Rollbar Match-Drilled

Don from Texas had brought up a very good idea for the match-drilling of the rollbar. He suggested to hold off on that until the rest of the structure it connects to through the center rollbar brace has been put in place. That way you are sure that the alignment of the rollbar is correct. Apparently, a lot of builders found out later that the rollbar had to be pulled back a little to match the rest and that's a bit hard to do when you already riveted it to the bases at some defined angle.
I thought that was a great idea and so I did not start with drilling today but by putting the aft area of the fuselage into place. In order to do that I had to rip open the sealed off tailcone as two parts of the aft bulkhead were needed to match drill a little bracket tab in the front of the tailcone.


I was very pleased to find nothing in there that wasn't supposed to be in there. The seal had worked well it appears. Unfortunately, the 3M cream painter's tap eI had used when running out of blue tape had deteriorated tremendously over the time and did not want to come off clean. I had a very hard time even with MEK to remove the residues from the aluminum. Lesson learned, never use the creamy tape again. It's 3M but some nasty crap anyway.

After this cleaning session I fitted the bulkheads onto the fuselage. The little cutout for the longerons are very tight and I used a hand deburring tool to shave off tiny layers of metal in that cutout until it easily slid onto the longerons.


By the way, see that perfect fit? Not just the cutout, I mean how nicely the flange follows the side skin? Well, there's an ominous request on page 24-05, I believe, that asks for fluting the 3 flange segments below the cutout on both bulkheads until the holes in the flange mate the ones in the side skin. I found that weird from the start as the side skins are pretty much flat in that area and so are the flanges. You usually have to flute when something follows some kind of arch.
So I did nothing and just clecoed this one in place to see if there was some fluting required. I didn't see the slightest hint to do anything on either side. Do you?


Maybe Van's did it at the factory. When you look very closely you can see a little dent in the middle of the middle flange. I didn't do that. So maybe this step is not required anymore, just like the one that suggested you should separate the bulkheads from one initial piece. That step was obsolete either as Van's had already done it for us.

Anyway, I clecoed the aft part of the structure together and put the rollbar brace on top. This is how it looked without changing anything about the alignment of the rollbar.


A little closer and taken from the plane of the aft bulkhead...


...reveals that this is pretty straight and doesn't look like it needs any adjustments.

I tried to wiggle it around but the rollbar wouldn't want to move at all, so I figured that this is perfectly aligned and I went ahead and drilled the bases.


The inner holes were a little odd to get at but it was manageable through the opening in the aft bulkhead.
Well, that concluded the day. It was already past 9pm when I took that photo and I left the cleanup of the chips for tomorrow or whenever the next session is going to be.