Carving

[Steve]

I would enjoy reading a discussion of platform angle, because although I do basically understand if, I do find it a confusing concept.

 

[François Pugh]

And they mentioned increase tipping angle to decrease turn radius - no need to park and ride.

 

[François Pugh]

I would enjoy reading a discussion of platform angle, because although I do basically understand if, I do find it a confusing concept.

Because platform angle varies with turn forces, which vary with speed and turn size, a good understanding of Newtonian physics and vector addition would help thorough understanding, but there are just a couple of things you need to keep in mind when it comes to carving and platform angle, and you don't need a high-school physics course for that:
1. If you don't tip your ski up to a big enough angle, you will not achieve the platform angle.
2. The faster you go for any given turn, the more you have to tip the skis to achieve the platform angle.
3. The tighter you turn for any given speed, the more you have to tip the skis to achieve the platform angle.
4. You can tip the skis more than required to achieve the platform angle and hold the carve, but not less.
5. Most difficult to understand, for a given ski with a given side-cut radius, there is a limit to how fast you can go and still carve a clean turn of a given radius; as you tip the ski more on edge to achieve the platform angle, the self-steering aspect of the ski dials up a tighter turn. Eventually (because math - the cosine curve gets steeper) you reach the point where the turn dialed up increases the required tipping angle faster than you tipping the skis is closing the gap between the angle you have the skis tipped to and the angle required to achieve the platform angle at the speed you are carrying. That's why they make skis in longer radii for higher speeds.

Number 5 is a good point to keep in mind before you start getting your adrenaline fix by skiing your SL skis at very high speeds. They won't make a clean turn at those speeds, but should they suddenly hook into a bump or rut as you are skidding along at those speeds you will be in a lot of pain - or dead.

 

[LiquidFeet]

Platform angle consists of two imaginary lines that meet. One line extends across the surface of the ski, from side to side, starting where the tipped ski contacts hard snow. The other starts at the point where the tipped ski contacts hard snow and travels up to the body's center of mass. That angle, for the ski to grip on hard snow, needs to be less-than-or-equal-to-90º.

Note that edge angle to the snow is not platform angle. Low edge angle skis can produce pencil-thin lines in the snow if appropriate platform angle is maintained (railroad tracks). It's the relationship of the body to the ski that defines whether the ski will grip not slip and produce narrow tracks, not the ski to the snow.

If the ski is slipping/skidding and it was tipped without being rotated, the problem may be platform angle. To fix platform angle, the skier can move the upper body farther out over the outside ski or bring the outside ski closer up under the body. Either of these, or both together, will reduce the platform angle in the direction that will enable grip. That's all anyone really needs to know.

Some major enemies of that platform angle goal (less-than-or-equal-to-90º) are:
--leaning in/banking/bracing (puts the body too far inside the turn - angulate instead)
--hip-dumping (puts the body too far inside the turn - shorten the inside leg and roll its knee into the turn instead)
--pushing the outside ski to an edge (puts the body too far inside the turn - tip the skis without pushing by flexing the inside leg instead)
--skiing square (makes angulation more difficult so the body ends up too far inside the turn - ski with separation and angulation instead)

Increasing edge angle by flexing the inside leg more can result in a more effective platform angle, since angulation usually results. Angulation will move the body farther out over the outside ski to achieve that elusive platform angle goal. And as @François Pugh points out, speed impacts edge angle requirements.

 

[Steve]

Note that edge angle to the snow is not platform angle. Low edge angle skis can produce pencil-thin lines in the snow if appropriate platform angle is maintained (railroad tracks). It's the relationship of the body to the ski that defines whether the ski will grip not slip and produce narrow tracks, not the ski to the snow.

This clarifies things in a simple way, thanks.

 

[anders_nor]

ref thread on NS... eurocarve or bust!

Also mach schnell for regular carve is the only way us not so young guys can show them kids how its done.

 

[4ster]

Carving is control, pure & simple.
It seems to me that people tend to equate carving to firm, icy or groomed conditions when in reality the principles of carving apply to most conditions if you want to ski in control. If you go by the “tail follows the path of the tip” & “bending the ski” definition, carving to me seems most common in round, linked powder turns ...

 

[geepers]

Platform angle is essential for grip.
They put platform angle center stage in the body of the video, great! but forgot to mention it again at the very end when they sum up. Darnit.

The vid was about more than platform angle and the statement at the end "To grip and manage turn shape we need to balance on our EDGES and control their ANGLES" summed it up well.

The full vid then goes on to discuss how to do that considering inclination and angulation. Plus many other things.

And they mentioned increase tipping angle to decrease turn radius - no need to park and ride.

Note that he doesn't mention anything about loading the tips. He does specifically mention being in the middle of the ski.

1. If you don't tip your ski up to a big enough angle, you will not achieve the platform angle.
2. The faster you go for any given turn, the more you have to tip the skis to achieve the platform angle.
3. The tighter you turn for any given speed, the more you have to tip the skis to achieve the platform angle.
4. You can tip the skis more than required to achieve the platform angle and hold the carve, but not less.
5. Most difficult to understand, for a given ski with a given side-cut radius, there is a limit to how fast you can go and still carve a clean turn of a given radius; as you tip the ski more on edge to achieve the platform angle, the self-steering aspect of the ski dials up a tighter turn. Eventually (because math - the cosine curve gets steeper) you reach the point where the turn dialed up increases the required tipping angle faster than you tipping the skis is closing the gap between the angle you have the skis tipped to and the angle required to achieve the platform angle at the speed you are carrying. That's why they make skis in longer radii for higher speeds.

Not sure these points add any clarity to the difference between platform angle and edge angle. And on point 5 is quite confusing.

Platform angle has nothing to do with speed nor edge angle. It is related to how we position our CoM, through angulation, "over" the ski. More specifically, on hard snow, the inside edge of the ski and it is predominantly the outside ski. We can have the necessary platform angle at 0 mph as a very useful vid from those fun Italians at JAM shows.


The reason "over" is in inverted comments is that it means over the ski in terms of the perceived gravity - the combined effect of gravity and centripetal force that the skier feels.

 

[geepers]

Carving is control, pure & simple.
It seems to me that people tend to equate carving to firm, icy or groomed conditions when in reality the principles of carving apply to most conditions if you want to ski in control. If you go by the “tail follows the path of the tip” & “bending the ski” definition, carving to me seems most common in round, linked powder turns ...
View attachment 104082

View attachment 104083

Nice tracks, nice skiing 4ster. But the evidence left in the snow points to some skidding of the skis - those aren't thin railroad tracks!

 

[4ster]

Nice tracks, nice skiing 4ster. But the evidence left in the snow points to some skidding of the skis - those aren't thin railroad tracks!

Nope, thin RR tracks are for firm or groomed conditions & beginners.
Same turns, same skis, different conditions...

Look deeper, pun intended .

 

[François Pugh]

The vid was about more than platform angle and the statement at the end "To grip and manage turn shape we need to balance on our EDGES and control their ANGLES" summed it up well.

The full vid then goes on to discuss how to do that considering inclination and angulation. Plus many other things.



Note that he doesn't mention anything about loading the tips. He does specifically mention being in the middle of the ski.



Not sure these points add any clarity to the difference between platform angle and edge angle. And on point 5 is quite confusing.

Platform angle has nothing to do with speed nor edge angle. It is related to how we position our CoM, through angulation, "over" the ski. More specifically, on hard snow, the inside edge of the ski and it is predominantly the outside ski. We can have the necessary platform angle at 0 mph as a very useful vid from those fun Italians at JAM shows.


The reason "over" is in inverted comments is that it means over the ski in terms of the perceived gravity - the combined effect of gravity and centripetal force that the skier feels.

Platform angle has nothing to do with speed nor edge angle, however the edge angle you need in order to achieve the needed platform angle (and grip not slip) certainly does.
Yes, as stated, point 5 is most complicated, but I typed it really slowly so you could follow along . It is as simple as possible, but as complicated as it needs to be to explain the situation. If you are going too fast for the side-cut radius of the ski and you don't tip enough, you will not reach the platform angle, but if you tip the ski more, instead of reaching the needed platform angle, you will only dial up a shorter turn and the tipping angle you need to be at to reach the 90 degree platform angle with the given forces for that shorter turn will be even further out of reach.

 

[slowrider]

 

[geepers]

Nope, thin RR tracks are for firm or groomed conditions & beginners.
Same turns, same skis, different conditions...

Look deeper, pun intended .

Ok, that one went over my head. And is still up there buzzing around... But I'm slow on the uptake.

Hard to know what's happening in deep, soft snow as we move so much out it out of the way with more than just the skis.

Nice groomer carving - is that leaning on the inside pole ingrained?

 

[Steve]

@4ster ive always loved your skiing! Thanks for sharing it so generously with us for years!

@slowrider that is a thing of beauty!

 

[geepers]

Platform angle has nothing to do with speed nor edge angle, however the edge angle you need in order to achieve the needed platform angle (and grip not slip) certainly does.
Yes, as stated, point 5 is most complicated, but I typed it really slowly so you could follow along . It is as simple as possible, but as complicated as it needs to be to explain the situation. If you are going too fast for the side-cut radius of the ski and you don't tip enough, you will not reach the platform angle, but if you tip the ski more, instead of reaching the needed platform angle, you will only dial up a shorter turn and the tipping angle you need to be at to reach the 90 degree platform angle with the given forces for that shorter turn will be even further out of reach.

Don't get your point with the focus on edge angle.

Platform angle has very little to do with the absolute edge angle. We angulate so some of our CoM gets shifted to the "outside" of the turn. This may have a small effect on the edge angle but the same amount of angulation that was required to make the ski grip at 20 degree inclination will not need to be increased to make the ski grip at 50 degrees inclination.

Edge angle is controlled by both inclination and angulation.



"If you are going too fast for the side-cut radius of the ski and you don't tip enough, you will not reach the platform angle". And yet we make rail road tracks (i.e. minimum slippage) at all manner of speeds on a wide variety of radius of the turns on skis with a wide variety of turn radii.

 

[4ster]

Ok, that one went over my head. And is still up there buzzing around... But I'm slow on the uptake.

Hard to know what's happening in deep, soft snow as we move so much out it out of the way with more than just the skis.

Nice groomer carving - is that leaning on the inside pole ingrained?

Well, a sure way to eat sh*t in deep, soft snow is to twist your feet while down in it.

I don’t feel like I am leaning on the inside pole but look at the drag like feelers or a cat’s whiskers . If ingrained means ”without conscious effort“ I would say it is ingrained. Unless I am skiing with no tipping, lean or angles l need to make a conscious effort not to have it drag.

 

[geepers]

Well, a sure way to eat sh*t in deep, soft snow is to twist your feet while down in it.

I don’t feel like I am leaning on the inside pole but look at the drag like feelers or a cat’s whiskers . If ingrained means ”without conscious effort“ I would say it is ingrained. Unless I am skiing with no tipping, lean or angles l need to make a conscious effort not to have it drag.
View attachment 104086

Looks like it's digging quite a trench in the vimeo.

Was channeling an indoor session we had with a course convener who was on the 2019 Interski team. He put up a vid of himself doing some pretty awesome skiing and invited us to critique it. didn't get much response from our group so he then replayed it saying the answer was obvious. Again no response. After a few times of this he eventually pointed out that on the 4th turn to the left he had leaned on his inside pole.

 

[François Pugh]

Maybe an example would help. Consider a 2g turn at 50 mph. Make it simpler by being on a horizontal surface. Gravity and turn forces will add up to give you a direction of about 26 degrees from the horizontal. To get a 90 degree platform angle, you have to tip those skis up to 64 degrees. If you tip a 13 m sl ski up to 64 degrees, it will try (unsuccessfully and scrape instead) to carve a 6 m turn. You cannot lay clean railroad tracks at 50 mph on SL skis.

 

[4ster]

Looks like it's digging quite a trench in the vimeo.

Was channeling an indoor session we had with a course convener who was on the 2019 Interski team. He put up a vid of himself doing some pretty awesome skiing and invited us to critique it. didn't get much response from our group so he then replayed it saying the answer was obvious. Again no response. After a few times of this he eventually pointed out that on the 4th turn to the left he had leaned on his inside pole.

No worries, better than falling over

l get that it can be a flaw but not a high priority for me in the heat of battle
I tend to drop my right arm more than my left but even keeping my left pole off the snow feels a bit contrived.

 

[geepers]

No worries, better than falling over

l get that it can be a flaw but not a high priority for me in the heat of battle
I tend to drop my right arm more than my left but even keeping my left pole off the snow feels a bit contrived.
View attachment 104092

Hey, it's all fine skiing. The CSIA L4s keep telling me there's always something. Damned hard to spot at times... pole touched the snow in 4th turn to the left is a good stand-by.