Elevator - Rod end bearing adjustment

Fearless · #1 11-30-2006, 05:47 AM

When I tried to pre-install my left elevator to the horizontal stabilizer on my 9A last night I had the leading edge of the elevator scrapping the trailing edge of the horizontal stabilizer spar on the outboard side toward the counterbalance. The inboard side seemed to have plenty of clearance. I set the bearings at the recommended 13/16 distance. The plans say you can have a maximum of 7/8 distance. I'm guessing that the distance needs to be the same for both bearings. Is that correct? If they weren't I would think the only way you would notice is the gap between the counterbalance rib to the horizontal stabilizer. I tried searching the site for answers but didn't really find what I was looking for. Need feedback please.

Thanks,

pierre smith · #2 11-30-2006, 06:49 AM

Hi Mike,
Just back out the bearings to get more clearance. In order to not have any binding between the three bearings, I pulled a string through them (from the tip to the center bearing) and got them aligned with each other.
Regards,

TerryWighs · #3 11-30-2006, 08:51 AM

HI Mike,
It may be possible to use a laser light to pass through the center of the rod end bearings to get optimal alignment???

alpinelakespilot2000 · #4 11-30-2006, 09:54 AM

Unlike on the rudder, there are only two rod end bearings on the elevators, so alignment issues requiring a straight line or laser are basically non-existent. That said, start from Van's measurements and adjust as necessary (within reason) to get the counterbalance arm parallel to the HS.

Also, make sure your counterbalance arm is perfectly perpendicular to the rest of the elevator. When I originally riveted mine it was not perfect and caused the forward part of one counterbalance to rub the HS. Had to drill out a few rivets to get everything square and then re-riveted. Solved the problem and allowed the rod-end bearings to be adjusted pretty much equally.

Hope this helps. Good luck.

JVolkober · #5 11-30-2006, 11:57 AM

I just went thought the same exercise. The leading edge of both elevators when fully deflected rubbed against the rear spar of the HS with the rod barrings set at maximum length. I also had a problem with the right counter weight arm not sitting parallel to the edge of the HS.

The leading edge rubbed against the shop head of one solid rivet and the head of one pop rivet. The solid rivet was at the end of the HS so I compressed it slightly with a squeezer. I filed the pop rivet head to allow additional clearance. To fix the rubbing against the spar, using only hand pressure a slightly reshaped the leading edge of the elevator. The problem was a very slight bulge in the curve of the top of the leading edge, imperceptible to the eye but enough to cause the rubbing

Regarding the lack of a parallel gap between the HS and the right counter weight, I tried using differential lengths for the rod bearings. That did not work because the gap between the leading edge of the elevator and the HS was very noticeably out of alignment as were the left and right elevator horns. So I have decided to live with the slight lack of parallel in the gap between the counter weight arm and the HS. I considered the possibility of removing rivets and fixing it. However, it seems like it would require removing all the rivets attaching the skin to the rib. That seemed like a little too much for me, even after having remove several hundred rivets during the HS assembly - another story for another time.

alpinelakespilot2000 · #6 11-30-2006, 12:06 PM

Quote:

Originally Posted by JVolkober

Regarding the lack of a parallel gap between the HS and the right counter weight, I tried using differential lengths for the rod bearings. That did not work because the gap between the leading edge of the elevator and the HS was very noticeably out of alignment as were the left and right elevator horns. So I have decided to live with the slight lack of parallel in the gap between the counter weight arm and the HS. I considered the possibility of removing rivets and fixing it. However, it seems like it would require removing all the rivets attaching the skin to the rib. That seemed like a little too much for me, even after having remove several hundred rivets during the HS assembly - another story for another time.

Don't give up yet. The only rivets you need to drill out are the 6 rivets for the overlap of the elevator skin with the counterbalance skin. The two inboard ones will require the use of pulled rivets since you won't be able to buck them, but Van's OK'd to me the use of them. (Go to an airshow and you'll see a lot of pulled rivets there.) It took me about 30 minutes tops to fix it, but I had stressed about it ever since I finished the elevator almost two years ago. I just got around to trying Van's recommended fix when I fit the emp. to the fuse a few weeks ago. After I was done I wondered why I had worried about it for 2 years. Good luck.

rlo1 · #7 11-30-2006, 02:52 PM

"In order to not have any binding between the three bearings, I pulled a string through them (from the tip to the center bearing) and got them aligned with each other."

I wish I had though of that a while back. Would have saved me several hours. Nice tip Pierre!

-Ron

Fearless · #8 12-01-2006, 06:02 AM

When I pulled the elevator back off I could see scratching on it where contact is being made. I'll adjust the rod end bearing the last 1/16 to get the 7/8 distance and recheck the clearance. I filed down a little of the middle rivets on the rear spar on the horizontal stabilizer to get some extra clearance. Hopefully this will do it.

I should get my bearing adjustment tool from Avery today so it should make it much better dealing with the rod end bearings themselves. Most people probably already know this about Avery but they go way beyond the term - customer service. I've never been keep so informed about the status of a purchase before.

Thanks for the replies. You guys(and gals) are the best.