Need help with Traditional Heli yaw PID



I'm trying APM2 on HK 450pro heli. I just did the test and the result, pitch and roll are alright, it was stable. The problem is with my yaw/rudder. I need to push my rudder to most right to make sure heli stays and basically I had no yaw authority.

I'm attaching the parameter file and the log file. Hopefully I can get a hint on which parameter I need to modify to get a better yaw authority.






2012-04-28 15-12 9.log

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  • Today my heli crashed again from testing the attitude hold and the only part that was damaged was the umbrella gear set at the front torque tube assembly again.  This time I used some cheap clone HK brand  and it is just not as smooth as the align one.  Since I got quite a few bags of them, I used it any way. 


    Then I tested it by just hovering.  It had quite a bit of vibration at the tail and it also randomly twitched.  I think it was like how you described yours.  I lowered the Yaw Rate P to 1.9 and lowered the Yaw Rate I a tiny bit to get rid of the vibration.  Then the tail wasn't holding still so I increased the Yaw Stab P to 2.5 and it took care of it.  However, the random twitching was still there.


    So I took the heli apart again and put in my last set of authentic Align umbrella gear and it's all smooth again.  I can increase my Yaw Rate P back up as well.  Is your tail belt driven or torque tube?

  • I think your RATE_YAW_P=0.6 is too high.  I've noticed that when certain Yaw numbers are too high, it'll overpower the control.  When it's too low, you have low/no control.


    When I used very well balanced blades, I could get my Rate Yaw up to 0.288.  I'm now using a set of not-so-balanced blades, the tail was wagging and I have to lower it down to 0.206.  


    My current Rate Yaw P=0.206, I=0.02, D=0.001, IMAX=50.  Stab Yaw P=2.2, I=0, IMAX=6.  It's a set of ever changing numbers.  lol.

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