:: View topic - First Ski Design

Well I've been reading around for months now and I'm ready to build.

I think I have most of the bases cover for the construction process. Now for some designing!

This all started with there being three awesome days on my hill where we had 3+ft of fresh and only the groomers were skiable.

As it's refered to by some as the "wet coast", the west coast of Canada, particularly Vancouver Island can have a ton of snow that is too heavy to ski till it consolodates somewhat. Even a friend on K2 pon2oons was keeping pretty straight lines but at least he was out there with a few guys with big snowboards.

I want to build a ski for those days that might still be able to make back to the lift on the groomers without too much trouble

I ski G3 El Hombres right now and I love them so the first design is based vaguely on them....just way bigger with rocker tips..

I'm planning a bamboo and yew core and yew sidewalls

So please give me any thoughts and or criticism

JT

[/img]http://imageshack.us/f/577/bigbambu.jpg/

Ooops..I think I have the photo posting figured out now.

I'm not a skier, and not a expert

I think tail length is not a detail, for a ski/snow that need to avoid sinking. IMO, yours is a bit too short

the problem is I'm not sure of the right design, so I prefer not giving any advice that can be wrong

that ski looks dope for a super fatty.

the tough part will be making the flex right on such a fat ski.

Yea, that's super fat. So for the wet snow is the goal to be able to stay on top of it, bust through crud, or both? I've found a ski that is torsion-ally firm is good for busting through crud.

For what its worth, my powder skis are 155/130/145 and I love them. But they're only 160cm length (I'm short), and totally reverse camber so they're super squirrly on the groomers. In powder they are effortless though, I love them.

Thanks for the feeback,

MM...do you have any tips for figuring out the flex? I was thinking of carrying the taper of the core into the rocker tip just past the front contact point also using a strip of carbon under the core. any thoughts here?

SD....my thoughts are to stay on top. I was thinking of using, I think elan's idea, of ripping the bamboo cores down the middle and using a quick fixture to plane the side-cut out of the middle, then re-laminate with a yew stringer up the middle. Has anyone else tried this? I thought that this might help with a ski this wide. what do you do to increase torsional strength?

Twizz..... I've played with the length alot. I skied some S7 @ 183 (i think) and I liked the idea of them but I dont do a lot of skiing backward (on purpose at least) so I did away with most of the rocker in the tail. My El Hombre's are 177 and I think they could be a bit bigger....with 35cm of rocker up front these will actually be a bit shorter than the running length of the G3's.....but way wider....but this all just a guess... any thoughts?

Your design looks good, I'd taper the tail a little, less square, tough to bend edges like that and rounder might release easier in the end of the turn, more smearability.

What glass are you using and how thick is your core profile?

For a wet crud buster you'll want it fairly stiff in the tip as well as stiff torsionally. A soft tip will deflect to much in wet or crusty snow making things hooky.

My personal idea would be 2.3-12-2.3 for your core with 19 or 22 oz glass. The only difference between 19 and 22 oz vectorply glass is the weight of the longitudinal fibers. The 45s are the same wt.

You could add some carbon tow on an angle between the contact points

Hey Vinman, thanks for the info

I'll change the tails and send another jpg to see what you think. I'm using 19oz triax hence the yew and carbon.

Sorry for the ignorance, can you expalin the word tow in this context? Ive seen it before here and I've got an idea of what it is. Any photos by chance?

I was thinking 12mm for the coe down to 2 at the ends only due to the tip spacer material. Do you sand the cores from 2.3mm where they meet to blend the transition?

Carbon tow is just strands of carbon, non-woven. I'm not sure I use this term right myself.

I have a carbon remnant woven with basalt. I just pull individual bundles out of the woven fabric and put them in the layup. I use tow for this type of bundle of carbon strand.

Yes I hand sand my tip spacer wood area to match my plastic.

Vin,

I've done some looking at suppliers like CST and I think youre right on with the description of "tow". thanks

I have an idea of how i would orient the strands but I have no idea of how much to add...I dont want 2x4's and I think i would err on the stiff side. Is there a rule you use?

Below is the re-design of the tail section as you suggested. however my question on this is...

I don't see the need for rocker in the tail section so I was tring to emulate the El Hombre...where the tail turns up just for 4cm or so and has a square (with a notch for skins) tail and the edgse stop there...no wrap on the tail. Since the tail ends abruptly there is nothing behind to hinder turns. Does the added rocker in the tail improve performance/floatation and if so how does it differ from the square idea? If I could have figured out how to make the first design square I would have only due to my love of the El Hombres...frieght trains that can turn!

Thanks again for the feedback

In that case you are probably right, really no difference. I personally like a rounded tail, since I usually put rocker in the tail and I do full edge wraps.

As for the carbon, I'm still experimenting with it myself so I don't know what to tell you. So far I have it in a ski with a 2.2-12.2.2 core with 19 oz glass and 6 stands on both sides of the core. This ski came out pretty stiff and should be a beast on firm snow and I may have overdone the carbon.

I've also done a ski with a 11.8 core with 4 strands top and bottom. This once came out stiff but not too stiff, I think this one is nearly perfect in the flex for my liking.

The third pair has an 11.4 core and 4 strands top and bottom. This one was noticeably softer than the other two.

What I don't have to compare against are any cores of the same profiles with only the 19 oz glass. I think most of my variance in flex is related to the waist thickness and not so much the carbon.

My guess is that yes the carbon adds some stiffness but how much I can not say.

So here's the idea I had for the core.

As some have stated the wider the ski the more torsional rigidity is required to help it handle on firmer snow.

I always keep thinking of the video I mentioned further back in the string of Elan (I think) ripping the cores down the middle. They then put both halves on edge in a fixture and ran it through a planer creating a bow in the middle of the core.Then they clamped the two halve together to create the side cut.

I always thought that was a better idea than cutting through the vertical "grain" of the lamination to create sidecut.

The center of the core will be yellow cedar and doug fir. The lamination that follows the sidecut will be bamboo. The sidewalls are green.

Any thoughts on benefits or????

I think you'll get what you're looking for. How many stringers per ski? The glue up might be a PITA.

SD,

Sorry for the ignorance but if by stringers you mean how many pieces in the lamination of bamboo it will be 6. they are roughly 5/16" each.

I purchased some dimensional bamboo lumber and will be ripping and jointing it to the thickness I need. I may have to rip two pieces for each side to get them to bend enough to glue up.

I was thinking of a quick form to help with this.

This is more work in an already ambitious project so I'm trying to get an idea whether it's worth all the extra work?