The Hoff WW140 - wave twintip

[rynhardt]

I've been inspired by Plummet and KerryBarra's work and am planning to build a wave-oriented twin tip, but with some of my own perversions thrown in.

Size: 140cm x 44cm - this will be a general purpose board and I prefer it slightly wider as I have big feet.
Rockerline: 4cm Hydrodynamic (NACA 0012) - same one I used on my transparent board, efficient with good pop.
Bottom profile: flat, i.e. no concave - stiffness will be determined by layup schedule and thickness.
Core: 10mm corecell - light, easy to work with
Rails: 5mm thick ABS - should bond well with epoxy
Stringer : 10mm ABS - I'm solvent welding 2 layers of 5mm ABS to get to 10mm
Inserts: Kerry's stainless M6 inserts - wakeboard style, 3 sets, spaced 6" apart, ready to mount bindings
Graphics: Printed graphics applied a'la Kerry
Construction method: Resin infusion a'la Kerry
Layup: Graphics, Alutex 45/-45, Biax Carbon 300gsm 0/90, Core, Biax Carbon 300gsm 0/90, Alutex 45/-45, Graphics

I'll post more pics as the build progresses..

[plummet]

Some thoughts for you.

I'd mix drop back to 200gm carbon, Mix the weave orientation
to 45 alutex
90/0 carbon
core
45 carbon
90/0 alutex.

However the most efficient use of the carbon is on the outside layer. That's where it will provide greatest stiffness.

Ellipse shapes give away surface area where its needed. At the tips.
Your 140x44 as a similar surface area to a 131x41 square tipped TT. It might be a power hungry mite. Particularly with no concave. Concave flattens the water line and makes the board more efficient. EG mako Huge rocker, huge concave. Crank some concave if you can.

Consider a rounded rail.
40mm rocker will be sweet on small sub head high stuff. If you want to blaze headhigh plus then more rocker might be needed.

[rynhardt]

However the most efficient use of the carbon is on the outside layer. That's where it will provide greatest stiffness.

Yeah, but the only reason I want the alutex is as a cosmetic layer for the graphics, so it has to go on the outside. Since I'm going to be using it anyway I can just as well use it for torsion control.

Ellipse shapes give away surface area where its needed. At the tips.
Your 140x44 as a similar surface area to a 131x41 square tipped TT.

Thanks for this - a good idea. I've bumped up the size to 146x46 (8% larger)

Crank some concave if you can.
Consider a rounded rail.

I'm cutting material for two identical boards, just in case I stuff up the first one. The first one is going to be flat, but if it's a good build then the second one is going to have concave.
I want to find out for myself just how much difference it will make..
And I'll start out both with square rails, and then sand it round and see if I can notice a difference.

Anyway, here's the rocker table complete. Got my ABS today and am sending it for cutting tomorrow.

[Laughingman]

Hi Rynhardt
Just wondering, are you having your abs cnc cut? What about the corecell?

[plummet]

Another thought for you. fibers at 90 are almost useless for adding strength to a board. 45 good for torsion. 0 good for flex control. 90 hold the board together in the case of using only foam core but provide little value after that.

Maybe ditch one layer of mat carbon in favour of uni. Get the fibres going in the direction you want strength.

So maybe something like this

Top
alutex 0/90
200gm carbon mat 45
core
200gm carbon uni 0
alutex 45


Also check out nomad kiteboards layup. They role with stringers of carbon uni at various angles to obtain the strength/flex they want.

http://www.nomadkiteboarding.com/index-aboutus.html

[downunder]

That is a lot of work and materials spent to use Kerry's inserts. No offence K. (i don't remember seeing them, not sure how good they are), but get the professional industry standards inserts, M6, here:
http://boardbuilders-forum.1077691.n5.n ... -td30.html

[rynhardt]

Hi Rynhardt
Just wondering, are you having your abs cnc cut? What about the corecell?

the foam I'll just cut with a blade, it's real easy.

[rynhardt]

Another thought for you. fibers at 90 are almost useless for adding strength to a board. 45 good for torsion. 0 good for flex control. 90 hold the board together in the case of using only foam core but provide little value after that.

Maybe ditch one layer of mat carbon in favour of uni. Get the fibres going in the direction you want strength.

So maybe something like this

Top
alutex 0/90
200gm carbon mat 45
core
200gm carbon uni 0
alutex 45


Also check out nomad kiteboards layup. They role with stringers of carbon uni at various angles to obtain the strength/flex they want.

http://www.nomadkiteboarding.com/index-aboutus.html

I suppose I'm a bit old school, but I prefer to mirror the layup schedule around the core. At least, that is the way I understand the sandwich construction theory.

[rynhardt]

That is a lot of work and materials spent to use Kerry's inserts. No offence K. (i don't remember seeing them, not sure how good they are), but get the professional industry standards inserts, M6, here:
http://boardbuilders-forum.1077691.n5.n ... -td30.html

The design is tolerant of any insert type. I just happen to like Kerry's because they're an excellent fit for my purpose, and they're locally available.

[board dude]

That looks like its going to be a fantastic build, the wave-twintip style kiteboards are fantastic fun.
For sure in perfect side shore conditions with lines of waves a surf board is great, but side-on, onshore and offshore winds where the waves are popping up and being pushed around a wave-twintip is much more fun.
You can hustle a wave-twintip in very small areas between the waves, you have to be very accomplished with a surf board to get the same possibilities. And of course its jumps and freestyles the same as a normal twintip.
Plummet hit the nail on the head with the concave , super important, the wave twintip mainly from the outline and having the fins much closer to the center point has its pivot points very close together, you need the concave to give the board directional stability, great idea building 2 versions , maybe 2 versions of differing concave.
Would get the core down to 7mm maximum , if you are less than 60 kilos better 6mm thickness going down to 2mm in the tips. What density does the corecell have ??
You have a great rockerline, will be an interesting twintip.
http://www.nomadkiteboarding.com/