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MightyH20 t1_jaqaoq8 wrote

> flew for 15 minutes, reaching an altitude of 3,500 MSL

This is quite amazing and could be relatively easy expanded in terms of flight time. The only question I have is how many kilograms of hydrogen did they use for the 15 mins of flight time.


hiles_adam t1_jaqdn93 wrote

>and two large hydrogen tanks with 30 kg of fuel. Beneath the plane’s right wing, an electric motor from magniX was being driven by the new hydrogen fuel cell from Plug Power.
>Today’s 15-minute flight used about 16kg of gaseous hydrogen — half the amount stored in two motorbike-sized tanks within the passenger compartment. Universal Hydrogen plans to convert its test aircraft to run on liquid hydrogen later this year.

Found this in another article because I was curious as well

for 15 minutes of flight a 747 burns 3600L of aviation fuel, or 2880kg o.o that sounds so wrong but thats what google is telling me


MightyH20 t1_jaqk2c6 wrote

Thanks for looking it up! Usefull information that this article has left out imo.

>Today’s 15-minute flight used about 16kg of gaseous hydrogen — half the amount stored in two motorbike-sized tanks within the passenger compartment.

That is interesting. 1 kilograms of hydrogen equals to 33.33 kWh of useable energy. This means the entire flight consumed only 533.28 kWh.

I wonder under what pressure the hydrogen was stored given the relatively small size of the tanks with the total capacity to hold 30 kilograms.

>for 15 minutes of flight a 747 burns 3600L of aviation fuel, or 2880kg

This could be correct though. I know that a 747 uses around 3 to 4 liters of kerosine every second! And shows the massive efficiency difference between both technologies. 3600 L of kerosine equals to 37,564 kWh.

However, the major difference is probably the weight of the planes and that a 747 uses jet engines whereas this was a smaller prop-plane.

Perhaps a better comparison would be a comparison to a standard propellor plane. According to "the internet" a standard propellor plane uses 900 gallons of kerosine an hour or 225 gallons per 15 minutes. That equals to 8888 kWh.


Hydrogen prop plane 15 minutes flight: 533 kWh energy (16kg of hydrogen) consumption.

Standard fossil prop plane 15 minutes flight: 8888 kWh energy (225 gallons of kerosine) consumption


tantricengineer t1_jarnif0 wrote

These systems must store hydrogen at thousands of PSI for the energy density to rival petrol based fuels. The ideal storage state is nearer to 10,000 PSI where hydrogen becomes slurpy-like in composition.

The material science is coming along. One challenge with hydrogen fuel tanks is if a tank is punctured in an accident, you have rapid expansion of hydrogen gas as it equalizes to atmospheric pressure, and a likely fire which has little color. (Look at the FLIR view here: )

This makes it difficult to determine where flames are.

Still rooting for this tech though since it gives us amazing possibilities.


kyckling666 t1_jarrzfd wrote

Guys I grew up with in oil and gas used straw brooms for invisible fire detection.


jawshoeaw t1_jasas4x wrote

in an aircraft I'm guessing explosive decompression is the bigger problem, seeing as visualizing a fire on your wing really isn't changing your plan in the short term lol


tantricengineer t1_jat4mfi wrote

I don't expect these tanks to blow up in flight. I expect them to blow up when most commercial aircraft accidents happen: on the ground / takeoff / landing.


jawshoeaw t1_jat9lnt wrote

Ohhh gotcha. But sadly that’s rarely survivable with current fuels. I could see some edge case where there’s a survivable landing but here’s the actual advantage of hydrogen, the high pressure vessels are necessarily quite strong and might do better in a crash even if the broke open compared to avgas


InsuranceToTheRescue t1_jasszm4 wrote

I believe since the tanks are pressurized that they would likely explosively ignite instead of making a sustained flame. Then these vehicles really could blow up like in the movies.


razorirr t1_jarg2c5 wrote

Its quite a bit more than that. It takes 55kwh to crack the water to get that h2 using hydrolosis

A question becomes then if planes are 10% of us transit emissions, all other large transit 10%, and our personal cars are 45% and semis are 35%. Should we be using energy to do this? That same solar would most likely reduce emissions more if you put it directly into cars / busses / semis as battery electric. You dont have the conversion loss, and BEV is 10-15% more efficent than FCEV


jschubart t1_jas8dvl wrote

You sure your numbers for prop planes are for 15 minutes and not an hour? This looks similar to the size of a Saab 340 which burns about 119 gallons/hr.


empireofjade t1_jaut5t4 wrote

During the test flight of this aircraft only one prop was hydrogen powered. The aircraft was also powered by a conventional turboprop for safety reasons, so your numbers are not right.


MightyH20 t1_jav2d1b wrote

Aah that makes sense. In that case it would be too complex to calculate it.


Gloriathewitch t1_jaqo3sg wrote

This is probably an average, they'd use most of that on acceleration I'd wager, but coasting in the sky takes very little thrust.

Also, fun fact from a mechanic: accelerating briskly to 60mph can increase your mpg as opposed to slowly ramping up your speed, as the burst consumes more however the sooner you coast the sooner you start conserving fuel.

Draft behind semis if you want even better mpg, your car not having to overcome the wind makes the car have to barely work.


asdaaaaaaaa t1_jaqp3ap wrote

>Draft behind semis if you want even better mpg, your car not having to overcome the wind makes the car have to barely work.

They also tend to drive more reliably towards saving fuel than zipping around, changing speed or lanes all the time, and doing other things that would waste more fuel.


InsuranceToTheRescue t1_jasrbz7 wrote

Yeah, but semis always seem to destroy my windshield with rocks, and not being able to see over or around them makes me uncomfortable.


irrelevantmango t1_jaraqdo wrote

Don't get too close behind them, semi drivers can get cranky if they know you are there but they cannot see you in their mirrors.


Gloriathewitch t1_jaslmea wrote

You're good to draft a fair distance as the air is already disturbed.

Its what makes giant brick shaped trucks so great, they disturb the air so much that you can save gas.


_toodamnparanoid_ t1_jask17f wrote

I found that for turbine aircraft you want to get to altitude faster for the same reason. A max thrust climb will burn at a higher rate but you get to altitude so much faster and the burn rate four every thousand feet you climb drops significantly. That's not just to enter cruise but also the efficiency at altitude.


jawshoeaw t1_jasajd4 wrote

would clarify that while slowly ramping can be inefficient, flooring the accelerator, depending on the vehicle can also be inefficient .The principle being an engine under load is more efficient , but only up to a point again depending on design. but in this case, the motor was electric so no reason not to goose it :)


elatedwalrus t1_jaqy6vn wrote

You should also consider the voluke of each fuel. An airliner fits that much fuel mostly in its wings


Icy_Comparison148 t1_jayjfxw wrote

Yeah that sounds about right. That’s a big as jet though, I think it’s 3600 gallons per hour. A 757 burns about a third of that per hour in cruise. A dash 8 burns about maybe 175 to 200 gallons per hour. Which looks like what this plane is based on.


ArtifexCrastinus t1_jaq122t wrote

A short proof of concept flight with one hydrogen-powered engine and one soon-to-be-outdated ICE (for flight safety and comparison). The hydrogen-fueled engine was less noisy and produced less vibrations. They've developed a retrofit kit to use with existing planes and fuel-capsules that ship on existing infrastructure. Sounds like the tech was developed in France, but it's being pre-ordered by many companies arpubd the world. I wonder what pressure we can use to for our local airlines to get on the list?


blisstaker t1_jaq9er2 wrote

if it is 100x less noisy it doesn’t matter, all that will matter to companies is the price and overall operating costs. that’s the pressure we would need, whether from the government, the market, or the consumers


SiTheGreat t1_jaqe3hu wrote

Aircraft noise reduction is actually a pretty big area of research by aviation companies due to noise regulations. Aircraft noise levels limit things like aircraft traffic, takeoff weight, airport zoning etc, so finding ways to reduce it means more money in their pockets.


elatedwalrus t1_jaqym8e wrote

Theyre looking for ways to reduce noise without losing money otherwise tho. Hydrogen powered planes have now room for passengers so it probably wouldn’t work. Hydrogen is also very hard to keep from leaking. Ever hear about how much methane leaks from our natural gas lines? Hydrogen does that but much worse. And its much more flammable


bactatank13 t1_jaqemif wrote

> what pressure we can use to for our local airlines to get on the list?

When they resolve the energy problem regarding hydrogen. What government need to do now is continue to fund and pressure R&D into Green Air Travel. Personally I think we are at least two decades from scalable green air travel. Half of the time will be spent on researching and the other half will be spent proving to everyone it is as safe as ICE. The latter being the hardest part.

" 18 gigawatt-hours every day, equivalent to the full production of one typical nuclear plant of 900 MW. If, to ensure that hydrogen production actually reduces carbon emissions, the electricity is produced through solar power, 44 square kilometers of solar panels would be needed—a footprint representing three times the entire surface area of the Orly airport itself. " source:


Firm_Bison_2944 t1_javclhj wrote

We developed scalable green air travel a long time ago... Dirigibles (zeppelins, blimps). The hindenburg just scared everyone off. These days you gotta watch out for F22s though.


bactatank13 t1_jawxok3 wrote

Neither of those are scalable because their speed and space. Electric air taxis are more economically plausible.


Jimmy-Pesto-Jr t1_jaqqx27 wrote

i wonder if they used compressed gaseous hydrogen, or used an unpressurized liquid fuel like methanol for higher energy density


Flavor_Nukes t1_javu4z8 wrote

I wouldn't be so sure. There are still some massive tech problems to finish out before it's even viable to run both engines with. Pressurization and anti ice are both huge problems. In 99% of airliners, pressurization and anti ice bleed air is coming off the high pressure section of the turbine compressor section. Also electrical and hydraulic power. All currently come off drive generators from the turbines. Making the flip to hydrogen will take a massive amount of engineering to overcome some pretty glaring problems. Theres a long way to go still.


asdaaaaaaaa t1_jaqow6v wrote

>I wonder what pressure we can use to for our local airlines to get on the list?

The real issue is setting up and affording the more boring stuff I'd imagine, infrastructure/training for fueling and maintenance, possibly being certified if they're not already. Those things are nice, but we don't choose fuel types because they're a bit quieter, we go with what's stable, available and cheap. If it provides multiple benefits along with better cost, I don't see why companies wouldn't switch eventually.


jawshoeaw t1_jasbz4p wrote

For anyone who didn't read article: this was an electric motor being tested on one side of the aircraft, with the other being a conventional turbine engine aka turboprop. The electric motor was fed by electricity generated in a fuel cell that used hydrogen as the fuel source. In other words, they didn't "burn" the hydrogen in a turbine engine, This is why the pilot reported it was so much smoother. It was an electric motor. The hydrogen was sourced from water, not from natural gas so was in some sense truly "green"


panzercardinal2 t1_jasjnct wrote

Most everyone is missing the point of UH2. They are creating a proof-of-concept for an application of their primary mission, which is hydrogen logistics. Even if every plane had one of these cells for each engine, there's no infrastructure to supply it.


Now that they've proved this out, it's gonna be a pivot towards HOW TO SUPPLY THE H2 in a manner to support the GIGANTIC number of retrofits that OEM's/operators are going to make. But no OEM/operator is going to make that retrofit until there's a reliable supply that supports their ops, so the comments worrying about the efficiency comparison are missing the forest for the trees.


pgabrielfreak t1_jas76mg wrote

Gotta love the name, Lightning McClean. This is great news!


Maxpowr9 t1_jarlf1v wrote

I feel Toyota had the right idea but wrong application. Hydrogen is the future for the airlines and commercial vehicles, but not for personal vehicles.


Projectrage t1_jaubk2o wrote

Storage is the problem…very leaky atom. NASA hasn’t even figured it out.Bad for commercial vehicles and airlines.

It’s better to use hydrogen for marine use or for manufacturing.

Toyota lost big and contributed hard to oil companies for the hydrogen part. They are now finally going to EV. But they are way behind the 8 ball.


Parchabble t1_jarx6s7 wrote

Why? As hydrogen gains more popularity it's going to become cheaper and more efficient to extract. In fact, companies are already pushing for Green Hydrogen technology and looking at new methods of extraction and conversion.

There is always a give an take when it comes to new technology and the truth is that batteries and hydrogen are not quite there to force it on the market. If solid state batteries become a reasonable alternative, than EVs can make sense for personal vehicles, but if hydrogen is more cost effective and readily available it makes complete sense as a clean fuel source for personal vehicles


QuineQuest t1_jasplou wrote

There are alt least two major problems with hydrogen:

  1. Converting from electrical energy to chemical (making hydrogen) and back again is hugely inefficient. As in losses in the 60% range. By comparison, storing the energy in a battery and extracting it again carries about 10% loss.
  2. Hydrogen isn't very dense. It will take up a lot of space. To make a 373-size plane that can cross the Atlantic, there wouldn't be any space left for passengers.

Parchabble t1_jasut80 wrote

It's this type of thinking that causes us miss out in advancements in technology. The current hydrogen extraction method is Grey Hydrogen which is done using fossil fuels. Since fossil fuels are still a critical aspect to our energy needs, it isn't going away anytime soon. However, trying to figure out how to maximize and efficiently produce blue and green Hydrogen is a critical next step.

Hydrogen has been used in the aerospace industry for awhile now, and Blue Origin and SpaceX are both utilizing it. With commercial aviation taking hydrogen as a serious fuel alternative, a near future ramp up in production will be needed.

Add in the fact that commercial trucking is buying into the Toyota Hydrogen truck and the Nikola and Hyzon are also gaining momentum, the actual users are seeing better buyin and will need a better supply.

The current model of EVs should get more scrutiny than it does. Ford F150 is being scrutinized, but lithium mining as a whole is not great for the environment

I think investment into technology like solid state batteries is great. In fact, Toyota leads the charge in securing patents for that technology as well. But, when innovation drivers like Toyota are looking at something like Hydrogen, it makes sense to take them seriously.


QuineQuest t1_jasz2gn wrote

Sorry, but you sound like you're paid by Toyota.

Producing green hydrogen isn't anything new - we did it in physics class in school. Maximizing efficiency isn't a new idea either, but there isn't a lot of gains on the front in the horizon.

And yes, Hydrogen-powered, Rocket-propelled space flight is absolutely a thing, but it doesn't have a lot in common with commercial passenger flight as we know it. Those rockets also have a pretty abysmal weight-to-payload factor.

I'm not saying we shouldn't use hydrogen (in fact I'm working for a company that makes elctrolysers for producing green hydrogen). But let's start with the low-hanging fruit: Steel production, fertiliser production. Things that doesn't move at 800 km/h.

Fully charged has more on the subject

Edit: wrong link


Patriot009 t1_jau2sqr wrote

For personal vehicles, my bet is on sodium ion battery EVs. Far cheaper to manufacture, far less environmentally destructive, far less toxic. I think the abundance of material and cheap costs will make up for it being a little less energy dense than lithium.


sweetpeapickle t1_jat4m4b wrote

First thing I pictured-Hindenburg. Yea, I know-different use. But still....


[deleted] t1_jarukio wrote



Drewski346 t1_jas2sqg wrote

There's a fairly wide margin between using hydrogen as your lift material, and using it as a fuel source.


squarepeg0000 t1_jaqmqij wrote

Um... wasn't the Hindenberg a hydrogen powered air ship?


chowindown t1_jaqofry wrote

It was filled with hydrogen for buoyancy. Its engines ran on deisel. A bit different.