Help please.
Yaw is achieved in the coaxial helicopter by 'differential collective'. In addition, the two rotors are mechanically linked so that the blades always cross at the same azimuths.
I believe that during powered flight, when right pedal is applied; the collective pitch on the CCW rotating rotor increases, and the collective pitch on the CW rotating rotor decreases. The increase of the induced drag in the CCW rotor, combined with the decrease of the induced drag in the CW rotor causes the craft to yaw CW.
During autorotation, the pedal action is mechanically reversed so that the application of right pedal will still to cause the craft to yaw CW. By implication, this means that during autorotation the application of right pedal will cause the greater drag (induced &/or profile) to now be experienced by the other rotor.
I'll be damned if I can figure out the aerodynamic logic for this transposition of the drag.
Can anyone help?
