Friday October 1st, 2004|
First today I started out drawing centerlines in the flanges of the tank attach z-brackets. Very boring, tedious stuff. I usually end up doing this sort of thing at the kitchen table, where I can sit and the light is better and I can chat with Jaime, etc.
Then the plans have you cleco the brackets to the spar web so that you can drill the top and bottom holes. I had a small problem here with my #12 bit. I think the thing must be shot or something cause it will not start a cut into the metal very well. What I ended up doing was drilling out the holes with a #30, then a #19, then the #12. That worked.....hmm...ok.
And next was deburring, countersinking and riveting on the platenuts for the screws to attach to them. I went and screwed the brackets on the spar, per the instructions.
Then I started thinking about how silly the plans are here. I've heard that the plans have problems here but it never registered to me what exactly people were talking about. The problem is that every other part involved in the tank attachment is prepunched (except the brackets and the joint plate that attaches the tank at the outboard edge to the leading edge). In other words, if you don't drill EXACTLY, PERFECTLY on the centerline, the tank baffle (the flat, vertical aft portion of the tank) prepunched holes will not line up, which was my problem . Actually, I was able to get the clecoes in without much effort, but then I clecoed on the baffle and then the tank skin. My intention was to simply gauge the gap between the tank and outboard leading edge wing skins. Well, the alignment aboslutely sucked. It was off by about 1/8 or so, which is just a glaring hole. It's not like you just just throw a little superfil in there since this is the tank and chances are it will have to come of the wing at some point and breaking such a seal would...well...it would suck.
So, I've decided that tomorrow I'm going to steal Dan Checkoway's idea for drilling these brackets.