manual aileron trim won't hold

floydpackard · #1 08-24-2008, 10:49 PM

How do I tighten the manual airleron trim. When I am in cruise flight the airleron trim slips back to neutral. It seems like I need a little more friction.
Thanks
Floyd

DickDe · #2 08-24-2008, 11:12 PM

The UHMW plastic bearing block the trim lever shaft is mounted through and pivots in is a block with a hole drilled in it & one side is split. A bolt across this split is tightened to add friction to the shaft. You will have to lift the seat pan which also covers the aileron control tubes in the fuselage to get at this block. It is a very simple mechanism and it won't take much of a turn to tighten the friction...maybe a 1/16th of a turn.

Dick DeCramer
RV6 N500DD 300 hrs
RV8 wings almost done
Northfield, MN

Jimd · #3 08-25-2008, 06:17 AM

I have experienced this trouble on two different RV's and am about to install my own for the inspection and wonder if splitting the other side would help any? Or, what about putting a little valve grinding compound in the block saddle at assembly to add some grit?

Webb · #4 08-25-2008, 06:23 AM

One pass through the bandsaw isn't wide enough. Take it out and run it through again. It will tighten up nicely.

Noah · #5 08-25-2008, 11:05 AM

Webb is right. Depending on the width of your saw kerf, the edges of the slot may contact when the bolt is tightened, thereby limiting the resistance. Widen the kerf in the UHMW, and tighten the bolt some more. Should be able to get all the resistance you need.

sprucemoose · #6 08-25-2008, 11:56 AM

Webb and Noah may be right, but I doubt it. Chances are the kerf sides aren't touching, and if they are not, then simply tightening the bolt will do it. If the kerf is bottomed out then you will have to widen it, but don't do this unless you have to.

The UHMW blocks do wear over time and eventually you might have to widen the cut, but with the amount of hours on that particular plane, I seriously doubt it.

Always check the simple, cheap stuff first.