Practice Kit – Finished

October 4, 2009

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Sunday morning, I managed to finish off the practice kit. Here are the pictures.

Here are the skins riveted to the spar. Notice how I didn't make the jig to hold it to the table.

Here are the skins riveted to the spar. Notice how I didn't make the jig to hold it to the table.

Another shot of the skins riveted to the spar.

Another shot of the skins riveted to the spar.

After the skins were riveted to the ribs and the trailing edge wedge, I rolled the leading edge and clecloed it together. I haven't edge formed the top skin yet, hence the ripples.

After the skins were riveted to the ribs and the trailing edge wedge, I rolled the leading edge and clecloed it together. I haven't edge formed the top skin yet, hence the ripples.

The finished product.

The finished product.

Overall, I am happy with the results. I don’t think they are airplane worthy (I don’t know if I will ever be happy with the final product), but I feel like I am ready to start on the real kit. All of the riveting came out nice, but some of the other aspects (dimpling, countersinking, edge rolling) are still not up to par.

Biggest lesson so far:

1) Go slow, take your time, read the plans, and be careful.
2) The skins don’t look too bad, but I have a feeling there will be too many scratches to polish the final airplane. I’m planning on paint anyway, so I should be okay.
3) Other things, I want to acquire some of the tank dimple dies for the understructure. Some of the skin to rib seams didn’t sit as nicely as I wanted, and I think the slightly deeper dimples in the ribs will accept the dimple in the skin better.
4) Buy a bigger backriveting plate. I just have a 1 x1/2 x 36 inch steel stock. I had to be really careful to keep the rivets lined up. With a wider plate, I wouldn’t’ have had to move the skin around, which caused…
5) …scratches in the skin. Next time I removed the vinyl from the skin, I am going to immediately replace it with painters tape. All of the scratches on the skin are where I removed the vinyl. This can be prevented.
6) Priming. Using the self-etching primer is so easy, I think I may do all of the interior skin next time ( I only primed the rivet lines, where two pieces of metal would meet this time).
7) I need a no-hole yoke for the rivets near the rear of the trailing edge. I managed with a thin bucking bar, but I didn’t like the results. A no-hole would make this a non-issue.

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Practice Kit – Riveting

October 2, 2009

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I started riveting today. I got the skeleton riveted together and back-riveted then stiffeners to the skins.

Skeleton riveted together.
Skeleton riveted together.
Skins back-riveted. Nice, huh?
Skins back-riveted. Nice, huh?

I’ll try to finish up tonight, but I need to figure out a way to dimple the ribs near the trailing edges. I should probably follow the directions and fabricate the special dimpling tool described in the plans. Off to the hardware store for some steel…

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Practice Kit – Stiffeners and Skins

September 30, 2009

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I started on the real practice kit today. First, you have to make the stiffeners. Easy as pie, except the stock I got in my kit was cut short by about 1/2″ in each case. I got two shorter sections, the kit shows it comes as one long piece. Maybe George gave me some extra that was laying around. No biggie, but that’s why in the pictures below the stiffeners are different lengths. Then I edge prepped the stiffeners, ribs, spar, and skins. I also practiced using the soldering iron some more, with pretty decent results. Here’s a shot of the stiffeners and skins ready to match-drill.

Skins and stiffeners ready for match drilling.

Skins and stiffeners ready for match-drilling.

And the stiffeners match-drilled to the skins…

Match-drilled and cleco'ed.

Match-drilled and cleco'ed.

After this, I assembled the skeleton, matchrilled both skins to the ribs, spar, and trailing edge wedge, then disassembled everything. It got late, so I stopped after getting all the holes deburred. Here’s a shot of the skeleton clamped together, ready for drilling.

Skeleton Clamped

Skeleton Clamped

Next step is to figure out a priming process and test it out before dimpling and riveting.

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Started on the Practice Kit

September 28, 2009

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Today, I started on the practice kit. The directions point back to (and the kit actually includes) sections 3 and 5 of the construction manual. I threw my extra copies away, I’m going to just keep the ones from the Preview Plans I have.

The kit tells you to make some useful tools before starting. I found 3: A wooden hand seamer, a stand for your practice kit (basically a place to clamp the front spar so the skins stand up vertically) and an assembly with an 11 inch long piece of angle riveted (with various rivets) to two more pieces of 2.25″ x 11″ aluminum sheet. I’m not sure if this is a useful tool or just something to rivet before starting the pretend control surface. Hmm… I’ll make it nonetheless for the practice. I’m going to pass on the hand seamer, but get started on the other two.

Interesting note, the directions tell you that if you don’t have dents, scratches, and mistakes on your practice kit, you aren’t doing it right. Apparently, they want me to get out all of the mistakes now before I start on the real airplane. Right…

Here’s a picture of everything that comes in the kit.

Everything that comes in the kit.

Everything that comes in the kit.

Closeup of the Hardware

Closeup of the Hardware

Closeup of the skins.

Closeup of the skins.

I didn’t get very far on the practice kit. I made it through step one, which is to drill the weird angle assembly in 24 places for the appropriate flush and blind rivets of various sizes. Even the practice kit is going to be slow going. I did learn a ton, though.

  1. Everything is so tiny. I’ve been staring at picture on all the build sites, thinking things were bigger. The -3-3 rivets are TINY! The skins are a lot thinner than I thought they would be.
  2. Don’t take the blue off the skins if you don’t want to scratch the skins. I thought my workbench was clean, but after deburring one of the small sheets, there were small pieces of aluminum everywhere. I slid one of the sheets on the table and scratched the hell out of it.
  3. My cheap clamps are nice, but not perfect. I’ll need to get some higher quality ones. Also, I need to use the duct tape on the clamp face trick. They scratched the hell out of the sheet, too.
  4. I had to measure, mark, and drill the holes. No big deal, but I just noted that they really have you jump right in. I drilled into a spare piece of MDF I had laying around, but I didn’t drill far enough, so the clecos don’t have a fantastic grip. Oh well.
  5. I played around with pressure on the bit while drilling. I learned as a kid that when you have the spiral piece of metal coming off in one piece as you drill, that is the right pressure (which wasn’t that much more than the air drill itself). Anyone have any other advice?
  6. I learned that building is not going to be a piece of cake, but is going to be a lot of fun. That’s kind of a fluffy statement, but it’s true.

Here’s the picture of what I got done last night.

Step one. Drill appropriate holes.

Step one. Drill appropriate holes. Don't make fun of my erroneous markings. The instructions said I have to make mistakes on this practice kit, and not the real airplane, so I made sure there were some errors.

Also, I had to cleco the skin to the end ribs. I don’t know why, but I wanted to do it. I promise not to skip steps in the future.

Top skin cleco'd to the end ribs.

Top skin cleco'd to the end ribs.

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