You seem to be confusing materials and design issues with mechanical issues. I expect that I have more understanding of the situation than you do - decades' wor

You seem to be confusing materials and design issues with mechanical issues. I expect that I have more understanding of the situation than you do - decades' worth, in fact. I've even laid hands on - and spun, as best I could - military jet engines that had been partially dismantled. (I've also seen open civilian jet engines up close but have never laid hands on one.) Once you stripped away all of the external paraphernalia their relative mechanical simplicity was obvious, as was the reason why those particular engines had been grounded.