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# So, how do YOU get forward? - Page 9

Let's not forget that the ski will be decambered simply due to the skiers weight pushing down near the middle of the ski and the snow pushing up all along the ski. Think 3-dimensionally; a decambered ski in the vertical direction then put on edge is a curved shape in the horizontal direction. In the old days this shape could be augmented by some dynamic vertical loading of the skis while shifting ones centre of pressure forward, just prio to engaging the turn. With sufficient speed, the momentum would take care of bending forces required for the rest of the turn.
Edge set and rebound? remeber those!
Quote:
 Originally Posted by Ghost Let's not forget that the ski will be decambered simply due to the skiers weight pushing down near the middle of the ski and the snow pushing up all along the ski. Think 3-dimensionally; a decambered ski in the vertical direction then put on edge is a curved shape in the horizontal direction. In the old days this shape could be augmented by some dynamic vertical loading of the skis while shifting ones centre of pressure forward, just prio to engaging the turn. With sufficient speed, the momentum would take care of bending forces required for the rest of the turn.
Yes, but this amounts to engaging the whole ski, whether bent or not, not selective engagement of some part of the ski.
Quote:
 Originally Posted by Atomicman Edge set and rebound? remeber those!
Care to elaborate? (yes I do remember but I would like to hear a more detailed description of what was happening, if possible.)
Quote:
 Originally Posted by oisin This is great stuff. Thanks for clarifying the issue. Your articulate description raises another question in my mind which perhaps you might be willing to address. "Turn engagement" is an interesting topic to me and may be central to the whole thread. Your mention of that old saw "tip engagement" takes me back to the old days of "straight skis", especially the very stiff skis from an earlier era. Pleaee allow me to blather a bit: Those skis had very little sidecut and turn shape in a carving type turn was highly dependent on the shape given the ski by bending it. Applying this bending required significant force application. Such forces, it seems to me, were only available relatively late in the turn thus the turning action achieved by this bending of the ski could only be significant when the forces of momentum and gravity could fall against the ski at such an angle as to effect bending (phycisists in our midst please feel free to correct my description of the forces involved). I would imagine that bending the whole ski most efficiently probably involved something approaching perpendicular angles. These angles, I am guessing, could only be achieved after the skis passed the fall line. Prior to that moment, however, some of these forces could be brought to bear diagonally against the ski to bend the forebody (this part is speculation). However, these skis did have some shape in that the forebody close to the tip was wider than the waist and the tail. The angle this formed with respect to the following parts of the ski represented a departure from the direction the ski was travelling. If pressure could be centered on this portion of the ski's edges it might be induced to change direction to follow that angle. This change of direction might presumably be enhanced by any shape given the front of the ski by bending induced by the previously mentioned diagonal application of forces. This, at any rate, is my crude understanding of the significance of "tip engagement" as it apllied, and may still apply, to "turn engagement". I would gues that, in the old days, edge angles early in the turn were not great, relatively speaking, and that, while the forebody of the ski was gripping, the rest of the ski was not and was skidding if only slightly. This is what enabled this tip engagement, so called to be effective in initiating the turn. Now to my question ("I thought you would never ask, he sighed.") Is this an effective or even useful technique in the modern race turn? Edge angles in such turns are relatively great and I question whether a racer could engage the forebody of an edged ski without also engaging the rest of the ski. The torsional rigidity of the ski would tend to argue against this happening. Even if you could do this, why would you want to? Now, I can understand why a racer might want to transfer the center of pressure slightly forward, perhaps in order to enhance the early bending of the ski as I described above in order to modify early turn shape but I question whether this is really "tip engagement" as the term has long been used. I would further question whether there really is any genuine attempt to engage any part of the ski selectively. Ski shapes are such today that edge engagement of the whole ski, together with bending provide the geometry used in a carved race turn. Of course I'm not arguing against lateral learning. Any old thing you can do to a ski will likely be useful at some time. I am only discussing the ideal efficient technique of a modern racing turn, what any racer might aspire to in order to win races, not something anyone might want to resort to in appropriate circumstances. What say you?
Well I think the notion of engaging the entire ski makes sense. Certainly if we overload the tips to the point where the balance point is shifted too far forward then the tails will break loose and the ski will skid.
When we talk about old straight skis it depends on exactly what time period we are talking about. Straight skis from Stenmark's era were different from those of Tomba's era. Knee and hip angulation were the catalyst of those turns and over time the release shifted from being upward (lots of rotary) to more of a cross-over, release down the hill. If a skier tried to use inclination in all but a high speed down hill turn they were inviting disaster. When people talk about straight skis they tend to lump it together as one "era", when in reality there are different eras and as the equipment evolved so did the technical application. Watch the following video's:
I couldn't find a video of Tomba from early 90's but maybe someone else can. There will be a discernable difference in the techinque from the Stenmark video, yet they were both on "straight skis".
We are seeking to engage the entire ski but the reason such an emphasis is placed on the the tip is because the tip draws the ski (and skier) into the arc. Its a good reality check, if the tip isn't engaged then the skier will be going along for the ride with the pressure being developed in a more abrupt fashion at the bottom of the arc (skid). In conclusion, we can skid by applying too much pressure in the begginning and also by not applying enough pressure in the begginning. I suppose a coach or instructor could choose to address this in different ways (verbage) with their students, but the fact is that the majority of skiers are not using their tips effectively when transitioning from one turn to the next. Since the ski is moving down the hill it would make sense for the front of the the ski to engage first followed by the rest of the body, but the reality is that the whole ski is being used. If its not, then the resulting turn be less than optimal.
Regards,
Justin

### skidding not carving

some thoughts on loading the tip so excessively that the tails wash out.

i think lots of people ski such that the tails wash out. but, imo, its not excessive tip loading that is to be blame but rather:

excessive rotary (in the long direction of the ski)
insufficient edge angles
heel pushing in the bottom of the turn

conceptually i can see "too much" pressure on the tips as leading to tails washing out, but i havent seen it in practice. (but i'm NOT a racer)
Quote:
 Originally Posted by oisin Yes, but this amounts to engaging the whole ski, whether bent or not, not selective engagement of some part of the ski.
Yes, if done properly. However getting sufficient weight on the front of the ski to bend it while still being able to engage the entire ski as it enters the turn is not an easy thing to do properly on hard snow with the old stiff skis.
Tomba Slalom 1992 Kitzbuhel, 1994 Lech. Spectacular Recovery in Lech Slalom here. Italian Commentary:

Here's a gs race from Bormio, IT in 1995: (Skiing starts at approx. 1 min.)

Thanks Tog, I'm going to have to wait until I can get to a high speed connection to see the video clips. JBM, I think I had straight skis of the earlier (Stenmark) era in mind. They were stiffer and tended to be skiied in a more upright position with knee angulation being far more common. That is where, I am guessing, the term "tip engagement originated. The last days of the straight slalom skis had skis that were quite bendy and could be skiied more like today's technique. I'm curious, you indicated that the ski tip "draws" the skier into the arc. Are you speaking metaphorically? Do you say that just because the ski tip is in front of the rest of the ski and the skier? How exactly does it "draw" the skier? What exactly do you mean by the tip being engaged? If by that you mean effective edge grip then I don't understand. If edges are engaged by tipping the ski, as I understand it, how can you engage one part of the ski without engaging all of it? Are you saying that the pressure distribution is greatest at the tip? Why would direction of travel cause one part of the ski to engage before another?

Sorry if I seem to be harping on this one topic. I am trying to understand what people think they mean when they use these terms and whether, in fact, they are appropriate or even relevent to todays ski technique.

A note of personal explanation: When I was teaching skiing I was frequently dismayed at the sorry disarray of ski instructor training that I witnessed. One factor, I felt, was the use of terms for which a common understanding was lacking. People would often seem to be talking right over one another and misunderstandings often seemed attributable to differing understandngs of terms. Having said that, I better look up one of my old PSIA bibles and see what it has to say.
A ski going around a turn is a little bit like train going around a bend. The engine gets there first and the rest of the train follows in the same tracks. With the skis, however, the engine is laying the tracks.
Quote:
 Originally Posted by Ghost A ski going around a turn is a little bit like train going around a bend. The engine gets there first and the rest of the train follows in the same tracks. With the skis, however, the engine is laying the tracks.
When you lay your ski over does the front of the ski lay over before the back? If so those would be funnyskis. When I lay my ski over the front and rear are tipped simultaneously. No doubt the front gets there before the rear, unless something disastrous is happening, but I don't see what that has to do with what we are discussing.
Perhaps my words are not clear enough. Maybe think of this and something will spring to mind. When you look at your railroad tracks in the snow, does not the apex have a sharper radius than the beginning of the turn? Are not your ski tips in the apex before the middle of your skis? Just as the front of the train draws the rest of the train around the curved track, the ski tips leads the turn, more so as it is making the first cut at the platform the ski rides on through the turn.
Maybe this essay by Olle Larsson wil shed some light.

Pay special attention to the subject towards the end of the article under the heading:

How WC Racers Carve with short Slalom skis and all info thereafter! I have posted this before long ago in a discussion on holding the inside foot back.

Olle's explantion about getting forward and bending the forebody of the ski is very germane to the conversation

Short Story

(Ed. note) This article was written by Olle Larsson and published in "Ski Racing" magazine in the spring of 2000. Although slalom skiing has changed even since then, the article presents a very interesting explanation of modern slalom technique. Olle Larsson is an experienced coach and an author of many publications on ski technique. His full biography could be found in "Coaching Hall of Fame".
Because they carve so well, short skis increase skier's lateral balance; they also demand superior fore and aft balance.

Since ski racing began, skiers have been preoccupied with carving rather than skidding turns. Carving turns is not only faster, but the increased balance that comes from carving can make both the recreational skier and the downhill racer traveling at over 100 kilometers per hour feel more secure.
Male and female World Cup racers using skis 160-175 cm in length are greatly increasing their chances of carving turns. Every racer that has discovered this readily accepts the short time required to adapt his or her technique to these skis. Olympic Champion Pernilla Wiberg stated that it took her just a few runs to get used to them. Other world class racers report similar experiences. It is now evident that by simply changing skis, the racer can in a few short months, improve his or her carving in a way that would formerly, perhaps have taken years. Another added benefit is that in certain situations these shorter skis may prove to be safer for the knees. In case of a loss of balance that forces the skier back and into a seated position, the short new skis will often react with an upward lift of the ski tips. The lift of the tips will decrease the pressure on the knees and expose the ligaments to less physical stress.

The shape of slalom tracks look like giant slalom tracks

The slalom ski tracks that we see today indicate to us that we have entered into a new era of ski racing. Slalom skiing has changed forever! The extensive side cut of short slalom skis produces tracks that look like small giant slalom tracks. The improved carving and balance benefits both ski racer and recreational skier alike. Skiers will most likely feel the greatest improvement on steep groomed slopes where even high caliber racers have difficulty avoiding skidded turns. These new skis will also give the gifted giant slalom skier who has difficulties with slalom a chance to improve in that event.

This photo shows a small radius turn produced by short slalom skis on an intermediate to steep slope. This track is the combined result of a short slalom ski (165 cm.) with a modern side cut and good ski technique. The short ski enhances maneuverability. It is easier and faster for the skier to twist and pivot the ski between turns, if necessary. These benefits will result in faster skiing with less chance of skiing out of the racecourse. In the women's World Cup race where these photos were taken only 4 athletes out of 60 starters did not finish. In the second run only 1 athlete out of 30 went out, which also result in increased safety. How is this track made? Skiers must direct their skis on a line that will allow them to carve. The radius of the turn cannot be smaller than the ski can carve and hold. To successfully ski the ideal line it is essential for racers to look a minimum of two to three gates ahead. Do not worry if you cannot clearly see the closest gate when you look far ahead. Peripheral vision provides you with sufficient awareness of its presence. This track tells us that the skier went from one arcing turn to another with little pivoting of the skis between the arc. If the slope is steep it is essential to redirect the skis by pivoting them between turns to obtain sufficient direction change for the next turn. The turn is finished soon after the gate. As the ski was placed on edge the racer did not use excessive muscular force that could have resulted in skidding. Instead, by relaxing she did not interfere with the carving capacity of the ski. It appears that the skier is placing all the pressure on the outside ski. There is no visible evidence of carving on the inside ski.

In this photo we notice how the racer went too straight at the gate and thus started the turn much later. As a result, the racer must pivot or twist the skis around when the ski should be carving. The resulting skid and loss of balance produces a slower performance. The red dot is the location where the racer in figure 1 started the turn. Poor line choice is the most common reason for slow times in slalom racing. Surprisingly enough, racers that ski too straight at the gate often make this mistake at the first gate in the course. Unless the hill is very flat, using this direct line probably requires a ski half as long as even the shortest skis.

This illustrates the two superimposed tracks. A illustrates the tracks of the carved turns and B those of the skidded turn. We can conclude that the direct, straighter line (B) is slower because the skidding decelerated the skier. Paradoxically, the skier travels a shorter distance in B. Skier B must edge the skis much more aggressively while skier A will position the skis on edge with a smaller angle which is more desirable.

What if you try to ski the good line but can't maintain it?

It may be the case that even if you attempted to ski the line of skier A it would be very difficult to carve turns that perfectly. This difficulty would be compounded on a steeper slope. Clearly, your skiing ability still plays an important part in all of this.
How the world cup ski racers carve with short slalom skis?

Calm upper body.

In photos 1- 4 Bakke keeps her upper body bent forward slightly while the shoulders are kept rather horizontal. The legs move from one side of her body to other. The upper body is almost motionless.

Less up-unweighting.

On moderate slopes there is less vertical extension of the hip (from extending the legs) as opposed to the classical technique used with longer slalom skis just two years ago. The hips/pelvis are kept about the same distance from the slope throughout the photos. The pressure distribution is therefore more even between the ski edge and the snow.
Forward body position.

A forward body position entering the turn is of utmost importance. Bakke's forward body position makes the outside ski's front half bend more than the tail. This forward pressure will lead the ski into quick and tight radius carves. This forward body position exerts great pressure on the tibia against the tongue of the boot, which in turn bends the front of the ski. The skier must be able to bend the ankle in the ski boot. However, at a certain point the ski boot must stop bending forward. It is at this time maximum pressure is transferred to the front of the ski. Her pelvis is forward and noticeably ahead of her outside foot. To acquire a forward position the racer must hold the inside foot back. Both tibias are bent forward to almost the same degree.

Pivoting the ski.

In the following photos we can see how she pivots the skis, which aligns them for the upcoming turn. If the skis were not pivoted it would not be possible to carve the next turn. Slalom gates that are offset on a steep slope require a greater amount of pivoting.

Forward body position by retraction of the outside ski.

Bakke is repeating the same movements except that she retracts her outside ski. There are two common methods to attain a forward body position at the start of the turn. The racer can either extend the leg, which means that the outside leg is bent very little at the knee. (See extension of Mateo Nana in the following photo sequence). Or a second method, which is very effective when the gates are close together giving the racer little time to extend, is to pull the outside foot back. Notice that in frame 5 Bakke's right knee and foot are ahead of her hip. In frame 7 (the last photo) her right foot is now behind her hip. Top racers have developed the ability to either push the ski forward at the end of the turn or pull it back as seen here. The benefit of this action is to produce pressure on the front of the ski by quickly (in 2-3/10's of a second) getting a forward body position with relatively little muscular effort. When the fore and aft body position is ideal the skier can carve turns in a relaxed way. When it is not, the skis must be forced around causing undesirable body stiffness loss of rhythm and decreased ability to absorb changes in the terrain

The photo here shows Fabrizio Tescari from Italy. Heading into a steep pitch Tescari's forward position makes his skis bend from the tip to the tail (third frame). For the skier to advance forward it is essential to hold the inside foot back. Notice that his left foot is leading well ahead of his right foot (downhill foot) in frame 4. The angle of his two lower legs (tibias) is clearly different while in frames 2 and 3 the tibias have almost parallel angles. To acquire a forward body position correctly positioning the uphill foot is very important. If Tescari had started his turn with his uphill foot positioned ahead of the downhill foot, as demonstrated in frame 4, it would have been difficult to generate pressure on the front of the downhill ski. At the start of the turn, the combination of the uphill foot far ahead of the downhill foot and pressure on the uphill ski will stop the skier from getting a forward position.
Quote:
 Originally Posted by Ghost Perhaps my words are not clear enough. Maybe think of this and something will spring to mind. When you look at your railroad tracks in the snow, does not the apex have a sharper radius than the beginning of the turn? Are not your ski tips in the apex before the middle of your skis? Just as the front of the train draws the rest of the train around the curved track, the ski tips leads the turn, more so as it is making the first cut at the platform the ski rides on through the turn.
The locomotive at the front of the train draws the train behind it because it is literally pulling it. I don't see any comparable mechanical action at work on my skis. Gravity is pulling equally at the entire ski. I do see the metaphorical allusion however but I don't know that it helps clarify what is actually happening. Also I don't beleive the front of the ski is cutting first. both front and rear are cutting simultaneously. (time and space)
Tomba was pretty damn good eh?

Quote:
 Originally Posted by Atomicman Because they carve so well, short skis increase skier's lateral balance; they also demand superior fore and aft balance. -from Olle Larsen article.-Well it's alway interesting to note that when "fore and aft balance" is mentioned the fore part is usually focused on and never the aft. From all the photos posted in this thread, it's quite clear that there is a wide range of fore/aft states.-These three photos from the Olle Larsen article clearly show turns started in an "aft" state. In the two slalom photos, the turns are finished "forward" and then started "aft". Apparently though, according to Atomicman (and correct if I'm wrong here), when racing one is always supposed to start a turn "forward" with great pressure on the forebody of the ski.
Saying "Get Forward" is vague and nebulous advice. It is never "wrong" since there are always times to start a turn in the forward (in boot tongues) position and when in a high energy carved turn where the skis are deeply flexed. In that state, you are about to be "launched" when the edges are released so to not be forward is both courting disaster and reducing the effect of throwing the body into the next turn.

Now how to "get forward" and when, where in the turn, and how much - that is what I would call "race coaching" or "high level ski coaching".

Clearly speed on skis is fastest when the pressure is somewhat aft - more on the tail of the ski. So to be "faster" should the thought be "how far aft can I go?" Of course speed is useless if you don't make the turn for the gate, have to take such a wide line to maintain speed in the more aft "faster" state, or can't handle the forces at the bottom of the turn. So actually being quicker through a series of turns may not have a simple solution.

Quote:
 Also I don't beleive the front of the ski is cutting first. both front and rear are cutting simultaneously. - oisin
Well this is an interesting question. Since we are going forward, I guess we could say the front of the ski carves first. One can also carve more with the front and let the tails wash out.

Isn't the question really about how the ski flexes though? If one is pressuring the ski in the middle and the ski is flexed and turning is it any different to move the pressure forward? Will the ski bend differently and will the front of the ski have a tighter radius then the back?

For one thing, putting more pressure on the forebody of the ski on a snow surface that is not smooth or flat, will at least insure that the front of the ski engages at the earliest possible time. If the tip is running over little bumps for example, and one is not pressuring the front of the ski, it will be more likely to not start carving immediately. So just in this aspect, if the desire is to start carving a tight turn immediately, it would be better to pressure the front of the ski.

The question still remains though, can one carve a "tighter" turn by pressuring forward at the begining of the turn or is it just a qucker start of the turn? Perhaps even if it is just a quicker start the turn will be tighter.

Possibly these Images could be looked at to determine:

Resi Steigler Aare slalom 2006 2nd run / Anja Paerson same turn (I think)

Andre Myhrer 2006 slalom Beaver Creek 1st run

I guess this is maybe where our viewpoint differs. I look at these images and say the turn is finished aft and begun forward.

I don't think you can call it a new turn until after the trnasition has been completed, not before. So again these shots show crossunder in a retracted position but as I believe Olle aslo points out that position is the end of the previous turn and the turns are started forward.

No question that pressuring the forebody of the ski more tightens the arc, as Olle points out.
In some ways I agree with you.

If we look at the top two slaloms from the Olle article:
Left image:
1st at gate: clearly forward.
2nd: neutral
3rd: feet forward body inside (some would call this "aft")
Right image:
1st at gate: clearly forward
2nd near transition: slightly forward
3rd: feet starting to go ahead, body inside

The below images I posted for trying to see the skis flexing characteristics - can we see if they bend evenly always, or more at the tip when pressured forward or biting at start of turn?

In terms of fore/aft though:
Resi: (1st photo in dark suit w/ears on helmet)
1st image: clearly aft at transition
2nd: skis pointed other direction, she's inside turn. Position not commonly called "forward"
5th: at transition. Neutral to slightly aft
6th: inside turn now and she's getting forward!
last: well, let's call this forward!, though you could say it balances to neutral between inside and outside feet.

It's pretty hard to tell about the flex esp. with the effect of seeing more of the width of the ski in front. (Looking at outside ski here) 2nd to last: tip and tail close to equal radius possibly tip more flexed. Last: I guess I'd say tip is more flexed.
(Where's beyond with his instruments?)

Last photo of Myhrer:
goes into first gate "aft" feet in front, body inside.

At transition: aft
2nd to last: skis have pivoted, he's inside turn. Neutral to forward.
last: forward ho!

In terms of flex, on 2nd to last image, it appears that the tip is biting and front of ski is flexed more than tail but again it's hard to read.

(People should feel free to agree/disagree with these assements btw.)
oisin,
I think you're also assuming that skis flex "evenly" when they may or may not. It used to be common in ski reviews, just before the shaped era (and possibly way before-don't know), to publish the flex charateristics of tip,tail and whole ski. In general slalom skis would have a softer flex at the tip and a stiffer tail.

As a quick example of a ski today, the Stockli Stormrider DP has a relatively soft tip and tail and a stiffer middle. When you flex it in the store, (tail in carpet one hand on tip and pushing down in center), it does not make a "fair curve". (Smooth curve without discontinuities) The tip and tail will have a similar curve and the middle will be much flatter.

As an extreme example of tip engagement, a "tip stand" where you dig the very tip in the snow and then balance with poles and tails are in the air.
Clearly the tip will bend much more than the rest of the ski. The tail will probably have little curve at all.

General note on "tip engagement": to engage tip, lift tail!
Quote:
 Originally Posted by Tog ..........................Isn't the question really about how the ski flexes though?
Yes, thats what I think. Pressure distribution can cause the ski to be flexed most where the force is concentrated. This point can be moved fore and aft. Its also possible that moving forward allows the skier to harness some of his own momentum to cause the ski to flex early, before a significant amount of force is otherwise available to bend the ski. )If this is the case it may be that bending the forebody is not the objective so much as imparting the force of the skiers own momentum relative to the skis in order to simply bend them. Think of the skier's body rushing forward faster than the skis and impacting the ski via the ski boot to cause it to flex.) The timing of when and where this concentration occurs is part of the skier's means of adjusting overall turn shape and part of the skier's tactics. Its evident from the photo montages that the racers we've seen are electing to ski with quite a range of fore and aft movement. I don't doubt that these skiers could, if they wished, ski virtually every turn in a more or less centered stance. I have to conclude that doing otherwise is intentional and presumably faster.
Quote:
 Originally Posted by oisin The locomotive at the front of the train draws the train behind it because it is literally pulling it. I don't see any comparable mechanical action at work on my skis. Gravity is pulling equally at the entire ski. I do see the metaphorical allusion however but I don't know that it helps clarify what is actually happening. Also I don't beleive the front of the ski is cutting first. both front and rear are cutting simultaneously. (time and space)
Now consider the train engine at the back pushing the train. The first car will still draw the car behind it into the corner, as will the rails. With the ski the tip is the first agent in carving the platform (equivalent to the rails) upon which the turn is made.
Quote:
 Originally Posted by Tog oisin, I think you're also assuming that skis flex "evenly" when they may or may not. It used to be common in ski reviews, just before the shaped era (and possibly way before-don't know), to publish the flex charateristics of tip,tail and whole ski. In general slalom skis would have a softer flex at the tip and a stiffer tail. ................................As an extreme example of tip engagement, a "tip stand" where you dig the very tip in the snow and then balance with poles and tails are in the air. Clearly the tip will bend much more than the rest of the ski. The tail will probably have little curve at all. General note on "tip engagement": to engage tip, lift tail!
Tog I agree with you that skis are engineered to have complex flex characteristics. I think pressure distribution (and the associated timing thereof) is part of ski technique. I just don't think that calling it "tip engagement" is anymore a clear or accurate descripion of what we normally do. I don't doubt you can jam the ski tip into something and cause it to decelerate, causing the rest of the ski to rotate or pivot around it. I just don't think that is something a skier normally wants to do. As I've said before, I'm far from opposed to lateral learning. I think an advanced skiershould strive to learn everything and anything (while maintaining a focus on efficient technique). Thers no telling when it may become useful. I'm thinking of that amazing recovery Bode Miller made in the Olympic downhill at Snowbasin. I like to think of it as a spectacular display of skills acquired through lateral learning.
Quote:
 Originally Posted by Ghost Now consider the train engine at the back pushing the train. The first car will still draw the car behind it into the corner, as will the rails. With the ski the tip is the first agent in carving the platform (equivalent to the rails) upon which the turn is made.
i think we're just speaking past one another here, electing to use language in different ways. The first car in your example is literally being pushed forward by a force exerted upon it through all the cars behind it by the locomotive at the rear. the cars in between are experiencing considerable compressive force in such an instance as a result. normally the locomotive at the front would be pulling, imparting a tensile force to the cars behind. On the other hand you can elect to visualize the leading car as "drawing the others forward" since this is what imagination may suggest is happening. I'm fond of such poetic imagery and it can be useful in ski teaching but such imprecision and ambiguity in the technical training of instructors and coaches can and does lead to faulty understanding.

Similarly, while it may appear that the ski tip is thefirst portion of the ski to be carving, since it appears to be the first to arrive at uncut snow, you have to ask what is concurrently happening under the rest of the ski. Since the rest of the ski is also equally edged and has a similar if not equal amount of force acting upon it, i would suggest it is also carving simultaneous with the front of the ski. This is simultaneity in time if not in space, I suppose. We imagine the action occurring at the front of the ski is occuring first because we associate what is happening with forward movement through space. We imagine the action is first ocurring where we can first see it appear to occur. I suppose there is an enhanced cutting force at work due to forward movement, just as a slicing blade is more effective than a chopping blade on, lets say meat and vegetables but i would guess this merely results in increased efficiency (assuming its even a factor in ski carving). It isn't necessarily the cause of a carve. In any case, the rest of the ski is also slicing the surface concurrent with the front section so the argument is moot.
Yes, the rest of the ski is carving. Nobody is arguing against that. That is the first approximation model. You have to see beyond that and see how the ski, bit by bit changes into a curve as time goes on and as the ski moves into the turn, how each part of the ski is changing in time and space. As the ski moves through the apex, pressure will not be equal on the whole ski. The point of maximum pressure will change. The ski does not suddenly go from not turning to turning with a sudden whole sale change in the skis shape, but the skis change shape gradually, with the first change occurring at the tip. Perhaps thinking of how a tire deforms as a motorbike is put into a corner will help. If you don't get it now, I give up .
I believe there is another aspect here that oisin is ignoring. That is that the majority of skis have a considerably wider tip then tail. This is called Taper Angle

Under oisin's statement that the entire ski is engaged and pressure was equal along the entire ski (although I believe this is not the case but I will agree here for this example) the tip will make a much tigher arc since it is considerably more curve to it. Add in the concept used by many manufacturers that the tip is even wider forward of the natural contact point when the ski is laying flat , (think here of Volkl's 3d sidecut) and you the tip engagement is even more prononced then the tail once the ski is tipped on edge. I also believe this supports Ghosts train theory. In a purely carved turn the tail follws in the exact path the tip has established.
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 Originally Posted by oisin Yes, thats what I think. Pressure distribution can cause the ski to be flexed most where the force is concentrated. This point can be moved fore and aft.....Its also possible that moving forward allows the skier to harness some of his own momentum to cause the ski to flex early, before a significant amount of force is otherwise available to bend the ski. )If this is the case it may be that bending the forebody is not the objective so much as imparting the force of the skiers own momentum relative to the skis in order to simply bend them. ...Think of the skier's body rushing forward faster than the skis and impacting the ski via the ski boot to cause it to flex.) The timing of when and where this concentration occurs is part of the skier's means of adjusting overall turn shape and part of the skier's tactics. Its evident from the photo montages that the racers we've seen are electing to ski with quite a range of fore and aft movement. I don't doubt that these skiers could, if they wished, ski virtually every turn in a more or less centered stance. I have to conclude that doing otherwise is intentional and presumably faster.
I agree with everything here. The bold part is perhaps where we're all saying the same thing or not. Saying "simply bend them" I guess is the issue of discussion. It is perhaps semantics. I think we would all agree that "engaging the tip" is really supposed to mean "starting the ski to carve". Essentially, "laying the track" for a carve, even if it means that the tails will not follow the track but may be purposefully allowed to skid sideways. Perhaps even more simply, starting the ski to change direction quickly.

Atomicman, since the ski is essentially a one radius curve, (assuming it's a simple 1 radius sidecut), the front of the ski wouldn't have any tighter arc than the rear. I think the flex characteristics are more of an influence here. I guess the question is, in a pure carved turn are the forces acting on the tip of the ski different from the forces on the tail of the ski?

It's interesting you bring up "taper angle" because I was going to bring up the same thing in respect to "reverse taper angle". There the tail is wider than the tip and is referred to as a "pusher ski".
I believe Salomon made a gs ski in roughly 00/01 or 01/02 that had a different shape than the usual. I don't think it was actually reverse taper (I may be wrong) but compared to other gs skis the tip was narrower and the tall was wider. I believe the idea was to give more power to the end of the turn and make initiation "easier".

Yes, I found a reference on Skinet:
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 Or, consider one of the smoothest GS skis in the test, the gently explosive, uniquely shaped Salomon Equipe 10 2V Poweraxe (\$725, 172-188, 97-66-100). "Easy and spunky," McKinney said, "but still full of energy." The 2V's 66-mm waist is wide and stable, and its tail is actually 3 mm wider than its tipâ€”great for "milking" the end of the turn for speed. Delliquadri loved its "unique feelâ€”locked into the snow, but not stuck. And in the course? Wow, automatic." Great even for first-time Masters racers.
http://www.skinet.com/article.jsp?ID=1000047417

As a side note to this. In the early 90's, I think 92/3, Elan tested it's new "parabolic" skis at Okemo, VT. Those were the ones with ridiculously big sidecuts and huge tips and tails.
I've talked to someone who was involved in the test. They had all different lengths but I remember him talking about the 200cm skis. Basically, they were "terrifying" because the 200cm ski with that much sidecut would just "lock in" to the turn and it was difficult to release. If you were making a turn with the body inside the turn you would quickly find yourself heading for the woods struggling to let go of the edge.
Would that not only be true if the tip and tail dimensions were identical(some skis are and consequently are much less versatile in reference to turn shape) and the ski was perfectly symmetrical.

So you are saying the shape of sidecut has no bearing on turn shape?:

You have heard the phrase "the wide tip draws you into the turn?"

Also consider a ski with the tip narrower then the tail (Wasn't that the case with the Salomn you mentioned?) that would have quite a different result would it not?

I skied that Salomon! maybe one of the worst race skis I have ever skied on. Absolutly horrible. I beleive they only made it 2 seasons! The french must be slow learners.
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 Would that not only be true if the tip and tail dimensions were identical(some skis are and consequently are much less versatile in reference to turn shape) and the ski was perfectly symmetrical. -Atomicman
I guess that was in answer to this statement:
Quote:
 Atomicman, since the ski is essentially a one radius curve, (assuming it's a simple 1 radius sidecut), the front of the ski wouldn't have any tighter arc than the rear.
Ok, I see what you're saying and I believe now my statement was wrong. I think perhaps you are right about that issue. It's confusing though since the sidecut is supposedly circular.

But if we accept that then doesn't that mean that when the ski is flexed in a carved turn where the skier is centered, the curve produced in the ski will not be symmetrical? That is the curve from the middle of the foot to the tip will not be the same as the curve from the middle to the tail.

In this issue one can see the importance of binding placement.

Quote:
 I skied that Salomon! maybe one of the worst race skis I have ever skied on. Absolutly horrible. I beleive they only made it 2 seasons! The french must be slow learners.
Oddly, I skied that in France for one day in the summer of '01. I remember the ski's turning as being odd, but that was overshadowed by the first time skiing on a plate. It had that large aluminum Salomom plate hinged I believe a bit in from the front and back. I was amazed at the effect of that thing in powering through slush and it was definitely the begining of plate addiction.
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 Originally Posted by Ghost Yes, the rest of the ski is carving. Nobody is arguing against that. That is the first approximation model. You have to see beyond that and see how the ski, bit by bit changes into a curve as time goes on and as the ski moves into the turn, how each part of the ski is changing in time and space. As the ski moves through the apex, pressure will not be equal on the whole ski. The point of maximum pressure will change. The ski does not suddenly go from not turning to turning with a sudden whole sale change in the skis shape, but the skis change shape gradually, with the first change occurring at the tip. Perhaps thinking of how a tire deforms as a motorbike is put into a corner will help. If you don't get it now, I give up .
I follow the analogy, and I follow the intent. However, I doubt it's truth.

Why should the tail follow the tip when the maximum pressure is on the tip? Are you suggesting that the bend radius of the tail is going to be determined by the bend radius of the fore-body of the ski?

This model is limited by the bend radius of the tail -- it is not like a train, where all couplings are equally flexible.

IMO, the tip will engage, and the tails will skid, until there is sufficient pressure on the tails for them to engage as well. There is no following of tail to tip throughout, there is creation of steerging angle by deflection of the tip from the direction of travel. Then there is wholesale ski engagement as the pressure distribution allows for the entire ski to engage......
Quote:
 Originally Posted by Ghost Yes, the rest of the ski is carving. Nobody is arguing against that. That is the first approximation model. You have to see beyond that and see how the ski, bit by bit changes into a curve as time goes on and as the ski moves into the turn, how each part of the ski is changing in time and space. As the ski moves through the apex, pressure will not be equal on the whole ski. The point of maximum pressure will change. The ski does not suddenly go from not turning to turning with a sudden whole sale change in the skis shape, but the skis change shape gradually, with the first change occurring at the tip. Perhaps thinking of how a tire deforms as a motorbike is put into a corner will help. If you don't get it now, I give up .
Why do you think the bend begins at the tip? This would seem to suggest the ski is bending in response to the ski tip encountering something rather than force exerted against the ski. If you "stand" against the ski with great force does it begin to change shape at the tip? No, it deflects in reponse to the force exerted which will be greatest beneath the foot.I am trying hard to "get" it but your logic escapes me.
Quote:
 Originally Posted by Atomicman I believe there is another aspect here that oisin is ignoring. That is that the majority of skis have a considerably wider tip then tail. This is called Taper Angle Under oisin's statement that the entire ski is engaged and pressure was equal along the entire ski (although I believe this is not the case but I will agree here for this example) the tip will make a much tigher arc since it is considerably more curve to it. Add in the concept used by many manufacturers that the tip is even wider forward of the natural contact point when the ski is laying flat , (think here of Volkl's 3d sidecut) and you the tip engagement is even more prononced then the tail once the ski is tipped on edge. I also believe this supports Ghosts train theory. In a purely carved turn the tail follws in the exact path the tip has established.
Sorry I didn't mean to indicate pressure is necessarily equal throughout the ski. I think pressure distribution and managing that ie moving it fore and aft is still an issue with contemporary skis. I tried to deal with the issue of wider ski tips and the departure angle they create in an earlier post. I think the term "tip engagement" originated in an era when skitips were wider than the rest of the ski and ski tails fairly narrow. The problem I have with the concept is that with today's skis the tails are also quite wide. When you engage the edge of the forebody by tipping the ski you also cannot help engaging the tail which tapers the opposite direction. Even with pressure concentated towards the front of the ski the tail is engaged to some degree because the ski is edged ie tipped. I'm not saying you could not get the tail to break away and skid but I am asking why you would normally want to. Ie, except in those situations when you wish to scrub speed or require a sudden pivoting change of ski direction, why not harness the entire ski in carving the turn? This is why I question the term "tip engagement' in the ideal turn since I think you are no longer attempting to engage one portion of the ski selectively but instead the entire ski.
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