Why the internal mixer?
Naturally, the control signals generated by the auto-pilot require the same mixers as the control signals generated by the pilot, which vary according to the swashplate linkage. The integral mixer is therefore a basic necessity. This has a useful side-effect in conjunction with the integral tail rotor gyro, and one which a conventional tail rotor gyro cannot provide: revo-mix (tail rotor compensation) is possible with the gyro in heading-hold mode. Revo-mix is the collective pitch – tail rotor mixer which cannot usually be used with heading-hold because it would affect the nominal value. Torque changes occur when a collective pitch command is given, but the system compensates for this right at the outset, i.e. it provides additional support for the gyros holding power. This combined heading-hold / revo-mix gyro is capable of responding even before any yaw movement occurs, i.e. it measures the effect and corrects it, so this combination provides optimum dynamic stabilisation. It is reco
