Tear in Dimple hole - what to do?

Hey guys,

While dimpling the rear spar on the right elevator for my RV10 with my pneumatic squeezer, I justtt missed one of the holes and tore a little flap of material out of the side of the dimple.

Here's the inside of the dimple:

And the outside:

You can see where the male end of the dimpler caught the edge of the hole and tore it a little. Dimpling in the proper hole pushed the little flap back down, resulting in that tiny tear on either side.

Here's one final picture with the location of the hole: It?s right where my finger?s pointing.

What do you guys recommend I do? Will this require a replacement piece? I?ve read that you can stop drill the end of these cracks to prevent them from spreading - I just don?t know if this is small enough that it?ll just get clamped down by the rivet. I guess alternatively I might cleco everything together again, drill a hole on either side and add an extra rivet?

Thanks in advance for your help. I sent the same note to Van's builder support and will report back what they have to say.

Well cracks don't just get clamped down and disappear out of sight. Especially if a crack is on the tension flange of a beam, it will be encouraged to spread.
If it were me, and if,
Then I would try to clean the hole up round to .199" diameter and install a NAS20426A-6 (soft #6) rivet through the spar only, using the existing dimple and shave the head flush. (The picture looked like a 6 would clean it up... I could be wrong).
Then double flush the pilot hole in the skin and shaving both sides flush.
Then add a rivet midspaced on both sides

Probably sounds overkill to some people but that is just what I would do.

Van's may have something completely different to say about it.

I'd say Andrew has a good approach. At a minimum, you need to drill or file out the hole enough to remove the cracks/tears. You could perhaps flatten the dimple and abandon the skin hole (flatten that dimple as well if needed). Plan on filling it when you finish the exterior. You will need to add a rivet on each side to replace the lost strength.

I bet that is only a $15 piece plus $5 shipping (since I had to buy the same piece for a -14, when I did something stupid), so just buy a new one that is what I do.

You are building a -10, which is at least $150K project. $20-25 for peace of mind.

I am not sure how many parts I have purchased from Vans. Mostly from not reading the plans closely enough or doing something stupid with a band saw or dremel. I used to post my mistakes, then I just decided to buy the part and move on.

The part will get to you in 3-5 business days.

Well, the problem is that with the elevator, you need to match-drill and cleco every hole in the spar from the middle out as you go. Now that I've already dimpled every piece, I won't be able to order a new piece, reassemble everything and get anything close to precision when match drilling, since the skin dimples won't let the pieces lie flush. (I'm totally with you and have done this for a different piece in the horizontal stabilizer with a little bend.

At this point, I'm thinking that I'll probably just flatten the holes out, drill it out and add a rivet on either side. Really good advice from everyone - I'm just trying to figure out how to make it work without having to replace the ENTIRE elevator. (I'm happy to do that too, but it probably makes sense to try to salvage this, and only build an entirely new elevator down the road if I have to.

Every extra hole in a spar cap weakens it a bit. I'd run any plan past Vans engineering.

I agree with stockmanreef. I bought new parts when I screwed up. I sleep so much better....even if Vans signed off on my proposed repair method.

Stockmanreef said:

I bet that is only a $15 piece plus $5 shipping (since I had to buy the same piece for a -14, when I did something stupid), so just buy a new one that is what I do.

You are building a -10, which is at least $150K project. $20-25 for peace of mind.

I am not sure how many parts I have purchased from Vans. Mostly from not reading the plans closely enough or doing something stupid with a band saw or dremel. I used to post my mistakes, then I just decided to buy the part and move on.

The part will get to you in 3-5 business days.

Click to expand...

Check with Van's but they have told me in the past that match-drilling in certain spots is not quite as critical as that. Just run it by them and see what they say.

Stockmanreef said:

I bet that is only a $15 piece plus $5 shipping (since I had to buy the same piece for a -14, when I did something stupid), so just buy a new one that is what I do.

Click to expand...

Yeah, I'm thinking that's what I'll do. When you bought the new rear spar, did you just drill all the holes out to their proper sizes, dimple and rivet without matching everything up? Or if you hadn't dimpled yet I guess you could just cleco everything back together and do a proper job of match drilling.

If you have already dimpled the skin, I would just drill the spar to final size and dimple it. These pre-punched kits are extreamly accurate.

Like most others, I would replace the part; helps me sleep better at night for realitavly little money.

what is the point of putting an oops rivet in the hole in the spar? If it is on the tension side there won't be any increase in strength. Isn't the objective just to ensure the hole is clean with no cracks? Once you have done that what does filling in the hole accomplish?

sblack said:

what is the point of putting an oops rivet in the hole in the spar? If it is on the tension side there won't be any increase in strength. Isn't the objective just to ensure the hole is clean with no cracks? Once you have done that what does filling in the hole accomplish?

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Filling an open hole reduces the stress concentration at that location. Plugging a hole with a rivet will not allow the hole to deform in extreme loading situations and thus will be less likely to fatigue. Scott, I'm sure it would be fine to leave it open, but that's just what I would do with my airplane if I decided to fix it.

By the way, I agree Sam if you decide to replace that spar. It would be easy. I would go ahead and cleco the dimpled skin to the holes so that everything is match drilled. I know the prepunched holes are accurate, but it can be annoying when rivets don't want to seat all the way in the dimple because holes don't want to align 100%.

Oh yeah, and I don't like hearing about dimples being flattened. It reminds me of bending a paperclip a few times...

Sam, did you ever hear back from Van's?

clutch22 said:

Sam, did you ever hear back from Van's?

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Hey guys,

I gave Van's a call this morning; the engineer at builder support recommended that I file the hole out to the edge of the crack, make a little doubler that captured this dimple and a rivet on either side, dab a little proseal on the crack before squashing it then just proceed. That should stop any crack propagation.

Haha, as has happened every time I've called builder support, the tone was very much "This happens ALL the time, and there's no way you can just trash a part every time you run into something like this." If it were earlier in the process I'd probably have just ordered a new one right away, as I said, but it's really good hearing this from the Van's.

So! That's the plan. I made my doubler this morning, filed the hole out to the end of the little cracked piece, and everything is nice and rounded now. No crack, and the doubler should provide the extra metal for strength.

Thanks all for your advice!

RV7AJeremy said:

If you have already dimpled the skin, I would just drill the spar to final size and dimple it. These pre-punched kits are extreamly accurate.

Like most others, I would replace the part; helps me sleep better at night for realitavly little money.

Click to expand...

Plus 1 for this.

2 rivets

you can clean up the hole and put a rivet on both sides of it as well if you have the clearances.