In article Jim writes:

You spend enough to buy a house on your motorglider and are trying to
save a few bucks on fuel?


Avoiding 100LL is often not about trying to save money.

If you spent that much money on the motorglider, you probably want to feed
it the best fuel for it, which may not be 100LL.

I don't know about the engines used in motorgliders, but the Rotax engines
used in many of the light sport aircraft "prefer" mogas over 100LL, as the
lead content results in shorter service intervals for things like oil changes,
gearbox servicing, and possible engine overhaul.


Alan