Low Emissions/Battery Powered Aircraft

[KeepItStraight]

Am I missing something?

I keep reading that electric powered air travel is imminent. Heart Aerospace with their ES 19 and ES 30, Eviation with their Alice. Then I see articles like this.
https://www.stuff.co.nz/travel/news/300764103/air-new-zealand-unveils-zeroemission-planes

Which are in a stark contrast to the likes of this which I think is more on the money.
https://www-technologyreview-com.cdn.ampproject.org/c/s/www.technologyreview.com/2022/08/17/1058013/electric-planes-taking-off-challenges/amp/

What are they trying to achieve with what look to be unrealistic claims?

[Wizofoz]

Am I missing something? I keep reading that eletric powered is imminent. Heart Aerospace with their ES 19 and ES 30, Eviation with their Alice. Then I see articles like this.

Which are in a stark contrast to the likes of this which I think is more on the money.
Were there supposed to be links in your post? ETA- AH! there they are!!

As to battery powered aircraft, they are all predicated on batteries becoming much more energy-dense- in other words, wishful thinking. The Alice flew for a whopping 8 minutes. ETA- as your second article says!

Hybrid is also of limited value in aircraft- the major energy saver in hybrid cars is regenerative braking. Aircraft don't use brakes while flying!!

[KeepItStraight]

Ooops, sorry hit the post button before I had finished.

[1a sound asleep]

In 1980 everybody would be flying hypersonic by 2025. We should just skip 2 years of battery flights

[Icarus2001]

Just like Albanese said power bills would drop due to cheap renewables coming on line. Bowen and him make a good double act.

[First_Principal]

I got the impression that the 'hybrid' option was more like the PHEV vehicles that are in use today - electric for short hops, but fossil fuel for anything beyond a certain distance/time. Not sure it's worth the complexity and weight.

With regard to pure electric you're right to be cautious about some of the claims that are made, however it's certainly time to be thinking and developing this tech. I guess at some point someone has to put their hand up to purchase a few machines in order to enhance said development and learn more about how they'll work for their particular operation. IMV the motor and electronics are essentially sorted, it's just the energy store as Wizofoz has pointed out.

One thing, I just wish they'd leave hydrogen out of the mix, call me paranoid but I can never get past this when it comes to hydrogen:

https://www.youtube.com/watch?v=fURATK5Yt30

[kiwi grey]

It's mostly bollocks
I recommend you read Bjorn Fehrm's series of columns on Leeham News for a more realistic take
See https://leehamnews.com/category/bjorns-corner/

[27/09]

It's mostly bollocks
I recommend you read Bjorn Fehrm's series of columns on Leeham News for a more realistic take
See https://leehamnews.com/category/bjorns-corner/
Presumably the powers that be at airlines like Air NZ, Sounds Air and the engineering staff at the likes of Heart and Eviation know the sorts of things Bjorn talks about yet we continue to see headlines like the one I linked.

There is no question that we need to push the boundaries to make advancements but why do they keep on pronouncing in service dates that can never be met with current and foreseeable technology. The only reason I can think of is to scam development money out of various government agencies who know no better. Right now is a good time to be jumping on the EV band wagon/gravy train, might as well join in before they miss out, no matter the totally unrealistic goals will never be achieved.

[Wizofoz]

Presumably the powers that be at airlines like Air NZ, Sounds Air and the engineering staff at the likes of Heart and Eviation know the sorts of things Bjorn talks about yet we continue to see headlines like the one I linked.

There is no question that we need to push the boundaries to make advancements but why do they keep on pronouncing in service dates that can never be met with current and foreseeable technology. The only reason I can think of is to scam development money out of various government agencies who know no better. Right now is a good time to be jumping on the EV band wagon/gravy train, might as well join in before they miss out, no matter the totally unrealistic goals will never be achieved.
But the article you linked to doesn't indicate ANZ or anyone has actually committed money to these, they've said they will buy them IF they eventuate.

[PiperCameron]

Presumably the powers that be at airlines like Air NZ, Sounds Air and the engineering staff at the likes of Heart and Eviation know the sorts of things Bjorn talks about yet we continue to see headlines like the one I linked.

There is no question that we need to push the boundaries to make advancements but why do they keep on pronouncing in service dates that can never be met with current and foreseeable technology. The only reason I can think of is to scam development money out of various government agencies who know no better. Right now is a good time to be jumping on the EV band wagon/gravy train, might as well join in before they miss out, no matter the totally unrealistic goals will never be achieved.

It's not just government money available, there's a surprising amount of private equity out there looking for "new tech" to invest in and it's even more surprising just how driven by FOMO they are that they'll happily fork out serious $$$ on the Next Big Thing - just in case it works.

In the end though, for the potential customers it actually has nothing to do with the tech: Think of it as sky-high-risk gambling offset by huge publicity gains all targeted at a gullible travelling public that more than makes up for the money spent/wasted.

[43Inches]

Almost all new airliner types come about through heavy government investment, with the earlier types directly being designed and built in government run facilities. Not sure why people think it would be any different today, the R&D involved for such limited runs compared to road vehicles means they inevitably chew heaps of public money to get up and running. Large corps are progressing very quickly on hybrid and pure electric power-plants currently for aircraft, including P&W and GE, so its not just pipe dreams from small investors.

Look at history, like DHC, they put out the Dash-7 thinking commuters wanted short field capacity, without asking anyone, because hey it's government money. They quickly realised that the small airlines wanted cheap and reliable commuter planes, not short field behemoths, so dropped two engines and called it a dash-8. Canadian gov realised how much aircraft companies cost to run when they have no idea what market they want so sold it off and it's struggled ever since.

I remember when they started spruking diesel powered GA using Avtur. How the engines would be too heavy etc etc. The point in refining technology is to see where it goes to fit in with a new product line. If it was current knowledge how to do something it would be easy, it's creating the technology and inventing it that makes it work. Otherwise we'd all be sitting in caves waiting for lightning to hit trees to capture fire...

One thing, I just wish they'd leave hydrogen out of the mix, call me paranoid but I can never get past this when it comes to hydrogen:

Unfortunately that attempt at scaring the public over some form of Hindenberg re-enactment on a 747 or such shows you have little clue how different materials burn and relative dangers of fuels. Current fuels are far more dangerous than Hydrogen for a number of reasons including explosive capabilities.

The biggest problem we have at the moment is indecision, coming from a point where we have transport powered by one form of base technology. Nobody is putting much R&D into the old tech to make it better, and there is no clarity on what the next mass transport technology should be. Hence the money spend does appear to be random and scattered and players looking to be the next big thing.

[Willie Nelson]

https://www.iata.org/contentassets/d13875e9ed784f75bac90f000760e998/fact_sheet7-hydrogen-fact-sheet_072020.pdf

Worth a read. Certainly a long way to go and there is no end to radiative forcing, just a significant and further reduction on current fossil based fuels.

[First_Principal]

.... Unfortunately that attempt at scaring the public over some form of Hindenberg re-enactment on a 747 or such shows you have little clue how different materials burn and relative dangers of fuels. Current fuels are far more dangerous than Hydrogen for a number of reasons including explosive capabilities. ...


With all respect 43 you cannot know what little clues I may or may not have and, just to be very clear, my post was hardly an attempt to, er, 'scare the public'.

From a flammability perspective I am always reminded of the Hindenburg when it comes to talk about hydrogen as a fuel. I don't think it's a bad thing to be aware of this disaster, not because of the specific nature of that awful failure but because it serves as a bigger picture example of what can happen with 'new' tech and hydrogen.

Practically the use of hydrogen in the Hindenburg was for a different reason, and it was contained differently, than it likely would be today. In a hypothetical modern aircraft it would probably be stored cryogenically or as a gas under pressure, with all the concomitant piping, valves and other paraphernalia needed before it even got to wherever it was going to generate the power necessary to propel the machine. The flammability aspect of hydrogen is just one issue with using it as I see several other possible failure mechanisms already (QF30 is an example), but most of all I just don't get the point.

As I see it you first need to create the hydrogen somehow, which itself will require energy, you then need to store it in a special way (ie. it won't just sit there in any old building ready for use in a simple container like a LiFePO4 battery for example), and when you want to use it you've got to transfer it to the aircraft, after which the system in the aircraft needs to convert it into useful power. While I've made no in-depth study of the comparative total efficiency of a hydrogen system vs electrical battery system it initially seems more complicated and possibly less efficient than 'traditional' electric. Certainly I consider it more risky.

So, while I necessarily retain an open view as to whether hydrogen will gain traction and ultimately turn out to be useful I prefer to put my own effort into other areas, and while I think it unlikely in my lifetime I would not be clamouring to command a hydrogen powered aircraft, nor fly in one.

UPDATE: Willie Nelson interesting article, thanks. I see it also contained a useful comparison of 'safety parameters' ('relative dangers of fuels'?) wrt kerosene vs hydrogen :E

FP.

[43Inches]

Well the main issue is that you posted a picture of the Hindenberg in relation to Hydrogen power, again a transport system that was filled with bags of hydrogen and coated in a highly flammable skin.

Hydrogen as a fuel system if ventilated properly is barely a concern. For instance a leaking hydrogen tank if vented properly will disperse in the atmosphere in seconds, it won't flow backwards onto structures and pool in low lying areas. While the Hindenberg claimed 35 lives in spectacular fashion, aviation oil fuel related fires have claimed thousands of lives over the years, either from engine fires that led to airframe destruction to the spillage and burning after impact. Not to mention oil fuels will stick to you and continue to burn and are toxic as well due to the additives. Once you cut of the H source the fire will most likely cease immediately given that whats left of the fuel will disperse or burn in a few seconds.

Not saying Hydrogen is the answer, but properly done its safer than Avtur for a number of reasons.

PS Fuel air bombs such as Napalm were created due to oily fuels having the ability to stick to a target and then burn continuously and slowly maximising damage to soft structures and humans. With H, Unless you hit the ground hard enough to split the Hydrogen atoms you'll just explode at worst and it will be over very quickly, even then only the area around the tanks will explode, so if located properly might not even affect the cabin. Where after a ruptured Avtur tank you have to evacuate through spreading, burning kerosene if unlucky.

[Flying Binghi]

Seems the thread is about hydrogen. For all its uses the weight penalty of the heavier than air aircraft storage tanks for hydrogen look to be about four times the weight of Avtur. Why not stick to Avtur?

Currently Avtur comes from oil. As oil supplies run low Avtur can be made from coal. We should be off planet before coal runs out..:)

[43Inches]

Seems the thread is about hydrogen. For all its uses the weight penalty of the heavier than air aircraft storage tanks for hydrogen look to be about four times the weight of Avtur. Why not stick to Avtur?

Currently Avtur comes from oil. As oil supplies run low Avtur can be made from coal. We should be off planet before coal runs out..:)

You've missread that. Hydrogen requires 4 times the volume, but is lighter for the same mission load. So space is the issue, for less weight than Avtur. Considering planes are pretty full of empty space its just a design rejig rather than real problem.

[PiperCameron]

You've missread that. Hydrogen requires 4 times the volume, but is lighter for the same mission load. So space is the issue, for less weight than Avtur. Considering planes are pretty full of empty space its just a design rejig rather than real problem.

Then there's this: https://www.australianflying.com.au/latest/aviation-h2-to-explore-liquid-ammonia-for-turbofans

For all of the reasons cited thus far, plus a couple more, likely the most realistic way to use "hydrogen" to fuel an aircraft is starting with Ammonia - which isn't the greatest idea either, but you have to start somewhere I suppose. Using cryogenic fuels on a passenger-carrying aircraft would be so insane it isn't even on the table.

[Flying Binghi]

You've missread that. Hydrogen requires 4 times the volume, but is lighter for the same mission load. So space is the issue, for less weight than Avtur. Considering planes are pretty full of empty space its just a design rejig rather than real problem.

Yes, and no.

I had read a motoring article a while back where it were commented that the dry weight difference of the petrol powered Toyota Corolla to the similar sized hydrogen powered Toyota Mirai were about 400kg. I breezed through the aircraft article and afterwards ‘remembered’ the two articles together.

So yes, a stuff up on my part. Though the weight difference of cars at least shows the hydrogen system looks to be much heavier.

[43Inches]

Yes, and no.

I had read a motoring article a while back where it were commented that the dry weight difference of the petrol powered Toyota Corolla to the similar sized hydrogen powered Toyota Mirai were about 400kg. I breezed through the aircraft article and afterwards ‘remembered’ the two articles together.

So yes, a stuff up on my part. Though the weight difference of cars at least shows the hydrogen system looks to be much heavier.​​​​​

Also depends on the type of propulsion, whether it's buring the hydrogen directly in an ICE or whether its fuel cell technology which I beleive adds weight to the system.