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Mast Building Method

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plummet
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Re: Mast Building Method

Postby plummet » Mon Jan 30, 2017 9:21 pm

I think 2-3mm carbon per side of your core is what you want to aim for. I also think 70% uni at 0 is not the best layup. Twisting forces are big on the foil. You need to counteract that. Uni layed up on an angle say 15 deg for several layers will give better results for twist but also still be in line enough for flex.

Downunder. Don't worry about the weight. stiffness is key. You can't have a mast thats too stiff. But you can have one thats too much of a noodle. Even with my solid layup my entire foil/mast weighs in a 3kg. That is in line with with production carbon foils. The difference between ultra light and flexible and stiff and very good may only be 400gm in weight.

I ended up doing an additional layup because I wasn't happy with the twisting of the mast with my initial design.

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Re: Mast Building Method

Postby Blackrat » Tue Jan 31, 2017 7:10 am

plummet wrote:I also think 70% uni at 0 is not the best layup. Twisting forces are big on the foil. You need to counteract that.
+1

Your mast will be way stiff enough because it's only 700 long , when you start going over 900mm you need to pay more attention to layup

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Re: Mast Building Method

Postby TomW » Tue Jan 31, 2017 11:19 pm

I'm going to measure the flex, but I think it's brutally stiff, even after I ground off some of it.
The plan is to add 6-8 layers on fillet, fair it out, then a cosmetic 200g twill carbon.

I understand why a mold is better approach now...

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downunder
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Re: Mast Building Method

Postby downunder » Wed Feb 01, 2017 2:12 am

TomW wrote:I'm going to measure the flex, but I think it's brutally stiff, even after I ground off some of it.
The plan is to add 6-8 layers on fillet, fair it out, then a cosmetic 200g twill carbon.

I understand why a mold is better approach now...
:)

Good to hear mate. Even 1-2mm mast thickness difference makes a huge change to stiffness. Is 4mm CF on each side?

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Re: Mast Building Method

Postby TomW » Wed Feb 01, 2017 8:22 pm

downunder wrote:
TomW wrote:I'm going to measure the flex, but I think it's brutally stiff, even after I ground off some of it.
The plan is to add 6-8 layers on fillet, fair it out, then a cosmetic 200g twill carbon.

I understand why a mold is better approach now...
:)

Good to hear mate. Even 1-2mm mast thickness difference makes a huge change to stiffness. Is 4mm CF on each side?
Yes, it was 4mm each side. Probably down to 3mm in some area, still 4mm other..

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Re: Mast Building Method

Postby TomW » Wed Feb 01, 2017 8:57 pm

So, if I put on 3mm of Cf onto this fillet, tapering the thickness from zero 200mm up the strut to 3mm onto plate. Then add a 200 twill cf over entire thing.
What are the odds of this breaking apart during Newby use probably bouncing off some sand...
2017-01-28 16.04.59.jpg
2017-01-28 15.01.59.jpg

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Re: Mast Building Method

Postby TomW » Thu Feb 02, 2017 11:16 am

Question: how can I dryland, static test the strut to plate to board connection? Mount to board. Clamp board in place with strut parallel to the ground, add weight to strut end. How much?
Don't want to destruction test it. Just make sure I'm not going to lose my foil...

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Re: Mast Building Method

Postby downunder » Thu Feb 02, 2017 2:28 pm

I think if it floats that's all you need....Paint it for some visibility. Out of ideas, sorry :(

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Re: Mast Building Method

Postby Mossy 757 » Thu Feb 02, 2017 2:48 pm

TomW wrote:Question: how can I dryland, static test the strut to plate to board connection? Mount to board. Clamp board in place with strut parallel to the ground, add weight to strut end. How much?
Don't want to destruction test it. Just make sure I'm not going to lose my foil...
Tie a tight bowline around the strut with a piece of dyneema then tie the other end off to your rear foot strap. If the thing falls off, the line should keep it attached to your board, so long as the strut/plate junction doesn't break and the line slips off.

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Re: Mast Building Method

Postby TomW » Thu Feb 02, 2017 4:50 pm

I was thinking about a leash....at least until it does not break off after first 10 rides and when i actually learn how to ride it and not bounce off the sand.


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