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Wing Ribs

Capflyer

Well Known Member
I am working on a secondhand RV4 kit where the original builder built the spars for a HRII clipped wing mating to a standard RV4 fuselage. I am going the full HRII route. The measurements for the ribs begin at 17" from the root end. The OB had the holes for the support angles measured from the 15" mark (thinner fuselage on the RV4). When I measure for the rear ribs from the 17" mark a few of the inboard ribs do not line up to fit with the support angle bolt holes already in the spar. The stations on the HRII plans seem to be pretty precise down to 32nds. None of the rivet holes for the ribs have been drilled into the spar yet.

My question: Is it any problem to move a few of the ribs so they line up with the existing rib support angle bolt holes?
 
Been watching this since yesterday and no one has chimed in. Tough question to answer from a description. Sounds like you're trying to make HRII wings from a spar already drilled for an RV4. You're probably on your own here. The only generic guidelines I can give would be:

Don't violate the rib density or the maximum spacing for the configuration you're trying to ultimately achieve.

Do not violate minimum fastener spacing (rivets and/or bolts) anywhere. That could be tough anywhere and maybe impossible in the wing walk area.

Lots of future head scratching in your future. Much easier to start from scratch if changing configuration regardless of the quality of the previous workmanship. Best of luck. Will be watching this.
 
I, too am trying to picture it.
How far will the ribs shift?
If you are only moving them a wee bit, say the width of a flange, you could swap “L” and “R” flanged ribs to keep the center of the rib close to the original position.
 
Sorry for my confusing question but I got an answer from John Harmon on this late yesterday. He said if the ribs would be close to the original position it would be fine, just not to drill any new holes. Fortunately only a few of the ribs are off and by drilling out the rivets at two stations I can have all the ribs within a 1/4" of their prescribed locations. Fortunately the end ribs line up perfectly already, those would be the critical ones.
 
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