Elevator Updates

I’ve put about 50 hours of work in since my last post so I figured it was time to update the blog. Work has slowed down a bit recently because Meggin and I adopted a puppy and we’ve been giving her tons of attention, but I’m starting to get back into a good routine of working on the plane.

Since my last post, I have back riveted the elevator stiffeners to the elevator skins

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While doing the very last rivet on the very last stiffener, I let the rivet set slip off the rivet and dent the skin a tiny bit. Of course, the dent is on the top skin of the elevator instead of the bottom where no one will see it. It’s not too bad though.

I riveted the stiffener halves together to join the elevator skins. This was a little tough since there isn’t a lot of space between the skins to get your hands into but otherwise it was uneventful.

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Then I riveted the spar to the stiffeners and the skins.

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Riveting the tip ribs to the elevators requires setting some rivets in a really tight spot. I checked other builder blogs and no one else seemed to have any trouble with these rivets but I had a terrible time with them. I could not prevent them from bending over. I drilled out at least 3 rivets before I found out from Van’s that blind rivets were an acceptable replacement for the solid rivets here. Unfortunately though, I did a terrible job of drilling out the first rivet I set and enlarged the hole quite a bit. I ended up having to use a larger rivet for this hole, and because the larger hole no longer had the correct distance from the edge of the flange it is located on, I had to build doubler plates for both sides of the hole and add a couple extra rivets to the flange. I don’t think the hole looks too bad in this picture but in the horizontal direction it is large enough for a 5/32″ rivet even though it is supposed to use a 4/32″.

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Then I was ready to give the trim tabs another attempt. This time I used Scotch brand double sided tape and cut new blocks for clamping the skins down. I found that by setting my table saw to about a 10.5 degree cut, I was able to cut out a wedge that matched the angle of the trim tab almost perfectly. Everything went well at first. I bent the outboard tabs of the trim tabs without any trouble. However, when I started to bend the inboard ends the wedges were sliding as I clamped them down. My best guess is that the leftover glue from the tape I had been applying, removing, and reapplying every time I moved blocks was preventing the new tape from holding properly. So, the bottom block slid out of the trim tab and the upper block slid down which resulted in another dent near the trailing edge of the trim tab skin. Luckily I planned ahead for something like this to happen and put the top of the skin against the table so the dent is on the bottom of the trim tab. I don’t want order more trim tab skins unless I really have to so I’m going to build on for now. When I did the second skin I added another clamp to prevent the inner block from sliding out, but the upper block still slid down so I ended up with a less severe dent in the second trim tab. You can see the smaller C-clamp that I added in the second picture below.

That brings me up to where I’m at now. Last night I added the bend to the bottom flange of the trim tab skin and reassembled the trim tabs so that they are ready to be final drilled next time I work on them. I’m hoping that over the weekend I’ll be able to get the foam ribs and trailing edge wedge glued into the trim tabs and elevators with Proseal.

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Elevator riveting pt 2

I spent about an hour and a half working on the elevators tonight. I got the nutplates that are used to hold the elevators onto the HS riveted to the front spars. I had to drill out a couple rivets in one of these because the shop head of one rivet cracked and the other I didn’t have the pneumatic squeezer lined up properly so it bent the rivet over.

I’m pretty sure the next step where I rivet the root ribs onto the front spars might require the rivet gun instead of the squeezer, so I decided to move onto another step that would use the squeezer. I dimpled all of the nutplates that go onto the trim access reinforcement plates and then riveted them to the plates. Dimpling these nutplates requires that the female dimple die be ground down a little on one side otherwise it will run into the dimple that the screw goes into. Luckily I already have some dies that have been ground down that came with the tools I’m borrowing from another builder.

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Ruined trim tabs and first elevator rivets

Well today I tried to bend the tabs on the ends of the trim tabs and things didn’t go well. On my first attempt the wooden blocks I used dented the skin pretty badly on one side and the tape didn’t want to come off very cleanly. Rubbing alcohol and lacquer thinner didn’t work to remove the tape residue, maybe actual adhesive remover would work but I didn’t have any to try. I went ahead and bent the tabs on the other side just to get a little practice before moving on to the other skin.

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For the second skin I tried using a different tape. I saw on VAF somewhere that someone had good results with carpet tape so I decided to give that a try. The stuff I tried wasn’t going to work because when I clamped everything down the tape squished a little and let things slide around. Unfortunately the tape stuck so well that by the time I managed to get the wood blocks off of it, I bent up the skin really badly. So I have two new trim tab skins on the way.

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After that, I still wanted to make some progress today so I started riveting the other parts of the elevator together. With some help from Meggin, I got the counterbalance rib assemblies together and then riveted the reinforcement plates to the front spars.

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Finished Trim Tab Bends

I finished the bends in the trailing edges of the trim tab skins last night. I followed the recommendation in the plans and built a bending brake out of two pieces of 2″x8″ and a couple door hinges. The only issue I had was that the middle of the brake wanted to bend the skins farther than the ends of the brake. I dealt with this by shifting the skins around in the brake to make sure that the entire length of the skin eventually had a chance to get bent by the middle of the brake. I think they turned out fairly well and according to the instruction manual, the trailing edges can be cleaned up later if they need to be.

Also, I didn’t mention this in my last post about priming all of the elevator parts, but I also primed these skins as well. I figured they would be a lot easier to prime before finishing the bend, and seeing how close the sides come together after finishing the bend, I’m definitely glad they are already primed.

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Elevators primed and ready for assembly

Over the last couple months I’ve been working hard on the elevators. At this point all of the elevator parts and primed and ready for final assembly. We had really nice weather over the weekend so it was a good time to prime but ever since then we’ve had snow and below freezing temperatures, so I’m giving the parts some extra time to cure before I start riveting them together.

I had a couple minor issues when getting the elevator parts assembled and drilled. First, the holes on the counter balance ribs and counter balance skins didn’t really want to line up well. It took some work wiggling the clecos but they eventually got where they needed to be. Then final drilling made everything fit a lost better.

Second was when I was attaching the counter balance assemblies to the rest of the elevators. There are two holes that match up with holes in the spar, that were not lining up either. These holes were about halfway out of alignment and forcing them with clecos wasn’t an option. Van’s suggestion was to match drill the holes, and then since those holes turn out oval shaped, to make a doubler for the flange and add two more holes. Here you can see just how badly out of alignment the two holes were, and then the double with four holes that I added to it on the other side when I drilled the 4 holes:

Everything else went pretty well. The skins have tabs that have to be bent on them to close off the inside of the elevators. I was nervous about messing up this part but they turned out pretty well. You clamp the skin between two pieces of wood where you want the bend to be, and then start the bend with your hands and finish it off with the rivet gun set to a low pressure. I still had to finish off the bend with the rivet gun in this picture, but this is what my setup looked like:

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Got to use my unibit for the first time to enlarge a hole in each of the front spars.

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Prepping and priming everything took about 6 hours. Luckily I had Meggin to help me otherwise it would have taken a lot longer

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And just a couple other pictures showing the elevators cleco’d together:

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I tried to use the recommended setup from Van’s for counter sinking the trailing edge wedges using a drill press, hoping it would turn out better than my rudder wedge, but I still had some problems with one of the wedges. The bit still chattered and made quite a few countersinks that are way too deep, so I ordered a replacement and will try again soon.

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Progress Update – HS & VS finished, working on elevators

I have been meaning to do a couple posts to get caught up on my progress but I just keep getting further and further behind on it, so I’m just going to do one post covering everything. The quick summary is that I’m now finished with the horizontal stabilizer, vertical stabilizer, and have started the elevators.

The first issue I ran into with the horizontal stabilizer was when I riveted the attachment brackets onto the front spar. I gave some of the rivets “smiley’s” while setting them and instead of stopping and figuring out what I was doing wrong I just kept going. So in the end about half of the rivets in each bracket had (what I would consider) fairly bad smiley’s. They looked like this:

 

I got some opinions from Van’s and a couple local builders and 2/3 said I should replace them, so I did. Because these rivets go through about half an inch of parts, I followed a tip I found on VAF that suggested drilling almost all the way through them using a drill bit for the next size smaller rivet. Then insert a punch into that hole in the rivet and punch them out. When I did this, I wasn’t perfectly aligned with the drill so some of the holes got enlarged, and misshapen slightly. Since these brackets are pretty important, I had a tech counselor come take a look at the holes to see if I should replace the parts but he thought they didn’t look too bad. I also emailed Van’s about it a bunch and the person I spoke to also felt that they should be ok. So I put some new rivets in them and once I get the plane flying, I’ll be sure to keep a close eye on them to make sure they are holding up well.

We didn’t have any really big issues with the rest of the HS. Meggin helped me with all of the flush rivets in the skin because I don’t trust myself to use the flush set on the rivet gun and the bucking bar at the same time without putting a dent in the skin. I did have to drill out quite a few rivets because working in the tight space of the inside of the HS cause me to slip with the bucking bar and damage some rivets. Two of the gave me so much trouble that I ended up having to replace them with oops rivets. Here are some pictures from the rest of the HS build:

 

Next, we moved on to riveting the skin onto the vertical stabilizer. I hadn’t done it yet because I was considering running wires through the VS to connect a camera that I would install in the tip of the VS. I couldn’t decide how I wanted to do that so I had been holding off on finished the VS. I finally gave up on that idea and decided that if I want a camera there, I can temporarily attach a camera for the flights I actually want to record.

Some of the rivets on the skin of the VS were hard to do simply because I had to reach my arm all the way into the VS to get to the middle ribs and that made it difficult to see what I was doing. Another section has you peeling part of the skin up so that you can reach the rivets in the front spar. I really didn’t like this part because I couldn’t see what I was doing with the bucking bar at all. I know some people mange to do all of this work by themselves, but I’m glad I had Meggin to help me. Even with help though I managed to slip off of a rivet on the front spar and added a small bucking bar shaped dent to the skin. It’s not too bad so I’m hoping that after it’s painted it won’t even be noticeable at all.

 

So one weekend we got the HS finished and the next weekend we finished the VS. It was a very satisfying week 🙂

Now, I’m working on the elevators. Luckily I already had most of the parts deburred, but it still took me several hours to debur the spars and skins. So far, I have bent the close out tabs on the skins, I have drilled the trim cable routing holes, which was my first time using a unibit, and I have begun clecoing everything together.

 

 

Started riveting horizontal stabilizer

Last night I got started riveting the first parts of the horizontal stabilizer together. I used the pneumatic squeezer for most of it but had to use the rivet gun for some of the rivets. The rivets I did with the gun are not perfect, but I think they turned out fairly good. At the end of the night I had an assembly that looked like this:

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In the weeks before this I spent a lot of time countersinking all of the holes in the spars and stringers and then priming everything. The single flute cutter I ordered worked really well right up until it broke so I switched back to the 3-flute cutter I had been using. A common issue people have with the 3-flute cutter is that it chatters in the hole and creates a bunch of small ridges in the countersink. I found that using my electric drill on the slow speed setting seemed to prevent this from happening, and also helped me avoid having the bit cut sideways through the hole.

I broke up the priming into two sessions. I primed the skins during the first session and everything else on second.  The second session turned out do be my longest priming session to date. Even with Meggin’s help prepping the parts for primer it was close to a 6 hour session. I wasn’t sure we removed all of the residue from etching the parts so we decided to go back and clean everything again so that added a lot of time, plus I was using a new spray gun that I had to learn how to use first.