So I recently developed an interest in quad-rotors and was getting stated with its dynamics. I am particularly intrigued by the yaw motion of a quad-copter which comes into effect as a result of torques of the motors. When the motor torques are variable, we observe the yaw motion as result of a non-zero torque on the system. But I was wondering if we would still observe yaw in vacuum(if we manually suspend the quad in vacuum) by create an imbalance in the the motor torques. What do you guys think?