Dutch roll simulation

[Alex Whittingham]

I'm about to brief a 3D animator to show dutch roll building up on a typical airliner (probably B737) at high TAS. My question is, with the yaw stabs out, as the dutch roll builds will the control surfaces deflect? My guess is not.

[safetypee]

With irreversible power controls they should not, but if the pilot gets in the loop !!
Stick fixed or stick free.

In order for DR to build up, you should have an initial disturbance; atmosphere or pilot ? And then which axis inputs the disturbance.

In case your animator requires some background maths.
https://www.nasa.gov/centers/dryden/pdf/88484main_H-2106.pdf

There may be some simple animations on line like this one https://m.youtube.com/watch?v=oLe8ajpGNTs
Perhaps not that accurate - would reversible manual controls move if stick free.

https://m.youtube.com/watch?v=h-RNbdvrgF0

https://m.youtube.com/watch?v=YTGp-hoUZG0

[Chesty Morgan]

I'm about to brief a 3D animator to show dutch roll building up on a typical airliner (probably B737) at high TAS. My question is, with the yaw stabs out, as the dutch roll builds will the control surfaces deflect? My guess is not.

As part of post C check air tests I'm required to incite a dutch roll with the yaw damper disengaged and then engage it to ensure it damps correctly.

There is no control surface deflection until the YD is engaged.

[Alex Whittingham]

Thank you all, the term yaw stabs may have slipped in from a past on V bombers, sorry, I did of course mean Yaw Damper. I'm rather constrained to the B737 as it is the model used to illustrate Autoflight in the ATPL syllabus. I have done a you tube trawl but surprisingly there doesn't seem to be much illustrating this. Knowing that the max rudder limiter deflection in the high altitude cruise is 5 deg is particularly useful.

I think may well illustrate an induced oscillation, lightly damped with the yaw damper out then recovering rapidly with the yaw damper selected on.

[Bergerie1]

Chesty Morgan,

It was the same with the VC10 on which the Dutch Roll doubled its amplitude every 15 seconds.