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New build - bent aluminum question

N14KR

Active Member
Hi All,
I'm a new builder staring a -14A. Working on Vertical Stabilizer (after having done the SportAir class and a few practice kits) and really enjoying it.
Today I was working on the top tip rib, part VS-706, on the step where I need to radius the corners at the Tip Rib flange to ensure a good fit when skins are installed.

While making the radius on the scotch-brite wheel, I accidentally caught it wrong and it bounced off of the wheel and slightly bent the forward tip of the rib.
Picture below:

VS-706-e1525532731808.jpg


It will install fine, but wondering if the part should be replaced? I of course want a "near-perfect" plane, but trying to maintain pragmatism and not be overzealous during the build. The light during the pic makes it worse than it is.

Also - why were the Ribs not sent in blue vinyl? I am pretty sure no clear vinyl on them. Just seems strange considering nearly everything else was sent still covered.

Thanks for your thoughts.
 
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Close call maybe but I would replace that one. I replaced the same part because I over aggressively eased the edges.

It’s the kind of thing that will bug you if you leave as is. Not that there aren’t a few of those still installed in my build. Some non-alclad parts come sans vinyl. Just did my roll bar and it was the same way as have been many parts along the way.
 
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Rib

Cheap part, cheap shipping. Replace and sleep.
You obviously know why it caught.
Tip. Swap the wheel on the opposite end for a buffing disk. That way, if your part catches on the opposite wheel you won't have to order a new part. Don't ask how I know or what that lesson cost! :eek:
 
If you're gonna order a new one, you might as well at least practice re-shaping that piece. I wouldn't be surprised if you could massage it back to near-perfect.

Chris
 
The pieces that do not have blue vinyl are I believe are usually not ALCLAD aluminum.

section 5.1 says

All non-alclad aluminum parts such as 6061-T6 must be primed. Control System Pushrods must be primed both inside and out. (Do
not prime inside of fuel or brake lines.)
 
Also - why were the Ribs not sent in blue vinyl? I am pretty sure no clear vinyl on them. Just seems strange considering nearly everything else was sent still covered.

Thanks for your thoughts.

Bent parts, like these, are made from 6061. Initially in a soft state (T0) to yield in the forming process, then they are heat treated for strength to T6 state.

The blue vinyl is applied at vans prior to the CNC punch, cutting, rolling processes to protect the finish ( and thin layer of pure aluminum) of the 2024 parts.

Funny Vans recommends a general priming of 6061 parts as DoD testing shows just about any primer is ok for them, 2024 (with it's alloy) has very specific needs for corrosion protection. Do what Vans recommends, though.
 
Thanks everyone for the input. Agree with all the sentiments, I?ll just replace and not worry about it. I was smart enough to replace the other wheel with a buffing disc, but not clever enough to avoid this mistake. Lesson learned.

I was pretty sure those parts were non-alcad, but this pretty much confirms it also.
 
With experience, you will reform that part, inspect, use it or not and make your decision.
If it where me, I would use my back rivet plate or anvil and try to work the web back into shape with a flush set. If the original damage didn’t stretch the skin too much, it might just bend right back. Since it bent at the break in the flange, check that area for any cracks. If it doesn’t work out, order another part. It won’t take long to try and you gain some good experience.
 
OK, I am not an engineer or any such----but I would like to get my $.02 in here.

There are two reasons to replace a part IMHO---one is for structural reasons due to potential failure. The other is to make yourself feel good.

Think about what the design purpose of this part is--------it gives shape to the stab skin. It could probably work fine cut into pieces at each side notch, as long as there are a couple rivets on either side of the notches.

If there is a dent or other defect in the rib, will it interfere with the purpose of the part and will it compromise the structure?

You said that it will install fine...........

As long as there is no cracking at the bottom of the notches, I would probably build on. Trying to do a lot of rework to flatten the part and remove the bent area could very well cause more damage than just leaving it alone.

Best bet?? Call Vans Monday and get the official word.
 
OK, I am not an engineer or any such----but I would like to get my $.02 in here.

There are two reasons to replace a part IMHO---one is for structural reasons due to potential failure. The other is to make yourself feel good.

Think about what the design purpose of this part is--------it gives shape to the stab skin. It could probably work fine cut into pieces at each side notch, as long as there are a couple rivets on either side of the notches.

If there is a dent or other defect in the rib, will it interfere with the purpose of the part and will it compromise the structure?

You said that it will install fine...........

As long as there is no cracking at the bottom of the notches, I would probably build on. Trying to do a lot of rework to flatten the part and remove the bent area could very well cause more damage than just leaving it alone.

Best bet?? Call Vans Monday and get the official word.

Most of that. Thanks Mike.
Personally, I would have expelled only one four letter word, then just picked it up off the floor and continued executing with the "new", "untested", "experimental" part, that I would continue to "adjust" to meet my needs. If need be, that whole part is easily made from scratch in the shop in less time than waiting for the UPS guy to make his way down the street. I really feel for the people at Vans that answer the phones. Like Mike said, that part could even be sliced up into multiple pieces, if you're comfortable with that, and still be made to be serviceable.

"Build on."
 
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$8.45 plus shipping according to the parts list.

It probably won't be the last piece you repurchase. And you will sleep better at night.
 
If your goal is to assemble an aircraft kit, buy the new part. If your goal is to learn to build an airplane, develop the skills to do so.
This is a really minor ding that should easily work out, if it needs to be worked out at all. ( I don?t accept dinged webbing but that?s just me).
If fixing this yourself risks keeping you up at night, by all means buy a new part. However, if you don?t have the skills to know what an airworthy part is, I would suggest you develop them. You may need them in the future unless you intend to have someone else inspect your airplane, part by part, assembly by assembly as you build (not a bad idea until you learn). You need to know what is ?ok? and what is not. This is part of the learning process.
This isn?t about money or shipping time. It?s about how you want to proceed and what your end goal is. That decision is up to you and there isn?t a right or wrong answer except it needs to be a sound part. How that gets done, fix, repair, fabricate new yourself, or simply replace the part, or not, is up to you, but don?t just run out and buy a new part unless your goal is just to move on. Many experienced builders do this for times sake when something is really messed up, but this part can probably be fixed in a few minutes just judging off of the one picture.
Back in the day, if you completed a Van?s kit, you developed an impressive set of skills. Today it seems more about fancy interiors, paint, and avionics than it does about sheet metal, and that is ok too. We wouldn?t have so many really nice machines flying if the kits didn?t assemble as well as they do today.
Good luck on your path and have fun with your build.
 
I agree that if you are uncomfortable making the decision you can just replace the part. You won't learn much that way though and you still have a long way to go.

There are other options as some have listed. A good one is to take it to your local EAA chapter to have a tech counselor look at it.

They may say...

-Good to go.

-Here's how to fix it.
..Easy, just clean up the separation between the flanges, no cracks.
..Harder, add a doubler.

-Replace it.
..Here's how to make a new one.
..Buy a new one.

A good option for future goofs as well. And there are more in your future!

Good luck.
 
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Good to be cautious, but how is that rib loaded when in use?

It mainly serves in compression and I don't think much stretch or bending takes place in the vicinity of the deformation.

I'd lightly "massage" it back flat with a small wood mallet, or soft faced hammer.

Pay a little attention to polish the inside of the radius in case they were stretched more than is "comfortable" for the metal.

Onward and upward.
 
Thank you all

I'm humbled by all the thoughtful responses. I kept inspecting the part and came to the realization that the bend was very slight when it happened. And based on what it's being used for, the lack of any issue with it fitting in between the skin as designed, and the nearly negligible effort to massage the web to nearly new, I'm going to use the part and move on. As folks mentioned, so far the hardest part to learn is not the actual assembly, but maintaining a high standard but realizing that is not perfection.
Thanks again.
 
Rich,

Welcome to my world! I am an aircraft structural engineer (stress analysis) and I constantly struggle with this type of decision whenever I accidently add a new design feature to a part. It's my opinion (backed by my experience but not by any numbers at all) that the -14 is very solidly built with enough safety margin to accept some defects.

However, I almost always order new parts if for the sole reason that I sleep better knowing that "new feature" isn't there anymore. Especially so if the part is cheap (which this one is - I know because I messed up some holes on this very part) and the shipping time is short (2 days for me).
 
fix it and inspect for cracks

With experience, you will reform that part, inspect, use it or not and make your decision.
If it where me, I would use my back rivet plate or anvil and try to work the web back into shape with a flush set. If the original damage didn?t stretch the skin too much, it might just bend right back. Since it bent at the break in the flange, check that area for any cracks. If it doesn?t work out, order another part. It won?t take long to try and you gain some good experience.

This is what I would do. GENTLY with flush set, or wood block and mallet.
 
Updated pic

Took barely no massaging to make it seem new. Attached a pic, but had already primed

3A2DD1B6-E2F5-4972-87E4-AADE2295D4E1.jpeg


Sent for a new one anyway, but pretty happy with this.
 
Steps in Learning

Nice repair -and I also wouldn?t hesitate to use it. Mount the new one on the wall as a trophy.

Here?s the thing - the reason that we start building with simple things like tail feathers is to develop our building skills before we get to expensive, large assemblies. And a very important part of those building skills is repairing damage caused by mistakes or accidents. When you get to those big, expensive pieces, you need to be able to know how to salvage work that might have gone wrong. As an extreme example, what will you do if your wings are essentially finished, and you slip up installing a tip? Will you throw away the wing and start over? Or remove lots of skin ( introducing enlarged rivet holes or other damage) in order to replace a tip rib or skin panel?

If someone slips with a drill on the final panel of a 737 wing, Boeing doesn?t scrap the wing, they come up with a fix. And you need to develop - and practice -the ability to do the repairs as well. Yes, sometimes parts are beyond salvage, and in learning repair techniques, you will learn where the limits are. Learning to determine when parts are salvageable, and when they aren?t is far more important than buying two (or three) of anything.

Call this a successful learning experience that will prepare you to evaluate future mistakes and choose the right path in each case.
 
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