05-04-2008 - Aft Spar Ends


According to the plans the rear spars are to be drilled for the ribs.  The ribs supplied in the kit are drilled from the factory - so be sure to lay out your holes carefully.  I decided to make a template to make it easy to layout the holes.



I just took some of my cutoff scrap and bent a lip on it to index it with the top of the spar material.



I measured the location of the top hole on the spar and transfered the mark to the layout tool.



I measured the remainting three lines based on the dimensions shown on the drawings.  Fortunately it lines up with the holes in the back of the ribs perfectly.



The aft spar hole "layout jig" marked and drilled.



The first marks made with the layout tool.



The picture is a bit fuzzy, but the marks line up perfectly with the ribs.



Cutting the 36" piece of aft spar channel supplied with the kit for the aft spar extension pieces.  I still use the miterbox to cut the channel - its pretty much the easiest, most controlable method.



A nice straight cut - easily cleaned up on the benchtop sander.



The right aft spar extension tip marked for cutting and drilling.



Using the bandsaw to cut the 45 degree angle.  I cut a 45 on a 2x4 to support the channel while cutting it.



I used a 1/2" bit to put the 1/4" radius on the hole for the aileron counterweights.



Not quite perfect, but after cutting it out and filing the opening it'll be pretty durn close.



I started out with the cutoff tool in the dremel and then remembered I found my nibbler last time I was arranging my toolbox.



Handy tool - I bought it when I was in college for cutting out a enclosure for a power supply project.  It's been sitting in my electronic toolbox since.



I clamped the channel down and filed/sanded the opening to its final size.



The 45 after sanding it straight on the benchtop sander.



The completed aft spar extension.



The other side of the extension.



When cutting the 45 with the bandsaw it cut the lower flange at a bit of an angle because of the bend in the metal.  Other than the cosmetic issues under the finished wing, I don't think this will be an issue,



The left aft spar extension marked for cutting drilling.



Drilling the hole for nibbling.



The nibbler cuts a fairly straight line.  It won't take much filing to clean that up.



Nibbled - ready for filing/sanding.



Filed and sanded - this one is a bit straighter than the first one.



The completed aft left and right extension tips.



Marking the right spar channel for the rivet layout.  It is important to mark which way is up because the difference in angles.



I used a steel tape measure to layout the rivet marking locations.  



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