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# 4 Questions - Page 15

Quote:
Originally Posted by simplyfast

Hey Lars,

Don't we all look just for that one way of skiing "correctly"?

Would be a great topic actually, first can you even talk about a "correct" way of skiing and if not, what determines a better way to ski, is it to be faster or maybe more gracious or just so that you will prevent falling?

Edit: make that 15 pages...

Another 14 15 page topic that would provide one of two scenarios depending on your point of view:
1. 14 15 pages with hundreds of answers
2. 14 15 pages with no answers
Well then again why don't we all just have fun. Hope you guys have snow already, enjoy your season.
Quote:
Originally Posted by BigE
The flaw in your argument is the fallacy of equivocation. You use the term local steering angle and steering angle as saying the same thing -- equivocal. They don't.

You use the term LOCAL STEERING ANGLE to come up with these crazy definitions of positive zero and and negative angles, then you claim that the LOCAL STEERING ANGLE = STEERING ANGLE.  So even though the ski is turning the skier, you claim the steering angle is zero.

NO.

Are we back to that again?  Ghost I thought you were finally beyond this.  Steering angle is never zero in a ski turn.  There is no such thing as negative steering angle in a ski turn either unless you're catching an edge.

Quote:
Originally Posted by Ghost

Maybe there is a typo.  Where did I say local steering angle = steering angle.   The steering angle of the whole ski is the average of all the local steering angles.  Force = pressure x area.  Force is the integration of pressure over area.  The net force acting on the whole ski is what matters.  Its direction is what counts.

I want to say I somewhat agree with at least the idea that the entire ski does contribute in some way to the overall steering angle effecting the skier.  It may be that the area under the foot has more of an influence then the areas at the tip and tail, and maybe significantly so, but they are not totally insignificant.  Its not a simple average.  There are aspects related to the fact that the ski is bent and flexible to a point.  Consider also that the pressure pushing on the tip and tail is also not pushing at a 90 degree angle to the base of the ski, compared to under foot.  Wait, that also changes as the skier moves fore-aft too.  So many factors.  Its not simple.  To say that the tip and tail influence the skier as much as underfoot is just not accurate, but its also not accurate to say that they have no influence at all in terms of moving the skier on a radius.

The self steering effect of the ski has more to do with taking the "average" of the front end of the ski and the average of the back end of the ski and if there is a difference, then there will be a rotational aspect happening on the ski (which is even required during arcing, I'm not talking about pivoting with skidding neccessarily, though that is what would happen if that rotational aspect becomes big enough.

And getting back to the first paragraph, if the front and the back end up creating some rotational torque between them, then a portion of their pressure contribution will be squandered away on that instead of contributing to moving the skier on a radius.

One reason arcing is so efficient is because the steering angle is minimized, the self steering effects is minimized.  Pressure along the entire length of the ski is definitely contributing to moving the skier on a radius, but I contend that the local steering angles will be very close to equal along the length of the ski at that point, which is why the self steering effect, the rotational torque, has been minimized.

Quote:
Originally Posted by Lars

Well Greg, I'm going to admit that I haven't answered all the questions. And I'm also going to admit to being confused here because there's been at least 14 pages of contradictory answers and theory.

Which just proves my theory that there is no "one" way to ski correctly.

This thread stopped being useful in terms of how to ski better a long time ago.  In terms of correct and incorrect, There are many correct and many incorrect theories floating around.  The point is, there is more than one way to skin a cat, but there are also many totally innappropriate ways to skin a cat.  I wouldn't wanna try it with a spoon.

At any rate, this thread started out as an attempt to discuss some possible correct ways to steer skis, but it has been derailed with a montage of ficticious ideas about physics, boat rudders, negative steering angles, and any number of things have not contributed one iota towards helping anyone understand how to steer their skis better.

Quote:
Originally Posted by Ghost
My example boldly states that a skier will turn with zero steering angle, so long as a force exists on the edge.

That force exists, because even though the edge currently (at that instant) is pointing in the direction of momentum, it IS changing because the ski is carving in a circular groove.  It is the rate of change of momentum that varies with force, and it is the rate at which the edge angle is changing that gives rise to the force.  Thus the force is speed dependent and radius dependent and = MV^2/R, and may be applied exactly toward the centre of the arc.

No work done by the turning force against the skier, only loss is due to friction.  Ain't carving edge-locked arcs grand?  Isn't it so much more efficient than skidding steered turns.

Quote:
Originally Posted by BigE

Your example only works without friction.  As soon as you add friction, you need to have a non-zero steering angle.

friction definitely contributes, but that is not the only thing Ghost keeps missing.  Ghost contends that the pressure on the edge is enough to move the skier on a circular radius.  That is part of it, yes.  However, the instant a skier moves towards the center on the path of the radius, their pressure on the ski will be lost entirely unless steering angle is present.  The pressure can not continue to exist without the steering angle.  The steering angle HAS to be there.  Steering angle is what establishes that lateral pressure to begin with and as the skier moves inside, steering angle has to remain in order to maintain the pressure.

If you are talking about a ball on the end of a string, the string is attached to the axis of rotation, providing an anchor point which provides tension.  That constant tension is what continues to provide this centripetal pressure.  If you're talking about the moon around the earth, there is gravity.  If you are talking about a car, there is no gravity or string tension, but the steering wheel remains turned in the direction you are turning.  Etc etc etc...  Centripetal acceleration is provided by the pressure, but the pressure only exists BECAUSE of steering angle.

As soon as this is understood, then perhaps we can have a more constructive discussion about how to manipulate that steering angle in our skiing.
Quote:
Originally Posted by HeluvaSkier

Edit: make that 15 pages...

Another 14 15 page topic that would provide one of two scenarios depending on your point of view:
1. 14 15 pages with hundreds of answers
2. 14 15 pages with no answers

Third option:

3.  14 15 pages with only one answer -- to this spring's "Why Don't More Skiers Take (or Take More) Ski Instruction?" thread on why so few skiers take traditional ski lessons.  (Watching C/PSIA certs reasoning out the nature of ski turns in this thread has definitely been an eye-opener for me.)
Quote:
Originally Posted by sharpedges

Third option:

3.  14 15 pages with only one answer -- to this spring's "Why Don't More Skiers Take (or Take More) Ski Instruction?" thread on why so few skiers take traditional ski lessons.  (Watching C/PSIA certs reasoning out the nature of ski turns in this thread has definitely been an eye-opener for me.)

I actually see it a bit differently (perhaps a topic for a different thread). I was involved in the creation of this forum and it was intended to allow for the discussion of the technical aspects of skiing between interested "technicians" - not necessarily as a way to develop an instructor-student dialogue. That said, I still think that if you can't get your point across in 15 pages of re-hashing the same idea, the point that one is trying to make is either not worth making, or its communication needs to be revisited and simplified. This "stuff" isn't that hard. ...Just saying...

Carry on.
Quote:
Originally Posted by simplyfast

Hey Lars,

Don't we all look just for that one way of skiing "correctly"?

Would be a great topic actually, first can you even talk about a "correct" way of skiing and if not, what determines a better way to ski, is it to be faster or maybe more gracious or just so that you will prevent falling?

Quote:
Originally Posted by HeluvaSkier

Edit: make that 15 pages...

Another 14 15 page topic that would provide one of two scenarios depending on your point of view:
1. 14 15 pages with hundreds of answers
2. 14 15 pages with no answers

Despite being another 15+ page topic, I think the discussion would reveal a lot of interesting information.
Just to he fair Greg, a good deal of the input on this thread is NOT from accredited instructors.
Quote:
Originally Posted by BigE

Your example only works without friction.

.    BIGE agrees it works except for friction.  BTS must have his almost zero steering angle underfoot.   I'm not going to fight with him over that infinitesimal thing.  I think it's time to declare a Victory and move on.
Quote:
Originally Posted by borntoski683

Just to he fair Greg, a good deal of the input on this thread is NOT from accredited instructors.

And, to be perfectly fair a good deal is from those who are not accredited physics instructors.

How about picking up on the original 4 questions?
I'd like to know your definitions of steering and steering angle are without having to plow through pages of math and physics. What is it that you actually agreed on?
That everyone should read Ron Lemaster -- especially Ultimate skiing.

The work on this material in the book is done in concert with an accredited physics professor.
Quote:
Originally Posted by borntoski683

Just to he fair Greg, a good deal of the input on this thread is NOT from accredited instructors.

Just to be fair to Greg, he did not suggest that it is or isn't from instructors.  I did.  A quick scan through the thread suggests that over half of the input is from instructors.  I'm also fully aware that non-instructors have also been active in the thread, as is appropriate and desirable.  After 15 pages and 22 days the discussion still hasn't shown signs of converging to a consensus or to a clearly stated set of opposing views.
The only bones to pick are the notions that a zero steering angle turns the skier and that the tips and tail are significant contributors to turning the skier.  Both points are dismissed by what Lemaster has written.

The bulk of the bandwidth has gone to defend Lemaster.
Quote:
Originally Posted by Lars

Well Greg, I'm going to admit that I haven't answered all the questions. And I'm also going to admit to being confused here because there's been at least 14 pages of contradictory answers and theory.

Which just proves my theory that there is no "one" way to ski correctly.

Here, Lars, I'll provide you with a summation.

* If you tip your skis on edge they carve.
* If you tip them higher they carve sharper.
* If you put your skis on edge and twist your feet you steer.
* If you twist harder you steer sharper.

And in my book your theory is actually reality.

Now, what was that about questions or something?
What does LeMaster have to say about the steering angle while skating BIGE?
Rick, since you are able to state things concisely: what is steering angle?
Ghost,

I don't recall. Can you fill me in?.
Quote:
Originally Posted by MastersRacer

Rick, since you are able to state things concisely: what is steering angle?

MR, there's a good reason I don't use the term.  It's not a simple one to explain.  LeMaster is a pretty good communicator. He spent 2 pages in his book trying to do it, and after 15 pages of trying to interpret those pages, look where we stand.

My feeling is the confusion lies in the multiple usage of the term.  It can describe the angular difference between the direction of travel and the direction the skis point, as happens in a skidded turn.  It can also describe the bend in the ski, as happens when carving.  And it can just describe the nature of the sidecut built into the ski.

I keep things simple by using another term.  Skid Angle.  It referes to one thing;  how much of an angle your skis are pointing away from the direction you're actually going.  The bigger the angle, the bigger the skid track, and the slower you go.

www.yourskicoach.com/YourSkiCoach/skid_angles.html

Skid Angle: it's clear, it's simple, and the average student can quickly grasp the concept and learn how to put it to use.  It's all they need to know.  Once you move into carving it's equally simple to just talk about tipping, how it bends the ski, and how it affects turn shape.
Thanks Rick,

I visited your site (again) and I (still) like your approach. Simple. Direct. Effective.

MR
Skid angle:  It doesn't tell you why you turn.

Do instructors need to understand the physics of body/ski/snow interactions any more than a driving instructor needs to understand internal combustion engines, universal joints and rack and pinion to be able to teach effectively? I don't believe so. Both need to understand the realities that exist. Certain actions will lead to a certain beneficial results.

• Tipped edges will cause a ski to engage the snow and carve.
• Different amounts of tipping make different sized carved turns.
• Add steering and the ski will skid so you can make different sized turns with different edge angles and differing amounts of steering.
• Skidded turns are a blending of the grip of the edge vs the slipping of the edge induced by steering: edge angle and steering effort can be changed in unison or independently to control the skid.
• Skidded turns of the same size will result in slower speeds that carved turns of the same size.
• A flat ski in motion will generally seek the fall line.

Those are the basic building blocks for virtually all turns. Of course angulation, inclination and other body movements come in to play to support and facilitate these actions, but as far as why a ski turns the above list is about all you need to know to teach skiing and to actually ski.
Quote:
Originally Posted by BigE

Skid angle:  It doesn't tell you why you turn.

What if we used it to describe how we turn instead and teach them to make use of it ?  I think it's practical application is clear in teaching skiers before carving becomes an option for them.

It's a different term in my mind because of a different focus. As simple as the difference between how and why    I can see using either while not intending to mean the exact same thing.
Teaching a carve is really easy. Easier than teaching skidding. It only involves tipping whereas skidding includes tipping and steering. The big problem with a carve is that carves on normal skis generally result in too much speed because the natural radius is so large.

I just taught a never ever, 6'1" 150lbs., starting on a 130cm ski (late 90's Rossi Development Cut). They make very small carved turns. She was making controlled linked carved turns before she made skidded turns. With just one thing to learn, tip the ski, it is instant success. I then showed her how she could let the ski skid to control the turns and control speed. I also taught her to let the ski flatten so that it would find the fall line. In two hours, she was skiing, on her own, in complete control. She could really ski.

Knowing why the turn happens isn't necessary, especially with beginners, just the how will make it happen.
You are correct MR.  However, as an instructor, you need to know why before you can properly teach how.  I am glad we are finally talking about the how, but don't disregard the why.  Remember this debate got started because some implied that steering could be seperated from skidding,  Some people said hogwash to that and off we went.

So the question remains, can steering be seperated from skidding and if so, how is that accomplished.
Edited by borntoski683 - 11/25/09 at 1:22pm
Steering will cause skidding regardless to what degree. There is no perfect turn and I just stay with that.
The only time you can separate it when you go straight or very slow and cautiously demo a carved "half" turn out of the fall line and ride the edge of the ski without influencing the radius.
What is your definition of steering then Simplyfast?

What do you call the technique where you use fore-aft balance to influence which part of the ski is being loaded?  Do you not think its possible to influence a carve by using fore-aft balance, by tipping more, getting more bend out of the shovel, etc?
The word "carve" I think should or can be in place for skidding. Technically to me there is no human out there that can carve a turn, it is all just a skid.

But I understand your point and you are right with what you say as much as BigE. I think you need to find a line or a rule of clarification, nobody needs to agree with mine, but it makes it more simple for me.

And all what you describe are good techniques to influence the outcome of that skid. I am not sure if I can help you much more.
Quote:
Originally Posted by borntoski683

You are correct MR.  However, as an instructor, you need to know why before you can properly teach how.  I am glad we are finally talking about the how, but don't disregard the how why (<-- is this change what you intended?).

I agree the why is important for a teacher. (I was pretty underimpressed when I took my Level 1 Certification by how little people understood skiing as well as their ability to demonstrate it that actually passed.) However the why provided in the previous pages seems way overboard.

The ski turns the skier because the resistance of the ski in and on the snow transfers some of  the momentum of the skier into another direction.

Resistance is provided by manipulating the ski. The ski creates resistance because when on edge, the edge penetrates the snow forming a trough. The momentum of the skier tries to move the ski along with it, however, the tip can channel some of the energy from the skier's momentum in the direction of the trough as the path of least resistance. With more centrifugal force or edge angle, the ski decambers, reshaping the trough and cause an arc of a different shape that can be further utilized to control turn size based on pressure and edge angle. The trough that the edge and the base create in the snow resists the movement of the skier and redirects the energy. If resistance is through purely cutting and displacing (or compressing) the snow in its curved path, we have carving and a very efficient redirection of energy. When the ski  doesn't create a trough with sufficient integrity to withstand the centrifugal force or the ski is rotated, in addition to being tipped, the ski will not stay in or create the trough and will push snow, creating resistance. This redirects some energy to change the direction of the skier into we have skidding. It also transfers some energy to the loose snow it is pushing, so the energy transfer is less efficient and we have lower speeds than carving.

Skiing is a beautiful sport. It is also extremely dynamic. Using math and physics to the level of developing equations to define it is fantastic although in very limited circumstances may have benefits. Skiing relies on a few simple movements. The combination of these movements creates a myriad of possibilities and levels of complexity.

Lay terms and a basic understanding of resistance, momentum, how forces can be applied and utilized by skis should be sufficient to education for a teacher to instruct with.

Quote:
Remember this debate got started because some implied that steering could be separated from skidding,  Some people said hogwash to that and off we went.

So the question remains, can steering be separated from skidding and if so, how is that accomplished.

You can apply steering forces without achieving steering. You risk twisting out of your binding, though. If you are going to apply steering forces, you should be doing it to achieve a skidded turn. If not, you are just twisting your leg against a lever in a trough that isn't going to give until either your binding releases, your knee gives out or your skis begin to skid. When you apply steering forces you don't want to do it without making allowances for your ski to skid such as decreased edge angle relative to what would cause a carved turn.

You can't be steering without skidding.

FWIW, I haven't paid close attention to this conversation since about page one, other than to have checked back in repeatedly as I was curious to the answers to the four questions. I could not fathom the detail provided or complexity of the discussion. I didn't know precisely why it had taken this course and had little interest in the determination of the accuracy of the math and physics. I didn't see how it applied in a practical way to skiing and ski instruction.

I just picked up The Skier's Edge from the library and opened right to steering angle. I'll be educating myself as time goes on from that.

MR
Quote:
Originally Posted by simplyfast

The word "carve" I think should or can be in place for skidding. Technically to me there is no human out there that can carve a turn, it is all just a skid.

A carve is when the tip, the waist and the tail of a ski follow the same path in the snow, so that all the parts of the ski's edge pass through a single point sequentially.

A skid is when the tip, waist and tail don't follow through the same point in the snow.

Does that accurately reflect your definitions of carve and skid?
MR, thanks for the catch on my typo.  its been fixed now..

Quote:

I agree the why is important for a teacher. (I was pretty underimpressed when I took my Level 1 Certification by how little people understood skiing as well as their ability to demonstrate it that actually passed.) However the why provided in the previous pages seems way overboard.

As of yet, I claim a true WHY has not really been clearly provided because there was nothing but dissenting opinion.

Quote:
The ski turns the skier because the resistance of the ski in and on the snow transfers some of  the momentum of the skier into another direction.

Indeed

Quote:

Skiing is a beautiful sport. It is also extremely dynamic. Using math and physics to the level of developing equations to define it is fantastic although in very limited circumstances may have benefits. Skiing relies on a few simple movements. The combination of these movements creates a myriad of possibilities and levels of complexity.

I totally agree about the math.  I also agree that fine skiing requires very fine control of the nuance possible from the levels of complexity that are possible.  There are few people out there that really understand these things enough to even talk about it at all.  Most rad skiers just combine various skills and attain a certain proficiency by trial and error and feel.

Quote:

Lay terms and a basic understanding of resistance, momentum, how forces can be applied and utilized by skis should be sufficient to education for a teacher to instruct with.

Not "should be".  IT IS enough to teach with.  And a teacher should usually avoid even talking about terms like CoM and BoS with students.  However, that depends that the instructor got their information from a knowledgeable source that knows what they are talking about.  Sooner or later, there has to be a grand guru that understands why things work the way they do so that the simplified instruction being handed to students is actually in line with reality in terms of how skis work.  This is not rocket science.  In fact trying to make it into rocket science is why many on this forum get twisted around upside down about how skiing actually works.

This thread started with some simple questions about steering.  what happened after that is that people started questioning the science and asking what I consider to be stupid questions....and all kaos broke loose with junk science aplenty.  I would like to hope we can get back on track and actually talk about the how.  But if you prefer to think of skiing more altruistically without such understanding of it, that is certainly your right and privelage and this is not the thread for you.

Quote:
You can apply steering forces without achieving steering. You risk twisting out of your binding, though. If you are going to apply steering forces, you should be doing it to achieve a skidded turn. If not, you are just twisting your leg against a lever in a trough that isn't going to give until either your binding releases, your knee gives out or your skis begin to skid. When you apply steering forces you don't want to do it without making allowances for your ski to skid such as decreased edge angle relative to what would cause a carved turn.

You can't be steering without skidding.

By this I take it that your definition of "steering" is twisting.  My definition is not that.  My definition of steering is to change the path of the ski to something other than the park and ride radius it would be on otherwise.  This can be accomplished by manipulating the way the sidecut interacts, without any skidding at all.  In my world, steering does not neccessarily mean skidding, though it might.  And skidding can often not include any steering either.

This is why this thread should have been interesting to you MR.  :-)  Think about steering angle and how you can manipulate it without twisting your skis into a skid.  You can adjust fore-aft balance, you can tip more.  Both of these aspects of "steering" manipulate the steering angle by manging to increase the bend of the ski so as to steer the skis.  Twisting is just another component that can be brought into steering as well.

(SIDENOTE - for the record, when discussing steering in his latest book, LeMaster never once suggested that twisting was useful for steering skis mid-turn.  He talks about twisting them to establish a pivot entry to the turn, to establish a larger steering angle to begin the turn, but the various methods he later discusses for actually "steering" turns does not include twisting...for whatever that is worth)

Quote:
Originally Posted by MastersRacer
I just picked up The Skier's Edge from the library and opened right to steering angle. I'll be educating myself as time goes on from that.

GREAT.  The latest book is even more clear on the subject as he breaks down more about what happens when the ski is bent and why steering angle from bending is different from steering angle due to the ski being fanned out.
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