Volker’s Build - 80100 18650-30Q

The Wall on one side, is to push water into the mast. Its angeled, so i can print without supports.
Small holes in the mast act as sieve

The other side has no wall, cause there are the cables.


Prop Cap

Since the one i found, didnt fit, i tinkered one myself.

Propeller mount


I was thinking that yesterday when doing the air / water test… it’s time to redesign one :slight_smile:
I was about to get the front piece of the rotor out to see that it’s really flush on the inside.
did you measure the power when spinning it in water?
you’re not worried about lack of water circulation?

Get all surfaces as smooooth as possible. Even the stator notches can be filled without thermal worries, just leave a channel open so the wingdings get to water.


Spinning in Air: 162W
Spinning under Water full throttle: 825W
Spinning under Water half throttle: 250W

Test was with 44,4V only. (Battery wasnt charged up)

Stator and Magnets only covered with one coat epoxy. Nothing fancy, just KISS

There is a small gap, about 0,75mm, that should give enough waterflow. At least i hope so

so slight improvement compare to mine underwater… not sure if it’s the fit of the cap or may be some loss between my batteries and motor… :slight_smile:

Waterflow of this cheap pump is really amazing

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They say “Frischwasserpumpe” so ‘Fresh water pump’:

  • do you think that sea water will be a pb ?
  • is it a self-priming pump ?

Yes, selfpriming.
Freshwater… I guess seawater would be no problem. Inside it should be plastik anyway…

I’ve opened one up. It’s all plastic so salt water shouldn’t matter.

I guess anyway, everyone is using the same pump :joy:

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Mine only switches on if the heatsink gets to 40 degrees. So it’s never switched on :slight_smile:

Just make sure you flush it with fresh water from time to time to avoid salt to block it.
That’s an advice i didn’t follow and i think i’ll have to clean mine as my tubes looks ok, but the flow is getting lower…
I’m always surprise at the qty of salt I get at the bottom of my mast when the water slowly seeps out …


I wanna stay on the safe side…


1620g pure beauty:


OK, today was first test in a bucket…
and now: The motor sounds like a old barn door. Further Investigation: The big bearing seems to dissolve into rust fast as hell :roll_eyes:
So i guess, i’ll have to wait for new bearings

Update next day
Now i cant turn the big bearing anymore.
Lucky me i already disassambled all bearings and gave them a final Destination:


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As I said before just remove this bearing and the cross part around it, the motor will run just fine and will win hundred watt in losses.
The can will still be maintened by the back bearing. We

I am afraid, that it will wobble and ruin my epoxy coating or even more :astonished:

Only for you @Mat, or cause i had to open the motor anyways:

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