I have designed this for a school project of my son (Fip NWA, Fachinterne Prüfung NaturWissenschaftlichesArbeiten).

For this to work in OpenSCAD, you need the NACA Airfoils library from Parkinbot:
https://www.thingiverse.com/thing:898554 Many thanks for this library.

You can print it for 2 to 6 rotor blades, and configure also different angles. The rotor blades are mounted with a bayonet joint, and all parts are designed to print without support.

In our case we can say, that the transmission with the belt drive is not needed, respectively has too much friction loss. So take the direct drive, and mount the rotor directly to an engine with a 2 mm shaft.

Up to now I can not say, what is the result of the experiment. How ever, find it out for your own :-)

UPDATE_1
Added an additional rotor blade with different profile, and two hubs with different angle of attack.

Notes:

I have printed the rotor blates with 5mm brim, no infill, 3 shells. They have an integrated support cube, that has to be removed after printing.

Rotor and rotor blades are printed with PLA. The other parts I have printed with ABS, all without support.