SPEEDBONE

[Alex Luxat]

triple-torsionbox sandwich+monocoque

my birthdaypresent to myself.
enjoy the pics.

<img src="http://www.slalomspot.com/wefunk/boards ... clear1.jpg" />



<img src="http://www.slalomspot.com/wefunk/boards ... clear2.jpg" />



<img src="http://www.slalomspot.com/wefunk/boards ... clear3.jpg" /> <img src="http://www.slalomspot.com/wefunk/boards ... bottom.jpg" /> <img src="http://www.slalomspot.com/wefunk/boards ... up_top.jpg" />



<img src="http://www.slalomspot.com/wefunk/boards ... p_side.jpg" />



<img src="http://www.slalomspot.com/wefunk/boards ... _truck.jpg" />



<img src="http://www.slalomspot.com/wefunk/boards ... rance1.jpg" />




<img src="http://www.slalomspot.com/wefunk/boards ... rance2.jpg" />

[Justin Pannulla]

Wow! That thing is a beast!

Very very very nice!

[Jamie Merrifield]

Did you have a chance to ride this beast yet? How do you like it?

[Alex Luxat]

Did you have a chance to ride this beast yet? How do you like it?

Hopefully I´ll ride it tomorrow. I´ll give my impressions then.
Now heading first for a bowl session.

[Luke Melo]

thats awesome! i saw the video of you explaining the design and materials used to make this board. very good info.

btw, the board is SEXY!

[Alex Luxat]

Thanks Luke!


The Speedbone and other Boncore decks are now raceproven (IGSA german, european and world championships, 5th place in the california race series (Bonelli Race Nov.), places 6 & 7 in the Kill Hill tour 2006).
Over 20 bonecore decks of different sizes are now out there and are raced successfully in Europe, Australia, the US and the Bahamas.

Comments on the decks rideability can be found as quotes on my site and on silverfishlongboarding.com

Here is a PM converstation and another (better) posting describing the idea beheind the construction and it´s properties (programmed flex and triple torsionbox):

Originally Posted by skatardude10
Seems to me like, the stiffer the board, the more response / predictability / grip you get from your wheels and trucks. It also seems like a tad bit of flex helps the grip... UNTILL your wheels break way. You said your board flexxes just a tad bit, then goes stiff. Let me take a guess...

When you say 'Programmed flex'... (just taking a stab at what you programmed it for) do you mean that you made it so it flexxes just enough to the point where the wheels break traction and at that point the board gets stiff so that you get the predictability / response aspect?

With programmed flex I mean that it really flexes but just for a few cm ... maybe 1 1/2" -- then the flex stops and the deck becomes harder ... it doesn´t bend or twist when hitting sharp cornes like thinner flexing decks do.
The UD carbon inforced stringer is recessed a few mm in the decks´ surface so under load first the glassfibres with the weaker tensile strength are used giving the deck the flex -- then the carbon kicks in gradually stopping the flex.

I think keeping/braking traction for drifts is mainly influenced by your choise of wheels.
BUT: The bonecore construction with it´s "programmed" flex absorbs some of the little shocks and vibration caused by road roughness and little bumps (like repaired pavement) making it more predictable and comfortable than a stonehard and thick wooddeck. With less vibration it´s easier to keep traction. It´s lower mass giving less outside momentum in corners also helps.
Of course it´s not magic and not a hoverboard. (but close )

In case you might worry it flexes/bends/twists when cornering ... here are some shots that show the difference:
The first three pics is wefunk teamrider Boris Schinke the third an unknown rider with an unknown flexing composite deck:






same corner shot from the inside (guy with brown shirt in the 2nd pic ^^) used for the ad in Naphte:






^^ That torsional twisting won´t happen in the Speedbone making it more predictable in corners.
If you hang in the impulse really gets to your trucks and isn´t lost in a twisting deck.

Hope that helped answering your question.

cheers
alex

(ps: May I post that (your Q, my A) on the speedboarding forum? Maybe it clears things up for others as well.)


this guy has a far better english technichal vocabulary than me and gets it on the point:

I'll let alex describe it better, but this is the basic idea of the triple torsion box, as I see it.

A torsion box is a hollow structure that is intended to resist torsion, or twisting forces. They are stiff, light, and resist twisting.

In the Wefunk triple torsion box decks, there are three torsion boxes, acting together. The center wood stringer, wrapped in UD carbon fiber, and the two sides of the foam core, which is capped in triaxial S-glass. Since there are three torsion boxes, each with slightly different properties due to their shape, cap material and core material, their properties 'blend'.

A flat piece of a single material has a simple relationship between force and deflection. You push harder, you get more deflection, proportional to the level of force. However, a torsion box, and particularly THREE boxes, each with different properties, gives a non-linear force/deflection rate. It might deflect easily at first, and then all of a sudden, stop responding to force. Thats the 'programmed flex' that he talks about. Early deflection from the triaxial foam cores (which are thicker, and 'engage' sooner), and then the flex slows down as the thinner (so it engages later) carbon wrapped stringer comes into play.

But while doing this, it has almost no torsional flex, because the three boxes side by side do a great job of resisting that sort of force.

Its a clever design. Making something as stiff as possible isn't that hard. But making it stiff torsionally, while still allowing a bit of flex along the long axis requires a clever design. Its stiff where it needs to be stiff, and flexes when it needs to flex.

Alex, feel free to correct me as necessary.

peace,
sam