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# Angulation vs. Banking - Page 4

You want angulation? THIS, my friends, is angulation. (My friend Steven outside of my dorm)
Bummer about the skiing, BTS--I'd be grouchy too!

You are correct about the force vectors, which is why I mentioned that at least some degree of ankle tension (angulation) is generally needed, at least in hard conditions.

But angulation is not necessarily needed to "distribute your weight to the outside ski"--the forces of the turn will do that, unless you incline too far into the turn, which can be corrected either by tipping the upper body out (angulation) or by inclining less.

You certainly can angulate without inclining. We do it all the time when standing still or traversing across a steep hill.

Quote:
 "there should always be some amount of angulation" "Inclination without angulation is what I hear everyone here calling "banking" and that is flawed skiing."
Statements like these carry no weight until you explain "why?"

Quote:
 anyone who thinks that the faster you go, the more you need to "bank" ....is BUNK.
I have explained why this is incorrect. Edge angle is a function of angulation + inclination. Increase one and, if you want to maintain the same edge angle, you must decrease the other. Balancing at higher speed in a given turn requires greater inclination. The math is easy.

Come on, BTS--This is an instructional forum. Get your facts right. If you're going to state opinions, you owe readers some explanations. You're entitled to your opinions, of course, but if you want to convince anyone else to share them, educate us--give us some reasons, some basis for those opinions. Why is banking inherently flawed skiing? Why "should" we always angulate (beyond the minimum, as discussed)?

Best regards,
Bob Barnes
Great, thanks for the scolding. I will bite my tongue
Sorry, BTS--scolding not intended! I'm not trying to be harsh, just trying to keep the information real. Sorry if it comes across otherwise!

And I'm not suggesting that you shouldn't express your opinions--or that I don't respect them. But to make them convincing and give them some weight, let us know how you arrived at them. Help us learn!

Best regards,
Bob
Bob,

I realize you are a high ranking person in the PSIA community. With all due respect, this issue has been debated and discussed to death about a thousand times on this forum and I have spent far too much time already writing long epistles on this subject (and many others). All one has to do is do a search and will find many many posts on the subject.

All the best
BTS
Hah! Agreed--and I've been part of many of those discussions too. But the WWW's attention span is, unfortunately, brief, and it seems to suffer badly from short-term memory loss. So every discussion around here is brand new.

I tire of the need for repetition too, and I often find myself muttering "didn't we just discuss this?" But I still think that unsupported opinions can confuse more than enlighten, even if the support can be found buried in the archives somewhere.

I hope you get some snow, and a chance to enjoy it soon!

Best regards,
Bob
Bob, the pictures of the racers that you posted all showed racers ABOVE the gates at the top of the turn. Can we venture to guess what happened as the turn deveoped? I am thinking that the only skiers who continued the turn banked are the ones who also finished the turn on their backside. I suspect the reason you see racers in the position thatyou do at the top of the gate (especially in GS) is that they are not skiing arc to arc, and are often inserting a pivot at the top of the turn or letting the skis run straighter in order to maximize speed and tighten the arc once they hit that part of the turn. This is kind of a GS racing 101 movement due to the fact that this kind of skiing is not always arc to arc. Angulation is a function of balance and efficiency of moving from one turn to the next. If you want efficient transitions and balanced skiing angulation is a must at some point in the turn.
Later
GREG

http://www.youtube.com/watch?v=zF1kuBMuNIE - some of my GS carving that when paused at the top of every turn you can find a stacked position similar to what is demonstrated in your photos.
Quote:
 Originally Posted by HeluvaSkier Bob, the pictures of the racers that you posted all showed racers ABOVE the gates at the top of the turn. Can we venture to guess what happened as the turn deveoped? I am thinking that the only skiers who continued the turn banked are the ones who also finished the turn on their backside. I suspect the reason you see racers in the position thatyou do at the top of the gate (especially in GS) is that they are not skiing arc to arc, and are often inserting a pivot at the top of the turn or letting the skis run straighter in order to maximize speed and tighten the arc once they hit that part of the turn. This is kind of a GS racing 101 movement due to the fact that this kind of skiing is not always arc to arc. Angulation is a function of balance and efficiency of moving from one turn to the next. If you want efficient transitions and balanced skiing angulation is a must at some point in the turn. Later GREGhttp://www.youtube.com/watch?v=zF1kuBMuNIE - some of my GS carving that when paused at the top of every turn you can find a stacked position similar to what is demonstrated in your photos.
Rather than "venturing to guess" what happens later, I'd suggest checking the video available in a number of places, including youtube, some of which is already linked in this thread. But the basic dynamic you state of banking higher to developing angulation later is correct (though you'll see lots of exceptions including lots of banking well past the gate).

I agree with you in principle. Actually, the skiers in the third and fourth photographs (from the left) are below the gates, near the end of their left turns. I think that the extreme banking they show reflects an error, although both recovered to make the next turn. Here's another look, followed by the next three frames in the sequences (moving right to left):

In the second frame (from the right), you can see how hard the skier had to work to recover from being too far inside the turn--big lateral step and extension with his left leg to push himself back over his skis.

Here you can see that the skier set his edges with some angulation in the next frame (second from right), allowing allowing his skis to start carving back underneath him. As this happens, he throws his upper body up and over into the next turn, starting the cycle over again (third and fourth frames from right).

Both of these sequences reflect errors, in my opinion. The banking in these turns results from starting the turn with the upper body--both tipping and rotating (what Gurshman calls "leaning in"). But they are errors made by very good skiers! And it is an "error" similar to the White Pass Turn of Phil and Steve Mahre--done instinctively, not intentionally, that actually served their needs at the moment quite well indeed!

The other three skiers in my earlier post are above the gates, as you say, and I agree with your analysis of why they are banking. All good skiing movements serve a purpose, and the banking in those photographs is functional. It sets them up for balance, well inside their arcs of their skis, later in the turn when they engage their edges (with increased angulation) and rip carved finishes to their turns. Even so, the amount of angulation they employ is (usually) very subtle, compared with techniques of old. It is enough to get the job done, but no more than needed. I'll post some of those sequences too, if I can find the time.

Nice turns in that video clip, by the way!

Best regards,
Bob Barnes
Quote:
 Originally Posted by Bob Barnes/Colorado Here's an illustration of a skier who is deeply inclined for balance in a high-speed GS turn, with moderate angulation in his feet/ankles, knees, and hips, which provides the edge angle needed for the chosen turn radius. Note that he is both inclined and angulated. It is not an either-or thing! Best regards, Bob Barnes
Excellent. You know what you're talking about. I think BTS understands intuitively, but just can't get the physical model down.

Let's make a few simplifying assumptions to illustrate the main point: pure carving, no vertical acceleration (no compressions nor transitions)

In the picture above the force of gravity acting on the skier is directed down. A centripetal force acting on the skier causes him to accelerate around a curve at the radius dictated by the tipping angle of the skis and the sidecut radius of the skis. From the skier's viewpoint he would feel this centripetal force as a centrifugal force pulling him to the outside of the curve. The centrifugal force is equal to V^2/R times the skiers mass, where V is velocity and R is radius of the turn. To be in balance along the outside ski, the vector sum of these two forces must pass through the (inside edge of ) outside ski. (to add vectors, connect the scaled arrows tip to tail)

If you ski faster around the same radius turn, your weight does not increase, but the centrifugal force does. In order to make the net force pass through the outside ski you must move your cm closer to the snow. Without changing the turn radius, this can only be done by angulating less.

There is a limit however. Let's consider forces where the ski meets the snow. The combined centrifugal and gravity force, pushes in a direction from the cm. A vertical (up) force is applied by the edge. The other force is applied normal to the skis surface.

With angulation, the cm is above the normal vector, and the edge is able to apply some upward force so that the combined vertical force due to the normal force and the vertical force at the edge add up to the skiers weight. This is a good thing; the edge is being pushed a bit sideways into the snow.

With banking, the normal force aligns with the combined centripetal and weight force. and the entire skier's weight is resisted by the vertical component of the normal force. There is no sideways (towards the edge) force keeping the ski in it's groove. There is no sideways force at all keeing the edge on the snow. Beyond banking, the skier's weight would be exceeded by the vertical component normal force, the ski will leave it's groove and you have lost the edge.

Hi Ghost--perhaps this will help:

Best regards,
Bob
That's a great diagram, Bob. Now all we need is one where you can grab the cm with the mouse and move it to the right increasing the centrifugal force to simulate going faster through the same turn. Eventually a point will be reached as the cm passes the normal vector to the plane of the ski where the resultant force pushes the ski out of its groove.
It is my understanding that you inclinate at the top of the turn and progressively add angulation and leveling of the shoulders as the turn progressives so that your are fully angulated and level shouldered at the gate depending of course on the amount of direction change tneeded for the following gate.

### Two kinds of "edging"

Quote:
 Eventually a point will be reached as the cm passes the normal vector to the plane of the ski where the resultant force pushes the ski out of its groove.
True, but that is more a function of the angle of the ski in relation to the body than to the angle of inclination of the body into the turn. Indeed, your statement hits at the heart of what angulation is all about! Angulation is what keeps the ski at an acute angle to the line of action, regardless of the angle of the line (which is the angle of inclination). As long as the ski is tipped to an acute angle to the line of action, the force will drive the ski into the snow surface. Something as subtle as relaxing the ankles can cause the ski to flatten sufficiently that it releases and slips--no matter how high its angle on the snow.

You've opened an important new can of worms here, still quite relevent to the discussion of inclination and angulation. To understand edging, it is important to realize that there are two ways to measure edge angle, that they serve two very different purposes, and that we must control both of them independently, at the same time, constantly.

The two ways to measure edge angle are
1. Edge angle on the snow surface.
2. Edge angle in relation to the forces applied to the ski (the resultant force, or line of action, in my illustration above).
Edge angle on the snow determines how tight an arc the ski will bend into when pressured into "reverse camber," and thus how tight a turn it will carve cleanly. In the following animation, note that tipping the ski higher will cause it to have to bend more deeply under pressure before its edge contacts the hard surface.
Reverse Camber, a function of edge angle on the snow.

Edge angle in relation to the force applied determines whether or not the ski holds and carves or releases and skids. Ghost alludes to this concept, sometimes known as "critical edge angle," in his post above. Here's another animation that shows this principle:
"Critical Edge Angle," a function of edge angle to the force applied.

Note that, as Ghost suggests, as soon as the ski flattens boyond 90 degrees, the force applied tends to push it out of the groove it cuts into the snow, causing it to release and slip. And this is true regardless of the angle of the force (the resultant force, aka. line of action, aka. degree of inclination), and regardless of the angle of the ski on the snow
.
I hope these animations help explain these important but subtle concepts!

Ghost--please refrain from raising any more excellent points. I need my life back!

Best regards,
Bob Barnes
Quote:
 Originally Posted by Bob Barnes/Colorado Some knowledgeable skiers prefer to think of inclining the feet and lower legs as the edge control movement, and angulation as the movements of the upper body in the other direction to balance or counterbalance--an equally accurate way to look at the concepts. No conflict, as long as we understand the different effects of creating angles and moving the center of mass and remain consistent in our use of the terms. Beyond that, it's semantics and personal preference.
If you are one of those knowledgeable skier who see it that way, same thing happens, except as you increase the speed for the same tipping angle (and turn radius), the ski maintains the same angle to the snow and it's the red arrow that attacks at a new angle to drive the ski out of it's groove.

### Warning--now we're getting technical!

Quote:
 It is my understanding that you inclinate at the top of the turn and progressively add angulation and leveling of the shoulders as the turn progressives so that your are fully angulated and level shouldered at the gate depending of course on the amount of direction change needed for the following gate.
Atomicman--this is a common and almost universal understanding, a time-honored bit of "conventional wisdom" that describes the intent and technique of many good skiers--and the advice of many instructors. However, I suggest we revisit this idea with a critical eye. I think it is flawed and, in fact, causes many problems.

(Warning--this discussion will get fairly technical. Proceed only when ready and in the mood!) The animations above help illustrate the problem, and here's another one to go with the previous force-vector diagram:

Gravity and Centrifugal Forces in steep terrain

This illustration shows the same forces of gravity and centrifugal force and the resultant (sum of both of them) as first image, as they work throughout a turn on steeper terrain. Note that where the blue dotted line is outside the arc is the part of the turn where the forces combine to pull us out of the turn and we must resist them, while using those forces to bend the ski and make it carve. Where the blue dotted line is inside the arc, the forces pull into the turn, and it is difficult at best, to bend the skis and carve.

Think about what happens in a turn, especially on a steep pitch. At the top of the turn, the hill tilts the same direction as our skis, reducing the edge angle on the snow. At the bottom of the turn, the hill tips the opposite direction from our skis, increasing the edge angle on the snow.

Furthermore, gravity pulls us constantly downhill (or at least, a component of it does, if you want to get technical). Therefore, at the top of the turn, gravity pulls us into the turn, reducing pressure on the skis. At the bottom of the turn, gravity pulls out out of the turn, increasing pressure. (See the white vector arrows in the illustration above.)

Further furthermore, speed typically increases progressively from the start of the turn as gravity accelerates us downhill. Increasing speed means increasing centrifugal force pulling us out of the turn. (See the red arrows in the illustration.)

So centrifugal force gains intensity and increasingly aligns with gravity throughout the turn, dramatically increasing the force (resultant) we must resist to avoid skidding out of the turn. (See the blue arrows.)

Meanwhile the hill angle, as described above, progressively causes the edge angle on the snow surface to increase. This causes the ski to bend into an ever tighter radius, trying to carve an ever tightening arc, elevating centrifgul force even further.

Combine these things with the progressive increase in angulation that you described increases edge angle even more through the turn, causing the skis to want to carve an ever tightening spiral ("fish-hook shape") rather than a round arc, still further increasing centrifugal force as the radius tightens and speed increases. And of course, inclination must also increase through this turn to balance against these increasing forces, even still further increasing edge angle!

Wow! It's no wonder that many skiers find themselves "blowing out" at the bottom of the turn, with all these forces gaining strength and ganging up on us all at once!

So consider this alternative, which is the opposite of your understanding of progressively increasing angulation (and thus edge angle) throughout the turn. What if you developed a lot angulation early in the turn, tipping the skis quickly to an edge angle (on the snow) that would cause them to start carving your intended (round, for the sake of argument) arc as soon as you could get enough pressure on them to bend them to reverse camber. Then, as the hill angle (vs. your skis) increases, and your inclination increases to balance at growing speed, you progressively decrease your angulation. This movement will help keep your skis at a more constant angle on the snow through the turn, carving a consistent radius, and at least somewhat mitigating the naturally increasing forces at the bottom of the turn. The outcome: rounder, more cleanly carved turns, with far less extreme changes in pressure and much less likelihood of blowing out at the bottom of the turn.

Here's one final animation in which I tried to illustrate what I have just described. Note that the quick and early angulation, which progressively decreases as forces and inclination increase through the turn. It also shows how hill angle subtracts from edge angle on the snow at the top of the turn, and adds to it at the bottom, and it shows the edge release as skis flatten beyond "critical edge angle" to start the turn. Lots of stuff in here--I'm not sure it works, but here it is, for what it's worth:

Progressive Banking (de-angulation)

Food for thought! I'm not suggesting that this "progressive banking" is "the right way to ski," but it clearly shows that it is an important technical option, and that controlling edge angle is a far more complex activity than it may appear. Every movement has an effect, and "the right way" means exploiting all possible movements as skillfully and purposefully as possible in any situation, in order to achieve whatever the desired outcome may be.

Best regards,
Bob Barnes
And now I am definitely outta here! I'll be back. . . .

WOW!!! I have to digest that. the theory makes sense but when I look at Wc racer montages it does not look like this is what is happening.
It makes good sense to me.

The line choice dictates how much inclination is needed and where the cm needs to be to get pushed down the hill and around the gates (or obstacles). That line choice may include very different shapes for many reasons. For example, if the goal is speed, getting as much vertical as soon as possible may delay the bulk of turning out of the fall line until later (but not so late that it can't be made). Aiming straight down asap may cause an earlier turn into the fall line. Also, the cm does not always follow the exact same path as the skis, but gets moved down the quickest path while the skis get to where they need to be to push the cm down that path.

Like you said, Bob. It depends on intent. Put your skis and CM where and how you want them to do what you want done.

Looking forward to your diagrams with vertical accelerations taken into account. Let's talk about turning in compressions....naw, better not.
Bob,

A couple things.

1 - Your depiction of critical edge angle is not quite correct. Nobody skis with their skis 90 degrees to the snow. The critical edge angle is when the base of the ski is 90 degrees to the RESULTANT FORCE vector. The Resultant force vector is, as you explained, a result of gravity and centrifugal forces. However your diagrams are missing a key factor. In the first picture you show the front of the skier view with gravity pointing into the ground and Centrifugal forces going out to the side, with the resultant force being an angled direction, IDEALLY straight to the inside edge of the outside ski. It also depicts the skier on flat ground rather than a slope, but I'll get to that in a minute. Your next diagram shows how all these forces change during the turn(very cool diagram actually), but unfortunately it is only a 2D view and does not show the angle of the resultant force vector relative to the snow. Your claim is that the angle remains constant I guess.

I would say otherwise, the resultant force is not only increasing through the turn, but the angle of that resultant force is changing as well, which requires adjustment of the critical edge angle relative to the surface of the snow, if your goal is to ensure that you don't skid. This means for certain, the closer you get to the apex, the more edge angle you will need to avoid skidding. And further....

2 - I agree that people should develop early angulation as being closer to "ideal", but not really for the reasons you say. Big edge angles are not required in the top part of a turn because the centrifugal forces are very low(as you showed in your cool force picture). Its almost all Gravity at that point. However early angulation helps apply weight to the outside ski to make it bend, which will in turn help to build G forces, which will in turn help to bend the ski more, etc. Early angulation also helps to keep you from falling too much on your inside ski as your CoM topples to the inside of the turn.

3 - As you approach the bottom of the turn, the resultant force vector relative to the snow is actually much closer to parallel to the slope, since the snow is sloped closer to the same direction as gravity. You need another diagram that shows the first picture above on a slope at the bottom of a turn. In that situation the centrifugal and gravity forces are not pointing 90 degrees apart, but could be 40-60 degrees apart depending on how steep the slope is. The net resultant force will be much more unified and more pointing in a direction closer to parallel of the slope; and thus require a higher critical edge angle, not less and not the same.

4 - The reason skiers J hook is because they hold on to their turn too long, not because they have too much edge angle while turning. Its a timing issue. Some place between the apex and the end of the turn they should begin the process of transition, which again changes the resultant force vector and the critical edge angle requirements. The appearance of a J hook also happens because the top part of the turn for many skiers does not include much carving if any. A huge percentage of recreational skiers float through the top part and barely start engaging the edges at the apex. So no wonder they have to slam on the brakes through aggresive edging during the bottom portion and no wonder they often go too late before releasing to transition again. Instead of skiing from transition to transition, they are skiing from apex to late-transition.

5 - As Greg pointed out, Being angulated when you get to the last part of the turn puts you in a much better position to execute a clean transition into the next turn; then if you are banked inside.

6 - Angulation in and of itself changes the resultant force vector by moving the gravity arrow further out over the outside ski, which changes the angle of the resultant force(coincidentally in a way that reduces the critical edge angle requirement). Now there is a twist for you. Angulation actually lowers the critical edge angle requirement while raising edge angles at the same time. hmmmmm.
Quote:
 the theory makes sense but when I look at Wc racer montages it does not look like this is what is happening.
No, at least not in the extreme form that I described, at least not very often. But in fact, we do see the principles applied in World Cup racing, and have for some time. The emphasis on getting "early edge," the concept of getting "upside down" (which basically describes angulation and getting the feet uphill from the body at the top of the turn), the more subtle angulation in general, the idea of "retraction" turns that involve flexing and softening edge angles to reduce pressure through the turn completion, emphasis on shaping and carving turns earlier (in the upper half), and the obvious fact that great racers are able to hold and shape great turns on icy conditions where most skiers can't even stand up, all relate to the concept I have described.

Ultimately, as I suggested, it is not "a technique" that they either do or do not do, but a display of exquisite skill at applying all possible movements as needed, adapting them situationally, instinctively reducing pressure here, adding pressure there, and constantly controlling edge angle both in relation to the hill and to the "resultant force" for optimal ski performance.

Great racers are really, really good at going right to the limit, making turns as tight as possible and generating forces right on the edge of what their skis and their bodies and the snow conditions can withstand. So we still tend to see progressive angulation and edging to that limit, at which point they soften angles, absorb pressures, and start to release the turn.

And, of couse, we also see plenty of examples where the racer should have applied these principles more effectively, when they do blow out of the turn.

For our practical purposes, the "theory" is not something we should try to adopt as a "default technique," but something to be aware of and to play with and become familiar with. Practice both progressive edging (angulation) and progressive banking (de-angulation), and become acquainted with the different sensations and results they produce. It's really not a theory at all! Different movements are clearly possible, and they do produce different outcomes. Better skiing is simply about increasing our virtuosity at playing the instruments of our sport--our equipment and our bodies and the mountain--to produce whatever music we choose!

Best regards,
Bob Barnes
I think we need to reach consensus on the simple things before we can move on to more complicated things.

Consider Bob's first vector drawing, the one I quoted with the skier showing a fair amount of angulation and inclined at about 25 degrees to the snow, as a snapshot of a skier in the apex of a turn of a given radius on a horizontal surface. Now consider what the forces would be in that same turn at the apex, with the same radius but now going much faster. The skis will have the same tipping angle for the same radius, the horizontal arrow will be longer due to the greater centrifugal force, the vertical arrow will be the same length as the skier did not gain weight, and the cm will have to be further to the right so that the resultant force acting on the cm passes through the inside edge of the outside ski.
If the horizontal arrow is longer, then the critical edge requirement has changed and more edge angle will be required to avoid skidding. Critical edge angle is 90 degrees to the resultant force vector.

What I hear you talking about Ghost is about trying to find a way to get that resultant force vector redirected to your outside ski's inside edge. Yes, if you are going faster you will inclinate more. Otherwise you will not remain balanced on that outside ski's inside edge. You're still gonna need to angulate because even though the increased inclination has increased your edge angle, the increased speed has also increased your critical edge angle requirement. The crticial edge angle is not a fixed value based on radius at any speed.
In order to ski at the same radius, the tipping angle must be the same, even at the higher speed. Agreed?

As speed is increased, the critical angle for the angle at which the ski is tipped on edge is approached by the resultant force. At the point of pure banking the critical edge angle is reached. Attempting to go faster than that and balance on the outside ski results in going past banking and loosing the edge.
Interesting dilemna isn't it? If you go faster the critical edge angle requirement will increase, but you have a given turn radius you are trying to accomplish, except faster now. I guess that is why they make GS and downhill skis Ghost. ;-)
Attempting to explain it from your way of looking at it, I think, the tipping angle of the skis (though not changing as it depends on the turn radius being set) is a lot closer to the critical angle at the higher speed, you are angulating less. At the lower speed, you angulate more and the tipping angle is nowhere near the critical angle. When the critical angle = the tipping angle, you're banking and any little miscue will cause you to loose the edge.

Yes. That's why I have a quiver from SL to SG (edit: my sgs are a lot more like DH skis than modern sg skis). We sort of reached that conclusion already.... http://forums.epicski.com/showthread...ight=conundrum
Correction to point#6 above, angulation does not alter the resultant vector, it only alters the position of the skis relative to the CoM and relative to the resultant vector.
You guys talk a great game. But, enough talk! Time to put up some videos (like Heluva did) so we can see if you can walk the walk or just talk the talk.
Quote:
 Originally Posted by Ghost At the lower speed, you angulate more and the tipping angle is nowhere near the critical angle. When the critical angle = the tipping angle, you're banking and any little miscue will cause you to loose the edge.

No matter what speed you are going, if you don't want to skid you must always have the skis at the critical edge angle(or more), whatever that angle happens to be at any given moment in time.

At slower speeds the critical edge angle requirement is reduced. You frankly don't really need any more angulation going slow then you do going super fast. There may be other factors at play such as the wrong ski for the job,. This is why slower skiers go for SL sidecut skis so that they can turn sharper, going slower with less edge angles. There are other factors also at play such as how easily the shovel of the ski will bend.
Quote:
 Originally Posted by Max_501 You guys talk a great game. But, enough talk! Time to put up some videos (like Heluva did) so we can see if you can walk the walk or just talk the talk.
Excuse me Max, when did this turn into a pissing contest?
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