Many thanks for the info, I would also like to build a jet propulsion, since I have already built one with propeller, I would be glad if you could send me the STL files by email to koni@gmx.net.
thanks koni
PS: we are all on the find out what works, the more the better 
400A ESC, waterproof and watercooled, that’s important for the first tests, I’m sure you’ll get water inside for different reasons, I’m working with 8s. I think your prop is well designed, but try other more resistant material.
About a jet propulsion… I have been followiing a guy called Mark for almost 2 years now, look where he is going to…
Hey man great design. Im doing some research into propulsion of this type and would love to take a look at your model.
Are the files still available? I prefer IGES or STEP if possible.
Many thanks!
Hi. You need to contact Mark directly on his YouTube channel, but I think that he will take the business route so I doubt that he will give to you any STL. Now if you look at thingiverse there are similar set-ups to download from.
Hey Folks,
I have started to built my own version of an Jet powered eFoil, at the moment i am trying to figure out what kind of design and materials will work out best for me.
Does anyone of you have experience with the sealing of the shaft with jet propulsion units? And maybe can recommend a design or suitable seals for such high rpm (max 20 000 rpm)
@virus: How did you sealed the shaft of your Direct drive Jet unit?
Best regards!
Boris
Very nice looking components… Any chance I could take a look at your STL files as well? I’m thinking of going the jet route also as I want to surf with it and I’m thinking the jet will have less drag than a prop.
Cheers!
How about to get more thrust from a jet use an air pump to pump air through a hose down the mast and out into the impeller? Something like this maybe? 50w, 12v and 300lpm of air flow. We could even use the air flow to cool the esc and batteries before going down the mast. Maybe connect the air pump to an esc as well and optimise the air flow for the jet depending on rpm etc.
The thrust from jets is the “exhaust” mass moving in one direction and the body in the opposite direction. The density of air being lower than water means it would have to be many times faster to have the same effect. Water is a great, heavy material to be used for thrust.
Had the same idea in mind, but i will try it without additional air first, and then compare the thrust with and without added air.
My simplistic thought process is that air being compressible unlike water will get compressed as it goes through the impeller and so as it goes out the jet it will want to expand giving more thrust. Also the air and water mix being compressible will allow the impeller to get up to speed faster with less torque. Maybe there is an optimal amount of air to give more power to an underwater jet?
@surfsup, I like the idea of pumping air down to improve jet efficiency, I suggested that before too here. Jet dives run more efficient with a water/air mix, all jetskis benefit from this as the intake is so close to surface with lots of air bubbles. We don’t have that 4ft below. You should build a prototype, I am really curious how this would help 
Great minds think alike huh lol. I’d love to do a prototype to test but I think others will beat me to it. I have bruno’s magical 100kv inrunner so will be testing that first with a prop but I’ll probably be slow to even get that done as I have very little time at the moment. Bruno told me the motor was 85amp, 90v which sounded like it might work but I see he has told you its 65amp, 120v. I wonder which it actually is? I’m losing faith in this motor working as I’d hoped so will try a jet if it fails…
Hi
I had a quick try with this and did not see any improvements in thrust
yes it allows the motor to spin up.
might need to reduce the outlet diameter to compress the air more???
and also I did not pump the air down I allowed the air to be drawn down by Venturi effect.
just a hose down and ending just before the water inlet
Interesting. Thanks for sharing your test. Could it have sucked too much air?
Hi
I had a valve to throttle the amount of air but felt that the out let nozzle was too big to compress the air
to give that explosion of energy as it exited.
I was running a 5mm internal bore silicone pipe.
the same size as I use for cooling the ESC
I might try again with a different outlet nozzle will need to print one
Thanks Nick