Rear spar

Two weeks ago, I left off getting ready to match drill some of the rear spar double plates.  I spent last Saturday at the doc-in-a-box waiting (and waiting) to get a prescription written.  Sigh!  I dove right in this Saturday and got all the match drilling done.  Watch the holes carefully, it is easy to miss one.  I almost did, but caught it when I double checked.

2015-06-27 11.28.56

One of the doublers needs a cut out for the aileron push rods.  Vans provides templates.  Since I have the PDF files for the plans, it was pretty easy to just print out those templates.  Do be careful that they are printed at 100% size.  My son came out to help (and get some lunch at the Chinese restaurant!).  I mounted the templates on the doubler plates (I just clecoed them in place) and he drilled the pilot holes on the drill press. Since the clecos raised the plate up a little, I used a leftover piece of styrofoam as a waste board.  The clecos pressed into the foam leaving the doubler plate level for the drill press.

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The original instructions have you drill a pair of 1″ and (it says 3/8″ but is really) 3/4″ holes and then clean up the edges.  The newer instructions have you trace the outline of the aileron push rod hole.  I did it the original way (mostly).  I used some spade bits to cut the holes and then cleaned the edges up with a file.  It came out pretty close to the original hole.  I think the new method would have been easier… maybe drilling a bunch of #30 holes just inside the perimeter and then filing to shape.

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The next tedious step was deburring and edge filing.  Most of these I handed off to my son.  He did a great job and it really sped the work up.

I got everything primed.  There’s still some match drilling and countersinking to do, so there’s a bit of touch up to do.  Easier to have all the pieces primed now for handling.  I assembled both rear spars.  Next time out, I’ll finish the match drilling and counter-sinking and I’ll rivet these up.  Maybe I’ll even get a couple of top skins clecoed on!

2015-06-27 17.31.40 2015-06-27 17.31.27


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