MP70131 anyone tried

10N12P Sold by Freerchobby, anyone tried?

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Looking interesting. I have requested some other details and internal photos.

I asked for dyno test they don’t have.

From the pictures, the biggest problem is that they are potting the back of the motor. That means its just not serviceable if there is any bearing failure.
If it can deliver the right power though, then its a much nicer price!

Could be only potting of the lead exit, there is some socket screw on the perimeter at the back so perhaps still serviceable.

Tried not watertight, not enough power, could hardly foil

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Thanks for sharing, did you give them a feedback? What did they say?

Damn, thats very disappointing!

Do you have any pics of the internals? Size wise and spec wise it should be able to handle it. What prop were you using?

Well i need to add some informations to my last feedback

I used a 3D printed / carbon fibered props 130mm diameter and pitch range from 5.5 to 6 inches
those props are very efficient on similar 120kv to 130kv motor (inrunner, outrunner) @ 12s

i have no pics sorry, the leads are very thin and the motor draws a LOT of ampere if we use a higher pitch propeller.

Chances are at 70Volts this motor is a beast, but at 12S it lacks some torque, and at startup the amp draw is higher than other motors to achieve the same speed.

We use VESC’s with gentle params ( 120 Amp motor max and 100 Amp battery max) we could reach 27-28kmh
To compare with our other inrunner we can do 60wh/km @26km/h were this one needs 80wh/km @24km/h

Regarding waterproofness maybe it can be done by gluing front and back parts, the shaft seal seems fine.

Thanks for the update.
Got any pics of the other motor you tested against?

I’ve been in touch with them and they say it is 100% waterproof and they can make it at 100kV for $210 plus $30 shipping (to Ireland). Thoughts?

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Did you ask them about the thin leads? Can they change to thicker?

They can put 10AWG leads on the motor leads if we want

I have been running this motor on my efoil for about two weeks now and it has performed flawlessly and also with no leaks yet. I needed to use a 6.5" dia 10" pitch 3-blade (ABS printed) prop to get enough thrust to foil (I am 145 lbs). I believe I have the 100kv version but have not measure it to confirm. I plan to try larger & greater pitch props, because it is just enough now to foil at full throttle (48V, 12-cell system), although it is perfect for learning to foil. Static (board not moving) motor load is 60 amps (haven’t yet measured load at foiling speed, but I would venture a guess at about 40A based on how long my batteries are lasting). I would definitely recommend this motor, but as with all propulsion systems, the correct matching of the propeller pitch and diameter are absolutely critical for good results.

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Are you sure about the 10’’ pitch ? It would give you without slip and rpm drop 73km/h … way to much , 6’’ seems more appropriated

Yes, I am sure about the pitch, since it is easily measure-able on the solid model.
Below are rough calculations of where this system is operating (which include some estimations):
100kv @48v =4800rpm no load
3360rpm loaded (assumed ~@70% of no-load speed) = 56 rev/sec
blade angle at perimeter = 25 deg, angle of attack = 5 deg, so advance angle = 20deg
Circumference at perimeter = 6.7" * 3.14 = 21"
[pitch calculation: 21"/rev x tan 25deg = 9.8"/rev]
prop advance/revolution = 21" x tan20deg = 7.6"/rev = .63 ft/rev
.63ft x 56 rev/sec = 35 ft/sec = 24mph = 38kph*
This does not seem unreasonable for foiling at ~15 - 18mph (in choppy water and wind)

*this is not the speed of the board, this is the speed of the water moving through the propeller flow. The water in the prop flow reacts by accelerating backwards (some may call this “slip”).
[This is why a larger prop has generally higher efficiency, since a higher swept area and thus volume flow (and thus mass flow) of water is reacted against, so requires a smaller reactive acceleration (which means less loss, or “slip”)].

They way I see the term “slip” used, it seems to include both angle the attack requirement of the prop plus reaction volume flow requirements, since it is used to account for any difference between the theoretical pitch speed and vehicle speed. (sometimes it even includes motor loading induced rpm drop!)

It is possible that when I increase the prop diameter I may find that less pitch will be optimal, although that has not been the case for the first two props I’ve tried. (One that was 10% smaller in pitch and diameter had similar ride time but very marginal thrust, so also lower efficiency). I plan to try at least a few more props (some significantly different blade designs) and add some more objective measurements (such as current logging) to increase understanding in order to optimize the system for maximum ride time.

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This motor was taking water after 20minutes in a lake, there is only one oring seal and it seems to have a tiny diameter to do the job.

It was also impossible to run FR propeller 150m 6” pitch whereas the kv was in the 125 zone. I could foil with it with a tiny propeller with 5” pitch but it was tricky to go on plane (67kg+20kg)
I assume the difference is due to different winding, resulting in different performance

Thank you for the formula , I am not really good at that , I tested several propellers and calculated pitch by measuring , the pitch at the tip was always higher that what was the propeller given for , work best to do the average across of the blade
Do you know your blade Area and your « rake » ?

Any insight on how you mounted the motor? I’m working on a higher voltage VESC that could maybe match this motor really well if it does indeed work ‘like a beast’ at 70v. It was possible to foil? And what prop did you have most succes with?