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doctor_morris t1_iy8kixl wrote

Great fuel, just leaky and requires a lot of volume to store.

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i-am-dan t1_iy8n9tk wrote

And goes BOOOM

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doctor_morris t1_iy8uyi2 wrote

(All the good fuels go boom)

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Buca-Metal t1_iycfc20 wrote

Can hidrogen fuel melt steel beams?

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QVCatullus t1_iyco2y4 wrote

Very much so, if you'll let me react it with chlorine gas and dissolve it in deoinized water first.

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QVCatullus t1_iycmzta wrote

Yep. The fuel is crazy light, perfect for planes and rockets. The fuel tank is very much not.

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Up_in_the_Sky t1_iy9cfen wrote

It's got a fiberglass air-cooled engine and it runs on water man.

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ismbaf t1_iy9cm8z wrote

This is very encouraging. I can envision a time in the not so distant future where the benefits of marketing your aircraft operations as very low emission (in comparison to contemporary jet fuel) will outweigh the financial burden of its early usage. It is nowhere near a direct replacement or a silver bullet solution but rather a possible alternative in selected applications and segments of aviation. But the hard truth is that aviation has a growing and glowing target on its back (as it should, the atmosphere cannot continue to be used as a dumping ground for carbon pollution, that crap has effects that are bad for all of us) and needs to adapt quickly to remain viable in the future.

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thekrucha t1_iy9seur wrote

I work in jet engine engineering. There is big focus in my company on offering environmentally friendly solutions, granted they do take some time to develop to aviation standard. As far as I know, it's similar in other companies. There are numerous projects on various level of improvement that are being worked on currently and I'm glad to see this. I thought you'd be happy to hear that.

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ismbaf t1_iya7p2c wrote

Yes indeed it is great to hear. I am also in the aviation industry so I have a vested interest in seeing it adapt to a low emission standard. Cheers.

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NohPhD t1_iya51gy wrote

University of Chicago ran a jet engine on H2 back in the 1950s or 1960s.

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SpecialpOps t1_iya8hwc wrote

This goes on a jet plane so it is literally uplifting news.

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UnCommonSense99 t1_iya6yat wrote

Unfortunately nobody can design a practical hydrogen fuel tank to fit inside an aircraft wing.

Reasons to do with fundamental constraints of engineering and physics.

I mean you could make a tank with insufficient fuel in it or you could make a tank which was extremely heavy, but nobody wants either of those things.

If you want a fly thousands of miles on a jet plane and be green you need to run on biodiesel; This stuff about hydrogen is basically green washing.

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bustervich t1_iyaf1bu wrote

The real problem with future propulsion is about energy density. Find something as energy dense as petrochemicals* and you’ll be the next bazillionaire.

*No I don’t mean nuclear powered planes.

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Quixophilic t1_iyahvjp wrote

>nuclear powered planes

Ah yes! Every plane crash a mini-Chernobyl!

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Master_Bayters t1_iyaos3a wrote

Actually a plane would never use a bwr reactor like Chernobyl. So a lot of measures could be implemented to seal the core and prevent meltdown... Mass production of small nuclear reactors never advanced due to the bad reputation nuclear has, not because it's impractical. We would have solved the energy crysis and reach carbon zero a.long time ago. Not to mention saving 5 million lifes due to air pollution reduction.

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bustervich t1_iyb0u2n wrote

Designing a plane that could fly on nuclear power has been tried before early in the nuclear age. I don’t know if technology exists today to make it practical, but making it safe in the event of a crash is another story.

People generally think of black boxes on planes as indestructible, and they are pretty tough. But they’re good for protecting a few memory chips from impact and thermal forces. But even though the boxes are in the tail and designed so that the entire front of the plane acts as a crumple zone, there have been crashes where the black boxes were never found, even though the crash location was known and on land. Now imagine trying to build a containment vessel for some sort of reactor that can keep a plane crash from turning into a dirty bomb while also being light enough to be flown on a plane that also has to carry passengers and cargo.

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Master_Bayters t1_iyca84x wrote

We lost almost 40 years of comercial nuclear study due to the fear mongering that happened after Chernobyl. Some is understandable. I was just stating it wasn't impossible, but the industry went on a completely different path. And yes, to seal a core from impacts would be a pain in the *ss

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dustofdeath t1_iyafyit wrote

It would have more than enough energy density for all domestic flights.

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UnCommonSense99 t1_iyet61t wrote

You are technically correct..... But given a choice between having some small fuel tanks full of biodiesel or some much larger and heavier fuel tanks full of hydrogen; what do you think will work best?

( I assume you realise that it's much easier to run a jet engine on diesel than it is to run it on hydrogen)

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dustofdeath t1_iyexm6x wrote

Hydrogen is 2.8x more energy dense than kerosene for the same unit of mass. But needs four times more volume.

Meaning you actually need less fuel - so it almost negates the increased volume issue. Especially if the efficiency of fuel to thrust is better than fossil fuels.

I believe AirBus is already planning a commercial plane by 2035. So there likely have been developments on how to properly store liquid hydrogen (that eliminates the volume issue). The ZEROe.

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3O3- t1_iycl90b wrote

Very cold take, H2 as approximate 3x the energy density of kerosene (120 vs 40 MJ/kg)

The problem is the size required to store it, not the mass, which is a completely separate technological issue (compression)

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QVCatullus t1_iycntuk wrote

It still goes exactly to what the post you're responding to said. They didn't claim that hydrogen had a low energy density, they said that a hydrogen tank that fit on a plane would either not have enough fuel (like, not even remotely enough -- the volumetric "energy density" of hydrogen is on the order of 1/3000 that of kerosene per atmosphere the hydrogen is stored at, so even with a high-pressure 700 bar tank you need 4ish times the fuel storage), or would have to be rated to such high pressures/low temperatures (for cryogenic storage, which is maybe not a good choice for air travel in any kind of near future) that it would be impractically heavy.

In other words, it seems like your comment is calling out a mistake in the post you're responding to, when really you're just restating it, since precisely the problem at hand the PP was referencing was the compression issue.

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3O3- t1_iyezs2w wrote

It does not at all, since the mass, not space (implied by the original post), is the limiting factor for flight. Imagine a standard commercial plane but 1/2 the seating space is now a fuel tank. There, you already have the 4x space, with no innovation in design, and with 1/3 of the fuel mass. As the original post pointed out however, what is currently limiting the application of H2, is in the mass (and general impracticality) of the current fuel compression technology.

There is definitely room for improvement in storage technology, and there are certainly no “fundamental constraints of physics and engineering” that limit to the mass of containers which store hydrogen to precisely what is currently available.

Simply, planes can be made much bigger (to accommodate the space needed to store the hydrogen even in the absence of significant advances in fuel compression technology) without being unviable (demonstrated categorically by the presence of huge commercial jets), which is already partly offset due to the huge mass savings thanks to very high MJ/kg of hydrogen.

If only The original commenter were working for Rolls Royce, they could have warned them it was useless due to the fundamental laws of physics and engineering, theyd have saved millions, and we would all have been spared this “greenwashing”

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danielv123 t1_iycnhqx wrote

Generally, by energy density we mean volumetric energy density. Specific energy is the common term for gravimetric energy density.

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Ayziak t1_iyb49ut wrote

Something something the humanity

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TheMer0vingian t1_iyd7wjx wrote

Hydrogen powered flight. Hmm, seen this one before. Ah yes exploding blimps that's right. Highly flammable.

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55_peters t1_iya471f wrote

Wonder what the LCA is for new hydrogen engines for the world's aviation fleet versus synthetic aviation fuel via future low temperature electro catalytic routes.

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Informal_Self_5671 t1_iyar52g wrote

I'm glad they're doing this, but why does Rolls-Royce have experimental jet engines? Do they sell jet engines? It's weird.

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Kidrellik t1_iy9cydg wrote

Well, I certainly didn't see a car company revolutionizing jet engines but here we are I guess

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dancingraccoons t1_iy9duw4 wrote

Rollc royce car making business is just a cute weird niche of what they do.

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Sambloke t1_iyaf9lx wrote

No, they're separate companies. Have been for about 30 years.

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Kidrellik t1_iy9e0zm wrote

Are they like one of those companies who are a loy bigger than the thing they're most known for? Cause all I know is they make stupidly expensive cars

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PanachePrime t1_iy9g7f5 wrote

Rolls Royce has been making airplane engines for a long time, all the way back to British military contracts in 1915.

These days they’re still a defence/aerospace company first and car manufacturer second.

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MTLinVAN t1_iya2sqb wrote

They’re two distinct companies. The car manufacturer and aeronautics company are completely separate entities. My dad worked for Rolls Royce aeronautics for 30+ years before retiring servicing airplane engines.

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Kidrellik t1_iy9h4p9 wrote

Well shit, learn something new everyday I guess

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Sambloke t1_iyafcr8 wrote

Something incorrect, they're two entirely separate companies.

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deltahalo241 t1_iy9gof1 wrote

They've been in the Aviation industry for ages, they've been making plane engines since the First World War

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Bigred2989- t1_iya77hl wrote

Yes, just like Toyota and Mitsubishi to name a couple. Civilians familiar with car division but have manufacturing in other industries like aerospace or military. Texas Instruments made your graphing calculator and the javelin missile launcher as another example.

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Master_Bayters t1_iyap4wx wrote

Like Hyundai and their boats. They just make cars for fun. Also Fuji and medical equipment... They make cameras for fun as well

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Airborne_Oreo t1_iy9v5om wrote

The Rolls Royce car company is a subsidiary of BMW. It is a completely separate corporate entity, and currently has no relation to (outside the name) the Rolls Royce that makes jet engines.

Fun fact: Rolls Royce (the aviation/ power plant one) is one of the ‘big 3’ jet engine manufacturers and is a huge player in the industry.

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more_beans_mrtaggart t1_iy9mqz6 wrote

The car company made Rolls Royce Merlin Engines right in the factory in Crewe where they had made the cars.

The factory was anticipated to be a target for the Germans, so the factory roofing and walls were painted with street scenes, with cars and kids, and you can kinda still see this in some of the factory walls.

It’s now the Bentley Engine and Vehicle Assembly plant (Pymms Lane).

Making Jet engines was the next logical step.

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mortenmhp t1_iy9pvt0 wrote

> Rolls-Royce, a business established in 1904 which today designs, manufactures and distributes power systems for aviation and other industries. Rolls-Royce is the world's second-largest maker of aircraft engines

https://en.m.wikipedia.org/wiki/Rolls-Royce_Holdings

While you might know them for luxury cars, they are really much bigger and well known in aviation.

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CommonMan15 t1_iy9u942 wrote

The have long sold the luxury car business and leesed out the brand.

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