SERVICE BULLETIN 16-08-01 (released Oct 1, 2016)

[engineerofsorts]

I ran the test-only took a whack or two to cause 1/8-th inch plus of displacement both ways. Removing and re-installing the horizontal stab--one of my favorite activities to allow me to review my favorite cuss words.

[RFSchaller]

This year I noticed some play in my stabilator. I feared the worst, but when I took the stabilator off what I discovered was that the paint shop had not put the shim washers back in after they painted. The paint layer was thick enough to center the stabilator in the hinge bearing. Over 5 years the paint wore away and I ended up with the small horizontal play (about 3/32"). It was just enough to cause the stab skin to rub against one fairing screw.

So if you fail the "Thump Test" it may not be a slipped bearing.

[RFSchaller]

Well, my bad! Mothership was right! I put the stabilator back on with the shim washers and the thump test failed again. I tapped the bearings with a nylon head tack hammer and they popped out. Looks like my well intentioned attempts to lubricate the joint only ended up wicking oil into the gap between the bearing and the socket it is pressed into.

I cleaned up everything with acetone and alcohol before applying the Loctite recommended in the SB. Hopefully the issue is resolved.

[rv9builder]

Originally Posted by RFSchaller

Well, my bad! Mothership was right! I put the stabilator back on with the shim washers and the thump test failed again. I tapped the bearings with a nylon head tack hammer and they popped out. Looks like my well intentioned attempts to lubricate the joint only ended up wicking oil into the gap between the bearing and the socket it is pressed into.

I cleaned up everything with acetone and alcohol before applying the Loctite recommended in the SB. Hopefully the issue is resolved.

Hi Rich,

Have the bearings been holding in place since you did the service bulletin? My kit is still under construction, and I'm just about to rivet the bearings into place. I've been debating whether to do the service bulletin on the bearings I have or just buy new bearings. The bearings that shipped with my kit seem pretty tight, but I wouldn't install them without complying with the service bulletin.

Has anyone else added Loctite per the service bulletin? How did it work out? The fit between the VA-146 flange and the bearing is so tight, it's hard to see how the bead of Loctite works its way in between them, but I guess it must wick into place.

[cyamaha2007]

Loctite retaining compound works great, at work we use it for bearings and press fit components that have tolerance stack up causing too loose of a fit. If it were me I'd put loctite on the bearings and rivet it. I don't see any reason not to.

[RFSchaller]

6 months later the bearings are still fine after adding loctite.

[rv9builder]

Thanks, Rich and Chuck.

[Charlie12]

I actually had the bearings slip sideways enough to make the HS skin rub against the left side tailcone skin. It happened soon after assembly, before I even made my first flight. I whacked the end of the spar pretty hard with my hand to knock it back into place and then called builder support to ask for guidance. They told me to try the Locktite thing and after 67 hours it still is centered. I did file off the edges of the HS skin to get a little more clearance while I had it off. The SB sounds an awful lot like my phone conversation with builder support and was issued just a few weeks later.