 Poster: A snowHead
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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Masque, 21 pages is spectacularly weird, but like a bad car crash you cant help but slow down and have a look 
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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You need to Login to know who's really who.
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rob@rar, I'll remind you that 'that' was a "1 on 1 teacher/pupil conversation" . . . the geometry that followed had Euclid hammering on the lid of his crypt . . . woe betide some of the posters here if he ever gets out
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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All this cowdoo reminds me of some of the cringeworthy commentary ex F1 drivers often come out with concerning technical aspects of the cars. It's not that they can't drive, they just don't understand the physics. Some recognise this limitation and are prepared to listen to engineers explanations and learn something from it, some are not. Simple as that. V8 is the latter type. No doubt a very good skier, but not very good on the technical understanding. But relying on psuedo physics to explain what is happening will not improve his knowledge.
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uktrailmonster, ah, and there is the twist, I did both pure and applied mathematics, and some people here are hanging their hats on the princilapls of pure mathemtics whereas they should be looking at the principals and ethos of their old applied maths text books. Unless and until we start to ski in vacuums rather than in ski boots the principals of pure mathematics are just that, principals.
With respect to curves of the same radius being parrallel, actually when the radius of each curve is on the same line they are for that one point in time parallel (i.e. you can draw a tangent of both curves and they will be parallel), a bit like a broken clock being exactly right twice a day whereas a clock one second slow will never be right. The curves can be parallel but the notional center of the curve needs to be moving, but whether the arc is actually eliptical or not at this point in time I do not know, but the fact of the matter is that no one probably skis a circle anyway, irrespective of side cut etc. so it is all, err, academic.
V8 has got himself in bit of a muddle at times trying to justify his position by responding to points raised by othere, but surely the issue needs to be looked at as a whole and the generality of what is happening, and whether some one can pick a clever hole in one part of V8s arguments is largely irrelevant when considering the big picture and is just 'point scoring' in my book. Similarly name calling is childish too 
Next page please
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I have been known to have tip lead or broken feet as I have also heard it called.
IF its not excessive does it not help in fore and aft stability?
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| rayscoops wrote: |
| uktrailmonster, ah, and there is the twist, I did both pure and applied mathematics, and some people here are hanging their hats on the princilapls of pure mathemtics whereas they should be looking at the principals and ethos of their old applied maths text books. Unless and until we start to ski in vacuums rather than in ski boots the principals of pure mathematics are just that, principals. |
Classical Mechanics falls under the branch of Applied Mathematics. I kindly refer Mr Rayscoops to "A First Course in Mechanics" by Dr Mary Lunn as an excellent introduction on this matter.  Unfortunately an understanding of mechanics requires a rudimentary knowledge of geometry, so may be a bit beyond most people's views. Some reading up about radii of curvature may also be advised: the arguments stated apply equally to other curves, not just circles. Geometry applies exactly the same on the ski slope as it does in the classroom. Just because you've got some planks of wood attached to your feet and are sliding on snow doesn't put you in a special realm where the laws of physics don't apply.
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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Sideshow_Bob, agreed, geometry never changes and arcs of the same radius can be parallel in certain circumstances, but i thought people were talking about skiing and not having p$ssing contests
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| rayscoops wrote: |
uktrailmonster, ah, and there is the twist, I did both pure and applied mathematics, and some people here are hanging their hats on the princilapls of pure mathemtics whereas they should be looking at the principals and ethos of their old applied maths text books. Unless and until we start to ski in vacuums rather than in ski boots the principals of pure mathematics are just that, principals.
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Applied maths is different from talking rubbish in an arrogant manner. Have you actually read the entire thread, or just skimmed it?
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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| rayscoops wrote: |
| Sideshow_Bob, agreed, geometry never changes and arcs of the same radius can be parallel in certain circumstances, but i thought people were talking about skiing and not having p$ssing contests |
We have been looking in quite minute detail about the body movements necessary to make the skis - both skis - carve as clean a turn as possible. Only if we understand (or even just accept) the geometry - the shapes the skis have to make to make the turn - can we look at the body movements necessary to either make the skis make this shape or otherwise make the turn.
FastMan and others have pondered in detail what happens during the turn and how there are different ways of making a turn that looks like a clean carve, and their posts come from the understanding and appreciation that simply tipping both skis on to the same edge angle and riding them will not result in a totally clean carve with feet fixed width apart throughout the turn. Others argue different.
Now I agree we've all fallen into the trap of arguing the underlying geometry and not the ski motions, but that's because certain people have not understood or accepted the geometry. We should accept that some won't ever agree, but when they come back time and again with further increasingly confrontational accusations that we are wrong we feel compelled to defend our position and deconstruct the counter-arguments presented - quoting a certain person "They have to answer" so I did. Has it become a p$ssing contest? Perhaps it now looks like one, but it certainly wasn't the intention. I can only speak for myself, but I'm not trying to accuse anyone of being stupid or resort to personal attacks, merely attempting to aid in understanding what's going on. Unfortunately we've gone round in circles many times, and I was quite glad when the thread died down a few weeks ago. I'm more than happy to let it die again as I and others are just repeating themselves. Olive branches have been offered a number of times, let's all accept them.
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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uktrailmonster, skimmed it because all the geometry arguments seemed to be incidental at best to the thrust of the discussion - parallel skis ? mathematically possible but practically impossible in all circumstances if measured in scientific terms, therefore the 'as close as possible' remit has to be accepted, but you should be patient and see through the slight contradictions of V8 and embrace the overall issues of 'near or visibly' parallel tracks etc in relation to the real world of skiing
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Sideshow_Bob, got to be another 10 pages though edit - Fastman did try to embrace the principals of the issues being discussed by being flexible and not literal in considering the intent of what people were saying, on both sides, he was truly a gentleman in the debate
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You know it makes sense.
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I've found this thread to be both entertaining and depressing. Some of the maths (generic term in this case) has been excruciatingly misapplied and even worse misstated. But what really squeezes my scrote is the expressed opinion that some individuals are able to refine their technique to produce perfect parallel arcs . . . which is a misnomer in it's own right as they are 'equidistant' separate arcs . . . yet fail to express the biometric feedback and mechanical materials understanding of ski and boot construction to provide reasoned justification for the title of the thread . . .
. . . but the bitchfest has been a little fun to read.
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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| Masque wrote: |
| perfect parallel arcs . . . which is a misnomer in it's own right as they are 'equidistant' separate arcs . . . |
No it's not. "Parallel curves" is a perfectly adequate and appropriate description, and has been so for 350 years. Look at some of the links earlier in the thread for confirmation. I agree though that it's a pity that this thread got derailed (and not for the first time) and the majority of it has had nothing to do with its title. We probably had that covered though by about page 5. (BTW did you intend your last line and an half actually to mean anything at all - as I can't make head nor tail of it - or did you just have another fit of verbal diarrhoea?)
rayscoops. You need to read the thread properly if you want your comments to have any weight. This got derailed when V8 came out with a whole load of demonstrably false statements around pages 3-5 - completely contradicting the Fastman post to which he had linked to on page 1. And I repeat, we have tried pointing out to him on a number of occasions how small the adjustments to his model are to resolve the contradictions, but he has steadfastly rejected them all, preferring to stick instead with his rigid adherence to perfect model and claim instead that the laws of physics and geometry are wrong. Had he said at the outset that he wasn't insisting on the tracks being parallel then we would not have had this argument.
And it's "principles"; "principal" is something completely different.
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Poster: A snowHead
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GrahamN, I think that 'parallel' could only be used if we were blessed/cursed with fixed limbs and no articulated joint at the pelvis (that other thread is developing well) as for that last line . . no-one has shown why inner tip lead is dependent on ankle flex in that leg, differently flexing boots will allow a range of positions . . . some of which may be termed excessive yet be at maximum boot flex. Then there is the flex and torsional rigidity of the inner ski. As the inner ski is further along the turn arc it's angle of attack is greater than the trailing or lower leg and it's ability to cut a clean track will depend on flex, torsional resistance and the force being put into it by the skier. If the skier is backward weighted then that force and lead may be minimal but if the skier is driving hard then that force may require a stiff ski to be pushed forward to engage the tip earlier than a soft flexing ski that will be happy to bend into the carved arc shape without much tip lead at all, assuming that the skiers boots are flexible enough to allow the skiers inner leg to bend at needed hip, knee and ankle angles to keep the tip lead less than excessive.
I've spent much idle time thinking about this and did some experimentation at VT and in my case it is predominantly my boot stiffness and a tendency to ski over the centre with a narrow range of weighting . . . probably a boarding legacy from riding 'duck' and not needing to transfer mass with the level of control required on skis.
What I'm depressed about is that this thread didn't look at the myriad of causes that create 'tip lead' or even what can be described as excessive. I actually feel more secure with large lead but that's at 'cruising' speed but that's because I'm in the back seat. When the pedal goes down I have to reduce it to maintain clean tracks with my mass entering the slope well ahead of my toes. I can do that, not 100% of the time and not instinctively but I still learn something from each run.
This was a fascinating subject destroyed by narrow opinions and petty bickering . . . the Hallmark of 'Epic's' technique threads. As someone who has toes dipped into multiple disciplines and a real desire to gain a reasonable level of competency in all of them I seek enlightenment, not obfuscation.
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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| rayscoops wrote: |
| uktrailmonster, skimmed it because all the geometry arguments seemed to be incidental at best to the thrust of the discussion - parallel skis ? mathematically possible but practically impossible in all circumstances if measured in scientific terms, therefore the 'as close as possible' remit has to be accepted, but you should be patient and see through the slight contradictions of V8 and embrace the overall issues of 'near or visibly' parallel tracks etc in relation to the real world of skiing |
My patience and regard for his opinion (purely in the context of this thread) ran out ages ago I'm afraid. Several clearly more experienced professional skiers attempted to reason with V8 regarding the paradox of his rigid, and in most peoples' view incorrect, "real life skiing model". But to no avail. The usual retort (which has got on pretty much everyone's tits) is to simply invent a ludicrous and poorly thought out psuedo mathematical model and back it up by stating what total ski gods him and his fellow pros are.
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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You need to Login to know who's really who.
You need to Login to know who's really who.
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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skimottaret, that second clip, showing the motion capture from different angles, is very interesting. All bits of the body heading off in different directions at the same time. I'm surprised I can ski if it's that complex!
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rob@rar, do you think he is holding his shins to the same angles +- 1 degree, keeping the skis equidistant apart and not diverging...
pretty cool stuff isnt it. I posted a comment to the guy who posted this stuff on youtube. He did his phd in ski racing body mechanics, will be interested to see if he joins in the debate here
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skimottaret, that is absolutely feckkin brilliant. WOW! I am making a presumption that the "rear" view in the last segment is synthesised? Fantastic. Especially if the force/velocity/acceleration vectors are well modelled. This could be really, really cool. I really do hope it all stacks up.
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skimottaret, brilliant-
so thats it then you were all wrong.
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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Now that is an excellent set of links, and shows all sorts of different things that we postulated on including (to bring it back on topic) some inner tip lead at the start of the turns. I'd be more than interested in reading the paper he wrote!
Now I expect a critique of his racing technique and a long explanation on how this is not how WC skiers ski any more and how he'll never win any races 
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Must be time for another post in this fantastic thread:
Sadly, history is littered with examples of fantastic people, whose vision of reality has been so clouded by their beliefs of maths, physics and fundementals that they forget it is merely a start of an explaination of how real life things work.....
Frank Whittle was sent home after being told by the brilliant physicists at the Air Ministry that his engine would never work, his concept was akin to him lifting himself off the ground by his shoelaces.
The USA Department of Defense, on being told be their own fighter pilots about the capabilities and manouevrebilities of the Japanese Zero fighters, dismissed the tales on the basis that such an aircraft could never be built as it would defy physics.
Our very own Colossus computer that broke WWII codes very nearly didn't get built when Tom Flowers got sent away by the top brass, dismissing his machine as not worthy of building.....
and so it goes on......
Unfortunately, it's quite predictable (and is somewhat reflective on UK industry today) that this pattern is repeated here, and once again, it takes a nice American gentleman to see through the stunted 2D geometry and actually realise what's possible in real life. The other observation is the good ol' pack/mob behaviour that rears it's head from time to time................
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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| Quote: |
it takes a nice American gentleman to see through the stunted 2D geometry and actually realise what's possible in real life.
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who would that be?
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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You see, that's the dangers of skim reading 
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veeeight, hmm this never ending saga hasnt been skim reading it is just mind numbing. Are you refering to Fastman?
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You know it makes sense.
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veeeight, don't forget George Stephenson. Good job he had a better grasp of how things work than some have demonstrated on this thread or else railway lines would only have ever gone in straight lines
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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| veeeight wrote: |
Must be time for another post in this fantastic thread:
Sadly, history is littered with examples of fantastic people, whose vision of reality has been so clouded by their beliefs of maths, physics and fundementals that they forget it is merely a start of an explaination of how real life things work.....
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Obviously a bit off topic now, but isn't it usually the mathematicians and physicists who actually pave the way to better understanding of how things really work? It's usually belief in superstition, religion, politics etc and lack of understanding of maths and physics that usually clouds your vision. It's true that ground breaking physics is often overlooked initially by conservative peers, but I wouldn't exactly put the theories you've presented in this thread in that category.
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Poster: A snowHead
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uktrailmonster, now he puts himself on a par with some of the greatest minds of the 20th century. Anyway, if he can't properly observe what's going on in the youtube examples, then there is no hope for him.
This thread should be sent to the examining organisation which passed him, so that they can state their position on this. They seem to be producing a generation of teachers with no practical grounding in the important areas that enable skiing to be described in the universal language of mathematics. From the ground up, skiing is now shrouded in meaningless jargon, that seems to differ depending on which teacher you get.
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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| veeeight wrote: |
Sadly, history is littered with examples of fantastic people, whose vision of reality has been so clouded by their beliefs of maths, physics and fundementals that they forget it is merely a start of an explaination of how real life things work.....
Frank Whittle was sent home after being told by the brilliant physicists at the Air Ministry that his engine would never work, his concept was akin to him lifting himself off the ground by his shoelaces.
The USA Department of Defense, on being told be their own fighter pilots about the capabilities and manouevrebilities of the Japanese Zero fighters, dismissed the tales on the basis that such an aircraft could never be built as it would defy physics.
Our very own Colossus computer that broke WWII codes very nearly didn't get built when Tom Flowers got sent away by the top brass, dismissing his machine as not worthy of building..... |
Fascinating stuff. Can you tell us which principles of geometry (or any other branch of maths) Whittle and the nameless others tore up?
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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Things are getting boring so I thought I would resurrect some interesting stuff 
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You need to Login to know who's really who.
You need to Login to know who's really who.
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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Frosty the Snowman, Noooooooooooooooooooooooooooooooooooooooooooooo!
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You'll need to Register first of course.
You'll need to Register first of course.
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One can imagine a certain young man's abode knee deep in scrunched up pieces of paper, all with pairs of arcs scrawled on them. Some parallel, some identical, but never parallel and identical.
The laws of geometry are the moderators on this thread, and they cannot be denied!
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So have you yet accepted that the inside ski does not prescribe a smaller radius?
Nevermind the paper - the arcs in the snow tell a different story.
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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Sideshow_Bob, nice collection of drawing compasses there on the wall to the right.
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FAQ
This is a thread for a 1 on 1 teacher/pupil conversation.
