gap between spar flange and skin

[CalKid]

Had a hole problem with the HZ skin along the front spar which resulted in drilling the hole to 40 and using a 1/8 rivet. When I set the rivet, because the dimple didn't quite accept the Mgf head of the rivet, the spar flange in the area of this hole is not flush with the skin; slightly curved. I see further problems if I drill this rivet out. I'm thinking build on. Any advise appreciated.

[bullojm1]

Is what your saying is there is a #40 dimple, drilled out to a #30 hole with a 1/8" flush rivet in it? if so, yeah that's a problem. Probably not catastrophic, but the fix is probably to remove enough rivets so you can dimple both the skin and the spar to #30. I can't remember is the spar is dimpled or countersunk. If it is countersunk, you probably might need a doubler on the shop head side of it.

Anytime you have non-contiguous (i.e. wavey) contact between two pieces riveted together, there is loss of strength.

[Spike]

Or if that is the case you could pull out that one rivet and replace it with an 'oops' rivet.

Spike

[bullojm1]

Is it just one rivet or a whole row of them? In my original post, I wrote it interpreting the original message as a whole row done this way. Now that I reread it (with Spikes input), if its just one rivet, the NAS1097AD4-x OOPS rivets are the way to go. They have a #40 rivet head and a 1/8" shaft.

I would order a whole slew of oops rivets - http://www.vansaircraft.com/cgi-bin/cat ... oduct=oops

If I were you, I would order 0.05 lbs of each. They will come in handy down the road.

[karles36]

When the dimple doesn't properly accept the rivet head, causing the spar flange to be not flush but slightly curved, it's often best to continue building on rather than drilling the rivet out, which may cause further damage. A common approach is to accept the slight imperfection if structural integrity is maintained, but be cautious with future repairs—consulting a specialist or reference manual is advisable to ensure safety.