"M B" wrote in message
...
Some disadvantages a fuel can catch fire, the engine
is very hot, have to figure out fuel routing and fuel
tanks, very noisy, needs interesting engine instruments,
needs overhaul, may be damaged by FOD (rocks and such
in intake). An electric engine seems to have only
two major disadvantages: very heavy batteries and
a prop that takes space to turn and to stow. There
was a Luscombe that had a 150hp turbine that I saw
up at Columbia, CA. I heard it caught fire in Texas
a few years ago and was destroyed (although rumor had
it the people survived fine). The turbine idea sounds
neat, but I would personally be a little wary of all
the heat it produces and the very real fire hazards.
But I bet it'd be a real airshow pleaser!

Have you ever seen a lithium cell that had what the manufacturer delicately
referred to as "an outgassing event"?
Granted that fuel can catch fire, at least the oxidizer is not mixed in with
it. It only burns on the surface.
A high energy density battery is more like a rocket engine -- or a bomb.
The fuel and oxidizer are already mixed together, and so reactions can
happen very quickly.
This is not to say that batteries are bad, just that any high energy density
storage system is going to have safety concerns.
Tim Ward