[ScottK]

I'm working on the rudder, dry fitting the counterbalance skin (R-913) on the two ribs and spar, and it just doesn't want to fit. I've checked the ribs for straight and square and I've gotten most of it lined up - by force on some holes - but with everything else in place, two holes across the front, one on each rib, are still like 1/3 of a hole out of line. As if the ribs need to be narrower than they are. Enough that if I drilled it I'm not sure it'd be OK to hold rivets. But the skin is tight to both sides of the ribs and snug across the front. I know Vans never makes errors on pre-punched parts, so I'm not sure what I'm doing wrong.

 

[PilotjohnS]

Curious

I dont remember having holes mis aligned, but I do remember I played around with skin stackup and had to flip a rib around to make things go.

Maybe some else can remember more details, or if you post a pick, it will be easier to figure out what is weird.

 

[Jslow2]

i had to flute the ends of the ribs to sit flat against the end of the skin, they were quite curved.

 

[ScottK]

i had to flute the ends of the ribs to sit flat against the end of the skin, they were quite curved.

Ah, that's something I noticed too. I actually put a little bit of a curve into the skin to try to allow for the rib flanges - I guess that's the wrong answer! Happily, a shallow enough curve that I can take it back out. Fluting the forward flanges would solve it though. I just didn't want to make those permanent fluting bends without good reason. I'll give it a shot.