Originally Posted by CEFOSKEY
The idea of rotor momentum is what allows yaw control on fixed-collective coaxial RC helicopters. However, this is controlled via variable differential Nr through the throttle of two seperate motors.
I highly doubt that rotor momentum plays a big part in yaw control. Unless you are considering they have so little momentum that it is easy to accelerate/decelerate them quickly. The torque generated is predominantly a function of rotor speed, and not the acceleration of the rotors. But maybe this is what you were saying.
-- IFMU