Elevator Attach Rod End Adjust

[jwilbur]

To get my left elevator to swing the required 30 degrees up and 25 down without the rolled forward edge touching the HS rear spar, I have to back out the rod-end bearings 2 full turns. They could have been in a half turn too far to begin with (it's tough to be sure of that measurement and I favored too much rather than too little) so maybe it's really only 1.5 turns that I backed out from ideal.

I'd like some thoughts on what is safe here. Assuming a person has them set exactly according to the plans, how much backing out is too much?

 

[CharlieWaffles]

I believe the general rule is the bearing should have no more than half the threads exposed. You may be able to tightened the aft bearing and loosing the fore bearing a turn to get the required spacing without one or the other bearings being out too far.

 

[paul330]

As I understand it, the "half-the-threads" rule is for a control rod so that if it turns, you can't back out one of the fittings. I believe Joe is talking about the fittings that screw into the rear elevator spar. These can't back out as the bearing/bolt through the elevator prevents any possible turning.

I would say that, provided it's not just held on by a couple of threads and there is a reasonable depth, it would be OK.

 

[RV10Rob]

I had a similar issue and was concerned, as well. There really isn't much "extra" length on the threaded portion of those bearings. I called Van's, and they said it was fine as long as the threads are completely engaged in the entire nutplate. I ended up using a scope to verify this. Mine was fine, but just barely.

-Rob

 

[jwilbur]

I had a similar issue and was concerned, as well. There really isn't much "extra" length on the threaded portion of those bearings. I called Van's, and they said it was fine as long as the threads are completely engaged in the entire nutplate. I ended up using a scope to verify this. Mine was fine, but just barely.

-Rob

Thanks Rob. This is the information I needed.

 

[Wayne Gillispie]

Mine are fine at 1.5 turns out.

 

[jwilbur]

What I ended up doing ...

I thought I'd share what I ended up doing here in case it might help the next guy.

1... I backed the rod end bearing completely out of the nutplate and looked inside. I could see 6 complete threads in there.

2... I then took the bearing and inserted it, slowly turning until it just barely catches the first thread.

3... Then I counted 6 complete rotations. This should bring the bearing to the point where it is just reaching the far end. And this position is now the furthest away from the spar the bearing can be and STILL have full engagement through the nutplate.

4... Then I counted how many turns it takes to get to the measurement called out in the plans (7/8" from the spar to the hole center). I counted 1.5 turns. Then I repeated the experiment a few more times.

Based on this, it is my opinion that backing the bearing out MORE than 1.5 turns should be avoided.

If anyone sees a flaw in this method, do speak up.