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Longerons bent...but I might have messed up

mattasmith12

Active Member
After 4.5 years stationed in Hawaii (I know...poor me), I have been doing my best to make progress on the RV-6. Winter is setting in here in Michigan, so the time is perfect to keep my tropically acclimated butt inside and focus on building.

So...after much fretting and reading the forums, I have succeeded in bending my longerons for the RV-6 fuselage. It really was A LOT less of a headache than I thought. I used the method where I applied some pre-load and whacked it with a dead blow hammer. That's a pretty effective method! In fact, I got a little carried away and over-bent...necessitating some course correction.

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I was able to tweak the contour to fit the cutout I had made from a section of plywood. Everything looked pretty acceptable. Unfortunately, I was disappointed to notice that a series of small, barely perceptible ridges were left in the longeron. These are only visible in certain light. But they can be felt slightly when running my hand over the longeron.

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Should I be particularly bothered by these? Do they have the potential to deform the skin? Should I build on?
 
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I don't see the photos

I don't see the photos. If they are Google they need to be in a shared album.
 
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I think it will be ok. It's not exactly a precise part, if it was they wouldnt be telling you to use a vice and hammer to make it.
 
Compound curve

The photos are visible. I just had a look at my longerons for comparison. I bent them a while ago so I don't remember the detail but it was quite fiddly, though I did not get any ridges, note also there needs to be a twist in the ends that attach to the firewall. My longerons appear to have gentler bends than what I can see in your photos, so I don't know if yours are still maybe over-bent. I did the bending with the fuselage jig already set up and marked out for the bulkhead locations and I recommend this if you haven't already done so.
What does the underside of the ridges look like? Are there any gouges from the vise jaws? That could be a concern for stress risers.
Replacement angle should not be too costly, but the shipping will be a hurdle if you cannot get locally. I think the ridges will not show on the outside through a couple of layers of skin.
 
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