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Elongated Holes on Elevator Spar

S

Sugar Dunkerton

Member
Hello all, I have been lurking here for over a year and have been getting through much of my RV-9 taildragger empennage.

I had some trouble fitting the WD-605 elevator control horn to the E-902 elevator spar and E-906 rib. It seems the bend in the flange on the rib is not quite right, and the holes in the spar don't line up with the control horn when clecoing it together. Per previous posts by other members, I massaged it together, clecoed and drilled it, but the holes on the spar side are elongated. The widest part of the hole measures .152"

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I figure I could:

A: Rivet it together as is.

B: Use #5 size rivets.

C: Fabricate a doubler plate and use longer #4 rivets.

I've also emailed support at Vans, but was wondering what solutions the forums would produce.

First post and photo test, thanks for reading.
 
Here is my take:
A exceeds rivet hole diameter
B is a good option if edge distances can be maintained
C will require additional rivets between the bad holes to secure the doubler to the spar. Otherwise the spar just floats between the horn and doubler and could "work" over time. (Doubtful, but it is not "correct" practice.)

I have filled an oblong hole by fattening up a -4 prior to setting but I would not recommend that in this case as the horn to spar is a critical area.

As you found out, it is very easy to oblong a hole in aluminum when the mating part is steel. Forcing things into assembly is not necessarily the best advice. If the don't match up, figure out why and fix it.
Still, if this is your worst mistake, you got it easy.
 
JonJay said:
...
I have filled an oblong hole by fattening up a -4 prior to setting but I would not recommend that in this case as the horn to spar is a critical area.

.....
Click to expand...

Probably not a good idea in this case since the oblong bit is only in one layer and is not the shape of the entire through hole.
 
I did the same thing, with very similar dimensions, on the rear spar of my 7A wing. In fact mine were worse: 0.150 in one direction and 0.165 in the other direction. The response I got from Van's: "A couple of -5 rivets is ok. You probably could use -4s in these holes --they aren't that bad."

Of course bear in mind this was a different area of the airplane. I ended up drilling out the holes with a #21 and driving #5 rivets. That was tough with a 3X gun, by the way. I also thought about a doubler plate, but since they said even -4 rivets would be OK... I just used the -5s for a little extra peace of mind. Fortunately one of my local friends had soe extra -5 rivets so I dind't have to order them (thanks, Doug!)
 
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