Horizontal Stabilizer Update

Over the last week I’ve spent 4.7 hours working on the front spar of the horizontal stabilizer. This required cutting a couple spar caps to shape (just like the vertical stabilizer) and drilling a bunch of holes in them, the spar, and the spar doubler. The toughest part of this though was the step where I had to fabricate a couple brackets. I’ve been putting this step off for a while because it seems like it’s kind of an important step. These brackets help position the horizontal stabilizer on the rest of the airframe so I was worried about doing a bad job and causing the HS to sit at an angle an causing the plane to not fly well or something.

I actually started to do this step several weeks ago but it didn’t start off as well as I wanted so I decided to order another piece of the aluminum angle and give it a second try. Also, the first time I tried to make them I learned that my cheap band saw really wasn’t up to the task of cutting through the 1/8 inch aluminum or maybe I just already need to replace the band saw blade. Either way, I decided that for my second attempt I would use a hack saw.

I started by marking up the part with all of the lines that I needed to cut, like this:

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Then after about an hour and a half using the hack saw to cut them out and the scotchbrite wheel to get them closer to the right dimensions they looked like this:

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I’m pretty happy with how they turned out. Like everything else so far, they’re not perfect but I’m confident they will do what they need to.

The next hard part was drilling the holes in the brackets. You drill one in each of the brackets on the larger side of the bracket. This is where the plans tell you to be very accurate because this hole positions the brackets on the HS spar. I measured, triple and quadruple checked, and then since I wanted to make sure the hole went through as perpendicular to the part as I could get it, I used my drill press to drill the holes. Then you drill two holes in the smaller side of the brackets that are used when you position the HS onto the tail cone.

Later, I got to the point where I needed to cleco the brackets onto the rest of the spar assembly and drill the other 8 holes in the brackets that will be used to attach them to the spar. The plans tell you to clamp the bottoms of the brackets to a flat surface to make sure they are perfectly aligned. The best thing I could find to use was my 4 foot level:

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Once the parts were in place with the level clamped to them I stared at them for a while. Then I had my wife come out and stare at them too. I wasn’t sure if the level was perfectly parallel to the spar not, which would be the case if I did a poor job positioning the holes in the brackets. After 20 minutes or so (ok maybe longer) I was convinced that  if they were off, then they were only off by a very small amount. If I understand the plans correctly in the later sections, then these brackets are used to make sure that the HS sits square to the rest of the airplane and so I don’t think a very small difference in their position will make a huge difference anyway. So I went ahead and drilled the rest of the holes in the brackets.

Everything is disassembled and deburred now just waiting until I have a good chance to get some priming done.

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Vertical Stabilizer Update

Several weeks ago I made the decision to replace the reinforcement plate at the top of the VS spar. Using the tip I got from Van’s, I was able to remove almost all of the rivets without any problem. Unfortunately two of the rivets were very difficult and I ended up bending the spar a little at the rivet holes before I got them out. So I just decided to replace the entire VS spar assembly.

It took me a while to get to this because I didn’t work on the plane at all for couple weeks at the end of March. I made pretty quick progress though once I started working again since this was my second time building this assembly (third time for the first few steps since the first time I replaced those parts was back in January).

I was a little concerned that holes may not line up perfectly if I replaced parts that had been final drilled while clecoed to other parts that I wasn’t replacing. I asked some other builders about it and apparently due to the precision of Van’s manufacturing process I shouldn’t have any problems.

Over the course of about 2 weeks I did all the deburring, final drilling, and priming of these parts and got started with the riveting. The riveting was going very well until one day when my wife and I were riveting the rest of the VS skeleton onto the VS spar. The middle nose rib was the first rivet we had encountered that required we use the rivet gun at an awkward angle with the offset attachment. I think I made a poor decision about which side to have the rivet gun on and this led to a very crooked rivet that I decided needed to be replaced. I didn’t trust myself to drill the rivet out without damaging more of the assembly so I decided to sacrifice the nose rib and ground the rivet head down with my Dremel tool, then pulled the rivet out from the other side.

I ordered the replacement and received it pretty quickly. I’ve already deburred, drilled, and dimpled the part. I still need to prime it but I’ve been waiting until I have other parts ready to be primed so that it’s a more efficient use of time. I’m just about ready with both of the spars of the horizontal stabilizer so I should be able to get it done soon.

Finished Rudder!

I’m actually writing this about two weeks after we finished the rudder but I set the date of the post to match when we finished the rudder.

Meggin and I spent 1.4 hours re-rolling 2 of the 3 sections of the leading edge of the rudder. I believe it was a 3/4 inch PVC pipe that worked the best for us on the smallest section of the leading edge. On the middle section we used a 1 inch pipe and then tried switching to the 3/4 inch pipe, but that ended up rolling the skin too much so after trying one side we decided to call it good where it was. We then clecoed the leading edges together, final drilled the holes (including adding two new holes on both sides of the hole I mangled with the cleco), deburred as best we could and riveted the leading edge!

The plans also say that if the skin pillows out where they were folded over the counter balance weight then you can add an additional rivet in between the screws on that section. I decided to do this because I apparently didn’t fold the skins perfectly, so it bulged more that I liked.

These two pictures were from work I did on a different day but they show some of the work I did to bend the skins over the counter weight.

The rudder isn’t perfect but now that it’s finished I’m actually pretty happy with it. It’s taken longer than it should have since I replaced so many parts but finally having a part of the plane finished is an AMAZING feeling!

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Rudder spar riveted

Once I got that shear clip in the rudder fixed I was finally able to move on to the next steps. This involved getting the rudder spar riveted to the rest of the rudder. It uses several blind rivets to join it to the shear clips and then solid rivets to join it to the skins. For the solid rivets, I started by using my pneumatic squeezer with the 4 inch no-hole yoke because it is the only one I have with the reach to get past the skin on some of the rivets. This worked pretty well but I didn’t like how slanted that yoke makes the rivets due to how much the yoke flexes so I switched to the rivet gun with the flush set and a bucking bar. I’m not very good with the rivet gun yet so I ended up putting a small dent in the skin.  That’s when I got my wife to help me. She used the gun and I held the bucking bar. This worked much better than doing the rivets by myself.

Next up was the trailing edge. We went slowly and followed the instructions in the plans and I am happy to say that it was pretty uneventful. The edge never seemed to start to curve or get wavy at all. Here’s the best photo I could get of the edge.IMG_20170318_152139

Unfortunately the leading edge didn’t go as well. The plans recommend using a 1 1/4 inch pipe to roll the leading edge so I went to Home Depot and got a 1 1/4 inch PVC pipe (I accidentally bought 1 1/2 inch pipe instead of 1 1/4). The problem with that was that the inner diameter of the PVC pipe is 1 1/4 1 1/2 inches but the outer diameter is closer to 2 inches so when I tried to roll the edge with it I was barely able to get the edge to bend at all. Luckily I had some 1 inch PVC pipe which had an outer diameter closer to 1 1/4 inches. This worked better but I didn’t do a very good job. Part of the problem was that I cut the pipe down to be a little longer than the largest section of skin that I needed to roll. This didn’t give me much room to grab the pipe to roll it, especially on the shorter sections of the skin because this meant the pipe was right up against the spar. For the last two sections I rolled, I had my wife’s help and I used a much longer section of pipe that stuck out well past the end of the rudder so I could really get the leverage on the pipe that I needed to be able to roll the edge as far as I could.

I should have gone back and done all of the other edges I tried to roll with this longer section because they weren’t rolled nearly far enough. This meant that it took a lot of effort to get the skins together to try to cleco them. I got only a couple clecos in before I realized I need to do a better job rolling the edges and tried to take them out. By the time I got one of the clecos out I had a hole that looked like this:

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Things had been going so well on the rudder for that last few days and that made this really upsetting. I was thinking I would drill out the damage and then make a plate that went behind this hole and extended to the holes on each side but another suggestion I received was to just put additional rivets next to the hole. I think I’ll do that since it should take less work than making a plate to fit behind all of the holes.

Catching up on the blog

It’s been a few weeks since I’ve added any blog entries talking about what I’ve done on the build so I’m going to get caught up in one post.

Rudder

I’ll starting off with the rudder shear clip problems I had. For the first shear clip I removed that had a couple enlarged holes, I followed Van’s recommendation and just used the next size larger blind rivet for those two holes. For the second shear clip I needed to drill out, I ordered a 90 degree drill which worked slightly better for most of the rivets. I still didn’t have the drill bit perfectly lined up with the rivet while I was drilling it out and that led to one misshapen hole. For the second rivet I drilled out with it, I was using a smaller drill bit than the rivet. This loosened the rivet up enough that the rivet was spinning with the drill bit and when I tried to pull the bit out of the rivet, it snapped off inside of the rivet. After emailing with some local builders I decided to dry to use a dremel tool to cut/grind the rivet with the drill bit out of the rudder. It was difficult to use because it was a very tight fit but the grinding bit actually caught the part of the drill bit that was stuck in the rivet and pulled it out of the rivet far enough to grab with pliers so I could pull it out. I went ahead and tried to drill the rest of the rivet out with a larger bit which actually just snapped the rivet head off so it came out really easily. Luckily the last two rivets were uneventful. The holes were so messed up at this point that I had to reorder the part. Since the holes in the stiffeners had matching mangled holes, I an idea that Van’s suggested for the first clip, and I fabricated a backing plate to go on the other side of the stiffeners. Here is what that looked like after it was all riveted together:

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Vertical Stabilizer

While I was waiting on the replacement parts for the rudder I started to rivet the rudder hinge brackets to the VS spar. One thing to be aware of is that the rivets the plans call for that go through the rudder hinges are a little short. I drilled two rivets out that I set before I realized that the reason they were squeezed way too thin wasn’t because of how I set the squeezer. So for these I used the next longer rivet size. Here are the two rivets that were too short for the hinge brackets.

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Using the squeezer worked really well until I got to a couple rivets on the hinge brackets where the squeezer just won’t fit so I had to use the rivet gun. This was going ok until I lost control of the rivet gun and it walked down the spar for a few inches. This put some small dents in the spar and really ruined my night but after chatting with Van’s they don’t think it is bad enough to be a problem and said to just smooth out the spots where the gun dug into the metal and re-prime it. Here is what it looked like:

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When I moved on to the upper rudder hinge bracket I thought I was doing pretty well until I looked at the rivet heads on the manufactured rivet side. If you look at the rivet in the picture above where the gun dug into the rivet before it stared walking down the spar you can get an idea of what I did to those rivet heads on the upper rudder hinge bracket, except they were much worse. They were bad enough that I felt I should drill them out and replace them. As with all of the other rivet drilling I’ve done this didn’t go so well. Clearly I need to practice doing it on some scrap but in this case I can also blame the rivet heads, particularly one of them, because of how badly I messed it up while riveting. This is the result of my struggles to get the rivet out:

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Due to all of the damage I did to that reinforcement plate I knew I should replace it, and also confirmed that with other builders and Van’s. Luckily Van’s pointed out to me that since I’m replacing the part directly under the manufactured heads of those rivets, that instead of drilling them out (which as we know now will probably lead to me damaging more of the spar) I should just grind off the heads of the rivets and then punch them out. I haven’t done this yet but I’m hopeful that I can do it well enough to salvage the rest of that spar assembly. Here’s a picture showing the whole spar assembly so far.

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Horizontal Stabilizer

I’ve done a lot of deburring on the first few HS parts that are worked on. The spars for the HS are around 11 feet long so they take up a lot of space in the workshop and the edges take a while to finish. I did get a little bit of final drilling done on the rear spar for the spar doubler and the elevator hinge brackets. I also riveted together what the plans call the inboard hinge bracket assembly. This was nice and easy and left me feeling pretty good about myself.

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Getting behind on the blog

It turns out that updating this blog every time I do some work just isn’t feasible for me. I’m honestly not surprised about this because I’ve never been a big fan of writing. Most of the entries written so far have been written several days later but I change the publish date to make it look like I wrote it on the day I did the work. Plus, not every building session is actually worth writing about. Since my last entry (which was about 2 weeks ago) I’ve had a couple days where I spent hours doing nothing but deburring parts and unless I come up with some magical new technique for deburring I don’t think anyone will really want to read about that. So from now on I plan to update the blog when I feel like it makes sense. Maybe I’ve had a really productive day building, or maybe I’ve completed a part, or maybe I’ve run into a problem and want to help others avoid it in the future.  I’ll do my best to not let this blog get so out of date that I can’t bring myself to get it caught up to where I’m at. You may have noticed a link at the top of the blog for my Time Log. If you really want to know how much time I spent each day, what part I worked on, and a short description of what I did, then that is the place to look. I update that every time I build so it will always be up-to-date.

Vertical stabilizer riveting pt 2

I continued rivet the VS tonight. This time I did everything with the pneumatic squeezer which produced much more consistently round shop heads. Except for the two that wanted to bend over rather then squish down nicely. I drilled those two out. I’m also not thrilled that the squeezer put a small smile around the right side of the hole when it shifted. It’s not too bad but I need to do some research about when I need to be concerned about this kind of damage. It’s not the first time I’ve done it (I know I made at least a couple on the rudder spar reinforcement plates) and I’m sure it won’t be the last time I do it.

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I also ran into what seemed like an issue when I was riveting the rudder hinge brackets to the VS assembly. I assumed I squeezed the first rivet way too far because it was way too thin so I adjusted it and tried again. This is what the first two looked like:

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Notice how thin that shop head is? Well, that is way too thin to be a structurally sound rivet. The one just to the left of it has the right thickness but the diameter of the shop head there isn’t large enough. This is when I realized that maybe the rivets the plans called for weren’t quite long enough for this spot. I have read on the VAF forums that sometimes the rivets called for in the plans are wrong, otherwise I never would have questioned the plans and may have set all of the rivets like the one on the left. Maybe that is what I was supposed to do, but I opted for drilling them out and using the next size longer rivets.  Here is the first rivet drilled out:

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When I tried a new rivet in the hole it was a little loose but I think the hole is still ok. It looks offset a little, but I think the impression around the top left of the hole is just the primer that got squished out of the way by the first rivet. Here is the second rivet drilled out after I set a new rivet in the first hole:

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This rivet came out much more nicely than the first rivet. I drilled out the manufactured head and then pushed the rest of the rivet out using a punch and a hammer, which is the way rivets are supposed to be removed. The first rivet I ended up drilling all the way out because I couldn’t get it to budge with the punch and hammer. I’m a little scared to really hit it too hard with the hammer because I don’t want to bend the parts.

The new rivets that I set in the bracket holes were much better. The shop head diameter and height were all the correct dimensions, so even if it would have been fine with the rivets the plans called for I’m much happier with these.