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Kent Ashton

Varieze wing fittings

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I came across this video about replacing Varieze wing attach fittings.    He calls it an EZ and it appears to be an unfinished (unskinned) piece of wing but it will give you an idea of what would be involved.  Not really sure it is practical to do it with four fittings on a real Varieze. 

https://youtu.be/FEftp5OT1-A

 

Edited by Kent Ashton

-Kent
Cozy IV N13AM-750 hrs, Long-EZ-85 hrs and sold

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Here's a Rutan discussion of the problem.   I don't think they ever developed an easy way to repair them and it is hard to detect but I'm not a Varieze guy.   http://v2.ez.org/corrosion.htm


-Kent
Cozy IV N13AM-750 hrs, Long-EZ-85 hrs and sold

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3 hours ago, Ratdog said:

 if you buy an uncompleted Varieze and you still have good access to these plates is there a recommended fix is to make them more durable ?  is it just corrosion or is the design a little flawed . 

It sounds like a pretty dicey procedure with a lot of potential dead ends.  

The only "fix" for a wing attach fitting corrosion issue is to completely disassemble and remove the metal parts, ensure that the composite spar is sound and wasn't damaged in the process of the original metal fitting installation, and then fabricate new fittings, protect them with alodining and appropriate coatings and then re-install everything with wet hardware. If you don't know what ALL of that means and how to do it, you're not in any position to do the work.

As I've stated numerous times before, I believe that it all could be done in about 40 - 80 hours of work, assuming that the underlying composite spar is in good shape.

As you surmise, there are many things that could bite you - the composite spar could be damaged, you might damage something in the removal of the corroded metal, or you might have trouble getting all the re-fabricated pieces to align and fit together correctly upon re-assembly. Paying someone $4k - $8k to do this work, with no guarantee of success, seems like a risky path to me.

VE's change hands fairly regularly, and they don't fall out of the sky regularly, but there HAVE been at least 4 known instances, in around 2K Variezes, of corroded wing attach fittings. Who knows how many are corroded and haven't been discovered? Nobody. I most certainly would never buy one that had any visible corrosion anywhere on the wing attach fittings.

See the picture below for a corroded fitting example - the visible portion, near the hand, is fairly decent looking - you wouldn't necessarily expect that the non-visible portion has severe interlaminar corrosion that has removed over 1/3 of the thickness of the material and damaged the rest.

IMG_0117.jpg

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5 hours ago, Ratdog said:

How can you tell if a part has been alodine treated by lookin at it . ?

Usually, they'll be yellowish, but that's no guarantee, and it's no guarantee that it's not if it isn't yellowish.

But since 99% of the VE's out there were built with non-alodined and protected wing attach fittings, it's a pretty good bet that any VE you look at will not have protected fittings.

Based on my experience and the # of corroded wing attach fittings we know about in the population of ~2K - 4K VE's that have flown, I'd estimate that somewhere around 0.1% - 1% of VE's have corroded wing attach fittings that would compromise strength. Total guess, but a mildly educated one.

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