For who try/have tried direct drive with outrunner

I have another thought. Wondering what you think. I assume you know of the APS-70110, Water proof 70mm outrunner Alien motor that is in a Stainless Steel can. That motor seems very similar to the motor Jsonnett is building. MaxMaker and some others are using this new motor. It might be the same motor in a different can. Would you expect to see the same problem with that motor?

Hi PowerGlider,

Do you have a model of your prop? I’m looking at the 80100 motor(130kV or 80kv/7000W) or the motor you are using. The 80100 may be overkill. I don’t think I need that much power. Wondering what you prop pitch is? I don’t think you are foiling but its probably enough power to get lifted.


I can confirm, 80100 is overkill.
but after doing a full complex build for month and ending up under power, overkill is a nice option… at least it works, i just started a thread showing how i used it.
I have the 80 KV version. I use a Solas 0001-073-06P so pitch is 6 inch, and it seems appropriate. Top speed might be a bit high, but that might be just because i’m starting, and who doesn’t like a bit extra speed ?? :slight_smile:


that sounds good Mat and I agree…I’d rather have too much power. :smile:
Do you know how much torque that motor has? The power glider motor has 6.9nM which
I think is enough. Ok, look forward to seeing your posts on your set up. I’m getting close to ordering parts…and then I’ll share.

No idea about the torque… all i know is that it works… and the motor doesn’t seems to struggle too much to rotate the prop. All i can say for sure is that it doesn’t stall.

I installed a power meter to get more data when riding, but that’s a big failure as i can’t read it when riding and it doesn’t record the data…

My build is in the thread “80100 direct cooling”

Pop a gopro on and aim it at the meter :slight_smile:


Sorry, i do not have any model or STL files of the props i am using. All of them are commercially.
First model was 7 1/4 x 5", cut back to around 170mm in the old duct
2nd was the same but cut back to 137mm in new duct
3rd is 7 1/2 x 8" cut back to 137mm. I also plan to test 7 1/2 x 7" and also cut it.
All have pinion drive, the later ones i also cut the hub to adapt to the motor to make it shorter. The better quality was the Yamaha branded.
Have a look here:

You can also try the plastic Solas ones, like Mat, i did not use them but thought about.

ok thanks. I will get a few to test. What dia are you getting the most thrust out of? and which the most speed? Is the yamaha the best performing?

im using 2x 83100 watercooled outruners… and you say your single is overkill haha

they are rated for the same power as the 80100 so i think you have the right number… if you’re building a family foil :slight_smile:

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Maybe interesting:
he uses the same motor, but submersed in oil.
According to his tests he gets about 120lbs of static thrust @12S 3,5kW

The design is a bit bulky (imho), but I guess the glass tube saves much hassle of isolating or epoxying the motor.
Also he has a nice prop design, optimized for 2k RPM no duct…
The CAD files are attached for solid works.
Also there is a 3D-PDF to get an impression (if you don’t have access to solid works).


wow, thanks for sharing Giga. This is right where I am…
I have an encapsulant coming for motor but also looking at
oil filing a small tube which could also be pumped to cool the
esc. Either way should work but want to keep it simple.

Finally, I have made quite a bit of progress since my last post. My foil is working OK. Sometimes it even still works at the end of my test ride. I am able to foil on my knees for almost a minute before falling off.

It is now ready for testing…

The big question is whether there will be enough heat dissipation through housing…


Today I manged to get to a standing position on the foil. I went for at least a minute.Most of that minute was slower than on foil speed. I am running a dry pod 83100 out runner, actually I have 10 ml of mineral oil in it. I have had no problems with motor heat.
I believe I do have a problem with my ESC getting to warm. When I fall after running hard for a few minutes. My safety lanyard kills the power to the ESC. The ESC will not restart until a couple minutes pass.

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Nice setup! How have you secured the battery box to the board?

The battery box, has 4 nylon 1/4-20, 3/4" long bolts passing through it. I have automobile gasket sealer on the heads of those nylon bolts. Those nylon bolts screw in to steel 1/4"-20 coupling nuts on the out side of the box. The coupling nuts recess in to the urethane foam surfboard. Then I screwed steel all-thread into the coupling nuts with big washers and nuts. Its a little ugly but it has never given me any problems.

Here is my battery box. On my second day learning to ride it after about 30 mins I got into some weeds. I turned the board upside down to clean the weeds off the propeller. At that point one of my low voltage battery alarms started going off. So I slowly powered back to shore. When I got to shore the other battery alarm was going off. Turns out I had about a cup of water in the box, when I turned the board over the water got everywhere. Fortunately after sitting in the sun all day and shot with a leaf blower everything started working again.
Now I have added a way to add some air pressure inside the box before I leave. You can tell right away if you have a leak.

I am really curios how things work out with your motor selection. When I first heard about that motor I thought that looks a like the size of the motor Lift was using for their E-foil. I recall thinking that If you drove it with 14S ( thats what I heard Lift uses) it would put out 6500 watts ( thats what I heard Lift uses).

In a effort to get my ESC to run a little cooler I changed from a 6" pitch prop to a 5". When I went out to test it, the board was behaving strange. Vibration, did not want to lift off even at faster speed, sluggish. Within about 30 seconds the motor cut out, I was on my knees and was thrown over the nose of the board, jammed 2 of my fingers into the front of the board. Long story short, I had picked up a bunch of weeds on my prop and foil. That destroyed my 200 amp Flier ESC.