Over the course of the week and weekend, I was able to debur all the Elevator parts. There are a lot of them! I also started dimpling things.. up until I broke my male 3/32″ dimple die. UGH! I use Cleavland’s tight fit dimple fixture, and a rivet set to hold the die in my rivet gun. I did’t think I was off center or anything, but somehow the male pilot of the dimple die broke off. So I’ve ordered a couple of replacements. I’ve asked a local friend if he has one I can borrow, seeing I’m mostly stuck needing to finish up all the dimpling prior to priming and riveting the structure together.
While deburring one of the skins, I managed to push my cordless drill off the bench with my 2.5mm Ezburr bit in it. Needless to say, the Ezburr bit didn’t fair well.😦
So today, I dimpled any 1/8″ holes and did all the countersinking needed to some holes on the top of the rear spars and the trailing edge wedges. I also prepped the skins for the foam ribs used on the trailing edges by marking their positions and snuffing up the metal with sandpaper for better adhesion.
Below is a time lapse video of me dimpling one of the four elevator skins.
I finally was home for a weekend and finished up the work on the VS repairs. I haven’t been home on a weekend for the last month. Progress has really slowed over this crazy summer.
Once I got the parts I ordered, I deburred, final drilled, and dimpled them as required. I also upsized the flange holes of the lower 2 ribs that attach to the spars. I buggered those holes a little when drilling the rivets out, so I upsized them with a #21 drill to take an AD5 rivet.
I feel so much better about how this came out.
I’ve also finished up final drilling of the elevator skins, dimpled the cover plates, stiffener, and nutplates, and disassembled the entire assembly. Now it’s time to have fun deburring everything.
After my tech counselor meeting, I’ve managed to fix the rivets along the front spar of the rudder. While not all of them were bad, rather then go one-by-one, I just decided to drill all of them out along both sides of the front spar. Some of them were hard to judge with the leading edge already rolled, so I just decided to do all (approx 110) of them. I also fixed the 4 over-driven rivets on the VS as well.
On my Vertical Stabilizer Assembly and a Mistake post, I outlined a mistake that I had made in the VS when I bent the nose rib flange by trying to pound a drilled out rivet (prior to perfecting my rivet removal technique). Vans had said it was okay to bend back and build on, which I did. I never did quite bend it back good enough to not leave a small gap between the flange and the skin. This made riveting difficult, and I was not too happy with how it had come out. This is one topic that I had discussed with the tech counselor, and we talked about drilling it out and putting a Cherry Max rivet in there in the hopes that it would capture the flange while pulling and close the gap. After attempting that, I’m still not happy with the results.
There was one other picture that I had taken of the bend in the flange and when I looked at it at the time, I swore was just the primer that had come off at the bend and not a crack, but my gut was telling me between that picture and being unhappy with this nose rib riveting, I should open up the VS and fix it the right way.
So I looked at replacement costs for the nose rib and probably a new skin (approx. $100) so a no brainer. I probably don’t really need a new skin, but I also have a small outward dent from the corner of the bucking bar in one spot that likely only I’ll ever see, this would be a good opportunity to fix that small blemish. So away I went drilling out the skin of the already finished VS! Yikes!
I’ve only got one side of the skin off at this point, and I’m glad I opened her up! I wiped off the primer with Acetone and I’m now 100% sure that there is a crack in my nose rib where it bent.
Moral of the story is to trust your instinct. When something doesn’t seem right, go make it right. I know I’ll sleep better at night knowing that this is fixed and solid. The minor inconvenience now is nothing in comparison to seeing a fully developed crack later down the line.
Now it’s off to vacation for a couple of weeks. I’ll order the parts when I return and keep making progress on the elevators in the meantime.
Tonight my local EAA Tech Counselor stopped by for an initial visit. Overall it went well.
We reviewed the VS, which he said was good. There were only 3 rivets he identified that were too over driven, 2 of which really look like they weren’t the correct size, even though I’m pretty sure I used what was called for in the plans. He had said that sometimes happens and to use the rivet gauge when in doubt. Luckily all of these rivets are in easy to access locations so the fix should take 10 minutes. No other qualms with the VS.
We then reviewed the rudder. There was one AN470 rivet on the counter balance rib that had a smiley that he said was not really acceptable. So I will be replacing that. The bigger issue was that a large portion of rivets along the front spar were clinched over too much. I remember using the zero hole yolk in my squeezer for these seeing the leading edges weren’t rolled yet. I needed the extra depth in order to squeeze these rivets. Problem is, the zero hole yolk has a little more play in it, and it was my first time using it. The result was marginal at best. He admitted to not really liking the zero hole yolk himself as it has too much play, and would rather just drive the rivets. That is probably what I should have done… He said if it were him, he’d probably replace them otherwise several years down the road, I’ll end up having some smoking rivets. Oh well… live and learn. This is the whole reason for having a more experienced eye looking over my work from time to time. So I will be drilling out the rolled leading edge pop rivets and redoing several of the rivets along the forward spar. A few hours spent correcting this will give me piece of mind that I will end up with an airworthy airplane.
We then looked over the horizontal stabilizer, which is the piece I just finished. He didn’t find anything wrong with it!!! He commented that it was a very good looking piece, and that my riveting skills have certainly improved! Certainly a good thing to hear.
We spent a little time looking at the elevators in progress and talking about deburring. He commented that I did a very nice job on the tab bends on the skins.
The perfectionist in me feels a bit beat up, but I suppose all in all it’s not too bad, and everything identified is easily fixed. A good learning experience (as this whole building process will be) and some things to look out for in the future. I’ll take a little time correcting these things and then keep moving forward.