fix(a380x/flightmodel): adjust climb performance

[BlueberryKing]

Fixes #9042

Summary of Changes

Tune engine thrust and drag model to be more accurate.

• Adjust performance in .cfg files
• Update engine performance tables for vertical predictions
• Update performance tables for flight model

Screenshots (if necessary)

References

Additional context

Discord username (if different from GitHub):

Testing instructions

• Perform a full flight, ensure you get (close to) accurate predictions throughout the flight.
• Ensure that the climb, cruise, and descent performance is believable.

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 or flybywire-aircraft-a380-842 download link at the bottom of the page

[chinjh93]

Tested some of the values you've amended the plane feels a bit sluggish at climb now. Gross weight of about 373tonnes and my climb was only 2000fpm during the climb from 10000feet to 15000feet with IAS 290knots on open climb. This value was more believable if the gross weight was around 500tonnes or more.

[BlueberryKing]

Tested some of the values you've amended the plane feels a bit sluggish at climb now. Gross weight of about 373tonnes and my climb was only 2000fpm during the climb from 10000feet to 15000feet with IAS 290knots on open climb. This value was more believable if the gross weight was around 500tonnes or more.

Thanks for testing! I noticed the same thing indeed, this was due to an error in my tuning method. I will continue to work on it.

[2hwk]

@BlueberryKing Let me know when you are done so we can do a formal code review

Also changelog needed.

[chinjh93]

Has the parameters been tested and merged with the supposed Another taxi thrust adjustment Cause i seem to see both pulls involve the same cfg.

[BlueberryKing]

Has the parameters been tested and merged with the supposed Another taxi thrust adjustment Cause i seem to see both pulls involve the same cfg.

My changes are now on top of the PR you mention, so they shouldn't conflict.

[donstim]

One test here and it looked very good to me. Although I don't have any data to base it on (other than comparison to the A32NX), the climb rates looked very believable. For my flight, FMS predicted FL 400 at REC MAX, and I got to FL 39.6 before the climb rate stayed below 300 fpm (one definition of REC MAX).

[flogross89]

Very cool, thank you!

[BlueberryKing]

Thank you for the reviews! I will address your comments as soon as I can.

[donstim]

Regarding taxi thrusts on the A380, in real life they use around about a maximum of 15% THR and no more that 15% THR, even at the MTOW. So according to real world A380 Pilots, they only use a small amount of thrust to get moving at very heavy weights.

This PR does not affect taxi thrust. Taxi thrust has already been adjusted with the assistance of IRL A380 pilots on the team. (The THR indication on the A380X is not accurately modeled yet.)

[BlueberryKing]

I have made some further adjustments to the thrust output and thrust limits. The thrust output might be a bit too high at high altitudes now, but I prefer that for this initial adjustment PR.

Feel free to give it a test!

[alexr4339]

Quality Assurance Tester Report

Discord Username : alexdnzdmb
Object of testing : #9358
Aircraft : A380X
Tier of Testing : 1
Date : 25/12/2024

Testing Process:
Takeoff and compare estimates/actual and simbrief, then descend and land

Flight 1:
509T (41.5%) ZFW 334T (36.6%)
Simbrief | Pred (FMS) | Act
DF149 3400 | 4400 | 3700
(Switch to STD Baro 30,59 to 29,92)
DF151 6100 | 6700 | 5900
DF167 ---- | 11600 | 11800
DF169 13400 | 13100 | 12500
AGOLO 18500 | 19100 | 17500
(Had 2 of 4 engines at idle for around 10-20s due to sim awakeing after sleep mode, which caused plane to stop climb)
OKTUM 21700 | 22800 | 20700
KOMIB 24200 | 25600 | 23700 (1600 fpm climb)
SULUS 27400 | 29300 | 27700 (1300 fpm)
TONSU 30000 | 32300 | 30800 (900 fpm)

THR IDLE DES
Descend at FL300, 290 KIAS: -2900
FL250, 290 KIAS: -2400
FL150, 290: -2000
Fl100, 290: -2000
Fl050, 250: -1400

Testing Results:
Passed

Negatives:
None

Conclusions:
It does feel like an A380 now. Much improved climb performance (improved in terms of feels closer). FMS pred being off was probably due to no wind being inserted in the FMS

Media:

[mattking247]

Quality Assurance Tester Trainee Report

Discord Username : Matt
Object of testing : #9358
Aircraft : A380X
Tier of Testing : 1
Date : 26/12/2024

Testing Process:
Full flight OMDB - EGLL, full departure from OMDB Rwy 30R with calm weather.

Notes:
505 tonnes at take off.

Various takeoffs and climbs at light and heavy weights.

I think this feels as much like an a380 now as I can tell, without jumping in an FMS and doing a direct comparison. I think it is close enough that it feels right. Acknowledged about the THR vs N1 discussion and derates. However, as an interim before they are addressed, I think it feels really good.

I would say this QA passed.

[aadee9940]

Currently doing a flight from VHHH TO OMDB, and the engines are running at a constant 95% thr just to maintain airspeed. Any attempt to step climb does not work.

Climbing from FL380 TO 400 at 350 tons is proving to be an impossible task.

Because of the engines running at a constant 95% THR, fuel consumption is also greatly increased, and it looks like I am not going to make it to Dubai. :(

Never had this behavior before though, from the few flights i have done, the engines run at around 80-85% THR.

This is one flight though, it may not occur with others..
Thanks.