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.
Closeup of the Hardware
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.
- 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.
- 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.
- 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.
- 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.
- 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?
- 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. 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.
Andrew's RV-7 Build Log 