PhysicsMans Sidecut Calculator - anybody got it still?

[tsk94]

Hi everyone,

Was wondering if someone might still have the excel sheet for this calculator lying around. Now that EpicSki is gone, I can't seem to find it anywhere else. Since a lot of people migrated here once Epic went down I thought they could be a chance someone on these forums has this excel sheet kicking around. If they do and wouldn't mind sharing it again that would be fantastic!

Thanks!

 

[François Pugh]

Here's how FIS does it.
http://member.fis-ski.com/skicalc.htm

Equations:
http://member.fis-ski.com/skicalc_info.htm

 

[François Pugh]

The uploaded file does not have an allowed extension.

PMSidecutRadCalc.xlsx

 

[Philpug]

With all the shapes, rocker designs, elongated tips, tapers, multiple sidecut designs, two and three elliptical radiuses...I am not sure there a a calculator that can take all of that in. I have gotten to the point where I start saying "Slalom like", "Mid teens", "Upper teens", "20-ish", "Figure 11's"...

 

[James]

You can try here. Let usvknow if you figure out how to use that thing.

https://archive.org/

 

[tsk94]

With all the shapes, rocker designs, elongated tips, tapers, multiple sidecut designs, two and three elliptical radiuses...I am not sure there a a calculator that can take all of that in. I have gotten to the point where I start saying "Slalom like", "Mid teens", "Upper teens", "20-ish", "Figure 11's"...

Those are good points, and I'm well aware it's not 'perfect' by any means. It's a good general calculator though to figure basic things like radius and surface area. Definitely not fully accurate but it was a fun tool to play around with sometimes. And of course, when I wanted to use it again after a few years I can't find it haha.

Also I've seen the FIS ones, but they miss some features the one Physics man made. If it's long gone that's totally fine, but thought I'd ask and see if anyone in the community had it kicking around.

 

[tsk94]

You can try here. Let usvknow if you figure out how to use that thing.

https://archive.org/

Found it! Thanks James for the suggestion, it didn't even cross my mind to try this.

For anyone that wants it as well: https://web.archive.org/web/2017051...681/physicsmans-ski-sidecut-radius-calculator

Should be able to download the excel file from that link.

Thanks everyone!

 

[crgildart]

Wasn't that done in Office 98 or 2000? XP might run it LOL..

 

[cantunamunch]

Wasn't that done in Office 98 or 2000? XP might run it LOL..

...or you can just use the given formula and write your own spreadsheet...

 

[Tricia]

This thread is an example of how some of the best parts of EpicSki will live on, without turning Pugski into Epic 2.0

 

[Noodler]

I 100% agree with Phil that current ski shapes make determining a single accurate sidecut radius number not possible. However, rather than worrying about the calculation providing an absolute value, what it can do is provide a relative value that is useful in comparisons across a group of skis. It won't tell the whole story as there is much more that goes into determining how quickly a ski can turn (including things like flex and rocker), but I still find it useful.

I don't like the FIS sidecut calculator as it makes assumptions about the effective edge length (EE) instead of actually using the effective edge length. It uses an 80% approximation for L1 and a 90% approximation for L2. If you actually have the effective edge length measured then that is L in their equation (L1 + L2). So the formula I use is:

Sidecut Radius = (EE*10)^2/(2000*(TIP+TAIL-2*WAIST))
* EE is multiplied by 10 to go from cm to mm (as mm is used in the calculations, but the result is in meters)

BTW - EE is the length of the edge material measured along the edge between the widest points at the tips and tails. It is NOT a chord length measurement. You must use a flexible tape to accurately measure this length.

 

[cantunamunch]

I


BTW - EE is the length of the edge material measured along the edge between the widest points at the tips and tails. It is NOT a chord length measurement. You must use a flexible tape to accurately measure this length.

So you're not using the Intersecting Chords theorem to derive your formula? Are you making an argument by area?

 

[Philpug]

Wasn't that done in Office 98 or 2000? XP might run it LOL..

It might have been done on Lotus123

 

[Tom K.]

I find two things on this topic (which I maybe pay too much attention to):

1. There is close to zero correlation in stated turn radius across brands, if you go by how they feel on the slope. Kind of like stated boot stiffness.

2. I can get a pretty good idea how that aspect of a ski is going to feel by looking at the tip/waist/tail deltas, the relative stiffness of the ski, and amount of tip/tail rocker and taper.

As an example, Enforcer 100s don't have huge deltas. But they aren't that stiff, either, and end up carving a mean arc on soft groomers. In contrast, I had an old pair of Line Influence 115s that looked turny on paper, but were pretty darn STIFF, so didn't feel that way on the slope.

 

[Noodler]

So you're not using the Intersecting Chords theorem to derive your formula? Are you making an argument by area?

I've never considered the actual theorem that is the basis for this calculation. I am only basing the formula I use on the work shown in the FIS Ski sidecut calculator. Physics man's formula arrives at the same values as when you use EE in the FIS formula. However, P'man's formula looks quite different, while arriving at the same results.

 

[cantunamunch]

FIS do use ICT - they make an educated guess as to where the waist is - which is why chord length is correct to use in theirs. I would have to re-read Lind & Sanders to see how they get around the waist position problem, but they also use chord as effective edge (according to Pman's post since I don't remember).

 

[crgildart]

I have it, sent to staff via PM. As mentioned, it's only good for full cambered skis, sketchy to worthless for rockered or reverse sidecuts.

 

[François Pugh]

Should apply to rocker, once you get it leaned over to the point that the widest points make contact.

 

[crgildart]

I have it, sent to staff via PM. As mentioned, it's only good for full cambered skis, sketchy to worthless for rockered or reverse sidecuts.

Nevermindl see below.

 

[LiquidFeet]

Are people having difficulty accessing PhysicsMan's calculator? I had no problem. I went here (noted above in @tsk94's post):
https://web.archive.org/web/2017051...681/physicsmans-ski-sidecut-radius-calculator
Click on the link to the excel file in the first post. It works just fine.