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  #11  
Old 03-22-2017, 07:50 PM
Ralph Inkster Ralph Inkster is offline
 
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Yep, guess it's up to who you get on the tech line.
I like the idea of Tinnerman washers too.
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  #12  
Old 03-23-2017, 05:34 AM
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Mark Dickens Mark Dickens is offline
 
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Perhaps the way to look at it is that those fairings are certainly aerodynamic if not truly structural. I've heard a story from a reliable source that flying the plane without them installed makes the plane almost uncontrollable. Don't ask me why this happened...wasn't me. My aft-most hole on the bottom didn't match well and I had to elongate the hole in the fairing and use stainless tinnerman washers to finish the job. Stainless and aluminum will corrode, so prime the inner surface of the washers.
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  #13  
Old 03-23-2017, 06:44 AM
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bret bret is offline
 
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Not an engineer nor did I stay at a Holiday Inn Express last night.....but, I can see this adding to + G strength with the bottom skin all connected in tension
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  #14  
Old 03-23-2017, 07:10 AM
6 Gun 6 Gun is offline
 
Join Date: Jun 2005
Posts: 846
Exclamation screws

Yep I went to search and found lots of info on this subject as I had a ? a few years ago on this same subject.The RV3,4,6 were load tested with out screws in place and 7,8,9 with screws in place so yes they are part of the wing!
Bob
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  #15  
Old 03-23-2017, 08:53 AM
BillL BillL is offline
 
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Quote:
Originally Posted by bret View Post
Not an engineer nor did I stay at a Holiday Inn Express last night.....but, I can see this adding to + G strength with the bottom skin all connected in tension
Quote:
Originally Posted by 6 Gun View Post
Yep I went to search and found lots of info on this subject as I had a ? a few years ago on this same subject.The RV3,4,6 were load tested with out screws in place and 7,8,9 with screws in place so yes they are part of the wing!
Bob
Odd that Gus would say not structural. Vans will compromise on cosmetics, but not safety. Maybe he assumed that they would still share the loads even if elongated, at least in this direction. He has a lot of experience and surely this discussion has been thrashed with engineering.

Anyway - although they carry some load, the pitch/spacing is not adequate for full skin load transfer, so Scott could just add screws between existing ones and move on. This addresses the strength and offset issue. OTOH - this shifts loads to the skin, and changes the load balance of the structure. Jon Jay said his screws loosened periodically for a while then stopped. So, clearly they do carry see some load, but how much they carry is open for analysis. Back to Vans.
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  #16  
Old 03-23-2017, 10:40 AM
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JonJay JonJay is offline
 
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Quote:
Originally Posted by BillL View Post
. Jon Jay said his screws loosened periodically for a while then stopped. So, clearly they do carry see some load, but how much they carry is open for analysis. Back to Vans.
Another CI or two since that report and they are still tight. There could have been other factors at play. However, the rear spar bolt discussions and confirmation from Scott McD, that joint can move. If it can move, that belly skin must be taking some load at some point. I would suspect it isn't going to be cause or a factor in a wing failure. As you point out, there are too few screws to put that sheet to much work.
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  #17  
Old 03-23-2017, 11:03 AM
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az_gila az_gila is offline
 
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Quote:
Originally Posted by Mark Dickens View Post
....
Stainless and aluminum will corrode, so prime the inner surface of the washers.
Or simply take those screws and washers out when the plane is painted.
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  #18  
Old 03-23-2017, 11:40 AM
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Janekom Janekom is offline
 
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Default I thought they are strutural

A couple of years back I also had an RV7 in my shop without those screws. Asked Vans and the reply was: Do not attempt to fly that aeroplane as it is structural. Cannot remember who it was but I find it interesting how opinions differ
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  #19  
Old 04-02-2017, 02:21 PM
rv8builder2014 rv8builder2014 is offline
 
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Default Screw alignment issue

Did you go back and check the angle of incidence on the wing as well as check the wing for forward and aft sweep after you ran into this problem? That is where I would start. Wing twist shouldn't be an issue with this particular problem.
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  #20  
Old 05-14-2018, 01:11 PM
SgtZim SgtZim is offline
 
Join Date: May 2015
Location: Crittenden, ky
Posts: 186
Default wondering about this too

I know this is an older post, but I'm now doing my fairings and I just match drilled those holes between the fuselage skin and wing.

My issue/question is about the fit of the overlapping skins. my fuselage skin hangs about 1/8" lower than the wing bottom, and clecoing the skins together of course causes major rippling because of the curved surface. I'm thinking about adding a filler strip between the skins just to make a clean joint, but if it is indeed structural - that would not be the best solution.

Also, if it is structural - the whole method of drilling those holes is very poor: You pre-mark lines along the wing skin and then you are supposed to take a stab at finding those holes in the wing by measuring off of those lines and back 3". Far from a good match drill. I had just enough room to squeeze in a hole duplicator, and made good matching holes, but the geometry of the two skins makes pretty bad ripples. Kind of a tradeoff between structure and aerodynamics for me anyway.

I sent my question in to Van's this am, I'll update when I get their comments.

picture of my wing/fuselage joint.

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