”The barge” efoil build

larsb · Jul 6, 2020

I tried to epoxy the rotor magnet gaps to lower drag losses under water, turned ut uneven and it was too late to clean it. f*cking hell! It will be totally unbalanced, it's likely unfixable so i basically scrapped the rotor. :x

I have one more try, i'll do the other rotor with just silicone. if result is poor again i can just scrape it off. doh!

amberwolf · Jul 6, 2020

You can sand, file, or dremel most epoxies just fine.

larsb · Jul 6, 2020

This is a rubber modified epoxy, doesn’t sand so well and i doubt i can make the rotor round again by hand..

Clanarn · Jul 7, 2020

Maytech has some nice e-foil dedicated motors and propellers. 65162 for example. I think there it some videos of them on youtube also.

larsb · Jul 7, 2020

Yes, but the maytech and other clones are quite expensive and efficiency seems poor from the dyno sheets. I think they might have been tested at too high current/torque though.

80100 is a quite good motor for the price and i had it already :thumb:

larsb · Jul 7, 2020

I got a new pwm dimmer rated at 24v/30A. I don’t see a use for more power really for the hotwire cutter. Hopefully it works together with my computer charger, we’ll see when i do the next board

larsb · Jul 8, 2020

Motor mount for the mast is finished. I hope it fits, had to draw it from an outline sketch of the mast and i was aiming for a tight fit so it’s not 100% sure.

I have glassed first layer on the top, now i’m cutting cloth and vacuum bagging material for the bottom. Quite happy with the progress so far.

larsb · Jul 9, 2020

Prepping for glassing by sanding the sides and top layer. I haven’t done this size of glass fibre build before, it’s a fair bit of work. Just making a two meter vacuum bag took about an hour :wink:

V-cut in the rear is to evacuate water from around the electronics box lid.

larsb · Jul 9, 2020

Bagged and ready, i had a couple of holes in the bag that evaded my sealing attempts for too long. I’ll not be suprised if i need to do some touch-ups tomorrow when i see the result.

larsb · Jul 10, 2020

Made a spacer plate for the mast mount to be able to route the wires into the mast without cutting a large recess in the board. There’ll be a cut in the rear (left) side of the plate that’s not done yet in the picture.

larsb · Jul 10, 2020

Some dremel grinding later, recessed also the mast mount to make it easier on the wires.
They are 6-7AWG/10mm2 cross section so it’s a tight fit both into and through the mast.

larsb · Jul 11, 2020

Final glassing, electronics bay done.

the cloth in the bottom didn’t want to lay completely flat so i added some weight on top of it.

It’s time to get the motor and electronics connected

larsb · Jul 11, 2020

This section of ES is dead these days. I can understand why everyone went to efoil.builders but i really don’t like the ad driven forum over there. ES is way better in this regard :thumb:

larsb · Jul 12, 2020

Mast mount nuts and cable outlet glued,

mast mount and spacer plate finished.

Tomorrow it’s electric time.

larsb · Jul 13, 2020

Added some coats of electrical varnish to the stator for waterproofing

I’ll switch to stainless bearings also but later, need to order them.

larsb · Jul 13, 2020

Motor mount fits perfectly on the mast

Instantly i wish i’d done a larger cutout for the phase wires in the motor mount but it’ll fit anyway.

larsb · Jul 13, 2020

Drive unit put together:

I cut the hole for the wires in the mast with my dremel, that’s a 400 euro cut :wink:
Started to thread the wires inside the mast but realised i need to open up a bit more in the top to get the last wire through.

larsb · Jul 14, 2020

Final push to get the barge ready for water!
Wired motor, and most of the rest. Only throttle and phase connectors on motor side left

larsb · Jul 19, 2020

Finishing the two printed props with some layers of epoxy glue. I’ll also receive a professionally printed nylon prop tomorrow, should be enough for some first trials.

I’ll buy a prop once i know what i need as balancing and surfaces will never be 100% on the printed props.

Unfortunately i'll now have to wait for two days for the throttle cable, it's being shipped. I have a VESC ESC with receiver and handheld remote but i don't feel like learning to set it up yet :wink:

larsb · Jul 20, 2020

Sanding the ridges and defects after the vacuum bagging took an hour, it needs a finishing coat to look OK but i don’t have any tools or epoxy where i am now - it will have to do :wink:

larsb · Jul 22, 2020

I compared inductance of the motor and extension wires to previous proven settings for the controller. It's way higher than expected. I wonder if my measurement was correct and i didn't bring the meter here. Hopefully i can do the first trials today, we'll see then.

neutro · Jul 22, 2020

Great build, I'm interested to see how it performs.

Thanks for documenting it.

larsb · Jul 23, 2020

everything is assembled and ready

First trials today!

I cannot take any pics since i crashed my phone and my family is out picking cloudberries. Let's hope i don't need any emergency rescue

Biggest win of the day is that i still fit in my 15 year old wetsuit (even though i remembered it to be a bit roomier :wink: )

larsb · Jul 23, 2020

first runs done, total success!

The board barely floats with me but it was no problem to stay on it or get on my knees. Enclosure stayed completely dry. There was a bit of power lacking from the drive to reach flying, i need to set the controller parameters better.
I'll do some readouts, charge the batteries and try again :flame:

larsb · Jul 23, 2020

I set some new parameters on the controller, it runs so much better now that i am really looking forward to tomorrows trials

”The barge” efoil build

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