Boeing Hydrogen Powered Drone First Flight

garymortimer writes with news of the test flight of a hydrogen powered UAV. From the article: "Phantom Eye's innovative and environmentally responsible liquid-hydrogen propulsion system will allow the aircraft to stay on station for up to four days while providing persistent monitoring over large areas at a ceiling of up to 65,000 feet, creating only water as a byproduct. The demonstrator, with its 150-foot wingspan, is capable of carrying a 450-pound payload."

Comments

So It's Come To This.

[Rie Beam]

Environmentally-responsible airplane that can also carry a wicked-heavy bomb....*sigh*

Re:So It's Come To This.

[Anonymous Coward]

What if it used a hydrogen bomb? Wouldn't that be more environmentally friendly?

Re:So It's Come To This.

[bws111]

So 'payload' means bomb? Since when? And do people really think you could make the bomb-carrying mechanism, bomb doors, and a bomb all fit in under 450 pounds?

The payload is cameras and associated equipment.

Re:So It's Come To This.

[Sponge Bath]

I think Kevin Smith is still under 450 lbs, and he's created a few bombs.

Re:Bomb strapped to a bomb?

[EmagGeek]

One of the coolest things about Hydrogen is that at the pressures required to keep it liquid at room temp, it is a supercritical fluid, which means it is both liquid and gas.

What makes this cool is that, upon loss of the pressure that is keeping it liquid, it will spontaneously switch to its gaseous state. And, this change is not mediated at all since a supercritical fluid has no heat of vaporization.

In other words, the fuel source works at all temperatures, even the -50C found at altitude, without requiring an external source of heat.

Of course, the bad part happens when there's an accident, and hundreds of gallons of supercritical H2 suddenly become several hundred thousand cubic meters of H2 gas, which is not exactly what you want to have around when there's a lot of energy being dissipated by mangling metal.

Re:Water as a by-product

[Lord_of_the_nerf]

If by 'watering' you mean 'bombing' and by 'crops' you mean 'insurgents' then officially 'no'.

Great!

[BitHive]

Is the facility where these violations of our privacy are orchestrated going to be solar powered?

Re:Bomb strapped to a bomb?

[jklovanc]

Which is why under enough pressure it becomes a super critical liquid.

Re:Bomb strapped to a bomb?

[Anonymous Coward]

Traces of thermite... You mean rust and aluminum? I find it hard to imagine that a plane made almost entirely of aluminum crashing into steel beams would leave traces of rust and aluminum!

Hydrogen is not carbon-neutral

[bmo]

All these shenanigans about Hydrogen being a perfectly clean fuel ignores the fact of where it comes from.

We don't get hydrogen from splitting water. That costs too much. We get it from natural gas, which has 1 carbon atom and 4 hydrogen atoms. This is done by steam reforming, and while it's possible to sequester the resulting CO2 by injecting it underground, it's not done by anyone. Because, again, it costs money.

We can also get it from coal, after conversion to "town gas" and that's not the cleanest of processes either.

Yes, I'm jaded. I used to be a true believer in this stuff, then I read more and grew up.

--
BMO

Why Hydrogen you ask?

[fluffy99]

While hydrogen sucks for density per volume at 5.6 MJ/liter versus gasoline at 34 MJ/liter, it's actually has good energy density by weight with 123 MJ/kg versus gasoline at 47 MJ/kg. The huge bulbous body of this thing is simply to store all the fuel. I suspect their main reason for going hydrogen was that it's easier to burn at high altitude and has a wide useable fuel/air ratio.

This low energy density per volume, is also the reason why it can't really be used for trucking. You'd take up half of the usable cargo room just to get the equivalent amount of energy as a normal diesel fill.