Wednesday May 13, 2020
Drilled the Rear Spars to the Fuselage! (Mating Wings)
6.0 Hours

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Today was the day to set the angle of incidence on the wings and drill the rear spars. I made a little 3" block in order to construct the jig for setting incidence.

Here it is, seemed to work well.

With just a little tweaking of the wings up and/or down, I had agreement on both sides.

I made a little drilling guide out of a block of hardwood so I could drill these holes straight.

I drilled the holes at 1/8" first, then enlarged through 3/16" and 1/4" before drilling to final size at 5/16.

The bolts sit very straight on both sides.

Looking like a plane!

Edge distance was no problem, but it is interesting that the right wing sits about 1/8" higher at the rear spar attach point than the left. I think this is due to some twist in the right wing. I re-checked the wing incidence after drilling and bolting and it isn't as perfect as in the images above, but the two wings are within 0.1 degrees, which should be just fine.

This will probably cause some issues with the flap sitting flush against the fuselage, but not a big deal.

I drilled the fuselage bottom skin to the wing bottom skins on both sides. These are #19 holes for #8 screws. I'll dimple the holes and install nutplates on the wing when it comes off.

Then I got to work on the fuel tank attach plates. The steel had some superficial corrosion from sitting around for 10+ years, but came off easily with light sanding.

It turns out I installed the angle that these bolt to on the inside of the fuselage already, so this was pretty straightforward, just cleco them in place and drill the bolt holes to size. Then I marked and drilled the hole from the wing plate to the steel fuselage attach plate. They both came out great.

I removed some access panels in the baggage area so I could see the flap weldment.

You can see the empty hole that will need to be enlarged to pass the flap control arm. I can't fit the flaps until the parts I need to mount the ailerons arrive.

I primed the two steel brackets.

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