@Gobbla Nice work, It looks amazing.
You have many fantastic features in your design !
One question what is the logic behind the long propeller shaft ?
Cheers,
Al
hello theone, for me the logic behind the long propeller shaft is to decrease turbulence after aluminium pipe.
i m not using princple of ducted proppler (Kort nozzle).
I m juste protecting proppler for user. It is less efficient than kort nozzle, but efficient of ready made aluminium proppler is 30% more efficient than 3D printed proppler (tested).
@SoEFoil you right i did not make any hole in the mast. i m planning to use fiber carbon mast without hole inside. ESC is cooled with air.
Hello Gobble,
Good point turbulence / Cavitation = Reduced efficency!.
30% (TESTED) is a huge saving with a ready made prop.
As you know a Kort nozzle is not suited for high speed boats (or efoils)
What is the pitch & diameter of your propeller?
What RPM do you spin your propeller at?
Gearbox Ratio ?
I want to go the same way, but I am not sure whether a tube or a cage design will be more “effective” (sure both will create drag, the question is which one will create less, cage has less surface area but more turbulences…)
Do you know, how much power you loose by the protection/duct? (test with ampmeter with and without duct, or maybe even different ducts?)
Okay, but my question was, is it better with intact tube or better with something like that:
Okay, but in my opinion best would be to just try it in the final setup and log everything (speed, RPM and Power). So you also see the effect of the spinning propeller inside the tube…
Definitely intact tube, no doubt about that. Better if you thin your trailing edge and round a little the LE… it reduces turbulences.
Long means more drag, this goes for the motor pod as well, even though good profiles of nose and back end could improve the situation. With Efoil the problem will be that the tube won’t run horizontal, almost never. You’ve to improve this by fine tuning wings AoA, this will reduce greatly the drag loss
Do you think it would have lower drag? & improve safety just a bit ?
It may inspire some one to take the concept to the next step of hinging inwards when not in motion ???
@philgib i have made long tail to avoid turbulence before proppler.
At high speed for me it will reduce efficency of proppler.
I did not make calculation to define the best length
I would try to make much more room for the motor cable solder joints. Mine ended up about twice as thick as the cables because I had to make them waterproof. They are also very stiff.
