[SU4] empty_inerta_tensor breaks CG PERCENT

[MSFS 2024] Bug Reports Aircraft
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1

Version: 1.6.5

Frequency: Consistently

Severity: Blocker
Marketplace package name: N/A

Context: When editing, in flight

Similar MSFS 2020 issue: N/A

Bug description:

When the empty_inerta_tensor is enabled in flight_model.cfg, the Longitudinal CG % will no longer update when payload stations are loaded.

empty_inertia_tensor = 1180.11, 3675.37, 2683.62, 228.84, 0.625, 0.0007

station_load.0 =0, 3.765, -0.885, 0, TT:MENU.PAYLOAD.PILOT, 1
station_load.1 =0, 3.765, 0.885, 0, TT:MENU.PAYLOAD.COPILOT, 2
station_load.2 =0, 1.104, 0, 0, TT:MENU.PAYLOAD.BAGGAGE, 6

In this configuration, there are two pilots sitting in tandem. Baggage hold is only certified for 24 Lb. (Yes, 24. no zeros missing)

Repro steps:

Test with a small aircraft preferably, where pilots sit upfront and really change the CG position

  • with an empty_inertia_tensor enabled, use either the EFB of the SimVar watcher to modify the payload station weights.
  • CG PERCENT SimVar will not update as expected (stays about 46% in my case)
  • Repeat experiment by commenting out the inertia tensor. Now CG PERCENT will update as expected. (changes from 46% to about 30% with pilots. as expected)

(Note: The debug aircraft weights will not update the payload values either way. does it only report the defaults set in the flight_model.cfdg?)

1 Like
2

Hello,

Could you please check/specify the value for the “empty_weight_CG_position” parameter?

If the longitudinal position of the CG (z) is zero, then this result is expected. Otherwise, I will definitely check for an error.

Thank you!

1 Like
3

Hello,

empty_weight_CG_position = 0.39,0,0

In my case, it is not zero.

In case of zero, will inserting a minute value also work?

Regards,

Mario N.

4

Hello,
thank you for your fast reply,
As far as I can see, the empty CG is at:

x = 0.30 (right)
y = 0
z = 0

I guess you probably meant to set it to 0.0,0.39 to have the CG slightly forward?

If CG.z=0 and you place two pilots, one behind (-0.885) and one in front (0.885) of the empty CG, the longitudinal position of the CG will not change.

Andrey / Asobo

1 Like
5

x = 0.39 (right)

sorry for typo :slight_smile:

1 Like
6

Hello there,

hmm, if I am not mistaken, these entries follow the LON, LAT, VERT scheme. The data is shifted as Z, X, Y. It can get pretty confusing since all the newer things use the X, Y, Z setup.

If the inertia tenso is disabled, the CG moves forward considerably when adding the pilots. they are located 3.765 forward of datum. CG is 0.39 forward instead.

2 Likes
7

Hello Mario,

I’ve checked with the SDK, and indeed, it says the order for the empty CG is exactly Z, Y, X, as you wrote (which is a bit of surprise to me). I will take a deeper look at this issue, thank you for details!

Andrey / Asobo

2 Likes
8

correction: Z, X, Y

1 Like
9

Thanks for looking into this.
Also interested in resolution.
Regards
stu

1 Like
10

@MariopilotPD808

Hello Mario,
the fix is coming soon,
thank you for spot this bug in time!

Andrey / Asobo

2 Likes
11

Hello @MariopilotPD808

The fix is available with SU4 beta 1.6.11.0.
Let us know if this solves your problem.

Regards,
Sylvain

1 Like
12

Thanks for fixing this one. CG% now responds as it should with the inertia tensor :slight_smile:

2 Likes