If you’ve ever bought a typical cheap motor from a site like Hobby King, you might notice that after a few days, your motors will start getting louder and not sounding the same as they did when you first got them. The reason for this is because the bearings are vary low quality and will where-out rather quickly. I’ve experienced this with a few different motors and it’s really annoying (especially the NTM’s). If you have bad bearings or unbalanced motors, it can cause vary bad vibrations which isn’t good for your quadcopter. Vibrations can cause screws to come loose, Jello effects in video and even electronics to fail, so it’s good to buy well-balanced motors with nice bearings.
In this review, I use an app on my iPod to test the vibration levels of each motor. The first motor I tested was the SunnySky 980kv X2212-13. I then tested the NTM Prop Drive Series 28-30S 900kv. The NTMs did vary bad compered to the SunnySky motors.
I’ve used the SunnySky motors in my QAV400 for about a month now with over 30 flights, and they still preform better then the NTM motors did when I first opened them.