Payload moments of Inertia Wrong

Version: SU 14 - 1.35.21.0

Frequency: Consistently

Severity: High

Context: All Aircraft

Bug description: Station_load moments of inertia calculation is wrong. This bug dates back to older FS versions. MoI for payloads are calculated by adding together the masses and calculating their average CG. Then the point-mass MoI is calculated and added to the Empty Weight Moi as entered in flight_model.cfg.
Instead, MoIs foir the individual station_load point-masses shall be calculated individually, then added together.

Repro steps:
Select an Aircraft where:

  • station_load A is located in front of CG
  • station_load B is located behind the CG
    Using the payloads menu:
  • set both to zero
  • take note of current Pitch MoI (using aircraft debug weights SDK window, for instance)
  • add a large weight into station_load A, take note Pitch MoI increases
  • add a large weight into station_load B, take note Pitch MoI decreases!

I would suggest the MoI calcluation shall be fixed, and a switch to use the new method added to flight_model.cfg (ex. use_new_MoI_Calculation = 1 under [weight_and_balance])

6 Likes

that explains alot!
thanks for reporting

Hello @MariopilotPD808

This issue is already tracked on our side.
I’ll update this post if we make progress on this.

Regards,
Sylvain

1 Like