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Misaligned holes in elevator tip ribs

StressedOut

Well Known Member
I'm trying to do the final drill of the #40 holes between the E-913 counterbalance skins and the E-903 and E-904 tip ribs. I'm having a real hard time trying to get some of the holes to align. I've contacted Van's technical support already and gotten a response, but their suggestions haven't worked so far. I thought I'd throw this out to the VAF and see if anyone has experienced this same issue.

I've done the fluting of the E-903 per page 09-02, step 5 and it's pretty flat. The E-904 rib came fully fluted from the factory, but it wasn't very flat. There was about 0.200 in. out of plane, so I "defluted" best I could to bring it back to flat.

When I cleco the assembly together, a group of holes are misaligned by 1/3 to 1/2D.

Has anybody experienced this and more importantly, how do you deal with it? Sorry for the giant picture. I'm not sure how to reduce its dimensions.
p5efGob.jpg
 
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Did mine last week. No issues. FYI a tip I discovered last night. You need to remove a lot of material from the lead weights that bolt to the counterbalance ribs. Buy a milling tip used in a die grinder but mount it in your drill press and use it like a mill. No issues with lead dust you might get if you saw it
 
Did mine as well the last couple days. Haven?t finished the right elevator yet. However I found that the 903 and 904 ribs were straighter before i fluted them. I decided to man handle them a bit by twisting them then they actually laced flat on the bench.. Then clecod them together and they fit almost perfect.
 
You are not alone. It is an #itch to make these fit.
However, there are few tips: a) try rib flange tool and then flute again
b) cleco all holes connecting e-713 to 703 and 704, match drill #30 only 703 and 704 then rivet together using AD4-4 , c) take apart and then assemble with the rest of the elevator including counterweight using all holes connecting E-713. In my case at this stage the holes aligned to a degree where I can somewhat accept it, not without grind of my teeth. Now you can match drill removing one cleco at a time and replacing clecos back after match drill.

Judging by your status update you are trying too hard to make it perfect.
So did I. I am not happy with the way counterbalance parts are designed and manufactured but way too many people do not find that disturbing.

So perhaps that's the way it meant?

Obviously your prefix is 9 for each part.
 
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You are not alone. It is an #itch to make these fit.
However, there are few tips: a) try rib flange tool and then flute again
b) cleco all holes connecting e-713 to 703 and 704, match drill #30 only 703 and 704 then rivet together using AD4-4 , c) take apart and then assemble with the rest of the elevator including counterweight using all holes connecting E-713. In my case at this stage the holes aligned to a degree where I can somewhat accept it, not without grind of my teeth. Now you can match drill removing one cleco at a time and replacing clecos back after match drill.

Judging by your status update you are trying too hard to make it perfect.
So did I. I am not happy with the way counterbalance parts are designed and manufactured but way too many people do not find that disturbing.

So perhaps that's the way it meant?

Obviously your prefix is 9 for each part.

Alex,

Thanks for the reply. I'm not trying to make it perfect. I'm just trying to make it acceptable. The holes are too far off. I'm not a big fan of figure 8 holes and that's what I'll have if I do the final drill.

I've been investigating the issue over the last week and believe the problem is due to the bend line of the flange is slightly off. I have some photos that show a decent size gap between the ribs and the counterbalance skin when everything is clecoed together, excepting of course those holes that are misaligned. I need to figure out how to make the photos smaller before I post them here.

I've thought about oversizing the holes, but a -4 rivet isn't big enough. I need at least a -5 rivet to cover the mismatch. I don't have dimples or rivet sets that big and I'm not even sure a NAS1097-5 rivet can be used in a -3 dimple. Then there's the problem of positioning the drill to catch both holes.

I've tried most everything I can think of to fix this within the tooling I currently have on hand. I've tried different matching of parts and the problem is a little worse. If I had an undrilled E-904 rib I could just match drill, but I understand why it's not practical for Vans to supply a couple of them just for me. Too many tooling and/or CNC programming modifications would be required for a one-off.

I'm still thinking this through. New parts will run about $75, but I don't really want to spend that money yet.
 
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