calculation on turning radius

[thebigeast]

anyone here smart enough to tell me how to get a skis turning radius from the skis dimensions?

[Sinecure]

I'm pretty sure you meant Sidecut Radius, not turning radius.

Try this page for calculating. Use the "reverse engineering" link midway down the page. Its pretty cool.

http://www.natew.com/frame_main.cgi/...snow/html.Main

If the ski/board is tapered, just average the tip/tail lengths.

For a more simple calculation, you might try this formula:

R = l2/8d + d/2

R = sidecut radius
l = running length
d = sidecut depth

you can omit the d/2 term if you want because it is pretty much insignificant.

[davep]

I usually just go outside and draw gigantic-assed circles on the ground till i find one that fits.

[doublediamond223]

This one works a little better.

http://www.websurd.com/epic2004/PMSidecutRadCalc.xls

Put the published length of your boards in the obvious spot, then input the tip, waist, and tail into the obvious fields. The rest is automatically calculated

(Credit goes to PhysicsMan from epic)

[HitMe]

Why approximate when you can get the real thing:

Just denote tail width with tail, waist width with w, tip width with tip, tail to tip with tt and tail to waist with tw, then the sidecut radius is given by:

radius=1/1000*sqrt(-((((tail-w)/2)^2*((tail-w)/2*tt-(tip-w)/2*tw)-(tw^2)*((tail-w)/2*tt)+ (tw^2)*((tail-w)/2*tw))/(-(tip-w)/2*tw-(tail-w)/2*tt+(tail-w)/2*tw)-(((tw^2)*tt -(((tip-w)/2)^2+tt^2)*tw -(((tail-w)/2)^2)*tt +((tail-w)/2)^2*tw)/(2*(-(tip-w)/2*tw-(tail-w)/2*tt+(tail-w)/2*tw)))*(((tw^2)*tt -(((tip-w)/2)^2+tt^2)*tw -(((tail-w)/2)^2)*tt +((tail-w)/2)^2*tw)/(2*(-(tip-w)/2*tw-(tail-w)/2*tt+(tail-w)/2*tw)))-((tw^2*(tip-w)/2 -((tail-w)/2)^2*(tip-w)/2 +(((tip-w)/2)^2+tt^2)*(tail-w)/2-(tw^2)*(tail-w)/2)/(2*(-(tip-w)/2*tw-(tail-w)/2*tt+(tail-w)/2*tw)))*((tw^2*(tip-w)/2 -((tail-w)/2)^2*(tip-w)/2 +(((tip-w)/2)^2+tt^2)*(tail-w)/2-(tw^2)*(tail-w)/2)/(2*(-(tip-w)/2*tw-(tail-w)/2*tt+(tail-w)/2*tw)))))


Looks awkward? Try the javascript version at: http://members.fortunecity.com/hhitme/skiradius.html

In fact, even though this formula calculates the radius of the circle uniquely defined by three points it is still an approximation of sidecut radius. Most skis actually don't have a circular sidecut and hence "radius" is not even well defined.

Personally I prefer to go skiing...