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 
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
Thanks
I love your forum
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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
Thanks
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.
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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?
Thanks.
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
I don’t want to underestimate the risks involved in this sport but to put things into perspective my crash test dummy and chief R & D guy is my 12 year old son followed closely by my 15 year old daughter. Both are now accomplished efoilers and are the envy of their mates. I come a close third at 47 years old. I insist on helmets and impact jackets, the rest is just up to them.
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So what’s your setup then and you don’t have a duct right.
But what I want to explain is:
Do you want to get hit at 5000rpm from an aluminium prop with a 7ps motor. I think not and I think that the helmet would not sustain this impact
However thanks for your feedback
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i took me a few pinched fingers before i tried something better :
exact order is:
Remove the alu piece where the wires exit,
Remove the 4 radial screws that hold the part where the big bearing fits
Remove the snap-ring on the shaft and the washer below.
That should allow you to extract the stator.
mis-using a clamp like that work smooth,
Before i was using 2 sharpies to push it from the bottom (you can see that in my movie), but that’s not safe at all…
Then i started just threading a thin rope from the open side between the windings, and making it come back kind of on the opposite side. Holding the rotor between my feets and pulling on the rope… not much better.
Finally once the stator is out, you can get the shaft out of the rotor after unscrewing the 2 set screws. My original shaft was stuck, so I had to heat up the rotor around it with a torch to make it expand and get the shaft out.
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Thanks I will do that I hope my fingers don’t get crushed I wearing gloves. I had a different outrunner before (smaller) and I crushed my little finger between it when I closed the motor --> ouch that did hurt
My project is getting forward
http://premier-marine.com/durajet-jet.php
Felix, Let me first say I am beyond impressed with your thihking.
All it will take is one chewed up beach goer to cause punitive legislation.
the above link avoids the need to reinvent the wheel and it provides VAST increases in efficiency compared to a “jet” drive
I am a former R&D engineer with several patents in my name and prior art is the issue with all this stuff
Lastly, WATER gets into everything, so the ultimate solution is a gear case just like in the 50-70 year proven design of the standard OUTBOARD 
In Canada we dont even have a choice!
the link below is 100% safe and is more efficient:
I heard that you are not allowed to have a free propeller In the water. Last week I read in the news the a 19 years old girl got killed from a normal 50ps boat. (She was free diving).
What I want to say with this story is that it is necessary to have such a guard around the prop.
But I cant really engineer anything because I have some tools and a 3d printer and with that I’m building a e-foil. So I need a way how to build such a prop guard.
Thanks I’m really impressed by the jet outboarders and after my efoil build I want to build a jet sea scooter.
My parents are all about safety and they are my sponsors so I need to do what they say to me.
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What is that more efficient than?
@Mat i did it tried it with a pulley and it worked fine
and my rotor looks damaged I think I got a used one🤨
