by design Turbulence effects

[aekki]

So, I was just doing a leg between CYEG and CYVR, and noticed that above rocky mountains where theres turbulent air the turbulence seems to only affect the pitch axis which is swaying up and down like crazy and feels like its just balancing on the center of gravity rather than dynamically moving in the air, there seems to be little if any roll or lateral moment occurring in turbulent air, feels like the same behavior as the default a330 which also sways unnaturally only on the pitch axis. Is this really indented behavior or just a "limitation"?

Edited October 23 by aekki

[richboy2307]

Hi @aekki

From the dev team:

Quote

It’s a bit of both—limitations with the sim’s CFD modelling and some exaggeration of the simulated effects. We use CFD on all our larger airliners because it allows us to simulate cooler effects such as dynamic weather interactions on the FM. At lower levels for example, you'll notice you have to fight the controls a bit more during approach, which is fully representative of the real aircraft. The same applies to crosswind and ground effects. These effects are enhanced with CFD FM, and in 2024, they’re even more accurate as the sim can now incorporate the shape and drag profile of the nacelles.

The turbulence you experienced on this flight is due to the sim simulating mountain wave turbulence. This can be seen by enabling thermals in the weather toolbar menu, and when an aircraft with CFD flies through these waves, the effects on pitch can be quite strong—giving G-loads up to about 1.2. Since there’s no native headshaking in the camera system, the motion can feel abrupt when the FBW system is actively trying to return to the load factor target. At higher flight levels, the elevator naturally becomes more effective, giving more effect to this correction. If you want to experience the pure FM feel, dropping the A343 into direct law would do that - you'll note it’s very sensitive at higher FLs without any protections that reduce maximum elevator deflections based on speed, weight, and CG—this is in line with real aircraft data which we have accurately simulated.

Regarding the lack of roll effects from turbulence, that’s unfortunately something we can’t control directly, as it’s injected from the sim. The mountain wave effect, as shown in the image, is linear and not rolling.

To reduce turbulence effects around mountain waves, especially since CFD was introduced, the sim has added the Settings > Assistances > Turbulence option, where you can choose between LOW, MEDIUM, or REALISTIC. Non-CFD aircraft sometimes don’t feel turbulence as much, leading users to select higher turbulence levels. For CFD-equipped airliners however, we recommend setting this to LOW as to lessen the exaggerated impact of the mountain wave effects you described.

Hope this helps explain why we use CFD, the benefits it provides, and how you can adjust settings to better match your experience.

 

Thanks!