I have been running the Turnigy D2826/6 2200 Kv motor on my highest time NAMC Mig-35 shown below for 280 flights.
- I have been noticing that the motor tends to whine/squeal more than normal, normally between about 50-75% throttle setting;
- The motor has been considerably hotter after flights than normal, even though the temperature is considerably cooler at the field when I am flying as fall has arrived;
- I noticed as you can see in the pictures below that something was obviously burning or disintegrating in the motor, creating a black dust that was being thrown out of the motor. In the picture on the left, it is easy to see that something was being thrown out of the gap between the bottom of the "bell" and the base plate of the motor. In the picture on the right it may be more difficult to see but where the silver tip of my pen is, there is quite a bit of black powder in the groove indicated;
- If I hold the "bell" between my thumb and forefinger and pull it away from the base plate, there is about twice as much play as there is in a new motor; and
- when I free spin the motor by hand, it runs much louder and rougher than a new motor, even after I apply some light sewing machine oil, so something is not quite right.
These motors are so inexpensive that it really isn't cost effective to replace the bearings, rather just put a new motor in the plane, fortunately I have a few new ones still in my supply bin :). Overall, I have been always been very satisfied with this motor from Hobby King, of all the 2826/6 2200 Kv motors that I have used and tested in the "mild" category of our NAMC Parts List, it is definitely my overall favorite.
I'm sure I could probably push many more flights out of this motor, I don't think it will get hot enough to catch fire, but I do think there is a definite potential for the bearings to completely self destruct and cause the motor to cease in flight, so better to retire it with dignity and move on to another motor before it costs me a plane, especially one that I have so many flights on.
I just wanted to pass along my findings as something to keep an eye on with all your brushless motors. In all honesty, considering how inexpensive all the motors that we use are, I have only had problems with one other motor. With one of the first Focal Price 2212/6 2700 Kv motors (which interestingly enough have been out of stock for almost a year now) I ever used, the bearings ceased up after about 100 flights. Considering in the three years and close to an estimated 4000 flights I have flown these park jet motors, I have only had two motors go and neither time it has cost me an airplane, I'll take that level of performance for very low investment any day :).