Well I've got my electrics ready to fly and I've been doing some run times trials and also measuring the Amps and Watts that the motors are pulling. I've got a question reguarding the length and pitch of a prop. For an example, and I'm not sure there are even props this size and pitch..but lets just say there are, I'm running a 8 x 5 prop and i'm pulling 24amps. Would a 9 x 4 prop be just about the same since I'd be cutting back on pitch but lengthening it? I'm just trying to understand what is happening. I know higher pitch like a 8 x 6 would pull more amps and a 9 x 6 would pull more amps than a 8 x 6. Is there a general rule here?
Thanks for all your comments.
Palmer

There is a rule but it's not very simple.

You can calculate the power required by the propeller. For a given speed it increases directly with the pitch but goes up by the 4th power of the diameter. So generally a small change in diameter makes a lot more difference than a small change in pitch. Of course it then gets confusing because the larger prop runs slower and that reduces the power required to some extent.

I bet that was a lot more than you wanted to know .

Steve