REFLECTOR: Aluminum Fittings

[Kurt Winker]

Steve is right. The hi vibration on 40's technology can make the smallest flaw a stressor that will fail eventually. Someone put an aluminum fitting on the brakes on my 235. Been there since before I bought it, and they painted it to look like steel. Just happened to fail with a plane load of kids on a Young Eagle flight... Interesting adventure!

There are other issues; the high heat increases galvanic action that causes corrosion between dissimilar metals. The variation in heat expansion/contraction also makes it hard to keep the fittings snug. 
My Dad taught me most of this, I can probably ask him the references he has from Sandia Labs, but the basic avoidance idea is sound. 

Change them out and be worry free. 

Kurt. 

Sent from my iPad

On Apr 18, 2013, at 20:15, Brian Michalk <michalk at awpi.com> wrote:

> I have two aluminum fittings on the turbo that I had to order steel replacements for.  I haven't swapped them out yet, but will do that this weekend.
> 
> I'm trying to find the information on why we do this.  I've been told to not use AL fittings on the engine, but I don't know why, and can't find the reference.
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