Well, they announce this series as high quality brushless motors, and I had a couple of different types from NTM series with same issues.
This motor is very bad, don't buy it!!
I have used it for my H-King Composite North American P-51D MUSTANG 1200mm (47") and only did maiden flight with it. It has a lot of vibrations, and when I disassembled the motor I could see why.
Bearings are unmatched with the shaft and there is too much of free space between shaft and bearing itself.
Replaced it with Turnigy D3548/4 1100KV motor which performs excellent.
I noticed that other customers had similar issues with these motor series so my suggestion is to avoid them.
You can see on my video how it looks inside:
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