Potatonator sizing advice?

[prjwebb]

I guess it focuses the release to that point of the tip, i dunno. Fin design is beyond me!

[iggy]

It actually does, it has to do with cavitation

[FW - Fan]

Just playing devils advocate but...if it is necessary then why do all of the other fins out there...all of which dont have that point..not cavitate? I just think sometimes there are features like this added which may ultimately be neutral but dont actually do anything. I know Stretch takes the technical side of things very very seriously..he is a genius in my book but I think sometimes the theory doesnt translate into function...

[iggy]

Did my thesis many many years ago on Cavitation in centrifugal pumps. Foil geometry plays a crucial role on this phenomena.You will feel it more during turns than anything else where the fluid changes direction. You'll be surprised how much the efficiency of a pump varies by applying subtle changes.
Would it be noticeable for the mortal people like us?? maybe not, but it occurs. Is it aesthetic or functional? who knows.