Considerable amount of pitch trim required except for F-18

1st Official Post

    The F18 control model has excellent flight characteristics as well as minimal pitch trim required while most of the other aircraft require it frequently. It becomes difficult to fly smoothly unless pitch trim is adjusted often due to changes in aircraft speed or configuration change. I just wonder why the F-18 doesn't require much - it's almost as if there is automatic trim

    Thanks for an amazing flight sim

    Dave

    Makes sense. The real thing is FBW and auto-trim.

    The power and configuration changes in any aircraft not having a stability augmentation system ( SAS ) asks for trimming - that's as real as t gets :)

    I believe the A320 should also require less trimming than most other aircraft models. I don't recall right now if the one in AEFS2 shows that characteristic too.

    Main Simulation Rig:

    Ryzen 5600x, 32GB RAM, Nvidia RTX 3060 Ti, 1 TB & 500 GB M.2 nvme drives, Win11.

    Lenovo TB310FU 9,5" Tablet for Navigraph and some available external FMCs or AVITABs

    Both are FBW planes and e.g. the A320 never requires any pitch trim input. In normal law you can't even trim the A320.

    • Official Post

    In short, to answer your question: Yes the F18 has autotrim but the A320 as well.

    All other airplanes in the current Aerofly FS 2 fleet have no automatic trim modelled. Their trim will be set for takeoff when you select the runway starting position, they will be trimmed for level flight if you place it in the air and they will be trimmed for landing when you set them to the final approach through the "Location" dialog. If you have an analog axis assigned to the pitch trim though this preset will be lost immediately.


    The A320 flight augmentation system trims the real world A320 constantly to maintain a flight path vector and the real F18 flight controller trims the aircraft maintains a trimmed hands off 1g flight.

    Currently the Airbus A320 and F18 in the Aerofly FS 2 zero the pitch rate when the stick input is zero. Ergo they auto-trim the pitch axis to maintain zero pitch rate when the stick is released and therefore do a tromendeous job in maintaining the attitude you put them in.

    Now when you fly with a bank angle greater than zero then the A320 IRL and in the Aerofly FS 2 will try to compensate the additional nose up needed, up to 33deg of bank. The F18 on the other hand doesn't add any pitch input in a turn, you will need to trim it for a constant turn with more than 1g.

    Cheers,
    Jan

    @Senior Members,
    First off, I want to say that it is wonderful to have experts involved in the design and development of the FS2 simulator! The quality really shows and it is exciting to be able to show off this simulator to actual pilots using Virtual Reality equipment and have them come away feeling extremely impressed with the reality. Even though FSX/Prepar3D has some excellent terrain from ORBX and photorealistic vendors, it never feels fluid because the "ancient" code just can't provide a smooth enough update rate - especially in VR. No amount of ATW/ASW interpolation can make up for slow update rates.
    My comments about pitch trim probably are reflected in the fact that my Thrustmaster HOTAS.X joystick has too much mechanical deadzone which makes careful movements about the center difficult unless I am very close to being in trim. I really like the separated throttle and joystick though with enough buttons for system control. I also can use voice commands if necessary. Perhaps I need to try more expensive joysticks that would have better switches for pitch trim and a higher precision around center stick.

    Thanks again for the excellent flight sim - this is actually a better experience for me than my multi-million dollar Boeing airliner sims that I helped develop in Seattle.

    Dave

    Quote from Jet-Pack

    The A320 flight augmentation system trims the real world A320 constantly to maintain a flight path vector


    It's really complicated in the A320 because above 250kts you induce a load factor demand with the sidestick (the A320 also basically maintains 1G).
    Below 250kias IIRC C*law starts to blend in. And during the flare you are in direct law...

    • Official Post
    Quote from bbrz

    It's really complicated in the A320 because above 250kts you induce a load factor demand with the sidestick (the A320 also basically maintains 1G).
    Below 250kias IIRC C*law starts to blend in. And during the flare you are in direct law...

    Yes that is also true. I was referring to hands off the sidestick, autotrim due to config or thrust changes. Now currently the A320 in the Aerofly FS 2 doesn't model the load factor command under the pilots seat yet as we need to do more research on how exactly it fades from pitch rate command to acceleration command. The F18 already has something similar modelled, there I just check which pitch rate command is smaller because for low speeds its not possible to reach full 7.5g even at full elevator deflection.
    Where did you get the information that the Airbus blends over at 250kt and can you please share that source with us? Thanks!

    Cheers,
    Jan

    Quote from Jet-Pack

    Where did you get the information that the Airbus blends over at 250kt and can you please share that source with us?


    Just browsed through my airbus docs but found only handwritten notes I made when I asked an Airbus instructor during the type rating.
    Btw, this is about the best (and most expensive) pdf about the Airbus FBW.
    http://www.tandfonline.com/doi/abs/10.1080/00207179408923072
    PS: Approx 90% of the Airbus pilots in my company don't even know that there's a C*law....and you definitely don't need this info to operate the A320 I might add...