Home Forums Everything about the Tricopter LR Tricopter LR uncontrollable spin on takeoff [SOLVED]

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    I finished building my Tri LR and am starting the setup procedures.

    I’ve setup everything according to Davids video and everything seems to work.
    Motor directions etc all fine.

    Did the servo calibration on the bench and that seemed to work.

    I setup autotune on a switch and am ready for the first hover to tune the tri.

    However, as soon as I go into a hover it keeps rotating (yaw) clockwise.
    I did all the servo setup stuff according the the video (setting angles, midpoint etc)

    Did I miss a setting somewhere?

    • This topic was modified 9 months, 2 weeks ago by PeterPankras.

    There are a few possibilities here…

    1) Servo is setup backwards in dRonin so instead of countering the Yaw torque it makes it worse. This can be verified by “flying” the copter without props while manually (your hand) causing the copter to Roll / Pitch and Yaw. The motors and Servo should fight against the changes to the copters orientation. Otherwise you’ve a setup issue.

    2) PID base values are either too high or too low. Ideally, you want the copter to have the lowest PID values that will still allow for you to have control. This will make tuning easier and help prevent oscillations. After the autotune has completed, the software will adjust the PID’s to levels that are reasonable, based on how the copter responded to the autotune process. Too much oscillation due to extreme PID values can make for a really bad tune.

    3) Servo “Center” is off or there is a significant amount of slack in the Servo travel.

    4) Copter FC orientation is off somehow and needs to be set / saved in dRonin.

    5) Yaw D-Term, set this to Zero and only adjust this upwards in small increments after your satisfied with the rest of the tune.



    I will check when I’m at home.
    The servo “fights” the orientation so don’t think that is the problem, also as far as I can see it compensates to the right direction.
    There is no play in the tail setup. It’s smooth as butter 😀

    The servo centering setup felt a bit weird. But I think it is correct. Did it the way David shows in DRonin in the video.
    After I set the min and max travel, I set the center. After I apply and save the settings the servo tilts to the laft (looking from the rear) it seems as it is anticipating for take off.. makes sense if it is tilted a bit before takeoff.

    The FC orientation is correct.. but I will align it again just to be sure.

    Yaw D-Term I haven’t checked yet.. don;t know what the default value is as I haven’t touched it yet.

    I will get back after the next checks 🙂


    does the servo fight the orientation or the propwash? it is often misunderstood what the servo on a tri should do and your description sounds a lot like the servo is doing the wrong thing. this is what it should do when you move the tail to the left (and on my TriLR I had to reverse the servo):

    • This reply was modified 9 months, 2 weeks ago by wov.

    “After I apply and save the settings the servo tilts to the laft”

    This is incorrect, as the trim position should be tilted slightly to the right, assuming you are using the stock prop rotations on each motor.

    My bet is the min/max value for the yaw servo need to be reversed, the larger number should be the min, the smaller the max, effectively reversing the servo.


    Wait indeed.. I think I need to reverse my yaw servo the more I think of it.

    I have another problem with DRonin.

    I used the version in this thread https://rcexplorer.se/forums/topic/dronin-installers/

    But now windows defender removed because it sees a possible virus.

    I downloaded the latest release from github, but when I use that one it sais that my firmware does not match the version of Dronin.

    Should I just reinstall the version from the forum?


    You need the forum version as the dronin github version does not support the KakuteF4V2 or triflight.

    You may have to create an exception in the virus program, some are likely to flag the GCS as a virus, some are not.


    Thanx Guys!

    Reinstalled the forum version of dronin so I could read the FC settings again.

    I reversed the yaw servo.

    Went outside and took off!
    Had to get a bit used to the feeling.
    Then switched to autotune and was able to keep it in the air while it was measuring.

    Landed, went inside. Connected the FC and it read in the autotune settings!
    Saved et voila.

    So it flies great so far. Currently testing and dont have a VTX and camera installed.
    Don’t have the lipo yet I want. So testing with a 3s 3000 for now.
    Plan on gettings 3s 5200’s like davids setup.

    Let the adventure begin!

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