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# The Rotary "Thing" (again) - Page 4

MilesB - To illustrate and support what Rusty just said, look at the tails of skiers A and D in the diagram that is at the top of page 3 of this thread. In neither case does the tail of the ski go outward (ie, cross Mike_M's imaginary line) when viewed by a stationary observer, and that's what's important to the interaction of the skis with the (obviously stationary) snow.

There is a good chance you are thinking about this in the reference frame of an observer sitting at the mid point of the skis (ie, the skier). With this perspective, the tail will always go in the opposite direction to the tips in any pivoted turn (ie, skiers B thru D in that illustration), but relative to the snow, you certainly can construct turns in which the tip goes inward and the tail does not go outward.

HTH,

Tom / PM
Tom, surely you are not suggesting that we ski with our weight on the tails of the skis? As you have shown, that is the only way to turn our feet without moving the tails.
Now if you are talking about applying torque in an isometric manner to an edged ski, that is different from the exercise Rusty described. And I would still describe that as steering.
milesb,

Please expand on what "torque in an isometric manner" is. You got me there.
"twisting"?
Nolo, I have a suspicion he is probably talking about braquage (aka, "two barstool twisting").
---------

Milesb: "...surely you are not suggesting that we ski with our weight on the tails of the skis? As you have shown, that is the only way to turn our feet without moving the tails..."

No, I'm not suggesting that. To be precise, I did not show that "D" (in the above diagram) was the ONLY way to turn our feet without moving the tails to the outside (relative to the snow). Diagrams "A" and "D" were just two examples of ways this COULD occur, not the ONLY ways.

For example, another way to move the tips to the inside and have the tails also move to the inside (albeit by a slightly smaller ammt) is to add a bit of foot-twisting to a carve to get a skarve. Of course one could add a pinch of either B, C, or D to "A" to accomplish this, but as you suggested, "D", isn't highly recommended.

Tom / PM

[ July 18, 2003, 11:48 AM: Message edited by: PhysicsMan ]
nolo, imagine a ski on a 45 degree edge angle, highly bent. Now try to make it carve a tighter turn by moving the tips further inside the turn (don't increase the edge angle.). Because the edge is digging into the snow, there is very little movement possible, but you CAN bend the ski into a tighter arc. As tight as 2-3 meters. I'm sure you've done this.
Thanks, miles. That makes more sense to me than "isometric torque."
> ...Now try to make it carve a tighter turn by moving the tips
> further inside the turn (don't increase the edge angle.).
> Because the edge is digging into the snow, there is very
> little movement possible, but you CAN bend the ski into a
> tighter arc. As tight as 2-3 meters. I'm sure you've done this.

Sorry, but I'm not sure I understand your description. By "bending" do you mean more of the usual longitudinal flex or something else? If the former and you are sticking to your assumption that you aren't going to vary the edge angle, isn't that more of a pressure issue than a rotary issue?

Tom / PM
Sorry, guys, I'm done with this one. [img]smile.gif[/img]
Hmmmmm. Interesting to sit back and read all the discussion going on here. My reaction is to think perhaps this is becoming more complicated than it needs to be. Here's my take:

When a turn is steered the ski is pressure pivoted (twisted), the tail moves out and the tip moves in. This is true no matter how aggressive or subtle the steer, and this includes that form of steering referred to by the ridiculous term scarving, the only difference will be in the amount of lateral movement of the tip and tail. The amount the tip and tail move in relation to each other depends on where along the length of the ski we place the pivot point. Put it at the center of the ski and tip and tail move equal amounts. Move it forward of center and the tails move laterally more than the tips. Move it back and the tips move the most.

All these pivot point adjustments are make by moving our CM fore and aft. I should add that attempting to steer with the pivot point aft of center is the more difficult task because the tips must be pulled uphill, your fighting gravity and momentum.

It has been suggested that steering can occur where only the tip moves laterally, or only the tail moves laterally. Well, ya, I agree that it can be done, but it's one hell of a trick, and I would venture to guess that there are few who will read this thread that will be able to proficiently execute or demo this maneuver. To do it you have to severely leverage against the front or back of the boot, to the point of lifting the majority of the ski off the snow and then, while maintaining that precarious position, pivot on the remaining 12 inches or less of ski still in contact with the snow. We've done these drills in training and only the strongest and most skilled of my students could do these correctly and well. I don't think there are too many instructors teaching the general public that will find themselves in situation where this method of steering would be worth focusing on.

MILESB SAID:
nolo, imagine a ski on a 45 degree edge angle, highly bent. Now try to make it carve a tighter turn by moving the tips further inside the turn (don't increase the edge angle.). Because the edge is digging into the snow, there is very little movement possible, but you CAN bend the ski into a tighter arc. As tight as 2-3 meters. I'm sure you've done this.

Ya, that can be done. I think the easiest way is to toss the CM inside and back, and horse on the tail of the ski. What your doing is directing all the forces of the turn to a small section of the ski rather than the whole ski, the result, more concentration of force so more bend and thus sharper turn. It even used to work on long radius skis, now on shorties it can actually launch you across the hill.
Quote:
 Originally posted by FastMan: [QB]Hmmmmm. Interesting to sit back and read all the discussion going on here. My reaction is to think perhaps this is becoming more complicated than it needs to be. Here's my take: When a turn is steered the ski is pressure pivoted (twisted), the tail moves out and the tip moves in.
You complain about complications and then toss in terminology that I have never heard in all the years I have been skiing, or the four years I have been teaching.

What the heck is pressure pivoting?

Again, when a ski is turned the tail CAN be moved out and the tip CAN be moved in. Displacement of the outside tail "out" has been described by modern technicians as a defensive movement. It is the hallmark of the "heel pusher" or "sperm turner". It's the guy with plastic to plastic boot contact and the buckles about to pop from the leveraging.

The offensive skier has the entire ski moving in the direction desired. It can be done, does not involve any pivot, and does not require any more fore-aft realignment of balance than any other turn.

The best example of this is watching a well qualified PSIA clinician demo wedge christie turns. In a turn to the right, the right ski tip is always moving right and the right ski tail is not pivoted or pulled in towards the left ski. There is a very subtle difference and it is fun to watch when the demo has been mastered.
Rusty,

I would suggest that in order to pass level III you made the turn you described. The timing of the movements are such that the tail of the new outside ski never moves up hill. It will stay "stationery" on the uphill axis while the tip is directed down the hill.
From Tangurey and Tonic
To All

"Its clear as mud and it covers the ground" (can anyone tell me where I remember this line from? maybe a Harry Belafonte[sp] song). The horse is dead lets bury it.

From somewhere in his cups,

Yd
[quote]Originally posted by Rusty Guy:
Quote:
 You complain about complications and then toss in terminology that I have never heard in all the years I have been skiing, or the four years I have been teaching. What the heck is pressure pivoting? Again, when a ski is turned the tail CAN be moved out and the tip CAN be moved in. Displacement of the outside tail "out" has been described by modern technicians as a defensive movement. It is the hallmark of the "heel pusher" or "sperm turner".
Well OK Rusty, that's more like it. No personal references and jabs, you kept it geared strictly to the topic. A bit testy, but much better.

Your right, pressured pivot is a new term to you, but I defined it right in the sentence I used it in as a steered turn. Please read again:

"When a turn is steered the ski is pressure pivoted (twisted), the tail moves out and the tip moves in."

I purposely used the term to get across the idea that a steered turn involves twisting from a pivot point, but I had to add the word "pressured" because the term "pivoting" already has an accepted by most usage in skiing terminology.

Both pivoting and steering involve changing direction by physically twisting (pivoting) the ski in the new direction. The difference is that the movement referred to in skiing circles as "pivoting" is a twisting of the ski while it has little or no pressure applied to it, usually during the turn transition. The skis are redirected, but an actual change of direction the skier is moving in does not begin to occur until pressure is applied to the redirected ski.

Steering is twisting (pivoting) the ski while it's pressured and results in immediate change of direction moving for the skier.

I used the term "pressured pivot" to highlight the fact there is pivoting going on in a steered turn so I could point out how tip and tail displacement is affected by fore/aft pivot point movement.

The heel pusher you refer to is not steering, he is using a different form of rotary to turn his skis. It is usually performed by making an aggressive counter rotation move in the upper body combined with a tail toss. The two moves balance each other. It can also be done with an aggressive rotation of the upper body which pulls the tails into an abrupt outward toss. These moves are NOT steering. Steering is a more refined and controlled twisting of the feet and skis, a more advanced form of rotary. All these forms of rotary are well defined in a post Bob Barnes made here a couple months back, one that was re-posted just recently.

It is hard to be crystal clear in a strictly written forum such as this, as we witness over and over, so I do make an effort to include detailed descriptions of my concepts and terminology. It's usually in there, as it was in this case.

RUSTY SAID:
The offensive skier has the entire ski moving in the direction desired. It can be done, does not involve any pivot

Yes, and it's called carving. Anything less involves some steering or other rotary and requires some degree of twisting (pivoting) of the ski. This is true no matter how refined you think your steering is, it's got to be in there in some amount or your not steering. There is no new magic way to turn a ski.

[ July 19, 2003, 05:28 AM: Message edited by: FastMan ]
Quote:
 Originally posted by FastMan: FASTMAN REPLY: Yes, and it's called carving. Anything less involves some steering or other rotary and requires some degree of twisting (pivoting) of the ski. This is true no matter how refined you think your steering is, it's got to be in there in some amount or your not steering. There is no new magic way to turn a ski.[/QB]
Fastman,

I would argue you have forgotten about gravity.

What about a skier who is traversing a steep slope with both skis on edge who then flattens both skis to some degree?

This skier is traversing to the skiers left, supinates (inverts) the right foot and pronates (everts) the left foot loosing "critical edge angle"?

Will there be a change of direction?

Has there been an accompanying twisting of the ski?

Has there been pressuring?
[quote]Originally posted by Rusty Guy:
Quote:
 I would argue you have forgotten about gravity. What about a skier who is traversing a steep slope with both skis on edge who then flattens both skis to some degree?
Well son of a gun, I guess ya got me. Yes, I had forgotten about flattening the skis while in traverse and going into gravity driven sideways free fall. Yep, your right, that will change your direction of travel. It can be exciting too, because you never know just where your going to end up or what your going to run into. Those more timid souls may resort to steering their skis back into the fall line, but heck, where's the fun in that?

I have now, with your help, thought of a couple more ways to change direction without the use of rotary. Skiing off a cliff will do it twice for you, once after you launch, and again after you land.

And careening off another object, such as a tree, boulder, lift tower or another skier will change direction for you without the need for rotary also. With this one you even have a bit of control over the resulting direction if you are good at geometry, it's rather like playing pool.

Thanks Rusty for bringing my attention to my silly oversight.
Bouncing of Rusty while he is standing in the middle of a run talking about something he read last night would be another way of turning without rotary ... BUT only if the manoeuvre, happened in the belly of the turn, on a pair of 156 slalom skis on a nice groomed blue slope and did not include "intent".

Oz [img]smile.gif[/img]

[ July 19, 2003, 03:07 PM: Message edited by: man from Oz ]
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