<January 4, 2008>
Fluted F-715 Seat Ribs
With the baggage floors drilled and clecoed, I turned my attention to the F-715 Seat Ribs. These are the outboard two ribs and they curve a bit to conform to the contour of the fuselage. To get them to curve, fluting is in order, heavy fluting.
First things first. I marked a line where I wanted my rivets to be. This isn't exactly centered on the flange, but is weighted a touch towards the web. Why? Not sure, it is just where I put it. Actually, IIRC I measured where Van's puts the holes in the prepunched ribs and used that dimension.
Next I had my father-in-law hold the rib in position (roughly), and using the holes in the bottom skin as a guide, I marked the locations of where I wanted to flute (between the holes in the skin). Clear as mud?
I found that I had to trim about 3/16" off of the front flange of the rib to allow it to sit inside the F-704 Bulkhead properly.
After fluting the bottom flange of the rib, I slid it into position parrallel to the holes. Wow, I came pretty darn close to perfect on the first attempt.