T-Motor MN2806 KV650 with Arducopter 4.2.x

Does anyone know why my autotune failed to tune? Is it due to HNTCH being enabled?
Prompting the pilot to tune manually.

Because the basic/initial tune is poor.

Not sure is it due to 4.1.x and and above issue. Previously other drones were done using 4.0.x

All along the craft we build with Cube series do not use vibration damping mount.

I think I will try reduce the aggressive to see any good surprise. This is the first time I tune a drone using a low KV motors.

You will most likely be surprised with an even worse tune by lowering aggression.

I don’t quite get it, it started when I lowered the default PID by 50%. Then it stopped and started to prompt the pilot to manual tune. No different if I turn off the INS_HNTCH_ENABLE.

The default initial parameters and lowered values are both flyable and only noticeable a slight height drop when pitch and roll. No oscillation so call.

4.2.3 firmware.

I am now suspecting MOT_THST_EXPO with the digital ESC and the motor. Many T-Motor users pointed out very linear motor curves.

after changing thst_expo from 0.66 to 0.99, I got a recommended thst_hover value of 0.2503457. I hope the autotune starts and works next, finger-cross.