Dual Rotor Control Methods

lever57

The top of this web page is a general overview.

Some Intermeshing information;

An interesting craft was the Coaxial Sikorsky S-69 ABC

Hope this helps.

Dave Jackson

Thanks, Dave. That site explains a lot.

One thing that occured to me was with all the cross coupling that can happen on laterally displaced rotors or synchropters when you use either differential cyclic or differential collective for yaw control, why has no one used rotor blade tip brakes for yaw control? Certainly it works for co-axial designs. Maybe not responsive enough? Inefficient perhaps?

Tom P.

Tom,

The tip-paddles are a good method for the coaxial and they probably produce little, if any, cross couplings at slow forward speeds. However, Kamov elected to rely solely on differential collective and they use a mechanism to switch the pedals for autorotation. Perhaps Kamov felt that their mechanism was simpler than the tip paddles, plus they were willing to put up with 'indecision's' of their mechanism at low collective settings.

Opposed cyclic is used in the tandem and, I assume, that it was also used in the side-by-side and interleaf configurations. This method should produce minimal cross couplings at slow forward speeds in the side-by-side and interleaf. I think that it should also work properly during the transition and flight in autorotation.

Like the Kamov helicopters, yaw control of the intermeshing configuration is not perfect. Tip-paddles would eliminate the problem of switching pedals for autorotation, however they will not solve the torque-pitch coupling, because of the angle of the masts. This is some preliminary work on yaw control for the intermeshing configuration, if interested.