First Build from Luleå / Sweden

After following this forum on and off since it started and pacifimeisters first youtube clips i felt it was time for me to give it a go.

I am not very good at posting things on forums but I will give it a try…

I decided to build my own board, wings and battery pack. and use the flipsky motor and 75/200esc.

Everything is pretty standard from this forum with some small changes. One thing that i have not seen is the way i mounted the Esc and my way of passive cooling it (someone has probably done something similar but i have not seen it). It turned out really well the esc temperature is never over 35°C.

Maybe it can inspire someone :wink:

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Here is the board before glassing it, its made of standard insulation sheets but I added some wooden stringers and plywood with stainless steel inserts for the foil.
The hole in the back is to fit the ESC box.

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I milled out a sheet metal plate with cooling canals and welded on some walls to create a box to hold the esc, in the box I also fitted a Bluetooth devise to be able to change settings on the 75/200 and the receiver for the maytech remote. i then screwed on an acrylic cover with an o-ring to seal the compartment. The cable gland is also of my own design, i milled out some groves for the o-rings and threaded some holes in the sidewalls of the box. This turned out to be a very space saving and watertight solution, you can see how compressed the silicone cable becomes after tightening the screws.
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To get some additional cooling i have a hole in the nosecone that leads water through the mast and up between the foil mount and the esc plate, so when i ride the foil i get a steady stream of water on the underside of the esc plate. To munt the motor i made an aluminium mount on the back and a delrin mount on the front. Connected them with some long bolts and added some 3d printed side covers and a nose cone.

I was hoping to fit the battery box (max004) in the board between the stringers, but when my battery packs (2pcs of 6s8p molicel 21700) was finished they did not quite fit in the box. So for now i just strap the box on top of the board. (this image shows the pack before the shrinkfit)

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The first ride was a success, i could foil on the first try and everything worked great!
I have some propeller tuning, and other small things to fix but i can foil for around 45 minutes with a speed of almost 30km/hour. The front wing I use I designed for kitefoiling, so I might build a bigger one for the e-foil, but this is quite nice and carvey.

This is my brother trying it out.

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Here is a cad model of the foil if you want to take a closer look
https://grabcad.com/library/efoil-v1-1

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Nice build :ok_hand:t2: What prop are you using?

Very Nice build and I am glad you are on the water flying. I am about to build a 2pcs of 7s12p using 21700 Samsung 40T. How do like your battery pack? Any tips about your building process? I see you used a copper buss bar, how did you connect it to the nickle strip? Any more pics of the process?

I have mostly been using a modified Chinese 7" prop that i cut down to 142mm on the lathe and rounded off the corners. It works and it’s so much fun that i “forget” to record data and try different props when I’m out😉.

Thank you.
I am not a battery expert, just trying to implement what I have read about an hopefully build a safe pack.
I soldered the copper wires to the nickel strips because I was worried that the nickel was a bit on the thin side. The soldering was made before the spot welding.
I laser cut two sheets of acrylic spacers for the cells in each pack.

They seem to perform really well, even after a full ride they only get to about 35°c. And the cells discharge to exactly the same cell-voltage.

There is something strange going on when charging, but i think that might be my old rc-chargers fault. One cell in each pack reaches 4,2v before the rest (they are around 4,15 at that point) so the balancing part takes a lot of time.
Just have this picture :roll_eyes: i get so caught up in the building process that i forget to take pictures.

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