I can't wait for electric/hybrid aircraft.

[Charles E Taylor]

- That's the waste product!! You can use (typically) hydrogen, methanol or ethanol to feed a fuel cell. Water can be used as a fuel, but only if you split it into H2 and O2 first - which obviously takes more energy that the fuel cell delivers in electricity.

My original answer was much too flippant.

This Boeing led programme was heavily backed by the Spanish government and Involved lots of Spanish Technologies. The fuel came from the Hydrosol-2 project at Almeria in Spain and is indeed Water based. At least that’s what I was told when I took the photos!
Some more information can be found here. http://en.wikipedia.org/wiki/Hydrosol-2

There are other less appreciated problems with Battery fuel storage for aircraft, one problem being that the “fuel weight fraction” does not diminish during the flight. This leads to significant structural weight increase particularly the landing gear and associated structure.

Current automotive applications involve 600 Volt Systems. Requiring some considerable safety case work, most of which has not yet been examined by experience.

There is still a long way to go.





Charlie

[bookworm]

As Avgas is 12Kwh/kg but engines are only 25% efficient then it means only 3kgwh/kg is used, as electric motors are 85% then any battery about 4kwh/kg or over is about the same as Avgas.

I don't think your numbers are realistic. My 1966 aircraft delivers 150 kW on 50 litres of 100LL per hour. That's about 4.2 kWh/kg. So you're in the right ballpark, but being a bit optimistic.

nanowire batteries that have just been patented

That should ring alarm bells. I think 5 kWh/kg batteries are a very long way away, I'm afraid.

[AdamFrisch]

Why doesn't someone invent the liquid battery for an electric car/plane/heli. Then you could just go to the bowser and drain/fill with freshly charged liquid and go on your way, just like one does with fossil fuel transport.

Well, there are a number of primary cell solutions that work in this way. A primary cell is basically a battery that can't be recharged again. Some of them can be mechanically "recharged" by replacing the material that has produced the electricity.

One such rather interesting cell is the Al-Air cell. It's basically an Alu cathode and an Air anode that produces a lot of electricity. However, it does consume the Aluminium, so once the process is started (often by introducing the saline solution) there's no stopping it. There are a couple of companies that are experimenting with these primary cells where you can quickly just replenish the Aluminium, i.e. refuel, and then be on your way again. Al-Air cells have very good power density. There are other primary cell solutions as well.

Time will tell.

But as for pushing the power consumption up the chain, nuclear powered energy is much much more efficient at producing electricity than drilling for oil, shipping it across the world, refining it and the finally have a super-inefficient combustion engine turn it into propulsive power. Even if electric motors and batteries were less efficient than combustion engines, it would still be a less lossy way to produce all the energy you need in one place than do it at the end user.

[worrab]

You mean this?...

http : // ionicengines.b logspot.com?

[vihai]

Originally Posted by lotusexige

TBH, on the car side I tend to view the current craze for the hybrid as a triumph of marketing and legislation over basic physics.

Only if you don't know how a hybrid works.

The battery is used to *save* energy that would be otherwise be wasted (regenerative braking) and the electric-only drive is used when the ICE would be less efficient because working in unfavorable regime.

The battery in hybrid vehicles, in fact, is very small, able to run the car for few kilometers.

The net effect is a car that consumes less fuel.

A hybrid plug-in or fully electric car is another beast but, if you do the calculations the net energy efficiency (from source to shaft), even from oil-powered plants is greater (not much but still greater) than the ICE.

[gasax]

The fuel consumption of a Toyota 'Pious' is easily exceeded by comparable diesel cars.

The inherent fuel inefficiency of the petrol engine means that the attractive theory is simply not delivered.

The same problem afflects all batteries. After over 100 years of development we have batteries which are significantly lighter and have a higher power density than any imagined at the beginning of the 20th century. Compared with liquid fuelled internal combustion engines it is however still rubbish..............

Basic physics will out.

Dreaming about fission / fusion is also something of a pipedream, yes huge energy densities - until you start to add up all the supporting systems which are necessary to keep it together and stop it taking out a small city. The smallest practical fission reactors are probably in submarines - typically about 2,000 tonnes of 'stuff'.

Suitcase reactors? Not going to happen apart from a military reactor where 'collatoral' damage is irrelevant.

Cann't wait for electric aircraft? Even if you could do a 'Rip van Winkle' at the present rate of progress an electric sailplane is about the best you can expect.

Try flying behind a modern engine and you'll quickly see how pointless an electric aircraft is!

[vihai]

Originally Posted by gasax

The fuel consumption of a Toyota 'Pious' is easily exceeded by comparable diesel cars.

Diesel fuel has greater specific energy and burns at higher compression ratio, thus it it naturally more efficient per liter.

As a Prius owner, the fuel comsumption is actually slightly better than a comparable diesel car.

However comparing to a diesel car is comparing apples to oranges. A Prius with a diesel engine would widely outperform comparable diesel cars.

[A_Pommie]

Cattletruck

Are you sure? The synchrotron at work uses megawatts of energy to produce microamps.

If a diesel hybrid would be so great why did toyota not use a diesel in the pious?

[Big Pistons Forever]

Originally Posted by BackPacker

And as for differences training: the UK CAA already has this covered by introducing the category of "Single Lever Power Control" (SLPC) aircraft, for which they indeed require differences training by a suitable instructor, but no specific exam.

Instructor: OK blogs here is the differences training for your transistion into the bugsmasher NG, now equiped with a SLPC. Now pay attention, there are only 2 things you have to know PTG and PTW

1) PTG = Push to GO

2) PTW = Pull to Whoa

Any questions ?

[BackPacker]

BPF, have you ever flown a SLPC aircraft? Although their operation is indeed very simple if all is well, the failure modes and thus the associated emergency drills are completely different from your conventional Lycosaurus.

The authorized emergency/abnormal checklists for our clubs avgas burning aircraft is one column on an A5 sheet, while the same checklist for the DA-40 TDI runs for two A4 pages. Admittedly that's probably a bit overkill but it was the first diesel in our fleet and they wanted to be thorough. Still, at least one possible failure scenario was not covered in that checklist, almost causing a mate of mine to overshoot his emergency power off landing because the engine all of a sudden went from 0% to 100% power, apparently uncommanded. Quick thinking and quick reactions saved the day, fortunately.

So yes, as far as I'm concerned, differences training is a justified requirement, with an emphasis on failure modes and emergency scenarios.

[Big Pistons Forever]

Originally Posted by BackPacker

BPF, have you ever flown a SLPC aircraft? Although their operation is indeed very simple if all is well, the failure modes and thus the associated emergency drills are completely different from your conventional Lycosaurus.

The authorized emergency/abnormal checklists for our clubs avgas burning aircraft is one column on an A5 sheet, while the same checklist for the DA-40 TDI runs for two A4 pages. Admittedly that's probably a bit overkill but it was the first diesel in our fleet and they wanted to be thorough. Still, at least one possible failure scenario was not covered in that checklist, almost causing a mate of mine to overshoot his emergency power off landing because the engine all of a sudden went from 0% to 100% power, apparently uncommanded. Quick thinking and quick reactions saved the day, fortunately.

So yes, as far as I'm concerned, differences training is a justified requirement, with an emphasis on failure modes and emergency scenarios.

Yes I have flown a SLPC. The power lever was connected to a pair of 4000hp
Alison 506 turbines. Since I had just come from the DC6 with its 4 piston P&W R2800's the list of things I no longer had to do/monitor when demanding more or less power from the engine, was breathtaking.

I think you missed the point of my comment. The fact that it has a single lever power control isn't the issue, it is understanding what is happening to the engine it is attached to. In this respect that there is a definite requirement for differences training. If you take a PPL C172 pilot as a baseline there is far more training involved in making sure a pilot can properly operate an aircraft with a turbocharged, VP prop engine, than any of the current small SLPC aircraft. The whole point of the SLPC is to make the aircraft simpler to operate yet regulators and the flying training industry seem to be making a big deal about this special new SLPC "qualification".

[BackPacker]

Well, I still think it's a good idea that some measure of differences training is required, even if it's just the un-learning of habits. But since the CAA doesn't mandate a certain minimum (at least not within the SEP class) the exact amount is really up to the instructor or the owner. So it can be as little as an instructor pointing you to the power lever, to something akin to a full type rating course.

[vihai]

Originally Posted by A_Pommie

If a diesel hybrid would be so great why did toyota not use a diesel in the pious?

Simply because there is no market. The biggest market for the Prius is in the USA where the diesel fuel is not ubiquitous and more expensive (per liter) than gasoline.

It would also be difficult to obtain the PZEV certification with a diesel engine as the NOx and particulate emissions are greater.

In addition, diesel fuel takes more oil than gasoline to be produced, thus the net efficiency versus the crude oil is reduced.

[A_Pommie]

Fair enough

[BackPacker]

I'm sure everyone has experienced their laptop or phone power gauge going from 100% to 0% in the blink of an eye after the battery reaches a certain age.

What you will probably see is that aircraft batteries will have a sort of TBO number, either expressed in years, or in load/unload cycles. After that TBO number has passed, you are required to exchange them for new (or maybe have them thoroughly tested every x cycles so you essentially use them "on condition").

[FullWings]

Here's a fuel-cell powered aeroplane with a 5-hour endurance. OK, it's a tech. demonstrator but it does work. It's based on a self-launching glider which has the option of Lithium cells in the wings and an electric propulsion system.

This may be a stupid question, but if we do end up flying battery powered aircraft, will we be able to rely on the "fuel gauge".

I'd say "yes", much more than we do now. When you think how inaccurate/unreliable fuel gauges are on most GA aircraft (I don't trust 'em) and compare that to a battery pack where each individual cell is monitored, along with the environmental conditions... The control unit knows exactly how much charge has gone in and out, what the efficiency of the battery is at various temperatures, how it degrades with time & cycles, etc. Not to mention the voltage gives a bit of a clue when running low.

Something like this, perhaps?

[AdamFrisch]

There will obviously be a separate backup battery that can get you out of trouble, pretty much like the VFR and IFR reserves we have to contend with today in fuel. I think that will also be placed completely away from the main battery in the aircraft, should a fire or something catastrophic happen to the main. At least that's how I'd design it.

And look at this - a hybrid 737-800?

Flying Hybrids! - Technologue - Editorial - Motor Trend

As a complete side - just read that Toyota has sold more than 1 million copies of the Prius now. That's a huge success by any standard. Does anyone really think that any all fossil fuel driven vehicle, be it car or aircraft or boat, has any long term future?

[worrab]

Does anyone really think that any all fossil fuel driven vehicle, be it car or aircraft or boat, has any long term future?

... or to put it another way: Does anyone really think that any fossil fuel has any long term future?

Small planet, finite resources. We really should be grown-up enough to save our resources for the future, investing them in real green energy instead of the smoke 'n' mirrors that are being demonstrated at the moment. The Pious saves a few mpg around town, but the energy cost to build it is substantial and its touring mpg is slightly worse than would be achieved without lugging the batteries and electric motor(s?) around. Wind turbines take many years to break-even and are proving far more costly (both financially and in energy terms) to maintain than the original sales blurb indicated. Even simple solar hot-water generation takes years to break even in energy terms and at present prices will, in any normal financial measure, recover the initial investment.

There are essentially two possible futures. In one, we now invest the finite resources we have in the best way we can to create a (lower) standard of living that is truly sustainable for the future. In the other, we continue to live out our orgy of consumption, deluding ourselves that science and engineering will make it all OK - until one day we wake up to find a denuded earth can no longer supply our gluttonous desires. Sadly, the first is, I suspect, politically not viable.

[horizon flyer]

21st Centaury predictions

Hi Bookworm, good points 50 ltr/hr would give 600kw/hr 25%. 1/4 = 150kw/hr. The batteries at 3kw/hr/kg with a 90% efficent electric motor at 100lbs inclusive of controler would give 150kws, so the saving in wieght would go in to extra batteries, so range would be similar, have to think of the engine and fuel as one package. Also lower frontal area and cooling drag could give extra range. In descent no power needed, might even do power recovery, with the prop as an air bake driving the motor as a generator.

The battery techonogy to do this is lithium air, similar to the zinc air cells used in hear aids. These are in intense develoment, as the holy grail for electric vehicles. The potential is 5kw/kg, so 3kw/kg would seem feasible
they are already at 2.5kw/kg.

IBM, St Andrews uni, the Japanes, which looks the best at the moment and several others are working on them. These will come in two versions, rechargable and for fast charge, cassett replacement of the Lithim and electrolite, which will be reprocessed back into a charged cassetts, so making it a fuel cell based on lithium. Plenty of the stuff in the world

I wish everyone would do the sums and look at the technical problems with hydrogen. Its a total waste of money, time, resources and energy, only 12.5% efficent from energy source to wheel or prop, very difficult to store and insufficent resources of clean fresh water and platinum in the world , in the US it would double the clean water requirment. Also as water vapour, is a global warming gas, the exhaust from cells would make it worse. I have researched this, so don't flame me.

These batteries will be the tipping point for most vehicles to go pure electric drive, like the Chevey Volt, due out this year using LiFePo4 batteries, safer than Li-ion as per burning laptops and restrictions on air travel. An Li air would mean Chevey could leave the IC engine/generator range extender out and add a few more batteries to match the range or better of an ICE car.

Also a different method of fusion power is being researched that looks good, called pulsed fusion, with hydrogen and boron as the fuel. This gives very very little raditaion and little residual, the exhaust is helium. Minimum size will be 5mega watts and about the size of a 2 car garage and less than 1/2 million $ each. Only needs about 2kg of fuel a year. Forget magnetic confinement, to difficult. Note the Starship Enterprise impulse engines are based on this concept, in a real space ship they would make a trip to Mars a 2 week run. NASA are researching this.

So I believe the 21st centuary will be electric. Also with new electric refining methods for titanium, it may replace steel and ali in aircraft so Carbon fibre and titanium may become the materials of choice.

With so many things in the pipline and every time the Arabs up the price, it's another nail in the coffin of oil.

[A_Pommie]

Of course you can run a normal IC engine on hydrogen so there is no need to mess around with fuel cells.
The storage issues are being looked at and if solved would allow current engines to be converted to run on it.
I'll leave MMGW to someone else. All I will say is glaciers