Propulsion System - Motors, Gears, etc

This is funny:
Max Amps:

I want to use the 220A of course.
Just a minute, 0.0895 Ohms - oh no, that makes 220A * 220A * 0.0895 = 4331 Watt of ohmic powerlosses. That will not work for more than 10 seconds.
So i have to go back to 50V 80A. 80 * 80 * 0.0895 = 572W
So i can put in 4000W, getting 3438W (or less) out.
An outrunner has half the resistance and thereby half of the ohmic powerloss, 40% less area for induced drag and wheighs less than the half. And it can be cooled much better. It also has less than half of the length.


Super interesting. I think it reads on the ad mp105 posted that diameter is 56mm ?

Here is the inside with the bearing

Got version 3 of my MHz jet connect.


Looks great! Will you share the 3d model?

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Here’s the 3d model of the jet connector and the motor mount (56104 in 56.5/60mm aluminum tube):


Link doesn’t work for me?

Very Nice job @Kappertz

Unfortunately I can not open it via Inventor 2019. What do I wrong?

Hello everyone,

new to this forum. Have been reading posts on forum for some time now and I am thinking about building e-foil.

I came across following motor:

Outrunner with stator and rotor magnets coated in epoxy.
I looks like great motor for e-foil from that point of view, but on the other hand is probably not strong enough to generate enough trust for foiling.

What do you guys think?

Hope I am posting in correct topic.

It is much less rated power (from the parameters table it has 35A/10S, so it gives about 1400Wt maximum. I ordered two of these to play with them and try double motor setup with smaller props on each of them. The idea is to use low cost VESC4 (now you can find them for 53USD) so with 35A current it should be easier setup. Still in the shipment.

General question is Are two motors/props more efficient then a single one with an appropriate power. Following the general Idea in multi-copters, the efficiency goes better when using more motors (8-copter is better then quad-copter in terms of efficiency, as far as I know). I will appreciate your comments, guys from the forum.

I see 1 review on 125mm (5 blade?)prop and 25A/6S. I logged in and tried to reply the comment but i am getting error. Maybe dude knows pitch of the prop and amunt of thrust he s getting? Can some1 ask?

Friction increases with the square of the velocity so if two smaller props are running faster to produce the same thrust as a single large prop, they will be less efficient due to the higher force of friction. I run many quads and octo drones… the only reason the octos of mine are more efficient is they tend to be larger props… Quads are usually more efficient but octos are redundant and can suffer a motor failure without crashing.

My first foil build is just starting… I’m learning so much in this group. Thanks all. I’m going to try a direct drive 56114 320kv setup and may try 18S with 72 mm direct drive jet with only slight cone taper. Will see how it goes. Plan is to use an old Mercury EDF 72mm fan I have as the impeller… all metal blades and just lying there in a box… so, I’ll report back with what happens. Probably catastrophic but… fun trying.


Interesting try. Please keep us updated!

Completed all new jet propulsion system for efoils where the water intake opens and closes automatically with the throttle.

Key features:

  • Intake will not open out of the water so you cannot access the impeller when on the beach or transporting. So if someone touches the triggler the impeller is fully shielded for safety.

  • When riding and you let off on the throttle the intake closes eliminating impeller-induced drag for gliding and free riding swells without power.

See moving image below.

Super safe, extra smooth, and powerful as we take efoiling to the next level with propulsion design.


Interesting concept. How does the intake “detect” being submerged?

… and pumping ! The first serious challenger to the folding prop !


Nice gimmick. Wonder if that is working fine after sand enters the mechanism…

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As @carved said, It will need to be tested with handfuls of sand.
Even if it is only 30 degrees up and down, an apertured cylinder rotating in another apertured cylinder is generally a dirt trap in a marine environment…

It sounds like the VEfoil was designed by this forum. Maybe it should be called Efoil Builders Foil or EBF


Hy short question
has anyone tested this motor, do you think this would work?