In article ,
Richard Riley wrote:

On Fri, 26 Oct 2007 11:49:47 -0400, Orval Fairbairn
wrote:

In article ,
Richard Riley wrote:

There's more energy available in a pound of liquid hydrogen than in a
pound of any conventional hydrocarbon like jet fuel. The LE (Long
Endurance) part of HALE is the basic design goal.

A pound of LH2 has about 2.6 times as much energy as a pound of
gasoline.

The temperature at 65k isn't significantly different from 50k - jet
fuel would work fine.


But when you weigh in with the tanking required to keep the stuff, the
net system energy (fuel + tank) gets out of hand.

Then one would expect the Boeing HALE to incorporate an extraordinary
lightweight tankage system, wouldn't one?

No.