Why do so few of MSFS, ASOBO own aircraft use CFD?

<https://forums.flightsimulator.com/t/new-propeller-cfd-soft-body-simulation-
aircraft-list/504719> I see only one airliner that uses CFD, and that is the
A310. I wonder why not all aircraft are updated with the new CFD Aerodynamics?
If it is better, it should really be in MSFS’s interest to update its
aircraft. Not even the 787 and 747 are updated?

The CFD option is not to enable aircraft to ‘use’ it. CFD is only used for
debugging. So you can turn the CFD option on and off for any aircraft and it
will not change how it flies.

Are you sure?
https://docs.flightsimulator.com/html/Developer_Mode/Aircraft_Editor/Debug/Debug_Aircraft_CFD.htm?agt=index
There page clearly sates the opposite. “

  • When the option is unchecked : In this mode - when the interaction between fluid and rigid body is calculated - the fluid will receive the exact body to fluid force. **However, the body will not receive the exact opposite force. The force received by the body will be overwritten by the aerodynamic forces as computed by the previously existing, non-CFD, calculations (which are run in parallel). **What this means is that the CFDsimulation is aware of the aircraft, but the aircraft will be processed by the non-CFDaerodynamic simulation and ignore the CFDsimulation. Note that in this mode, Newton’s third law is not respected, and the simulation will run as if there was no CFDcalculated, and the CFD can be visualized but has no effect on the airframe.

Hm… no I’m not sure. It does answer your question why it’s not being used: I
doubt if anyone developer really understands what this does and how to use it.

Yeah, it is a very “fluid” :wink: description in the “documentation”.
https://docs.flightsimulator.com/html/Developer_Mode/Aircraft_Editor/Debug/Debug_Aircraft_CFD.htm?agt=index

I tried it on a plane I am developing. The plane flies like a helicopter :slight_smile:
Especially unstable and sluggish in pitch. I have to admit that I did not take
a lot of time to tweak. Hopefully it will envelope into something cool.

I’m going to offer an answer here that might give some insight, at least from
our (Milviz/Blackbird) point of view. CFD is not designed to be a ‘better
replacement’ for something that came before. Think of it as a tool in a
toolbox: it’s yet another setting that can be used to help tailor the behavior
of an aircraft to better match it’s real world counterpart. That doesn’t mean
it’s always needed - if the previous flight model of the aircraft already was
highly tuned to match real world values, adding CFD into the mix doesn’t
automatically guarantee an improvement, nor is even suitable in all cases. It
doesn’t automatically mean that there’s an added advantage to utilizing CFD,
despite what some in the wider user-community might believe.

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That is a little disappointing! I wish they had gone the JSBSim route instead.
Or if possible even more realistic. I remember when Majestic Q400 came. It was
basically a revolution. No they try to invent the wheel again.