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# Skiing The Fast Line Slow - Page 5

CoM is not always moving in exactly the same direction as the boots are pointing.  For example during cross-over or cross under, CoM seems to the skier to be moving 90 degrees to the direction the boots are pointing; it's not actually 90 degrees, but it is far from zero degrees.  During apex, perhaps the angle is zero (in an arced turn).  It varies throughout the turn.

As to the direction a skier will travel after losing an edge, it is actually tangential, like the highschool pyhsics video releasing basketballs from a convertible on curve, but to the skier it seems to be radial, because they are accustomed to the turning frame of reference, just like it would feel like you were going off radially from a fast moving merry-go-round.

The problem is that the circular path of the skis is created by the deflection itself. It fundamentally has to happen first so the ski has to have some steering angle under foot. Even at the apex. Zero steering angle would be like letting the basketball go. Prior to letting the basketball go the hand holding it would need some kind of steering angle also.

Again the angle of momentum is not exactly tangent at the point of the feet, it's behind the feet. Sure when released it goes on a tangent, but not the direction the boots are pointing.

What happens at transition is also a tangent but its just intentionally released.
Quote:
Originally Posted by borntoski683

As to how you and your racer buddies were able to remain on the same turn radius while going airborne in a turn, I think you are mistaken as to what you were actually doing. As you like to remind us that was 40 years ago. B-)

One might think so, BTS, but live it and you'll understand why you don't forget it.

Something about coming up on a drop off at 80 mph, and about to launch over 100 feet, and the only thing that determines if you stay on course or head into the trees is the direction you're going at take off,,,, well,,, that kind of stuff just seems to stay deposited in the ole memory bank.

BTW; you don't stay on a turn radius when you disengage.  You stop turning and travel straight.  At least until something diverts your direction of travel again, such as your body slamming into the snow, bouncing off a tree, or a fence, etc, etc.

My explanation would be that you made sure to have adequate steering angle so that when you launch the tangential direction you fly is the direction you want to go. If you are truly mid turn at the point of launch with edge angles and preasure, then that tangential direction will not be the direction the boots are pointing. Perhaps you released just prior to line up the skis to that tangential direction, or perhaps you flew through the air with the skis at least initially not pointing that direction. A well timed release can be like rolling a bowling ball smoothly. This would zero in to zero steering angle progressively right as the edges are released into launch. It's also the termination of turning. But if you are truly mid turn and truly on a pressured edge at the time of launch then it would be the latter. You would fly on a tangent that is not the direction your boots are pointing.

Why does this matter? If you are going to try to define skid angle as some kind of precise differentiating thing from steering angle then be precise. The direction the boots are pointing does not distinguish it. I think you will find the definition, if used at all, is related to the angle of the tails relative to direction of travel.
Quote:

Yikes again, BTS.  I fear this conversation is just complicating what is actually quite simple.

Everyone, have a look at the drawing above.  The black arcing arrows represent the actual direction of travel of the skier.  The skis represent the direction they point as the skier travels through the turn.  The more the ski is out of alignment with the direction of travel (black line), the larger the skid angle, the more friction is created, and the slower the skier will travel.  It's really no more complicated than that.  It's a 15 second explanation in an actual lesson, then you're off learning to do it.

Imagine the skis in the above drawing being in perfect alignment with the black line, not off set at all.  That's a carved turn.  It has no skid angle, zero.  But it has a steering angle, because the front of the ski points a different direction than the center of the ski, or as I put it, the boots.

Rich, I know you're trying to make sense out of this, so would you mind being my sounding board?  Does that make sense?

Quote:
Originally Posted by borntoski683

as others have said, an arced turn does not have zero steering angle. By the way at any given instant the CoM is not moving the direction the boots are pointing in an arced turn either. The skis have to deflect it that direction. Anyone who has ever lost an edge at the fall line can attest that you slide out to the side, not down the fall line. The tangential momentum is actually a fair degree outside of the direction the boots are pointing, including in arced turns. That's why we are able to feel pressure and bend the ski! The TAIL of the ski is closer to zero steering angle in an arced turn and even that is probably not totally zero, if you load up balance and pressure on the tail then it especially isn't.

zenny I agree with you, I almost never use these terms with students. It's fun to read lemaster and discuss this stuff theoretically but students need to learn movement skills. Most often I find these concepts are used to justify movement skills. The movement skills are what should be taught. The lemasterean physics are how we as instructors can determine if movement skills pass the smell test

In a pure carved turn, don't we simply steer the ski by tipping (AKA: edge angle) more or less, tightening or loosening the radius? And isn't steering otherwise simply blending rotary movement with skid production?

Quote:
Originally Posted by Rich666

In a pure carved turn, don't we simply steer the ski by tipping (AKA: edge angle) more or less, tightening or loosening the radius? And isn't steering otherwise simply blending rotary movement with skid production?

This is correct. When carving we steer the ski by tipping it. As you can see the word "steer" is a bit confusing. Thats why I use the word "skid" for so called "steered turns" insted. Steering angle was mentioned. I rather talk about skidding angle. As you can read from BTS's posting the steering angle is hard to define. Skidding angle is not. If you are carving and your ski is running along its edge its carving. If its brushing over the snow slightly sideways then its skidding. Anyone that can carve and skidd knows the difference.

Edit: didnt read Ricks post.... well explained, thanks!

Quote:
Originally Posted by Rick

Yikes again, BTS.  I fear this conversation is just complicating what is actually quite simple.

Everyone, have a look at the drawing above.  The black arcing arrows represent the actual direction of travel of the skier.  The skis represent the direction they point as the skier travels through the turn.  The more the ski is out of alignment with the direction of travel (black line), the larger the skid angle, the more friction is created, and the slower the skier will travel.  It's really no more complicated than that.  It's a 15 second explanation in an actual lesson, then you're off learning to do it.

Imagine the skis in the above drawing being in perfect alignment with the black line, not off set at all.  That's a carved turn.  It has no skid angle, zero.  But it has a steering angle, because the front of the ski points a different direction than the center of the ski, or as I put it, the boots.

Rich, I know you're trying to make sense out of this, so would you mind being my sounding board?  Does that make sense?

Yes, Rick, as soon as I saw this visual aid, that is exactly how I understood it. To be honest trying to understand the questioning of it is where I get lost. Bringing the concept from steering angle down to skid angle seems to effectively narrow the range of interpretation. I have found from the thread above that the concept of steering angle contains too many variations and technicalities to extend to a student audience.

And the effective steering angle of a purely arced ski is simply the depth of the "bend" dictating the radius of the ski's travel. Which simply translates to "edge angle". As I see things so far.

Quote:
Originally Posted by Rick

Yikes again, BTS.  I fear this conversation is just complicating what is actually quite simple.

Everyone, have a look at the drawing above.  The black arcing arrows represent the actual direction of travel of the skier.  The skis represent the direction they point as the skier travels through the turn.  The more the ski is out of alignment with the direction of travel (black line), the larger the skid angle, the more friction is created, and the slower the skier will travel.  It's really no more complicated than that.  It's a 15 second explanation in an actual lesson, then you're off learning to do it.

Imagine the skis in the above drawing being in perfect alignment with the black line, not off set at all.  That's a carved turn.  It has no skid angle, zero.  But it has a steering angle, because the front of the ski points a different direction than the center of the ski, or as I put it, the boots.

the black line is only followed because of continual deflection and redirection by the skis through steering angle, primarily under the foot!  zero steering angle under the foot would not deliver that result.

We can say that the front of the ski will always have more steering angle then the foot and tail.  As you move back towards the rear of the bent ski, the steering angle gets smaller and smaller.  Can it ever be negative?  I say no for parallel turns.  If the steering angle under the foot is zero, the tail would theoretically have to be negative.

When can a negative steering angle occur?  It can happen in wedged turns when a beginner is not flattening the inside ski enough.  Its literally edged on its outside edge with the sidecut backwards.  So the tail of that inside ski will literally gouge into the snow due to negative steering angle.

But this does not happen in parallel turns and thank goodness.

The tail of the ski might reach zero steering angle, or perhaps a small bit more, particularly if the skier is loading the tails.  However anything in front of the tail will have more steering angle then zero....even in arced turns!

The skier will only be sent on that curved path by this very mechanism.

Quote:
Originally Posted by Rich666

In a pure carved turn, don't we simply steer the ski by tipping (AKA: edge angle) more or less, tightening or loosening the radius? And isn't steering otherwise simply blending rotary movement with skid production?

some people think that by twisting their skis they can steer them.  However, this the rub, twisting your skis either flattens them or disengages the tail.  Disengagement either way which is loss of directional and speed control.  Covered this earlier in the thread.  At slow speeds on flat terrain it can work ok to flatten and get away with twisting.  Up the ante and that approach will not work.  Tipping finese and fore-aft balance can steer your skis, including non-arced turns also.  This method allows you to use higher more effective edge angles while steering tight turns.  Thus more directional and speed control.  Twisting them less.

Quote:
Originally Posted by Rich666

Yes, Rick, as soon as I saw this visual aid, that is exactly how I understood it. To be honest trying to understand the questioning of it is where I get lost. Bringing the concept from steering angle down to skid angle seems to effectively narrow the range of interpretation. I have found from the thread above that the concept of steering angle contains too many variations and technicalities to extend to a student audience.

And the effective steering angle of a purely arced ski is simply the depth of the "bend" dictating the radius of the ski's travel. Which simply translates to "edge angle". As I see things so far.

Steering angle applies to all turns, not just arced turns.

There is absolutely nothing complicated about the concept of steering angle except when skid angle idea is introduced and one tries to distinguish the difference.

Quote:
Originally Posted by borntoski683

some people think that by twisting their skis they can steer them.  However, this the rub, twisting your skis either flattens them or disengages the tail.  Disengagement either way which is loss of directional and speed control.  Covered this earlier in the thread.  At slow speeds on flat terrain it can work ok to flatten and get away with twisting.  Up the ante and that approach will not work.  Tipping finese and fore-aft balance can steer your skis, including non-arced turns also.  This method allows you to use higher more effective edge angles while steering tight turns.  Thus more directional and speed control.  Twisting them less.

Steering angle applies to all turns, not just arced turns.

There is absolutely nothing complicated about the concept of steering angle except when skid angle idea is introduced and one tries to distinguish the difference.

This does not make any sence. Steering angle is a confusing consept. Dont use it. Insted use skidding angle. Check out your tracks in the snow. Its easy to see where you skidd and where you carve. Where you carved clean tracks all parts of the ski carved. Skidding angle cero. In a skidded turn usually the tail skidds more than then tip. Also, why talk about negative steering angles? Thats almost like talking about skiing wth the ski flipped upside down... and just for the record, skidding your turns is just about as important as being able to carve them. In fact even more important.

read the whole thread TDK, then maybe my comments will make sense to you, regardless of whether you agree with me or not.

I don't ever teach with either outcome based concept, I teach movement skills.

Outcomes can be arcd, carved, skidding, etc, but I have no use whatsoever to teach skid angle as a concept, its an outcome anyway for one thing, and for another thing, I have listed off all the reasons why I don't think its an effective outcome to shoot for large "skid angles".  someone else in the thread asked about what the difference is between the more mainstream term of "steering angle", and Rick's "skid angle".  We have been elaborating on that point for a while.  Try to keep up.  ;-)

Sorry BTS. Did not read past Ricks post. Just out of curiosity, what about very short turns with lets say GS skis where the pivot point lies under the foot or slightly ahead? Im getting a head ache by just thinking about it....

what about it?  Will have to be flat and pivoty yes, probably with hard edge sets at the end of each turn, which is not the same as "wide tracked steering"

OMG, the confusion is self imposed my friends. Stop trying to layer superfluous ideas onto the simple idea. Both ideas redirect the CoM into the turn, one features more reaction force because more force has been applied to the snow. Allowing some skid, or even more skid is not outside what a beginner can fathom though. If anything the opposite is more the case.

agreed, skidding seems to come naturally to most learning skiers.  Unfortunately, left unchecked that will not lead to the most effective directional and speed control.

As a learning intermediate who's trying to keep up with this thread, it seems to me that a diagram addition to this one :

to show the amount of tipping, and curve/flex of the ski in each of the two scenarios above would be helpful. (Much like the popular Bob Barnes turn diagram that has the amount of tipping at different points in the turn.) Maybe carved turns could be added too? In this case, wouldn't tipping, ski flex (creating steering angle), and skid angle all go hand in hand? I.e. :

-- Large skid angle = moderate tipping = little flex of the ski

-- Small skid angle = larger amount of tipping = larger flex of the ski

-- No skid angle (carved/arced) = largest amount of tipping = largest flex of the ski

Does that sound right?

Quote:
Originally Posted by Rick

Sorry there, A man!  It's a good one, couldn't help myself.  I'll make it up to you; go ahead and use mine if you want.

DEAL!   The unfortunate part is it's truer every day!

Quote:
Originally Posted by Rich666

Yes, Rick, as soon as I saw this visual aid, that is exactly how I understood it. To be honest trying to understand the questioning of it is where I get lost. Bringing the concept from steering angle down to skid angle seems to effectively narrow the range of interpretation. I have found from the thread above that the concept of steering angle contains too many variations and technicalities to extend to a student audience.

And the effective steering angle of a purely arced ski is simply the depth of the "bend" dictating the radius of the ski's travel. Which simply translates to "edge angle". As I see things so far.

Thanks for the feedback, Rich.  Yes, you're right, it's really a simple concept that only gets confusing when the arguments erupt.  When long dissertations set out to prove black is actually white, long is actually short, high is actually low.  Pity the poor souls who try to make sense of it.

Quote:
Originally Posted by Atomicman

DEAL!   The unfortunate part is it's truer every day!

Tell the truth, though, A man.  In the spirit of the one time Epic personality, SCSA, you're still faster than 97 percent of the skiing population.

Quote:
Originally Posted by dbostedo

As a learning intermediate who's trying to keep up with this thread, it seems to me that a diagram addition to this one :

to show the amount of tipping, and curve/flex of the ski in each of the two scenarios above would be helpful. (Much like the popular Bob Barnes turn diagram that has the amount of tipping at different points in the turn.) Maybe carved turns could be added too? In this case, wouldn't tipping, ski flex (creating steering angle), and skid angle all go hand in hand? I.e. :

-- Large skid angle = moderate tipping = little flex of the ski

-- Small skid angle = larger amount of tipping = larger flex of the ski

-- No skid angle (carved/arced) = largest amount of tipping = largest flex of the ski

Does that sound right?

It does sound right, dbostedo.  While there are a range of edge angles that can be used with each size skid angle, what you say here pretty well categorizes which end of the edge angle spectrum those ranges dwell on.

Haven't seen A-man @ Bachelor this spring.
Quote:
Originally Posted by borntoski683

some people think that by twisting their skis they can steer them.  However, this the rub, twisting your skis either flattens them or disengages the tail.  Disengagement either way which is loss of directional and speed control.  Covered this earlier in the thread.  At slow speeds on flat terrain it can work ok to flatten and get away with twisting.  Up the ante and that approach will not work.  Tipping finese and fore-aft balance can steer your skis, including non-arced turns also.  This method allows you to use higher more effective edge angles while steering tight turns.  Thus more directional and speed control.  Twisting them less.

Steering angle applies to all turns, not just arced turns.

There is absolutely nothing complicated about the concept of steering angle except when skid angle idea is introduced and one tries to distinguish the difference.

I think I do understand your efforts in explaining the steering angle and agree with you in regards to just about everything you state including that the steering angle concept is the preeminent/predominant of the two concepts. I also think it is pretty clear that you have a sound understanding of the finer bio-mechanic complexities. A couple things, though ...

While the edge angle concept may be the newly introduced concept in ski instruction, it is the steering angle concept that is the newly introduced concept within this thread. Just sayin ...

Secondly, the steering angle concept brings with it torsional twisting variables along with a breakdown of fore, mid and aft dimensions of the ski - as you describe, that is null and void within the edge angle concept. I think the differences between the two concepts are very much in line with a lot of what Rick has accomplished within the realm of the still emerging DVD/online ski instruction space. Compared to everything else I have found online, Rick, in my mind, probably excels the most in reinterpreting to what many learning skiers may find are overly technical and intimidating aspects of skiing. His foundation and fundamental based "building block" approach to learning is genius in its cognitive simplicity while meeting the complex athletic learning requirements of a very technically sophisticated sport. As far as I can see, the majority of difference with anything more recent is cosmetic. Even the PSIA has resorted to teaching switch in stretching their reach for something new. Just about everyone within this space can ski very well. Teaching it well, however, proves to be far more difficult.

hey the only reason we're talking about steering angle is because Rick brought up skid angle and some us interchanged steering angle and skid angle in our verbology and somebody asked about what is the difference.

Quote:
Originally Posted by Rick

While there are a range of edge angles that can be used with each size skid angle...

Based on what? Snow conditions? Speed? Weight distribution between legs? Amount of angulation? All of the above?

Quote:
Originally Posted by dbostedo

Based on what? Snow conditions? Speed? Weight distribution between legs? Amount of angulation? All of the above?

The turn shape you desire.  At a particular skid angle, a slight increase in edge angle will reduce the turn radius.  Conversely, a slight decrease in edge angle will increase turn radius.  To maintain the desired skid angle, you will also have to manage the amount of leg steering power you use.  That, too, involves only small changes.

The best way to learn to do this is to pick a turn shape and skid angle combination, and strive to maintain them through an entire turn.  Body/mind magic generally figures it out pretty quickly.

My wife is a disabled skier with severely limited proprioception, who didn't start skiing until her late 30's, and she figured out how to do this in short order.  You can see her demonstrate some of it in our edging progression video that has been posted here on Epic a couple times recently.  She raves about how it has improved her skiing, and allowed her confidence while on any type of terrain to soar.

Quote:
Originally Posted by Rick

Tell the truth, though, A man.  In the spirit of the one time Epic personality, SCSA, you're still faster than 97 percent of the skiing population.

I can still turn 'em!

Quote:
Originally Posted by Rick

Quote:
Originally Posted by dbostedo

Based on what? Snow conditions? Speed? Weight distribution between legs? Amount of angulation? All of the above?

The turn shape you desire.  At a particular skid angle, a slight increase in edge angle will reduce the turn radius.  Conversely, a slight decrease in edge angle will increase turn radius.  To maintain the desired skid angle, you will also have to manage the amount of leg steering power you use.  That, too, involves only small changes.

The best way to learn to do this is to pick a turn shape and skid angle combination, and strive to maintain them through an entire turn.  Body/mind magic generally figures it out pretty quickly.

My wife is a disabled skier with severely limited proprioception, who didn't start skiing until her late 30's, and she figured out how to do this in short order.  You can see her demonstrate some of it in our edging progression video that has been posted here on Epic a couple times recently.  She raves about how it has improved her skiing, and allowed her confidence while on any type of terrain to soar.

Ahhh, but because steering angle varies from a maximum at the tip to a minimum at the tail you CAN also manage skid angle and turn radius by adjusting fore-aft weighting of the skis without adding "leg steering" as a an applied torque about an axis perpendicular to the plane of the ski (IIRC, this technique is what BTS advocates).

Quote:
Originally Posted by Ghost

Ahhh, but because steering angle varies from a maximum at the tip to a minimum at the tail you CAN also manage skid angle and turn radius by adjusting fore-aft weighting of the skis without adding "leg steering" as a an applied torque about an axis perpendicular to the plane of the ski (IIRC, this technique is what BTS advocates).

Sounds like a very keen regression to the days of old. I remember very well skiing on straight skis and managing ski pressure movement from the shovel to the tail within each and every turn. As Ghost insightfully reminds me was that this movement was also integrated with the other steering forces applied to the ski (edge and skid angles). The quickening, delaying, abbreviating or lengthening of these movements all work in concert to determine and adjust turn size and shape. At least speaking for myself, that fore/aft movement, for the most part, ceased with the arrival of shaped skis and appreciate that it represents one less thing to worry about.

Actually, although it is not required to arc turns on shaped skis, it (fore-aft balance and weighting control) is still useful in fine tuning CoM position relative to current impulse (force x time) and future intended direction changes, and very usefull when making turns that are not arced.  You're probably not worried about it because you do it automatically, as required (e.g. no need to prebend the tip before tipping, but useful for other purposes).

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