June 26, 2007

Started Rear Spar Assemblies - 1.25 hrs.

Today I only had about an hour to work, but I wanted to get started and get as much done as I could on the rear spar assemblies.

The first thing was to mark and trim the two inboard stiffeners for each spar, as shown in the plans. You can see the metal that needs to be removed from these parts. Van's uses these same parts for the RV-8 with no trimming required. But if you're building an RV-7 you need to mark and trim as shown. For more efficiency and less inventory requirements for the factory, it's smart to share parts on as many different aircraft as possible. I like the way Van's has done that. It's good for all of us. But it does require some work once in a while like this. No big deal. This shouldn't be a big project.

Once I had the 707D smaller stiffener marked, I decided to cleco it to the 707G fork stiffener and see if I could cut them both at once. This will make them both matched and identical and save time.

Ready to run through the band saw. Let's see if I can get away with this. It's pretty thick doubled up like this. Maybe if I go slow...

Wow! Once again, this little band saw amazes me. It cut right through both plates in no time. Nice straight cut, too. Having a new 18-tpi blade helps, I'm sure.

While they were still clecoed together, I went straight to the scotchbrite wheels and deburred and polished the edges. Beautiful! You can hardly tell it's two pieces of metal. Don't you just love having nice tools to work with?

Clecos removed, parts taken apart so I can deburr the inside edges of each piece. They are now ready for match-drilling to the spars and then priming. I'm real pleased with how these turned out.

Next, it was time to match-drill the outboard stiffener at the other end of each spar. Cleco, drill, cleco, drill... lots of holes to drill on this part. The 4 holes on the left edge (the ones with no clecos) will need to be countersunk or dimpled. In the end, I decided to dimple them, as others have done. I research a lot of this stuff online to help me make these decisions. Thanks, guys.

And now on to the center stiffeners. Lots of holes to drill here, too. There is also this funny-looking hole for the aileron pushrod to come through. It has already been drilled through the spar at the factory, but a matching hole needs to be made in the stiffener. I have marked it here on the stiffener through the spar's hole with a blue sharpie. So now it's time to un-cleco everything and figure out a way to drill this hole and shape it like the one in the spar.

But that will have to wait until tomorrow. I'm out of time for tonight.

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