Tue May 20 2008

Modifying F-716 center ribs

After Kerin helped me move the tailcone off the saw horses, I decided to tackle something that has been bugging me for a while. The two forward and aft center section bulkheads didn't seem to match up in width. Here you can see that at the top, one is wider than the other.

...it's about 3/8 inch difference. I dunno how, but I think I must've riveted on one of the vertical members crooked.

In order to figure out where the problem is, I ran four bolts through both center section bulkheads so they would be lined up.

Gah, it turns out that one of the bulkheads is supposed to be narrower than the other because the fuselage is tapered at this location. Duhhh. Well I took the bolts out and set them aside. At least I have some peace of mind now.

Next on the docket was to modify the two center section F-716 L and R ribs. The plans have you cut a notch out of each one and rivet on a little doubler to allow the control column to be removed. The cutout piece ends up being screwed in place, and I figured it'd be a lot easier to match drill before cutting the notch out, so I did that first.

Then it was an hour or so with the band saw, dremel, and assorted files until I had everything cut out and deburred. Not bad for an evening's work. Maybe I'll modify the other two F-716 ribs tomorrow night.