How much thrust do we actualy need?


#21

The same 56mm impeller.
400A ESC Flier, waterproof and water cooled.
motors: leopard, sss motor and tp power, tp power can support more amp.
exit nozzle ok


#22

You motors are all 56mm diameter?


#23

jet system 56mm but my idea is try the same gearbox diameter in open prop 30mm, next tests


#24

Wow, cool 30mm propeller is getting small, interested to see how it works
I’m a little confused though, you will use 56mm motor, with a gearbox, and a 30mm open prop?
Why the open prop? They are very dangerous


#25

when I say open prop it means propulsion propeller, jet is ducted propulsion.
My propeller with gearbox is 120mm, you can see in my videos on youtube, in my jet I’m using 56mm impeller direct do you understand? 30mm is the diameter motor brushless.
If I first made an impeller jet it was because the propeller is dangerous.
I think the ducted propeller ( bigger with gearbox) is still dangerous


#26

Ok I get it now, thanks Virus!


#27

You jet system is 56mm impeller, but what is the outlet diameter of your jet nozzle. It tapers in… have you tried making this larger or smaller for more thrust? We found that if your not using the jet near the surface to mix with air the nozzle outlet hole can be a little larger than normal and you get more thrust underwater.


#28

ok but the potential energy is not the same with bigger hole


#29

exit nozzle looks to be about 47mm


#30

We just redesigned our nozzle so we can easily change the exit hole to test various diameters from 37.5mm - 52.5mm (from to small, to too large, and find the sweet spot).

From my experience, the smaller the nozzle exit diameter the less low-end thrust, but a higher top end speed. But it nozzle is too large then you lose thrust also, there is a fine line, really the fine details will be more personal preference for each persons riding style and skill level to some extent.


#31

Hello Everybody

Today I have done some thrust test of my system

Battery: 8s
Esc: hobbywing 130A
Motor: SSS, 500kv
Reduction: Neutgard 1:5
Propeller: solas 7.25 x 6"

And tha’s my recorded data:

image

Could you please tell me if, following your experience, the recorind are enough to foil?

Thank you very much