[1.9 Advanced Blade Controls]

Does "Yaw" do anything at all on rotor blade controls?

I have yet to find it do anything; just built a Chinook-style and did read the manual as suggested, should be for yaw that the rear rotor cyclic roll to one side, front rotor cyclic roll to the other to create yaw effect.  

Would be good if we had an option there for yaw to set it to be cyclic one way or the other on a per-rotor basis and let designer figure out what it should be; so yaw can function identically to roll or opposite of it(but bound to yaw axis).  This is how the actual chinook works as the controls are mixed together and rotation can be around front or back axis by using the pedals(for yaw) as well as the cyclic for roll together.

So would be great that for "Yaw" rather than it just do nothing full stop, it can work either same as roll or opposite of it, and for there just to be a switch there for the designer to choose what it does.  Then proper chinooks(and I guess a bunch of other stuff too) can built and yaw is just not doing nothing.  All that is needed is another binary option that if yaw is on, whether it acts same as roll or roll inverted(bound to yaw axis of course).  And helicopter blades can start with "Yaw" disabled completely as a default state so as not to confuse beginners. 

Am I missing something here, does yaw actually work in some contexts ?

To answer my own question: Yaw works for vertical blades only, in which they have collective control to counteract main blade torq and provide yaw.

It would be great if for each input { pitch, roll, yaw }, that one could MANUALLY choose which action it did.  Rather than there being just on/off. 

Option 0: Off

Option 1 : Automatic -> KSP chooses as it does now,
Option 2 : Cyclic Pitch +
Option 3 : Cyclic Pitch -
Option 4 : Cyclic Roll +
Option 5 : Cyclic Roll -
Option 6 : Collective +
Option 7 : Collective -

Then we can have true Chinooks with true yaw(as per manual).  We can have drones that can rotate in yaw without having to use Kals to change RPM to create torq differential.  Chinooks have a "mixer" that mixes the hydraulics so that both roll and yaw can be added together, same simple solution can be done when 2 axis control same cyclic, just add together.  These are the only helicopter swash plate controls and any blade/rotor configuration can be made if they can be manually chosen like this.

So I would humbly request SQUAD implements this in next update so we can finally have helicoptering perfected, and have real chinooks and drone-style yaw control with swash plates and not rpm altering.