On 3/25/2011 5:17 PM, Terry Blanton wrote:
Per US galloon:
Gasoline = 115,000 BTU
Liquid H2 = 35,000 BTU
Yeah, other than being "green" I see no advantage to using liquid
hydrogen in a combustion engine.
You are wrong. For aircraft, you have to measure BTU per pound (or MJ
per kg in civilized units). The aircraft shown in the photo is fat,
because it is carrying a large volume of fuel, but that fuel weights
much less than other liquid fuel.
In the book about (conventional) hydrogen energy "Tomorrow's Energy"
chapter 6, there is a rendering of an passenger jet designed by Airbus,
and a photo of an actual TU-154 converted to hydrogen. The Airbus looks
a little like a pregnant guppy, upside-down. It has a lot of fuel tanks
in an extension to the fuselage above the passenger deck. You would
think that would make it heavy, but the fuel is light so actually
aircraft+fuel together are lighter than a conventional kerosene-fueled
jet, and it has a much longer range.
I am sure the Boeing unmanned aircraft uses conventional combustion
technology, as they claim. 4 days is reasonable. There is no over-unity
involved. Heck, they have even flown manned aircraft around the world in
9 days (The Voyager, 1986).
- Jed
