April 30, 2006

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	Hours Today: 1.3	Project Total: 118.0

(8-5 step 2): Today Angela jumped right back on the horizontal stabilizer front spar. She clamped one of the HS-1013 front spar caps to the front spar making sure it "covers the thirty-third hole in the end of the spar flange"... basically it was centered on the front spar. After checking for symmetry she match drilled the flange holes 1/8"... unfortunately she would later realize this was incorrect :-( Turns out she had read, re-read... and then re-re-read the plans before putting drill to metal. She then told me she found out the hard way that this doesn't work so well days before the operation (doh!) Mental note... not only will we re-re-read the plans prior to any 'metal removal'... we will make sure to do it just prior to metal removal! The end result is we have one spar cap & the front spar with 1/8" holes in the flange along the entire length of the spar cap. These are holes that will eventually attach skin, so I think we can get away with it (albeit with bigger rivets!) but we'll shoot an email to Van's tech support first just to make sure.

(7-11 step 1): Angela lost a little motivation after the mis-drilling incident so she decided to go on to other things for the day. Meanwhile, it was time for me to jump into what I've heard is a tedious process... riveting the trailing edge. Well, yesterday I tried clecoing the vertical stabilizer skin to the skeleton and found out none of our clecos would work in the holes... they simply popped right out. Long story short, it turns out the holes were slightly oversized (I measured them and they were about .003 over the max described in MIL-R-47196) I think this was a result of overzealous dimpling because I measured some of Angela's & they measured fine. Anyway... The holes in the trailing edge of the rudder were also slightly oversized and the rivets seemed to swim around in there. I found some hints regarding this situation, and decided on one I liked the best... I took a rivet that was 1/2 size longer than that called for, and 'pre-squeezed' it down to the height called for. This enlarged the shank just enough to better fill the hole, while leaving the rivet short enough to guard against bending when bucking. I didn't have a bunch of time tonight, so I squeezed enough rivets to get the trailing edge done plus 2 just incase. I'll rivet the trailing edge tomorrow...