Drilling various gussets^2.5h

Drilled some gussets today.

I started with the forward fuselage gussets, F-695. These parts are known for not matching the angle perfectly, so I sanded them a little bit. It does make a part just a tiny bit shorter, though, which then requires changing the location of the holes on it.

Also, the overlap between the longeron and the engine mount is about 1/2", so a perfectly located hole would get an exactly 0.250" edge distance. Not too much to work with!

There are a total of 14 holes on the long side, which I placed with an equal spacing of about 1/2".

However, in the end, I found that the first one of the last four holes was exactly at the edge of the engine mount (see the left blue dot).

I could have moved the gusset a bit aft so the rivet clears the engine mount (the right blue dot) but decided to replace the part instead. Since I only drilled the part and not the fuselage, it's not a big deal.

Here is another view of the gusset:

For the right side gusset, I drew the line where the engine mount ends and made sure that I have enough edge distance both for the first longeron-only rivet and the last rivet on the engine mount.

Then I moved on to the aft fuselage deck. Not much there. I checked that the fuselage is straight and doesn't have much twist in it, both using a bubble gauge and a digital inclinometer. Then I drilled the holes in the aft deck.

Finally, I drilled the holes in the F-757 plate. 5 holes are shared with the F-721B canopy deck and the longeron and 3 holes are the new ones. After I drilled the aft three holes I was researching the supertracks extension and saw that these three rivets are flush rivets whereas the plans show AN470AD4 rivets. Then I realized that even though the locations of the rivets are given on the tip-up variant of the F-757 plate, the rivets for the sliding canopy are indeed the flush AN426AD4 rivets. Tricky-tricky!