@under a new name, well I'm relying purely on the accuracy of the app. I did it 3 times and each day the speed was within 1mph so at least it showed 2 things - i) consistent recording of speed and ii) I couldn't go any faster than that end of!! for what its worth, not that this is in anyway a boast as I am a decidedly average skier - but nobody went past me whilst I was doing this.
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Obviously A snowHead isn't a real person
In the YouTube video the top speed I saw reported was 145kph which is around 90mph.
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Well, the person's real but it's just a made up name, see?
Quote:
say 40m ?
Exactly......at least I should think! So if anyone at those sorts of speeds suddenly needs to stop in an emergency I bet they don't ski always with that amount of clear stopping distance in front of them. You only have to watch the distance it takes the pro. skiers to stop at the end of a World Cup course to see that you can't suddenly stop if you need to. Mind you I wonder if a number of folks are confusing their kph with their mph!
@foxtrotzulu, depends on the hill, think the fastest is just over 100mph at Kitzbuehel a few years back, but that's a bonkers hill and not like anything on the women's circuit, or like most people ski recreationally. For the most part there will be sections where the men might hit 120-130kph, but that's on an icy, race prepped slope. Women's events are slower.
At about 12:40 in this video is Max Franz's run, he's not hanging around but hits a quick speed trap at 128kph, which is about 80mph.
@under a new name, The distances you quote, are they how long you estimate it would take to reach those speeds? If so, then they sound about right. What point are your trying to make with those distances?
@under a new name, have you tried the flegere speed course? I've no idea if it's right, all I know is that it consistently shows my speed as 105-110kph based on the speed gun at the bottom, and this correlates with the side markers that show what speed you'll do depending on launch point.
What I can also say is that whatever speed that really is, it is far faster than I would want to go with anyone else around on anything other than a flat groomed run with a big stopping area. I'm just hanging on for dear life!
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Then you can post your own questions or snow reports...
@SnoodlesMcFlude, I think the 100mph figure is pretty exceptional, but it does highlight the point that the 68mph record achieved by UANN’s friends doesn’t seem to make sense. I suspect the former is a snapshot and the latter is a timed average or something.
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@Adamski, Not doubting what you're seeing, not sure the apps correct. Not worried either way... -)
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@foxtrotzulu, no. Not at all. Apart from Lake Placid being quite a few years ago and averages are a bit up... The speeds are fairly variable, however, a. their peak is way higher than any recreational skier would be getting close to and b. have you ever entered a steep pitch carrying even say, 30kph? I mean, the sort of pitch you'd normally stop at the top of and start off quite gingerly?
If you consider the Lauberhorn, course fastest average 66mph with 100mph peaks suggesting a fair bit of it is somewhere sub 66mph...
I will happily admit I am a crap racer, but I've done the Inferno quite a few times now and the middle section is described as where you "have no need of additional gravity"...
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@foxtrotzulu, it was my point that 100mph is exceptional (it's the fastest spot on the fastest course), and that 80 is nearer normal at the top of the men's circuit. 68 as a best ever through a speed trap seems slightly slow, but not remarkably so.
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Clocked 86kph on a speed trap around 15 years ago whilst out with a guide. It was directly after that the guide pointed out the potential catastrophic outcome of a collision at that speed whilst not wearing a helmet. Worn one ever since.
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And love to help out and answer questions and of course, read each other's snow reports.
@under a new name, yeh my estimate of the odd 70mph is based on a visual comparison of someone skiing faster than I perceive myself to ski at my top ski track recorded speed of 54 mph. Ski track might be inaccurate to some degree as might my perception of other skiers speed. I think that makes sense. Either way in my opinion I don’t often sustain a speed above 40mph for any great distance nor do most other recreational skiers. The rest is just bullshitometer red zone
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My guess is that when you take a professional and a reasonable recreational skier and put both, in their usual kit, at the top of a nice smooth schuss then the pro will be, say, 15-25 mph faster, but the difference really kicks in when you add in the turns, drops, compressions etc that the difference becomes absolutely huge. My peak speed on a perfect surface might be about 50, but my average down the whole run may be closer to 15mph.
As I’ve said before, I have no reason to doubt the accuracy of ski tracks - especially if you check the data for outliers.
You know it makes sense.
You know it makes sense.
@foxtrotzulu, i think that makes sense.
I’m still thinking 50mph would be or should be scaring the socks of most of us...
Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
@under a new name, @foxtrotzulu, you’ve both hit the nail on the head.
Poster: A snowHead
Poster: A snowHead
Quote:
I’m still thinking 50mph would be or should be scaring the socks of most of us other skiers on the mountain
Fify
Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
If we think 50 mph is scary, just imagine going at about 40mph, on the back of a horse, over 5ft jumps, and when you do come off you are falling from twice your normal height and then getting kicked by all the runners behind. Thank god we aren’t steeplechase jockeys!
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?
under a new name wrote:
@foxtrotzulu, i think that makes sense.
I’m still thinking 50mph would be or should be scaring the socks of most of us...
Many years ago I clocked up some stupidly high speed in a daft place. Never again! I’m not a speed merchant but do enjoy a good schuss now and then. 50mph may risk serious injury, but it’s definitely possible to do it in places where there is zero chance of injuring anyone else. Empty pistes with nobody around and a clear 200m run out or more.
Now that we seem to have, almost, reached a consensus one further thought (which just happens to support my premise ) occurs to me. On the sort of slope that I'm thinking of, and where I assume most of us have achieved our top speed (nice smooth, straight schuss with a long run-out) then I wonder what the results would be in the following circumstances:
1. Professional downhill skier in appropriate kit.
2. Goodish recreational skier in recreational kit.
3. 75kg mannequin with shock absorbing joints etc. fixed in a good tuck position and strapped to a pair of skis at the right angle.
I think we can assume that the pro will beat the recreational skier, if only because of the clothing and 'faster' skis. The question is how the mannequin would fare. Assuming it kept a straight line and didn't fall over, then I'd expect it to do pretty well. In other words, the top speed that most of us record on skitracks is usually in a situation where the need for technique is minimised. The physics are much the same for all three skiers. The differences lie in the courage to start further up the hill, the technique involved in stopping/turning. i.e. going fast in a straight line isn't that hard. It's just a question of what happens at the end of the run or when you come to a curve/bump!
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Anyway, snowHeads is much more fun if you do.
I think that's right but I do think the speed skiing records require a bit more active "suspension" to keep the body position and avoid being shaken about. Not that I've tried it I might add.
I've seen the prepared starts of a few DH courses (including the hahnekamm ) and I wouldn't have the balls to straight line from up there even if I didn't know there were sheet ice off-camber turns with trees waiting for you if you get it badly wrong below
I do think the speed skiing records require a bit more active "suspension" to keep the body position and avoid being shaken about
No doubt!
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Then you can post your own questions or snow reports...
Arguably a mannequin would be better suited to laying the skis on flat and keeping them straight, whereas recreational skier may be slightly on edge or have a slight plough. Although as I’ve got nearly 40kg more than the mannequin I’d probably have a bit more help from gravity
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I've got loads of ski tracks data over several years. If I'm on good empty pistes I regularly see peaks in the mid-high 40s and occasionally 50+ mph but those are not sustained speeds over large distances. My average speed is probably more like 20 something. I don't think it's that difficult for a half decent skier to break 50 mph momentarily in good conditions. I think the data is reasonably accurate too FWIW. As for danger, well I think it's a lot more dangerous at those speeds on a road bike or mountain bike, which again are quite attainable in the right conditions and much easier to verify with a speedometer.
I don't think I've ever clocked anything over 60 mph on ski tracks. Anything north of 50 mph (as recorded) feels plenty quick enough for me and would typically be Vmax anyway on the type of terrain I would feel safe hitting those speeds. Pros doing 60+ down an icy steep DH course are on another planet, as are speed skiers going well over 100 mph. I've never seen any of these 70 mph recreational skiers mentioned above??! That would require straight-lining a pretty steep slope for a start, where any mistake would probably be the end of you.
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@SnoodlesMcFlude,
Quote:
Although as I’ve got nearly 40kg more than the mannequin I’d probably have a bit more help from gravity
Now, here's another discussion we've had before but one I don't think we ever satisfactorily resolved. Does a heavier skier go faster? My instinct says that they carry more momentum, and are therefore faster on the cat tracks, but that they also carry more inertia and will be slower to accelerate. As we know, heavy objects fall at the same speed as light objects. It's only air resistance that makes a difference.
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foxtrotzulu wrote:
@SnoodlesMcFlude,
Quote:
Although as I’ve got nearly 40kg more than the mannequin I’d probably have a bit more help from gravity
Now, here's another discussion we've had before but one I don't think we ever satisfactorily resolved. Does a heavier skier go faster? My instinct says that they carry more momentum, and are therefore faster on the cat tracks, but that they also carry more inertia and will be slower to accelerate. As we know, heavy objects fall at the same speed as light objects. It's only air resistance that makes a difference.
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@foxtrotzulu, Here's some loose data... my son (10 yrs old, 32 kg) vs me (44 years old, 80kg). He's on 140cm skis and I'm on 165, so he's got a lot more ski per unit weight (if that matters). Both of us skiing exactly the same speed-skiing course on the same day, sequential runs.
He maxes out at 92kph (2 runs, identical speed both) and I was 104kph (also 2 runs). His technique is better than mine (in a downhill or GS race he crucifies me) but my surface area to weight ratio is more favourable. My max speed (different date so not comparable) was 110kph when I did the course without a jacket on. Those extra kph feel a lot faster without a jacket.
Next week we will return for a rematch, and he will be in a catsuit vs me in normal gear, so I will provide another datapoint.
The scale and rapidity of tiny adjustments required at these speeds mean that I'm confident the mannequin (or ladyequin) would wipe out every time before getting close to vmax.
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.
Twice I have gone through a speed trap in a facility organised by the resorts, once in VT and the other in Les Arcs IIRC. Both were on bits of piste designed specifically for this activity so a reasonably steep start and designated only for this activity (so no other people to worry about or indeed worry)
One was just below 100 kph and the other just above. It's also consistent with the sort of figures I've had from my Garmin GPS although on the speed trap pistes I did at least wear clothing that was the least wind resistant (i.e. XC tights and no jacket, just a snug technical top). Given that on the DH courses with steep starts the skiers can be doing almost 100kph in 5-6 seconds you don't have to be too concerned about any technique other than keeping your skis flat and parallel for a short period of time. I can quite believe that recreational skiers with DH type skis, fairly low drag clothing and a lack of fear could get up to 120 or even more.
To be frank I was far more scared doing over 90 kph coming down from the Galibier on my road bike than I was doing similar speeds on skis (and I was getting passed by other cyclists)
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So if you're just off somewhere snowy come back and post a snow report of your own and we'll all love you very much
foxtrotzulu wrote:
Now, here's another discussion we've had before but one I don't think we ever satisfactorily resolved. Does a heavier skier go faster?
I don't think it can be easily satisfactorily resolved! I'd have thought that the gradient of the slope would play a part though. Also wind resistance will play a part, so depends on how they carry the weight. I'm also not sure if additional weight (to a point) will help the skis glide better. It certainly seems to be the case that DH pros are bigger than SL pros, but that is probably more down to a power/agility thing than the weight being an advantage.
You know it makes sense.
You know it makes sense.
foxtrotzulu wrote:
@SnoodlesMcFlude,
Quote:
Although as I’ve got nearly 40kg more than the mannequin I’d probably have a bit more help from gravity
Now, here's another discussion we've had before but one I don't think we ever satisfactorily resolved. Does a heavier skier go faster? My instinct says that they carry more momentum, and are therefore faster on the cat tracks, but that they also carry more inertia and will be slower to accelerate. As we know, heavy objects fall at the same speed as light objects. It's only air resistance that makes a difference.
It's been too many years since A level physics but I think the key issue is that the momentum (therefore force) a heavy skier generates as they travel will overcome the friction more than a lighter skier will (assuming all other conditions remain the same)
Of course the heavier skier may have a larger frontal area and hence generate more air resistance...
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@dsoutar,
Quote:
Of course the heavier skier may have a larger frontal area and hence generate more air resistance...
Are you saying that @SnowDave has moobs?
Poster: A snowHead
Poster: A snowHead
dsoutar wrote:
It's been too many years since A level physics but I think the key issue is that the momentum (therefore force) a heavy skier generates as they travel will overcome the friction more than a lighter skier will (assuming all other conditions remain the same)
But the heavier skier will generate more friction to overcome and probably balances out. I really don't think it's clear cut whether a heavier skier would be naturally faster or slower, but there probably isn't very much in it. The main force to consider at high speed is aerodynamic drag rather than skier mass. A lighter skier in a skin suit is going to be quicker than a bigger guy wearing a normal jacket.
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Obviously A snowHead isn't a real person
Speed skiers skis are limited in mass to 15kg I assume because having them heavier is an advantage.
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Well, the person's real but it's just a made up name, see?
From what I have read it does seem to be that weight has a higher significance (at least in this scenario). Also the reason why adding weight to a bobsleigh is banned beyond a prescribed limit
Regarding the weight thing. I remember (from when skis were strapped to your boots and never had brakes) seeing a lot of them shooting down the hill unaccompanied. iirc they did seem to gather a fair amount of speed, I had always assumed it was because there was no load pushing them into the snow, they just whizzed over the surface.
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Anyway, snowHeads is much more fun if you do.
Quote:
on the DH courses with steep starts the skiers can be doing almost 100kph in 5-6 seconds
I don't see many recreational skiers tucking 30 degree slopes...
But the heavier skier will generate more friction to overcome and probably balances out. I really don't think it's clear cut whether a heavier skier would be naturally faster or slower, but there probably isn't very much in it. The main force to consider at high speed is aerodynamic drag rather than skier mass. A lighter skier in a skin suit is going to be quicker than a bigger guy wearing a normal jacket.
Only if the the level of friction is very high compared to the gravitational force parallel to the slope. and that would depend on conditions but essentially slush on a gentle gradient. Most prepared pistes, the level of friction will be negligible.
The other issue is air resistance, which is related to area and not weight. So as long as the heavier skier isn't presenting a much larger profile, the heavier skier will go faster.
Then you can post your own questions or snow reports...
Then you can post your own questions or snow reports...
Penry wrote:
uktrailmonster wrote:
But the heavier skier will generate more friction to overcome and probably balances out. I really don't think it's clear cut whether a heavier skier would be naturally faster or slower, but there probably isn't very much in it. The main force to consider at high speed is aerodynamic drag rather than skier mass. A lighter skier in a skin suit is going to be quicker than a bigger guy wearing a normal jacket.
Only if the the level of friction is very high compared to the gravitational force parallel to the slope. and that would depend on conditions but essentially slush on a gentle gradient. Most prepared pistes, the level of friction will be negligible.
The other issue is air resistance, which is related to area and not weight. So as long as the heavier skier isn't presenting a much larger profile, the heavier skier will go faster.
Remind me again which bit of physics says that the heavier skier will go faster? Assume negligible friction and equal aero drag (air resistance in your words) as you suggest.
After all it is free
After all it is free
primoz wrote:
Blue run doesn't mean much... Both tracks from top of Moelltal glacier are marked as blue, but you can easily come in range of 115-120km/h there. But then again, there's no way you can make 60km/h on blue runs around Alta Badia for example. So marking track as blue, red or black doesn't really mean it actually is steep or not.
I couldn't work out the gradings in alta badia...i did a blue 6/7/8 (can't remember) which was decidedly choppy with all the snow and pretty sketchy in several places and yet the red down from passo gardena which was a joy to ski with only one steep section as it comes down to the bottom of the frara gondola?!
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@uktrailmonster, The bit that says that gravitational force = mass x gravity. There will be a component parallel to the slope.
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@Penry, I think you are conflating
f = m.a
and
F = G (M.m)/r^2
whereby if M is Earth mass and m is body mass a1 = G(M.m1)/R^2.m1 = a2 = G(M.m2)/r^2.m2 - the mass of the body cancels out in both cases so different masses (in a vacuum) fall at the same acceleration.
It is however complicated once you introduce air resistance (proportional to x-sectional area) and dynamic friction ...
FAQ
Poster: A snowHead
) occurs to me. On the sort of slope that I'm thinking of, and where I assume most of us have achieved our top speed (nice smooth, straight schuss with a long run-out) then I wonder what the results would be in the following circumstances:
) and I wouldn't have the balls to straight line from up there even if I didn't know there were sheet ice off-camber turns with trees waiting for you if you get it badly wrong below
