Hi

 

1) What is exactely the yaw axis?

2) Can we manually do a yaw turn?

3) When do we use yaw?

4) If we can do it manually, how do we do it?

 

Thanks

http://en.m.wikipedia.org/wiki/Yaw_(rotation)

Thanks but can we do a yaw turn manually? How do we do it? Why do we use it? And for Airbus, the side-stick is connected to the ELAC computers but it can also send signals to the FAC computers for YAW DAMPING. Thanks

 

 

2) Can we manually do a yaw turn?

 

Yes, you can yaw manually, but it's quite hard to actually "turn" without using ailerons

 

 

 

3) When do we use yaw?

 

Primarily to keep the aircraft balanced in flight, usually in a crosswind or turn situation.

 

 

 

4) If we can do it manually, how do we do it?

 

Using the rudder pedals to actuate the rudder fin.

Thanks so if we aee flying 320 330.. if we turn the stick the plane will decide if it will use alerons, spoilers or yaw to turn. Depending of the turn, the wind... Am I right?

Back to basics: In a small aircraft with little or no automation (eg Cessna 172), you would commence a turn by turning the control yoke and applying the necessary rudder inputs to keep the aircraft in a coordinated turn.

 

This is basically what happens in larger aircraft except that the Yaw Damper manages the rudder inputs to balance the aileron/spoiler roll inputs (processed by various flight control computers before any controls are actuated) by the pilot.

Ok so when you are flying with FBW, the yaw turn is "mixed" with the ailerons. So rudder and ailerons are turning. If required, it can choose. But the pilot is simply turning the stick. Can there be ailerons and spoulers at the same time?

If you don't use both the rudder and ailerons in a turn, the turn will be uncoordinated, either skidding or slipping and not a comfortable feeling for passengers. In most large aircraft ailerons and spoilers are used simultaneously to bank the aircraft.

Ok so.if we want to manually do.a yaw turn, we have to use rudder and ailerons. Or maybe it is for yaw damping only.

 

Yaw damping = aileron+ rudder

yaw turn =rudder

 

airbus uses the first one with the computers. So if you can see in a 330 that the rudder is moving, so the aileron is also moving. This is the yaw damping

So it means that if the rudder/spoiler is moving/deployed, the ailerons are moving too.

Oh sorry! I forgot my question! Am I right on my previous post ?

Now that I think about it, maybe the FAC can use yaw coordination, but it can also simply not use it and only turn the rudder or only the aileron (So ELAC) or simply both (ELAC and FAC)... Same thing for Spoilers... If you need a turn coordination, you use it... (Ailerons and spoilers)

But maybe I am wrong, maybe the yaw dumper is always coordinated with the ailerons. In this case, I am maybe right in my previous post...