Elevator trim wanders

[teeweed]

I read a post not to long ago about a stiff elevator trim. Someone said be careful not to oil the worm gear to much. I noticed the other day that I can trim up the plane and within 3 or 4 minutes my crank handle has moved a quarter of a turn. I trim alot and this must be the reason. I remember oiling the worm gear about a year ago because I thought the crank handle turn was stiff. I guess I oiled it to much! I have cleaned the oil off the threads but it still wonders. There is not much up and down play so I don't think its worn out. Is there something I could put safely on the threads to give it more friction without making it to hard to turn. Thanks Mark

[Cubdude]

We've had problems with the cable slipping on the pulley. The mechanic "fixes" it but after a couple flights it slips again. May be grease on the cable.

[Steve Pierce]

Get any oil and grease off the cable. Hold a rag over it while someone works the trim. Might try a new tension spring at the trim yoke or handle as these are the ones that put the tension on the cable. Never had one turn the jackscrew on it's own.

[RMREBOB]

As steve said I doubt that the jack screw is turning. I suspect that the cable is slipping on the pulley. The problem with the jack screw (and the pivot points for the horizontal) is almost alway not enough lubrication resulting in a stiff trim system. It sounds like you might have gotten a little enthusiastic with the lube on the jack screw and gotten some on the cable/pulley. Clean them and it will likely solve the problem.