fix(a380x/flight model): A380X Flight Model Update

[donstim]

Fixes #[issue_no]

Summary of Changes

This PR does essentially the same thing (but accomplishes it differently) as #9728. This was necessary to fix the pitch-up/unrecoverable stall and auto-rotation issues for MSFS 2024 as well as 2020. The fixes contained in #9645 and #9728 only work correctly in MSFS 2020. So this PR supersedes both of those previous PRs.

General update to flight model plus:

1. Fixes auto-rotate issue for both FS2020 and 2024
2. Fixes pitch-up and unrecoverable stall issue for both FS2020 and 2024
3. Updates flap and gear drag values to match pitch/power tables

Screenshots (if necessary)

References

Additional context

This PR supersedes (and closes #9728). In addition to working with FS2024, the pitch control at takeoff should be better behaved than in that PR relative to the rotation law. The rotation law should still be tuned, but it should be as big an issue as before.

Discord username (if different from GitHub): donbikes

Testing instructions

1. Test different takeoff conditions (setting the correct pitch trim for the CG) to verify auto-rotate is fixed. You can test at weights up to 575,000 kg.,
2. In flight pitch up and try to stall the airplane. Try this in all configurations. Confirm that it does not stall (become uncontrollable, or drop a wing), then confirm that you can recover to a normal attitude with use of the pitch control alone.
3. Test full flights to make sure there aren't any anomalies introduced.
4. Confirm consistency between EFB displayed CG at current gross weight with the CG displayed at the bottom of the PFD and on the situation display.
5. Confirm that the THS disagree warning appears when advancing the thrust levers to TOGA or FLEX, and when the takeoff config check button is pressed if the pitch trim setting is not within the green band on the PFD (where the set value will not be green). (For this test, enter the correct THS value in the FMS takeoff performance page.)

If you have FS2024, also perform the tests in that sim to confirm the fixes work there as well.

How to download the PR for QA

Every new commit to this PR will cause new A32NX and A380X artifacts to be created, built, and uploaded.

1. Make sure you are signed in to GitHub
2. Click on the Checks tab on the PR
3. On the left side, find and click on the PR Build tab
4. Click on either flybywire-aircraft-a320-neo, flybywire-aircraft-a380-842 (4K) or flybywire-aircraft-a380-842 (8K) download link at the bottom of the page

[aadee9940]

Takeoff at 410T, Using EFB CG of 40%. Flaps 1+F Takeoff. MSFS24.

1. Auto-rotate issue which was really bad on 2024 specifically, is essentially gone. This used to occur in the region of 140kts. After using this fix, the nose stays down firmly on the ground even in the 160kts region. Huge change.

2. The stall issue, which was again made even worse by 2024, is also gone, through testing of my own. With further testing with different/more extensive weights and configurations, someone may find a way to get it to stall.

Anyways, at takeoff gear up. I pitched all the way up to 30 degrees. Previously if I did this, I would've triggered the bug and there would be no saving it. This time however, plane will happily respond to my inputs. Going further, i entered the amber speed range and activated alpha floor, what is important now is that if i can control the elevators and thus the pitch of the aircraft to recover. This is what the aircraft does with the fix, I was able to fully control the aircraft and recover the plane fully.

For now, everything looks good. Great work. Thank you.

[donstim]

Thanks @aadee9940. I did not expect any testing on this yet, let alone within minutes of building it! I've converted it to draft until someone who can code (which does not include me) can change the CGs shown on the PFD and SD to be the same as that shown on the payload page of the EFB.

[aadee9940]

@donstim I have had countless flights diving to the ground after 30 mins of preflight, safe to say this issue is a bit personal hahaha😁

[aadee9940]

Test 2: Takeoff at 448T, EFB CG OF 40.6, FLEX 65, KMIA09, FLAPS 1+F, MSFS24

1. Auto-rotate issue = not seen here, all was normal. Nose stayed down and planted until VR of 156

2. Unrecoverable stall issue = not seen here, plane was very stable throughout rotation and initial climb. Although i will add, there was a small but sudden pitch up moment around 500RA. This could be low level turbulence as well so, not entirely sure.
   (Although not a "full stall" test, this does prove the aircraft does not enter a stall by itself ,which it did before)

Edit: Landing into Heathrow was uneventful, everything was nice and stable. I have never encountered issue #9399, so can't say if this affects anything for it.

Test 2 results were good, fixes are working.

[BlueberryKing]

Very cool!

[flogross89]

LGTM, excited for this!

[aadee9940]

Test 3: Takeoff at 394T, CG OF 38.6, FLEX 64, VOBL09L, FLAPS 1+F, MSFS24

Auto-rotate issue: Not observed, nose stayed planted till VR of 151.

Stall issue: Not observed, plane was stable and flew well from initial climb till I turned on AP1 at around 4000 AGL.

Landing was ok, no issues. I will also start testing the deeper CG/EFB/THS/PFD changes soon.

[aadee9940]

Testing CG/EFB/THS/PFD logic in MSFS24.

Consistency between EFB/PFD/SD:

Outside of green range, After pressing takeoff config:

TOGA:

FLEX:

Red master caution test:

Tested again with a GW of 500T, everything was working as expected.