Finishing Kit

June 7-8, 2011

The Canopy Frame - continued - 2.5 hrs.

Well, over the last week or so, I had little time to work on the plane, but popped out into the shop every chance I had to just look, think, and study things. I'm trying to decide if I'm ready to drill the hinge goosenecks, or not. There are so many variables with this part of the project, so many things can change, it can be kind of nerve-wracking to know if you've done everything you can to make things fit and work correctly. It didn't help me any, to hear from a chapter member that recently finished his RV-7A with a tip-up, that his canopy didn't fit very well when he got everything finished. It looked good to him when he was at the stage I'm at. But he says when he riveted the top skin on and finished everything up, it didn't fit right at all. NOT what I needed to hear right now. Nevertheless, at some point you have to make a decision that you've done everything you can and you move forward. Gotta git 'er done.

So I decided that it's time to move ahead and drill the hinges. I spent some time very carefully positioning everything as exact as I can get it, using my ratcheting tie-down strap to snug things down into place. Honestly, I'm comfortable that I've done everything humanly possible to get this to fit as best as I can. I finally figured that worst case, it doesn't fit quite right, and that just means more time with filler, bondo or whatever, and lots more sanding. So let's go. Here's my final positioning:

And another shot from the side:

The plans tell you to drill through the hinge-pin blocks into the gooseneck hinge arms just enough to mark the hole all the way into the metal, but not drill all the way through. How do you drill this thing? Well, I got out my right-angle drill with a 1/4" bit and reached up through the firewall opening and did it that way. It's cramped a bit, but definitely doable. I didn't get any pictures, though. I couldn't see a way to drill and take pictures at the same time. Anyway, I put what I figured was a good dent in each hinge gooseneck, because you're drilling blind and can't tell how far you've gone. Then I took everything apart. Here's what I had done:

I was pleased to see this because there's no way to know, just by feel, if you drilled deep enough or not. It looks like I got it just about right. The trick now is to figure out the best way to drill this 1/4" hole open to 3/8" for the hinge bearing that goes in here. In anticipation of this, I went out a few days ago and bought a 23/64" drill bit. I figure I'll step up gradually from 1/4" to 5/16", then to 23/64" and finally finish the hole with my 3/8" reamer. I have also fab'd a drill block, to clamp on and make sure the drill bit is straight and perpendicular to the surface while drilling. I'm trying to do this as carefully as I know how, because it seems to me that if you mess up this hole even a fraction of an inch, it can cause the whole canopy frame to shift one way or the other and not sit straight. It's the same feeling I had when drilling the rear spars of the wings to the fuselage. And I thought I was done drilling critical holes. So anyway, I'll be tackling that next.

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