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Hydrogen powered aircraft.


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5 hours ago, octave said:

Aren't we talking about hydrogen fuel cells rather than CNG?

That's the main subject but it's interwoven with the need to look at the fuel source, characteristics, engineering, emission etc. and there's a parade of them which have come through, all exciting in the beginning.

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On 11/04/2021 at 8:49 AM, Bruce Tuncks said:

I reckon the future might have synthetic liquid fuels. For example, methanol ( CH3OH ) is what model planes used to use before being ousted by Li-Po batteries. If you have hydrogen, I think it relatively easy to make methane (CH4) and then methanol.

I dunno if I agree with you kgwilson. Electric battery planes are cost-effective right now for some applications like training and gliders. A tenfold improvement would see battery power good for most of us who fly for an hour or two most of the time. And they sure displaced methanol model plane engines just on convenience grounds, with no incentives at all. I changed because the model plane stays clean and oil-free,  and going model flying is much simpler.

I do have several methanol models which are unused these days.

But don,t you miss the scream of an OS46 in a power dive to a  low pass ???

  😎

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I'd be happy with any fuel that is environmentally sound, is low cost and provides equal range to existing liquid fuels. I won't miss the racket if it was electric however I can't see batteries improving 10x or hydrogen becoming a fuel. Hydrogen just too big and expensive, liquifying it costs even more and we can't make it efficiently.

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Yep, I loved the smell of the methanol but not as much as the diesel fuel ( ether was the best bit ) of my youth.

But the oil was sooo messy ! And electric power is just so easy in comparison.

OS even tried to break into the electric market...  that was sad I thought. So you guys please keep on with the methanol motors.

There was one guy with a powered free-flight thing I was flying with who got real jealous at how I could turn on power from the ground with the electric thing. So I got several goes to try and find a thermal and he only got one.

Hey I even saw electric control-line models flying...  who would have predicted that?

 

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16 minutes ago, Bruce Tuncks said:

Hey I even saw electric control-line models flying...  who would have predicted that?

No surprises when people have understood the physics of power demand vs rate of battery life; there are quite a few logical applications for electric power; wheelchairs, golf carts, bikes, power tool skins/multiple batteries - even fishing reels.

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54 minutes ago, Bruce Tuncks said:

And short-range cars. At the moment, a 2 car family should have one electric.

I'd be careful; the Millenials are regularly calling on people your age to sell your house for affordable housing and move into a single bedroom flat "because you don't need a big house any more".

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The latest generation of electric cars are no longer short range. Some have greater range than most ICE cars. The only issue is time to recharge & that is coming down all the time. Anyway after 500km or so you need a break & fast chargers can charge to about 80% in 20-30 minutes & developing technology is reported to be able to fully recharge new battery types in 5-10 minutes from dead flat.

 

Hydrogen is easy to produce via electrolysis & given the vast amount of sunshine in Australia, in the future there will be oodles of spare power generated by wind & solar to do this.

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Ammonia NH4 looks like a good way to store Hydrogen. Excess hydrogen could make synthetic fuel with captured carbon. Hydrogen is difficult to manage. it leaks the most of all gases and can make metals brittle. Nev

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My own children have suggested, downsizing, with a holiday on the spare cash !.

BUT

By the time we pay all the lawyers & real-estate fees. Plus that government taxes, ( stamp duty ) etc., 

We wouldn,t be financially any better off.

SO we sit in our little suburban box, and keep those spare rooms ready for somebody/ anybody who drops by. 

The latest Great Grand Son  , with his parents suddenly dropped in for a couple of days,

SO 

Took them into Sydney for a day out. Marvelous !. 

BUT, wore me out, babies ho  so cute, but aren,t they heavey ?.

spacesailor

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The thing about hydrogen, for cars anyway, is that it doesn't make sense.  You use a lot of electric power to produce it - so why not just use electricity?  It's an added layer of complication and power wastage.

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12 hours ago, Marty_d said:

The thing about hydrogen, for cars anyway, is that it doesn't make sense.  You use a lot of electric power to produce it - so why not just use electricity?  It's an added layer of complication and power wastage.

Too logical for most in charge to comprehend ,Marty..

I wonder, if it ever comes to pass , where does this hydrogen come from ?? oh that's right ......water . Another FINITE resource !!

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They DID use electricity .

For years, we had electric milk carts, AND all the TRAMS were electric.

BUT

Pollies & Bureaucrats deemed ,for some reason to delete the metal rails .

Then, when we had electric omnibuses,  they tore down the overhead wires.

Someone got rich from that scrap.

NOW

We will replace those unsightly rails & those ugly wires, bring back the 1940s tram,s, RENAME  them little railways.

SO someone else can get rich.

SO wHY CAN,T WE USE THE ' OVERHEAD WIRES ' FOR OUR electric cars   !!!.

Cheaper than ' Battery powered ' cars.

spacesailo  ( stuck key again ))

 

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33 minutes ago, spacesailor said:

SO wHY CAN,T WE USE THE ' OVERHEAD WIRES ' FOR OUR electric cars   !!!.

 

Can you just imagine Cars Guide coming out with a report, "Award winning Electric SUV design" utilises spring loaded roof mount from antique trolley bus, to connect with power source"?

It wouldn't look to flash in some peoples eyes.🤣

 

 

Edited by planedriver
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We had electric fork lift trucks also; I worked on the design of some components including the acceleration module.

LPG did the same job in cool stores and was more versatile with greater range so that replaced electric.

If someone invents a better battery they could come back in.

 

Electric milk carts died because home delivery of milk died, so not becaise of any shortcomings; they replaced the horse and cart where the horses learnt the route and the driver could run to the house and back to the cart which had automarically moved on. Now and again there was some urgent shouting as the horses made for the depot. This would be an autonomous application today, but it's more economical to deliver milk in hygienic cartons to supermarkets in semi trailers.

 

The trams are still electric, in the application where very heavy vehicles take advantage of an electric motor's ability to deliver maximum torque for startability from 0 km/hr. Same for commuter trains, but both pull power direct from the easter States grid because high torque = very fast battery drain.

 

The cable electric omnibuses were replaced by diesel, not for technical reasons, but because diesel was more useable; it could change routes instantly, take detours to avoid road closures, and be rediverted instantly. For example some years ago there was a tram strike at the time the Formula 1 GP was on in Melbourne. Hundreds of route buses were chartered, they ran along the tram lines and there was no loss of service.

 

There has been some experimentation with electric and Hydrogen fuel cell route buses. Hydrogen fuel cell buses worked very well in a three year trial with the MTT in Perth, but had an instant death because of the 300% higher cost than diesel.

Electric is a disadvantage with route buses because of the fast drain. The diesel engines on main routes are usually a lot more powerful than on outer services.

 

There is an opportunity for electric on some school bus routes.

 

In coaches, there is an opportunity for electric short distance charter and private school coaches.

 

Many designers have tried to come up with a design to transmit power to cars, starting with the Nikola Tesla invention, others with a road pickup (the achilles heel being when you get out of your lane or take a wrong turn and the motor dies.)

 

 

 

 

 

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5 hours ago, facthunter said:

Water with surplus solar or wind electricity. It doesn't come more cheaper than that.  Nev

Yes it does, compressed air or pumped hydro is cheaper storage. And batteries are just way more efficient.

https://www.spglobal.com/marketintelligence/en/news-insights/latest-news-headlines/hydrogen-technology-faces-efficiency-disadvantage-in-power-storage-race-65162028

https://theconversation.com/hydrogen-cars-wont-overtake-electric-vehicles-because-theyre-hampered-by-the-laws-of-science-139899

https://www.volkswagenag.com/en/news/stories/2019/08/hydrogen-or-battery--that-is-the-question.html

 

Battery electric vehicles have basically won the race. All urban transport will go this path.

 

Current solar systems have about a 15:1 return on embodied energy over their lifetime. So lets allow for a 20:1 ratio in the future. With hydrogen having a round trip efficiencies of 18-46% that implies a system energy return of less than 10:1.  This doesn't allow for commercial realities like profit etc when you're trying to balance your budget.

Then on top of this you're going turn it into Ammonia with the inherent inefficiencies of this process.

 

If you wanted to make hydrogen efficiently and economically I'd just be using high temperature nuclear with a direct thermal process such as the Iodine Sulfur process. That way you can make it in your backyard so to speak. I suspect a number of countries with steel making industry will realise this rather than buying expensive NH3.

 

Edited by Ian
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The long and the short of it :

 

Hydrogen is hard to store volumetrically competitively.

 

Making hydrogen from electrolysis sux.

Best is reforming from natural gas etc. But then you might as well run AVGAS.

So, hydrogen might be good for buses, trucks.

Battery tech needs a 10x leap. Wait 10-15 years.

best option right now is a motor driving a prop, 15 minutes of battery , and a wankel engined gasoline generator holding the whole thing up.....

 

electric motor and 1 hour of circuits from a battery is quite feasible right now. good for training plane but little else.

 

 

 

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1 hour ago, RFguy said:

The long and the short of it :

 

Hydrogen is hard to store volumetrically competitively.

 

Making hydrogen from electrolysis sux.

Best is reforming from natural gas etc. But then you might as well run AVGAS.

So, hydrogen might be good for buses, trucks.

Battery tech needs a 10x leap. Wait 10-15 years.

best option right now is a motor driving a prop, 15 minutes of battery , and a wankel engined gasoline generator holding the whole thing up.....

 

electric motor and 1 hour of circuits from a battery is quite feasible right now. good for training plane but little else.

 

 

 

What about when it's used in the fuel cell process to generate electricity to drive the wheel motors.

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mmmm good question...well , fuel cells are a bit of a dog because the membranes that basically strip off the electrons are very easily poisoned, so the H2 needs to be extremely pure.

There hasnt really been too much success in this area to my knowledge.  IE reducing sensitivity to impurities.

Now, what electrolysis has going for it is that it provides a supply of very pure hydrogen.  Whereas the reformers/scrubbers from natural gas etc are not so good in that department.

My statements may be a little out of date but to my knowledges this is still a sticking point.

 

So, solar panels >> electrolysis >> tanks of very pure hydrogen  is a fantastic overall solution, just that electrolysis is a rather low volumetric efficiency process. You need alot of it for 'useful work'.

 

 

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