View Full Version : L500/VBAR and tic-toc Tail Precomp questions
08-19-2010, 05:50 AM
L500, 6S 5000, VBAR 4.0
On elevator tic-tocs, nose rotates right/clockwise. To start I had:
Zero Pitch: 0
I then tried:
Zero Pitch: 0
Sens. Deadb.: 3
RC Deadband: 3
Stop Gain A/B: 20
Cyclic Gain: 100
Cyclic Ring: 75
Pitch Pump: 30
This appeared to help some. Should I increase both Collective and Cyclic values to solve the problem and/or change other Tail Rotor values?
Thank you for sharing your experience.
08-19-2010, 06:15 AM
You need to increase the pre-comp valeu for collective instead of cyclic. Try something like 16 on collective and 8 for cyclic. Do some full pitch climbouts and watch the tail, if it moves counter clockwise and back to the right spot when you stop the climbout you need to increase the pre-comp for collective a little more, if it moves clockwise and back then you have too much. The value for cyclic pre-comp is not as essential and you are better of having too little then too much. Too much would cause the problems like you are describing when using cyclic will offset the tail. Genarally 1/3 to 1/2 of the collective value should be about right. I suggest you stick with half, if you find the tail (or nose) acting weird and moving clockwise on tic-tocs or flips and rolls you need to reduce it.
P and I gain in most cases works best at default, but if you have a very specific issue like in piro figures you could start tweaking those.
Sensor deadband for the tail works the most accurate at 0 but this also stresses the servo a little more, I kept mine at 1 which reduces the servo buzzing a bit but still more accurate then 3.
08-19-2010, 07:17 AM
Great information, thank you. I will make the changes and attempt again.
P, I, and Acceleration are the default values. So are the stop gains.
Would it be better to use the tail optimizer to set these values?
08-19-2010, 04:41 PM
The optimizer does some small tweaks on the tail I don't know exactly what it adjusts but it doesn't change the P and I settings.(if you really ned to know ask Mr.Mel) I think it improves the stops a little and maybe some other little things.You only need to run it one flight where you do your usual flying, hovering won't do it any good. Besides that just keep default, tune in the pre-comp, and if needed change the A and B stops you should get a pretty goed tail. If you find the tail response in general feel a bit soft and sluggish you can increase the accelaration value.
See how it goes and move on from there, don't change too much at once or you won't know how each setting changed the behavior.