Tobi's build from Berlin

Hey guys,

First of all i want to thank @pacificmeister to start this forum, you have created a great source of inspiration!

Then thanks to those i’ve gotten a lot of ideas from, @Wardy & @edivory i’ve copied a lot of your solutions.

@Flightjunkie , thanks for bringing CorrosionX into my life :slight_smile: and your Remote Hack, @michion thanks for your amazing seal! Congratulations for @Flying_Rodeo for your brilliant Motor and @kiterr for your amazing Wings.

As well as i want to shout out a big thanks to all the guys in the german telegram channel!

I’m a mechanical Engineer from Berlin, Germany and have lots of experience building Drones, FPV and big Octos alike, as well as a passion for Wakeboarding and Foiling.

Here’s my finished first Setup:

Anton WingFoil Board 5’0/ 80-90L/ 149cm x 60cm x 12cm
Got that used on ebay with little damage.

FR Motor System and RL Fuselage and Efoil Wings

14S14P Samsung 18650 25R

MGM Compro ESC TMM 14063-3

On this topic i want to cover the solutions i found worked for me and share about the build from the beginning to the end.

My biggest challenge was working with carbon fiber for the first time on this scale. Also getting everything 100% watertight was never necessary in my previous builds.

Here are some pictures of the finished board and the first test ride yesterday.

More exact description of the built will follow…!

And last but not least the video:
https://youtu.be/r0RXpcUDjqU

14 Likes

Talking first about the elephant in the room when building an efoil.

I’ve played with the idea to build a board from scratch but was shocked by the amount of hours that go into shaping and laminating a board so i cheated and got this beautiful handmade carbon board from a small manufacturer here in Berlin. Thickness of the board is 12cm, so i figured it will fit battery and electronics.

Getting rid of the old traction pad was quite a challenge but acetone really helped. Be careful though it might ruin the paint job.

After that i decided for the size of the compartment, i found an electronics box for the battery made from polyester which was the reason i made the cutout for my cavity 70x40cm.

Unfortunately i haven’t got a cnc yet but i found out, that two old steel rods also do the job. :slight_smile:

From another fellow german builder i got the idea to use an 8mm metal drill bit which i grinded the top of, for using it to router out all XPS foam.

I quickly realized that i wasn’t able to use the foil track box which had a total height of more than 3cm and would limit my height inside the board. So it had to go, and instead i glued a sandwich of 3mm carbon sheet with 6mm plywood on top into the cavity using epoxy.

For fixing the mast later i installed m8 stainless steel drive-in nuts.

As i already had the electronics almost finished i decided for their final positioning and used m5 screw-in nuts which i also glued with epoxy into the plywood. I covered them with a bit of tape so during laminating i wouldn’t fill them up with resin. In total i made 18 inserts.

Next in line was the lid, where i’ve reused the old carbon deck. Its also a sandwich with 1mm carbon sheet, 9mm waterproof plywood and the 1mm old carbon deck. In total 11mm, a bit on the heavy side, but i wanted it to be super sturdy and 0 flex.

These are the latches i bought, they feel high quality and so far they’re waterproof.

And i’ve used gemlux hinges:

To fix the hinges onto the board i’ve glued plywood with pre-installed m5 drive-in nuts between the deck and the XPS.

The holders for the latches are stainless steel angles which are screwed into a piece of plywood same with pre-installed m5 drive-in nuts glued into the XPS.

Before laminating i’ve used epoxy mixed with microballoons as a filler and sanded the whole cavity to make all surfaces super smooth. And i took out all sharp edges which would have been a pain in laminating with cf. Speaking of cf, since it was my first cf job even involving a vacuum pump, i played it safe and ran several tests to find the desired layup and to figure out how to get the rigid cf sheets into the corners.

The final layup is 200g carbon fabric twill 0/90 + 200g bidiagonal carbon fabric +/-45° + 200g carbon fabric twill 0/90 + 100g glass fabric twill.

The glass is just a final protection layer for the sanding that needed to be done after removing the peel ply.

It really helped to cut a template and to precut all sheets before laminating.

I’ve decided for a simple hand layup and vacuum bagging to get the shape right. After the initial cure of the epoxy, final curing was done at 60°C in the sauna. :slight_smile:

Finally filling the surface the peel ply had left with resin, sanding, filling again and sanding again to get a really nice and smooth finish.

Now it was time to find all those hidden inserts under the cf again, luckily i’ve made a template as well. So it was easy to cautiously drill out the cf.

At last i copied michions method of pouring silicone into the space between lid and board to make a perfect seal. I’m very happy with this solution, Wagnersil 32N was used:

So much regarding the board, off next to the electronics and battery…

6 Likes

Looking at electronics and the battery, this was the fun part for me!

Actually i also cheated a bit, luckily i was able to get a battery from last season of another efoil builder in germany. But it took me quite some time to find the right battery case because i wanted it to be fully waterproof and serviceable.

So after hours of research i found this german producer that makes this super high quality box. I can totally recommend their products since i’ve also used their aluminium housing for the ESC:

I’m quite familiar with Lipos but wanted to go for Liion with this build. Now talking about thermal runaway i also didn’t want to create a bomb by sealing of the battery completely.

Luckily i found this turkish producer bimed on a post on the forum who was so kind to send me a trial of their Ventilation and Safety Device (VSD) which i installed.

The battery itself is built with Samsung 18650 25R which gives the pack a total of 35Ah and around 2kWh. Its been build with a 100A Ant Bluetooth BMS which works fine. I’m totally aware of the danger of these BMSs hence i’m keeping the battery at all times in an ammo can and in my next project, which will be my own battery build, i will most probably use a BMS solely for charging and when discharging run a dumb battery.

I’ve used Amphenol plugs and installed a 120A Shunt on the negative lead inside the polyester box. Finally i drowned the box for 1h in 30cm deep water and no drop inside.

Regarding the motor, i’ve followed the advice and checked for fluid inside the FR motor and i was pleased to find it filled up with machine oil. I drained the system and replaced it with CorrosionX.

A bit more challenging was the mast seal, unfortunately the FR System came without a seal so i had to come up with my own ideas. I started by cutting out and inserting a foam barrier into the mast alongside the watercooling pipe and motor cables then filling the notch with Sikaflex silicone. Finally i milled a cone into the board and installed a temporary foam seal on the mastplate. Then i fixed the mast under the board and left 1-2 mm distance and poured Wagnersil into it. Still about to find out if this will waterproof 100%.

In the electronics box i’ve installed the ESC as well as the maytech receiver which is powered by an UBEC. I wanted to follow KISS and keep it as simple as possible in the beginning. I filled up the electronics box as well with CorrosionX and extended the antenna onto the very front of the board which works flawlessly. I had not a single connection failure so far.

All cables are 8AWG which i was a bit worried about soldering those, but i found that pressing is much easier, so i’ve used this hydraulic press to get the connections nice!

Regarding the Maytech Remote, i’ve followed instructions of waterproofing it. Let’s see how long it will last. :slight_smile:

Still waiting for @Felixfoiler to finish his game changer.

Last tests before going out to the lake have been done in the basement:

As a little Sneakpeek, here are some pictures of the 2nd gen board.

I’ve fitted a Flipsky 65161 120kv with FR Prop to a 90cm Slingshot Mast, the board is a Ride Engine Moon Buddy 5’0, which i also got used on ebay…

Thanks to @michion for the .stl files!

6 Likes

I almost forgot the first wipeout pic:

:grinning:

15 Likes

Awesome looking build mate!.
I like the hose connector you’ve used, was wondering where you got it from.
Dan :+1:

1 Like

Cheers mate!
I’ve been studying your build to the fullest and tried to copy as much as possible. :smiley:

A lot of build time I’ve actually spent online searching for these little parts. This stupid water outlet was one of these things on which I almost gave up.
I actually bought it in a German motorsport shop, but I’ve done a quick research and found it for you on a UK online shop, here you go:

I can’t claim all the ideas on my build were mine as a lot came from viewing other peoples builds, but glad it helped you all the same.

I’ve already got one similar which I also bought from Germany but it’s only 3mm but the one you linked is what I’m after, longer and larger diameter.

Hoping to get my second build all done by the end of the month, just waiting on a few parts :call_me_hand:

Man, i’m already sitting here with popcorn waiting for your post of the new build! :smiley:

2 Likes