"J. Clarke" wrote

Right now it looks like he's got a cute little air motor. If it
actually runs on fuel, doesn't overheat at high power, holds together
for a few thousand hours, gives reasonable throttle response, passes
emissions, and if it really achieves the efficiency he claims, _then_
he's got an engine.

The air is used in public settings to meet fire codes. He has run them on
fuel for awhile now. The easiest fuel for it to use is deisel. All of his
initial offerings will be in deisel. He can make a few changes to use other
fuels.

Again, he has to build something beyond prototypes. I wish him the best. It
is a real creative feat. But real life has a way of dashing dreams.