Originally Posted by Lonnie
Now here is something we can disagree on. Your 100% wrong. Rotation has EVERYTHING to do with how much pressure is on our skis at anygive time. How much pressure build up is there in a straight run down the fall line? In a hockey stop? Pressure builds when we change direction. It's why dragsters have tiny front tires and F1 cars have big front tires. We change the direction of our skis by turning them. That is where the pressure comes from.
Hmm. B-) I dont' think we're 100% in disagreement actually... confusing a few words perhaps. The word rotation is often used to mean different things. I think of rotation as an action, not a position. You refer to the skiis being positioned 90 degress from the direction of travel even though you used the word "rotation". That is a position, not a movement. I thought you were referring to movement when you said rotationn before. I think you meant position.
It is definitely true that all of what I said above about G forces is also effected by the angle our skiis have in relationshiph to the various G forces that are acting on us, gravity and centrifigal. A hockey stop is an interesting example because its pretty much only gravity. When you position the skiis 100% sideways, then in theory you are hoping to turn 90 degrees rather instantly. Of course your skis won't do it. You will experience tremendous force of gravity and momentum and you will out of neccessity have to slip your edges a bit as you slow down until you can finally handle the pressure enough with your legs to stop. This agrees with my statements 100% above. the pressure under your feet is you pushing in the snow against the G forces acting on you.
If you position the skiis at a smaller angle and try to hold back the G force pressure with your legs...the angle of the skis has not changed anything about the G forces. However what happens is that you feel less pressure because some of the energy is displaced as the skis move forward. If you point the skis straight down the hill of course they move very fast forward and you don't feel like you are pushing against any G forces at all. Slightly angled and you feel a bit of pressure that you are pushing against while some of the G forces are being displaced into the forward movement of the skis, but not quite as much as straight down, etc..
The pressure you feel under your skis is all related to pushing back against the G forces. the more you slip the edges the less pressure you feel since you are allowing the G forces to win, and the more you hold your edges if you can, the greater you will feel your legs pushing back against those G forces. Equally, the closer your skis are to being positioned 90 degrees from the direction of G forces...the more forces you are going to feel under your feet but if you reduce that angle..some of the forces can be displaced into a forward direction thrust of the ski.
Additionally, direction change adds new G forces in addition to gravity. that is why direction change has a great impact on the G forces you feel, in addition to gravity. And of course as you pointed out, how hard you push against those G forces is how you feel it in your feet..which is indeed a combination of how much you slip your edges or not, and what kind of angle your skis are against the G force vector.
If you haven't read the book yet, I highly reccomend you read Ron LeMaster's books which explains the physics of skiing better than I've seen anywhere else.