Rudder and/or Yaw-Damping

[snooky_g]

Hi all,


First, JH, thank u for your great and famous software. I´m now using it since B30. The only thing is
that over the time i m using FMGS i m not satisfied with my rudder-configuration in manual flight.


very often it happens on short final, after disconneting the AP, that the rudder deflections are very high after giving some input on roll and the aircraft is getting way out of track.


On the Flightcontrols-page i´m watching the rudder-deflection and if there is a deflection and i start using the pedals, then first the rudder swings back to zero and after that deflects to the
given input by the rudder pedals. Putting the pedalsr again to neutral it stays there for a moment and again it starts to deflect (for yaw damping?). In total that often that brings me way off track so the
touchdown is on the very left or right hand side on the runway and it becomes not a good landing.


Yesterday, for example, i did two short manual flights EDDL-EDLW_24 with actual weather (FSGRW, which was a little bit windy) and on final i tried to slip the aircraft just a little but because of the rudder-deflections i ended up in go around for 3 times.


In the Airbus-FCOM it says, that if the rudder is deflected and the pilot give some input by peddals this input will be added to the actual rudder deflection. Am I right?


Do you have any suggestions?


Regards, Stefan


3xP3D v2.4, 3xCoreI7 GTX 770, Saitek X52 and Rudder and TQ, CoreI5/FMGSB36.1, FSGRW, AivlaEFB, PFPX, Topcat

[jeehell]

Hi Stefan,


The A320 has automatic yaw damping and turn coordination.
The way they interact with rudder input is not very well described.

For all I know, once you use manual rudder inputs, the auto coordination and yaw damping stops, the sum of actions you describe is in fact here only to avoid having the pedals moving while the aircraft automatically counters Dutch roll, and keep sideslip at 0.
What is however true is that the rudder surface should move much slower when going from auto to manual, instead of jumping instantaneously to the manual input, I'll try to model that in a future version.

However, when landing, slipping the aircraft down is a very bad idea on the airbus fleet, they really are not designed to do that, since the controls are demand based, there are chances to get full spoilers deployment very near to the ground on one of the wings. This is also why Airbus does not recommend crossing controls for Xwind operations (and also gear resistance).

I did reduce the rudder sensitivity during flare in 36.1, I will try to tune it a bit more.

Regards,
Jean Luc

[snooky_g]

Hi Jean Luc,


thank you for your answer, and again, i´m very impressed about your hard work!
(knowing it is a hard work, because i´m working as a software engineer
in german software company).


You are right about airbus´ poor description of rudder interaction. I´ve read
tons of offical airbus manuals and docs (FCOM, Flight Crew Trainig Manual, Maintainance Manual etc etc). Nearly everything i´ve found in the web, but very less explanations about the correct use of rudder.


So I think, the best way is to perform a go around in xwinds and not to end up like
Lufthansas Flight 741/RJAA in March :-)


http://www.youtube.com/watch?v=UK5Nm_rKu50


Kind Regards ,
Stefan