier enters the turn and with proper form the skier can retrieve that energy as the ski "unloads". 
Quote:
Originally Posted by MastersRacer View Post

The force of the ski in and on the snow also comes into play. The quick hard turns a straight line uses are slower than longer drawn out turns of a round line that don't require so much focused force to make the turn happen. It is a balance between directness and turns with the least amount of friction and loss of energy.
post #34 of 37
Thread Starter 
Thanks for the feedback and discussion, guys.  I'm glad you liked seeing the data.  Yes, Mogul, I chose those skis to provide a wider range of turn shapes for the test.  It worked well.  

TDK, by "tight line" I didn't mean close to the gate, I actually meant a straighter line by moving my aiming point in.  In the round line run I linked my turns so that the transition happened half way between the gates, where one turn ended the new turn immediately began, and the turns were a consistent arc from start to finish.  In the straighter (tight) run, I moved my aiming point in, waited longer to start my turn and then consolidated its execution it into a smaller amount of time and distance.    Both the round line and straighter line placed the turns apex at the gate, but the in the straighter run I didn't have to fight gravity as much.  The result of that is a faster time, just as the test data shows. 

MastersRacer and Mogulmuncher is right, push the line too much and speed gains can become speed losses.  Less fighting of gravity pays off only up to the point that speed gained by it can be carried through the condensed turn.  With experience you begin to be able to feel when you're doing that successfully, or you're dumping the speed you gained.  It was interesting that in doing this experiment I could clearly feel the differences in speed via the various lines and tucks, even when they were a mere few tenths.   Part of learning to optimize line is developing a good sensory awareness of speed.  It comes with experience.

And tdk6 is right about what happens when you get to close to the gate with the feet.  Edge angle is lost, the radius of the arc grows, double turns happen, you get late, and speed goes out the window.  It's a common flaw in developing racers, and why I included it in the test.  In an effort to straighten out lines newer racers often pinch the gate with their feet and destroy their turn.   They have to leave room between their feet and the gate for their body to have room to incline into a high edge angle.  

BTW, I now notice that I didn't explain the chart I posted.  For those not familiar with NASTAR scoring, the first row of numbers is my time, the second row is the NASTAR handicap that time produced.  The faster the time, the lower the handicap.  
post #35 of 37
Thread Starter 
 WaStraightLine, good point about capturing the energy of the turn as you exit it.  It's clear to see when a skier is successful at that, they will explode with acceleration as they exit the turn.  When not successful, there is an obvious stall.  It's something you feel too as you ski.  
post #36 of 37
Rick, IMHO the biggest difference between SL and GS other than the obvious length in distance between gates is the gate itself. Because of the construction you cannot block it like you can in SL. The result of this is that you need to ski further away from the gate in GS than what you do in SL. This is where most aspiring racers struggle. They come in too close and they cannot incline because their body will not be able to pass on the inside of the gate like in SL where you have to do it. You need to ski arround the gates in GS. Typical for low level GS club racing is that everyone skis very close to the gates causing a rutt to develop. And piles of soft snow is piled where you actually should be skiing. Especially in races were its snowing this is a problem.

So my definition of a straight line is what you Rick did when you skied "too close to the gates". Maybe my definition is wrong since you could ski the fast line slow and round but still end up close to the gates. I asumed you whent fearly straight at the gates. 

I think that your experiment shows very clearly a learning curve. Start out skiing round and far away from the gates in an upright stance. Then try to go more straight and a bit closer but do not go very close in a half tuck. Then, for best performance you should be going as straight as possible and hit each gate with your hipp in a tuck.
post #37 of 37
Thread Starter 
Quote:
Originally Posted by tdk6 View Post

Rick, IMHO the biggest difference between SL and GS other than the obvious length in distance between gates is the gate itself. Because of the construction you cannot block it like you can in SL. The result of this is that you need to ski further away from the gate in GS than what you do in SL. This is where most aspiring racers struggle. They come in too close and they cannot incline because their body will not be able to pass on the inside of the gate like in SL where you have to do it. You need to ski arround the gates in GS. Typical for low level GS club racing is that everyone skis very close to the gates causing a rutt to develop. And piles of soft snow is piled where you actually should be skiing. Especially in races were its snowing this is a problem.
 

Yep, right on.  GS and SL are completely different animals for the very reason you state.  This is also why narrowing foot separation is so much more important in slalom.  In slalom, narrowing the stance allows the Center of Mass to take a more direct path down the hill.  In GS it makes little difference because the gate imposes the limitation on where the Center of Mass must be.  Moving the inside foot closer to the outside foot will not allow you to move your outside foot closer to the gate, like it will in slalom.  

And right on about the bad ruts too.  Pinching the gate causes the rut to be too close to the gate.  It also causes the racer to get late and hard on the edge below the gate too, so the same gate can have multiple bad ruts.  When I did this test, with all the various lines, it was in soft snow and I was constantly crossing ruts.  I just barreled right through them.  I had no choice.  




Quote:
So my definition of a straight line is what you Rick did when you skied "too close to the gates". Maybe my definition is wrong since you could ski the fast line slow and round but still end up close to the gates. I asumed you whent fearly straight at the gates. 

Yes, I separate line from the distance you are from the gate while skiing that line.  The same line can be skied at various distances from the gate.  It just depends when you start your turn.  The double turn is an example of starting too soon while trying to ski a particular line. Line simply refers to how round you turn, and where you place the apex.  The straighter your line, the less you're fighting gravity, so the faster you go, as long as you can carry your higher speed through a clean turn.  G forces go up with the speed that comes from a straighter line, and the need for superior strength and technical skills go up too.

My use of the word "tight" probably threw you.  For clarity I should have said "straight".  Though I tend to interchange tight and straight, tight can also have other meanings, such as in how a course is set.  

Quote:
I think that your experiment shows very clearly a learning curve. Start out skiing round and far away from the gates in an upright stance. Then try to go more straight and a bit closer but do not go very close in a half tuck. Then, for best performance you should be going as straight as possible and hit each gate with your hipp in a tuck.

Good catch, tdk6.  This test was also suppose to represent a learning progression.  
Edited by Rick - 4/16/10 at 9:19am
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