I have always done this but it seems many don't. You need to "feel" the resistance in your motors. If you don't, you're never going to know if something is going amiss. Yesterday, I did this and one motor didn't "feel" right. It had more resistance that the other three. I took my air compressor, turned it down to 30psi and blew some air through the motor (making sure my compressor was clear of any water). It was still not right. It still had a bit more resistance than the other three. I took it down to the shop to look at it further. It was clearly different.
I ordered up a few more motors and decided to look a little deeper. These are sealed bearings, right? They don't need any oil, right? Having worked on motorcycles my whole life, that's what it "felt" like to me, like it needed oil. I have some Tri-Flow "Superior Lubricant" oil here for other stuff. Super lightweight. I decide to try it. It has a tiny nozzle, almost like a syringe on it. I put a drop on the top bearing, pull the motor from the arm and put "a drop" on the bottom bearing. I turn the motor back and forth, over and over again. It seems like its working. I decide to do the same to the other three motors. It all looks good. I give it a bit of time to seep in and keep hand spinning the motors. First sitting on the landing gear and then turning it upside-down.
I hook up the RC to the bird and power her up (no props) and spin the motors for a while. Let her sit again for a bit. Now the motors all feel close to the same. I push a bit more air (low pressure) through both the top and the bottom of the motors just to spread it around and get the residual out and all is good. Motors feel consistent and she flies like a dream! Sealed bearings or not, it had a big impact.
Am I telling you to do this? Hell, no! I'm telling you that it worked for me (so far). I'm just sharing my personal experience.
Just really get to know your bird.
Jerry
I ordered up a few more motors and decided to look a little deeper. These are sealed bearings, right? They don't need any oil, right? Having worked on motorcycles my whole life, that's what it "felt" like to me, like it needed oil. I have some Tri-Flow "Superior Lubricant" oil here for other stuff. Super lightweight. I decide to try it. It has a tiny nozzle, almost like a syringe on it. I put a drop on the top bearing, pull the motor from the arm and put "a drop" on the bottom bearing. I turn the motor back and forth, over and over again. It seems like its working. I decide to do the same to the other three motors. It all looks good. I give it a bit of time to seep in and keep hand spinning the motors. First sitting on the landing gear and then turning it upside-down.
I hook up the RC to the bird and power her up (no props) and spin the motors for a while. Let her sit again for a bit. Now the motors all feel close to the same. I push a bit more air (low pressure) through both the top and the bottom of the motors just to spread it around and get the residual out and all is good. Motors feel consistent and she flies like a dream! Sealed bearings or not, it had a big impact.
Am I telling you to do this? Hell, no! I'm telling you that it worked for me (so far). I'm just sharing my personal experience.
Just really get to know your bird.
Jerry