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Meijzlik spinner backplate breakage

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Old 06-26-2017, 09:15 AM
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juance
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Angry Meijzlik spinner backplate breakage

Hi all;
I have a 5", 2-blade Meijzlik spinner running on a DA170 engine that was shaking a lot from day one. The spinner back plate broke three of the 5 spokes right at the round part of it. I blamed the high vibration at the beginning.
The engine was sent for check up and DA replaced one piston/cylinder. It came back way better than it was.

This week end, I got the same problem with brand new back plate. Sheared off two of the five spokes. Prop and spinner are perfectly balanced, properly torqued.
Is the back plate the problem? Any one has experienced similar issues ? Comparing Meizlik back plates with other brands, it looks weak at the base, and long term vibration could case fatigue. I don't know the exact aluminum allow it is built from, but a very strong aluminum might be the problem.

Any comments ?
Thanks
JC
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Old 06-27-2017, 05:27 AM
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Default Backplate breakage

..

Last edited by CK1; 06-27-2017 at 05:31 AM. Reason: Double post
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Old 06-27-2017, 05:30 AM
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Default Backplate breakage

A few things come to mind.
The first is a bent spinner bolt. A bent bolt will throw the cone tip out of center shifting the center of mass . Roll the bolt on glass and if it wobbles at all replace it ..
Second is overtightening the spinner bolt and flexing the backplate will pre stress it.
Third is the balance of the spinner cone itself may be off .Ooops... Sorry , you said that you have already rechecked the balance.
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Old 07-19-2017, 07:09 AM
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juance
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It is a Meijzlik carbon fiber spinner, not an aluminum one.
I have compared the Meijzlik with other brands and it has narrower spokes at the inner circle. There is a stress concentration that breaks it. It is a combination of things, but I can say it is weak for a 170, which is known for its high vibration.
I won't use them anymore.
Thanks!
JC
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Old 07-19-2017, 08:56 AM
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Suggest you post your question over on FG if you haven't already, not much GS traffic here for a number of years now....
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