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# 4 Questions - Page 5

Yes, LeMaster does say that the steering effect changes to a braking effect, but please, don't think this is like flicking a switch.   The two items, skidding and braking are solidly intertwined.  It is better to say that the steering effects dominate the braking effects with increasing steering angle, after which braking will dominate steering .

LeMaster also says that the notion of the pure carve is just theorectical, meaning that in a pure carve there is a MINIMUM of braking effect, not an absence of it.

As we all know, the more you deviate from a "pure carve" the slower you will ski, and that's due to the braking effect that is ALWAYS present.
The two concepts can be used to explain how increasing the steering angle beyond a certain point results in less turning; as the demands of the greater steering become too great for the edge angle to deliver, the skid angle increases.
Quote:
Originally Posted by BigE

Yes, LeMaster does say that the steering effect changes to a braking effect, but please, don't think this is like flicking a switch.   The two items, skidding and braking are solidly intertwined.  It is better to say that the steering effects dominate the braking effects with increasing steering angle, after which braking will dominate steering .

LeMaster also says that the notion of the pure carve is just theorectical, meaning that in a pure carve there is a MINIMUM of braking effect, not an absence of it.

I would go along with BigE's clarity on this as he's described it above.

There is a thing we might call 'Steering Angle' and some may choose to convert to calling it a 'Skid Angle' beyond some preferential angle - but that's really fuzzy at best, convoluted at worst.  There is no meaningful cusp/inflection point in the progressive change from clean carving to pure sideways skidding where we can pin down a meaningful transition and where a change in terms is necessary.  To suggest we should "teach the difference" between the two presupposes there is a meaningful difference.  What exactly is the difference (other than perception)?

Rick,
If you really believe there's a meaningful difference between Steering Angle and Skid Angle then maybe you can provide a comparative Steering_Angle drawing to go along with the Skid_Angle drawing you've linked to above..?   Something that clearly shows the geometric/mechanical/physical difference between the two?

.ma
Edited by michaelA - 11/6/09 at 9:53pm
Quote:
Originally Posted by Skidude72

Well I find it hard to beleive you deliberatley misquoted LeMaster to simply bait me

You're right.  I have absolutely no interest in playing baiting games with you, skidude.  I truly don't have the time to waste on such foolishness.

Quote:
I find it hilarious that you knew of the "second part" and conviently chose to leave it out...when it is the part the completly negates your entire arugment.  Keep on truckin Rick!

You need to go back and read what I wrote again about the second part of his steering angle explanation and how it compares to skid angle.  It doesn't negate a thing I said.  To the contrary it actually reinforces what I said.  I clearly explained that.

And this is not an argument.  There are many ways to build a house, and there are many angles to come at this ski instruction thing. Great skiers get developed around the globe via many different teaching methodologies.  LeMaster is a smart guy who has made valuable contributions to the sport of skiing.  That said, other perspectives and methodologies do exist in the world of ski instruction.  New ideas will emerge as the sport and teaching evolves.  New models have and will continue to be built.  Those who are willing and able to think outside of the established box will be the innovators of the future, as well as the teaches who remain ahead of the curve.

This thread was actually intended to discuss rotational states, and their influence on turns and initiations, but it's evolving into a window into a different perspective and way of developing and employing edging skills.  i can tell you from experience that this package of skills produces amazing improvement results.  They provide learning students with great confidence and control, and big resultant smiles. For those interested in hearing more about it I'm willing to share.  For others like yourself, skidude, who seem to be determined to call it bunk, it would probably make more sense to not waste their time with it and just move on.
Quote:
Originally Posted by michaelA

Rick,
If you really believe there's a meaningful difference between Steering Angle and Skid Angle then maybe you can provide a comparative Steering_Angle drawing to go along with the Skid_Angle drawing you've linked to above..?   Something that clearly shows the geometric/mechanical/physical difference between the two?

.ma

Michael, the two, steering angle and skid angle will look similar on paper in a moment in time.  They both are defined by a angular divergence between the direction of travel and the direction the skis point.  The real difference between the two concepts is in the influence those angles have on the performance of the skis, and in how the skier can put them to use.

Ron up to a point labels them a dictator of turn shape, then after that point a monitor of speed.

I use skid angle primarily as a speed management tool.  It does not necessarily dictate the sharpening of turn shape at lower angles, nor does it restrict it at higher angles.  The skier has complete control over each aspect independently.  Therein lies the power of the approach.
Since Rick is too busy bickering with skidude, here's an example for you Michael.
You're carving nice rail-road tracks along a path that has a turn with an apex having about a 5 m radius.  There is significant steering angle and skid angle = 0.0 degrees.

Now onto more interesting things.
Level 1 steering applying torque directly to the ski to change the steering angle.
Level 2 steering applying a force or combination of forces or combination of forces and torques to the ski so that the snow applies  greater forces and torque to the ski to alter the steering angle.

You can pivot an edged ski on hardpack, just in the plane of the snow surface, not in the plane of the ski, and it's much harder to do with level 1 steering than it is with level 2 steering.

More interesting still, how to distinguish steering from "carving" or "arcing".  We can distinguish pivoting from carving pure arc pencil thin lines on the hardpack with 0 skid angle (for Ron LeMaster devotees lets say 0 degrees 0 minutes and a few seconds is pure enough), but pivoting is only one means of steering.

Is there a difference?  Some people see a difference.  What is it that gives rise to this perception?  Can it be better explained?  Is it that steering is a means of altering a skid angle and carving is not?  If your skiing is based on shaping the ski and then using the skis edge with as close to 0 skid angle as possible, is the shaping of the ski steering?  even if it involves no pivoting or skidding?

Edit: I type slow.
Quote:
Originally Posted by Rick

And this is not an argument.  There are many ways to build a house, and there are many angles to come at this ski instruction thing. Great skiers get developed around the globe via many different teaching methodologies.  LeMaster is a smart guy who has made valuable contributions to the sport of skiing.  That said, other perspectives and methodologies do exist in the world of ski instruction.  New ideas will emerge as the sport and teaching evolves.  New models have and will continue to be built.  Those who are willing and able to think outside of the established box will be the innovators of the future, as well as the teaches who remain ahead of the curve.

This thread was actually intended to discuss rotational states, and their influence on turns and initiations, but it's evolving into a window into a different perspective and way of developing and employing edging skills.  i can tell you from experience that this package of skills produces amazing improvement results.  They provide learning students with great confidence and control, and big resultant smiles. For those interested in hearing more about it I'm willing to share.  For others like yourself, skidude, who seem to be determined to call it bunk, it would probably make more sense to not waste their time with it and just move on.

If you have somthing new Rick, please offer it.  Myself and others here would love to read about it.  My only issue was with your misrepresentation of Lemaster.

I think below sums up both our views quiet nicely.

Quote:
Originally Posted by Rick

Michael, the two, steering angle and skid angle will look similar on paper in a moment in time.  They both are defined by a angular divergence between the direction of travel and the direction the skis point.  The real difference between the two concepts is in the influence those angles have on the performance of the skis, and in how the skier can put them to use.

So they look the same...defined the same...but yet...according to you are different...lets explore that shall we?

Originally Posted by Rick

Ron up to a point labels them a dictator of turn shape, then after that point a monitor of speed.

BULL!  Please please please read his work.  Understand it.  Then profess what you know.  Ron says it dictates shape and speed....or just one, or the other....just like you are.........
Originally Posted by Rick

I use skid angle primarily as a speed management tool.  It does not necessarily dictate the sharpening of turn shape at lower angles, nor does it restrict it at higher angles.  The skier has complete control over each aspect independently.  Therein lies the power of the approach.

Ron and everbody else makes the exact same point......nothing new Richard.  Nothing new.

I am happy for you to discuss this concept....but please stop discrediting others to make it out like you have invented somthing new or grand...you havent.
Thanks Ghost, but if that's Skid Angle, then I'm still not clear on what Steering Angle would be in the scenario you describe.  The 5m-radius carving skier you describe has a Skid-Angle of 0.0-degrees... OK, let's say that's true since they're not "skidding" at all. In that exact situation, what exactly is their Steering-Angle as measured in Degrees at that moment?

As I currently see things, that angle is also exactly 0.0 Degrees since both angles are exactly the same concept, just presented from different preferential interpretations.  This is a bit like trying to describe Carving vs. Scarving - exactly where does one become the other?  Is it at 0.025 degrees of tracking variation?  At 0.25 degrees?  Maybe 2.5 degrees if we're in soft snow?

Quote:
Originally Posted by Rick

Michael, the two, steering angle and skid angle will look similar on paper in a moment in time.  They both are defined by a angular divergence between the direction of travel and the direction the skis point.  The real difference between the two concepts is in the influence those angles have on the performance of the skis, and in how the skier can put them to use.

In this paragraph you cite that 'both angles are the same' ... but then you go on to say the two concepts differ in the influence those "two angles" (which are appear to be exactly the same at all times) have on performance of the skis.  These two statements seem to contradict each other.

If both angles are always exactly the same (unless you can draw a example where they're shown to be different) then how can each ever have a different influence (than the other angle) on the performance of our skis?

If this is just a perspective thing (wanting simply to say "Skidding Direction" rather than provide a more technically accurate description) then it might make sense as more simplistic terms go over better with kids.  If you genuinely believe there's a mechanically unique principle here, it would help to better differentiate the proposed difference.

.ma
The steering angle defined above uses the direction the skis tips are pointing in.  If you take a moment and look with your minds eye down on the plane of the surface of the snow in our little example of a 5-m turn, you will realize that the ski is not straight, but is curved into a curve with a radius of 5 m,  Say you have a Slalom ski with about a meter of ski ahead of the boot centre.  Your ski tip will point about 11.5 degrees from your direction of travel.  Steering angle = 11.5, skid angle = 0.  11.5 is not equal to 0.  Q.E.D.  Different.

I think steering angle must have started because thrust angle is just too complicated and abstract a concept for your run of the mill student compared with the direction your ski tips are pointing. (direction of net force acting on skier)  EDIT: I take that back.  The direction your skis are pointing has merit in its own right.
Quote:
Originally Posted by michaelA

....you cite that 'both angles are the same' ... but then you go on to say the two concepts differ in the influence those "two angles" (which are appear to be exactly the same at all times) have on performance of the skis.  These two statements seem to contradict each other.

No, the two statements don't contradict each other,,, the concepts contradict each other.  That's what I've tried to explain.

Here are two statements straight out of LeMaster's fingers;

1) "A small steering angle results in a broad turn".

2) "A larger steering angle, up to a point, produces a sharper turn".

Those are two absolute statements that apparently reflect Ron's perception of how steering/skid angle influence a turn.  They don't reflect mine.  I recognize broader options than that, and my teachng methodology puts those broader options to good use.

Yes, a small steering/skid angle CAN result in a broad turn, but it doesn't have to.  In reality, no such radius limitations exist.

And a larger steering angle (those up to that arbitrary point he speaks of, where ever it may lie) does not necessarily produce a sharper turn.  It can do that, but it can also produce a longer radius turn.

In my teaching specific steering/skid angles to not carry the radius limitations Ron seems to envision as evidenced by his above statements.  As I've said, any steering/skid angle can in reality produce any radius the skier desires.  These broader possibilities provide my students many more turn shape/speed options.  Those broader options, once learned, provide great advantages to the learning skier.

The reason I chose to use skid angle is because it better reflects what it actually does.  As I've just explained, it has little to do with radius control.  Radius control is separately managed.  Skid angle is our speed control mechanism.  The bigger the skid angle, the more the skis skid, so the slower the speed of travel.  Radius control comes through other edge control applications.
Ok Rick...to end the bickering, as you will clearly never admit to being wrong....lets move on.

So I'll bite on this little gem:

Quote:
Originally Posted by Rick

Yes, a small steering/skid angle CAN result in a broad turn, but it doesn't have to.  In reality, no such radius limitations exist.

Care to explain how to tighten a turn without increasing steering angle?  And I use the term steering angle deliberatley.  Your wording above seems to indicate these terms are now interchangable.

Psst:  Rick's answer will likely be somthing along the lines of :   put the ski on its edge more, get it to flex more, which will drive the turn radius....but of course that is a bunk argument becuase bending the ski, by the steering angle definition means you are increasing steering angle...which Richard claims is not necessary....this should be good.
Ghost,

I'd considered that particular interpretation and dismissed it as being untenable because there simply isn't any reproducible integrity in that particular "angle measurement".   We'd be preferentially selecting a rather random point along a curve (the bent ski) then measuring the difference between the tangent at that particular point against some other directional vector and calling it the "defined" Steering Angle.

If we select a point 6 inches further back along the ski then our Steering Angle is a few degrees less.  If we arbitrarily select a point 20 inches back then our Steering Angle becomes even less.  And this is true regardless whether we are carving, scarving or primarily skidding.  It also fails as a definitive measure because as ski length gets longer, the angle measured gets larger (if measured at the tip).  There is also the problem with deciding whether we choose the centerline of the ski to measure against or the surface-contacting edge and any deviation caused by sidecut.

{  The instantaneous direction our skis are pointed (assuming a parallel stance and using the ski's centerline under the boot) vs. the instantaneous direction they are actually traveling is my own definition for Steering Angle (aka: Drift angle; Skid Angle).   This definition seems highly reproducible.  }

---

Rick,

By the way you're now using the paired-up term "Steering/Skid Angle" you seem now to be acknowledging that the two terms are actually interchangeable as the same thing and that there really isn't any difference...  (I could certainly live with that and personally, I like the term 'Drift Angle' as well)

I don't believe for a minute Ron LeMaster envisioned any of the "radius limitations" you interpret from his text.  I suspect he was writing that material in a particular context and by printing isolated snippets here you're creating a false impression for what he was actually trying to communicate.   Since it's obvious to all of us here that edge-angle combined with Steering Angle can result in many different actual turn-radius outcomes, I suspect Ron probably knows it also and that it wouldn't be new information to him.

As I see it, turn radius is managed by a combination of edge-angle, ILS and pressure.  The resulting Steering/Skidding Angle is just the outcome of those three inputs (along with slope angle, snow conditions and current speed which we don't manage internally).  Would you agree with this?

Also, when you say, "Any skid angle can be combined with any turn radius"... Wouldn't you agree that this is highly dependent on slope angle and/or speed?   For instance, there's no way to maintain a large Steering Angle *and* a large turn radius unless you've a lot of speed or a reasonable slope-angle to keep you going.  'Course, you could try to keep those skis extremely flat - and hope you don't catch an edge... (Context is everything )

I would agree that Steering/Skid Angle does figure into the amount of friction (braking) we produce - but so does edge-angle and pressure (again, as modified by slope angle, snow conditions and speed).

.ma
Now Skidude ...

( restrain yourself  )

.ma
Quote:
Originally Posted by michaelA

Also, when you say, "Any skid angle can be combined with any turn radius"... Wouldn't you agree that this is highly dependent on slope angle and/or speed?   For instance, there's no way to maintain a large Steering Angle *and* a large turn radius unless you've a lot of speed or a reasonable slope-angle to keep you going.  'Course, you could try to keep those skis extremely flat - and hope you don't catch an edge.

(Sorry I'm late to the party)

ma., you gave yourself the answer in your own post.  "you could try to keep those skis extremely flat - and hope you don't catch and edge."

If you think of the steering (rotational movement of the foot/leg or both) as a passive one once the turn has started and back off the edges and pressure (or increase either or both) you should be able to produce almost any radius you want (assuming there is enough speed and hill and it's in ones ability level) at any speed.

I'm can easily see a very large radius being accomplished on a relatively flat hill at a low rate of speed with a lot of constant skid angle.

(I'm going to say it before the faithful do.....it's a brushed carve)

A quick side note on the pelvis being able to stay square and steering w/o rotation of the femur.  PSIA, at one point (and maybe still), recognized "foot steering" as a way to "turn" the ski.  It's possible to steer the foot and while the femur may move in the hip socket, it doesn't have to rotate.  Lower level move, but shows that it is possible to "steer" and remain "square" (or not!!!)
Quote:
Originally Posted by michaelA

Ghost,

I'd considered that particular interpretation and dismissed it as being untenable because there simply isn't any reproducible integrity in that particular "angle measurement".   We'd be preferentially selecting a rather random point along a curve (the bent ski) then measuring the difference between the tangent at that particular point against some other directional vector and calling it the "defined" Steering Angle.

If we select a point 6 inches further back along the ski then our Steering Angle is a few degrees less.  If we arbitrarily select a point 20 inches back then our Steering Angle becomes even less.  And this is true regardless whether we are carving, scarving or primarily skidding.  It also fails as a definitive measure because as ski length gets longer, the angle measured gets larger (if measured at the tip).  There is also the problem with deciding whether we choose the centerline of the ski to measure against or the surface-contacting edge and any deviation caused by sidecut.

{  The instantaneous direction our skis are pointed (assuming a parallel stance and using the ski's centerline under the boot) vs. the instantaneous direction they are actually traveling is my own definition for Steering Angle (aka: Drift angle; Skid Angle).   This definition seems highly reproducible.  }
Yes, Michael, I realize that, in fact if you read post 110, I made the same complaints about steering angle as it was defined for me before that post.

Quote:
Originally Posted by Ghost
A typical ski in a typical turn is decambered and thus curved.  Skid angle can vary along the edge of a ski, an over-all averaged (integrated if your mathematically inclined) skid angle can be used.  Steering angle as you folks have described it, would depend on how long my skis are for any given arc, and "the direction I would end up going" depends on how long I keep turning just as much as it depends on how hard I happen to be turning at the moment.  What's more, though related, the direction the skis are pointing in is not the direction that the forces acting on the ski are trying to push me in; there is a significant sideways component.
(actually most of the force is directed 90 degrees to the edge)

However I was very careful to get it fully defined before using "steering angle" in an argument.  If you read Skidude72's reply to me, you will see that the term is (perhaps arbitrarily) defined to be taken from the tip, not from the midsection, not the tail, not 6" back from the tip.  At least it is a consistent term for any given pair of skis.
Quote:
Originally Posted by Skidude72

In a pure skidded turn the steering angle is rather obvious and intuitive, it is simply the difference between where our skis are pointing and the direction we are moving at any given instant in time.

In a pure carved turn the steering angle is still there, but perhaps not as obvious.  The steering angle in a pure carved turn is the difference between where our ski tips are pointing and where the ski under foot is pointing.  Why the ski tip?  Because in a pure carved turn the tip is leading the turn, the ski underfoot will follow.
Your definition is so good that it is a describes a term that needs defining.  Only problem is, steering angle is already taken.  Let's call it skid angle, and while were at it, let's apply it to the direction of travel of the edge at any point on the edge and compare it to the direction that part of the edge is pointing,  That way we can apply it to curving skis and talk about differing skid angles at different parts of the ski.

If you were to define steering angle at midboot, and not at the tip then the steering angle would be the same as the skid angle and steering angle would be 0 for a carved pure arc, and the two statements above referred to as LaMaster's 1) and 2) would not be correct.  However the term seems to be already defined for us, so we cannot make up our own definitions.  That's a good thing, because we now have two different concepts to explain what's happening on the hill.  Steering angle adjustment (steering) and skid angle adjustment (strength of edge grip if you prefer).  Bigger steering angle with greater skid angle could turn the same as lower steering angle and lower skid angle.  However you still need a steering angle to turn, and a bigger one to make a harder turn.

Rick, I don't think you can make a small radius turn with a low steering angle. Think about where's the turning force is coming from and in which direction it is pointing with a low steering angle.
Edited by Ghost - 11/7/09 at 5:00am
Quote:
Originally Posted by Rick
In my teaching specific skid angles do not carry the radius limitations of the term steering angle, as used by Ron.  As I've said, any steering/skid angle can in reality produce any radius the skier desires.  These broader possibilities provide my students many more turn shape/speed options.  Those broader options, once learned, provide great advantages to the learning skier.
Fixed it for you.
Now that that's all settled .

Let's define steering as opposed to carving without steering.  What's the defining difference between a steered turn and a carved turn?  (let's save carving until we're a little better at this nailing definitions down thing)
What's wrong with

"Steering is setting the steering angle using any method that does not have the skis simply move forward in the direction parallel to their (curved into whatever shape you like) edges into the new steering direction with zero skid angle."
Quote:
Originally Posted by michaelA

Rick,

By the way you're now using the paired-up term "Steering/Skid Angle" you seem now to be acknowledging that the two terms are actually interchangeable as the same thing and that there really isn't any difference...  (I could certainly live with that and personally, I like the term 'Drift Angle' as well)

For the most part they are, in terms of what the angle of the ski compared to the direction of skier movement looks like.  I define that angle as created under foot, and Ron seems to also when he says, "the middle of the ski does the work of changing your direction of travel, largely due to its steering angle there."

Where I differ in my use of the skid angle term is that I don't move my point of reference when we get into carving.  I still focus on what's happening underfoot, and how much skid the ski is producing.  In the case of carving that skid angle obviously would be zero.  Ron also looks at steering angles in the forebody of the ski caused by the ski's "self steering effect".  While he's perfectly accurate in his explanation of that "effect", the multiple reference points for his steering angle term adds a bit of complexity that I'm able and happy to avoid.

My linking of the two terms was from the context of his under foot focus, and with the purpose of pointing out how our concepts of the primary applications of those skid/steer angles differ.

Quote:
I don't believe for a minute Ron LeMaster envisioned any of the "radius limitations" you interpret from his text.  I suspect he was writing that material in a particular context and by printing isolated snippets here you're creating a false impression for what he was actually trying to communicate.   Since it's obvious to all of us here that edge-angle combined with Steering Angle can result in many different actual turn-radius outcomes, I suspect Ron probably knows it also and that it wouldn't be new information to him.

Actually, Michael, all the way through his explanation, which only constitutes a couple pages, he consistently has a theme of linking steering angle to resultant radius.  No where does he really discuss options for delinking the two, or even that such options exist.  Whether or not he understands this, we can only speculate what lurks in his head, because it does not live in the book.  Like you, I too suspect he's aware of it, but does that really matter?  At this point all we can do is deal with and compare to what he has put in print.

And really, Ron LeMaster and his beliefs are not what this thread is about.  He simply came up because a term exists that's very close in nature to one I use, and we needed a definition of it so I could explain why I chose not to go with it.

Quote:
As I see it, turn radius is managed by a combination of edge-angle, ILS and pressure.  The resulting Steering/Skidding Angle is just the outcome of those three inputs (along with slope angle, snow conditions and current speed which we don't manage internally).  Would you agree with this?

Yes, absoulutely.  And it's the options we have to mix and match the amount and nature of the edge, steering and pressure we use that provides us the ablity to greatly delink radius from skid angle.

Quote:
Also, when you say, "Any skid angle can be combined with any turn radius"... Wouldn't you agree that this is highly dependent on slope angle and/or speed?   For instance, there's no way to maintain a large Steering Angle *and* a large turn radius unless you've a lot of speed or a reasonable slope-angle to keep you going.

Of course.  There will be a limit to how flat a slope that an ultra large skid angle will allow you to remain in motion.  It does, after all have the potential to produce a large amount of drag, which is the point of it.

It's actually a great training exercise to see how big of an skid angle you can employ on a flat slope,,, super for developing fine edge control, but in reality such a slope is not where a large skid angle is going have it's most useful application.  It's designed to provide speed control with in a specific turn shape.  On on a steeper pitch it allows students to learn good turn shape within a personal comfort zone.  That's where this particular radius/skid combo really shines.

Quote:
I would agree that Steering/Skid Angle does figure into the amount of friction (braking) we produce - but so does edge-angle and pressure (again, as modified by slope angle, snow conditions and speed).

It's all part of the equation.  Turn shape,,, degree of turn,,, they too are very useful speed managment tools.  But they will never touch the versatility and pay back potential of skid angle when it comes to speed management options.
Edited by Rick - 11/7/09 at 11:30am
Quote:
Originally Posted by Ghost

Fixed it for you.

Thanks Ghost.  Can we now move on?  I doubt it.  Although I may.  The lifts are running out here.  Time to do this for real.
The thing I have more a problem with is not the ability to create a large radius turn with any skid angle.  Its the smaller radius turns with any skid angle.  At speed that isn't going to happen as the speed will turn almost any amount of steering angle into skid angle.  The tightest radius turns at speed will be carved with very little if any skid angle, otherwise the radius will expand.
Quote:
Originally Posted by Rick

For the most part they are, in terms of what the angle of the ski compared to the direction of skier movement looks like.  I define that angle as created under foot, and Ron seems to also when he says, "the middle of the ski does the work of changing your direction of travel, largely due to its steering angle there."

Where I differ in my use of the skid angle term is that I don't move my point of reference when we get into carving.

Actually the full quote is:

"the middle of the ski does the work of changing your direction of travel, largely due to its steering angle there, as shown in figure 3.6a."

Now figure 3.6a shows very clearly what he means....

In a nut shell it is:

Before you can turn, the skis must turn.  Hence step one is to turn the skis, step two is the skis then act to turn you.  The only part of the ski capable of turning you, is the middle...the tip and tail only turn the ski....

EDIT: It also clearly shows that the steering angle is the difference between the skiers direction of travel and the direction the skis are pointing, in this specific example that Rick is quoting the ski direction under foot is the same as the tip direction....no multiple refrence points...(the diagram clearly and simply shows this..it is just a ski with 2 lines) ...key to the steering angle concept is the idea of first turning the skis, then the skis turn the skier...thus it is important to distinquish which phase is being discussed the ski turning, or the the skier turning.

"Points of reference" have nothing to do with it.

Quote:
Originally Posted by Rick

Where I differ in my use of the skid angle term is that I don't move my point of reference when we get into carving.  I still focus on what's happening underfoot, and how much skid the ski is producing.  In the case of carving that skid angle obviously would be zero.  Ron also looks at steering angles in the forebody of the ski caused by the ski's "self steering effect".  While he's perfectly accurate in his explanation of that "effect", the multiple reference points for his steering angle term adds a bit of complexity that I'm able and happy to avoid.

Again there are not multipe reference points in his work.

Quote:
Originally Posted by Rick

Actually, Michael, all the way through his explanation, which only constitutes a couple pages, he consistently has a theme of linking steering angle to resultant radius.  No where does he really discuss options for delinking the two, or even that such options exist.  Whether or not he understands this, we can only speculate what lurks in his head, because it does not live in the book.  Like you, I too suspect he's aware of it, but does that really matter?  At this point all we can do is deal with and compare to what he has put in print.

Well this is where you are wrong.  Remember Steering Angle is ONE concept.  The amount of steering angle you have combined with edging and fore/aft balance will dictate turn shape and or speed control.  The reason he does not discuss the options for delinking the two...is because in reality the ARENT ANY!!!!!!!!!!!!!!!!!!!!!

Now there is a statment.

Disagree?

Please explain these two basic scenarios then:

Quote:
Originally Posted by Rick

Yes, a small steering/skid angle CAN result in a broad turn, but it doesn't have to.  In reality, no such radius limitations exist.

How is this possible?  How can you tighten turn radius without increasing steering angle? Again, as I asked above....any answer pointing out that you can tip the ski more to get it to bend are negated because bending the ski is increasing steering angle....others have asked you this same question.

Second question:

How do you have a big steering angle, long turn...WITHOUT speed reduction??????????????????????

My view is you cant.  The two are completley linked, you simply cannot separate these things as you suggest.

EDIT 2: What is possible is to add a slowing component to any turn shape....by overdoing the steering angle.  As clearly stated by myself, Ron and countless others...but that is it...still fundamental to steering angle.

Ron Lemaster:  "A large steering angle, up to a point, produces a sharper turn.  Beyond that point, increases in thhe steering angle cause more slowing, but less turning."

You seem to suggest that there is a lot more options available....please educate us.  But please start by answering my and others 2 questions above...they are simple, direct, unamibigous and relevant.

Edited by Skidude72 - 11/7/09 at 3:05pm
Quote:
Originally Posted by borntoski683

The thing I have more a problem with is not the ability to create a large radius turn with any skid angle.  Its the smaller radius turns with any skid angle.  At speed that isn't going to happen as the speed will turn almost any amount of steering angle into skid angle.  The tightest radius turns at speed will be carved with very little if any skid angle, otherwise the radius will expand.

Any steered turn will have a skid angle greater than 0, that's a given.  As you suggest, only a carved turn will have a 0 skid angle.  The important thing to understand with this is that as sharp a turn as you can carve, i can steer one much sharper, and while not with a skid angle of zero, I can do it with a very small skid angle, such that I leave a very narrow skid track in my wake.  I could also do that same turn with a very large skid angle, or any angle within those two extremes.  Those are the skid angle options of which I speak, and they extend to any radius of turn.

It's a shame we never got to a point where that could have been understood and accepted.  We could have then moved into discussing how those options can be used to enhance the learning experience of students.
Quote:
Originally Posted by Rick

Any steered turn will have a skid angle greater than 0, that's a given.  As you suggest, only a carved turn will have a 0 skid angle.  The important thing to understand with this is that as sharp a turn as you can carve, i can steer one much sharper, and while not with a skid angle of zero, I can do it with a very small skid angle, such that I leave a very narrow skid track in my wake. Translation: I can increase the steering angle beyond what is derived from purley a bent ski by adding a pivoting effort to tighten the turn (which is exactley what I said you would say)..... I could also do that same turn with a very large skid angle Which would result in a greater slowing effect...also clearly stated by others, or any angle within those two extremes.  Those are the skid angle options of which I speak, and they extend to any radius of turn.

It's a shame we never got to a point where that could have been understood and accepted.  We could have then moved into discussing how those options can be used to enhance the learning experience of students.

Well if that is all you are claiming....no issues.  That is after all exactley what the steering angle concept tells us.  So I guess on one hand no need to worry or feel shame, because I think it is fair to say that is well understood and accepted.

What we dont understand Rick is all those other options that are unique to your theory.  Answering the the two questions in post #141 would be a good start.
I defy you to make a 5 m turn with a steering angle of 1 degree.  Skid angle of 1 degree, no problem.  Steering angle of 1 degree?  Ain't gonna happen.
Quote:
Originally Posted by Ghost

I defy you to make a 5 m turn with a steering angle of 1 degree.  Skid angle of 1 degree, no problem.  Steering angle of 1 degree?  Ain't gonna happen.

Right, ghost.  You've got it.

Steering angle as measured at the tip of the ski for a 5 meter carved turn on a 165 ski would be in the vicinity of 10 degrees (quick top of the head calculation, should be within  a degree).  Still small on the 0-90 scale, but not nearly as small as the comparative skid angle.
Well... this could be fun!

Rick,
Sounds like you've modified (through elaboration) some of the things I had disagreed with earlier such that most things you've now restated are well in line with my own take on things.  There is only one area in this I'd want to explore further, though mostly with Ghost as you seem dubious of that whole Steering Angle idea as it relates to carving (based on your non-committal reference to it above ).

Ghost,
Sorry - I didn't see your Post #110 referencing arcs and angles.  Had I seen it, I'd have quoted you and seconded the notion that there are distinct problems with using any point(s) along a bent ski to reference definitive angles of motion for our skier.

Below is a diagram that may help clarify my problems with it...

While not drawn perfectly to scale, I tried to highlight the different "Steering Angles" we would have to acknowledge at different points along the ski.  If we take only the midpoint directly underfoot we're left with 0.0-degrees for our Steering Angle on a carving ski.  To me this perspective makes sense as our carving skier is basically moving directly with the ski underfoot.

But... the moment we try to specify our Steering Angle based on a point anywhere else along the bent ski, we lose definitive meaning.   For instance, the slightly forward blue line shows a 10-degree Steering Angle.  If we choose "The Tip" as our definitive measuring location we end up with a "20-degree Steering Angle".   Great, but if the ski we're wearing is just a bit longer (dashed Tip outline) we end up with a "30-degree Steering Angle" for that scenario.

What's most interesting to me is that we're getting several different "Steering Angles" specified for the exact same skier carving exactly the same 10-foot radius turn!  If our ski were so long that the Tip reaches all the way to the other side of the drawn circle, wouldn't our Steering Angle now be 180-degrees?  Does that make any sense?

This is why we cannot use that particular definition - because however we do it, it's still an arbitrary selection point from which we create an arbitrary measurement number.   Further, regardless what number is produced (10, 20, 30 degrees) we're still carving exactly the same 10-foot radius turn as before, thus rendering any such measurement devoid of significance.  We get a bunch of different 'numbers' for exactly the same scenario.

When actually Carving (to perfection) our "Steering Angle" by any reasonable definition would always be 0.0-degrees.

Regrettably, I don't have those books by Ron LeMaster to read and interpret myself but I'd bet good money he would not have described Steering Angle as anything other than the direction difference between where the ski is 'pointing' (centerline underfoot) and actual direction of travel.  More or less carving (vs. skidding) is relevant to resulting direction but once we reach clean carving, Steering Angle is 0.0.

BTW: If we'd like to examine when "turning" gives way to "braking" as Steering Angle increases then I'd go with 45-degrees as the perfect transition point to throw that switch.  Once the ski is turned more than 45 degrees across the path of travel it will begin to produce more braking force than turning force (all else being equal).

.ma
michaelA,

Steering angle is zero only when you are moving straight down the fall line.

BigE,
That's open to question and is the whole point of the material presented above.

If a person is cleanly carving a turn ... then I propose that by legitimate definition they have a 0.0-degree Steering Angle  (plus or minus a very tiny amount).  I hold this position because there doesn't seem to be any credible argument to the contrary with respect to a carved turn. My post above attempts to show why previous definitions around the 'carving problem' are not really legitimate.

My specific concern with Steering Angle as related to carving is that there is no overall motion of the ski in any other direction than is being defined by the 'direction' the ski is pointed.  Attempts to 'pick' a preferential spot on the carving ski only results in an angle dictated by that selection rather than any genuine fundamental relationship.

If a bent ski (forming an arc on the snow) were drifting off the scribed carving pattern, then yes I'd agree we're back to some degree of Steering Angle being present - but not if that ski is holding its carve.

I'm wholly on board with Steering Angle reasoning related to skidding or partially 'scarved' turning because in those cases there is movement of the ski at some angle other than where the ski is "pointed" (a very loose term when carving - maybe "edge-tracking" would be a better term since it defines a clear pattern of motion along that grove).

.ma
Michael, what you're talking about is exactly what my skid angle refers to.  Now you're seeing why I adopted a different term.  Steering angle is harbored with definitions that just don't work for what I'm trying to describe.

LeMaster talks not only about steering angles under foot, but also about steering angles within various parts of the ski, including both tail and forebody.  Those were the other reference points I spoke of earlier.  So yes, by his description a carving ski has a built in steering angle.  It's not zero.  Skid angle would be 0.

You're right, the length of the ski alters the steering angle, even when the shape of the turn is exactly the same.  Quite confusing indeed. Ski length has no effect on skid angle when carving.  With skid angle carving is 0, period.

Interesting too, he has a term he uses for the steering angle created solely via the sidecut of the ski.  He calls it the "local steering angle". It harbors the same peculiarity you just recognized.  A longer ski with the exact same sidecut radius will have a larger local steering angle. Two skis that will produce the same turn shape, but have different local steering angles.
Edited by Rick - 11/7/09 at 11:58pm
Quote:
Originally Posted by michaelA

Well... this could be fun!

Rick,
Sounds like you've modified (through elaboration) some of the things I had disagreed with earlier such that most things you've now restated are well in line with my own take on things.  There is only one area in this I'd want to explore further, though mostly with Ghost as you seem dubious of that whole Steering Angle idea as it relates to carving (based on your non-committal reference to it above ).

Ghost,
Sorry - I didn't see your Post #110 referencing arcs and angles.  Had I seen it, I'd have quoted you and seconded the notion that there are distinct problems with using any point(s) along a bent ski to reference definitive angles of motion for our skier.

Below is a diagram that may help clarify my problems with it...

While not drawn perfectly to scale, I tried to highlight the different "Steering Angles" we would have to acknowledge at different points along the ski.  If we take only the midpoint directly underfoot we're left with 0.0-degrees for our Steering Angle on a carving ski.  To me this perspective makes sense as our carving skier is basically moving directly with the ski underfoot.

But... the moment we try to specify our Steering Angle based on a point anywhere else along the bent ski, we lose definitive meaning.   For instance, the slightly forward blue line shows a 10-degree Steering Angle.  If we choose "The Tip" as our definitive measuring location we end up with a "20-degree Steering Angle".   Great, but if the ski we're wearing is just a bit longer (dashed Tip outline) we end up with a "30-degree Steering Angle" for that scenario.

What's most interesting to me is that we're getting several different "Steering Angles" specified for the exact same skier carving exactly the same 10-foot radius turn!  If our ski were so long that the Tip reaches all the way to the other side of the drawn circle, wouldn't our Steering Angle now be 180-degrees?  Does that make any sense?

This is why we cannot use that particular definition - because however we do it, it's still an arbitrary selection point from which we create an arbitrary measurement number.   Further, regardless what number is produced (10, 20, 30 degrees) we're still carving exactly the same 10-foot radius turn as before, thus rendering any such measurement devoid of significance.  We get a bunch of different 'numbers' for exactly the same scenario.

When actually Carving (to perfection) our "Steering Angle" by any reasonable definition would always be 0.0-degrees.

Regrettably, I don't have those books by Ron LeMaster to read and interpret myself but I'd bet good money he would not have described Steering Angle as anything other than the direction difference between where the ski is 'pointing' (centerline underfoot) and actual direction of travel.  More or less carving (vs. skidding) is relevant to resulting direction but once we reach clean carving, Steering Angle is 0.0.

BTW: If we'd like to examine when "turning" gives way to "braking" as Steering Angle increases then I'd go with 45-degrees as the perfect transition point to throw that switch.  Once the ski is turned more than 45 degrees across the path of travel it will begin to produce more braking force than turning force (all else being equal).

.ma

Good work Micheal, I am glad to see you are putting substantial thought into this.

But here are few points that might help:

1:  Steering angle is concept used to help us understand how we as skiers are able to execute a turn.  It is not intended as measurment tool.  I do not understand the value of knowing if the angle is 20 degrees or 23 degrees, but perhaps you could share that.

2:  In pure carved turns steering angle is the difference between where we are travelling and the angle the ski is pointing.  Now generally this is accepted as the difference between the ski tips, and the ski underfoot.  As stated in an earlier post the ski tip is used becuase in a carved turn the ski's midbody will allways follow the tip....that is how you get the pencil line ski track.  A longer ski is simply further along the curve.  Again "steering angle" is not a measurment tool, but it does show that for a given steering angle, regardless of the ski length, we will get the same turn.

3.  In reality thou it is not as simple as described in my point 2.  The steering angle concept is about 2 stages.  Stage 1 the ski must turn.  Stage 2 the ski turns us.  Now in point two above that only talks about the ski turning.  To make the skier turn the ski underfoot does that, by acting at some angle accross our direction of travel.  In a carved turn, this again is not intuitive.  However our direction of travel is actually moving outside the arc....this is why we feel centripadel force...our mass wants to keep moving in a straight line, the turning ski beneath our feet prevents that.  That is why even in a pure carved turn the steering angle is not 0.

Happy to disucss.
Edited by Skidude72 - 11/8/09 at 2:54am
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