boom3

boom3

Well Known Member
My wing kit is a week or so away :D so I have been working on my empennage fiberglass tips. I have predrilled the tips to 3/32 and am getting ready to drill them to 1/8, then dimple the skins and machine countersink the tips. My question is can I dimple the double skin where the elevator skin overlaps the counterweight skin? I think I have too but it seems kind of weird. Maybe I should have done it earlier? What do you think? The holes in question are the ones in the center without clekos.

Thanks!

twoskins.jpg
 
Jeff,
It shouldn't be a issue at all to dimple two skins. I had to do it recently on the wings on the rear spar/rib flange. Worked great. Other option is to countersink the holes for the shallow 120 degree rivets that go there (CS4-3's or something like that). Then you don't have to worry about dimpling, and you don't have to countersinking the fiberglass.
 
As the education part of your project, may I suggest that you use a couple of pieces of .020 thick (or something close) scrap material and try it your self and see how it works.

This is not at all meant as a flame because you asked the question... just pointing out that in this age of the internet, it seems many of us builders don't do as much thinking for themselves as they used too.

It is my opinion that a lot of the info and advice passed along in these online forums is bad advice. As builders we need to think for our selves and "test" any advice provided by others (also not meant as a flame towards the guys that took the time to answer your question).

In answering your question...I agree with the other guys, that it will dimple just fine. If the two pieces of material were .032 thick it would not dimple as well but would still be acceptable. (but don't take my word for it ;) )
 
Double dimpling

......oh, and by the way, my rivets set better in the dimple after I dimpled the skins together. The left elevator was not done that way and the rivets sit in the dimple slightly "proud". When I dimpled the 2 skins together on the right side it made the rivet sit perfect to the skin.
 
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