Not sure an electric "engine on a stick" is sensible as a new
design for a get you home (turbo) glider - all the drag and
complexity of the erection mechanism/doors etc. Surely the
FES route make much more sense - simpler, less drag, more
efficient.
Of course if you already own a Rotax/Solo shaker stick engine
it might be attractive (outside of EASA land) you lucky
Americans.

When the engine on a stick fails the drag is very dependant on
the individual sailplane: it's not just the engine & pylon there's
often a big radiator too. From recollection the DG400(&PIK20E)
was about 14:1; the DG800B/C a bit better, a previous post
gives 20:1 for the ASH26E; the Antares 20E (no radiator) is
30:1.

Dave Walsh