Designing a Ski...

[ed]

Hey, this is my first post on here!

I have been really interested in making some skis for ages now. I'm pretty experienced in laying up composites and laminating wood so I think I'll be able to make a good go at it.

My problem is I don't know where to start when it comes to designing a ski. There are a lot of factors that I just take for granted and never really think about when it comes to the geometry and the flex patterns of the ski I ride on. Currently I have a set of Armada AR6's which I think are a fantastic ski to use, so long as you're in the park or out on the soft stuff, but when you get them onto something groomed or hardpack they are a struggle to say the least.

Ideally what I want to design is an all mountain twin tip that's like the AR6, but easier to use, but seeing as I don't know what design factors affect the characteristics of the skis when you get them on the slope I don't know what to incorperate into my designs.

I'm going to design the ski's on my computer using Solidworks, I could even test the flex patterns and perform stress analisys in the FEA software that's integrated in there called COSMOSworks, as I use this software daily as i'm a designer. But I don't want to get ahead of myself as I need to probably have a few goes at getting the laying up process correct first!

Anyway, any pointers on ski design would be gladly appriciated

[collin]

One place to start would be determining what kind of flex you'd like.

Do a search for a post by endre (I think) where he posted a nice plot of production ski flexes.

And do a search for a post by bambi where he posted an excel file that computes the flex for core shape and glass weight.

[rockaukum]

My first ski was a tracing of the factory skis I was on. It would be my opinion to stick to the KISS principle (Keep It Simple Stupid) for your first try and note the characteristics then tweak it and compare the changes.
NOthing compares to skis you build yourself!
rockaukum

[plywood]

stick to the KISS principle (Keep It Simple Stupid)

i`d second that

don`t waste your time with cad, fem and all this stuff - it may be fun to play with, but i really doubt if it helps you anything. in the end it is still "try and error".
so just stick to a factory ski, as rockaukum said. or if you want it a bit more advanced: take the radius from a factory ski and change the dimensions. or if you want a fatter ski for example just add this 1cm or whatever to the dimensions of the ski you already have. that`s what i did: i wanted a fatter ski, overtook the dimensions of tip and tail from the "whites"(see kams gallery on the main page) and then i copied the radius of the ski i rode...and that`s it.
and the stuff with the core thickness and how much fibres...this is a matter of luck and experience no, seriously: go through the gallery, look what they did there, and copy it. it will work for your first pair. (if i remember right the kams used 2sheets of 220oz triaxial fibreglass on cores with 11mm in the middle and this worked best).

but in the end you really have to build a pair and then see how they are. there are so many factors you can influence and change that there are endless possabilities. and everyone prefers a different type of ski...

[ed]

A copy of a factory ski would be a good place to start actually. They probably wont come out right first time!

I was going to CAD stuff up purely because I can CNC the cores and the base out which seems to be an easier way to do things rather than making a core profiler and cutting the base by hand. I would also be able to CNC moulds out quite quickly too.

[Greg]

If you want to see a good example of going too far on the first pair of skis, check out the Bremallows in the ski gallery. That was my first pair of skis, and when I built them, this forum was quite small. I think anyone starting ski building can learn a lot from the countless mistakes I made while building those because there were very few things that worked out correctly. Then after 5 days of skiing, the completely blew up.

If you can CNC stuff out, then CAD would be the way to go. It might not save too much time, but it could really help to improve the consistency and overall quality of your skis. However, seconding the notes above, a lot of guys (in my opinion) spend too much time with the design and computer stuff when they could be actually building skis and improving their skills. In the end though, ski building is a craft, and a good ski requires the right materials, and the right process. And, I think a lot of the guys here will agree with me that most problems with skis are caused by the process portion.

Good luck though, and I can't wait to see how they turn out. I really envy your access to CNC machines, because I can't cut a straight line on a bandsaw to save my life, and always end up having to do a lot of hand planing to get things lined up.