CAFE Electric Aircraft Symposium Set For May 1

On 5/3/2015 10:10 PM, Skywise wrote:
Although liquid hydrogen has nearly 3 times more energy per
unit weight, that does not take into account the mass of the
containment vessel. A liquid hydrogen tank is going to more
than 3 times as massive as a gasoline tank or fuel bladder,
thus resulting in a net loss of energy per unit weight of the
fuel plus it's container.

I'm not sure where you got that information from, but it's wrong.
Compressed hydrogen takes a heavy tank because of the pressure.

On the other hand, liquid hydrogen need not be under pressure, so it
does not need a massive tank. However, cryogenic fuels have their own
issues! What a cryogenic fuel tank needs that is different from other
liquid fuels is insulation. That insulation need not be heavy, but it
will take up valuable volume in your airframe. Also, cryogenic tanks
are always venting unless you have heavy, expensive power-hungry
refrigeration equipment aboard. So that means that your liquid
hydrogen-fueled airplane could be assumed to be sitting in a cloud of
flammable gaseous fuel whenever it is fueled and sitting on the ground.
No thanks!