RV-6 pitch servo over center

[Alco75]

Just installed a pitch servo (SV32) on an RV6 per the drawing and the servo arm goes over center and locks , seems to need a longer push rod but 6" is called out on drawing and supplied in the kit. Solutions?
Alan

 

[rvator51]

Do you have the push rod install in the most outer hole in the servo arm? If not, you could move it to the last hole to decrease the travel.

The other problem could be the hole in the elevator bell-crank could be in the wrong location?

 

[Alco75]

Two of us have checked the diminsions from the RV-6 install sheets, outer hole and 6" pushrod, bracket in correct location.
We need a longer pushrod to put the arm at 90 degrees to the pushrod, so changing holes won't help .
I had to customize the pushrod for the roll servo but it was too long,stretching them is much harder.
Guess I assumed the RV-6 instructions were very specific to that airframe, don't want to deviate from correct design too far.
Alan

 

[Robski]

The bracket for the servo has been fixed in the right place, hasn't it?
Not too far away from the bell crank?

 

[Alco75]

leading edge of bracket is 3.43" aft of the bell crank pivot. Still looking at possible airframe issues as the owner bought aircraft without any build info. A longer pushrod should cure it if no other causes are found.
Alan

 

[dynonsupport]

The dimensions shown on the installation guide are a starting point, but every airplane can be different. You should extend the pushrod so that over-center cannot occur.