2G wrote on 4/13/2020 10:00 PM:
Note that electric gliders don't even have 30 minutes of run time, let alone a reserve. All this discussion assumes running the battery totally flat - no reserve WHATSOEVER and perfect battery performance (no degradation for temperature or age). This is an unacceptable level of even token, lip-service safety. GIVE ME A BREAK!

Actually, several of them do exceed 30 minutes run time; eg, the Jeta with the
large battery has a nominal 150km range under power. That's at about 100kph,
yielding a 90 minute run, and a few minutes longer if you include the launch and
climb to 2500' AGL. The AS34 has a similar run time, the miniLak about 60 minutes,
plus launch time.

The discussion does not assume running the batteries totally flat; eg, the GP15
battery is limited to a 90% discharge to greatly extend it's life. Of course,
temperature and age will affect performance, as it can with gasoline gliders.
Electrics do have an advantage at high density altitudes: their power remains
constant, unlike a gas engine.

As for safety, most motorglider pilots know the engine is to be treated as a
convenience, and not an insurance policy. Like a pure glider, we should always be
within gliding reach of a safe landing place.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1