Saturday, December 22, 2007

Is the end near?



There are days when I wonder if I am smart enough, capable enough to build an RV-7A. There are days I wonder whether I should stop before I -- or someone else -- gets hurt in the plane I thought I could build.

This is one of those days.

I've had struggles, you may recall, with incorrectly drilling the right wing hole to the rear spar. Fixing that up took most of last winter. But I fixed it and chalked it up to just a stupid mistake.

It's taken me longer to grasp concepts of building that others seem to get almost as instinct. At times I find myself wondering if any two parts of my project will ever go together, you know, perfectly.

This evening I was working out in the garage, just sort of poking around and starting to get a little down because the crotch strap kit I just ordered from Van's has disappeared and, I presume, it somehow fell off my workbench where I just know I put it last weekend, and into the recycling, which was taken out to the curb last Monday.

"Great," I figured. "If there's a way to screw it up, I'll find it and I, once again, found it." So now I have to spend money I didn't need to spend. Par for the course. Besides, it's that time of year in Minnesota when the sun -- if it comes out at all -- reaches about 30 degrees above the horizon. We're all suffering from seasonal affected disorder up here anyway.

Then it got tragic. As I was looking at the rear bulkhead, trying to figure out how to run the strobe wires to the rudder tip, I noticed something I hadn't noticed before. Misdrilled holes.

When I mounted the vertical stabilizer and drilled it a year ago, I guess I never looked at the bulkhead after I took the stabilizer off and stored it.

Because this is a project that is now 7 years old, I'd forgotten that I drilled the holes in the rear tie down bar, and left four holes open as directed by the plans. So when I installed the vertical stabilizer, I just drilled four holes which, as you can see in the above picture, did not meet the four holes previously drilled (probably a year earlier).

I can't recall whether the holes in the vertical stabilizer spar were predrilled or whether I just did something stupid like just drilling four holes. But I clearly did something stupid and now I've got edge distance issues and strength issues all over the place. (You can click on the image for a larger view)

I suppose the only course of action here is to drill out those rear bulkheads, rebuild, and reinstall. I'll send off a message to Van's tonight.

If this turns out to be as serious as I think it is, I'm pretty sure I have to conclude for the sake of safety, that I'm not competent enough to build an airplane.

But for now, a beer is in order. With any luck at all, I can pour it without hurting anyone, although I may have to practice well into the evening.

3 comments:

  1. Bob, before you whip out and lube up the drill, give Van's a call. Since the bulkhead is just "sandwiched" they may OK it. If they don't, ok, but it's sure worth asking.

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  2. Yeah, I dashed off an email to them tonight. It's not like it's something that I've got to solve this weekend.

    Strangest thing, though, I just can't figure out where I went wrong. Maybe on the plans where it says "leave open" on the tie down bracket, they meant "don't drill." Doesn't sound right, though, so I'm figuring I missed something somewhere.

    The VS is out at the hangar. So maybe I'll ride over and bring it back to the garage and see if there were predrilled holes in the spar there. Perhaps I was supposed to backdrill through the "open holes." Man, that would've been cramped, so that doesn't sound right either.

    I won't lose sleep over it.

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  3. Bob,
    I believe your salvation is to drill the top two holes for AN-4 bolts. The bottom two holes look clean and straight. I don't think the two "extra holes" will be an issue. Let us know what Vans has to say.
    Kev, N426KF

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