Originally Posted by ssh
I don't think so, Si, but I could be wrong. In my analytical brain, there are additional subtleties here that likely overcome this. What I "see" in my imagination is my rotary doing two things: effectively differentially pressuring the tip to cause it to flex more deeply than it otherwise would, thus tightening the radius of the arc of the ski. I also see it "digging" the edge into the snow more, thus keeping the tip from breaking loose while that additional flex is applied. The subtlety comes in while doing this in a way that doesn't effect a break-out of the tail.This tells me that you do not understand at all the turns that I am describing. I know these turns. Ask cgeib, Noodler, or Rick if these are the kinds of turns I make. For reference, this is what Noodler said about my turns during a demo day when we skied together
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.)Riding the arc of the sidecut is definitely easier and recruits far fewer muscles! Of this there is no doubt. I enjoy doing that very much, and often play with tightening my turn arc by increasing my edge angle. The point that I seem unable to communicate is that this is not the only way to do so, and that there are times when it is impractical or not physically possible. It's nice in those circumstances to have alternatives.
I think that I probably am, but I haven't considered the physics long enough to know that for sure.How is rotation of the femur different from "steering"? Are you talking about what Uncle Louie has described to me as "resultant rotary"? That rotation of the femur in the hip socket can be applied or allowed. The results are different, but not necessarily visible to the eye.Certainly, a weighted release as you describe is possible, but unless you're on very steep terrain, the skis will not seek the fall line very quickly. They won't even find the fall line unless you move your pressure to the tips (if you don't, you'll just sideslip). They will also not go beyond the fall line, so any turning to a stop will require riding the arc or pivoting the ski (or both). When doing releases, most people naturally pivot their skis in and through the fall line, even when they aren't conscious that this is what they are doing.
BTW, the first time I did this was with a staunch PSIA Level III.
Guess all I can say is that I am not at all sold on the physics as you are imagining it. First I don't see how a torque applied to the ski (surface) can "differentially" pressure the tip. Second, if the torque helps dig the ski tip in then it's going to have the opposite effect on the tail. Still seems to me the most effective way to bend the ski further into the turn is via increased tipping and edge angle.
I think I do understand the turns you are describing. It's just that what I interpret as the physics and mechanics of what is happening is somewhat different than your interpretation.
In terms of "rotary" my point is the it is quite possible to rotate the hip (i.e. femur/pelvis joint) for tipping without applying any significant rotary torque to the ski.
Yes the pivot slip like drill I talked about needs to be done on relatively steep hardpack if the tips are to seek the fall line in a short time/distance. I meant to include that but missed it.
I don't believe that "rotary," as defined by a torque applied to a ski to rotate it in the plane of its surface, is something that shouldn't be used. What I have found for myself is:
1) If the balance and movements for effective tipping are well learned then producing rotary is greatly simplified. I don't think the vice versa works nearly as well. An approach that focuses on tipping is much better for teaching good skiing balance and movements than one that includes "rotary."
2) The more I develop in my skiing the more I use tipping and the less I use "rotary." Disclaimer, I'm mostly an off-piste skier who spends no time in gates or racing. So, I have little or no experience talking about "rotary" in the gate environment. However, when I see clips of World Cup level racers I don't see them using "rotary" to nearly the extent that some here claim.
3) In spite of 1) and 2) I still use "rotary" at various times. When I ski with skiers better than me (I regularly get such experiences including some with a few world class skiers) in varied terrain, I invariably find that they use "rotary" much less than I do as they have the ability to maintain balance through steep, crux filled, terrain and thus more effectively continue to use their edges.
4) This one will undoubtedly get me in trouble as a gross generalization but I'll say it anyway: As a group, instructors who ski at a reasonable accomplished level use more "rotary" than other equally or more accomplished skiers who are not instructors. Given my stated feelings about replacment of "rotary" with tipping as one's skiing advances, this implies to me that in general, instructor development (and teaching?) (and posts here on Epic?) focuses too much on "rotary."
Guess I'll run for cover now
: as I've observed such expressed sentiment here at Epic to be equivalent to extolling the virtues of "rotary" over at Real Skiers