Mystery of Yaw Damper

[TLB]

Yaw Damper

Had one of those on the old CF-101 Voodoo. Part of the Automatic Flight Control System, it had a separate ON/OFF switch and performed two functions:

1. if you manually applied a bunch of rudder, say to the left, and then let go & centralized the rudder, the aircraft would yaw back the other way (to the right) and after one cycle the yaw damper would in fact dampen out all the yaw instead of yawing back & forth until the aircraft stability would eventually zero out the yaw;

2. more importantly, it would automatically counter adverse yaw effects. In other words, if you want to turn left, you input left aileron and the aircraft starts to roll to the left, but it will also yaw in the opposite direction (yaw right in this case). The yaw damper would recognize this and automatically input left rudder to counter the right yaw. You could keep your feet off the rudders and roll left or right and the yaw damper would always keep the ‘ball in the centre’.