Richard Riley wrote:


Believe me, I've been doing the trade studies for the last 3 years.
You can't buy a COTS fuel cell, and the volume required to store H2
(not to mention the handling difficulties) mean it won't be used as a
fuel for anything but very high end, special purpose machines for a
very long time to come.

How does liquified methane (at high pressure, ambient temperature) look
to power a conventional internal combustion engine, or perhaps even a
methane fuel cell?

I think that methane requires somewhere around 3700 psi to compress it
into a liquid at normal temperature, surely there's got to be some
carbon-fibre reinforced, aluminum polyester-lined composite tank
technology available nowadays that can handle the pressures necessary
to handle non-cryo liquified methane, without being prohibitively heavy
for an aircraft. Methane has a motor octane rating of around 130 in a
piston engine too, and you certainly won't be needing a fuel pump, just
a good strong pressure regulator / phase change heat
exchanger/gassifier at the tank's output valve to feed a direct fuel
injection metering system for the engine. You could probably employ the
phase change heat exchanger as a clever way to air-condition the cabin
too! (just make damn sure of no leaks)