The elevators are done with the exception of the trim tabs… Well the first iteration of the trim tabs anyways. The main mistake I made on the trim tabs was bending the close-out tabs on the end too close to the reliefs in the skins. I misread the directions and thought I was supposed to put the supporting wooden blocks 1/32″ to the inside, when really it was in the opposite direction. The end result is some bulging as you approach the ends of the tabs because the tabs are too long. Not real terrible, but I’m just not happy with how they came out. So parts are on order to build new ones, which won’t take more than a few hours to complete.
I bought a new compressor to give me some more capacity and be a little quieter seeing it’s in the garage with me. I decided to get a 2 stage, 60 gallon model from Harbor Freight. It refills very quickly now and is much better when running the air drill or spraying primer.
Since the last post, I’ve made a lot of progress on the Elevators. Below are some pics documenting the process.
I had a nice day to move the priming outside for this round. I used an old grill top from my pig roaster that I never use to provide a better backdrop for the spraying. Previously, smaller parts would really move around, flip over, etc… I figured it was because I was spraying against a hard surface and not something that the air from the spray gun could blast through. Happy with the results. The setup is shown below with all of the parts laid out (minus the skins)
Various pictures of initial riveting of the spar and spar stiffeners, trim access stiffener and nutplates, stiffeners back-riveted to the skins, and pop riveting the ribs in some tight quarters.
A video of me using the special RV-10 Emp bucking bar that I bought with my toolkit to rivet the rear spars
Most riveting done.
My rudder trailing edge came out okay, but I wasn’t 100% happy with how the joining of the skins came out using the VHB tape. Seeing the foam ribs are attached to the skins with Proseal, I decided I would also use the proseal for the trailing edge as well to see how it goes and compares with the VHB.
I also decided to use the steel bars I have and match drill them to the trailing edge holes so the clecos end up holding everything tight to a straight bar.
I then spent some time riveting the trim covers and trim attachment brackets together, along with marking and trimming the counterbalance weights.
Now to wait a few days for the Proseal to cure. In the meantime I’ll start working on the trim tabs.
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.