Foil Drive Assist, DIY

I was facing similar issues, so I glued my ESC to a 6mm plate with thermal paste + epoxy, now I have to make a hole in the box and glue it there. As you can see in the pic, i removed 3x3mm of the alu plate to improve the bond with the plastic box and avoid sharp corners in the region i have to remove. Hopefully it’ll hold.

I didnt want a hose with salt water inside the battery comparment. I hope this was a a good idea and that the plate will remain watertight. The epoxy is rated to 150ºC, so should be fine. I’ll test it this weekend and report back.

Awesome! I have used 3m 5200 to glue things through the wall of waterproof enclosures before. That stuff is crazy strong (and crazy permanent). Might be a good product to seal your aluminum plate through your box.

That looks like a flycolor/hobbyking 150A esc? under what conditions do you find it starts to overheat?I think others (like @Foil_A_Lot ) are using that same ESC without overheating.

With a 172mm prop… and i was using it to cruise around to see how fast i could go. As a foil drive (10 sec burst) it’d work just fine even with this prop in my 70L board. It could start effortlessy even without a paddle

Btw, thanks for the tip on the glue

Edit: just took a look at the brouchure of the 3m glue and looks like a much better choice than epoxi. I’ll order it online, so ill have to wait till next week to try it.
In the meantime here’s how it fits

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First off, proud to report a successful first test flight today. Did 15 minutes of slow efoil style circles today. It works! I’d like to take credit, but the brains of this operation is entirely my friend Pete, and much of the credit to the group members here for parts, knowledge, and inspiration. It takes a village to motor this kook. :slight_smile:

Jsonnett: we are using flycolor ESC. It seems to have a failsafe built in that once it starts to overheat it goes into limp mode. We found in testing that running it in continuous power, it won’t last long, maybe 10mins, then requires a few minutes before it’ll power up full again. On Pete’s first test, he moved from flat water into the waves with the short bursts as intended and it worked for another hour…so wasn’t a battery issue. His initial testing was with a VESC (not sure of brand or specs but can find out), he was only getting half power. With the flycolor ESC, he said the propulsion was 30-40% more, which is difference between getting up on flat water or not quite.

Pablo: what is your goal with that esc? Is that so the heat can dissipate outside the box? Nothing those brass fittings on the esc, designed for water cooling? Could be a fun side project to figure out some way to build cooling into the project with those.

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Sounds pretty good!

You mind posting your build specifications?

I see several different motors used successfully for DIY foil drives. I’d like to learn from you guys and get the most optimal motor. Looking for light weight, and durability.

Any of you guys with working setups wanna share your thoughts on the weight of your DIY foil drive setup compared to the “Foil Drive”, what components you used, and what you’d do differently on your second build?

I’m hoping to build a foil drive as my next project. I already have the remote, ESC, and battery cells. Just need to decide on a motor, print a mount and a prop, and a remote holder, and find a waterproof box.

:sunglasses::call_me_hand:

@juandesooka the goal is to dissipate the heat into the sea. My board has a low volume so every time I stop the box is submerged. So as long as it does not fail, it’ll be good enough to ride for a couple of minutes, cooled again in a sec, while maintainance free and just as easy to install as before

As for the fittings, yes, it’s a flycolor marine esc and i could have used it, but I didnt want tubes with salt water inside. Also I don’t know how brass will behave in the long term if salt water is left inside. Galvanic corrosion might also clog the cooling line??

@Flightjunkie my setup weights 3.75 kg, but i have a bigger battery (16Ah vs 12Ah in the commercial foildrive). you can find all the specs here DIY electric foil assist. Steps+pictures+cad files . Seems that all 6374 and 6384 work fine, you just have to try different props until you find the one you like.

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Currently working on my drive. So far the motor is epoxied. Motor pod is complete. Next is printing a prop and playing around with sizes. Then finishing up the controller holder. Hope to get some testing in on Friday. Major goal was to make this an affordable project.
Using a Flycolor 150A and a 6374.
I may try making a folding prop once I get everything else squared. It’s been a straight forward project so far.

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Is there any reliable information about which ESC is used in the original Foil Drive Assist?

Not that I know of. I wouldn’t be surprised if it’s something similar to the fly color/hobbyking tho. I just got the identical enclosure they are using from polycase and the fly color fits in there perfectly.

They have an interesting area on their website for service info. It’s password restricted. I bet it has pictures of what’s under the cover on there and they don’t want people to see that it’s just RC Boat parts that make these things tick! Haha.

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I’m using this 150A marine ESC from hobby king.

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It looks exactly like the flycolor esc (except for the sticker)

Someone in the thread promised to open the original Foil Drive and report what’s inside, but never did.
I also ordered a similar box, very good water resistance. The only difference is the metal latches on mine.

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Could we get more info on the boxes (polycast, etc)? I’ve purchased two boxes so far, too big and too small!

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BUD Industries NBF-32408 Plastic Outdoor NEMA Economy Box 10.63" L x 3.93" W

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This is the case I think they are using. They grey model with clear lid. It also looks like they use some printed latch guards to keep the latches from snagging on your leash or something and coming undone.

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I bought a DSE Hibox for $30.
Part: EN-AT-1027
Material: Clear PC top and ABS grey base
Size: 100Wx270Lx70H

I couldn’t fit all the parts in it. My Battery was too big.
I think you might squeeze a 6S3P 21700 in ok.
My 6S4P 18650 battery wouldn’t fit.

I prefer the Explorer 1908, it’s tougher and more room inside for spare cable.

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Did you cut those protrusions?


My choice of this box is due to its width. My board has a small distance from the edge of the board to the leash attachment. I do not want to install the box on the side because of the shift in the center of gravity.

The Bud box i have is just a rebrand of the DSE hibox 1027. I fit a 6s3p 21700 pack in there, with a bms, and a maker-x foc plus. My setup is close to 3kg, I didn’t want it too heavy.

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The Mini-FOC PLUS looks similar to this regulator but costs almost twice as much.
https://tomiboiesk8.com/esc-based-on-vesc-6/