Excessive Yaw / Rubber Band Effect on Most Planes

[enright 496]

Just wondering if I'm the only one that experiences this: a subtle "bouncy" yaw motion when turning - as if the nose is being pulled along by a spring. It's noticeable on any aircraft - even twins - so it's not caused by P-Factor. I've even noticed it on big jets like the Fenix A320 and PMDG 737.

I noticed it before SU10, but it seems more pronounced lately. At one point, I thought it might be caused by spurious inputs from my controllers, so I unplugged them all and I see the same effect with a just mouse and keyboard connected.

The "springiness" seems proportional to the amount of wind that is present and nearly goes away completely if the winds are calm. I'm thinking inertia in the flight model is too low - planes are not as easy to pivot laterally in real life (thankfully - it would be extremely nauseating). Either that or the flight model is not smoothly calculating the yaw rate and is falling behind / catching up.

Is it just me though? Does anyone else notice this?

[Bert Pieke 7,584]

57 minutes ago, enright said:

I'm thinking inertia in the flight model is too low - planes are not as easy to pivot laterally in real life

Some flight modelers (Rob Young's G36, and the FSW C414 for example) have increased the YAW MOI value quite considerably in their flight models.  That is likely based on the same observation..

Edited August 12, 2022 by Bert Pieke

[sd_flyer 6,034]

Sounds like adverse yaw

https://aerospacenotes.com/flight-dynamics/adverse-yaw/

[jcomm 5,890]

For me it is observed more intensely since the gusts have been re-enabled with SU10.

The wobblieness is due to the gusts and up / down drafts that are present either through the weather forecast GRIB files or whenever a METAR reports "G" or "V" in the winds section.

It's been there in MFS since the beginning. It's also a "plague" in XP FWIW if turbulence is present and just like in MFS, some authors add additional MOI to their models, whch IMO is not the ideal approach, having it's consequences in other aspects of the FD, but it's probably easier for pleasing users while the core code isn't fine tuned.

Just like in other aspects, of what I can recall, Flight Unlimited was still my preferred flight simulator in dealing with turbulence / gusts / up and down drafts affectiing aircraft.

I see sd_flyer's point in the above post, since you mentioned - "yaw motion when turning". But does it really only affect you during turns ?

Edited August 13, 2022 by jcomm

[enright 496]

11 hours ago, sd_flyer said:

Sounds like adverse yaw

https://aerospacenotes.com/flight-dynamics/adverse-yaw/

That could be - however it occurs during manual coordinated turns, and with rudder assist on, and on planes that have an automated yaw damper like the a320 and 737. And it only occurs in gusty conditions. It don't think the adverse yaw effect should be that noticeable under those circumstances

6 hours ago, jcomm said:

For me it is observed more intensely since the gusts have been re-enabled with SU10.

The wobblieness is due to the gusts and up / down drafts that are present either through the weather forecast GRIB files or whenever a METAR reports "G" or "V" in the winds section.

It's been there in MFS since the beginning. It's also a "plague" in XP FWIW if turbulence is present and just like in MFS, some authors add additional MOI to their models, whch IMO is not the ideal approach, having it's consequences in other aspects of the FD, but it's probably easier for pleasing users while the core code isn't fine tuned.

Just like in other aspects, of what I can recall, Flight Unlimited was still my preferred flight simulator in dealing with turbulence / gusts / up and down drafts affectiing aircraft.

I see sd_flyer's point in the above post, since you mentioned - "yaw motion when turning". But does it really only affect you during turns ?

Whew - I'm glad I'm not the only one that experiences this. It's a bit immersion breaking, and I haven't seen any one else mention it. 

It's definitely most noticeable when turning - but I'm not sure it's adverse yaw for the reasons I mentioned above. 

100% agree about Flight Unlimited. I'm not sure what the secret sauce was in that flight model, but it definitely "felt" like you where moving through the atmosphere - it had a softness to it that was very realistic. I'm tempted to find it and run it to see if it stacks up to modern sims, or if it was simply ahead of its time and better than what existed back then.

[enright 496]

14 hours ago, Bert Pieke said:

Some flight modelers (Rob Young's G36, and the FSW C414 for example) have increased the YAW MOI value quite considerably in their flight models.  That is likely based on the same observation..

Ahhhh moment of inertia - I knew my physics classes would come in handy some day. As it happens, the FSW 414 is one of the more "yawwy" planes in SU10 beta for me. The turning rate is very "sputtery" - normal turn rate, then slow, then normal, etc... Will try Rob's G36 and see how pronounced it is there- he definitely works some magic into his flight models.

[sightseer 895]

I'm glad to read this here because I've been thinking the same thing.  I fly the C172 and when a gust comes along its like my plane has been punched in the jaw and then it acts like its on a spring of some kind.  It seems to me that winds should move a plane around in 3D space more and though they should weathervane a bit, I can't imagine any reason for the 'springiness'.