I bought a 13.25 x 17 pitch three blade boat propeller for my mercury 75 hp outboard last year from Hexautoparts.com. So far I am pleased as it improves acceleration and top speed.
But most of my friends are four blade fans.They told me a four blade prop of the same pitch will run at less rpms than the three blade because of the greater efficiency.
4 blade propeller or 3 blade propeller,which blade prop do you like better?
I would like to hear your opinions.

Wouldn't the diameter, not just the pitch, have an effect as well? I think the torque of the engine and the weight / drag of the boat would come in to play too.

I would guess the 8 blades on the Spark is optimum for the drone. Less and it would spin wildly out of control.

HI, thanks for the inquiry. We're hoping that you could get the best feedback that you may need from our valued DJI Forum members. For a friendly reminder, please be cautious on using third-party accessories as it may cause the performance of your drone. We do appreciate your understanding.

Boat propeller talking on a drone board?
75 hp boat engine?
Didn't you mix something?