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SB 14-02-05 Elevator Spar Cracks

RV8Squaz

Well Known Member
Hello,

I’m getting ready to perform the service bulletin that repairs the cracks in the elevator spar. I have cracks emanating from the upper and lower rivets that hold the nut plates for the outboard rod end on each elevator.

I’m at the point where I need to drill out the rivets. Normally, when drilling out a rivet, one drills enough to snap off the head and then punch out the rivet. I fear using this procedure to drill out these particular rivets will result in bending the nut plate ear out of the way and leaving the shop head buried in the nut plate ear. I think even normal drilling pressure could mess things up since the only thing holding the nut plate in place is the rivet in the opposite ear.

I could figure out a way to to keep some pressure on the nut plate against the interior doubler of the spar while I drill. I could do this by threading in the rod end bearing with the jam nut back in instead of using the nut plate holding tool. Once the rivets are drilled out and the nut plate held with Clecos, I could then use the nut plate holding tool and proceed with the rest of the SB.

So what have you done? Did you run into any problems drilling out those rivets? Did you drill, snap off the head, and punch out the shank or did you simply drill all the way through?

Thank you!

Jerry
 

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I have and understand those instructions. The problem will surface when actually trying to punch or drill out the shank. The holding tool is there only to keep the nut plate from falling into the elevator.

Thanks.
 
Drilling Rivets

Jerry,
Don't punch out the rivets. Drill then all the way thru and start with a under size drill and work your way up. That should keep the nut plate ears straight. Don't use a lot of pressure, let the drill work for you.
 
Thank you Kurt! That’s exactly what I was thinking about doing. Thank you for the confirmation. Have you had to do SB?
 
Kurt,

Your suggestion was spot on. I drilled and snapped off the heads in the normal fashion. That left a little divot in the rivet shank from the point of the drill bit. I drilled into the divot using a #44 bit. It went right through the middle of the shank. I followed that up with a #30 bit and drilled out the remainder of the rivet effortlessly. I did use the rod end with the jam nut to retain some pressure against the doubler. I used the nut plate holding tool later. Easy peasy. Thanks!
 
Jerry, regarding the cracks, do you have an idea what may have caused them? Were the jam nuts loose?
 
Jerry, regarding the cracks, do you have an idea what may have caused them? Were the jam nuts loose?

No, I don't. The SB applies to All RV-3, 4, 6/6A, 7/7A, 8/8A Flying aircraft. I believe cracks have occurred on aircraft flown in all kinds of conditions. This is a known issue amongst several models that has occurred enough to warrant an SB to be published by Van’s.

I have heard that it may have something to do with a misalignment of the hinge line. My hinge line and rod end bearings are in perfect alignment. With all of the hinge bolts tightened correctly, the elevators swing perfectly freely. My airplane hasn't been flown outside of the design envelope. And I’m proud to say, I’ve never had any loose jam nuts anywhere. Vic Syracuse would be impressed!:)

Many aluminum airplanes develop fatigue cracks. It's really not that uncommon. How soon those cracks develop will reveal if the design was sufficient or not.
Is 14 years and 1800 hours soon? No one knows.
 
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