The Dreamline kool-aid acid test

Some people seem to be getting very excited about a new Boeing hydrogen propulsion project that uses a hydrogen engine in an unmanned, high-altitude aircraft. They couldn’t have read the whole release, because they’d realise we’re basically talking about a small aircraft with a propeller that can carry a bakkie-load or so. So it’s about as advanced as Baron von Richthofen’s tri-plane, except that the wings are mounted end-to-end so it flies a little higher, and it has better spy cameras.

The Register rips into it, and I won’t even try to compete:

World-straddling arms’n'airliners behemoth Boeing yesterday … made an unexpectedly loud splash, with the new motor being described as a “wunderengine” and the “future of aviation”, not to mention “a good option for reducing carbon emissions”. It even got Slashdotted, by the put-it-in-a-car dept.

Actually, it’s in a car - the Ford Fusion. That’s because it’s really just an ordinary four-cylinder car engine, fitted with a turbocharger so as to run at 65,000 feet. Ordinary car petrol engines can run on hydrogen without too much trouble; the problem is building a tank which will hold the cryogenic fuel without it all boiling off.

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As for this sort of gear being the future of aviation, or reducing carbon emissions, steady on. Very slow prop planes aren’t going to be much use for anything except surveillance and comms relay, really - that’s what the military want them for. Maybe it will become easier to run ordinary piston engines on hydrogen lower down, where it’s noticeably warmer and the fuel will boil off somewhat quicker - indeed, BMW has a demonstrator car that can run on hydrogen now (though its fuel does all boil away in a matter of days, potentially causing the garage to explode if you’ve rashly parked it inside).

You could run ordinary turbofans on hydrogen too, with a bit of fiddling; but you’d never fit much of it into ordinary planes. It would only be a goer in various exotic hypersonic designs, where advantages in speed might make it worth one’s while to fill most of the fuselage with weight-efficient cylindrical hydrogen tank. That might be the future of aviation; car engines and propellors won’t.