Rear Spar, Front Spar

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Well, I finally started today. First thing I did was break the corners of the HS-609PP. I used my grinder, which did a good job, but got clogged with aluminum pretty quickly. I think my next big investment will be a bandsaw.

The requisite shot of before and after rounding edges.

Then I removed the blue vinyl from the rear spars (HS-603PP) and clecoed the 609s to the 603s. To do this, I needed to increase the radius of the 609s that rests against the web/flange intersection of the 603s. No big deal. Once I did this, they fit great. I didn’t finish the edge prep on the 609s, I’ll do this prior to priming everything. Then, I match-drilled all the holes, including enlarging the HS-708/HS-603PP (inboard rib attachment) holes to #21.

Rear spar reinforcements clecoed to Rear spar channels. It's starting to look like an airplane? Ha.

Next, the directions have you attach the elevator hinge brackets. After match-drilling all of the outboard brackets, they have you sandwich the VA-146 bearing in between HS-411APP to HS-411BPP.

Clecoing the center bearing supports in.

One one side is pre-punced, so you clamp, drill 4 holes, cleco, remove from the spar, and drill the rest of the holes.

Getting ready to drill.

Then I masked off special parts of the VA-146 to prep for priming.

Taped off the important stuff.

And then shoot some primer. (I’m using the rattle can self-etching primer.)

Scotchbrited, cleaned, and primed the center bearing.

Then reassemble and rivet. I found (contrary to some other builders) that the rivets called out in the plans made a great shop head. I think other builders went up a size.  I’m definitely happy with my first six rivets.

The first six rivets.

Here’s everything on the rear spar clecoed back together.

All the hinge brackets clecoed in place.

Then, per the plans, I marked the taper and radius locations for the HS-710 and HS-714 reinforcement angles.

Marked the tapers on HS-710 and HS-714 per the plans.

It was a little late to be running the power tools, so instead, I marked the bend lines on the HS-702 front spar channels. This takes some careful measurement and marking, so take your time.

I also marked the bend lines on the front spar channels. (HS-702)

Then, I strayed from the plans a little. They have you use a 1/8″ bit to create a notch relief hole, then enlarge to 1/4″ using a unibit. I used snips and then a file. The second one turned out better than the first (which I hear is pretty common on everything in the project), and I had some trouble making them look perfect. (I know, things don’t have to be perfect, but it bugs me, anyway.) Biggest lesson learned: cut the flange in the correct place first, then unbend the flange to give you more material to work with. You can see in the top one in the picture below that I didn’t do this, and had to taper into the bend relief notch. (The bottom one below is better, nice straight line back to the relief notch.)

Finished HS-702 shaping with bend relief notches.

Then I bent HS-710, HS-714, and both HS-702s. I created a cardboard template using trigonometry. I took the tangent of 6 degrees. Which is a little over 0.1. (This means fromthe bend line, for every inch you go laterally, the angle will be just over 0.1 inches up.) That’s a little hard to measure, so I took the inverse (to figure out how many inches laterally I need to go for 1 inch up), and got just over 9.5 inches. I have a calibrated 6 inch ruler, so I divided by two, and ended up with mike’s numbers; 4.75″ over, and 0.5″ up.

Now that I have my template for six degrees, let’s get bending.

After trying a few methods in the vise, I ended up just lining up my bend line with the edge if the table, holding a wooden block over the piece, and putting a little pressure on it. If you go slowly, you can get 6 degrees pretty dead nuts on. I laid everything on top of eachother, and it all lined up very nicely.

Lastly, I finished the front spar section by dimpling the HS-702s, and countersinking (first ever countersink!) the HS-710 and HS-714 for the center two holes only. Remember, flush rivets go on the aft side here, so the countersink and the male dimple die go from back to front.

Countersunk HS-710 and HS-714, dimpled HS-702.

A solid 5.5 hours today.

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