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Hornet2008

Well Known Member
I was match drilling the skin through the J stringer into the F-779 skin. It was hard enough trying to keep the centre line of the J stringer in the centre of the side skin (F-773) hole of the tail cone let alone line up the hole in the F-779 on my RV 9. This was the result, figure of 8 holes and oversize holes
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The second photo is an overview of the two rear bulkhead and tail wheel spring assembly. The problem is the horizontal holes on the F-779 tail cone skin.
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I have emailed VANS. I am thinking of drilling out the holes to #30 and using a 4 oops rivet. Not sure of my options here and are asking for advice. Many thanks in advance.
 
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I think you should either replace the skin or step up the mis-drilled holes to a -4. Using a single 'oops' rivet in a line of 10 rivets may be ok, but you cannot use all 'oops' rivets in place of standard rivets due to the reduced head contact area and resulting lower tension strength. This would definatly not be a good place to have a bunch of 'oops' rivets as this is highly stressed area.
 
Had the same thing happen on one of my holes. Went to a -4.

FYI - I found it was a *lot* easier to get the skin to fit if you put the skin on the tail section first, then fit the bulkheads. Mine's a nose dragger so that might not work in your case.
 
Van's will give you the definitive answer but I think Walt has pretty much said what my advice would have been and why. Personally, I wouldn't want to be flying a plane and knowing those oversized holes were there. As I recall (i.e., this is from memory) that the aft skin is thicker (0.40 rather than 0.25) than most of the fuselage skins. That lends a lot of credence to Walt's observation that this is a stressed area. My opinion - worth every penny you paid for it - is replace the skin (and get new J-stringer too).

Again from memory, I marked the center line of the J stringer with a Sharpie, then held the stringer in place while I drilled through the skin from the outside, piercing the sharpie mark. IIRC, I drilled the first hole near the middle of the stringer to start. Then I put a hole and a cleco in both ends, then filled in the middle hole. This let me drill from the outside and use the prepunched holes in the skin for alignment against the sharpie line on the J-stringer. No figure 8 holes this way.
 
Don't replace the skin if a #30 hole will get things round again. Just drill it up an dimple for a AD4 rivet here. So long has you have proper edge distance this will be stronger than both an AD3 rivet or an oops rivet. Let us know what Van's says, but I will bet they will not tell you to replace it.
 
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Vans reply was "yes, just drill them out to a #30 and install some NAS1097 Oops rivets" Think I will get a new skin.
 
Both of my F1 Rockets utilized long rows of 'oops' rivets in the skins by design and per the plans.....just sayin' :rolleyes:.

In the OP's case it would drive me nuts just thinking about those holes back there.....I would absolutely get new parts and live happily ever after :).

Walt said:
Using a single 'oops' rivet in a line of 10 rivets may be ok, but you cannot use all 'oops' rivets in place of standard rivets due to the reduced head contact area and resulting lower tension strength. This would definatly not be a good place to have a bunch of 'oops' rivets as this is highly stressed area.
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rv6rick said:
Both of my F1 Rockets utilized long rows of 'oops' rivets in the skins by design and per the plans.....just sayin' :rolleyes:.
Click to expand...

The key word here is "by design", if the engineer specs it that way then fine, thats not the same as the builder randomly replacing "specified" fasteners with substitutes of his choice.
 
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