Twitchy Rudder (not just an MSFS issue)



  • After flying Robert Young's Bonanza Turbo V3 mod for a bit, I find coming back to the twitchy rudder on the Piper Arrow frustrating.

    I know it's been said (and appears to be generally accepted) that this is an MSFS issue but the Bonzanza Turbo v3 mod handles beauitifully on the ground and in the air. What Robert has achieved there shows what can be achieved within the limitations of MSFS.



  • Here are some recommended changes to the flight_model.cfg file that will improve the "Twitchy" rudder behavior during the takeoff and landing roll. The changes to the rudder parameters also improve yaw control and stability in flight, and improve handling and yaw control during crosswind takeoffs and landings.

    The changes to the landing gear parameters will also improve the taxi steering and overall ground handling. And, reduce the tendency to bounce on touchdown...

    [CONTACT_POINTS]
    max_speed_full_steering =20 ;10
    max_speed_decreasing_steering = 40 ;20
    min_available_steering_angle_pct = 0.05 ;0.2

    ;point.0= 1, 6.6, 0, -2.96, 1181.1, 0, 1.221, 20, 0.106, 2.4, 0.694, 3.8, 3.9, 0, 129, 129, 1
    ;point.1= 1, -1.38, -5.1, -2.94, 1574.8, 1, 1.523, 0, 0.24, 1.5, 0.268, 5.7, 6, 2, 129, 129, 1
    ;point.2= 1, -1.38, 5.1, -2.94, 1574.8, 2, 1.523, 0, 0.24, 1.5, 0.268, 6.4, 6.8, 3, 129, 129, 1
    point.0= 1, 6.6, 0, -3.06, 1181.1, 0, 1.221, 30, 0.206, 2.4, 0.694, 3.8, 3.9, 0, 129, 129, 1
    point.1= 1, -1.38, -5.1, -2.94, 1574.8, 1, 1.523, 0, 0.24, 2.0, 0.9, 5.7, 6, 2, 129, 129, 1
    point.2= 1, -1.38, 5.1, -2.94, 1574.8, 2, 1.523, 0, 0.24, 2.0, 0.9, 6.4, 6.8, 3, 129, 129, 1

    [FLIGHT_TUNING]
    rudder_effectiveness =0.1 ;0.7
    rudder_maxangle_scalar =1 ;0.5
    pitch_stability =0.15 ;0.1
    roll_stability =0.15 ;0.1
    yaw_stability =0.15 ;0.1



  • @RetiredMan93231 Awesome, thanks very much for that. Changes made and looking forward to the improvements 🙂



  • @RetiredMan93231 Sweet! Cant wait to try these. Thanks RetiredMan.



  • @BernieV Let me know how this compares to the real world aircraft ground handling and landing performance, as well as the in flight rudder authority...



  • @RetiredMan93231 Much better. The effectiveness of the rudder pedals has improved. It feels more realistic in terms of rudder pedal travel required. I setup a 17 knot crosswind and landing was relatively easy. Crosswind takeoffs at 17 knots were a bit less predictable. My first attempt resulted in a 20 or 30 degree lurch to the right (into the crosswind). I think I may have held it down a little long. On the next attempt, with max crosswind takeoff I got airborne around 65 knots and handling was about what you'd expect. Still a bit of side loading on the gear, but that's pretty close to my real life performance in strong crosswinds (lol).

    All in all, you parameters yield a significant improvement in realism and usability of the model. Thanks!



  • @BernieV , Thanks for the great detailed feedback... try reducing the rudder_maxangle_scaler to around 0.75 and see if that feels closer to normal for crosswind takeoff and landing. The current setting of 1.0 allows for a significant amount of yaw and sideslip, maybe too much!

    I just tested it again with a rudder_maxangle_scaler setting of 0.75 and that is enough to perform a 20 degree sideslip... and to land with a 17 knot crosswind. So, I think a value of 0.75 or 0.80 is going to be about right for this parameter.



  • @RetiredMan93231 THANKS for your work. Awesome



  • @BernieV said in Twitchy Rudder (not just an MSFS issue):

    My first attempt resulted in a 20 or 30 degree lurch to the right (into the crosswind).

    Crosswind takeoff in this aircraft is a bit tricky, because at slow speeds the nosewheel steering has much more control over the direction than the rudder, and the nosewheel can turn up to 30 degrees with full pedal input. The max nosewheel steering angle reduces as the speed increases up to about 40 knots, and the rudder then has more control. The rudder also gets more effective as the speed increases. Also, since this aircraft does not have springs on the nosewheel like a Cessna, it doesn't transition from nosewheel steering to rudder steering as smoothly as a Cessna does.



  • @RetiredMan93231 Your settings did improve the feel of the rudder in all conditions. Unfortunately nothing can fix the FS transition from ground to air. Was holding the centerline easily up until about 60kts, when the plane violently yawed to the right into the wind. Let's hope Asobo fix this.



  • With these modified settings I get some weird yaw oscillations even as the wings are kept level. It is most noticeable just before landing in a slight crosswind. I haven't done extensive testing but I have verified it isn't present with the default settings.

    I suppose this is something to do with yaw_stability, but I'm not sure