Wondering how everyone dimpled the nutplates on the inboard wing, Section 16, Top Wing Skins(New Numbering, I think the old was 14). Did you dimple through all three pieces together, the top skin, the doubler and the rib, or separate out the parts and just dimple the top skin for the #8 screw. If so, how did you address the wing walk doubler? I had someone suggest to separate them, then drill an oversize hole for the dimple to sit in, in both the wing walk and the rib. Suggestions? Also, what did y'all use as .032 skin or scrap to test the fit of the mating of the two top skins? Thank you for any help you can give.
Van's Air Force
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Nutplates on Inboard Wing
- Thread starter jswareiv
- Start date
I countersunk the inboard top skins and dimpled the bottom inboard skins. With one exception. The aft most top inboard skin hole is dimpled.
I think this is (should be) what the construction manual describes to do.
propsync
Well Known Member
There seems to be confusion on this part.
If I am understanding what you are asking, you do not dimple any of those parts. The 4 inboard ribs (top), the doublers, and the skins are not dimpled at all, including where the nutplates are. You countersink the top skin only in those locations. The only dimple there should be is at the very trailing edge of the top skin and that is the center hole for the last nutplate.
See where I have circled in this pic, that is the only hole that is dimpled.
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This not correct.
A Van's Aircraft design standard is that nutplate attach rivets never get buried (making them difficult to replace if needed).
I prefer to do it after final assembly/riveting.
Machine countersink deep enough for a #8 screw dimple.
propsync
Well Known Member
Agree. I simply followed the order of the plans. After everything (skin) was riveted, that's when I countersunk the screw holes. It's basically one of the last steps of the entire section, (14-04 step 2).
This would be fine as long as the depth of the countersinking required doesn't create a knife edge on any of the layers.
propsync
Well Known Member
The directions seem clear that you should not countersink to normal depths, ie the head of the rivet can protrude slightly above the skin. Presumably this is ok because you will have wing-walk/safety-walk material on top.
It does knife edge layers and it is still fine.
RV's have been built this way for decades with no problems, and it is exactly how all the wings used during static testing were built.
I think you are talking about something different... the original question was regarding how to do the countersinks on the top of the root rib, for attachment of the root fairing.
Andrew M
Well Known Member
Experiance
True, buried nutplate rivets are a concern, very doable in this case as it's on the edge. I have had to deal with this issue maybe a dozen times in my 25 year career. I have decided to take that risk (minimal)than have deep skin countersinks. I think it looks bad.
The trick that goes with it is like this. Drop a countersunk rivet in the nutplate hole. The rivet will center itself, and has a dot to place the dividers that is center. Put some metal tape along side it, where the fairing will not cover. Use dividers to scribe an arc on the metal tape. Place the fairing in position. Use the dividers to put a "fix" on the hole center from any two spots on the arc that are about 90 degrees apart. This method is incredibly accurate, I prefer it so much to hole finders (strap duplicators) that I do not own any.
Between tape, dividers, and play-dough I can locate just about anything.
True, buried nutplate rivets are a concern, very doable in this case as it's on the edge. I have had to deal with this issue maybe a dozen times in my 25 year career. I have decided to take that risk (minimal)than have deep skin countersinks. I think it looks bad.
The trick that goes with it is like this. Drop a countersunk rivet in the nutplate hole. The rivet will center itself, and has a dot to place the dividers that is center. Put some metal tape along side it, where the fairing will not cover. Use dividers to scribe an arc on the metal tape. Place the fairing in position. Use the dividers to put a "fix" on the hole center from any two spots on the arc that are about 90 degrees apart. This method is incredibly accurate, I prefer it so much to hole finders (strap duplicators) that I do not own any.
Between tape, dividers, and play-dough I can locate just about anything.
