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Teaching Angulation - Page 4

post #91 of 128
Rick, for the record you aren't one of the people I'm complaining about. :-)

I think the balance argument is valid and definitely angulation is one of the things you use to control balance..but I also think you're overlooking the increased edging that results from changing the ratio between the centrifigal force vector and the Gravity vector (discussed earlier), while still maintaining skiing balance.

As you move your CM out away from the inside of the turn via Angulation and counter, you essentially change the angle of the Green arrow so that it points more down into the earth... This increases the holding power of your edges. LeMaster discusses this very concept at length. Angulation is also what directs the forces more accurately to your edge instead of a point in the base of the ski directly under your foot halfway between the two edges (again, discussed at length by LeMaster). Angulation(and counter) do the same thing for skiing that riding with your weight over the front wheel in a turn does for mountain biking.

I think also that if someone isn't angulating much...they are probably riding on the inside ski "too much" as well..which is a whole nother topic. I put "too much" in quotes because opinions will vary and I don't want to fuel enother debate about that right now. Most likely they are standing on the inside ski to keep from falling over(since they aren't balanced as you pointed out Rick), but also, they're using their inside ski to edge and make up for the fact that their outside ski isn't edging as well as it could be. If they stood on it and angulated over it..their outside ski would hold very well. There are many advantages to skiing with most/all of the force and carving being handled by the outside ski. There are also situations that come up where its handy to be able to ski almost completely on the inside ski. With modern technology more and more racers do pull that out of their bag of tricks, but its not what i would consider their main meat and potatoes turn.. most of the time they are working towards standing on their outside ski and maximizing its edge power.
post #92 of 128
Quote:
Originally Posted by dewdman42
I think the balance argument is valid and definitely angulation is one of the things you use to control balance..but I also think you're overlooking the increased edging that results from changing the ratio between the centrifigal force vector and the Gravity vector (discussed earlier), while still maintaining skiing balance.

As you move your CM out away from the inside of the turn via Angulation and counter, you essentially change the angle of the Green arrow so that it points more down into the earth...
dewd, think that over a little more.

You've said earlier in this thread, and you were totally right, that the angle of the resultant force vector (green arrow) is determined by the relationship between current values of gravity to centrifugal force. If that relationship remains intact (if the values of each don't change), so too does the angle of the green arrow (resultant vector) remain unchanged. As long as speed and edge angle (turn shape) remain the same, moving the CM laterally via angulation does not change the angle of the resultant force vector (green arrow), it only changes where that arrow hits the ground (the balance point).

Given constant speed and turn shape, adding angulation will always move the point of balance outside, and reducing angulation will always move the point of balance inside.



Quote:
Angulation is also what directs the forces more accurately to your edge instead of a point in the base of the ski directly under your foot halfway between the two edges (again, discussed at length by LeMaster).
Guess I need to read that book, dewd. If I were to award credit for directing pressure to the engaged edge of the skis, I would give it to the power of counter and neutral/fore pressure to promote pronation in the outside foot, and supination in the inside foot. Are you familiar with that concept? It's quite interesting,,, and it works. Not too many are out there have a clear understanding of this.



Quote:
I think also that if someone isn't angulating much...they are probably riding on the inside ski "too much" as well..which is a whole nother topic.
Yes it is another topic. Spinner has it going right now in a new thread. I'll save specific comments for there, but I will say that if someone is riding the inside ski more than desired, or to the point of causing the outside ski to lose pressure and track away, then you're absolutely right, a lack of an adequate amount of angulation is definitely the problem.
post #93 of 128
If your angulating you're skiing too slow .
post #94 of 128
Quote:
Originally Posted by Ghost
If your angulating you're skiing too slow .
Now there's a man after my own heart!!

The dream turns: 223 cm skis, 45+ meter sidecut, no need for angulation.
post #95 of 128
Quote:
Originally Posted by Rick
You've said earlier in this thread, and you were totally right, that the angle of the resultant force vector (green arrow) is determined by the relationship between current values of gravity to centrifugal force. If that relationship remains intact (if the values of each don't change), so too does the angle of the green arrow (resultant vector) remain unchanged. As long as speed and edge angle (turn shape) remain the same, moving the CM laterally via angulation does not change the angle of the resultant force vector (green arrow), it only changes where that arrow hits the ground (the balance point).
Yea I see your point...... which I even said more or less the same thing earlier.....I should try listening to myself sometime......the Green arrow is not effected by body positioning..

Quote:

Given constant speed and turn shape, adding angulation will always move the point of balance outside, and reducing angulation will always move the point of balance inside.
yes

Quote:
Guess I need to read that book, dewd.
Yes you absolutely should. I think its about $10 on Amazon and you can read it in 2-3 hours at the most. Everyone serious about skiing or teaching should read this book in my opinon. I need to read it again actually.

Quote:
If I were to award credit for directing pressure to the engaged edge of the skis, I would give it to the power of counter and neutral/fore pressure to promote pronation in the outside foot, and supination in the inside foot. Are you familiar with that concept? It's quite interesting,,, and it works. Not to many are out there have a clear understanding of this.
I see what you're getting at with Foot tipping. I think that's another discussion as well.

ok, I just pulled out LeMaster's book to see if I had anything wrong. I need to read it again.

Not sure if its ok to quote stuff from his book here or not so I won't...

If you get the book, see pp 18-20, 103-116

I think you've convinced me that the green arrow does not change..and hence angulation is more about balance point. I re-read some LeMaster to get a better handle on what he was saying. He does talk about the two vectors and how to take advantage of the gravity vector better, but its not at all about changing the angle of it..as you pointed out.thanks for that correction.. The Green vector is really not changeable.Its how we position our body to take advantage of those two forces(one resultant force) that will maximize the effects of the gravity vector.

Essentially, he points out a few things about edge grip:

1 - On soft snow everything is easier, so less precision is required

2 - On hard snow, there are two keys to getting maximum grip

a - Apply all the force available to as small an area as possible, maximizing pressure on the snow. (that's why sharper edges work better than dull ones..it has to do with minimizing the surface area touching the snow to maximize the force per square nanometer).

b - Apply all the force to one ski. On this point he goes into great detail about penetrating forces(gravity) and side slipping forces(centrifigal). he talks about how when you're riding on both skis, the inside ski gets way more penetrating force than it needs and the outside ski gets not enough due to the way our bodies are biomechanically organized. Therefore getting weight to the outside ski is crucial in order to maximize the penetrating force there verus the side-slipping force. (his explanation is better than mine).

3 - He talks about something called the "Critical edge angle". This angle is between the base of the ski and the green arrow we have been talking about. This angle must be 90 degrees or more. It does not need to be more, but if it is less, the ski will slip sideways. Only 90 degrees from the Green arrow is required.

4 - In order to get the skis angled over to the critical edge angle AND maintain balance..some angulation will be required. But more importantly...

5 - As he explains it, the tricky part is not getting the skis on edge, but rather HOLDING them on edge for the duration of the turn and not letting yor ankles roll over such that the critical edge angle is reduced below 90. This has to do with what I was talking about earlier with regards to the fact that the edge of the ski is not lined up directly under the middle of our foot. Therefore, there is a levering effect as the forces are transmitted down our leg onto the lever created by our ski edge on the snow. He draws a contrast to ice skaters who easily hold an edge on 8 inch blades, holding tight arcs on absolute sheet ice. One of the key differences is that their edges are directly below their feet, not several cm's to the side. So the downward forces are transmitted directly the edge..maxmizing the penetrating force into the ice again.

Angulation acomplishes something that lines up the legs in such a way that the green arrow forces are directed in a line directly to the side of the foot instead of to the middle of the foot. This causes the pressure to go directly down to the edge instead of creating a lever which may lever-down and lose the critical edge angle.

(note that in softer snow, the ski sinks down into the snow far enough that the forces going to the middle of the foot(without angulation) will still be pushing against snow and the ski won't lever down so easily..it will maintain the edge angle..this is one reason why softer snow is easier for many.)

(he also explains that lifters are another way to actually bring the edge of the ski more in line with the green arrow force vector coming down the leg with less angulation, contrary to everyone else saying it just allows you to get greater edge angles without booting out. In fact lifters are designed to reduce this lever effect. By that notion, fatter skis need taller lifters interestingly enough.)

Summary

So angulation is used to increase the edge angle(while maintaining balance and not being too overly banked, as well as it directs the green arrow forces directly to the edge so that the lever effect won't happen.

6 - Counter is primarily designed to make angulation easier. It positions the body in such a way that the larger powerful muscles can be used to angulate properly.

I will quote only one bit about ICE(p 107): "Most important, though, is to put all your weight on your outside ski and angulate enough at the knee and hip. Remember that most skiers do not angulate enough at the hip, so put your hips into the turn and reach out over your downhill ski with your arms and torso. Do not be afraid to come down hard on your ski when you need it to hold. If you don't push it into the snow, your ski won't hold. Focus on your downhill ski, and if you feel the tail slip, you are too far forward. If you feel the outside ski run away from you down the hill, you are too far back."

Everything I have said about angulating and getting your weight over the outside ski is coming from this perspective. To me its like getting my weight over the front wheel when I corner on a mountain bike. Same basic concept, maximizing the penetrating force compared to side slipping force. Skiing is a bit more complicated...especially when we start analyzing all the physics, but in the end, the mental model of just trying to get out over the top of the outside ski as much as possible while maintaining balance is really the key to the whole thing.
post #96 of 128
OK, I'm pretty much on board with that dewd. I could add tweaks here and there, but I'm weary.
post #97 of 128
yep dewdman...

that was one thing the ex-wc guy in livigno rubbed into me re my shoulder position over outside ski... if I want to ski how I desire then I NEED to learn to get that shoulder just that tad forward over that ski... because the SMALL positional change seems to make BIG difference in ski performance stuff...
post #98 of 128
Quote:
Not sure if its ok to quote stuff from his book here or not so I won't...

Dewdman,

Copyright fair use is ok (short quotes with added commentary by the poster). Pure quotes are a violation. Links are preferred.
post #99 of 128
Thread Starter 
I'm learning something!! Get work all. Good discussion with a congenial attitude.
post #100 of 128
Dewdman42,
Excellent Post
post #101 of 128
Quote:
Originally Posted by dewdman42
Without angulation your Center of Mass (CM) is way on the inside of the turn and all of your momentum is pushing outwards on the edges, while very little force is pushing the edges directly down into the snow. The reason for angulation is to get your CM out over your skis in order to increase the downward force (from gravity) into the snow.
I've read this paragraph over and over....and unless I'm wrong you are saying that the result of/or reason for angulation is to move the CM over the skis. Have I got that right ?
post #102 of 128
Read all of my posts..there was much debate and arguing and I don't want to explain it again. I explained it about as well as possible without photocopying pages from Lemaster's book here. Get his book for $10 and read it.. Well worth it.
post #103 of 128
Quote:
Originally Posted by dewdman42
3 - He talks about something called the "Critical edge angle". This angle is between the base of the ski and the green arrow we have been talking about. This angle must be 90 degrees or more. It does not need to be more, but if it is less, the ski will slip sideways. Only 90 degrees from the Green arrow is required.
I've been thinking this over, and it makes perfect sense. If the net force you apply to the ski is at a greater than 90 degree angle to the plane of the ski, ie. has a component directed parallel to the base toward the outside or up edge, then you will dislodge the ski.

Could it be that I have not been leaning as far over as I had thought? I mean, it's not like a motorcycle where you can look at the wear on your exhaust and foot pegs to determine your lean angle.

I've been trying to match the theory to my experience (lots of high-speed flirting with the limits of traction on smooth surfaces with my 208 SG skis) since you posted this.

So far I've come up with: Either I'm just mistaken, and haven't been over-banking, or ....
The only way to get cm further inside the curve without more down force than centrifugal force and gravity provides at the critical angle is to selectively increase the down force first on the front and then on the back, while staying balanced. I seem to remember playing at this a long time ago as a result of a ski lesson, doing very long radius turns on smooth hardpack and trying to turn ever faster without letting the edge slip out. I didn't realize it at the time, but I now think rotary movements were used to pressure the edge. The extra downforce necessarily causes an upward acceleration, and can only be brief. This blends in well with bending the old straight skis via shifting force from tip to tail as the turn progresses. I haven't explored it enough on the new skis.

Skiing is easier than thinking about it.:
post #104 of 128
Hey Ghost..I'm just feeling a little bit honored that you were out skiing and thinking about what I wrote...regardless of whether you agree yet...Its awesome to see someone take what you write or say seriously.. So THANKS FOR THAT.

There are a lot of things we get wrong when we try to analyze our own skiing. We don't really know what the green arrow vector is. We know what we THINK it is. Getting the critical edge angle right is something that comes from years of experience of just knowing how much edge works and how much doesn't for whatever forces are in play. Its about feel, at least for me.

A skier that is just cruising down the mountain with low G-forces doesn't need much edge angle to get clean arcs. Someone who turns a tighter arc, fast, will generate a lot more sideways G-forces and thus the Green Arrow will point more out instead of down, the centrifigal will add up more in that direction..thus their critical edge angle will need to be higher. Pretty much, you have been doing this by feel the whole time... as have been most of us. The physics are only to explain..I doubt many people think about physics when skiing most of the time.

Also, I think you can have a higher edge angle then you really need and that does not neccessarily hurt you. it doesn't really help you either in terms of edge grip, but it is certainly not going to make your edges slip. In fact an argument can be made that going for a higher-then-needed edge angle will just put you into a comfort zone of room for error to avoid slippage due to falling back below the critical edge angle.

There is some more argument which can be made that if your edge angle is higher than the critical edge angle..perhaps you are bending the ski into a tighter radius then you would otherwise...which will result in more sideways G forces which will result in the need for higher edge angle, etc..

I've also heard some of the race coaches on here comment that super high edge angles are not always needed but sometimes we do them strictly for style sake. There is also the fact of getting the CM inside, angulating, etc..and so having the higher than neccessary edge angles may come into play for maintaining a certain kind of angulated balance point.
post #105 of 128
Quote:
Originally Posted by Ghost
The only way to get cm further inside the curve without more down force than centrifugal force and gravity provides at the critical angle is to selectively increase the down force first on the front and then on the back, while staying balanced. I seem to remember playing at this a long time ago as a result of a ski lesson, doing very long radius turns on smooth hardpack and trying to turn ever faster without letting the edge slip out. I didn't realize it at the time, but I now think rotary movements were used to pressure the edge. The extra downforce necessarily causes an upward acceleration, and can only be brief. This blends in well with bending the old straight skis via shifting force from tip to tail as the turn progresses. I haven't explored it enough on the new skis.
ps - I'm not a big fan of talking about rotary-driven leg forces applied to the skis, especially when we're talking about race-style groomer performance. Some others will disagree with me I'm sure. PSIA leans that way.

I personally also don't think too much of the whole front to back weight transfer that some people have talked about. Perhaps at elite levels of racing which I don't know anything about so I'll leave it some other expert to explain if that is what they are doing. For most people I think you can simply avoid falling back too far and stay centered. You do have to make an assertive movement forward at the turn transition or else you will fall back. But I don't really think you have to aggressively push on the shovel of the ski or finish the turn out riding on the tail.. Not with today's skis.

This last paragraph, I wasn't completely clear on what you were meaning to say you're trying to accomplish. I think the key to getting the downward force maximized on your outside ski is to angulate angulate angulate...
post #106 of 128
Quote:
Originally Posted by dewdman42
Hey Ghost..I'm just feeling a little bit honored that you were out skiing and thinking about what I wrote...regardless of whether you agree yet...Its awesome to see someone take what you write or say seriously.. So THANKS FOR THAT.
Give yourself a big pat on the back; you deserve it. I really think you've got angulation\inclination nailed down.

I skied basically by feel and didn't think too much about technique until I stumbled over this forum about a year and a half ago. I am over-educated, so do get most of the physics though. I get the whole angle of the ski to the slope affects turn radius, and get the F=ma. What I find intriguing, and a constant goal of mine, is trying to get more g force in a given radius turn (allowing you to go faster around the corner so to speak), than you would be in balance with your cm in a pure banked turn. I.E is reverse angulation possible? If so I want to know how to do it. On the other hand, I also want to travel faster than the speed of light.

Unfortunately, most of my reliable data comes from experience with old straight skis (70m radius). It just goes by too fast with the 13m radius skis for me to yet have a handle on exactly where I am on the new skis at their limit of traction. I need to experiment some more.
post #107 of 128
I totally believe its possible for you to go faster than the speed of light.. :-)

But regarding your desire to increase G-forces for a given turn shape to go faster around a turn. Hmm.. I think you're wanting something for nothing. You are trying to get some kind of extra acceleration that you're hoping to goose out of the G-forces or cosmos. There are other threads related to accelerating out of a turn. I'm not really sure its possible myself. I've largely been ignoring those threads. Go see what they have to say about it. For me I just try to retain as much of the G-forces as I can and not lose them to skidding. To me, this translates into a FEELING of acceleration as I change direction. Whether this actually is or not I will leave for others to decide.

Gravity is constant. Centrifigal force is based on your turn shape. There is also momentum, which we haven't really considered much, but that is a factor as well. As you ski down a hill, gravity is converted into momentum. Gravity is the only energy input you get. Skiing fast is all about maximizing the efficiency that gravity is converted into forward momentum.

Take a case where you are just schussing straight down a hill. What energy you have available to you for speed is gravity and whatever momentum you have already converted from gravity(and friction is slowing you down). The longer you run straight, the more gravity is converted into momentum and friction scrubs some away. Eventually, you hit a point where the momentum conversion can't keep up with the friction and that is your max tucking speed.

When you make a turn, momentum is converted to some degree into centrifigal force. The tighter you turn, the more of your momentum is converted into centrifigal force. Centrifigal force doesn't just come out of thin air. It comes from whatever momentum you had going into the turn.

At any given instant the goal will be to use your body in such a way that those G-forces are not squandered sideways in skidding or side slipping directions and rather are transmitted to the skis moving forward only on their rails. If you skid, then that is like taking the momentum you have built up, converting it to centrifigal force and then giving it away by slipping sideways.

That's why you should angulate/counter, etc to maximize traction, which will maximize how well your skis will grip and slide forward instead of sideways. it will reduce how much of your saved up momentum that will be squandered away. Moving your CM more inside will not harness any G forces from the cosmos to accelerate you. There are many tactics for how to move your CM relative to the path of your skis, but all of these things are related to the line you need to make your skis go on...say to make it around gates in the shortest line possible with the least amount of sideways skidding.....

There really isn't any other way you're going to somehow capture hidden energy from the cosmos to make you go any faster than that.

cheers....
post #108 of 128
I understand where the energy is comming from. I'm not trying to go faster out of the corner than into it here. Here's what I'm shooting for. There is a turn at the bottom of a short chute. You have to make the turn or become one with the trees, rockface, lift-tower or what have you. The turn you are required to go around dictates say at most 35 m turn radius. The acceleration you experience going around that turn is a=v^2/r. If you can pull 1 g in the turn you are able to go about 19m/s. You have to make a few turns down the chute to make sure your not going more than 19m/s around that turn and then lean your skis over to about 45 degrees. A mere 19m/s is a waste of a good chute! Now if you can pull 4 gs, you can go 36 m/s around that same corner (much more exciting), so go ahead and shush that little chute. In good solid snow it's no problem; just tip the skis more. However on ice with some shape to your ski, tipping the skis more is not an option, as they would then TRY to carve a smaller turn on account of the sidecut. Just banking would have you going over the top; you body has to lean in more to account for the added momentum and resulting greater centrifugal forces, but you can't tip the skis more because they would dial in a different turn radius.

Current practice at pushing my new SCs past their limits has me tipping the skis more, them dialing in a smaller radius and the skis tracking well directly underfoot, but slipping at tip and tail.
post #109 of 128
you really do want to go the speed of light...

If you are doing a pure carve turn on ice out of a narrow 45 degree chute with risk of hitting something or going off a cliff should you not make the turn, then you're a lot gutsier than I ever plan to be. Personally, I think letting the edges drift a little bit is the appropriate thing to do..that let's go of some of the G forces, it slows you down a bit and allows you to make a tighter turn then PERHAPS your skis would be able to do otherwise. At some point there are limits to what your skis can do. I didn't realize you were talking about that kind of terrain. You may not have to drift the skiis all that much, nor scrub that much speed...in fact I personally think if you aren't careful the skis will break free and skid away out of control...so its a subtle move.

In any case, everything is still the same...you still want to remain angulated in order to obtain maximum edge grip power (and countered). Of course, as you pointed out.the tighter you turn, the more inclinated you need to be to stay balanced against the G forces...and that is probably exactly the kind of situation where you might have to have your skis edged higher than the critical edge angle so that you will be able to angulate. MAYBE.

Personally I think it works out about right the way skis are designed in terms of the inclination matching the critical edge angle and getting about the right turn radius. However, if you are doing a move like that on slalom skis, then make sure to leave me in your will. You'd be much much much better off with a longer, 20m sidecut big mountain ski... that way you can bend the crap out of the ski in a high G turn and its not going to oversteer on you.

In fact, the higher G your turn is, the more crucial it is that you are angulated. Watch the downhill WC guys..the tightest, fastest turns are the ones where they are most focused on getting countered and angulated.
post #110 of 128
Not to worry Dewdman, the slalom skis are new to me. I only push them where I have lots of runout room, so if i misjudge, it's no biggee; I can recover and scarve a wider turn. I have done some pretty crazy things with those old SGs though (only after getting to know them pretty well). What can I say? "Hi. My name is Ghost, and I'm a recovering adrenaline junkie."
post #111 of 128
:-)
post #112 of 128
Quote:
Originally Posted by dewdman42
Why then angulate? And why won't the edges just hold without angulation? Without angulation your Center of Mass (CM) is way on the inside of the turn and all of your momentum is pushing outwards on the edges, while very little force is pushing the edges directly down into the snow. The reason for angulation is to get your CM out over your skis in order to increase the downward force (from gravity) into the snow. Ideally, when this force is great enough, the edge bites into the snow better and will prevent the sideways centrifigal forces from allowing the ski to slip sideways.

There's more.. Without angulation, the forces from your CM traveling down your leg to your skis want to be transmitted to the center of the base of the ski, not the edge...if you were just banked that is. When you angulate, you also change the vector of force transmitting down your leg so that it lines up closer to the actual edge of the ski and not the middle of the base. Believe it or not, this is actually the main purpose of lifters on bindings...to position the ski in line with that force vector so that the forces are transmitted directly to the edge instead of the center of the base or at least inwards from the actual edge.

(ask yourself why an ice skater can carve a seriously tight turn on an 8 inch edge going quite fast on sheer ice? Partly the edge is directly under their foot, which helps to transmit the forces down the leg directly to the edge without having to do any funky body positioning as I just describe, and partly its because the edge is only 8 inches so there is more force per inch pushing that edge down into the ice to give traction).

The key here is to maximize the downward force onto your ski edge, enough to create enough traction to exceed the sideways centrigal forces.

If you only bank the turns it creates a lot of centrifigal force...and practically no downward force...so even if the skis are way up on edge..they are not going to track nearly as well as if you are angulated, which gets your CM out over the skis more...such that your CM is pushing down via gravity into the snow....in addition to the centrifigal forces that are trying to slide sideways.

This is why you need to angulate. At recreational level of skiing, big edge angles are not required AT ALL to carve clean arcs. However, angulation is absolutely required and the more pressure you can put on the outside ski while you do it..the better it will track...(just like an 8 inch ice skate edge). If you try to spread the weight onto your inside ski...your edges will in fact become less effective, not more.

If you don't believe me...go read Ron LeMaster...this is all almost verbatim from his book...
dewdman42,

I don't want to start a war. I don't belive that the above post represents what Lemaster is saying. In both cases of knee and hip angulation, lemaster says that the CM does NOT move laterally.

Angulation does not produce a downwards force at the ski. If that is lemaster, I'd appreciate a reference, because I cannot find that statement.

What may be the problem is the sidebar about ice. I read the intent there as ensuring that one ski bears all the weigh -- so that there is maximum penetrating force on the edge. The angulation is present to ensure that the levels of torque at the ankle are small to allow the ski to hold. It won't "roll out" of the groove.....
post #113 of 128

Strictly speaking

Strictly speaking, Gravity always acts straight down, and is always equal the the skiers mass times g. Strictly speaking, the vector sum of the forces acting on the skier (gravity + up force of snow + horizontal centripetal force of snow using a frame of reference fixed on the hillside) will cause an acceleration equal to the sum of the forces divided by the mass, or equivalently the rate of change of momentum of the skier.

Most people can more readily see it in the frame of reference fixed on the skier. Still strictly speaking, here the force of gravity acts straight down through the skiers CM, a centrifugal force (equal and in opposite direction to the horizontal force of the snow on the ski so that no acceleration is experienced in the moving frame of reference fixed on the skier) is directed horizontally towards the outside of the turn. To be in balance, the vector sum of the centrifugal force and the gravity force must point through the ski's edge, so that it exactly balances the force of the snow acting on the skis edge(edit: this force applied at the edge will point through the CM) without rotating the skier (skier falls into turn or falls to outside of turn).

The turn diameter on hard snow is set by the inclination or tipping of the ski. At any given speed for this turn radius, there will exist a given amount of centrifugal/centripetal force (depending on frame of reference). Angulation is used to adjust the position of the CM to get the net force to balance against the ski(s)'s edge(s), without changing the inclination (tipping angle of the ski). At slower speeds you have to move the CM closer to the ski or outside of the turn, but must maintain the inclination (keep the skis tipped) in order to keep the small turn radius. At faster speeds you angulate less, as the CM needs to be further inside the turn.

The tricky part is that as you angulate less and less at higher and higher speeds, you reach a point (CM closer to the snow or inside than a line perpendicular to the ski surface) where the CM has to be moved so far away from the skis inside the turn, that the net force acting on the ski actually has a component directed parallel to the skis surface that is now lifting the ski out of its groove. Centrifugal force has become so great compared to gravity that the summ of the forces is now partially lifting your ski out of it's groove. Your only recorse is to tip the skis more, but then your sidecut tries to turn tighter. Sad but true, there is a limit to how far you can push it living on the edge.
post #114 of 128
Lemaster says that the CM does not move laterally. Angulation does not adjust the position of the CM, it adjusts the alignment of the ankle so that it is closer to the line of force to resist the torque at the ankle.

Lemaster also states that angulation is used to fine tune the edge angle without altering the position of the CM.

"As the ski is loaded at the beginning of the control phase, the hip will go toward the inside as the skier folds over at the waist toward the outside of the turn establishing hip angulation. The next order of business in the control phase is to turn the knee inward to fine-tune the critical edge angle and ankle alignement until the edge is felt to be slicing the snow cleanly."

I am quoting Lemaster here, because it appears he has been misunderstood.

"Hip angulation is a movement that brings the head of the outside femur closer to the inside of the turn without moving the center of gravity laterally.

Like knee angulation, hip angulation brings the ankle closer to the line of action of the snoew's reaction force on the ski."

All quotes Ron Lemaster, "The skier's edge", 1999.

The reason that angulation works is that the torque on the ankle is reduced, so that the critical edge angle can be maintained, and the ski does not jump out of the groove. It does NOTHING about the relative location of the CM. The equilibirium requirements are defined solely by the mass and velocity adn turn radius. Angulation cannot reposition the CM otherwise the skier would fall either down or over.
post #115 of 128
Big E,
I think we are in agreement at least on the basics of angulation and inclination, but just looking at it from a different frame of reference. A given turn radius requires a given angle of the skis, regardless of speed. The location of the CM at that turn radius must change depending on the speed. Changing angulation allows the tipping angle of the ski, and the angle of the CM to vary thus permitting skiing at different speeds at the same radius. Whether you call it adjusting ski tipping angle to fit the angulation or adjusting the angulation to fit the ski tipping angle isn't really germane; it's done simultaneously.
post #116 of 128
Yes, the height of the CM above the snow must change.

Increasing angulation will increase the edge angle of the ski. Which in turn, will make the turn tighter, and require that the CM is moved lower to the snow to compensate.

But the movement of the CM downward would be required even if the skier was using inclination to tighten this turn. (That's why the movement of the CM is independent in the definition of angulation.) So if there is such independence, then why angulate at all? To reduce the torque on the ankle, and to maintain pressure on the outside ski....
post #117 of 128
In the most holistic sense, if one simply maintains balance against an edged ski with a flexed ankle, they will angulate.....?

Inclination works to balance against the turning forces (much like a cyclist) while angulation helps us stay balanced while LINKING turns. Think about it.... if we only inclininate (banking) it is difficult to link turns smoothly. If we were to only angulate without inclination we would not be able to ski with any speed. Blending the two makes for good linked turns. Inclination occurs more at the top of the turn while angulation occurs more after the fall line.

So to answer your question.....yes and no.
One could become an excellent skier without "being taught" angulation though one who is having difficulty separating inclination from good angulation would benefit from angulation exercises and understanding it's benefits to good skiing.

In my defense, I only read the initial post so my comments may not be current.
post #118 of 128
Quote:
Originally Posted by Powdigger

So I guess my long winded question is do we teach angulation and if so can someone point me in the right direction with exercises?

or

Is angulation the result of proper skiing and is not separately taught?

ed
Interesting question and thread mostly due to the fact I was just reading Lito Tejada-Flores book "Breakthrough on the New Skis" over the weekend. FWIW he specifically states that he doesn't really mention or teach angulation because it happens naturally if a person is doing everything else correctly. He mentions that other people think it's important to teach it, but he disagrees.

There's differences of opinion in every endeavor.
post #119 of 128
IMO, angulation is not a gimme.
post #120 of 128
Quote:
Originally Posted by BigE
Lemaster says that the CM does not move laterally. Angulation does not adjust the position of the CM, it adjusts the alignment of the ankle so that it is closer to the line of force to resist the torque at the ankle.
Another way of saying this is the line of action of the combined force (gravity and centripetal) goes through the edge.

Quote:
Originally Posted by BigE
Lemaster also states that angulation is used to fine tune the edge angle without altering the position of the CM.




The reason that angulation works is that the torque on the ankle is reduced, so that the critical edge angle can be maintained, and the ski does not jump out of the groove. It does NOTHING about the relative location of the CM. The equilibirium requirements are defined solely by the mass and velocity adn turn radius. Angulation cannot reposition the CM otherwise the skier would fall either down or over.
If you do the turn without angulating (banking) your CM is farther inside and lower down, it's position being dictated by the tipping angle of the ski. This turn will only work (forces balanced) at one speed for any given turn radius. If you want to make that turn more slowly, for example very very slowly, you will need to move your CM closer to the outside of the turn relative to where it is at high speed. Doing the turn with angulation allows you "to fine tune the edge angle without altering the position of the CM" from where it is when not turning or conversly to "adjust it away from the extreme position it would take with no angulation".

Long and short of it is the degree of angulation used depends on the speed for a given turn, or the turn radius at a given speed and allows the skis tipping angle and the position of the CM to vary for any given tipping angle of the ski.
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