Radius question - Jacques, Patrice, anyone.

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rcrobar
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Radius question - Jacques, Patrice, anyone.

Post by rcrobar » Sunday 24 March 2002, 21:01

Jacques, Patrice, anyone

What type of board specifications (overall length, contact length, etc.) would you recommend to “Extreme Carve” on a board with a smaller (9.5m) side cut radius?

PS - The local hills in my area (Northern BC) are very, very narrow and have trees to either side; rarely do the rums open up. Thus the desire for a tighter turning “Extreme Carving” board.

2. Did Wild Duck Snowboards ever build an “Extreme Carving” board with a smaller side cut radius? (Smaller than the13m listed in the Specifications) How did it perform?

Thanks for your time.

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Re: Radius question - Jacques, Patrice, anyone.

Post by McFussel » Monday 25 March 2002, 12:24

Hi there...

check www.virus-snowboards.de for a good overview over Carving Boards. These guys are a little arrogant, but they build definitelly the best boards!!
The Nightmare does really narrow turns, has good icegrip and is nice to carve...

Other good boards for Carving: Check THIAS Sqwal or the TRANS Boards...

Carve on ;o)


rcrobar wrote:Jacques, Patrice, anyone

What type of board specifications (overall length, contact length, etc.) would you recommend to ?Extreme Carve? on a board with a smaller (9.5m) side cut radius?

PS - The local hills in my area (Northern BC) are very, very narrow and have trees to either side; rarely do the rums open up. Thus the desire for a tighter turning ?Extreme Carving? board.

2. Did Wild Duck Snowboards ever build an ?Extreme Carving? board with a smaller side cut radius? (Smaller than the13m listed in the Specifications) How did it perform?

Thanks for your time.
:D :D :D
Don´t ride the chicken line!

http://www.carving-masters.de
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well not agreed>>

Post by nils » Monday 25 March 2002, 12:48

Mc F!
If you read carefully the equipment section of the site, you saw the reason why we should avoid narrow boards for extremecarving... The main reason beeing the angles that are resulting from the small waists> too much angle means locking the legs on the boards, not allowing the knees and weight to move sideways on the board...This is why a good waist seems around 21-22cm....Virus's 16cm and the skwal, which are good carving tools, will not allow to lay down so flat on the snow (and recover)> high angles means your hips and shoulder( skwal) will touch snow sideways instead of alongside...
I have looked carefully for pics of skwalers in extreme positions, and they are still far away compare to what u see here...

Cheers!
Nils

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Post by rilliet » Tuesday 26 March 2002, 12:10

Hi rcrobar,

One guy (hi Peter Vu!) mailed me already about the question of big radius in exteme carving. There the answer I gave.

You reason with normal turns.
The question is:"Which radius will my board make during a laid turn, I mean, when it lies nearly vertical on the snow?"
When Patrice and me look to our tracks, me can see that its radius is about 4 meters. But the shape radius of our boards is 13 meters.
If the shape radius decreases, the turn radius will decrease too.
Imagine now That your snowboard has such a radius sothat when you
lay down a turn, its radius is the same as your own size (ie 1.70 m).
it that case, your board will slide with a certain speed but your head
will have no speed at all! You will turn like compasses, that is really not fun at all!...
With a snowboard that has 8 meters of radius (wery common), the laid turns become so shorts, that the upper boby of the rider has nearly no speed anymore!

One of the most fabulous feelings available in extreme carving is the speed sensation with the eyes very close to the snow. To get this speed, the radius of the turn must be much larger than the size of the rider (a bit more than the double in our case), and so the radius of the board must be large enough...
We tried several radiuses (8, 9, 10, 11, 12, 13, 14 and even 26 meters) and 13 was the best compromise for us.

Carve down

Jacques Rilliet

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Re: well not agreed>>

Post by McFussel » Tuesday 26 March 2002, 12:59

Hmmm...maybe you´re right - but it works fine for me ;o)

Right now I´m riding 13 and something about 20 degrees in a 14cm narrow Black death - good on ice and good slope.

If you turn in your upper Body carefully, you can lay down like this - but you are right - it is not nearlly the same style, it´s a little different. But for me it´s pure fun ;o)

nils wrote:Mc F!
If you read carefully the equipment section of the site, you saw the reason why we should avoid narrow boards for extremecarving... The main reason beeing the angles that are resulting from the small waists> too much angle means locking the legs on the boards, not allowing the knees and weight to move sideways on the board...This is why a good waist seems around 21-22cm....Virus's 16cm and the skwal, which are good carving tools, will not allow to lay down so flat on the snow (and recover)> high angles means your hips and shoulder( skwal) will touch snow sideways instead of alongside...
I have looked carefully for pics of skwalers in extreme positions, and they are still far away compare to what u see here...

Cheers!
Nils
Don´t ride the chicken line!

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Thanks for the help

Post by rcrobar » Tuesday 26 March 2002, 20:27

Thanks for the explainations everyone, it has helped a great deal.
Rob

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snowboard math

Post by Guest » Friday 5 April 2002, 9:52

Have a look at http://www.natew.com/frames.cgi/software/snow/html.Main

Pick the 'forward engineering' link and you'll get a calculator made with Javascript. This is something I created to help get a mathematical perspective on questions like this one. Don't expect it to give you the one true correct answer for your every problem, but it can provide food for thought. :)

Anyhow, this calculator suggests that if you're getting 4m radius turns from a board with a 13m sidecut, this suggests that your edge angle is about 72 degrees. To get 4m radius turns from a board with a 9.5m sidecut, you would use a 65 degree edge angle. Or, looking at it another way, a 72 degree edge angle and a 9.5m sidecut would give you 3m carve radius.

Subjectively speaking, I have an easier time carving with a 13m sidecut than with 10m. It's the tight turns that make the 10m board more challenging. It turns so much tighter, it's almost violent. I lean in, and bang, it has turned around. Also, with my 10m board I sometimes find myself going so fast it will not carve at all, and I don't like that feeling. I have not experienced that yet with the 13m board.

Sometimes I think I should go to 11.5m on my next board. That should let me carve in less space (on narrower runs) and at slightly lower speeds than with my 13m board, but it won't turn quite so tight as my 10m board. Mostly it's the speed - at 13m I feel like I need to be going pretty fast to lean way in without simply falling to the inside. But I probably will not get another board until next season or the year after, so I have a long time to think about it, or to get more comfortable with riding faster. :)

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Post by rcrobar » Saturday 6 April 2002, 0:02

Too Cool .... Thanks .... I love the program you created.

Is there a way to calculate (a general idea) the turn a given radius will make when the riders STANCE SET BACK is factored in.

I'm always amazed at how the same radius can draw a different line on the hill, depending on the degree of setback.

Thanks again

Rob

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Post by NateW » Saturday 6 April 2002, 0:10

That was me posting above, I just forgot to log in... I'm not aware of a relationship between setback and carve radius. The calculator computes carve radius as a function of edge angle and sidecut radius, nothing else. If someone has a formula that relates carve radius and setback for a given sidecut radius, I'd like to see it. I have no idea how that relationship would work.

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Post by rilliet » Sunday 7 April 2002, 16:45

What does "stance set back" mean?

Jacques

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Post by Guest » Sunday 7 April 2002, 19:16

Back of center ... the stance centered on the effective edge.

IE-Slalom 2.5 cm back, GS - 4.5 cm back, E-carve - centered.

This weekend I continued testing your recommended settings. I used a 171 Burton prime with a 20cm waist and a 13m sidecut.

Normally I ride this board with the stance set 5cm back of center, 57F, 54B, 6 degrees lift back and 3 degrees front. I run out of room when laying a turn way over on a narrow run.

The same board on the same run with your recommended E-carve settings (moved forward on the board or centered) is able to complete the turns easily, while only being moderately laid over.

Are other testers getting the same resutls?
Rob

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set-back

Post by NateW » Wednesday 10 April 2002, 8:07

If the board is built with no taper - same width at the nose and tail - then a line drawn from the center of each sidecut arc will intersect the middle of the effective edge. If the board is built with taper - a wider nose and narrower tail - then the center of the sidecut arc is moved back a little bit.

I am not sure how important this parameter is, but I was curious about it so I put it in the calculator. My guess is that during a carve the center of effective edge is more important and the taper is irrelevant. When switching from edge to edge though, the taper is relevant, and the setback probably also matters. So, it's probably more important to slalom riders than carvers.

This reminds me, are your boards designed with any taper? I did not notice this parameter in your 'settings' page.

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Post by rilliet » Wednesday 10 April 2002, 14:42

Hi Nate,

No taper on our boards and no set back.

If you put taper without setback, then the edge switching leads to edge skidding. So it's necessary to have some set back. But set back makes the tail edge shorter than the nose edge. This makes the tail edge too weak toward the nose one and so the board becomes unbalanced on the edge (the tail skids). This is especialy sensitive on backside edge.

Having taper gives safety against front side loop in hard carving.
But the special construction we use makes the board totaly safe against these "nose diving". :wink:

Jacques

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Post by rcrobar » Wednesday 10 April 2002, 22:15

Hi Nate

The board I was using for my test did have a taper.
I measured the tip and tail of the 171 Prime, it appears that the taper is 2mm.

Rob

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Post by rcrobar » Thursday 11 April 2002, 1:47

Hi again Nate

The other board that I was using for the test was a Prior 4WD. It also seems to have a few mm of taper. For got to mention this in the last post.
The Prior web site says it has 4, but the specs on my board seem to be different.

IE-The web site says that the 174 4x4 has a 10m radius, while mine has a 10.5m radius.

Rob

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