Hi Tom
Most likely is excessive vibration, like when you lose a prop blade or
heavy landing/prop strike
Be nice to know though. ;-)
Graham
Tom Friedland wrote:
> Hi Graham
>
> I doubt that you will get an answer what caused the break. It looks
> to be that it was most likely a tension break with perhaps some
> fatigue factor. The upper tubes will have tension in the upper parts
> and that will be increased by the thrust. There also could be some
> problem with non annealed brittleness from the closeness of the weld.
>
> The lower tubes should be ok as they have tension stress from weight
> bearing but that is cancelled by compression.
>
> But then what do I know. My engineering studies were 50 years ago!
> Now I am just a dumb doc.
>
> Tom
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