Hello everyone, 5 of our copters use KDE motors (mainly 4014XF and 5215XF series) and we have tons of hours flight time on them. I wanna share some tips on the maintenance of these motors: If you are flying a heavy payload (AUW around 14-15kg) with 4014 series motors in a hot climate, be sure that you check the bell movement. If it plays, just apply lock tite to the shaft screws and secure the bell again. After flying in hot weather, almost all of my 4014XF-D5 motors had this bell play problem. With one of them, the problem was so serious, the bell was just about to release itself from the motor. So be sure to check them out frequently. KDE has retaining collars at the bottom of the motors, so it will be very easy to take care of them. On the other hand, there is no issue like this on 5215 series. Their shaft is much stronger and the bell is locked into its position a bit differently. The bell is not going anywhere with 5215XF motors. This tip is for cleaning the motors: If you are flying in a dusty environment be sure to clean motors first with air spray and then open the motor and clean inside with WD40 and some micro fiber cleaning sheet. You will be shocked when you see how much dirt a brushless motor can carry. After cleaning, you will notice that the motors will run much more silent. The cleaning tips can be found here: Always keep a set of bearing and shaft screws with you when you are on a job; a back up motor is always better.
Good tips. Yes 4014 bell/shaft play is horrendous! We actually remove the shaft from the bell housing and use Loctite 638 retaining compound to lock the shaft and bell together. Works well and the bell/shaft play doesn't reappear.
Thank you Ozkan for the summary of the information, and absolutely, brushless motor maintenance is critical for optimal performance and durability. We have instituted additional improvements in production, including Loctite 648 during the press-fit install of the shaft and magnet-bell interface, as well as knurled-tip set-screws for improved hold to the shafts (and a host of other process improvements), so further increase the durability of the motors. Every electromechanical device has its limits, so like Ozkan mentioned above, if running the motors in high-temperatures and rigorous environments, please make sure to routinely inspect the motors to keep the system operating safely and at peak-performance, replace bearings/shafts as needed, and they can last the lifetime of the airframe.