How do you cut the shaft? After disassembly, with a disc?
With such a strong welder why didn’t you weld copper sandwich?
yes, cut with metal disc. 2mm above the secure ring, also changed my adaptor to make room as it is not flat with the top of the motor.
I am not familiar with copper sandwich, maybe next battery, but I think pure nickel will do the work and is less likely to get rust than copper
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power on video
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FYI your channel marked as for kids, no comments etc.
Thanks for letting me know - changed
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So… after connectivity test. Its time ti start getting things wet.
Connected the motor wires. Each wire got shrink tube with adhesive. Then all the 3 got shrink tube. I poured some silicone paste inside the tube, edges shrink was first. Then the middle such that silicone popped out from edges.
And doubled with another shrink.
Processing: IMG_6541.jpeg…
Processing: IMG_6542.jpeg…
And. Wet we go - wet test
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And some fun. This will be nice use as well
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So test #1 in the ocean failed. I couldn’t go beyond 30% throtle.
That was surprising because previous test in a pool was a success from this point of view
What has changed?
The pool test proved that i couldn’t go by without adding external heatsink. So i followed other builders here. I cut a hole in the box and glued external heat sink. Moved the small board with input capacitors to a wires ( so i have room to attach the controller to the heatsink) - that seems to solve the issue!!!
The controller didnt have any contact with the heatsink thus i was getting immediate cutoffs. Outside the water it was running full throttle, which proves that load increased current, and created heat which didn’t have where to go.
So did some mechanical changes. Changed a 3d printed part to allow more room for pressing the controller against the heatsink and went on to next experiment.
This experiment didn’t take too long… Infact 5sec of runtime and apparently the well recommended ubec ( in thia forum) died - weird!!
I am trying to understand if the controller created a spike that burned it…? Although it has capacitors i. Its input which should also protect other agents connected…
Another option, is since this is a tiney ubec, the ouput wires are very close to each other and maybe in the box it was pressed and created a short…not sure…
Starnge…
Any one here had this going on?
And here is the pool test (original heat sink in a closed box)
About this propeller, who’s design is it? Can you share files?
About your problem with overheating, this controller known for it’s bad things.
Bec should be wired between battery and receiver. Esc wired to battery. Thus a separation of power lines.
And I can give you xcross or bec if you will need.
Hey Pavel, Ma kore, Thanks for the advice.
I took the prop from @hangloose share.
For overheat issue, it was my bad! not related to controller, as I changed the orig heatsink, I didn’t do good job in attaching the controller to the new heatsink - after some mechanical changes to ensure it is well attached I don’t have this issue any more.
For now (until I get new BEC) I simply fed the receiver with a 9v battery - it works!
I am still trying to understand what could have burned that receiver. Of course the BEC was fed from battery but as a matter of fact the controller is parallel to that, and maybe the fact that I moved the controller input capacitors to be on wires (rather than straight on controller input) , allowed more room for a spike to travel and burn the BEC (on other hand that battery should be able to keep the voltage honest 
and the BEC is 2-12S, so should support even 50V…) .
The XT90 connector I use has pair of wires going to controller and other wires feeding the rest.
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BTW: I had a good test in the ocean, everything worked, I just had the box not well tied to the board and it was rolling over on my legs, so had to give up.
will find a way to better tie it.
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Regarding the choice of BEC, Ive seen talk of people using what I consider are really large ie 10A devices.
Why so big? Arent these used for more that tapping 5V for a few hundred milliamps of RF power?
I think you are right. You dont need more than what the receiver power is…
Adding some videos of a try out, in the ocean.
It ended up with a fire as one battery cell just expolded…
I am guessing that i had water leakage and that shorted that cell.
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It must be very annoying when the battery catches fire on your back.
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