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F-7108A Forward Center Fuselage Rib, DWG 24

wirejock

Well Known Member
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I believe the reason for this is slider vs tipper. The firewall is common to both but can'tbe drilled because the substructure is different. Therefore, the rib can'tbe drilled either. Solution will be posted to the "Gotchas" page.

7a Slider
I'm building the cabin forward. The manual says to drill F-7109 Plate and F7108B Angle to F-7108A Forward Center Fuselage Rib. There's a problem there, but that's not the reason for the thread. I'll discuss that below.
Next is says to assemble F-7108A Forward Center Fuselage Rib with F-7105A Sub Panel then cleko the assembly to the Firewall. Hmmm. That's rather difficult since there are no holes in the flange of F-7108A Forward Center Fuselage Rib or the Firewall. I know how to resolve the problem, I just want to make sure this is normal and I'm not missing something. All the drawings clearly show zero holes in the Firewall for F-7108A Forward Center Fuselage Rib. DWG 24 clearly shows holes in the flange yet none exist. Who took my holes? Maybe they're "virtual holes" :D
First, I can't drill F-7108B Angle to F-7108A Forward Center Fuselage Rib because the hole into the Firewall Stiffener has to fall in exactly the right place or the Rib won't be in the right place and skin holes won't line up.
Second, I can't arbitrarily drill holes for the rib and firewall for the same reason.
So here's the plan.
I clekoed everything together including the skin. Basically I'm using the skin to pull everything into it's proper location. Now F-7108A Forward Center Fuselage Rib and F-7108B Angle are located correctly and the hole for the angle can be marked on the stiffener and the flange of the rib marked on the Firewall. Then I will disassemble and check the marks to make sure there are no edge violations. Next, I will butt two ribs together and match drill F-7108A Forward Center Fuselage Rib, reassemble and mark the Firewall for drilling or maybe I can find a talented monkey to send in there to drill them from the inside.
By the way, the Forward Top Skin is a real beast to install. I'll post a thread to the "Gotchas" page for all of this including one for the skin install later. It's clekoed in place overnight to take a little set so it's not such a beast to install again.
So, are the missing holes normal of did someone steal them? :D
Maybe Amazon has a deal on holes. :D
 
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I remember this area well, Larry. You aren't missing any holes. :D

LOTS of installing top skin, fitting/drilling/cleco parts, remove top skin rivet parts, repeat. It just takes a lot of time to piece it all together because some parts rely on the installation of others for proper fit. A friend had a steel block he countersunk to the appropriate depth, which was used on the inside of the firewall with a monel rivet on the outside. Hit a few times with your rivet gun and you'll have those holes nicely countersunk.

When it was all done and the top skin riveted, all fit well except for the roll bar brace (WD-643). I ended up having to re-drill the top hole to get the bolt in. I'm not sure it could have been avoided since that bolt must be in place for fitting everything else but I would recommend using a smaller, temporary bolt, then drilling to final size after the fwd top skin is riveted.
 
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Thanks

Thank you Ray. Nice to know I'm on the right track.
I made a set of bars for that sort of thing. They really come in useful. 3/16" hole holds dimple dies. I drilled an old flush set as well so the dies fit the gun. I dial the pressure down and feather the trigger to get one or two taps and dimples come out nice.
 
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