Is it Safe? It's eating me up..

SteelMike · #1 08-27-2008, 11:38 AM

So I'm just finishing up my right elevator, and in doing so, I realized that I screwed something up on my left elevator. You see, I did the left elevator way out of sequence - almost the very first thing - and I'm older and wiser now (but not much!).

In riveting the spar together, I'm realizing that the rivets on the platenuts on the left elevator are facing the wrong way, such that the shop heads are on the platenuts side, not the spar side. I'm worried that those little platenuts aren't going to give the shop heads enough support. If it were any other part, I'd probably shrug and move on, but this is where the elevator is connected to the HS, you know! Kind of an important connection!

Can someone weigh in?
Thanks...

aparchment · #2 08-27-2008, 11:41 AM

I think pics would help further the discussion.

SteelMike · #3 08-27-2008, 11:45 AM

Well, probably, but the problem area is enclosed inside the elevator, so I can't take any pictures..

that's the other problem... it's so tough to correct! I'd have to drill out enough of the rivets holding the skin on - probably the vast majority on at least one side - to get at the platenuts...

Flying Scotsman · #4 08-27-2008, 12:06 PM

I'm confused here...shouldn't the shop heads *always* be on the platenut side?

Aren't the platenuts held on with 426 flush rivets? (I'm trying to think back to building the elevator, and I'm not at home to go look at it right now).

If a platenut is held on w/ 426's, then the part to which it is held is either dimpled or countersunk (and if dimpled, then we use a dimple die on the platenut, too).

cytoxin · #5 08-27-2008, 12:07 PM

doubtful it would matter. as long as no interference is encounterd it doesnt matter which way the rivet goes in. typically, and some will argue, but the shop head goes on the thicker material. YMMV

sprucemoose · #6 08-27-2008, 12:07 PM

Mike,

Is this what you're talking about?

If so, you are fine. I took a quick look at the preview plans (all I have handy) and it doesn't indicate which way those rivets are supposed to face. Furthermore, rivets which hold nutplates in place are not generally critical. You can hold nutplates in place with epoxy or dried bubble gum. The force of the jamb nut on the rod end bearing, against the elevator spar/ nut plate is the important point. The rivets just keep the nutplate from falling out while you screw the rod end in.

Flying Scotsman · #7 08-27-2008, 12:12 PM

I found some pics from the previous plane we built...I see what you're talking about now. They're held on with 470 rivets, so I don't think it makes any difference at all. The other posters are right. The rivets aren't structural on platenuts, they just hold it so you can screw in the bearings and use the jamb nut to hold everything in compression.

We just put the factory head (correction: on the platenut) for aesthetic reasons, but no reason it couldn't go the other way.

vmirv8bldr · #8 08-27-2008, 12:13 PM

Ok, so rivets on platenuts are generally there for two main reasons.

1. Hold the nutplate in place
2. Keep the nutplate from turning when you insert the screw or bolt.

After that, it depends on what's being mated. In most applications, something will be flush against the side opposite the nutplate, and the plans call for -426 type countersunk rivets.

So, if you installed the rivets backwards, the side that was to be flush, will obviously no longer be flush due to the shops heads protruding. As such.....you need to remove them and install correctly.

If nothing mounts flush to the surface, and you can get whatever fastener is required into the nutplate, and tightened, then you're probably ok.

As stated previously, pictures are helpful. If you can't visibly see the nutplates, take a picture of the structure and add a red line or arrow pointing out where they are so we know what nutplate you're referencing.

gasman · #9 08-27-2008, 12:25 PM

The rivets on a nutplate are only there to keep the nutplate in place, and to keep it from turning. The rivets add nothing to the nutplate after the bolt or screw is installed in the nutplate.

SteelMike · #10 08-27-2008, 12:38 PM

Sprucemoose's picture is exactly what I'm talking about. It's hard to explain, but the rivet directly above the screw/bearing is one of the ones I'm referring to - it's shop head is holding on the platenut to the other side of the spar. He's got his going the same way as I have mine.

I feel better, especially since the comment about the rivet's job is to hold the platnut in place and keep it from twisting, but that the screw/jambnut is the load bearing part.

I feel much better...