[SU15] flight_model.cfg - Fuel_flow_gain - causes torque to zero and other issue

[MSFS 2020] Bug Reports Aircraft
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1

Version: SU15 - 1.37.9.0

Frequency: Consistently

Severity: High

Context: *Developing/Debuging helo turbine engine

Bug description:

The SDK says that this cfg parameter is no longer used. So I comment it out.
Running AE puts it back in - along with

fuel_flow_gain = 0 ; 0.05 ; Gain on fuel flow NOT USE in MSFS see fuel flow PID - added by AE
n1_and_mach_on_thrust_table = ,,,,,,,,,,,,,,,,,,,,  ; jet only - added by AE
corrected_airflow_table = ,,,,,,,,,,,,,,,,,,,, ; jet only - added by AE

I am debugging why my helo turbine has no torque. Using AE - put the fuel_flow_gain back in with a zero.

Now I have my torque in the engine. and simvarwatcher shows it.

fuel_flow_gain - commented out

DA40CGDFQ_Snap_2024.03.25_13h30m59s
DA40CGDFQ_Snap_2024.03.25_13h30m59s1219Ă—253 20.7 KB

DA40CGDFQ_Snap_2024.03.25_13h30m43s
DA40CGDFQ_Snap_2024.03.25_13h30m43s1046Ă—1006 77.3 KB

fuel_flow_gain - not commented out

DA40CGDFQ_Snap_2024.03.25_13h27m30s
DA40CGDFQ_Snap_2024.03.25_13h27m30s1110Ă—301 22.6 KB

DA40CGDFQ_Snap_2024.03.25_13h27m5s
DA40CGDFQ_Snap_2024.03.25_13h27m5s1036Ă—997 74.8 KB

PLEASE ADD A BIG NOTE IN THE SDK - OR BETTER YET FIX THIS ISSUE
Some of the other parameters have a note that says must remain in cfg or it thinks it’s an air file.

Put me on the alpha/beta team for MSFS 2024 - seems you guys need a lot of help with testing things … Sorry but this is very frustrating with these issues.
Thanks

Repro steps: - comment out fuel_flow_gain

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2

Hello @DA40CGDFQ

This is related to this problem:
Removing deprecated(!) variable “fuel_flow_gain” from engines.cfg causes system breakdown - Questions & Community Discussions - MSFS DevSupport (flightsimulator.com)

If some specific config parameters are missing, although no longer used by MSFS, the config reader will try to look for an airfile instead. This format is still in use by some people so we cannot change this behavior without introducing regressions.
The Aircraft Editor handles this and now always write the affected parameters.

We just need to update the documentation of fuel_flow_gain, as we did for static_thrust:

image
image2482Ă—240 28.9 KB

Regards,
Sylvain

1 Like
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Backwards compatibility has to stop. Still “use by some people” really? 2004 tech used in 2024?

Just put a big warning message that all air files and legacy is deprecated and will no longer be accepted into the MS Store. It’s up to the dev to take the heat.

This would allow devs with up to date skills provide aircraft that work properly. God I hope MSFS 2024 removes FSX, FS2004 tech completely. I can only think what spaghettis code is in the sim to maintain this terrible idea.

1 Like