22/07/2017 - Matchdrilling aft top skin F7112.

Little pictures during work today as it isn't again all that visual. I clecoed the aft top skin F-7112 in place.
Some remarks on that: don't forget to install also the F-787 stiffener web and the F-788 gusset plate underneath the skin.
They will also be matchdrilled in the same process as matchdrilling the top skin.

First I repeated the same process as with the J-stiffeners yesterday on the rear top skin.
Check the centerline through the holes and drill ever 3th hole continuously checking the position. Then drill the remaining holes and cleco as you go.

Next was matchdrilling the F-787 stiffener web from back towards the gusset plate.
Last matchdrilled the F-788 gusset plate.

Then matchdrilled all the bulkhead holes and the longeron line.

This was kind of like a cool shot so couldn't resist adding it in the blog.

Last step in the matchdrilling process of the top skins is the installationg of the smallest bulkhead, the F-709. I primed this in a previous priming session so it's all ready to be installed.
I had to flute the flanges of the bulkhead to bring them in alignment. The fluting is pulling the flanges in and by that also creating small overlaps between the different sections.
This will have to be filed away before final installation. I checked the bulkhead multiple times until I got the right angle on the flanges so they lay nicely against the top skin.

I also found that the bottom of the F-709 was very thight agains the longerons and that this would be a potential scratch place with vibrations so I grided a bit away from the sides where the F-709 touched the longeron.

The last flange of the F-709 has no predrilled holes yet. I marked the location with a sharpie pen while it was in place and found the following positiong of the holes.
Plenty of edge distance