First build, an assist-class device, mounted under board

I wanted a surf/downwind assist class device that would be powerful enough to get up on foil without much paddle power added, but not something designed with capacity to use the motor continuously e-foil style.

I’ve been able to order and build in about a month thanks to some holiday free time.

I’ve been keeping a running gallery here: https://photos.app.goo.gl/ZcJgQTueWQrv15i27
(some comments in photo description).

I may not have ended up with the right mix of components in this attempt, as I’ve got some power issues (I posted details in the propulsion topic if you have some thoughts).

No cad or 3d printing, just checking some dimensions of parts, and plenty work to remove as much aluminum weight as possible.

Hoping I can debug and get this lifting (may need to swap one or more things out).

-P

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Would suggest to swap the motor with a 6384 or 63100 outrunner, use a smaller prop (Flite prop works with 63100, 140kv). Then use a more aquadinamic mounting, maybe clamp the motor to the mast, you could still run the cables outside to keep the nice carbon mast intact.

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yes but the 63100 from flipsky is not waterpoof (change clip;bearing SS; inside epoxy coated) ? for the clamp mast attach ; since there is no holes at the back at the motor…you fix it from the front ? any design for that ? thanks

This one has, at least the one I bought: https://alienpowersystem.com/shop/brushless-motors/63mm/aps-63100-outrunner-brushless-motor-140kv-4500w/
Cut the shaft after the circlip, change the bearings, waterproof with epoxy. The propeller is attached to the bell with 4 M4 screws. The stator also has M4 screw holes.
See here: Daniels (un)geared inflatable (slowly built) - #55 by sat_be
Instead of the shaft I attached, there are 3D printable props that can be directly fixed to the bell with 4 screws.

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I’ve continued to poke away at the trial and error process of finding a prop that is optimized for this motor

Initially I was trying to cut down various off-the-shelf props to reduce area to match the low-ish torque. But these all had too steep a pitch on enough of the blade that by the time I reduced area down to a point to get the RPM I was looking for, there wasn’t much thrust. I’ve now turned to 3D printing, initially just scaling down the original CC @superlefax model, but this too was for a more powerful motor than mine

I’ve now gone ahead and just started designing prop variations from scratch in CAD (top left in image)

Here is a link to the design of my current 2-blade leader of the moment

I still haven’t tested this in open water, but my testing has involved seeing how many amps I can get the unit to draw in a large tank (aka hot tub) and still kick out a decent (qualitative) jet/plume of water flow.

Most of the props I cut down could never get over 12-14 amps, the current design is getting over 20

My read on what is possible from the motor is based on tests with semi-submerged props where I can see into the mid 20s on amp draw (from vx3 remote getting VESC data). This semi submerged state seems to be able to reach the blend between RPM and resistance/effort.

If this produces the thrust I’m looking for, I’ll prob then try a 3 blade version - or maybe a folding version, and then get it commercially printed in one of the reinforced nylon materials. (currently using PETG, which is holding up much better than PLA due to flex).

I’ve also ordered a non-waterproof 6384 coming on slow-boat that I might try waterproofing myself (what I originally wanted to avoid) as the lower KV (120) and outrunner nature should give me a lot more torque to work with.

In the end, I’m looking for something much more optimized for hole-shot to get up fast, than any kind of top speed like one might be looking for in an steady-state e-foil application (as this is assist only).

I used a couple of black prop ( solas, trim and cut in diameter) If this can help you with this prop : start to kick after 2500rpm and with 3000rpm aim for 20-22km/h , nice push but low speed
Log and results in my post « very slow built from France »