Electric and Hydrogen aeroplanes - feasibility and issues

The only viable solutions (IMVHO) are a) SAF, short term and b) long term: ammonia fuel, cracked into hydrogen (wasn't REL on the case, a while back ?)
How hard would it be to crack NH3 into LH2, onboard airliners ? NH3 is easy to store but only has half kerosene energy. Hydrogen has 2.7 times more energy than kerosene, but is a colossal PITA to store and handle (not the wings, forget the wing fuel tanks).

https://newatlas.com/aircraft/reaction-engines-ammonia-aviation/
https://newatlas.com/aircraft/react.../?itm_source=newatlas&itm_medium=article-body
 
I see the silver lining. Big, big problem with burning NH3 in place of kerosene: Nox. That's the real bastard there. By cracking ammonia into LH2, the Nox issue could be diminished. Not too hard to understand why: the stuff burning inside the jet would be pure hydrogen, rather than nitrogen-laden hydrogen that is: ammonia.
You'd better crack the nitrogen away BEFORE you pour it into the jet engine, otherwise you're up for large amounts of Nox. Which could be even worse than CO2 emissions.
 
Archibald said:
I see the silver lining. Big, big problem with burning NH3 in place of kerosene: Nox. That's the real bastard there. By cracking ammonia into LH2, the Nox issue could be diminished. Not too hard to understand why: the stuff burning inside the jet would be pure hydrogen, rather than nitrogen-laden hydrogen that is: ammonia.
You'd better crack the nitrogen away BEFORE you pour it into the jet engine, otherwise you're up for large amounts of Nox. Which could be even worse than CO2 emissions.
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As posted here before, dumb burning NH3 puts out a lot of NoX.

But using a technology called rich-lean combustion has been demonstrated to give very low levels of NoX even when burning NH3. This method using a secondary combustion zone to further react and reduce the NoX into water and nitrogen;-

https://arc.aiaa.org/doi/abs/10.2514/6.1991-1962
And

https://www.sciencedirect.com/scien...?fr=RR-2&ref=pdf_download&rr=80f6c7013e381c4d
Note:- experimental results a 337ppm NoX which is comparable to kero (SAF) combustor.

Partial cracking of the Ammonia gives the best results.
 
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Archibald said:
The only viable solutions (IMVHO) are a) SAF, short term and b) long term: ammonia fuel, cracked into hydrogen (wasn't REL on the case, a while back ?)
How hard would it be to crack NH3 into LH2, onboard airliners ? NH3 is easy to store but only has half kerosene energy. Hydrogen has 2.7 times more energy than kerosene, but is a colossal PITA to store and handle (not the wings, forget the wing fuel tanks).

https://newatlas.com/aircraft/reaction-engines-ammonia-aviation/
https://newatlas.com/aircraft/react.../?itm_source=newatlas&itm_medium=article-body
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You're not going to crack NH3 into liquid hydrogen, full stop. Gaseous hydrogen, sure. Doesn't matter how much compression you use, hydrogen will not liquefy at 300K. Or even at 30K.

The best way I see using ammonia in a turbine is to use exhaust heat to get some ammonia up to cracking temperatures, and spray the now-cracked gas mix into the combustion chambers to provide heat to burn ammonia directly. Your burners will have two sets of injector nozzles, one for cracked 3H2+N2 mixed gasses and a second for straight NH3.

The trick with that is how to start the engines when cold. Probably the best answer there would be to have an ammonia cracker on the APU as well, with the ability to send the cracked gas to the main engines (and also to run cracked gas from the mains to the APU to start it). As for cold starting the APU at the start of a day or week, probably a small hydrogen tank to run the APU for 10-15 minutes to get it up to working temps.
 
Archibald said:
Very interesting. I hesitated putting the "L" in front of LH2. Ok then, no liquid hydrogen, just gaseous one. Makes sense.
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Yes, you need to dump a lot of heat into ammonia to get it up to cracking temperatures, and then take all that heat back out to liquefy the Hydrogen.

Just because Hydrogen is weird like that, and will only liquefy at cryogenic temperatures.
 
Airbus test fired fuell-celks stack:

The big day took place at the end of 2023, closing out the year on a high for the ZEROe team. After successfully completing testing of the fuel cell system at 1.2 megawatts in June and the powertrain at 1 megawatt in October, the electric motors of the iron pod were powered on with the hydrogen fuel cells for the first time.

“It was a huge moment for us because the architecture and design principles of the system are the same as those that we will see in the final design,” says Mathias Andriamisaina, Head of Testing and Demonstration on the ZEROe project. “The complete power channel was run at 1.2 megawatts, the power we aim to test on our A380 demonstrator.”
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https://www.airbus.com/en/newsroom/...zeroe-engine-fuel-cell-successfully-powers-on
 
shedofdread said:
Further to #489, here's more about the Sirius. This article includes some 'Sirius' attempts at humour...

https://www.flightglobal.com/aerosp...email&utm_source=email&utm_content=newsletter
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Yeaaaah, a combination of aviation present twin silliest quests: hydrogen fuel AND eVTOL. What could possibly go wrong ? I mean, it's like AVS with VG and batteries of liftjets, typical 1960's madness. We have found its 2020's counterpart.

Surprised no aerospace startup ever thought before of combining the two crazes into just one. And they are targeting 2025 for first flight, just to add aditional difficult to the whole thing.
 
GTX said:
https://www.forbes.com/sites/michae...-disrupt-aviation-from-below/?sh=49fca4074e46
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From his Bio, the author has never delivered an aircraft, has never delivered an electrical power architecture and most of his previous experience has been in IBM. Despite this he presents like a subject matter expert. Note to his credit, he’s declared a personal financial interest in pulling in as much research investment as possible.

His comments “Battery energy density is not as significant a constraint as many have been assuming.” really shows a lack of understanding of the Berguet equation and square vs cubed maths. He claims that a battery driving an electric motor is so simple, but the emerging information from the Joby and Vertical accidents shows it’s anything but simple;- indeed the owner of Vertical spoke recently of just how complicated it really is to meet the safety… redundancy, fault response etc.

The distortion of battery energy issues;- although he’s keen to tell that the state of the art energy density, combined with just electricity will be astonishingly cheap but he decided not to mention that presently our best batteries are not up to the discharge/charge cycle;- this will kill them in about a 100 cycles, the replacement of multi ton battery will a big multi million exercise amortised over the number of flights. For his claims to be viable we not only have to double presently used energy density, we have make a battery with 100 times the charging life. Surely an expert would know that?

He’d rather not tell you that his ideal energy density is approx half of that of TNT. Kerosene with a N2 blanket simply cannot ignite. A battery inherently has all the chemical ingredients present to liberate its energy, with the critical reaction elements separated by a membrane a few microns thick. Also best not mention the really practical problems of charging multi ton batteries, the massive conductors (tons/meter), insulation, energy losses, cooling and current switching.

It’s one thing a former IBM keyboard tickler saying he knows it’s all easy, give me loads of money to build my personal fortune, and the engineer that has to deal with all this detail to guarantee a safe solution. Note also his nonsense claim “flight tests before NASA or EASA will allow passengers to be carried” NASA isn’t a regulator that can authorise civil passenger flights….

The present situation with climate change drives these behaviours and there’s no end of people positioning themselves to exploit it.
 
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Zoo Tycoon said:
From his Bio, the author has never delivered an aircraft, has never delivered an electrical power architecture and most of his previous experience has been in IBM. Despite this he presents like a subject matter expert. Note to his credit, he’s declared a personal financial interest in pulling in as much research investment as possible.
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And yet Harbour Air, operating in the Puget Sound in the US and Canada, has electric-swapped all their float planes. (Beavers and Otters and such, very much at the "bottom of the airlines" scale) ~150nmi range plus 30min reserves.

And they're keeping the same schedule they had when running dino-burners, since the planes are able to recharge to the needed levels in the time the plane is normally on the ground between flights.
 
Scott Kenny said:
And yet Harbour Air, operating in the Puget Sound in the US and Canada, has electric-swapped all their float planes. (Beavers and Otters and such, very much at the "bottom of the airlines" scale) ~150nmi range plus 30min reserves.

And they're keeping the same schedule they had when running dino-burners, since the planes are able to recharge to the needed levels in the time the plane is normally on the ground between flights.
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How about a reality check?

https://harbourair.com/earth-day-eplane-update/
They’re not certified, have one aircraft, with 70 test flights,, about 40 minutes endurance, with no passengers, and no validated performance for payload range or reserve.

Any fool can float around at an airspeed consistent with min sink to get the longest endurance but that’s 20-30% of cruise.

The squared cubed thing also means small demo aircraft doesn’t indicate anything will transfer at a larger scale.
 
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Speaking of ammonia cracking, phys.org has a story called "New catalyst accelerates release of hydrogen from ammonia."

Perhaps this can be combined with the tech described here:
"New ceramics promise hotter gas turbines that produce more power."

Also: "Brazilian scientists obtain a material that could be useful for hydrogen production"
 
Zoo Tycoon said:
How about a reality check?

https://harbourair.com/earth-day-eplane-update/
They’re not certified, have one aircraft, with 70 test flights,, about 40 minutes endurance, with no passengers, and no validated performance for payload range or reserve.
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Odd, because that's not what they were saying the last time I saw press releases.


Zoo Tycoon said:
They’re not certified, have one aircraft, with 70 test flights,, about 40 minutes endurance, with no passengers, and no validated performance for payload range or reserve.

Any fool can float around at an airspeed consistent with min sink to get the longest endurance but that’s 20-30% of cruise.

The squared cubed thing also means small demo aircraft doesn’t indicate anything will transfer at a larger scale.
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Honestly, 40min total endurance is about all they need INCLUDING RESERVES. The longest flights they do are their sightseeing loops, the straight shots from Seattle to Victoria or Vancouver BC are right at 20min.
 
Scott Kenny said:
Odd, because that's not what they were saying the last time I saw press releases.



Honestly, 40min total endurance is about all they need INCLUDING RESERVES. The longest flights they do are their sightseeing loops, the straight shots from Seattle to Victoria or Vancouver BC are right at 20min.
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No my link is from Harbour Air own website, the horses mouth as we say.

The distance from Seattle to Vancouver is 142 miles, (Seattle to Victoria is 2.4 miles). So even at the Beavers cruising speed of 143mph it’s an hour.

A lot of folks in the electric aeroplane business (except motor gliders and twin seat VLA) ignore reality…. It gets them investment from like minded rich folks that can’t do the physic’s.
 
Scott Kenny said:
And yet Harbour Air, operating in the Puget Sound in the US and Canada, has electric-swapped all their float planes
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I'm not sure where you got this but I think you will find that the grand total of Harbor Air's revenue generating electric aircraft is currently.... zero
 
Raberto said:
I'm not sure where you got this but I think you will find that the grand total of Harbor Air's revenue generating electric aircraft is currently.... zero
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Press release from Harbour Air in the Seattle Times-Post Intelligencer.
 
They clearly state on their own website under News > ePlane Update that the electric conversion isn't certified, and that this will take even longer than they thought, with certification of battery system for example not even planned to be achieved until 2025. No certification = no commercial operations!

I'm not criticising their great progress in the single Beaver conversion project that they have completed and continue to test and demonstrate, but this will be flying under an experimental permit...
 
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Yep. Tecnam was the first established company to suspend development of their proposed all electric aircraft, citing issues with batteries as the primary obstacle to bringing a viable product to the marketplace.

https://tecnam.com/tecnam-to-postpone-the-p-volt-programme/

"At present, Tecnam believes that these can only be achieved by extremely aggressive speculation on uncertain technology developments."

"After three years of intensive studies covering the entire lifecycle of an all-electric aircraft, Tecnam has concluded that the time for P-Volt is not yet ripe"

"One of the conclusions was that an aircraft with a battery pack at the end of its life would not be the best product for the market, but certainly the worst in terms of Net Present Value (NPV)."

Embraer at present is still officially committed to their Energia project, but their timelines are a bit more realistic. For example, they don't see an all electric 9 seat aircraft being ready for service entry until at least 2035.

https://www.aviationtoday.com/2021/...pulsion-vision-new-energia-aircraft-concepts/
https://tecnam.com/wp-content/uploads/2023/06/Tecnam-P-VOLT-flying-Edited-W230613.jpg
 
MagniX eBeaver's powertrain has yet to be certified by Transport Canada. Therefore, no revenue passengers (or simply passengers...) for now. In April 2023, Harbour Air was expecting certification of the powertrain they are considering for retrofitting their fleet around mid-2025: https://harbourair.com/earth-day-eplane-update/.

Regarding implementation pathways, see also National Academies' ACRP Research Report 236 on electric aircraft and hydrogen technologies at airports: https://nap.nationalacademies.org/c...r-electric-aircraft-and-hydrogen-technologies.
 
alberchico said:
Yep. Tecnam was the first established company to suspend development of their proposed all electric aircraft, citing issues with batteries as the primary obstacle to bringing a viable product to the marketplace.

https://tecnam.com/tecnam-to-postpone-the-p-volt-programme/

"At present, Tecnam believes that these can only be achieved by extremely aggressive speculation on uncertain technology developments."

"After three years of intensive studies covering the entire lifecycle of an all-electric aircraft, Tecnam has concluded that the time for P-Volt is not yet ripe"

"One of the conclusions was that an aircraft with a battery pack at the end of its life would not be the best product for the market, but certainly the worst in terms of Net Present Value (NPV)."

Embraer at present is still officially committed to their Energia project, but their timelines are a bit more realistic. For example, they don't see an all electric 9 seat aircraft being ready for service entry until at least 2035.

https://www.aviationtoday.com/2021/...pulsion-vision-new-energia-aircraft-concepts/
https://tecnam.com/wp-content/uploads/2023/06/Tecnam-P-VOLT-flying-Edited-W230613.jpg
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I wrote something similar, but of course less profounded than here before. Please note, that the Lilium Jet is lacking any cooling openings, despite there is quite a lot of heat produced in the batteries at 2500 kW....
 
alberchico said:
Yep. Tecnam was the first established company to suspend development of their proposed all electric aircraft, citing issues with batteries as the primary obstacle to bringing a viable product to the marketplace.

https://tecnam.com/tecnam-to-postpone-the-p-volt-programme/

"At present, Tecnam believes that these can only be achieved by extremely aggressive speculation on uncertain technology developments."

"After three years of intensive studies covering the entire lifecycle of an all-electric aircraft, Tecnam has concluded that the time for P-Volt is not yet ripe"

"One of the conclusions was that an aircraft with a battery pack at the end of its life would not be the best product for the market, but certainly the worst in terms of Net Present Value (NPV)."

Embraer at present is still officially committed to their Energia project, but their timelines are a bit more realistic. For example, they don't see an all electric 9 seat aircraft being ready for service entry until at least 2035.

https://www.aviationtoday.com/2021/...pulsion-vision-new-energia-aircraft-concepts/
https://tecnam.com/wp-content/uploads/2023/06/Tecnam-P-VOLT-flying-Edited-W230613.jpg
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Interestingly, the Embraer Energia family of concepts features a lot of different ideas. Size ranges from small GA/regional air mobility planes (E9-FE) to larger RJs (E50-H2GT). Some concepts are powered by fully-electric powertrains, others have hybrid-electric propulsion systems, and hydrogen gas turbines are also mentioned. There is also this intriguing note about the larger E50-H2GT concept that "dual-fuel enables us to power a gas turbine with two different fuel sources (SAF or Hydrogen)".

https://embraercommercialaviationsustainability.com/concepts/#energia
 
Great initiative.
I am pretty sure that the shipping industry should embrace the results of this experiment, if positive, to bring similar capability to offshoring and cargo.
 

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