I struggled to get the F-776 bottom skin onto the centre section. I tired a couple times to get it cleco'd working front to back, but the holes were just too off when transitioning aft of the F-705 bulkhead. I then disassembled and tried starting in the middle at F-705 but when I got to the F-704 center section assembly, the holes were again too off. I double checked my assembly, the F-916 spacers were in.
The issue I seemed to be having is that the radius of the F-716 seat ribs is not tight enough and this is reflected in the fit of the ribs to the F-704 center section. The holes do not line up by themselves, however with some hand pressure they line up.
I need to figure a way of squeezing this up.
After some head scratching I thought of clecoing the top row and bottom row first...this will help evenly squeeze the assembly as I celco'd row by row to the middle. As I started, the middle of the skin was a bit proud off of the F-705 bulkhead as the tight skin wanted to bow the structure the opposite way.
After a few more rows of cleco's, holes were starting to line up very well. Still tight, but much better than they were. So I clecoed the middle rows.
And just like that, the skin went on. Whew!