Sams

Looking for used/old "no back clutch spring" (electric gear)

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Sams    1

Good morning,
you experienced Mooney drivers probably already heard of the very expensive and infamous no back clutch spring as part of the electric gear assembly. According to M20-282A, it shall be replaced every 1000hrs.

I am wondering, if anybody of you has such a used, old or even broken spring of which I could get a hold of for analysis?! Of course I'd cover shipping + any expenses, come by, ...
For reference see the picture attached (found at in the "spring thread") and here:

http://www.donkaye.com/donkaye.com/Infamous_Back_Clutch_Spring.html

 

 

PS: Sorry, this topic has been x-posted at the EMPOA-Forums.

spring1.jpg

spring2.jpg

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Sams    1

Thanks. I figure, after a thorough inspection of our existing one I'll keep it on stock - just in case.

Just to clarify: I am just looking for a spring to borrow.

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carusoam    4,005

Sams have you seen pictures of surface cracks on the spring where the ends are heated and softened for bending...  the number and size of the cracks increases with time and use.

There was a metallurgy issue that was causing this cracking issue.

unfortunately the broken spring disables the manual and electric gear.

What are you trying to achieve or learn about the spring?

Just trying to be of help.

Best regards,

-a-

Edited by carusoam

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Sams    1
Sams have you seen pictures of surface cracks on the spring where the ends are heated and softened for bending...  the number and size of the cracks increases with time and use.
There was a metallurgy issue that was causing this cracking issue.
unfortunately the broken spring disables the manual and electric gear.
What are you trying to achieve or learn about the spring?
Just trying to be of help.
Best regards,
-a-


Hi,
thanks for your answer. Well, foremost we want to have a real world example to verify our optical tools and/or UV analysis methods and compare a really used and/or broken one to ours.

We also want to understand, what kind of steel and processing has been used here.
(We are kind of in the business...)

Thanks


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carusoam    4,005

Sams,

A while ago, one of our Mooney CFII gurus took a whole bunch of photos detailing the problem with the spring and posted photos on his website.

This is based on some fuzzy old memories of mine, so please bare with me.

Start here...

http://www.donkaye.com/donkaye.com/Infamous_Back_Clutch_Spring.html#grid

 

Maybe it was Don or Somebody else who may have posted close up / 10X microscope photos of surface cracks that were quite visible...

If I remember correctly, there was a photo of a new spring showing a few small surface irregularities and an aged spring showing more significant surface irregularities.

If you have the opportunity to inspect your spring with a microscope/magnifying glass take a look where the bends are at the ends of the spring.

This is intended to help a fellow mooney pilot.  I am only a PP, not a mechanic.  My memories are quite aged and may be less than perfect.  :)

You may have some luck with the search function to find the other photos...  Hyett has also posted some detailed photos of the landing gear drive system.  

Look at their photo galleries...

Please post results of your work when you get it together.  We will all be better off when this is done.

you might find some additional info regarding springs around here... search: spring steel and heat treating and annealing, again really old and probably less helpful memories...

 

Best regards,

-a-

Edited by carusoam

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I think in this day and age of cheap batteries and electric motors you could have one tiny battery exclusively dedicated to running the gear and one motor per gear leg and have a solution that is lighter, more elegant and more simple than the backspring clutch workaround.

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