The outside ski to outside ski drill.

[LiquidFeet]

I'd like to see that too.

 

[Erik Timmerman]

I just came to post in this very important thread and say that today I was working with a client on Javelins and I discovered that I can do brushed ones cleanly with no ski touching and no pole touch. I think that turning the one leg against the other basically acts like counter rotation and on today's very hard surface that was enough to overcome the friction of the ski on the snow. Sorry Josh, no video, hopefully you will take me at my word on this one.

 

[LiquidFeet]

Here's my list of ways of making a non-carved/brushed turn on one ski that have been discussed in this thread.
Comments?

1. Counter-rotation will turn the ski if it is sliding with little grip on very firm snow.
2. Torque from the pole touching the snow can get the ski turning.
3. If the skier starts with an initial two-foot rotary push-off, then lifts a ski, that will get the turning started.
4. If the lifted ski's tip lightly contacts the snow, that can produce drag that will make the stance ski turn.
5. Forward pressure can dig the tipped shovel into the snow, and if the tail is light enough it will wash out creating a round turn.

 

[CalG]

Here's my list of ways of making a non-carved/brushed turn on one ski that have been discussed in this thread.
Comments?

1. Counter-rotation will turn the ski if it is sliding with little grip on very firm snow.
2. Torque from the pole touching the snow can get the ski turning.
3. If the skier starts with an initial two-foot rotary push-off, then lifts a ski, that will get the turning started.
4. If the lifted ski's tip lightly contacts the snow, that can produce drag that will make the stance ski turn.
5. Forward pressure can dig the tipped shovel into the snow, and if the tail is light enough it will wash out creating a round turn.

How about just the right amount of ski tipping that will generate sufficient turning inputs AND grip to counter the momentum that would continue a straight line?

 

[Magi]

Magi....do you have video of someone able to vary for and aft pressure so they can shape a turn with no edge lock, ski drag, or pole drag?

Nope! Not a frame. In all the situations where I could video "proof" of this I either:

Haven't remembered.
Haven't had the time to take it.
Haven't had a videographer.
Haven't had a camera.​

I respect many of the people who suggest this is impossible as skiers and educators quite a bit. I don't mean to imply anything about anyone's level of knowledge, talent, ability, or skill.

Either my explanation of how it happens and my attestation that I can do it sometimes and I ski with people who can do it basically on command (Examiners / ex-Demo teamers / Alpine Committee Members) is enough to convince you it can be done, or it isn't.

At the end of the day, I'm okay with agreeing to disagree.

 

[Jamt]

I just came to post in this very important thread and say that today I was working with a client on Javelins and I discovered that I can do brushed ones cleanly with no ski touching and no pole touch. I think that turning the one leg against the other basically acts like counter rotation and on today's very hard surface that was enough to overcome the friction of the ski on the snow. Sorry Josh, no video, hopefully you will take me at my word on this one.

That was also my experience. Not so hard to do if you keep the turn shape medium or smaller. Harder if you do very long and slow turn like JB did in his demo.

How about just the right amount of ski tipping that will generate sufficient turning inputs AND grip to counter the momentum that would continue a straight line?

Isn't that more or less the same as #5? If you do "just the right amount of tipping" with backwards momentum I assume the tips would drift out.

 

[Jamt]

I think we're having a definitional disagreement. Maybe the difference in opinion here is of the term "Carved" vs "brushed".

I won't assert that you can't do the task totally one footed without using your edges.

I will assert that the physics of a one footed "Brushed" turn works just fine, assuming:

A shaped ski that's wider at the tip and narrower at the back with a parabolic sidecut.
"Brushed" means "a wider path through the snow than a single ski edge" aka the track is "brushed" out because the tail went wider than the tip.​

The way the physics works is you:

Pressure the new outside ski by balancing on/over the little toe edge.
Lift the old outside ski.
Tip your leg into the turn and move forward along the length of the ski so that the FRONT of the outside ski engages the snow.

The ski will engage, and start to turn because it is bent, and the sidecut is moving you.​

By varying the amount of edge angle, and how much you bias your weight forward - the ski will vary in performance between a brushed <---> carved (edge locked, one line through the snow)

The bias of the weight forward causes the front of the ski to grip more while the tail grips less and tends to "wash out" or take a slightly larger track. Leaving what I would call a "brushed" track.​

The turning force happens because the difference in pressure between the tip/tail of the ski, and the fact that the wider tip wants to turn more than the narrower tail. That's the solution to the "where's the imbalance in the force?" dilemma. You aren't skiing on a steel 2x4 that can't bend and is completely symmetric, you're skiing on a shaped ski (or at least you are if you want this to work).

Great post, and I agree with most of this, but I think there is a common misunderstanding that the tail brushes or "washes" out in a brushed turn and that the tip is not. It is actually the other way around. Since the ski is bent the tail part is more aligned in the skiing direction than the tip. This picture illustrates nicely.
The "transition" part in this picture is what I would call brushed. It can actually be hard to see on a good brushed turn track that it was not edge locked, which is one of the reasons I don't subscribe to the black or white view on carved vs non-carved.

 

[LiquidFeet]

@Jamt, this looks like a stivot.

I've always wondered how, in a stivot, the skier switches from the skid to the carve, and assumed there was some muscular re-alignment of the skis with their direction of travel involved. This image makes it look like the skier moves the tips downhill/away to make the re-alignment happen. I'm assuming also a pull-back as an aid to making this happen.

It's so cool that someone put this together. It's in English. Were did you find this?

And as for the top half of this "turn" ...
I'm noticing that the skis are turning to point in the new direction (attack angle is changing) ... but the direction of travel is slow to change.
In the second box the ski is beginning to travel downhill, and at this point the skier begins the re-alignment of the tip with the direction of travel.
What's labelled as the transition (a new use of the term) is where the re-alignment happens, and there the attack angle stops increasing. Now the skis travel downhill in the direction they are pointed.
The change in the direction of travel ramps up only when the re-alignment is done in the last part at the bottom of the turn.
So the top of this "turn" doesn't show much actual turning, if any. It's kinda like a sideways hockey-slide.

If the skier did not re-align the tip with the direction of travel, I'm thinking this skidding ski would never point in the new direction because of turn forces alone. Gravity would pull it downhill, though. And the skier would have to turn it manually. Back to the thread's topic... this thread shows such manual turning is difficult to do if not impossible with only one foot on the snow (bar stool example comes to mind).

Thoughts? Comments? Yes, no?

 

[Smear]

My interpretation of of brushing: keeping the ski at a skidding with a relatively constant steering angle.

I don't think it is physically impossible. I don't think it's about torque. Or fulcrum. That might be the explanation why one-footed pivot slips are so hard, but doesn't explain why all types of one-footed skidding is difficult.

I think it's about the difficulty of staying in balance* when your position changes the forces you are balancing against. The same is the case when doing it carved. But a little more or a little less edge on a carving ski doesn't change the forces at play that much, neither does a little fore/aft. So that is a manageable balancing situation.

On brushing ski a little bit more edge or more fore/aft can have a huge effect on how much force you get the snow and where its pointing (slowing you down or turning you). Can be broken down into two components: pure sideways effects and changing steering angle effects. How hard is it to sideslip down on one ski on a smooth surface? Then there is the effect of changing steering angle. Like if the ski slow down more than anticipated, edge angle gets flatter and you get positioned more forward. Ski rotates more, to counteract that you can edge it more, but then forces increase etc... Easily gets out of hand.

When you have another point of contact it is much easier to keep a stable edge angle and position over the ski.

In a wedge it's child's play.

With a very light pole drag it's difficult.

Long slow brushed turns without any other contact than one ski. Agree with @Josh Matta that this hasn't been shown yet.

(*) Agree that skiing is a dynamic balance. When it's get out of hand we turn to the other direction or fall inside ;-)

 

[LiquidFeet]

falling leaf:

Side-slip straight down the fall line with edge angles constant. Maintain straight-down-the-fall-line travel.
Bend forward at the ankle to put more mass over the fronts of the skis, keeping the edge angles constant.
DO NOT allow self to rotate feet or legs, or uncoil your countered body. Both of these will definitely turn the skis.

Without that rotary help, will the skis turn to point downhill?
IME they keep sideslipping straight downhill, but the line shifts over toward the trees.
My conclusion: with no edging change and no rotary input, even on two skis, getting forward on the ski does not alone cause the tips to seek the fall line.

I think (not sure, as I forgot to check and have finished skiing for the season) that edge changes don't make the tips seek the fall line either.

Why I'm pointing this out is that, if I'm correct, rotary input must be necessary for one-ski schmeered turns.
Do others here get the same result? Am I correct?

NO WAIT. I'm forgetting about forward momentum of the CoM, which is present in real turns and absent in side-slips. Of course.
It's forward momentum and tipping changes and weighting the shovel that gets the turn to start. Insufficient platform angle will determine whether it's carved or schmeered/drifted/steered/brushed.

Clearly I'm typing while thinking.

 

[James]

If you pressure the tips, the front of the ski will have more friction and the tails will drop. Maybe. There's so many subtle things we do that it's hard be definitive.
Remember we went through this on epic? The guy who was going to "prove" the tips seek the fall line had a subtle rotation that did so. It takes almost nothing, he didn't know he was doing it. Then there was the guy who refused to believe you could start a turn from a slow traverse I think. Some instructors from Aspen demoed it with Bob.

Plus the infamous two footed release where hh and Diana demo a blocking pole plant like a compass point to make a relatively short turn from a release. There the weight is more to heels that slow the tails, there's an anticipated postion, and the body is pretty far downhill reaching with the pole. Everything is set up to turn around the pivot point - the pole.

 

[Tim Hodgson]

Holy crap! James that was a brilliant post! (Maybe not for everybody here, but for me you have created new thoughts.)

At 0.59 and again at 1.29 is there daylight under JB's left ski (outside) while initiating the turn to the right?


Definitely in the first part of the video (JB in green/blue pants) the tails are doing the brushing -- not the tips. Correct?

Calling: Jonathan Ballou to explain this magic!

 

[Rod9301]

falling leaf:

Side-slip straight down the fall line with edge angles constant. Maintain straight-down-the-fall-line travel.
Bend forward at the ankle to put more mass over the fronts of the skis, keeping the edge angles constant.
DO NOT allow self to rotate feet or legs, or uncoil your countered body. Both of these will definitely turn the skis.

Without that rotary help, will the skis turn to point downhill?
IME they keep sideslipping straight downhill, but the line shifts over toward the trees.
My conclusion: with no edging change and no rotary input, even on two skis, getting forward on the ski does not alone cause the tips to seek the fall line.

I think (not sure, as I forgot to check and have finished skiing for the season) that edge changes don't make the tips seek the fall line either.

Why I'm pointing this out is that, if I'm correct, rotary input must be necessary for one-ski schmeered turns.
Do others here get the same result? Am I correct?

NO WAIT. I'm forgetting about forward momentum of the CoM, which is present in real turns and absent in side-slips. Of course.
It's forward momentum and tipping changes and weighting the shovel that gets the turn to start. Insufficient platform angle will determine whether it's carved or schmeered/drifted/steered/brushed.

Clearly I'm typing while thinking.

Really easy to get from a stop, let skis search the fall line we without any rotary.

Ok, so maybe it will take a couple of hours practice, but I do it often.

 

[Rod9301]

Holy crap! James that was a brilliant post! (Maybe not for everybody here, but for me you have created new thoughts.)

At 0.59 and again at 1.29 is there daylight under JB's left ski (outside) while initiating the turn to the right?


Definitely in the first part of the video (JB in green/blue pants) the tails are doing the brushing -- not the tips. Correct?

Calling: Jonathan Ballou to explain this magic!

We'l yeah, that's psia.

Look at pmts videos of brushed turns, no rotary involved.

 

[Seldomski]

If you had a reverse camber, reverse sidecut ski, it seems like a one-footed brushed turn should be possible by shifting weight fore/aft. This assumes a hardpack groomed surface. I think this would be the easiest equipment + snow surface to achieve the task.

I think some of the argument here may be from particulars in the equipment and/or snow surfaces used for the demos. For instance, I think one-footed brushed turn may be near hopeless to show in knee deep powder...

Maybe this is easier to do on groomed surface if your ski has no camber or edges and surface is dust on hard pack (ie very easy to skid).

...wish I could ski more this season ...

Carry on.

 

[Swede]

Perhaps this thread has diverged, but I like this US Ski Team video of the outside to outside drill. Inside ski should not touch the snow, poles should not be crutches in the turn.

 

[Jamt]

@Jamt, this looks like a stivot.

It's so cool that someone put this together. It's in English. Were did you find this?

If the skier did not re-align the tip with the direction of travel, I'm thinking this skidding ski would never point in the new direction because of turn forces alone. Gravity would pull it downhill, though. And the skier would have to turn it manually. Back to the thread's topic... this thread shows such manual turning is difficult to do if not impossible with only one foot on the snow (bar stool example comes to mind).

Thoughts? Comments? Yes, no?

It is similar to a stivot, but the intent is different. In a GS stivot the intent is to reduce speed and go a straighter line. In SL it is just about making the line, you cannot "carve" it.
You don't really have to do anything to redirect the tips. As more and more of the tail gets in the groove the tail will have more grip and the tips will snap out to carve the groove.

If you pressure the tips, the front of the ski will have more friction and the tails will drop. Maybe. There's so many subtle things we do that it's hard be definitive.
Remember we went through this on epic? The guy who was going to "prove" the tips seek the fall line had a subtle rotation that did so. It takes almost nothing, he didn't know he was doing it. Then there was the guy who refused to believe you could start a turn from a slow traverse I think. Some instructors from Aspen demoed it with Bob.

Plus the infamous two footed release where hh and Diana demo a blocking pole plant like a compass point to make a relatively short turn from a release. There the weight is more to heels that slow the tails, there's an anticipated postion, and the body is pretty far downhill reaching with the pole. Everything is set up to turn around the pivot point - the pole.

If you stand on an ski with infinite torsion resistance and de-edge it without rotary the ski will slip sideways without rotation, it does no matter where you stand.
In reality however the skis torsional properties will affect what happens. If your CoM is in front of the ski center the ski part just behind the CoM will be much stiffer than the ski part just in front of the COM. This will cause the front part to twist more, and thus the front will slide down more.

This does not consider dynamics, which is the other way to affect the ski. Imagine for instance that you have a totally unweighted transition with the skis in the air. If you land with a significant attack angle with the tips first that force will make the ski rotate "tails out"

By combining these two concepts you can make the ski turn. When I do the outside to outside in medium or small turns, I suppose it is the seconds concept I use the most, and that is why it is not so hard.
However, if you do really slow long turns with a traverse in between you have to rely more on the first concept, which makes it much more difficult, in particular from a balance point of view.

Perhaps this thread has diverged, but I like this US Ski Team video of the outside to outside drill. Inside ski should not touch the snow, poles should not be crutches in the turn.

Nicely executed, but in the context of this discussion I think they are too carved.

 

[Jamt]

We'l yeah, that's psia.

Look at pmts videos of brushed turns, no rotary involved.

As far as I understand a PMTS brush is quite powered by pulling the inside foot back and tipping it more than the outside.
That has little to do with outside to outside brushed turns, but If you have a pmts video of one-legged brushed turns that would be great input to this discussion.

 

[François Pugh]

I'm sure @Jamt can do this in his head. Draw a free-body diagram; include all the forces acting on the skier/skis.
a) Top of turn skis pointing across fall line at the trees on the side of the run, release edges completely. The tips will seek the fall line as surely as a becalmed sailboat's keel seeks the bottom.
b) After fall line, engage edges (draw a new free-body diagram to include the new force) complete the turn. Angular momentum would make the skis go past the fall line on its own, but we want more turn than that.
c) repeat.

 

[James]

It is similar to a stivot, but the intent is different. In a GS stivot the intent is to reduce speed and go a straighter line. In SL it is just about making the line, you cannot "carve" it.
You don't really have to do anything to redirect the tips. As more and more of the tail gets in the groove the tail will have more grip and the tips will snap out to carve the groove.



If you stand on an ski with infinite torsion resistance and de-edge it without rotary the ski will slip sideways without rotation, it does no matter where you stand.
In reality however the skis torsional properties will affect what happens. If your CoM is in front of the ski center the ski part just behind the CoM will be much stiffer than the ski part just in front of the COM. This will cause the front part to twist more, and thus the front will slide down more.

This does not consider dynamics, which is the other way to affect the ski. Imagine for instance that you have a totally unweighted transition with the skis in the air. If you land with a significant attack angle with the tips first that force will make the ski rotate "tails out"

By combining these two concepts you can make the ski turn. When I do the outside to outside in medium or small turns, I suppose it is the seconds concept I use the most, and that is why it is not so hard.

So I played with some side slipping yesterday. With 2 different skis, a slalom and an 180/87mm 19.5 m fat carver.
Results:
weighting tails- like very excessively sitting back.
The tails of the skis went down and backwards. At some point they go back far enough and the tips head down. Sort of an automatic falling leaf.

Weighting front:
This was interesting. There's a very fine line where things shiftt. I'm not sure I could say without video what exactly makea the difference.
But, leaning toward tips, weighting front of boot, -the tails go down. This could happen whether in a ski jump like position or looking down slope. Tails drop a bit, you go backwards, then auto correct and tips go down. On the slalom ski it seemed to go backwards more than the other ski. (pretty sure, may be mis remembering).

However, it was incredibly easy to shift the tail dropping/backward movement to a tips dropping downhill. A very slight opening of even the shoulder, but really the hips, and the tips went right down. By opening I mean if the left side is downhill you're moving the left hip or shoulder back.
It was a very slight move. There may be other things going on that are unconscious. People who have a dofficult time with thw tipa seekinf the fall line are probably. Oth leaning uphill- very common with simple sideslip, and blocking with the downhill hip.

For all of these, I had an uphill tip lead to start. As you'd stand naturally across a slope. Snow was not real smooth but hard base with some loose granular on top. I had to sidestep a little down to clear the small pile of snow that would build up from a soft hockey stop. Most of the pitches I used were pretty gentle but sliding happened easily.