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# You can easily tighten a turn but can you do the opposite? - Page 2

Originally Posted by justanotherskipro

Hmmm...
That sounded a little harsh, which wasn't my intent TDK. All I'm saying is in reviewing how you create a turn you will find the answers. The impression of getting locked in a certain radius turn and not being able to tighten or lengthen the turn radius is a very real sensation. I think it would be safe to say we've all done this. I know this might sound simplistic but If you don't want to get "stuck" in that situation maybe the entry into the turn needs to be different.

Quote:
Originally Posted by justanotherskipro

Adjusting the skills blend mid-turn will immediately change the size and shape of turn but it requires us to be in a relatively balanced stance when we make those changes. When we're not relatively balanced we're painted in a corner and our options get limited to whatever recovery moves will get us back into a more balanced stance. We call this maintaining a dynamic yet balanced stance that will allow us to selectively access any of the skills at any point in any turn. Mind you I'm not suggesting we can jump back up a cliff, only that in the scope of a well balanced turn we should have the ability to change the size, shape, amount of skid / carve, etc.

With the small exception that your very last sentence of your great quote here above I would put in the "whishful thinking" department .
Quote:
Originally Posted by Rick

Can you produce a larger radius turn than that built in limitation in some manner?  You bet,,, by gently steering your edged skis away from the direction they want to turn as you go through the arc.

Did not know this was possible. I have to try it out before I can comment. IMO the natural radius only gets "overrided".
Here is a new drawing I made where I try to contrast the forces in the high C and in the belly of the turn, low C.

See how far away downhill of our feet our CoM is located in the left drawing. Also the turn forces have not yet built up in the high C and therefore there is a strong falling movement down towards the ground. In the right drawing as we have come arround to the belly of the turn our turning forces are much bigger and therefore there is a small moment trying to lift us up and down the hill. On a side note, check out how much lower our edge angles are in the right drawig! To increase our edge angles here we would need to "angulate". I can make a drawing of that later because it could shed some light on the inclination vs angulation discussion we have had going (helluva, note two legged skier ).
Quote:
Fundamental question: un-tip, how? My CoM is outside the BoS, inside my inside ski and Im "falling into the turn". Extending my inside foot will only move my CoM furnter away from my BoS further inside the turn (the most common misstake BTW). And note, in the direciton of gravity downhill. This is before apex offcourse. You cannot apply same mechanics before apex and after due to this little detail. Overlooked in my opinion. Sofar nobody agreeing with me

The only thing I can agree with you on is that if you keep entering your turns the way you like to do, "falling into the turn" by letting your body get ahead of your feet, then you have few to zero options to increase your turn size before the fall line. Which is why I said in my original post that you need to reevaluate how you enter your turns if you are having such difficulties enlarging your turn radius before the fall line. This is what every one else has been saying as well.

So if you want to accomplish what "you" say is impossible it will require some changes in your technique. It is only impossible if you refuse to embrace change, so if there is no change, there will be no new outcome. In other words if you keep on doing what you have been doing you will keep on getting the results you have been getting. I don't want this to sound harsh either, but this is your choice and not ours. Do you need to make changes? Only if you want to do the impossible.
Quote:
Originally Posted by tdk6

I agree, glide longer and maybe not as much early tipping? Your GS example is a good one, I double turn frequently very early before any serious tipping has taken place. But double turning is not like opening up the turn radius, its more like aborting the turn and then starting a new one.

It would likely be a combination of less inclination early in the turn, and less angulation later in the turn.

Double turning is a good point to bring up -- this is something I watch for in GS line development.  It's not a good thing, so if I see double turning, I'll do things like setting brushes between gates to mark a better line.  I think this could be considered opening up or lengthening the turn the way you're describing.
There's an exercise called the Funnel (also the Hourglass) where one performs a series of turns starting with a longer radius turn, then a little smaller radius turn, then a little smaller radius turn, etc., until you have a short radius turn; for Hourglass you continue the series by reversing that order until you have a LRT. In some PSIA divisions it's an L3 task for certification and many race programs use the same exercise with gates. Traversing or sideslipping will fail the task.
Quote:
Originally Posted by RicB

So if you want to accomplish what "you" say is impossible it will require some changes in your technique. It is only impossible if you refuse to embrace change, so if there is no change, there will be no new outcome. In other words if you keep on doing what you have been doing you will keep on getting the results you have been getting. I don't want this to sound harsh either, but this is your choice and not ours. Do you need to make changes? Only if you want to do the impossible.

Maybe everybody else needs to ramp up their skiing quite a bit .
Quote:
Originally Posted by nolo

There's an exercise called the Funnel (also the Hourglass) where one performs a series of turns starting with a longer radius turn, then a little smaller radius turn, then a little smaller radius turn, etc., until you have a short radius turn; for Hourglass you continue the series by reversing that order until you have a LRT. In some PSIA divisions it's an L3 task for certification and many race programs use the same exercise with gates. Traversing or sideslipping will fail the task.

Ha, here we have it, L3 task. We are getting closer.... except offcourse if we are strictly talking L3 level. I migth not be there yet according to many here, actually quite far I have read between the lines but I have no such ambitions. Simply want to know if others experiance the same difficulty as I do with the task at hand. And also finding any theoretical explanation how it could be done. Task is quite smple, you are inclining and all of a sudden you need to reverse inclination.

So, tell me Nolo. What is so hard about that drill? Do you think it has anything to do with my original Q? Its easy to tighten the turn but can you do the opposite....
TDK,

I agree with RicB here.  So long as you are falling into the turn, you're going to continue to fall into the turn, and await the forces after the apex to hold you up.

One definition of insanity is doing the same thing over and over and expecting different results...
What makes it hard seems to be planning ahead -- to not get stuck in the turn you're in (making you late for the next gate). It might be easier if you have a reference, such as slalom poles or cones, set with lots of offset at the start and then progressively more in the fall-line then progressively more offset (if an hourglass drill). Keep your eyes looking ahead and let your body do its thing to shape the next turn, i.e., don't over-think the task.
I think one thing that needs to be explored here a little more is the pure physics of a turn. Yes, we're talking about centrifugal force here there and everywhere, but it bears defining. Most people believe that centrifugal force is a force that pushes things outwards from the center of the arc or circle. In fact, centrifugal force is an inward force, that pulls the kinetic energy of an object towards the center of the circle, rather than allowing it to travel in a straight line, as a body in motion will do if unimpeded. Any time an object travelling in an arc is released from centrifugal force, it will travel in a straight line on a tangent from the arc previously being travelled.

That being said, our skis act as the lever which creates centrifugal force, and prevents our mass from travelling in a straight line. The amount of force created by that lever has to be at least equal, preferably exceed the amount of momentum which is to be placed into an arc. If at any point, the leverage on the ski is dropped below that threshold, the skier's mass will travel in a tangental straight line from the point leverage was lost. This can happen inadvertantly, when a skier loses an edge and goes flying into the woods. However, it can also be done intentionally, by reducing the angle of the lever. Therefore, reducing edge angle will stop the ski from turning, and allow the skier to widen the radius of his turn. If done by a skilled skier, lessening the edge angle can be done while the skier uses flexion to absorb the excess force and rotate his skis onto the new arc, therefore minimizing, (and if using the Force) eliminating a sideslip or a skid.

Another method which may work, although I have not tested it on snow yet... Utilizing fore/aft balance adjustment to change the arc of the ski. If a skier moves aft on his skis, the amount of pressure being placed on the tips of the skis will be reduced, therefore lessening how much the ski is flexed. This would naturally cause the ski to travel on a longer radius. I'm theorizing this because I know that a few years ago, I wouldn't move my weight forward enough into the turn, and I would find myself with my skis running away from me, more down the fall line than I would have liked.
Quote:
Originally Posted by BigE

TDK,

I agree with RicB here.  So long as you are falling into the turn, you're going to continue to fall into the turn, and await the forces after the apex to hold you up.

One definition of insanity is doing the same thing over and over and expecting different results...

If the cue "falling into the turn" doesent suit you then you can try to think of something else. Anyway, as you start your new turn you extend your legs and project your body into the turn. You should know how it works. If you dont do this you will never be able to carve properly. If you only skid or steer at low or intermediate level with no intentions of going fast then its ok but for advanced level skiing and big angles you need to create some edge-angles and the only way of dooing that is by placing your CoM way outside your static BoS into the turn and dynamicly balance using the centrifugal force and your edge hold for. Read jasp posting I gave thumbs up for. However, if you are not depending on tipping for turning this topic may seem hard to grasp. My question is how to widen the arc once you commit to the turn. Nobody has sofar come up with a convincing explanation. Just like I said in my opening posting, advanced skier claim this is easy to do. Im still not convinced. In fact, sofar I have not gotten any input that would support it would be easy. Or even possible. Prove me wrong. Draw a diagram if words do not come easily.

Your comment of insanity.... I cannot see any connection to the discussion. Why do you think something we discuss in this thread is aiming to "do one thing over and over and expecting different results"? Can point me to it?
Quote:
Originally Posted by freeski919

I think one thing that needs to be explored here a little more is the pure physics of a turn. Yes, we're talking about centrifugal force here there and everywhere, but it bears defining. Most people believe that centrifugal force is a force that pushes things outwards from the center of the arc or circle. In fact, centrifugal force is an inward force, that pulls the kinetic energy of an object towards the center of the circle, rather than allowing it to travel in a straight line, as a body in motion will do if unimpeded. Any time an object travelling in an arc is released from centrifugal force, it will travel in a straight line on a tangent from the arc previously being travelled.

That being said, our skis act as the lever which creates centrifugal force, and prevents our mass from travelling in a straight line. The amount of force created by that lever has to be at least equal, preferably exceed the amount of momentum which is to be placed into an arc. If at any point, the leverage on the ski is dropped below that threshold, the skier's mass will travel in a tangental straight line from the point leverage was lost. This can happen inadvertantly, when a skier loses an edge and goes flying into the woods. However, it can also be done intentionally, by reducing the angle of the lever. Therefore, reducing edge angle will stop the ski from turning, and allow the skier to widen the radius of his turn. If done by a skilled skier, lessening the edge angle can be done while the skier uses flexion to absorb the excess force and rotate his skis onto the new arc, therefore minimizing, (and if using the Force) eliminating a sideslip or a skid.

Another method which may work, although I have not tested it on snow yet... Utilizing fore/aft balance adjustment to change the arc of the ski. If a skier moves aft on his skis, the amount of pressure being placed on the tips of the skis will be reduced, therefore lessening how much the ski is flexed. This would naturally cause the ski to travel on a longer radius. I'm theorizing this because I know that a few years ago, I wouldn't move my weight forward enough into the turn, and I would find myself with my skis running away from me, more down the fall line than I would have liked.

Great posting here. You get      five thumbs up for excellet attitude and approach. But I would like even more physics. BTW, Im glad you pointed out the weight transfer. Ive been waiting for it to come up. But that has other bad influences on your skiing and I dont think its a very usefull technique: accelleration and out of balance .
TDK,

First of all, if you are free-falling into the center of the turn that way, then actually you will not be well served to widen your turn through any means, even if its possible, because then it will take longer for you to regain your balance back.  If you are weightless, there is very little you can do and since you're hardly pressuring your skis at that point they aren't going to do much either.

Untipping is mainly all that is required.  More edge angle means tighter arc, less edge angle means wider arc.  If you untip past the critical edge angle then the ski will begin to slip sideways too and to also unbend itself.

I would say that if you are carving you can also shift your weight back a bit and that may have the effect to unbend the shovel a bit and widening your turn shape as you go.
Regarding pivoting for this purpose....I remain silent for now..
Edited by borntoski683 - 11/6/09 at 12:45pm
Quote:
Originally Posted by tdk6
If you only skid or steer at low or intermediate level with no intentions of going fast then its ok but for advanced level skiing and big angles you need to create some edge-angles and the only way of dooing that is by placing your CoM way outside your static BoS into the turn and dynamicly balance using the centrifugal force and your edge hold for. Read jasp posting I gave thumbs up for. However, if you are not depending on tipping for turning this topic may seem hard to grasp. My question is how to widen the arc once you commit to the turn. Nobody has sofar come up with a convincing explanation.

I've been following this thread, and at first I thought the question was silly -- of course you can! -- but the last few posts seem to have clarified the problem.

I'd have to think about the physics a little more, but it does seem to me that it would be very difficult to 'unincline' in the beginning/middle of a turn.  It's a 'pull yourself up by your bootstraps' conundrum.  Short of reaching out and pushing off the snow, there's nothing to pull you out if you're balanced against the forces of the turn.  (Once you get below the fall line, gravity is pulling you at least partially in that direction, so you have some help.)

If your skis are bent more than their natural radius (from, e.g., pressure on the tips), you should be able to unbend them by changing pressure or reducing any extra lateral force you're putting on them.  If you're at the 'maximum' radius already, you need to reduce the edge angle directly or break them out of their carve.  The problem is that if you're really balanced completely against the skis by pure inclination, increasing the turn radius *should* just cause you to fall further inwards (again, nothing for you to push against, and above the fall line gravity is pulling you into the turn.)

The only real solution I've thought of in the last 5 minutes is to bend your knees and let the centripetal acceleration 'push' you.  That should move you further to the outside, and you could get into a less inclined position with a lower edge angle.  The physics seem to be there, but I've never tried that move.

The better solution in practice is probably to start with some angulation, rather than pure inclination.  Then you can unangulate (disangulate?) to reduce the edge angle on the skis directly without upsetting your balance.
Quote:
Originally Posted by Matthias99

I've been following this thread, and at first I thought the question was silly -- of course you can! -- but the last few posts seem to have clarified the problem.

I'd have to think about the physics a little more, but it does seem to me that it would be very difficult to 'unincline' in the beginning/middle of a turn.  It's a 'pull yourself up by your bootstraps' conundrum.  Short of reaching out and pushing off the snow, there's nothing to pull you out if you're balanced against the forces of the turn.  (Once you get below the fall line, gravity is pulling you at least partially in that direction, so you have some help.)

If your skis are bent more than their natural radius (from, e.g., pressure on the tips), you should be able to unbend them by changing pressure or reducing any extra lateral force you're putting on them.  If you're at the 'maximum' radius already, you need to reduce the edge angle directly or break them out of their carve.  The problem is that if you're really balanced completely against the skis by pure inclination, increasing the turn radius *should* just cause you to fall further inwards (again, nothing for you to push against, and above the fall line gravity is pulling you into the turn.)

The only real solution I've thought of in the last 5 minutes is to bend your knees and let the centripetal acceleration 'push' you.  That should move you further to the outside, and you could get into a less inclined position with a lower edge angle.  The physics seem to be there, but I've never tried that move.

The better solution in practice is probably to start with some angulation, rather than pure inclination.  Then you can unangulate (disangulate?) to reduce the edge angle on the skis directly without upsetting your balance.

You give the thumbs up new meaning. Excellent posting. Brilliant out of the BoX thinking. This is exactly what I have been bogging my mind over for many years now. Ever since carving skis came along and it seemed to be very hard for people to avoid crashing into each other while carving. Many reasons offcourse but most people that crashed into each other had the same experiance, they saw it happening but they could not brake out of the turn. The reason for this is pritty simple. Its pure physics. You are in balance only because your skis are turning. If skis stop turning you balance is gone. But its not the fact that its hard, if not impossible, to widen the turn as easily as tightening it that upsets me, its peoples attitude. Glad you took the time and gave it some thaught.
Quote:
Originally Posted by tdk6

But you cannot release a turn at any moment in time. You can only release a turn when your released mass will not be drawn to the ground by gravity. For instance if you are at apex like in the diagram above, how do you lift your CoM up and vault it over to the outside of the turn using ILE?

Tdk6,

I would offer a very different take on what has been describe above.

First (to be clear) Centrifugal Force is an outward force - the force pulling outward on the sling as you twirl a rock around before releasing it.  Centripetal Force is an inward force - the force pulling the rock toward your hand, or the force holding the skier inside a turn.

If a skier is on flat terrain with their CM inclined too far inside a given radius turn for the given speed then they will fall over to the inside.  No question about this under normal circumstances.  But regular skiing is chock full of circumstances (context) well outside this simple scenario.

First, as a skier 'falls' to the inside they will automatically drag their degree of edging-angle with them.  As the ski tips further... (Assuming Carving): The ski will increasingly carve a tighter turning radius and thereby 'auto-correct' at least part of the original imbalance.  (Assuming Skidding): The tipping ski will edge more at Tip, Tail and Midpoint creating greater BoS friction and thereby force a slightly tighter radius turn (especially with shaped skis).  Greater BoS friction against lateral travel will help hold the skier upright as will the tighter radius caused by shaped skis dragging more.

In both carving and skidding, our tipping over (as we fall inside) will cause the skis to help us out some degree on their own.  If we're not too far out of lateral balance, it may be enough to keep us upright.  Also, as we begin to topple over, most of us will instinctively articulate our body to keep ourselves upright, thus unconsciously angulating even more - which in turn tips the skis further, which increases the effects described above (it's a recursive process).

Getting off the flat terrain we encounter a new geometric savior: Relative slope angle.

As we complete a turn past Apex we needn't do anything to increase our edge-angle with the slope because the relative slope angle is changing in relation to us (even if we hold a static skier body angle).  The steeper the slope, the faster this relative difference between slope angle and edge angle is increasing at a given speed.

Further, since we're going downhill we tend to pick up speed (this is true even above Apex).  If we're 'in lateral balance' for a given edge-angle at current speed, we will soon be ejected (to the outside) as we pick up greater speed if we merely hold that same edge-angle.

No ILE, no OLR, no Flexion or Extension is needed to be ejected from a typical turn so long as we're not too far out-of-balance to the inside.  (Flexing and Extending can augment things, but are not needed.)

On the matter of reducing edge-angle to increase turn radius... that will actually be counter productive if we're already slightly out of balance to the inside.  Releasing edge angle will only allow our BoS (skis) to travel a bigger radius and will not improve our lateral balance situation - we'll either fall further onto the inside leg - or fall over to the inside of the turn.

This is where earlier discussions of 'counter-steering' come into play.  If we momentarily tip the skis *more* (very briefly) then our CM will be ejected to the outside enough to allow reducing edge-angle safely (because our CM will be now be tracking a path more appropriate to the larger radius our skis will soon travel).

.ma
TDK,

You keep insisting that toppling/falling of whatever word you use is necessary to start a dynamic turn.  That's where the problem lies.  So long as you're driving the turn by the momentary "out of balance" state, then you are right -- you cannot release until after the skis have caught you again.

Trying to find a mechanism to increase turn radius after you've "committed" (another word for falling/toppling/projecting/extending inside) is insanity.
Quote:
Originally Posted by BigE

TDK,

You keep insisting that toppling/falling of whatever word you use is necessary to start a dynamic turn.  That's where the problem lies.  So long as you're driving the turn by the momentary "out of balance" state, then you are right -- you cannot release until after the skis have caught you again.

Trying to find a mechanism to increase turn radius after you've "committed" (another word for falling/toppling/projecting/extending inside) is insanity.

Almost insanity.  You can always step up on the uphill ski, just like GS skies did in the old days before modern skidecut skis, stivots, etc.
Matthias99, good thinking. Angulation. As you angulate you bring your hips into the turn and you keep your upper body more upright. Very simply put, you keep your CoM put but you increase edge angle. This will tighten your turn radius and increase the centrifugal force. A result of this will be that you are not in balance anymore, you un-tip. But now you are tightening your turn radius and you are untipping. That is a very good setup for a human cannonball. Or tearing your knee ligaments. More tipping is the only right move then and there. And that is closing the radius even more. At some point you will override your ski turn radius or edge angle and brake out of the turn and skidd. But is this a controlled way of widening the turn: tip more, higher edge angles, more pressure, tighter turn radius resulting in skidding and wider turn radius?
Quote:
Originally Posted by BigE

TDK,

You keep insisting that toppling/falling of whatever word you use is necessary to start a dynamic turn.  That's where the problem lies.  So long as you're driving the turn by the momentary "out of balance" state, then you are right -- you cannot release until after the skis have caught you again.

Trying to find a mechanism to increase turn radius after you've "committed" (another word for falling/toppling/projecting/extending inside) is insanity.

Right on the dime. Anybody else want to come and stand on my side of the fence  ?
Quote:
Originally Posted by quant2325

Almost insanity.  You can always step up on the uphill ski, just like GS skies did in the old days before modern skidecut skis, stivots, etc.

And SL skiers.... but not in the first phase of the turn.
Quote:
Originally Posted by borntoski683

TDK,

First of all, if you are free-falling into the center of the turn that way, then actually you will not be well served to widen your turn through any means, even if its possible, because then it will take longer for you to regain your balance back.  If you are weightless, there is very little you can do and since you're hardly pressuring your skis at that point they aren't going to do much either.

Quote:
Originally Posted by michaelA

Tdk6,

I would offer a very different take on what has been describe above.

First (to be clear) Centrifugal Force is an outward force - the force pulling outward on the sling as you twirl a rock around before releasing it.  Centripetal Force is an inward force - the force pulling the rock toward your hand, or the force holding the skier inside a turn.

If a skier is on flat terrain with their CM inclined too far inside a given radius turn for the given speed then they will fall over to the inside.  No question about this under normal circumstances.  But regular skiing is chock full of circumstances (context) well outside this simple scenario.

First, as a skier 'falls' to the inside they will automatically drag their degree of edging-angle with them.  As the ski tips further... (Assuming Carving): The ski will increasingly carve a tighter turning radius and thereby 'auto-correct' at least part of the original imbalance.  (Assuming Skidding): The tipping ski will edge more at Tip, Tail and Midpoint creating greater BoS friction and thereby force a slightly tighter radius turn (especially with shaped skis).  Greater BoS friction against lateral travel will help hold the skier upright as will the tighter radius caused by shaped skis dragging more.

In both carving and skidding, our tipping over (as we fall inside) will cause the skis to help us out some degree on their own.  If we're not too far out of lateral balance, it may be enough to keep us upright.  Also, as we begin to topple over, most of us will instinctively articulate our body to keep ourselves upright, thus unconsciously angulating even more - which in turn tips the skis further, which increases the effects described above (it's a recursive process).

Getting off the flat terrain we encounter a new geometric savior: Relative slope angle.

As we complete a turn past Apex we needn't do anything to increase our edge-angle with the slope because the relative slope angle is changing in relation to us (even if we hold a static skier body angle).  The steeper the slope, the faster this relative difference between slope angle and edge angle is increasing at a given speed.

Further, since we're going downhill we tend to pick up speed (this is true even above Apex).  If we're 'in lateral balance' for a given edge-angle at current speed, we will soon be ejected (to the outside) as we pick up greater speed if we merely hold that same edge-angle.

No ILE, no OLR, no Flexion or Extension is needed to be ejected from a typical turn so long as we're not too far out-of-balance to the inside.  (Flexing and Extending can augment things, but are not needed.)

On the matter of reducing edge-angle to increase turn radius... that will actually be counter productive if we're already slightly out of balance to the inside.  Releasing edge angle will only allow our BoS (skis) to travel a bigger radius and will not improve our lateral balance situation - we'll either fall further onto the inside leg - or fall over to the inside of the turn.

This is where earlier discussions of 'counter-steering' come into play.  If we momentarily tip the skis *more* (very briefly) then our CM will be ejected to the outside enough to allow reducing edge-angle safely (because our CM will be now be tracking a path more appropriate to the larger radius our skis will soon travel).

.ma

Im gonna give you three thumbs up. Thanks for your great input. Read this quote folks, its excellent stuff. Im glad you picked up on the counter steering consept. Acutally the only move we instinclty can do safely is to tighten the turn. This will then give us several options.

I can see a change in general opinion here .
But, if I do NOT *commit* to move strongly inside the turn, I can do anything.

Here is a similar comment, obviously false: expert skiers can slow down at *any time*.  *Any time* is the problem.

What if I've committed to entering the fall-line?

Well "committing" to do anything means that you can't do other things.  If I'm commited to my wife I can't "do" some other things.

If I wish to perform a move and I am *committed* to completing it (like toppling/extending etc etc..), then I have committed to tighten the radius.  Once I've committed to tightening turn radius, does it make sense to point out that I cannot increase the turn radius at that exact moment?????

No of course not.  These are just word games.
Quote:
Originally Posted by BigE

But, if I do NOT *commit* to move strongly inside the turn, I can do anything.

Here is a similar comment, obviously false: expert skiers can slow down at *any time*.  *Any time* is the problem.

What if I've committed to entering the fall-line?

Well "committing" to do anything means that you can't do other things.  If I'm commited to my wife I can't "do" some other things.

If I wish to perform a move and I am *committed* to completing it (like toppling/extending etc etc..), then I have committed to tighten the radius.  Once I've committed to tightening turn radius, does it make sense to point out that I cannot increase the turn radius at that exact moment?????

No of course not.  These are just word games.

Good posting BigE. But the general opinion is that they can. This thread proves it. I dont think its only word games, there are a lot of missconseptions. This is one of them.
Actually this statement is true for all skidded parallel skiing because all parallel skidded turning involves tipping body inside the turn. In a wedge this is not true and that is what makes the wedge a pritty good technique for beginners. Since they never put their CoM outside their BoS they can at any time pressure whichever ski. Opening up a stem is also a good way to widen the BoS in the midst of a turn and change the radius of your turn. So all parallel skiing when skidding involves tipping the body into the turn but its often just a thad which makes recovery moves easier.
Quote:
Originally Posted by tdk6

Here is a new drawing I made where I try to contrast the forces in the high C and in the belly of the turn, low C.

See how far away downhill of our feet our CoM is located in the left drawing. Also the turn forces have not yet built up in the high C and therefore there is a strong falling movement down towards the ground. In the right drawing as we have come arround to the belly of the turn our turning forces are much bigger and therefore there is a small moment trying to lift us up and down the hill. On a side note, check out how much lower our edge angles are in the right drawig! To increase our edge angles here we would need to "angulate". I can make a drawing of that later because it could shed some light on the inclination vs angulation discussion we have had going (helluva, note two legged skier ).

So TDK, Where's the force vector for our forward movement? From what I see you only have the lateral plane represented in this drawing. Which suggests to me that you are not seeing our trajectory as relevent to this discussion. That is exactly why the whole idea of a balanced stance seems so impossible. Look down from above the skier and you will see a force vector diagonal to the direction of travel. Add that to your model and the model is more complete.

To this point the rock on a string model has been mentioned but only in the accelerated POV of the rock. The string pulling the rock inward along a radius of the circle and the rock resisting that pull by pulling back out along a radius of the circle. Centripital and centrufugal forces having a tug of war and trying to accelerate the skier in the lateral plane. So far so good.
But what about the forward movement of the rock?  Where's that coming from? To find out we need to change perspectives to see the arm moving to create the force acting along a tangent to the circle that moves the rock forward. Plotting the new resultant of sum of forces reveals a vector that is diagonally inward and forward but not along the radius of the circle. That vector and the forces it represents should help to explain that reducing the inward pull would open the radius of the circle the rock is scribing. The rock doesn't need to do anything to open this radius, what changed is the inward acting forces and when the outward acting forces are greater the rock moves outward and the raduis of the circle got bigger.
Transfer this to the skis by thinking about adjusting the inward acting forces until the outward acting forces cause you to move outward. this far from a complete model of a ski turen but it does include one more key component that was missing. Doe this make any sense?
Edited by justanotherskipro - 11/6/09 at 4:39pm
I think TDK is thinking about a particular situation where he has become very committed to the downhill turn and cannot extricate himself from it without moving the skis further downhill than his body because the centrifugal force at the speed he is skiing just isn't there.  We've all had to quickly move our feet  over avoid trouble on occasion. (sometimes only had time to move one into a stem while lifting the other)

BTW the red line looks like it's intended to be centrifugal force, and the green gravity, but if so, the drawing is a bit off.  The red line doesn't change length if speed and radius remain the same, and the turn takes place in a plane parallel to the slope (red parallel to slope) and the change occurs because the net force is the sum of green and red, which will point more to the outside on the downhill side of the turn. (green arrow has a component pointing in same direction as red arrow on downhill side and subtracts from it on uphill side)
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