On Tuesday, September 15, 2020 at 5:45:05 AM UTC-4, Dave Walsh wrote:
A real problem is putting the word "KISS" and "FES" is the same
sentence or indeed "KISS" and "electric propulsion".
There is nothing simple about electric motors powered by LiPo batteries.

I couldn't disagree more. Electric motors are amazingly simple and reliable, and LiPo batteries-- in general-- are extremely safe. The issue arises when you start pushing the technology to its maturity limits. At the power/weight/energy limits we want for the gliders we start making compromises which push into research territory. However, that is a far cry from assuming there is anything complex about the system. We just don't know how to use industrial-grade COTS parts to make the glider's system as light as we desire, so we wind up having to have some bespoke parts. The bespoke parts aren't as well tested because the fleet is small, and this is where problems creep in.

The motors themselves have 0 problems and a 20-30kW motor is tiny in the scheme of industrial COTS motors.