 Poster: A snowHead
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I've spoken before here about the importance of possessing good steering skills. We've just put a new entry on our glossary that explains the turn shape limitations associated with carving. I plan to do an article on this, but in the meantime I thought I'd throw this up here for you folks to have a look at. It shows pretty clearly what I'm referring to. If you have any questions about it, feel free to hit me with them.
A big thumbs up to Janis (Little Tiger) for the great drawing.
To have a look at the entry, go to this link and see "Carve Zone". http://www.yourskicoach.com/YourSkiCoach/C.html
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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I have always wondered.....
A ski will usually have its turn radius (Minimum carve radius) printed..... lets say 15m
Apart from just looking at the ski side cut and guessing what the Max radius is is there a way to quickly give a more acurate result apart from looking at all the tip,tail, waist and flex then doing some calculations?
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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daehwons, The radius printed on the side is the MAXIMUM turn radius.
The minimum radius is a trickier thing to know as it involves tipping the ski on edge to reduce from the maximum. The higher you tip the more you reduce. Much in the formula has to do with the ability of the skier to tip the ski up to a high edge angle.
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You need to Login to know who's really who.
You need to Login to know who's really who.
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little tiger, and to apply pressure to it at the same time.
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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FastMan, uh?
Sorry, don't get this at all. The maximum turn radius is (effectively) infinite, otherwise you couldn't ski in a straight line (infinite curvature).
Your "max turn radius" assumes perfect carving I think )and infinite torsional rigidity). Which skis don't do (have) in practice (no matter how good the skier is).
Consider a soft, very, very, shaped ski, with marginal weight on it and marginal edge. The tips and tails will catch, forming a carve, but its radius will not be the same as the ski radius.
No???
I love your Glossary section on "M" though. Where's "Moguls"?
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You'll need to Register first of course.
You'll need to Register first of course.
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this is going to get messy.....
im going to revert back to my "wine selection" method..... look at the bottle and if it looks nie and is a good price then it should be ok.
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under a new name, the maximum turn radius with the edge fully engaged and not slipping is as per the circle described by the hourglass of the ski's shape. Any turn radius larger than this will involve a certain amount of slipping of at least part of the ski edge. When skiing in a straight line for example, the ski edges at the tip and tail are slipping - they are slightly across the direction of travel.
But I think you're right - a ski's stiffness does come into play when things get more complex such as with a twin radius ski.
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Thanks for the feedback everyone, here are some responses.
daehwons, little tiger is right. The radius designation on the ski is the radius of the circle that would be produced if the ski's sidecut was projected into a complete circle. It's the largest turn radius that ski can carve. In reality that maximum radius will be slightly smaller because some further tipping and bending has to happen for the ski's edge to engage the snow, but it's close enough for just trying to explain the basic concept. As you tip the ski higher on edge the center of the ski would lift further off the snow, but pressure applied by the skier bends the ski to keep its center engaged in the snow. The extra bend reduces the radius of the carved turn. The more the ski is tipped on edge, the more it has to be bent to stay in contact with the snow, so the sharper it carves.
easiski hits on an important point; this whole concept of carving various radius turns depends on a skier's ability to remain balanced on the ski while it's being tipped on edge. Enter angulation.
under a new name, mfj197 nailed it. To carve a turn larger than the ski's built in curvature (sidecut) some skid has to happen. It's why racers use skis with less sidecut for downhill events than they do for slalom, because they'll carve a longer radius turn. In racing, carving is key to being fast. Oh yeah, and it's also safer. Imagine the ugly scene if a curvy little slalom ski were to hook up into a carve when traveling 80 mph through a mega radius turn. It would be Bill Johnson times 4.
under a new name, thanks for the thumbs up on our glossary. We're a work in progress. Many more entries are on the way shortly.
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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| little tiger wrote: |
| The minimum radius is a trickier thing to know as it involves tipping the ski on edge to reduce from the maximum. The higher you tip the more you reduce. Much in the formula has to do with the ability of the skier to tip the ski up to a high edge angle. |
For the geeks in the house Ron LeMaster's new book (Ultimate Skiing) has some useful stuff on how edging affects turn radius.
| Ron LeMaster wrote: |
A good approximation for the carving radius of a torsionally stiff ski held at an edge angle of 45 degrees on hard snow is 70 percent of the ski's sidecut radius. At 60 degrees, the carving radius is 50 percent.
More precisely, a ski with a sidecut radius of R(sc) held at an edge angle A and bent into reverse camber that brings the entire edge into contact with the snow will cut an arc with radius R = R(sc) cos A. This assumes the ski's sidecut is a section of a circle (which most are) and the ski doesn't flex dynamically in torsion. |
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FlyingStantoni, is that SH's first cosine?
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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| pam w wrote: |
| FlyingStantoni, is that SH's first cosine? |
I'd be really surprised if it was.
I mean...there are people who are a lot sadder than I on this forum 
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| comprex wrote: |
| FlyingStantoni, do you have a copy of Lind and Sanders? |
I don't.
And HOW MUCH?????!!!! 
(Unless the book comes with a free instructor...)
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You know it makes sense.
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FlyingStantoni, oh come on, don't be such a tightwad. You can get a second hand one for a mere $62.
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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Poster: A snowHead
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laundryman, 
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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If my idiot maths teacher had only explained all those years ago that geometry would be an essential part of being a ski instructor I might well have paid a bit more attention.
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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this thread is heading off at a Tangent
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You need to Login to know who's really who.
You need to Login to know who's really who.
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FastMan, duh, I think I get the race thing, thanks.
But isn't this all a little theoretical? Assuming a fully engaged edge, no torsion, (would have to be on ice as you couldn't have the ski sinking into the snow) and we're straight into the realm of the theoretical and straight out of the real world.
Which suggests to me that it's a little less than a practically useful concept ( the carve zone).
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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FastMan, so you were listening to me in L2A  but your example is the condition that I was in by having to be centred over the ski with no fore or rear bias that effectively shortens both the effective edge length and the radius of the carve.
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You'll need to Register first of course.
You'll need to Register first of course.
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| under a new name wrote: |
FastMan
But isn't this all a little theoretical? |
I'm not sure how the defining of maximum and minimum carve radii can be anything other than "theoretical" in that they have to be determined by criteria which are measurable, definable and not subjectively related to the skiing ability of any individual.
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| Masque wrote: |
| FastMan, so you were listening to me in L2A but your example is the condition that I was in by having to be centred over the ski with no fore or rear bias that effectively shortens both the effective edge length and the radius of the carve. |
Hi Masque, hadn't seen you posting here for a bit, glad to see your still alive and kickin. Those were fun tech discussions we had last summer in L2A. Your comments above are spot on. A turn's radius can be somewhat reduced by concentrating pressure to one section of the ski. When hyper loading the front of the ski, part of that radius reduction can also come in the form of carve corrupting tail displacement (smear/skid). That's not a factor with tail loading, but with the shorter skis of the day it's a tactic that needed to be employed with more caution than in yesteryear.
Hope the Masque Mobile venture is moving along on track.
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| under a new name wrote: |
FastMan, duh, I think I get the race thing, thanks.
But isn't this all a little theoretical? Assuming a fully engaged edge, no torsion, (would have to be on ice as you couldn't have the ski sinking into the snow) and we're straight into the realm of the theoretical and straight out of the real world.
Which suggests to me that it's a little less than a practically useful concept ( the carve zone). |
under a new name, the value of the concept is twofold. First, it's very helpful in choosing a ski to purchase. Different sidecuts will provide very distinct carving experiences. Skiers should understand that, and choose accordingly with their individual tastes. it also explains why some skiers have a quiver of different sidecut skis. Different skis to provide a wide range of different types of skiing fun.
The concept also makes clear the importance of learning good steering skills. Expert skiing is not all about carving. It can't be. The turn shape limitations of carving, as depicted in the carve zone drawing, will leave a skier of poor steering skills struggling on difficult terrain. In the rush to teaching carving to learning skiers, foundation steering/edging skills often get brushed over much too quickly. The result is usually of a skier hitting an improvement wall, stuck with low quality steering AND carving skills. In those cases, the carve zone is even more limited, as the skier does not possess the foundation skills to employ a full range of edge angles. ccl hits on that in his post. It's a vicious dead end cycle.
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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FastMan, sorry, I'm still disagreeing. I think it's overcomplicating the game. Already complicated enough. It's surely enough to say that
| Quote: |
| Expert skiing is not all about carving. It can't be. |
I just kind of think that the diagram requires so much prior explanation that its going to get in the way. Most recreational skiers I know have no idea (no matter how much they might discuss it (just like "stiffness")) of what is really going on.
Notwithstanding the fact, of course, that they should be aware. Ho hum.
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But, under a new name, are the glossary in general and the item about carving aimed only at the recreational skier? I found that particular article and the diagram more than just interesting: they filled in a few gaps in my knowledge and understanding.
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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ccl, Good! How did it help? (really, serious question, genuinely curious).
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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FastMan, at the moment I'm driving 12,000+ miles a months getting the needed road time to meet insurance demands for the project. On the above theme, should I try to explain why sidecut allows a ski to bend more under less pressure so that the inner ski will track inside the outer while being lighter pressured?
That's gonna fry some minds 
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Masque, sounds fascinating!
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You know it makes sense.
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| under a new name wrote: |
FastMan, sorry, I'm still disagreeing. I think it's overcomplicating the game. Already complicated enough. It's surely enough to say that
| Quote: |
| Expert skiing is not all about carving. It can't be. |
I just kind of think that the diagram requires so much prior explanation that its going to get in the way. Most recreational skiers I know have no idea (no matter how much they might discuss it (just like "stiffness")) of what is really going on.
Notwithstanding the fact, of course, that they should be aware. Ho hum. |
I agree with you, there is a progression of learning involved with coming to understand the drawing. A skier first has to learn how carving even works, such as the role of sidecut, and how and why edge angle controls turn shape. Without that base of understanding, the drawing won't make sense. This entry in the glossary is simple a piece of the puzzle, an important piece for people to come to understand the totality of ski technique, and why learning good steering skills is so crucial.
For some, the statement "Expert skiing is not all about carving. It can't be" is enough to suffice. They will accept it at face value, without really knowing why the statement is true. For others, they won't just blindly accept the statement as gospel, they have to understand why. The carve zone drawing is part of the explanation.
If anyone looked at the drawing and got dizzy, I'll be happy to explain it further.
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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FastMan, OK I'm glad we're not disagreeing!
Actually, it amazes me that so few skiers understand what the ski is trying to do. And how you can work with it or against it.
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FAQ
