80100 Duct for Safety

Hi guys,
so i want to build a safe E-foil and i was wondering if anyone else designed a duct for the 80100 motor?

as you can see it will be a pain to 3d print. Do you guys have a idea how to make this hydrodynamic and stable?

I tried my best !



That’s why i didn’t try to put one on mine…
I’m afraid in your current configuration, you won’t be able to get it stiff enough to avoid the propeller to touch it.

One thing you can try is to make a custom propeller that fits around the rotor, it will end up much closer to the fixed part and you won’t need the long “arms”…

True i will try that!
Is your foil still flying? I was riding a lift foil 2 days ago how would you compare yours to the lift foil.

Can I cut the shaft where you used a titanium shaft(I’m not using it in saltwater)
Should I still coat the windings?


It’s still flying… i mean didn’t took on fire yet :slight_smile: if the wind is nice the weekend, i want to try a faster wing.
I’m sure the lift one is more “mature”, probably more stable and for sure more efficient :slight_smile:

Cut shaft should work fine… but you’ll have probably have to cut twice to preserve the snap ring groove a the right place.

I would still coat the winding to be safe as it protects in case a foreign object enters the motor (sand, small rocks, … )

Is your 80100 motor still in shape and where do you get the bearings from?
Could you give me your mast clamp .step files?

And ok I will coat the winding of the motor. What if I print a housing for the motor would it overheat? Why does none use the new Waterproof inrunner from alienpowersystems?

yes, motor is all good… only issue from time to time with the magnets rusting a bit.
my bearing are from ebay, from UK…

For the mast clamp files: https://a360.co/2OjDz
It’s made for the liquid force mast, if you have a different mast, i think it has been adapted to the slingshot mast somewhere on the forum, other than that, you’ll have to modify it.

With a housing you’ll have to make sure it’s waterproof (more complexity) and the diameter will start to be quite big. Also,inrunner with housing are ok as you can cool down the stator by having it in contact with the housing, but as for a outrunner you’ll have a gap, so cooling will be difficult.

If you want to run it dry, inrunner is for sure a better option. I think the waterproof one from Alien was done on the request of someone from this forum… so it must have been tested… @PowerGlider, isn’t it yours?

HM so the problem is I need a duct otherwise I won’t be allowed to drive my foil, because it’s too “dangerous” (I’m 16). Second problem: I have a 3ps outboard aluminium prop and I really want to use it so I think I will need something like the long arms. I need to figure it out my own way (I think). I will let you know if I have a solution to this problem.

Thanks for your detailed answers!

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Open direct watercooled outrunners i do.:smiley:

I don’t know what you mean

could this be it?

could be stable enough and perhaps it doesnt have lots of friction?

perhaps i would make the white “arms” out of aluminium and screw them onto the duct that could be the second option :wink:

Hi @Felixfoiler, great that you are working on adding a duct to the 80100. How about designing a prop that sits directly in the spinning can of the outrunner. This would allow a more stable duckt mount. I tried something like that but my motor was too small back then, info here For who try/have tried direct drive with outrunner - #3 by pacificmeister - Propulsion System (Motor, Gears) - FOIL.zone. With a duckt it could look like that

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Thanks but as you can see in my other topic I got a 3ps aluminium outboard prop which makes it impossible to mount it onto the motor but perhaps if no other solution comes into my mind I will take your advise and mount the prop onto the 80100 motor

I love your forum :wink:

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@pacificmeister could you share this nice 3d model with me. I would need it for fusion 360 so in a .step file


Sure, here is the Fusion 360 design: Fusion But you need to modify it for your 80100 motor, this one was for a smaller outrunner.


This is what @benha showed us 2 weeks ago. The machine time must be quite long.

The machining time for that prop was about 15 hrs. My mill is a converted Bridgeport so it’s not super rigid and the spindle tops out around 3K RPM. With a “real” mill you should be able to fab one of those things in 3-4 hours. The bulk of the time is in the ball-mill profiling which I did at a pretty small step size so it wouldn’t take as much hand finishing to get the ridges smoothed out. You could cut it down considerably if you were willing to do more sanding.

The “real” challenge isn’t the fabrication as much as the design. Creating a model for a proper, bespoke propeller isn’t straightforward, and the purpose built packages that do it (ie: PropCAD) are outrageously expensive for a hobby application.

On the question of nozzle design, for my project I did a very lightweight 3D print of the part I wanted in multiple pieces. Then I glued them together and added sprues. The whole thing was then invested in ceramic slurry and fused silica, burned out, and cast in aluminum. Allows you to use the ease of 3DP to create a part with the strength of cast aluminum.

Nozzle design is its own highly scientific affair. A proper nozzle has a specific airfoil shape and maps tightly to the propeller intended to be used with it.

Solid data is hard to find since some of this stuff is proprietary to commercial organizations, but there are academic papers out there you can find on the Kaplan propeller and Kort nozzle design. Per my earlier thread that pairing is more suited to high thrust, low speed applications so may not be ideal for the eFoil crowd, but it could be a starting point for those interested in experimenting.

as i got my 80100 motor today i need some help from you guys. @Mat opened the motor. I need to do that too because i want to short the shaft. How should i open it that i dont damage my fingers and the rotor?


Guys IMHO way too much emphasis is being placed on prop guards. The real danger is falling on the mast or wing. Wear an impact jacket and a helmet until you are confident on your board and then accept the risks that are associated with the sport. Otherwise choose a sport more in line with your comfort factor.

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Thanks for that answer I looked around for something like this to tell my parents