R

rv8_builder

Active Member
I am new to airplane building and started the horizontal stabilizer with great enthusiasm this weekend.

That is until I made the first mistake on HS 404 ? I overlooked the part in the manual that states ?make a left hand and right hand? when cutting out the nose ribs! :mad:

I drilled holes in the corner of each cutout to make a radius in that area. Only after drilling the holes I realized that I had made two left hand ribs. Fortunately I could partially correct my mistake by drilling two new holes offset the other way, before cutting out the corners.

I now have an additional hole in the right hand rib.

Can I use this rib or do I need to replace it :confused:

hs404.jpg
 
That looks like a prime spot for a possible crack (very close to the edge and bend). I'd either trim the rib some more or even better, order a new one. They are not expensive and you'd have the piece of mind.
 
Or just extend the cutaway to that hole. The flange against the front HS spar will be slightly shorter than it would have been per plans, but as long as you have have the same # of fasteners and you satisfy minimum edge distance & pitch requirements, I don't think it would be an issue (keep in mind this is "armchair engineering" at work here). Call Van's if you're unsure.

I'm not familiar enough with the latest kits to know if the in-spar rib (the one that goes between front & rear spars) has a pre-punched flange there. If it does, then you might be looking at replacing that nose rib. If it doesn't, then you should be ok.
 
Another option would be to cut off the flange with the hole in the wrong place and make a new angle flange from some of the off-cut material supplied with the kit. This can then be riveted to the web of the rib in the correct place. Use the same rivet size, spacing and edge distances etc as for the attachment to the spar. Alternatively for not much more than the price of a cup of coffee you could order a new rib from the factory and have it delivered within a few days! The joys of home built aircraft ;)
Jim Sharkey
 
No Worries

Well being in S. Africa it would cost alot more than a cup of coffee. So there are lots of easy options so don't worry.

The easiest would be to take a piece of 0.032 angle stiffner (same thickness as rib), like the rudder stiffener and cut a piece to match your flange. Simply place inside (radius to radius), drill and rivet to the rib, essentially creating a doubler.

Of course you could also fill the hole with epoxy or JB weld and press on. Your mistake is not really a structural concern here.

You are in good company. My first mistake, seemed like a catastrophy. They always do. But as you go along you will learn that it usually not a big deal and very seldom unrepairable. :)
 
jsharkey said:
Another option would be to cut off the flange with the hole in the wrong place and make a new angle flange from some of the off-cut material supplied with the kit.
Click to expand...
If I didn't want to wait for a new part, that is exactly what I would do. Further, I would pick up and fill the existing tooling hole with an AD6 rivet, but that is not strictly necessary.

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Wow! - Thank you for all the great advice, I sure am in good company here :)

I will find out from Vans today what the cost / lead time of a new rib will be, and then decide if I am going to replace or repair.

Thank you all for a great forum :D
 
hole

I would do what Rick says. That would be easiest, cost effective, save time for waiting on part and structurally have no change. Out of curiosity to the group, would it hurt to put a round head 3/32 rivet to fill the hole (not the tooling hole but the accident hole)?

If that's the worse mistake you make "RV-8 builder", that will be amazing. Little things like this happen, and if they are fixed properly, it's absolutely no big deal.
 
Rick6a said:
If I didn't want to wait for a new part, that is exactly what I would do. Further, I would pick up and fill the existing tooling hole with an AD6 rivet, but that is not strictly necessary.

eesn4.png
wwlx1.png
Click to expand...

The only thing I'd add here is to rivet the angle opposite the side the flange is on (i.e. rivet to the bottom of the rib as shown in the photo). The only reason being that I think the edge distance through that particular flange pretty minimal so if you rivet on the other side of the rib you don't reduce the edge distance by the thickness of the angle.

What do you think? Just a thought.
 
Does edge distance to the bend count??????

I thought edge distance requirements were only to the true/cut edge of the material?????
 
grantcarruthers said:
Does edge distance to the bend count??????

I thought edge distance requirements were only to the true/cut edge of the material?????
Click to expand...


I think I read in my rv-8 fuse instructions, in the gearbox section, that you can go closer to the bend but its obviously hard to set a rivet when you get that close to a bend.
 
I was actually just remembering how it was on my -7, and it's probably similar on the -8. Because of how you drill the hole, it was easy to be off a little and come close to the edge so I thought reducing that (assuming it didn't matter how you made the repair) probably wouldn't help things. Nothing to do with the bend :)

Anyhow, it was just something that occured to me when I saw the picture. I'm sure it'll work fine either way.
 
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