Another Jet Propulsion Try


Ceramic seals, viton seals I tried both.
I think the angle respect of board is a little open. wing is low exposed.
your weigh and electronics, batteries on back, high ratio wing,I think you don´t lift with this setup.


Hey @virus, I think you are right regarding the angle of attack, but i wonder how it turned out so big in the end, because i copied the board geometry from a commercial Foil SUP…
Now i will have a look where i can adapt the angle in this system without to much work :slight_smile:


Add a wedge underneath the mast foot?


Fast option is work in the wing, remove that wing and work in other with better angle, ok?


Unfortunately it is not possible because of the inbuilt connector, If i would do so i would have to add a about 4-5cm thick “interface block”

i think that’s the way to go till i found the perfect setting for me :+1:


Mark’s remarkable progress


Your ptich angle of the board foil looks wrong. Once foiling the front wing will have approx 2-4°. So your board will stand in the air at a very steep angle and not be parralel to the surface. So the ride gets wron impression and it is hard to stay at constant height. I would decrease the angle between your foil fuselage and board… . Or maybe it`s optical illusion on this foto?.


you must decrease the angle at the mastplate where it is fixed to the board. You can as well do an angle at mast/fuselage connection, to get it more parallel to the board. I would advice max. 5° difference… However this will shift your CG of the whole system a bit forward… Could work. Usually your back foot us just 1-3inches behind the mast…if your decrease angle at fuselage mast connection then you will have to stand a bit further back…
Anyway the RL Foil will be fast with your 100kg total weight. Don´t expect flying with less than 13knots…


Hey Folks,
regarding the angle: it turned out that there were a few things that made it look that big:
the first reason was the big cut-outs i made for the inner parts such as battery box, and the wood ribs which support the carbon tubing for connecting the two parts, As i glued the parts together in the the vacuumbag the board bend up on this spots so the rocker of the board increased.
I already managed to bring in back in the desired shape.

As i said in the beginning, i took the board shape from a commercial available foil board so usually that should work fine :slight_smile:

Unfortunately i felt ill last week and my workshop is to cold to continue building when I am in this condition, otherwise the board would be already tested on the beautiful Wörthersee


take that:

for electric motors up to 4kw…


My gutt says 49mm jet is just too little Gogetta. Seems Virus has a proven size and 56-64mm are likely sizes that will work best for direct drive jets… But you can buy just their impeller for $23 from them and test in a tube, shaft and coupler to your motor?


RL mast is ok for 8Y cables with some space for sensor cables or whatever. But the wing is for kitefoil so I would like to know how it works for efoiling. René has flat one for efoiling now and guys are working on same as you have but bigger - cca 850mm wide for efoiling.


I take it you guys have seen this site for jet drives, (sorry just seen earlier you mentioned it was a MHz prop)


Hello Boris,
are you from the Wörthersee? I am living here. I am working on a 60 jet. Maybe we can meet ?


Hey Toto,
yes I am living in Klagenfurt, of course we can meet if you want!


Lot of guys building with various size impellers it seems. So far I have chatted with guys using 51mm, 56mm, 60mm, 64mm, 70mm, 80mm impellers. Based on my own testing and the results of others the sweet spot is between 56 - 64mm with direct drive.

Virus has set the benchmark that 56mm works well, and the larger the impeller gets the less they seem to perform with the lack of torque from direct drive.

Here is a free impeller design software: Jet Propulsion?


Did you find one seal better than the other? are you getting water into the motor housing?


I did not had the time to test the board yet. I should be able to finish it the next week, and then i will report :slight_smile:

Best regards


Please do not spam the whole thread with this build, the performance is not good enough to power a hydrofoil with it…


What happened with your Torqeedo foil? Is it running yet?