We had a member place a similar level of faith in his FES to that shown above, using it to climb away from unlandable terrain. The system powered up and climbed away as advertised - initially. During the climb, the battery overheated and the FES shutdown, as it's designed to do, to protect the battery and ultimately, the aircraft. The pilot was now at moderately low altitude and presented with an unexpected outlanding (startle factor) over terrain that hadn't been assessed for such (complacency / over reliance on FES). A successful outlanding was achieved in that the pilot walked away unharmed. The glider was extensively damaged.

My personal opinion is that electric sustainers are the future and in time, will be the hands down winner when it comes to glider propulsion. That day is yet to arrive because of current limitations in battery technology, namely energy density and safety/reliability.

I have a jet sustainer in my glider which I love but at the same time don't trust. I climb in the vicinity of my chosen & assessed outlanding field until I feel it's safe move on (terrain dependent but usually 1,800ft or so). A friend, knowing I'd flown over an area with a lot of unlandable terrain, once asked "would you go there in a pure glider?". The answer was yes, because I only ever go to places I wouldn't go in a pure glider, preserving glide out to a landable area. The sustainer is an installation of convenience to me, to get me back to my home airfield instead of sitting in a fly blown paddock in the middle of nowhere. It's not a substitute for basic gliding principles and judgement.

CJ