Weird Circling (Toilet Bowling) Problem
12 is clockwise, 34 is counterclockwise.
Motor 34 has a higher PWM than motor 12. There is no circling when the battery has enough power, but counterclockwise circling raises as the battery power reduces.
Clockwise circling is always causing louder motor sound than counterclockwise circling when contol copter using RC.
Exchanging both motor1 and ECS1 with motor4 and ECS4 does not improve the statues.