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Weird behaviou at rolling... Just before takeoff.

Scheduled Pinned Locked Moved PA-28R Arrow III
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    Paul J
    replied to sdvpilot on last edited by
    #16

    @sdvpilot: longitudinal phugoid oscillation

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    Dustin
    replied to sdvpilot on last edited by
    #17

    @sdvpilot said in Weird behaviou at rolling... Just before takeoff.:

    @ViniciusQdrs Yes not a skid but a sudden yaw left or right just reaching takeoff speed on some but not on every takeoff with no significant crosswind. Don't know what the cause might be but it was not always that way until one of the latest updates. It is like a sudden wind gust hitting the vertical stabilizer just when you leave the ground.

    I seem to be experiencing this as well.

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    tatar
    wrote on last edited by
    #18

    There is one thing I can't understand. In flight-model.cfg for c172 moments of inertia are 3 times grater than in case of arrow - but both planes have similar mass. Is such a difference really possible or maybe default planes have this paramer tuned up to get more stable behaviour? Am I missing something here?

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    Delta558 Developer
    wrote on last edited by Delta558
    #19

    I cannot speak for what was done with the default aircraft, but the Arrow's MOIs have been calculated as per standard aerodynamic convention.

    Just Flight FDE developer

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    ViniciusQdrs
    wrote on last edited by
    #20

    These videos shows the "bug"...

    https://www.youtube.com/watch?v=u_VErEHjZXY - this one shows perfectly!
    https://www.youtube.com/watch?v=2PEfNZGwh8Y
    https://www.youtube.com/watch?v=xOf_b6tonjs

    Vinicius Quadros
    Lawyer. Virtual Flight Simmer. Lover of visual flights and piston aircrafts.
    i7 10700kf | RTX 3070ti | 32gb (4x 8gb) | 2x SSD (1x 480gb / 1x 240gb).

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    Delta558 Developer
    replied to ViniciusQdrs on last edited by
    #21

    @ViniciusQdrs And that first video - I have seen that behaviour in default aircraft, I actually have not seen it to anywhere near that extent in the Arrow except for when I adjusted the yaw stability setting to =1 (as recommended above).

    It is a problem with the sim.
    The weather builds the crosswind effect from nothing when stationary to full effect at about 50kts. Unfortunately, you are also entering the transition period in this aircraft between the sim's ground handling and airborne handling, which also deal with weather seemingly differently. There is a lot going on in the core sim at around that speed.

    A quick search of the MSFS forums throws up thread after thread about this, virtually every aircraft is affected by it (some say not the airliners, others say even they are). Until the core sim is sorted, anything we try and do is going to be at best a botched job that may have detrimental effects elsewhere.

    Just Flight FDE developer

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    sdvpilot
    replied to Paul J on last edited by sdvpilot
    #22

    @Paul-J Yes that is it, and it is quite bad on initial climb. Greater than +/- 500 FPM, but it does seem to eventually settle down.

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    sdvpilot
    replied to Delta558 on last edited by sdvpilot
    #23

    @Delta558 Good to know it is in the sim. It gets almost uncontrollable with any kind of crosswind.

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    tatar
    replied to Delta558 on last edited by
    #24

    @Delta558 I think it is better with sensitivity settings you recommended, but still you cannot stay on the ground any moment longer than nesessary. I tried also yaw stability set to 0.05 and I think it helps, but i did only few takeoffs with this setting yet, so I have to do more testing. It was ok, but maybe wheather was too mild.

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    copper
    wrote on last edited by
    #25

    Have the same issues, also when doing a Touch&Go, totally uncontrollable as soon as I'm touching the ground, sliding left and right.
    Control sensitivity is on default, no issues hand-flying or taxiing at all, only at high speeds.
    And since this has not been the case before the recent updates, I don't think this is just a MSFS issue.

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    Cristi Neagu
    replied to copper on last edited by
    #26

    @copper It really is a sim issue. Been having it for ages now on the DA-62.

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    copper
    replied to Cristi Neagu on last edited by
    #27

    @Cristi-Neagu said in Weird behaviou at rolling... Just before takeoff.:

    @copper It really is a sim issue. Been having it for ages now on the DA-62.

    But didn't have it with previous versions of the Arrow, there was defintely some change in the recent updates that made it far worse. Never had such big issues to counteract wind on takeoff roll. Doesn't happen on other aircraft this way to me, so there certainly is a way to avoid this.

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    Delta558 Developer
    replied to copper on last edited by
    #28

    @copper There have been various issues with the rudder through development, testing and with all versions released so far. Each attempt to improve things seems to throw up or increase another problem area.

    Let me be clear, I am not happy with it.

    I do not rate the core flight model at all - I think it started with good intent but the implimentation is poor. Within that, I think that the yaw axis is by far the weakest of the primary axes. The problem is, the same issues occur in the default aircraft, and we seem currently unable to just 'make it all work', we can fix some but not all. That is down to a poorly implimented core sim flight model which is brand new but has no worthwhile documentation .

    Just Flight FDE developer

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    copper
    wrote on last edited by
    #29

    @Delta558 said in Weird behaviou at rolling... Just before takeoff.:

    Let me be clear, I am not happy with it.

    Fair point, neither am I and I understand that tweaking one thing will break something else.
    Just wanted to say that the issue discussed here definitely changed to the worse for me in the last few updates (probably with 0.5.0).
    If that's the state that you think is the best compromise for now in terms of other effects, I can't contradict since I don't have all the insight :) But at least it's good to know that these issues are seen by the devs.

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    sdvpilot
    replied to copper on last edited by sdvpilot
    #30

    @copper I am in complete agreement with you that something has changed. I do not understand why it is not also obvious to the developers. While it may not happen on every takeoff, it does happen most of the time in fair weather with very light winds reported. I would go back to 0.3 to check but I really don't want to mess things up in doing so. It seems that I am spending most of my flying time just keeping up with updates and chasing bugs.

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    pvanderv
    wrote on last edited by
    #31

    I struggled with same problem but since upgrade 5.0 takeoff with cross wind does work very well. I also fly this plane in elite simulator. The behavior of the JF plane is close to elite counterpart . At a certain moment I was so desperate that I reinstalled windows 10 and fs2020 from scratch without succes; but update 5 made me happy again. Things went wrong after WU 4.
    The JF guy’s does a great job, thank you anyway.

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    ViniciusQdrs
    wrote on last edited by
    #32

    This issue wasn't on the previus versions of arrow...

    Vinicius Quadros
    Lawyer. Virtual Flight Simmer. Lover of visual flights and piston aircrafts.
    i7 10700kf | RTX 3070ti | 32gb (4x 8gb) | 2x SSD (1x 480gb / 1x 240gb).

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    lennsch
    wrote on last edited by
    #33

    same problem for me, also with no wind: https://www.youtube.com/watch?v=lKGjLDxfIkI&t=5s&ab_channel=PS4

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    copper
    wrote on last edited by
    #34

    For me the effect kicks in at 70kt IAS and is usually to the left. No wind, stable takeoff roll with basically no rudder input, but suddenly at 70kt there is a hefty effect to the left.
    Not an issue of weight&balance either (added copilot weight).
    Do not see this behavior with any other aircraft so far.

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    PilotJon
    wrote on last edited by
    #35

    Yes, at about 70 kts, I get a severe pull to the left and then a lot of swaying until I get off the ground...

    MSI Pro Z790, Intel i9 13th Gen 13900K, nVIDIA GeForce RTX 4090, 32GB DDR5 RAM, 2 TB M.2 Gen 4 SSD

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