A question for board builders.

[mr_roboteye]

I'll talk about skis but trust me this relates to boards too.

I have an extensive collection of skis. I have also tried a ridiculous array of them at demo days, borrowing etc. I have two pairs in my collection that from a carving / performance standpoint standout by leaps and bounds. They share a unique charachteristic. Their cores are curved on the short axis forward of the binding mounting point, one pronounced, one subtly. I'm pretty sure that this is a technique to add torsional stiffness without adding significant weight. Both these skis are loaded with metal.

It really works. I have tried many many skis ($1200 head race stock, stockli, atomic) none of them have the performance of these two skis. I don't think it's a coincidence that my two favorite skis have a similar profile.

My question is: Have any of you board builders considered putting a profile like this on the forward portion of the board to further beef up torsional rigidity? If you have tried this before, did it work or not?

The only board that I've seen that was anything like this was a nitro model that was called a CAM. The topsheet had irregular bumps in it that were computer designed.

just curious,

Dave R.

[dingbat]

Yes, but I'm only on my second board and haven't goten around to trying it yet. I think that it may be impractical for snowboard widths though. I'll probably still try it a couple boards down the road. If nothing else it'll look kinda cool. ;)

[MUD]

Rad air does/did it on the Reto Lamm....

There are quite a few "shaped" cores out there. Have you seen the top sheet of a Virus? Palmer had the channel......

Do I understand what you mean? Or are you just talking simple curved tops?

[KingCrimson]

This reminds me a little demonstration Boris came up with showing why caps are stiffer.

Take a piece of paper and on the long ends, fold about 1/2" towards the center, making the basic structure of a cap ski or board without the core or base. Then put a nick in the side to show why cap is delicate..

I'd ASSume the core profile, and consequently the shape of the glass layup has the same effect, while maintaining the benefits of a sammich board.

The question is...how hard is it to bend the metal around that shape?

[KingCrimson]

I thought that was what those little stix were for?

Tinkman and others are certainly aware of this?

:)

I think the ways that board builders try to make boards more torsionally stiff are the coolest technological aspects of the sport. We were talking about this on Sunday at our little Expression Session when trying to figure out the age on an F2 Silber. They stopped making the Conshox in 05, and put it "under the skin" on Silbers in 05 IIRC, evident in this picture

http://www.freeride.ch/Freeride-Home/board_top/Snowboard/Bilder____/Board/f2_silberpfeil_07.jpg

I'm curious about the structure underneath Dave's skis, in particular what the metal is shaped like.

Bryan and the rest of the Oregon crew- What do Tinkies have when you call a Tinky a titanal board? Does the butterfly have metal as well?

[mr_roboteye]

Rad air does/did it on the Reto Lamm....

There are quite a few "shaped" cores out there. Have you seen the top sheet of a Virus? Palmer had the channel......

Do I understand what you mean? Or are you just talking simple curved tops?

I haven't ever seen a rad air (any model) in the flesh, but I'd like to.

I have seen Boris' virus, but I didn't take any note of the core profile. If virus does this, it could have something to do with why they are so highly regarded for their ride quality?

I am talking about a simple curved top. It does make sense if you think about it. It would be harder to twist something with a curve in it's profile than something that's basically shaped like a hershey's chocolate bar (rectangular).

I'll see if I can make an interesting drawing. I think it waould be a telling experiment to make a board with a profile like this, only problem is you would probably need a CNC mill to mill the core in a consistent fashion.

later,

Dave R.

[mr_roboteye]

I think the ways that board builders try to make boards more torsionally stiff are the coolest technological aspects of the sport.

I'm curious about the structure underneath Dave's skis, in particular what the metal is shaped like.

I don't know for sure, but I'm pretty sure it hugs the core.

later,

Dave R.

[BlueB]

Sure you've seen my Tanker 192 at WES 2007. That's how you found me in the crowded lift line - board sticking up way above anything else ;)

I had a Reto Lamm for a very short time, it does have the profiled top, just as my current softie favorite, Elan Vertigo. Elan has built in dumping system and, rummor has it, titanal too. Quite a few boards have profiled tops, most pronounced being Oxygen APX, directly inspired by Atomic Metron Skis. Many hi-tech, but non metal Virus have it too. My Vampire, as majority of titanal boards, is flat top.

It's kinda no-brainer - 3d structure is always stronger then flat one and normally has better torsional properties. However, it has many trade offs, like more complex engineering, difficult tooling, hard to customize, adhesion problems and problems associated with metal layers whan you want to bend them in 2 planes.

Note: All these mentioned boards have some kind of "fork" or "butterfly" 3d shapes, I havn't seen one with a simple single lobe like on your skis. It probably wouldn't work that well on wide shape. Majority of the modern skis have gone dual lobes, anyhow.