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RevolutionaryMove357 t1_iy3x901 wrote

Reply to comment by [deleted] in 'Landmark achievement': Rolls-Royce and easyJet hail successful hydrogen jet engine test by Wagamaga

Right? Look at rockets. Destin from Smarter Every Day on YT toured a ULA facility and the tanks for hydrogen and other fuels are insanely, insanely thin.

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jdmgto t1_iy44jex wrote

Just… ok… so, no. Rocket fuel tanks do not operate at anything like gaseous hydrogen tank pressures. Every rocket that uses hydrogen fuel is cryogenic, and they are all designed with pressure relief valves specifically so that as the hydrogen boils off the pressure is released. None of them are designed to operate at any significant pressure. Even then, while the actual structural component of the tank is thin, it’s covered in a lot of insulation to prevent the hydrogen from boiling off. Also rockets are designed to be loaded in a single direction, longitudinally and aircraft… aren’t.

Cryogenic hydrogen is just an ungodly pain in the ass to work with which is why every non-rocket utilization of hydrogen as a fuel uses pressurized gaseous hydrogen instead. 

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lestofante t1_iy7lxxl wrote

Yes but also that is why Airbus is researching on this.
They think tech may ready to be able to overcome those issues and are gonna try make 3 different demonstrator, one normal frame that burn hydrogen, one lifting body, and one normal frame but fuel cell propeller.
As they are one of the 2 biggest company about planes, I think they know what they can achieve

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jdmgto t1_iy7s01s wrote

It's not that you can't make a hydrogen powered aircraft, you can. The problem is that barring the government just straight up banning conventionally powered jets they won't be able to compete. It is just a physical fact that hydrogen’s energy density is awful and working with it is painful. Any aircraft running on hydrogen will either carry less cargo (people or stuff) or have significantly shorter range or some combo of both.

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