MP70131 anyone tried

Yes i could foil, but it was really hard to get my 68KG on a plane… That day i tested 5.2" and 5.6" propeller, the only one that was working “nicely” was the 5.2" top speed only 27kmh if i record well
We got really better results with a 63100 outrunner…

Thanks for the super quick reply and good insights. Shame the motor didn’t perform. Reading back your messages could it have been a lack of current (your 100-120a limit) or does this motor just not supply the necessary torque?

What battery pack & esc are you using with this motor?

Please post some pics of your setup. I would love to see these…

I am using 4x Hobby King 16Ahr 6s batteries (2p x 2s) for 32Ahr @ 48V. I got them on sale for $120 ea. I like them because I can charge them in 1.5hrs, although connecting 4 balancing plugs every time is a bit of a pain.

My choice of ESC was guided by wanting at least a 3x current margin, and no external cooling required (for simplicity and reliability).

I started out with the Turnigy Fatboy ESC, which worked briefly until it re-programmed itself to 0 degrees timing and then wouldn’t work anymore at anything more than 1/4 throttle (there has been no way to re-program this thing, although a programming card finally became available last week for the first time in a year, which I will test it and report if it works).

I then moved on to an Alien 16sCAR 350-Amp ESC, which has worked well, but sometimes has problems starting this particular motor due to the slow rotational speeds of this low KV motor operating on relatively low voltage (the ESC thinks it is not turning during the start-up sequence and gives up). I am working with Alien to resolve this software limitation by adjusting the minimum speed threshold. Props below 6" diameter start relatively reliably,

Not wanting to wait indefinitely to see if Alien ever gets around to fixing their firmware issue, I splurged and picked up a Scorpion Tribunus 300A ESC, which is tiny, waterproof, easy to program (also requires no cooling), and works great. Expensive though! They have some significantly cheaper smaller units that would probably have worked, but I didn’t want to take the chance on having any more ESC issues.

Now that I have my data logger hooked up, initial data appears to show I am somewhat over-propped (running an 8" x 10" 3-blade, which is the biggest one I’ve tested), although I can’t log RPM yet. The current only drops about 10% when foiling, and I think it should be more like a 50% drop with the correct prop. I have tested down to 6" x 7", which also got it up on the foil with very good acceleration, although I could not measure anything quantitatively back then, and had other issues getting in the way such as throttle remote reliability and calibration.

Motor is still working perfectly, btw! (after ~20 hrs of mostly salt water use)

I will try to get some pics together and post them.

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Side%20view front%20view

Front of motor is glued & screwed to 3D printed mount (urethane marine adhesive and 4 small button heads, which I would not trust alone - too close to the edge of the plastic!), and also has a few turns of metal tape around the joint for a little more strength and heat transfer (put on before the screws).

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I think I’ll be following your build closely so apologies in advance for the annoyance of constant questions. I managed to haggle and get the motor delivered to Ireland for $200. Just waiting on paypal invoice to pay for it! thanks for the pics - unfortunatly, I have to ask…stl file for the mast clamp? I understand if its a no!

Sure, I will post stl files, but of course it might not be perfect for your mast. Let me know if you want a file format that you can modify, like a step or iges file.

Try these links to the stl files:

The small screw holes for the motor are not in the model, they were drilled (I did not have the exact locations until the motor came in). I recommend printing 100% solid parts (with supports).

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Maybe that could help … I asked APS some questions about there 70160 motor, which look exactly like this one.
image
This is the answer :
image

They said you need minimum 20S battery

They couldn’t tell me what propeller they used, the client who asked for the test took it back … and the test was done in a tank

Thanks a million! Motor ordered and new powersupply coming for 3d printer - be a while but I’ll keep you updated! Appreciate it!

20S equals 80volts when charged,
This can KILL you in wet conditions

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FYI, the holes in the front of the motor mount part are for M4 inserts (insert with soldering iron): McMaster-Carr
Those holes should be qualified to 5mm dia. prior to insertion.

This certainly appears to be identical to the MP70131 100kV unit I am using.

You do not need 24 cells unless you also need 5.3kW.

Although I am foiling on 12 cells (I am 145 lbs, although it has foiled with up to 180 lbs), when I build a new pack it will be 13s or 14s cells. I want more power margin in headwinds, chop, and low battery. My system currently requires about 58 amps to get up on the foil (2.8kW), and 40-45 amps to maintain speed once foiling (1.8kW). This is with a 2-blade, 7" x 10" thin APC E type model airplane prop (cut down from 16"). I expect continued prop optimization will further reduce power requirements.
image

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Just getting my build together. This is how I’m attaching to the mast. Have to say I’m a bit nervous about attaching via a thin ring. Hope to do some tests in a tank soon.

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Prop update:

Now that I can log rpm, I see this prop is not letting the motor get up to max power output speed (~50% of no-load speed, it runs at 1750 rpm but should be at least 2300 rpm under max load).

The best performing prop is now a 5.8" diameter x 8.5" pitch, cut down from a similar 14" APC thin E type prop. Still not satisfied with low battery, fresh water performance though (12 cells). Foils at 36-38 amps, 2250 rpm.

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Is that a inflatable board? Where did you purchase that?

It’s just an irocker sup that I put together a power kit for. Not planning on using it for the efoil… Just happened to be sitting there in the pic.

Hi. Same motor here but I can’t find any prop suitable. Can you share your prop files?

Tks