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A great picture of a PMTS lesson! - Page 4

post #91 of 117
Suppose this is true: The ski bends as infinitesimally small but tight radius arcs at the front, and infinitesimmal small but longer radis arcs at the back.

Why must the ski wash? If the ski at it's tail cannot make as small an arc as the tip, the ski will just compress the track. Washing is sideways, and to me, implies pivotting.
post #92 of 117
Arced side slip?
post #93 of 117
Quote:
Originally posted by daslider:
BigE

I also use 'wash' as a sideways movement as opposed to one straight along the 'track'. Isn't compressing the track sideways also widening the track to accomodate the changing shape of the ski? That's why I called it microwash as it is a sideways movement.
In the case of a uniform sideways displacement, I'd prefer to use "skid" or "microskid". The edge angle is sufficient to engage, but the quality of the snow pack will not hold the track -- it shifts and gets pushed somewhat down the hill. Just like I imaging ydnar's arced side slip.

Quote:
Originally posted by daslider:

To be frank, I'm not sure quite how this change of ski shape is accomodated. There seem to be 2 posibilities:

1/ The tip deflects and carves a sharper radius which the rest of the ski follows as it is drawn into the tightening turn, more like the waggons following the engine around a bend.

2/ The increased loading of the ski via the foot pushes out the midsection increasing the reverse camber which will cause a widening of the track (or microwash).

Now as the only input into this 'system' comes from the foot, I favour No 2 as I can't see that the tip can deflect on its own.
Or, it's a combination:

The tip deflects and carves a sharper radius which the rest of the ski cannot follow. The increased loading of the ski via the foot pushing out the midsection increasing the reverse camber will then cause a displacement, ie. compression/deepening of the track. A microskid if you will... :

In short, the shape of the ski can be considered a spiral segment, where the tip behaves like a plow. Much like a toboggan...

So every point on the ski does not necessarily need to cross that trail begun by the tip for us to feel that the ski is carving.

Each point of the edge will cross the tip's trail only when the bend radius of the tip is no larger than the bend radius of the center of the ski, for the given pressure (it's reverse camber), AND the snow pack is so dense that no displacement (microskidding) occurs. This feels like the ski is locked into the hill or has completely "hooked up".

IMO, you'd have to be skiing very gently/passively and have the proper flex pattern underfoot for your weight and speed to make this actually happen.

That's my complete model of what is happening. If it is correct, then it follows that skis that are too soft will never hook up at normal speed.
post #94 of 117
over on Realskiers SCSA made some sort of comments that Pierre got hurt. Not sure if he is referring to the same Pierre or not. Here is a link:

http://www.realskiers.com/pmtsforum/viewtopic.php?t=206
post #95 of 117
BigE

I also use 'wash' as a sideways movement as opposed to one straight along the 'track'. Isn't compressing the track sideways also widening the track to accomodate the changing shape of the ski? That's why I called it microwash as it is a sideways movement.

To be frank, I'm not sure quite how this change of ski shape is accomodated. There seem to be 2 posibilities:

1/ The tip deflects and carves a sharper radius which the rest of the ski follows as it is drawn into the tightening turn, more like the waggons following the engine around a bend.

2/ The increased loading of the ski via the foot pushes out the midsection increasing the reverse camber which will cause a widening of the track (or microwash).

Now as the only input into this 'system' comes from the foot, I favour No 2 as I can't see that the tip can deflect on its own.
post #96 of 117
First...... Turns are not necessarily circles or spirals. They can be circles, spirals, reverse spirals, combination spirals, or erratic.

Get what I'm saying here? We can make any turn shape we choose. We have complete control over the degree of edge we employ at every point of the turn, we are not locked into any one particular turn shape. Park and ride? If by that you mean locked into one edge angle, well, it's not bad necessarily, it's just another turn shape option.

As far as the center displacement that occurs as we adjust edge angle, thus ski bend, thus turn shape? Sure it happens, so what. It's so minuscule you won't see it when you watch someone execute a refined carved turn. You won't see it in the track unless the snow is very soft (as described by ydnar, but I question if we truly carve turns in soft snow anyway. You carve a turkey, you don't carve whipped cream). You won't feel it on packed snow.

Anyone, if the issue of center displacement is so minuscule and indistinguishable how do we apply the knowledge of it's existence to interaction with students? Does it affect the manner in which a balanced platform is created? Does it affect the manner in which turn shape is altered? Does it influence turn completion or turn initiation? Does it play a role in rotational issues. How do we use this little tidbit of knowledge to impact student development?
post #97 of 117
Fastman

The important thing about spirals is they are changing, whereas a circle is fixed. You will find this subthread stems from assertions that purely carved turns cannot change radius by extension of the foot - something which I think we now agree is ridiculous. I do think there is a lesson in this in that no significant part of a turn is entirely passive, there is always something going on (what some call offensive skiing). Taking a ride on a carving ski in benign conditions is actually quite fun, but it can all too easily be thought of as the end of the story which is what 'park and ride' means to me?

Is your whipped cream analogy mistaking the role of the edge in carving? Carving is done with the skibase which is why powder can be skied. The edge merely allows the base sufficent purchase on the snow.

A ski which was just a side edge, with little base edge and an open lattice where the plastic base is normally, would not ski (it would be like sharpening an ice skate to razor thinness - it wouldnt work either, it is the base that does the business)
post #98 of 117
Quote:
Originally posted by FastMan:
...You carve a turkey, you don't carve whipped cream...
This is such a great turn-of-phrase, and something I've been thinking about for a while, so I couldn't resist responding. I didn't want to derail this thread, so I put it in a new thread .

Tom / PM

[ May 08, 2004, 01:22 AM: Message edited by: PhysicsMan ]
post #99 of 117
No daslider, no mistake in my analogy. My statement referred more to the medium.

Carving is done with the edge and the base. Something has to cut the shape of the platform on which the base travels, that would be the edge.

I'll reply more to this topic in PM's new thread. In the meantime, how about an answer to me previous question........

"if the issue of center displacement is so minuscule and indistinguishable how do we apply the knowledge of it's existence to interaction with students? Does it affect the manner in which a balanced platform is created? Does it affect the manner in which turn shape is altered? Does it influence turn completion or turn initiation? Does it play a role in rotational issues. How do we use this little tidbit of knowledge to impact student development?"
post #100 of 117
Quote:
Originally Posted by Rick

"if the issue of center displacement is so minuscule and indistinguishable how do we apply the knowledge of it's existence to interaction with students? Does it affect the manner in which a balanced platform is created? Does it affect the manner in which turn shape is altered? Does it influence turn completion or turn initiation? Does it play a role in rotational issues. How do we use this little tidbit of knowledge to impact student development?"
Here's a couple of thoughts --

Center displacement implies micro-skidding. Micro-skidding makes a sound on hardpack.

I suggest that the ideal carve would be silent. This means that the skier should try to keep the skis as quiet as the situation permits. One should note that the skis of a skier that does not flex and is not supple (eg. locked legs) will be far noisier than the skis of a skier that does flex and is relaxed. The center displacement will be larger under a locked leg, and so will the resluting sound of skidding.

Also, the greater the center displacement, the less hooked up the skier will feel. The relaxed and flexing skier will have minimal center displacement, and so will feel far more hooked up. They will need to be more mindful of the position(s) in which they maintain balance to ensure that the center displacement is minimized. Obviously, park and ride is not optimal.

Just my 2 cents!

Cheers!
post #101 of 117
Big E, the displacement being referred to here is simply the theoretically unavoidable lateral movement of the skis center when edge angle is changed.

It goes something like this. When edge angle is increased the space between the snow and the portion of the skis edge under the foot increases. To regain contact with the snow the ski bends more, which drives the center of the ski further outside and reduces the radius of the turn. That smaller radius turn creates an increase in the centrifugal forces impacting the ski which in turn further adds to the bending of the ski, and thus the displacement. This is the center displacement being referred to. It also works in reverse when edge angle is decreased, in which case center displacement is back toward the inside as the ski straightens.

That is the theory. Does it happen just that way on snow? I can't attest to it. I've never felt it when carving clean turns on hard pack snow and my track does not reflect this taking place. My suspicion is that because the ski is so strongly engaged and locked into an arc that when edge angle is increased the greater ski bend is at least partially achieved by the tip being forced into carving a tighter arc and the rest of the ski following along the new sharper curved track. That scenario, while only speculation, would better correspond to what I feel and observe.
post #102 of 117
Sorry, I thought you were referring to the center displacement such that the midsection of the ski cannot follow the radius of the turn that the tip of the ski is scribing, since the tip is more flexible.
post #103 of 117
That's what I thought also when I first tapped into this thread and heard talk of center displacement in association with carving. What I first thought they were saying (continuous center displacement/sliding) has no place in carving, in fact it's even hard to accomplish if one desired to do it, so I was very much opposed to the idea.

I'm willing to accept the idea as later clarified as a theoretical possibility, but I'm not yet willing to endorse it. I don't feel it when I ski, I don't see it in tracks, and my intuition tells me the displacement manifests more in the tip being forced into a new tighter arc.
post #104 of 117
Fastman Rick

I've been away for a bit, apparently since December 1969. I suppose this question concerns the mechanism by which radius change occurs. What was being argued here was that the skier's boot is the only input in this equation and that this is how and importantly WHERE the ski shape and consequently its radius changes. This distorting of ski shape has to widen the track producing the microwash or whatever expression you would prefer.

Looking at it the other way around, what possible mechanism can deflect the ski tips into a tighter arc (assuming even snow and thus excluding such obstacles as bumps) when the only outside force is applied at the ski's midpoint?

I'm not surprised you haven't seen this in ski tracks, the developing radius of such a spiral is subtle and the snow an inconsistent medium not really susceptible to precise measurement anyway. If the spiral progresses smoothly, its rate of radius change isn't abrupt and the sensation is probably of the foot always either tightening or lengthening the arc by the progressive 'washing' we have discussed.

I think this whole picture is clarified by forgetting the idea of fixed radius circular motiion when the likelyhood is of skiturns being progressively changing spirals as found in so many natural motions (golden sections etc).

You asked me earlier about the relevance to teaching of this microwash; well I think it is useful conceptually as it departs from the notion of skis having fixed geometry which we just get on and ride, there is always a continuing and changing input to be made.
post #105 of 117
Quote:
Originally Posted by daslider

Looking at it the other way around, what possible mechanism can deflect the ski tips into a tighter arc (assuming even snow and thus excluding such obstacles as bumps) when the only outside force is applied at the ski's midpoint?

What your proposing seems a very logical hypothesis of how a carve radius reduces. My hesitation in accepting it without question is because my intuition, which is based on many years of making, feeling and observing carved turns, leads me to consider another possibility.

I'll try the best I can to explain the alternate mechanism I envision. Imagine carving a turn on a very hard surface, with edges that are razor sharp. You are carving a moderate edge angle turn and because your ski is razor sharp it has cut a significant platform into the hard snow surface.

Now gradually increase the edge angle. Because the snow is so hard the platform the ski has cut is of such high integrity it can't be sheered or compacted enough to bend the ski into the shape the sidecut demands at this new edge angle. And because predominant pressure on the ski is directed at the underfoot portion of the ski it is forced to remain in the platform it has cut into the snow, it can't skip up and out.

So what is the ski to do? It desires to bend into a new shape, but the hard platform it has cut for itself will not allow it to displace outwardly at the skis center or inwardly at the skis tip. Something has to give. My hypothesis is that it gives at the tip. The ski being forced into a shape it doesn't desire to be in causes it to carry a stored energy which is released the only way possible, by the tip cutting a sharper arc as it travels forward and out of it's previously cut track, at which point it's free to deflect inward and cut a sharper arc.

As I said, I have no proof this is how radius reduction on a hard snow surface actually occurs, but it better coincides with my sensory perception. I'd be interested to hear PM's thoughts on the feasibility of this hypothesis.
post #106 of 117
Quote:
Originally Posted by Rick
My hypothesis is that it gives at the tip. The ski being forced into a shape it doesn't desire to be in causes it to carry a stored energy which is released the only way possible, by the tip cutting a sharper arc as it travels forward and out of it's previously cut track, at which point it's free to deflect inward and cut a sharper arc.

As I said, I have no proof this is how radius reduction on a hard snow surface actually occurs, but it better coincides with my sensory perception. I'd be interested to hear PM's thoughts on the feasibility of this hypothesis.
Yes that's how it "feels" to my proprioceptors too! When you increase the edge angle on boilerplate, you don't feel the middle of the ski sinking or drifting away, you feel the tip bite more. Or does that just come from a miniscule instinctive foot rotation in the direction of the turn, which, given an edged ski, would also have the effect of making the tip bite?
post #107 of 117
Quote:
Now gradually increase the edge angle. Because the snow is so hard the platform the ski has cut is of such high integrity it can't be sheered or compacted enough to bend the ski into the shape the sidecut demands at this new edge angle.
IMO, this can't happen. The force that made the platform is smaller than the new force that is applied. The "platform" thus created cannot be so strong that the new force has no effect -- it can only be strong enough to hold against the smaller force that created it in the first place.

Put another way: A shear force created a certain track. Now, with the ski edged even further, the shear force increases. Since a smaller shear force was responsible for a certain amount of deflection in the snow pack, a larger shear will create a large deflection. Otherwise, there is a tremendous non-linearity in the deflection vs. shear for that particular snow pack -- you are suggesting that once you get to a certain shear force, which had an effect on the snow, more force will have no more effect on the snow. That's some special kind of snow!!
post #108 of 117
You guys are thinking way too much about this. You really should take up a summer sport like golf or sailing.

Regards, John
post #109 of 117
Quote:
Originally Posted by jdowling
You guys are thinking way too much about this. You really should take up a summer sport like golf or sailing.

Regards, John
Or cyber skiing.....
post #110 of 117
Quote:
Originally Posted by BigE

The force that made the platform is smaller than the new force that is applied. The "platform" thus created cannot be so strong that the new force has no effect

RICK REPLY:

Not what I said. It does have an effect. As the ski is tipped to a higher edge angle the turn shape sharpens, and the centrifugal forces increase. Those higher forces do cause the skis edge to cut a new platform deeper into the snow and at a spatial orientation corespondent to the new edge angle.

The important points, however, are:

1) In very hard snow the platform will only increase in depth a minuscule amount, certainly not enough to accommodate the new shape the ski desires to assume. And:

2) The snow is of high enough integrity that it will not sheer.


Quote:
Originally Posted by BigE


it can only be strong enough to hold against the smaller force that created it in the first place.

RICK REPLY:

Not true. The sheer resistance of a surface does not have a direct relation to the amount of force used to cut a platform in that surface. The nature of the surface and the devise used to cut the platform into that surface have the most relevance.

The force needed to cut can indeed be smaller than the force the resultant platform will support. Just as the force an ice climber uses to get a bite in the ice with his crampon can be smaller than the force that bite will subsequently support.
post #111 of 117
Rick's crampon analogy is dodgy; the force to fix a crampon or drive in a nail is by design very efficient, it is designed to meet the minimum resistance in placing it but in its use exerting the maximum resistance, importantly accross a different axis (flat nails still pull out easily although they are strong to lateral forces, and crampons pull up and out by design while not sheering when in place).

The strength of the platform also has to be thought of dynamically as it is being continuously recut by the skitips. But as Big E says it is only as deep and as strong as it needs to be to create sufficient platform, if the forces change so will the platform but again by the dynamic adjustment of the cutting of that platform. It is pernmanently readjusting. This suggests the effective changes occur at the tips as Rick's instinct tells him.

Short of attaching some sort of leverage to the tips (by rods or wires) I can't see that the skier really has much direct control over his tips other than what can be applied through the feet. If we ignore for now the rotational forces possible and concentrate on the tipping of the ski, we know that increasing edge angle of the ski will tighten the arc which must change the relationship between the boot and the tip. So what gives?

I still think it is mostly foot pushing the ski into a new shape but in a subtle progression that is difficult to feel and almost impossible to see in loose snow, and impossible to measure. Even a speed skater on a bend creates some looseness; there is no perfect model. It is a process of micro-adjustment of both skier and ski, proprioceptive and mechanical.

Martin Bell's proprioceptors may feel the bite of the readjusting skitip, but due to the leverage of the boot moving laterally. In the same way that you feel the claw hammer extracting the nail although it is your hand on the hammer shaft in the opposite direction that is the sum of your actual input and the limit of what you should actually feel.

While the sidecut can be shown on a hard floor to facilitate the reverse camber of the ski, we also know that straight skis can be carved so by what mechanism are they increasingly bent as a turn tightens?

A penny rolled across a desk will turn to whichever side it leans. Does the skier's leaning provide the initiation that the bending ski then reinforces through its arced shape, so that it is the skier's imbalance that is the real motive force at work? More imbalance, more bend, more turn. Does this suggest the skier's imbalance actually pulls the tips into the turn, as it might pull a cyclist's front wheel around a bend?
post #112 of 117
Hope no one minds me coming late to the party.

I've been reading this thread lately with interest. There is some really good thoughts here but it seems that one thing has been left out, and that is simply the sidecut, and the resulting leverage and pressure that tipping puts on the tip and to a lesser degree the tail. What we have is an arc or radius we are riding on, but the axis of rotation of the tipping of the ski edge or arc is at the center under the foot, so when I tip the ski over further on edge this will place more pressure on the tip and tail because they are going to be displaced further into or against the surface. When this happens several things are possible, first is that the ski edge under the foot can have the pressure reduced forcing the ski to decamber further (pressure applied by extending the leg) to renew or maintain the platform under the foot, or if the rate of tipping is balanced with the speed or forward movement, the tip will respond to the pressure by bending more and tightening the arc but still keeping the entire edge engaged, which is the feeling I get when I sense my ski tip pulling me into the turn.

I don't know if there is anything wrong with either scenario, because much of what's happenning will depend on the intent, the hardness of snow surface, and the terrain.

I guess the third scenario is someone who just tips their ski over on edge and waits for the tip to grab and decamber the ski finaly engaging the edge.

Newton says for every action there is an equal and opposite reaction, so if the tip is pushing harder on the snow then the snow will push back harder on the tip, decambering the ski more and tightening the arc. To me it's all about the axis of rotation, and how far the tip and tail are away from this axis. The further away, the further they travel, and the more pressure against the snow. The same with straight skis, but the tip and tail are closer to the axis, so they travel less, which is why it's harder to carve on them.

The other question recently in this thread is, can a platform in the snow support more pressure than the pressure used to create it? I don't see how it always can if the platform is an equal and opposite response to the ski against the snow, especially if we take into account that the edge angle is changing the amount of ski base in contact with the surface. I'm gonna say that whenever we increase, or change for that matter, the angle of the ski to the snow a new platform needs to be created because of this. This isn't a static thing though, and I see it as a dynamic situation with the pressure and edging constantly being managed to create and maintain the integrity of the platform. Maybe I'm wrong???

Later, Ric.
post #113 of 117
Quote:
Originally Posted by Rick
RICK REPLY:

The important points, however, are:

1) In very hard snow the platform will only increase in depth a minuscule amount, certainly not enough to accommodate the new shape the ski desires to assume. And:

2) The snow is of high enough integrity that it will not sheer.

Which when taken together, means the arc of the ski will not be altered. If you are finding that you CAN alter the arc of the ski, then one or both of the above are cannot be happening at the same time.

Quote:
Originally Posted by Rick
The force needed to cut can indeed be smaller than the force the resultant platform will support. Just as the force an ice climber uses to get a bite in the ice with his crampon can be smaller than the force that bite will subsequently support.
I agree with you that less force is required to cut into the snow pack, but the resistance to sheering of the snow at the given edge angle remains the key issue; one is still standing on the ski with only the resistance to sheer stopping the ski from sliding out.

There is always a sheer force applied when you are on edge. If the snow pack can support a higher force without sliding away, then you can (a) ski faster, (b) turn sharper, (c) be fatter .

This is one scenario -- Sheering happens:

If you apply more edge angle, then two things are happening: You have moved the center higher above the snow pack -- there is now less snow directly underfoot, and the force is directed more along the surface of the snowpack. This certainly happens on really hard snow, as the edges won't dig in further.

Both of these attributes promote center deflection : the center is on less snow than before, and the forces are directed even more towards the direction in which the snowpack will sheer. It's not just that there is MORE force, but that it is applied on LESS snow. Sheering at the center of the ski happens.

The second scenario -- No center deflection, but change of arc anyway.

How? This snow must be softer, allowing the tip and tail to press further into the snowpack as the edge angle increase, without the movement of the center of the center of the ski up and away.

The arc will change because the change of angle made the tips of the ski bite deeper. The ski tips now push into more snow, and like a toboggan, want to ride above it. So, the tip will deflect upwards changing the arc of the ski. Clearly, the snow is soft enough for this tobbogan effect to occur.

Rick is right, the quality of the snow matters, so center deflection will happen on some snow, and not on others. And to make matters worse, both tip deflection and center displacement can occur simultaneously in some conditions!

I don't really think that there is much disagreement in this thread. I do think BOTH tip deflection and center displacement happen.

What this implies to me is that skis should be very sharp tip to tail, to maximize the change of direction by tip deflection. I can't think of skiing by control of center displacement alone as too much is happening at the tip. And if the conditions are such that center displacement really is is the dominant feature in the change of arc, then the tip and tail better be sharp!

Cheers!
post #114 of 117
RicB

welcome to the discussion, or this subplot, started when someone claimed there was no sideways displacement in a good carve.

you wrote: "or if the rate of tipping is balanced with the speed or forward movement, the tip will respond to the pressure by bending more and tightening the arc but still keeping the entire edge engaged, which is the feeling I get when I sense my ski tip pulling me into the turn."

so something makes the tips engage more but doesn't change the ski shape? I don't undstand you here, can you elaborate?

I think you have to be careful applying laws of statics in dynamics; in a skiturn there is deliberate imbalance which results in the turn, although at the moment we don't seem to be able to finger exactly how! Regarding the platform, because the platform is created dynamically, why cant the ski's forward motion cut in deeper than it needs for merely holding its lateral displacement?

I still don't see how a ski without a sidecut can carve by the explanations above, but I'm sure it can, so although the sidecut helps enormously (the new ski carving revolution) something else must be happening to allow a carving ski to change its shape.
post #115 of 117
daslider: so something makes the tips engage more but doesn't change the ski shape? I don't undstand you here, can you elaborate?

Ric B: if the tip is bending more then the shape of the edge in the snow is changing right?


Daslider: I think you have to be careful applying laws of statics in dynamics; in a skiturn there is deliberate imbalance which results in the turn, although at the moment we don't seem to be able to finger exactly how! Regarding the platform, because the platform is created dynamically, why cant the ski's forward motion cut in deeper than it needs for merely holding its lateral displacement?

Ric B: Well we certainly have mechanics and physics don't we? I don't buy the imbalance concept myself. We apply cenntripetal force, or as it is clasiffied in our body, a motive force through muscle action that controls the ski and the snow interaction to change direction. As far as the platform goes, given the opposite and equal law, I don't really see how a platform can be created in a compressable medium that is greater than the force being applied. If I'm wrong, I would love to have someone spell it out for me.

Daslider: I still don't see how a ski without a sidecut can carve by the explanations above, but I'm sure it can, so although the sidecut helps enormously (the new ski carving revolution) something else must be happening to allow a carving ski to change its shape.

Ric B: I don't know in modern times if there was ever a ski made without sidecut. Straighter definetly. Even a few mm of sidecut will give more leverage to the ski tip. In keeping with the mechanical explanation, maybe a straight ski could carve due to that same priciple of leverage. Lacking sidecut it would seem that the weight or pressure being apllied to the ski would decrease in direct relation to the distance away from the gravity line of the CoM. This would have the effect of pushing the middle of the ski futher into the snow wouldn't it? Same thing is happening with the shaped ski but with a wider tip this changes what recieves the most leverage. The sidecut changes how and where we leverage the ski edge. Of course even a totaly straight ski (no sidecut) would probably have an upturned tip which would add some direction changing ability if the ski was tipped on edge. Ahh,,,what a conversation. All this assumes everthing else but sidecut is equal. We can add leverage to a certain area (tip or tail) of the ski, ect.

Thanks. Later, Ric B.
post #116 of 117
RicB sems to suggest the tip of the ski's upturned shape acts like a rudder when the ski is edged and tends to increase the turn's radius. BigE talks of a tobogganing effect which if the ski is edged makes the tip attempt to ride up and inwards so sharpening the turn. These ideas are quite similar in saying the tip's design is to turn. So if we combine this with the overall change in geometry of the ski which the boot displacing the midsection contributes, i.e. an increase of decamber or tightening of radius, do we have a reasonable explanation of the edged ski's tendency to turn irrespective of any rotation?

I like the idea of the toboggan very much. A straight schuss would otherwise result in the skis burying themselves in and down. If that ski is tipped it not only aquaplanes up, but also tends to aquaplane sideways leading from the tip. The skier's momentum via the boot resists this direction change and pushes the ski into a camber or arc, but following the lead set by the tips, more like waggons following the engine into a bend. This action via the feet does not actually wash out the middle of the skis as I previously suggested, but bends the ski into the radius being determined by the engagement of the tips (the hook up some call it), and this radius reinforces that turn shape. More tip, more turn which is what we knew all along!

Along with the fluff, the one useful conclusion for me from all this navel gazing is that it is misleading to get too preoccupied with talk of edges when it is always the base of the ski (even when only a tiny part of it) that detremines what happens. The sharpened edge corner may allow the initial purchase, but it is the base and the shape it assumes that effects the turn, which is why we can carve hardpack and powder, turkey or cream.
post #117 of 117

Bearing Fruit?

Yeah Daslider, I'm sure there are some, maybe many, who feel this conversation has little fruit to bear. Sometimes I wonder myself. I do find for my own clarification it is always good to separate the apparent from the real. Understanding the mechanics involved helps me understand the bio-mechanics involved, which leads me to a better understanding of technique and the skills blending needed for versatile teaching and skiing. At least I hope so. Thanks. Later, Ric B.
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