RIWI’s third build

Would you have pictures of box + lid fabrication ?

For the box I made a mold in wood which a sanded with 400 grit, painted and waxed before laying up the fabric. I don’t have time for two part molds so I made small holes, three per side, through which I blow air in order to release the finished box from the mold. Works like a charm. This is the mold, you can see the first layer of peel ply.

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After the box is released and fitted to the board it looks like this:
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The lid is another story. I always do the lid after the board is almost complete, this will give the best fit.

I make a “plug” in eps that fills the box. I don’t make the plug flat, it’s stronger if it’s a bit curved.

The eps is covers with vinyl, epoxy does not stick to it.
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After this I apply epoxy, fabric, core material and so on. I used vacuum to extract any extra epoxy and air.
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How far is the middle of your mast plate to the back of the board?

Approx 16cm

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It is way back! So I’m assuming you are standing further back on the board? Any pics of you riding it?

Same as my two earlier boards. Works perfect.
This one has not been in the water yet but you can see pics and videos of the other two at instagram.com/wildtech.eu

I also think that it is good to have it so far at the back. I always have to stand so much at the front.

Mast as far back as possible is the best solution :+1:

First run last night. Current was to low, set to default 80A by Vesc motor wizard. Did another test this morning, setting the current to 120A. Still not enough power to get it planning.

Have now loaded the “no limit firmware” and set current to 150A.

The board is small, only 53L, so it will require a lot of power to rake of. Hopefully I can test later today.

Setting current via metr work fine.

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Back in the water again after the maytech failure.

Now running the yep 120 modified with a larger cap bank and heat sink. Works great!

I got a “problem” in speeds over 27kmh. I sound, and feels like air is being sucked down trough the mast and interfering with the prop. The faster I go the more it sound/feels.

Could also be disturbances from the nut pockets in the prints?

Has anyone seen this? what did you do to fix it?

Thanks

Rikard

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The fastest way to see if its the nuts is to put tape over them and take a ride. Another option would be to remove the duct and see if it’s causing issues…

I started by putting tape over the bolts that hold the fuselage to the mast, I have 2 extra holes now since I use the mosses fuselage on the gong mast, didn’t do much.

I’m thinking air is being sucked down trough the mast at high speed. I will try to make the mast airtight at the top, that would be easier then trying to seal all holes down below.

Yes seal the top of the mast, that will solve it. Air will get sucked down at higher speeds which makes this strange sucking sound.

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What about facilitating the phenomenon with an air intake to see where it takes you? I have in mind the skwal torpedoes :thinking: :blush:

what temps were you seeing? I’m running the same ESC and have had a hard time keeping it cool. Ended up adding a water jacket to the bottom of the AL box I’ve got it in, but still had to raise temp limits in VESC tool to make it ridable.

Up to 85, I used water cooling as well.

I think it’s poor design, riding my yep 120A now and it works like a charm.

Sealed it and now it’s smooth and fast. Thanks

Board holding up great! Remote is plastic bag works well :slight_smile:
Propshaft is a bit wobbly, a teaspoon of water passes the lip seals. I add some oil every two weeks to keep it from rusting. Might rebuild this winter.

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Which wing are you using most now?

Im on Gong PRO M. I’ve been focusing on turning and the PRO M with surf stab is very good for that.
I’ve done some runs with moses but thats a totally different thing. Much more unstable and challenging. Might be right for next year :slight_smile: