SoEFoil
WE could just use the same prop as the waterwolf
at 1000-1200 rpm I gather but not sure it would just bruise you
Or we could spec a pitch for 35 knots and run it at 600-800 because our desired top speed is or will be half that
we cannot run this propeller (beside the fact those are for boat, but with the v10p350 you can get good results…)
- bigger propeller, it will be out of water or you need a least 1m mast
- low rpm : you need a gearbox like waterwolf, we don’t like very much gearbox and there is no motor on direct drive capable of running at this rpm with the needed torque
for safety the all thing i keep up with is a weak point in the system, like the propeller pin could break easly to minimise injury
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No, I get it, you are banging on about safety. But the topic of this discussion is a duct solution for the 80100 outrunner motor. The Durajet quite simply is not that solution.
The Waterwolf prop is the torqeedo prop. They just spin it at a higher RPM to get a faster speed.
To use the prop for efoil you would first need to cut it down (Alexandre explained why), and then spin it faster to get to the desired foil speed.
The ideal prop size is around 140mm (this allows foiling higher up while giving good power and speed), this is well proven by the commercial companies (FR started at around 180mm and went down to 140mm).
Now onto the actual topic. @Felixfoiler you will need a duct with around 6 struts to provide a sturdy structure and prevent vibration. The easiest way to do this would be to build the struts (5mm width) into the rear section of the mast clamp and then have the actual duct attach to the struts.
Thank you but I’m so frustrated how my prop duct turned out. Yesterday I tested it and I had lots of vibrations then It cam off and I tried without the prop and yes I flew for the first time on my foil.
That said i mounted it again on and I tired it again in the pool. To describe the feeling:
With duct: Slow lots of vibrations. It’s like cycling and breaking at the same time
Without duct: Free silent no vibrations fast.
BUT MY PERANTS IGNOR EVERY ARGUMENT TO DRIVE WITOUT IT. IM VERY CLOSE TO THROW AWAY MY PROJECT.
I am very frustrated now as my parents don’t listen to me. I know it’s dangerous and it can kill you but a car can too.
What size prop and duct are you using?
Hi,
I had similar problems on some prototypes with board bottom full of edges, screws heads etc it was the board behaviour was chaotic while touching the water.
i took your picture and circled in green the parts that may create some disturbance in your duct system.
Can you try to cut them at minimum length and use flat head screws ?
Also the wood part need to be given a more dynamic shape, or just replace it with a longer 3d printed part with water drop shape. And get those 2 top screws pass inside this part and also inside the fuselage.
No I was saying as a responsible adult, YOU, I mean, NEver encourage someone to avoid ducting a blender near their feet and toes…that is NOT banging on about safety that is saying DO NOT under any circumstances ENCOURAGE dangerous and irresponsible behaviour…
Those are some absolutely huge differences in a about a TEN word sentence that is one giant misleading distorted LIE.
The above is why I will stop responding to the garbage that comes out of your mouth and ignore how you attempt to say “so you are saying”…then you attempt to fill up the screen with outright lies or misrepresentations…
anywaty go cut off your own body parts for all I care, have fun with that…now back to the adult conversations 
Take care Jezza Thank you for interfering in a convo unrelated to you essentially where you contributed nothing but criminally irresponsible advice
WTG?
listen Jezza you are getting an outboard motor propeller and sticking it to an electric motor
THAT IS EXACTLY WHT THE DURAJET DOES!
with an increase in final speed for God 's sake
ARe you being deliberately obtuse?
anyway WE done for realz
Alexadre that is a great idea, the break away one i mean…
The Canadian governement, and granted we live in a nanny bubble wrap state where the biggest fear is people will get their feelings hurt…but they outright banned them with a $500 fine if you are caught…Prototype or not…
To me the durajet is proven, comparitively cost effective just too big
Ducted propellers produce far more thrust out of the hole, kinda ideal for foiling…
I have a cordless drill with an RPM close to the desing spec of the torqueedo prop and it litterally just pushes my hand away at fulls peed
(yes it was kinda scary but i started off very slow and when I didnt hurt my hand kept speeding it up…anything for safety :P:P
Hi Felix
I have seen people post links for kort nozzles and VeFoil i believe tried them.
I am very sorry if I gave you the sense giving up was okay but honestly I use to windsurf and in the learning stage the last thing you are thinking about is your safety out of shear frustration.
The biggest problem I had with your design at first view is it is a metal propeller and doctors never perform an amputation with plastic saws, or knives…so the exact same thing in plastic with well rounded edges takes the risk way down
these damn electric motors are deceptively small but imagine getting into the water with your lawn mower which produces 3-5 hp
kids have their ankles cut off all the time from rolling over their own foot
waterwolf uses a standard prop and their duct is not 100% safe so making this sport 100.00000% safe is not my goal
My goal is at the minimum make the propeller out of something that will not easily cut bone or ligaments…so nylon WITH rounded edges even as a “learning” version might be worth it
I am a parent too
We skydive in this family, surf in the ocean and so on…nothing is 100% safe but if it looks like a blender at least make it out of plastic…
But what should I do now ? In stuck and I don’t want to get again such a pipe
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are your parents ok with a 3D printed plastic propeller with big round edges ?
(Yes those aluminium outboard propellers are very dangerous )
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Should I go again for a 3d printed one?
Printed blades around the motor should work right? And then it should be easy to mount a guard around it
Well, I found a similar solution:
Support:
Attachment Spacer:
And the good old 200KG
Does it add drag? For sure.
Is the power still enough to foil? had the power limited to 3kW and never saw more than 2.6kW in the log. Still was able to get out of the water easily but still I need some training to foil, so all I can tell is that 2.6kW are enough for 28km/h on the water (not flying).
How big is the difference to no duct? I don’t know, this is the first iteration, since it works, I wont change it.
Why is it so long?
Spoiler
Thats what she said 
Reaching into the prop from behind might hurt, but getting caught from the inlet will definitely cut something off, in my opinion a short duct is much worse than a open prop.
That happend after I left the foil in the car (ok, it was never made to last, since it is PLA). So I removed the support and tested how good the KG200 holds up with the single support (2x M6).
Works as good as with support.
So for you to improve your duct, make an adapter from the fuselage which supports the duct in a bigger area and round the edges of the duct.
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P Kay…your assumptions are where the problem lies!
Not at any stage in this thread have I ever encouraged anyone not to use a duct! Read through the whole thread and you will see that!
I have in fact simply stated:
- An open prop is more efficient for our uses (that does not mean I am encouraging it).
- The Durajet is not more efficient for our uses (regardless of the graphs as they used the incorrect open prop).
- An open prop is not banned on small leisure craft in Canada (which is the category an e-foil fits into)
With that in mind, it seems you are assuming I am promoting using a open prop, which is not my fault.
Telling me I speak garbage and I am being obtuse is rich coming from someone making assumptions and not doing thorough enough research.
Where is the evidence to back up this claim? What have they banned? Please back this up with actual legislation!
Now if you can’t be civil, go find a “safe space” where you can cool down.
Peace out bish…
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@Felixfoiler what pipe did you use for the first duct?
Send me measurements of your prop and the duct. I will draw up a 3D model for you with the rear mast section that should help you out.
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Thank you Bender. I know my ideas are not perfect but I would feel awful if Felix got a slice never mind worse 
Thank you Jezza that is what I was hoping for. Much appreciated.
Last time I checked it is not required to prove facts on a forum (never mind to the engineering or saftey challenged)
Google it yourself
and you have hardly been civil!