Gathered a little data this evening comparing my 3d printed rotor with foam blades to a 5x4x3 prop, same motor:
At low throttle, the cyclo looks promising, but it oddly tapers off and seems to level out at higher throttle/RPM. This doesn't follow any rules of aerodynamic rotor performance and I think I know why. I'll come back to this later...
Now this plot gives us a better idea of efficiency. It's easy to see that my cyclo is producing less thrust for the same power. Not really surprised, since I spent no time optimizing it haha.
Power loading tells us how much power it takes to generate a given thrust. We want to maximize thrust and minimize power. So larger numbers is better here, and you can see my cyclo falls short compared to the prop. But there's that weird dip at 30% throttle again, similar to the thrust vs. throttle plot that levels off past 30% throttle.
My theory is that my fragile foam blades are bending chord-wise due to the centrifugal force and curvilinear flow (below), leading to that major drop off in performance at higher RPM. I've got super-slo-mo video to prove that's what's happening, and it would make sense that the blades bending to 'adhere' to the flow would lead to less net angle of attack and less thrust. The force that goes into bending the blades translates through the rotor and to the motor and gives nearly the same power draw at the lower angle of attack.
Anyways, I'm sick of printing and assembling parts. This rotor gets the 'Good Enough' seal of approval to throw it on the airplane. Maybe I'll find the time one day to optimize this thing...