Uhmmm - uh oh. Help? Please?

I'm to the point of initial assembly of my right wing on my 9A, fitting the main ribs for matchdrilling to the front and rear spar. When I clecoed in the main ribs, they match up perfectly on the bottom of the front spar, but on the top of the front spar there is an angled gap that is consistent on every rib for the length of the spar. It looks just like the spar flange has been under-bent, or the ribs are too wide and are spreading the top spar flange away slightly. I can force the flange in to fit by hand, but it takes quite a bit of force and I'm not quite kosher with this being correct. Can any one here provide me some guidance? All the ribs have been straightened, deburred, and fluted and look beautiful when laid on a flat surface.

This first image is the top flange of the front spar, outboard end.


This image is the bottom flange, outboard end - it mates up just fine.

Maybe double check that you have the top/bottom orientation on the spar correct- if I recall, there is a difference in the doublers.

Be extra carefull that you either do not have the spar upside down or that you are using the wrong ribs in the wrong orientation. There is a difference in the right vs the left spar! Look for the inspection cover holes that are pre-punched in the spar flange. They should be down! If they are, look at the orientation of the ribs very closely! Just because a rib is marked XXX-L or XXX-R does not mean that it goes only on the left or right wing.

Tripple check!

Brantel said:

Be extra carefull that you either do not have the spar upside down or that you are using the wrong ribs in the wrong orientation. There is a difference in the right vs the left spar! Look for the inspection cover holes that are pre-punched in the spar flange. They should be down! If they are, look at the orientation of the ribs very closely! Just because a rib is marked XXX-L or XXX-R does not mean that it goes only on the left or right wing.

Tripple check!

Click to expand...

You're exactly right - each wing gets a mix of -L and -R ribs. I double- and triple-checked the rib type and location, even had my wife come help me ID the ribs and verify locations to put another set of eyeballs on it. I double-checked the spar top/bottom orientation, all is as it should be. I was actually hoping I had missed something stupid like that so I wouldn't have to go public begging for help, but it is what it is. The more I think about it, the more I believe I just need to pull the flange in a bit by hand/cleco/clamp while riveting, but I want to get that straight from Vans before trying it.

I've also sent the photo's to Vans and I'll be talking to them in an hour at 1530 local when the builder hotline opens up.



Update - issue is resolved!

I was correct, I had all the correct ribs in the correct locations, top/bottom orientation was correct etc. - the upper flange on the spar is under-bent. Per Joe and Scott at Van's, this is unusual but not unheard of. Here is a pic of the top flange of the wing spar with a square on it, you can see it's not bent to 90-degrees as it should be.



The solution is simple, get a length of 2x4 and cut a slot in it as deep as the flange is, clamp the spar down securely on something, and use the 2x4 as a "wrench" with the offending flange fitted into the slot to slightly bend the flange back into it's correct position, working your way down the full length of the spar. No, I didn't make this up - Vans really just told me to take a 2x4 to my high-dollar wing spar....