Posted by jb92563 on Tuesday, February 21, 2012 @ 02:30 PM:
My elevator belcrank has some side to side play.
Has anyone replaced its bearing?
What is it, a bushing, ball bearing?
Any tips for fixing it?
I reached in to the fuselage behind the seat with the Iphone and snapped a couple pics.
Does not look too hard to remove.
Just remove the one pivot bolt, the elevator pushrod connections and then it should come right out?
--------------------
Posted by eugenio on Tuesday, February 21, 2012 @ 03:22 PM:
It's a bushing. If you tighten the bolt it will stop tilting.
Eugenio
Posted by jb92563 on Wednesday, February 22, 2012 @ 11:36 AM:
I'll give that a try and tighten the bolt a bit.
If I tighten it is there any danger of binding?
I'd rather have some lateral play than binding.
Thanks Eugenio
--------------------
Posted by eugenio on Thursday, February 23, 2012 @ 03:25 PM:
Tighten until the bellcrank stop tilting. If id does not, you should remove the bolt and slightly shorten the small pipe on which the bushing rotate. The bolt should be a 6mm one with a 6x8 mm tube on which the whole system rotate. The tube must be firmly clamped between the two plates and absolutely should not rotate. If you have too much side play the bellcranks tilt. The sides of the two bronze bushing should be clamped between the two faces of the support plates with the minimum side play to let the bellcrank rotate freely.
The only danger is to crush the plywood, so be careful.
Eugenio
Posted by jb92563 on Thursday, February 23, 2012 @ 07:45 PM:
Just to be clear, the side play, is not just a pure lateral movement but an actual tilt at a small angle.
It sounds like it is basically a bushing riding on a tube with the bolt going though it.
The bit of angular movement probably suggests that my tube and or bushing have worn down enough to allow some tilting.
About 1/4" shimmy at the top of the bellcrank
Perhaps the bushing has worked loose in the bracket?
Quite possible in the dry sandy dusty south west of the US where the RF4D has spent much of its life.
I think I better remove it soon and take a good look at what needs replacing.
Ray
--------------------
Posted by eugenio on Friday, February 24, 2012 @ 01:27 PM:
First try to tighten the bolt.
Anyway a common problem in all Fournier's bellcranks (the same system is used on midwing bellcrank and in the aileron one) is that the tube sticks to the bushings and instead to have the bushings rotating over the tube is the tube that rotate over the bolt. In this case you have to remove the bolt, the tube, the bellcrank, clean everything and check all plays.
Eugenio
