321 hours on the hobbs - Fixing the right elevator skin problem

Work sucked up all my time this past week, and I had to renew my CFI ticket by finishing an online course (that did not suck so much, but still took a lot of time). I was finally able to get back to the elevator again tonight.

After posting my latest screw up on VAF and becoming immortalized on the Aircraft - Specific link for the RV-8, and then on the front page of VAF with a "Dang it" caption from Doug Reeves, it was time to make a decision as to the solution to my dimple screw up on the elevator skin. I had several replies from differnt folks as to the best way to fix this problem. I decided to go ahead and do the following:

1. Stop-drilled the crack, which basically means that I had to drill out the hole that I had tried so hard to plug back up. As the following pics will show, now it is truly a figure 8 set of holes, but they will be filled prior to painting, and will not be visible once the paint gets applied.

This is a standard procedure to relieve stress build ups in areas where cracking occurs, and it applies to cracks in metal as well as cracks in other materials such as fiberglass, plexiglass, etc. The procedure us relatively straight forward - find the end of the crack in progress, drill a hole just slightly beyond the very end of the crack to allow the crack to migrate to, and stop it from cracking any further.

2. Flatten the dimple in the intended hole, and also in the matching hole in the stiffener, to provide as much support in the area now that I will be essentially bypassing it. I used the flat set in my rivet gun and the back rivet plate to flatten the dimples just as I did before. All it takes is a couple of light taps from the rivet gun and you are done.

3. Measure, mark, and drill 2 new holes, one on either side of the intended hole and the stop-drilled hole right next to it. These 2 new holes will provide two new contact points with 2 new rivets added to provide support for the area on the skin that was compromised with the unintended hole that was created when the skin slipped off the dimple die. I added the two new holes about half way between the intended hole and the holes on either side of that one. trying to keep the nice neat rivet line is the challenge here. We'll see how it looks after the stiffeners are back riveted onto the skin.

4. Cleco the stiffener onto the skin, and use the new holes in the skin as drill guides to finish match drilling the new holes into the stiffener

5. Remove the stiffener, debur the new holes in the skin and stiffener, and dimple them. This time I made certain that the skin did NOT slip off of the dimple die.

And here are the pics of the process. First one is after removing the existing dimples, and marking and drilling the new holes. Notice the figure 8 where I had to stop drill the botched hole in order to keep it from cracking. Click on the pic to get a larger more clear view of this. The new holes are also drilled adn visible:

And another one from the top side of the skin:

And finally a slightly blurry close up of the two holes that are now going to have to be filled. You can still see the crack that used to be along the edge of the dimple, which has now been flattened back out. UNfortunately this will be an eyesore until everything is filled and painted, since it is on the top of the elevator skin. Several folks have told me that as long as I have done this repair, I will never see a crack in this area again once everything is filled and painted. Worse case scenario is that I get to make a new elevator somewhere down the line, and maybe that is not such as bad thing either.