COM 5-3 aileron bearing replacement outboard right wing

[DennisRhodes]

Anyone have a source for replacement of a COM 5-3 bearing( bushing)?. This is the pivot bearing in both inboard and outboard aileron on at least an RV9 maybe 7 and or 8 .

And possible repair method for installing. Looks like you can drill out the two rivets , separate the two sandwich halfs of P/N 914, insert a new bearing and re- rivet. Would certainly like to do this without removing the 914 bracket from rear spar. Comments appreciated.

 

[scsmith]

Anyone have a source for replacement of a COM 5-3 bearing( bushing)?. This is the pivot bearing in both inboard and outboard aileron on at least an RV9 maybe 7 and or 8 .

And possible repair method for installing. Looks like you can drill out the two rivets , separate the two sandwich halfs of P/N 914, insert a new bearing and re- rivet. Would certainly like to do this without removing the 914 bracket from rear spar. Comments appreciated.

Hi Dennis,
Vans sells the bearings. They are about $25 each. To help you with the search, its a COM-3-5. If Vans is back-ordered I have several in inventory because we use them in our Billet elevator and rudder hinges too.

But there are a lot more than two rivets to remove. You don't want to just remove those two and pry the two bracket halves apart - they are too stiff and you will bend other things. Here is a picture from the drawing (RV-8 in this case, but I think the assembly is common to all the 2-place RVs.)

 

[scsmith]

May I ask what happened to the original bearing? Hard to imagine they could fail in service, the rated loads are much bigger than our ailerons could ever apply. Rust?

 

[DennisRhodes]

May I ask what happened to the original bearing? Hard to imagine they could fail in service, the rated loads are much bigger than our ailerons could ever apply. Rust?

There was some unusual movement up and down on that end of the aileron. Disassembled to see what was going on. An3 bolt looked fine, washers all good. But the Com 5-3 bearing was "loose " between the two 914 sandwich plates. Hole size in bearing was fine, and bearing was free to rotate. Appeared to be no way it could escape the 914 bracket but just loose. I re squeezed the two rivets and corrected most of the movement. Re assembled with new hardware. Appeared to be OK for now . But thought I would find parts to one day replace that brng. Inboard looks good as well as both in and out on other wing. Does the 914 have same size diam hole on one side as the other?? Appears that maybe the brng being loose may have resulted in rotating in the bracket.

 

[scsmith]

There was some unusual movement up and down on that end of the aileron. Disassembled to see what was going on. An3 bolt looked fine, washers all good. But the Com 5-3 bearing was "loose " between the two 914 sandwich plates. Hole size in bearing was fine, and bearing was free to rotate. Appeared to be no way it could escape the 914 bracket but just loose. I re squeezed the two rivets and corrected most of the movement. Re assembled with new hardware. Appeared to be OK for now . But thought I would find parts to one day replace that brng. Inboard looks good as well as both in and out on other wing. Does the 914 have same size diam hole on one side as the other?? Appears that maybe the brng being loose may have resulted in rotating in the bracket.

It sounds like the bearing opened up the size of the pocket. Or the builder did because the pocket seemed too tight, and they over-shot and opened it too much. The clamping action of re-squeezing the rivets won't hold it under flight loads, it is still going to move around. The bearing can't escape, but it should be a tight fit in the pocket of the two halves of the bracket. My recommendation would be to replace the 914 brackets (both halves) with new, and a new bearing while you are at it. By the way, this type of hinge play can induce flutter at lower-than-V_ne speeds.

 

[DennisRhodes]

Thanks for your comments. I also believe the pocket has opened up allowing the brng to rotate. The one piece " looks " like it could be replaced. However I've got to evaluate that second piece and see how best it might be accessed. Maybe removing the wing tip might open up the back side for repair riveting.

 

[RV6_flyer]

Hi Dennis,
Vans sells the bearings. They are about $25 each. To help you with the search, its a COM-3-5. If Vans is back-ordered I have several in inventory because we use them in our Billet elevator and rudder hinges too.

But there are a lot more than two rivets to remove. You don't want to just remove those two and pry the two bracket halves apart - they are too stiff and you will bend other things. Here is a picture from the drawing (RV-8 in this case, but I think the assembly is common to all the 2-place RVs.)
View attachment 70856

It sounds like the bearing opened up the size of the pocket. Or the builder did because the pocket seemed too tight, and they over-shot and opened it too much. The clamping action of re-squeezing the rivets won't hold it under flight loads, it is still going to move around. The bearing can't escape, but it should be a tight fit in the pocket of the two halves of the bracket. My recommendation would be to replace the 914 brackets (both halves) with new, and a new bearing while you are at it. By the way, this type of hinge play can induce flutter at lower-than-V_ne speeds.

I had to replace the LEFT aileron bearings on my RV-6 because when I built the airplane, I had side loading on the bearings that caused the pocket to open up.

I replaced the old with all new parts except for W-413 assembly, I did not replace the W-413C-L or the W-413D-L because of the difficulty in replacing the rivets in the rear wing spar. Since the parts were "match drilled" by Van's Aircraft, everything lined up like the original build. Was able to lay the old parts over the new to check rivet hole locations before reassembly.

I did not use a lot of words to describe the replacement but new spacers were fabricated to remove the side load to prevent reoccurance of the "pocket opening up" again. The right side aileron bearings are still find after 27-years and over 3,600 hour of flying. Must have been tired when I did the left one during the rigging process.