On Friday, February 26, 2016 at 1:01:25 AM UTC-8, wrote:
I am *not* saying that jets installed in the last 3 months are reliable.

I am saying that to judge the reliability of the jets in gliders it is only meaningful consider aircraft with the fully developed specification - just as we would do for any other product.

You did say that "we can't meaningfully judge the reliability of jets based on the experiences of pre-certification installations during the development stage - which includes all the JS1 installations prior to November 2015".. This isn't an endorsement of jet engines installations that are certified, so I stand corrected. I would like to know the differences between uncertified jet and certified jet installations; did they uncover problems and fix them, or is the failure mode still there? You are right: there are a lot of components in any engine installation and it only requires the failure of one of them to prevent a start. The more we share information the better we will understand the strengths and weaknesses of each propulsion system. And don't count on the manufacturers to do this!

Tom