Yes I think it’s possible to do it (not with casting resin but in carbon fiber).
It will be more complicated to design than wings. Because the blade section, size and angle of attack changes from the center to the tip of the blade (as you can see in the picture the blade is much thicker around the center, and very thin at the tip).
So I will need to design a propeller by hand (do the calculation by hand) then make a computer model for CFD analysis (and validate it). Once I have the same result by hand and with CFD, I can optimize the propeller for our need, and finally we can test it in real water.
Does anyone know anything of the Manta 5 project? Noticed the prop is interesting, perhaps a worthy candidate for an efficiency optimised prop.
From a quick look at the construction video it looks like they’ve gone with a pretty high aspect prop, mix between multirotor and plane style.
Specs from their website: 21kph top speed, 460W pedal assist motor
Complete napkin measurement of the prop gives around 10 inch diameter and 12 inch pitch, which gives around 1200rpm at full speed, so perhaps 4S and 100kv motor. Likely the 12 inch is more like 10 or the top speed is much lower.
The average cyclist can deliver roughly 3 watts of power for every kilogram of their weight for one hour.
A top cyclist can deliver roughly 25 watts of power for every kilogram of his/her weight, but only for short periods of time (before the finish line, etc.).
