jdmgto t1_iy42tj5 wrote
Reply to comment by TheLianeonProject in 'Landmark achievement': Rolls-Royce and easyJet hail successful hydrogen jet engine test by Wagamaga
Bingo, getting an engine to run on hydrogen isn’t astounding. The problem is how awful hydrogen is for storage. You’ve got basically two options, absurdly high pressure storage tanks, like 10,000 psi+, or cryogenically. Neither will work with existing aircraft. Commercial aircraft store most of their fuel in the wing structure. You cannot reinforce those structures enough for 10,000 psi storage of gaseous hydrogen, and I know the FAA wouldn’t approve of it. Similarly those structures cannot be retrofitted with adequate insulation to store cryogenic fuels, never mind cryogenic containers which will handle the flex of an aircraft wing without snapping. Which leaves filling up the cargo area with tanks, either high pressure or cryo, which both loses all your cargo space and is inefficient weight wise. And I’m pretty sure if you showed the FAA the plans to turn the entire cargo space of a 737 into a 10,000 psi storage tank they’d retroactively pull the airworthiness certificate of every plane you’ve ever built just on general principle. I’m not even sure if you went full cryo that you could get enough hydrogen onboard an airplane to do much more than short range domestic flights.
FalconX88 t1_iy5490u wrote
> commercial aircraft store most of their fuel in the wing structure.
I wouldn't expect planes to look like they do now. There are a lot of different concepts of planes, look at Airbus Maveric. That blended design would create a lot of volume that can be used.
shwag945 t1_iy5rggt wrote
Commercial passenger planes will probably look the same as they do now because of windows. Windows are important for reducing passenger stress during flight and safety in case of emergencies.
Windowless planes have been a commercial dead end for a long time.
FalconX88 t1_iy7zdsv wrote
Most long haul flights I've been on the past years basically had the windows closed for most of the flight anyway. And in a 10 abreast most people don't have window access right now. However, there are also solutions for that, like fake windows with screens or ceiling windows that let in some sunlight.
jdmgto t1_iy7ucth wrote
MacDonald Douglas/Boeing’s original blended wing body BWB from the late 90’s early 00’s was toyed with but passengers hated it. Most of your passengers wind up in the middle of the plane, far from any windows. You’ve also got issues with trying to get everyone off the plane in an emergency. The FAA has some pretty stringent rules about how long you’ve got to do that. You could, in theory, turn the center of the plane into a giant cryo tank and seat people on the sides near the windows but… well you’re building a huge aircraft and then spending most of the volume on a giant thermos instead of things that make you money.
FalconX88 t1_iy7z38a wrote
> Most of your passengers wind up in the middle of the plane, far from any windows
As they do now, but now we have personal inflight entertainment and on long haul you often got the shades closed almost all flight so not that big of a deal any more.
I agree that there are also challenges, but I wouldn't assume in 50 years planes will look the same
mektel t1_iy6lt3t wrote
Just means the current model for aircraft may need a revamp.
Not that I think hydrogen is the way to go, but we settled on this design based on the fuel we currently use. Future aircraft may very well be of a very different design to support alternative fuel sources or constraints.
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