rpm drop

[theo44]

Can someone tell me the rpm drop of a 1806 2280kv with a 3s battery once a prop is installed say a 6-3?

thanks

 

[quorneng]

theo44
Technically a brushless motor is a constant speed device. The maximum rpm it will run at depends of the voltage applied to the ESC. The motor will try to achieve the kV times battery volts (2280x12=27,000 rpm in your case). What is important is the specified max amps for the motor. This normally results in about a 15% drop from the "calculated" max rpm to about 23,000 rpm in your case.
Exceed the max amp figure by fitting a too big a prop the motor will still try to achieve the same calculated rpm so will draw still more amps and burn out sooner or later.
It is the amps (which can be measured) that the motor draws to drive prop at full power that is the limiting factor not the achieved motor rpm.

 

[theo44]

I agree, But that motor is not turning, i don't think turning 27000 with the prop on. I thought some one might of put a tac on a proped motor to see the rpm's.