ORIGINAL: coolman1985
I am somewhat new to RC helicopter, so this might seem a bit ambushes.
I would like to design my own propeller, however while I am vary good at math and a fair sculptor (mostly carbon fiber). I cannot find sufficient equations on the internet to complete my design. I know that the angle of the blade changes as the radius changes from the hub moving outward, keeping the pitch constant. The equation I am using,
Angle = Tan^-1(pitch / (2*pi *r)) where 2*pi*r = the circumference. My question is, how do I know what pitch to use? This should be based on the rpm of the engine right? Do you have formula for it? Even recommending a book would be vary helpful. Any response is greatly appreciated, thank you for taking the time to read this.
ambushes? No ambitious ... probably.
vary .. very?
Anyway ... since you posted in the heli forum and not the airplane forum ... I assume you are referring to the rotor blades (main and/or tail) ... what you called a propeller. Do you need fixed pitch blades (lift determined by RPM changes) or do you need Collective pitch blades (blade AOA determines lift as RPM remains constant).
With fixed pitch helis ... the blades do seem to take a likeness to airplane propellors, however, collective pitch blades are generally the same shape (pitch wise) from root to tip.
So either you are in the wrong forum or your math just got very simple.
Good Luck,
d.tipton