Hi guys,
I'm actually working on a rockered design and found this super interesting thread, instead of starting a new one I'll just add my thoughts/questions here !
Last summer I designed a rockered ski, I actually never skied that kind of sticks but I found the idea very interesting to I wanted to give it a try. So I designed it, had the templates and tip&tail molds machined with my other shapes and left it sitting on a shelve 'till a couple weeks ago.
On new years day I finally pressed a rockered ski and although it looks really nice from an artistic point of view I have serious doubts about the ride. The rocker is pretty long but not that high (400x20mm front, 300x15mm back), there is no real tip or tail, regular camber underfoot, regular sidecut going from tip to tail... I'll post pictures later.
If I sit and look at my work I can tell I did think a lot about the look of the ski but not that much about the theory behind it... So I'll give them a try of course but I'm already thinking of an improved design, carefully thought !
The rockered ski I want to make is gonna be used mainly for eastern "backcountry" skiing, meaning it has to be good on powder and trees but still be manageable on packed snow or ice (which will make it a descent ski for resort also).
Here is a small draft of my latest thoughts, dimensions in red are what I plan to do (roughly) but for this thread I'm more interested in the concept behind a rockered ski than this exact shape/dimensions.
As you can see, although there is a rockered tail it's still a directional ski (not pure twin tip), the front rocker will be slightly longer and higher than the tail rocker, same thing for the actual tip and tail.
Some questions : on a rockered ski, what's the running length ? Is it still the length between the contact points or do we also consider the tip & tail rockers ?
As I said in an other thread, when I'm designing a ski I want the binding mounting point to match the narrowest point of the ski, which idealy will be 55% of the RL... I don't know if this is still a good statement with rocker ?
Is it correct to have the widest points of the skis to match the contact points ?
On the skis I design for me (I work a lot with parametric curves and arcs) I took RL1 (Running length = between contact points only) and RL2 (running length = regular camber + tip and tail rocker), I took the 55% point on each one and made them match. This gave me the mounting point and the narrowest point.
Where I'm now having a hard time is when I work on the top view (sidecut), I want my widest points to be @ the contact points BUT the running length (RL1) is pretty short, with the dimensions I want (130-110-120) it gives some pretty tight radius, especially on the front (less than 10m). In the back though I can get a 20ish radius which is fine IMO. Do you think instaed if starting form the dimensions I want (130-110-120) I should start with a radius (let's say 25m or 23m front/26m back) and the width on contact point will be what they'll be ?
That's gonna be it for now I have to go back to work... Thanks for reading and hopefully contributing.
Let me know if you see some major mistake on just what you think.