Interested in building an efoil. Looks like a lot of tinkering designs are around.
I wondered if anybody here has an idea on how efficient those props are? It seems to me that electrical knowledge is abundant, but i am not sure if there is a lot of knowledge on fluid dynamics.
Where do you get your propdesigns?
Welcome Antonm,
I see that this is your first post. Welcome ++
Yes lots of tinkering happens with some good results… some times not so good. 
Fluid dynamics is a advance subject that is above my ability… If you have knowledge of advanced fluid dynamics please share with the group your designs Please, Please Please !!!.. over time a lot of people come & promise great efficiency propellers but then …Nothing . Pacificmeister Build Info and CAD Sources - Builds - FOIL.zone Is a good place to start. The design works.
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Eat.
Sweep.
3d-Print.
Repeat.
…thats the great thing about 3d-printing. In my opinion the three main attributes are power, efficiency and stability. First it was pretty easy to achive always just two of them, but with my last (8th) version I think i achived all three traits.
I know this isn’t a professional comment but it’s one way to approach the task 
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I think those 7.1/4 diameter prop with 7 pitch are for 8 hp outboards that can do 25kmh with 2 persons, a boat, the motor itself. That is about 300kg? With a hull that will displace a lot of water.
Can 't we use a really small prop of about 8 or 10 cm ? Maybe there is some slip when getting up. But once up, maybe it will take less power to foil. There is much less power needed to foil instead of a whole boat.
I think I will use the 80100 prop 3d file and shrink it by 40 % and just try to see what will happen
For such small Prop you will need much higher rpm
The bigger the prop, the lower the rpm and power you will need.
The smaller the prop, the higher the rpm and more power.
I have a 110mm cleaver prop that I still need to put on a motor. But it will need about 10000rpm and around 8kw of power. But it should get the foil up to around 60kph with the right wing.
i think you can get close to 60 without a wing
You can with the right motor 
It’s the same prop that the guys used on the torpedo surf build and they got to 55kph.
I know at the time i asked him about the setup and I choose the same gearbox
The 195kv motor might be powerful enough to use with this prop… Might have to get one…
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55kph! That is quick. Not sure I would have the balls to be honest.
If esurfers can do it, efoilers should as well with a bit of help: foot hooks, a leash attached to the board nose, … and a hydrofoil stable and tolerant at those speeds like the Chubanga v2… eSurfs have an advantage at 60kmph: they don’t stall from 70cm above the water surface so it is less painful to fall. 
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You definitely don’t want the board attached to you at that speed! I want the foil to go in a very different direction to me if I fall at 55kph.
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Foot hooks are not footstraps. They let your feet go as soon as your heels leave the board… Usually, only the front foot hook is used like that you can position your rear foot wherever you want on the board. It provides a better board control (therefore confidence) at high speed and opens slightly under load.
NSI and Slingshot make the best ones.
Yeah I know what they are, but I still wouldn’t use them on an efoil. I’d only use them on a board of pump.
Sehr schön
Gruss Frank
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