Stjohn's RV-7

4 hours.
Today was all about the roll bar. Last time, I had the F-631A channels clamped to the plywood, ready for drilling, and I got the F-631C plate drilled to the aft section. Mostly it was about measuring. Measuring to make sure there was edge distance on the channel as well as on the strip of .063 that holds the whole kaboodle together. This was a pretty timeiintensive process. The sequence is thus: Measure the line along which the holes go, mark where the holes go, clamp, drill, cleco. Dig:
Here’s the channels jigged up on the plywood. Remember, we measured this apparatus so that it, and the attach brackets are exactly as wide as the fuselage. At this point, the channels have been marked for drilling.

To mark the channels for the proper edge distance and hole spacing, I bagged a strip of .016 (or whatever the really thin stuff is) and marked out holes with the rivet fan, evenly spaced, a little less than an inch and a half, per plans. It flexed enough to fit the curve of the channels so I could mark off the hole spacing without having to measue each one. That would have been tedious in the extreme. I love the rivet fan.

At this point, I’ve just gotten to the curvature of the channel. This is where the inner strip really wants to pull away, so I’ve got c-clamps holding it tightly against the channel while I drill. I’m using the 90 degree angle drill for this, because it rocks for this kind of stuff.

Bottom aft channel is drilled and clecoed. I repeated the process with the upper strip. This let me fit the forward (top in this case) channels to the previously drilled strip. Then I clamped, drilled and clecoed. Easier than the aft channels, because this time the inner strips are held in place and in the correct shape already.

Of course, it helps if the assemblage is clamped flat to the workspace, so that’s what I did. At this point I’m just finishing the upper left quarter.

Once it’s done, it’s a surprisingly rigid structure, which is only going to become more so when riveted. The plans have you do solid rivets on the forward section and blind rivets on the aft. I can see why you have to use blind rivets on one part of it, you can’t reach in there to squeeze or buck with all channels in place. Not unless you’re a liquid metal T-1000, but if you were, you’d be hunting down an annoying kid who’s supposed to save the future instead of building an RV-7. Anyway, here is the roll bar, wearing pretty much my full complement of 1/8″ clecoes.

Tomorrow, while the girls are eating fondue and swooning at the Oscars (Dark Knight should have got the nom, Benjamin Button blows), I will be out in the shop countersinking each and every one of those holes for flush rivets.