Hi everybody
i have some problem while flying quadcopter via kk2.1.5 .
When i fly the 2nd motor will slow down and stop after  some time . What may be the reson? Pl help me is it due to the settings in the board or other cause.?

I have tried KK board once. Its shows abnormal behavior each time in different angle. May be the board is having some issues. Better got for APM/ PX4. They are steady. But costly, needs some knowledge about calibration tuning etc...