ORIGINAL: krproton

Yes, the 4040 has a higher kV than the recommended 3180, but the 3180 is already being pushed to its limit (over the limit?) on 3S with a 4.75 x 4.75. Even with that motor you can't fly full-throttle the whole flight or you will cook the motor eventually. If you jump to a 4040 and use the same prop and battery, you're DEFINITELY going to smoke the motor. What you need to do is run it for a second or two with a Watt meter and read the current its drawing and compare that to what's the limit for the motor. I've found that for most motor and prop combinations one woud run in a plane like this you can shave about 30% from the static current to predict what you will get in flight. In the case of the 3180 it draws about 28A staitc which, less 30% (to find out what it's actually going to draw in-flight) = about 20A (in flight). But the 3180 is rated for 17A constant current/20A bursts, so as you can see she's right at the edge already.