"Drop" dimple in HS-405 rib

[tegwilym]

Hello builders,
First post here, and of course I'll start out with a question. Might be silly, paranoid or simply the common Van's "build on!" suggestion.

I'm working on an RV-7A first of all. I've gotten past the part where you cut the flanges for the HS-405 rib to fit around the spars.

When I looked at the other end of the rib, I noticed a couple dimples on the inside that showed through to the other side. It looks like something was dropped on the rib. I can probably blame myself, but I don't remember doing that. Anyway, there it is. So I'm wondering, is this one of those "replace or just move on and be careful" type things?

See here -
http://www.mykitlog.com/users/displa...g=171224&row=2

Thanks,

Tom
Renton, WA

[Smilin' Jack]

I believe you'll call Van's and they will say build on.
Smilin' Jack

[Low Pass]

To answer this question for yourself answer these questions:

1. How will the part fail as a result of the damage I inflicted? Crack, buckle, etc.

2. Will the damage I created cause the part to fail? Can you debur/buff, straighten, leave it alone. These ribs are fairly malleable and not relatively susceptible to cracking. Unlike a deep gouge in a spar or longeron, or bent to he point you see disruption in the surface of the part. Could the rib buckle from this ding? You have better odds of an asteroid hitting the earth. Can it crack? Very minimal added risk of cracking - the ding is too shallow and not disruptive.

3. What happens if the part I damaged fails as I describe above? Do I die, plane has another rattle, nothing. Rib buckles - if that happens, you have much bigger problems (like the 10 g pullout you just sustained or the tree you just ran into). Rib cracks - it'll run to the edge and you'd probably never know.

4. Does it affect the appearance? If you ding an exterior skin, you plan to polish, and you cannot work the ding out, then replace.

5. Peace of mind? Let it sit a while and think about it after you cool off.

What you show is a simple learning point. Be more careful and don't drop tools on your plane! As for integrity, what you show is pretty low risk. I wouldn't do anything.

Followup question - rereading your post, it sounds like you don't know what happened. This concerns me more than the damage. How did it happen? Someone monkeying around with your project when you're not around?

[Mike S]

Originally Posted by tegwilym

Hello builders,
First post here, and of course I'll start out with a question.

Thanks,
Tom
Renton, WA

Tom, welcome to VAF

Gotta agree with above posts, these just do not look like a problem.

Good to have you aboard.

[Daniel S.]

Take your pneumatic squeezer (or alike) with two flat sets & squeeze it flat & move on if there are no cracks. looks like you dropped a tungsten bucking bar on it. I've done this a couple times... my one fuel tank has a nice "outtie"

[tegwilym]

Thank for all the ideas and comments. Very helpful to an airplane building newbie! I've built plenty of model planes, and a lot of woodworking, but metal is new to me. I'm learning a lot.

I like the idea of the "flat" pneumatic squeeze, that seems like a good work around. Seems that most think it's not a big deal. I do see other little dings here and there over the process (and of course flying) later on.

As for the "someone messing with the stuff" that was posted above, there isn't anyone else in my basement that I cold blame other than myself. I probably did just drop something on it and didn't know it until I backed off from the end I was looking at and saw the whole thing.

Anyway, I think I'll try to flatten it gently and move on while I think about my mistake and be more careful.

Thanks, I'll have PLENTY more questions coming soon.

(how did we ever build things like this before the internet?)

Tom

[deek]

Originally Posted by tegwilym

how did we ever build things like this before the internet?

Having built the 12th LongEZ to fly (completed in 1983) I ask myself the same question all the time

[wirejock]

Hey Tom.
Welcome.
Is it possible, this is HS404?
I don't recall trimming HS405.

Here's another option, but subject to VAF Experts opinion.

How about drilling a relief hole in the middle of the dent then flattening the remaining deformity?
I wouldn't know how big or if this option would impact the strength. Just a thought.
The part is pretty cheap if you want to replace it.
I've damaged a few much worse.
In fact watch out when you relieve R710 Horn Brace on the rudder. Cut less than needed and check the fit.
Don't ask me how I know!

[tegwilym]

Ah, right. It's the HS404 - the nose rib. I'm learning the part numbers pretty well from staring at them a lot!
The dimples aren't bad, maybe I'll try flattening with the pneumatic squeezer and see what they look like. I'll probably just replace the part out of sheer paranoia anyway. :-)

Currently, I'm carefully looking at how to drill the holes through the 405/404 and have them line up. Have a good idea, just staring at it a lot before drilling.
Tom

Originally Posted by wirejock

Hey Tom.
Welcome.
Is it possible, this is HS404?
I don't recall trimming HS405.

Here's another option, but subject to VAF Experts opinion.

How about drilling a relief hole in the middle of the dent then flattening the remaining deformity?

[wirejock]

Here's an important step. There are two holes either side on the spar you drill later. HS-708 to the spar. Look for "except the..." in the manual under "Drilling the HS". Others have drilled the spar holes here and had issues with hole location later. The holes are shown on the plan but there are no holes in the spar. They get drilled later in the assembly of the skeleton parts.

If memory serves, the measurements on the plans were perfect. Measure 50 times and drill them once.. Set the marks with a good punch and drill them smaller than the #40 in the book. The smaller bit doesn't wander as easiely. I think I messed one by a 1/32" or so because my bit wandered. It didn't effect anything. Mark the parts so they go back to the match drilled locations.