SV-42 Servo backlash

[AlanR]

Bristell NG5 ... 3years old. 200hours.
On a nil wind benign day with autopilot engaged, straight and level tracking a flightplan, I have recently noticed that the aircraft sets up a gentle side to side rocking motion which I have never noticed it previously doing and after a while it gets on my nerves and I disengage the autopilot.
I have checked for play and slop in the aileron linkage and there is none as you would expect in a nearly new aircraft however there seems to me to be excessive play in the SV-42 aileron servo itself . The play is not between the arm and backing adaptor but seems to be in the servo itself like gear backlash or worn bushing.
Is this some play ( backlash) normal do you think ?.....and if so is this what is causing my 'rocking' motion?
There does not seem to be this amount of play/backlash in the SV-32 pitch servo.
Or am I completely on the wrong track with this and maybe need to adjust Roll settings, i.e reduce Roll sensitivety?
Thoughts required please...

 

[XPRSAV8R]

This happened to me. I was advised to recalibrate the ADAHRS on the ground and in-flight. This fixed it for me.

 

[AlanR]

Thanks.
Not quite sure what you mean by recalibrate the ADAHRS?..Can you explain please?
Do you mean re-configure the ADHARS which as I understand is configured or is not on the ground and the PFD would not work correctly if not configured? The only adjustment in settings for the ADHARS is for baro and altitude offset that I can see.
Or do you mean Test/re-Calibrate the Autopilot Servos?..which I have tried and makes no difference.

 

[Raymo]

Sounds like you may have a broken shear pin in the servo.

 

[WmInce]

Sounds like you may have a broken shear pin in the servo.

x2

 

[AlanR]

I am pretty sure the shear pin is not broken because the play/wear is actually in the servo...between the spindle and the internal gears and not between the operating bracket and plate which houses the shear pin.
What I really want to know is, is movement or backlash in the servo gear normal?... I only have the pitch servo to compare it with and that has very little or no backlash in it.

 

[Raymo]

What I really want to know is, is movement or backlash in the servo gear normal?

No, there should be no play in the servo.

 

[AlanR]

Thanks, that is what I think. I'll wait until after Oshkosh and then get in touch with Dynon directly.

 

[JCMM]

Same on here...
I've checked the shear pin and it is ok..

 

[DBRV10]

There is always a small amount of backlash, but it might be worth considering your roll settings too. Sensitivity too high will do a similar thing.

 

[neottHout]

Curious question

 

[Douglas]

I have the exact same issue with a Cessna 172. I would love to solve the problem. I was returning Sat on a short cross country and the damn thing nearly rocked me to sleep
I would love to find a solution fast!