New tools and light deburring

In order to avoid progressing too quickly and running out of things to do before I can buy more parts, I am intentionally slowing down my process on the project. I still plan on regular build sessions, they are probably just going to be scaled back a bit to around 3-4 hours a week or so. Of course given that I’m only a bit over a week in, that’s not saying a lot anyway…

In any case, today’s session started with putting together a new tool. Specifically, the DRDT-2 from ExperimentalAero arrived today. This is a serious device that weighs in at a whopping 60 pounds. I can’t wait to put it to work. It does come with some assembly required though. I’ll be building another worktable for the DRDT-2 that should put the dimpler right at the same height as the other tables. Combined with the platform that fits around it, it should make working with dimpling skins much easier.

After assembling the new tool, I started deburring the holes on the smaller parts of the horizontal stabilizer skeleton. After getting through a couple of the outboard hinge brackets, I discovered a couple of the holes on one of the brackets had been missed while final drilling them, so they got hooked back up to the appropriate place on the spar and drilled.

All said, I got all the outboard hinges deburred and got through about half the main ribs. Not a lot of progress, but progress nonetheless.

Session Time: 30 minutes Session: 12

They say that in the process of building the aircraft, it actually gets put together and taken apart about 3 times. Well – this will be the first… Today I got the horizontal stabilizer skeleton taken apart for deburring the spars & all of the holes that have been drilled to size. Not much to show there – its all just a pile of separate parts again now..

I also put together the cradles for the HS. There are as many different ways to setup these cradles as there are builders. I opted to simply add 2×4 blocks on each side of each cradle to provide support. This provides some flexibility in the exact positioning of the blocks. I still need to put weatherstripping back into the cradles to protect the skins from the wood, but that doesn’t take too much time.

I had also picked up a couple pieces of 1/4″ steel plate from Lowes Aircraft Supply to use as a backriveting plate. I started preparing the face of one of them to a nice smooth finish with the new DA air sander that I picked up. After a bit of smoothing out with 80 grit, there is a huge difference in the smoothness of the surface. I’ll be finishing up the surface further – aiming for a nice shiny surface when its done.

Session Time: 1 hour Session: 11

Tonight’s session was spent final drilling the horizontal stabilizer ribs to the spars. Nothing difficult, though it does take a bit of time to get to all the holes. It is a bit tricky to drill the holes through the nose ribs. I ended up opening up the flange that connects to the spar for drilling, then straightened it back to 90 degrees after the holes were drilled.

Next step is to disassemble the skeleton and debur all the freshly drilled holes and finish the edges of the spars. I plan to start working on that process tomorrow. I’m really going to have to slow down the process a bit just to avoid running out of things to do before I can get the wings. Don’t want to end up with too much downtime…

Session Time: 1 hour Session: 10

First up, make a pair of shims for the inboard ribs. The inboard ribs connect between the spars at an angle – the shims make up the difference in length compared to the rest of the ribs that are straight between the spars. The shims are fabricated from a long piece of flat aluminum. Cut to length & width with aviation snips, then grind down to final size and finish the edges.

After match drilling the shims to the forward spar, all the ribs can be cleco’d into position.

With all the ribs cleco’d between the spars, the horizontal stabilizer actually starts looking like a real airplane part. There’s still lots to be done before its finished, but its certainly a good feeling to see assemblies start to take shape!

Session Time: 1 hour Session: 9

After doing some more research and finding a more efficient fluting method, I returned to the fluting efforts for the horizontal stabilizer ribs. While most were pretty close already, they did need a little adjustment to get them nice and flat.

Basically the idea is to lay them web side down on a hard flat surface. Find the highest point that is bowing upwards and flute between the holes at that point. In order to avoid adding twist to the rib, the same spot on the opposite flange should also be fluted about the same amount. Most ribs got to flat with just one or two spots fluted in this manner.

So now I have a nice stack of pretty flat ribs. Tomorrow I can make a couple shims and put together the skeleton for the horizontal stabilizer.

Session Time: 1.5 hours Session: 8

I started this session by partially assembling the skeleton of the horizontal stabilizer to get an idea of how much fluting work the ribs were going to need for them to fit properly. Since the holes on the forward section of the main ribs were not lining up with the spar properly, it was pretty obvious that there was going to be some work required.

I found this video, Fluting ribs on RV12, on YouTube a while back about a technique for fluting ribs. The concept certainly seems sound, however, his ribs certainly appeared to have significantly more curve to them than mine do. The biggest problem I’m having right now seems to be twist in the ribs. I’ve got some ideas how to get some of that out, but I’ll probably take a couple of the ribs with me to the chapter meeting to get some more ideas. In the mean time, I’ll keep trying some things. As long as I’m gentle, it shouldn’t hurt anything.

Session time: .75 hours Session: 7

For today’s efforts, I started by finishing up the horizontal stabilizer attach bracket shaping. While they aren’t perfect, they do look pretty good. I’m planning to take them to the next EAA chapter 12 meeting to have some of the experienced builders look them over and get some feedback before doing the hole layout on them.

Next up, I added the outboard hinge brackets to the rear spar and match drilled all the holes in those to final size. These just get cleco’d in place and drilled for now.

Most of this work session was spent deburring horizontal stabilizer ribs. I’m sure I’ll be getting more efficient at this process through the project – right now, its a very slow process. Not that slow is really an issue at this point anyway. A few hours of effort in, and all the ribs for the horizontal stabilizer are nicely deburred and ready to be fluted to flat and setup in the structure.

Session time: 5 hours Session: 6

After much study over the past several months, and a bit of just setting parts together in various spots to see how they fit together, the build process has finally started. Step one in section 6 starts with assembling the forward spar of the horizontal stabilizer, then match drilling all the punched holes.

Next up, fabricate some attach angles. These two parts are supplied as a piece of angle that has to be cut down to size. These parts do have a bit of a complex shape to them, so it took some thinking to come up with a plan for manufacturing them. I ended up cutting them to rough length on my mitre saw to get the angle right. The width of both pieces is being cut with the dremel to rough size. Once these are cut close to their final size, the remainder of the work will be done on the grinder, slowly creeping up to the final sizes. I must admit that reading other builders accounts of this process had left me a little bit nervous about it, but so far they have not been any real issue.

While waiting for one of the attach angles to cool from a round at the grinder, and for the dremel’s battery to charge, I went ahead and assembled and match drilled the rear spar.

Later, I continued working on the attach brackets. I’ve got one of the pretty well finished on the shaping, though I did end up making it about 1/16″ wide. It should be fine though. There’s a bit of room available, as long as I do the hole layout properly anyway.

Its shiny and nice!

I still have a bit of work to do on the other bracket. It’s about 1/8″ too wide right now – a bit too much too big. Better too big than too small though.

Other than just being the first work done on actual airplane parts, there isn’t anything *too* exciting. Nothing that really looks like airplane parts yet – unless you squint just right….

Session time: 2.5 hours Session: 5

After getting a small window A/C unit from my parents this afternoon, I got busy working on the toolbox. Besides being great practice, this gives me something small enough to pack around and show off. I started by bucking the last 4 rivets on each end of the box that I couldn’t reach with the squeezer. Feeling good about the rivet bucking, I decided to just buck the rivets that hold the front stiffener on as well:

You might be wondering what’s going on in the last two pictures….. Well… so much for those rivet bucking skills.. Still, it wouldn’t be a practice project without a couple mistakes on it. Unfortunately, the rivet gun got away and happily went skipping down the side of the box. Ouch! Oh well – gives the toolbox character. Its mine!

Next up, dimple the hinges and attachment points:

Doh! There aren’t supposed to be two holes there! Oh well – better an itchy trigger finger in practice than on the real thing. That pneumatic squeezer is *quick*. Fortunately the hinge covers most of that mistake.

With the hinges riveted on (I squeezed those ones), the rest of the project is down to finishing touches. First the latch is added. I’m not entirely happy with how the rivets set on the lower part of the latch. I’ll have to ask around for some ideas on how to tackle rivets like those in the future. Finally the handle is bent into shape and attached to the lid.

All in all, I’m pretty happy with how it turned out. Now it just needs to be polished up to a nice shine, and I’ll have a pretty nice toolbox to travel with.

Session time: 3.5 hours
Project total time: 7.5 hours

In order to brush up on the sheet metal skills before working on actual airplane parts, I bought the toolbox practice kit. Besides just being good practice, the end result will be a nice looking small toolbox that will probably get some basic maintenance tools put in it and put in the back of the plane for most trips.

Start by deburring edges and assembling the ends:

Match drill, dimple, and rivet with flush rivets:

I wasn’t able to reach the middle rivets with the squeezer, so those will need to be bucked. Rivet guns are *very* noisy though, so it was already later in the evening than particularly acceptable for that. I don’t want to annoy the neighbors too much..

Next up is fitting the hinge for the top. First it gets marked and cut to length. Then the hinge is positioned on the box. Finally the hinge is positioned on the lid.

With the hinge assembled with cleco’s, the toolbox starts to look like an actual toolbox.

Session time: ~4 hours (not logging towards aircraft totals)