OT: Plane fuel

[harry]

He made them up.

[harry]

Drivel. The made liquid fuel from coal.

Nuclear powered aircraft were never built though contemplated.

A stupid idea at best.

[harry]

Only the brain dead think that.

[The Natural Philosopher]

My point is simple: once coal costs more than uranium, even though there is plenty of coal left, we will use uranium.

There's obviously never a time when we will 'run out' of fossil fuels. They will just be too expensive to be useful as fuel.

[JHY]

That is unlikely to happen any century soon with the plane fuel being discussed.

Sure, and with coal it will also be needed as a raw material for so much of chemical industry that it be more valuable for that before it is still used to turn into plane fuel.

[Brian-Gaff]

There are already experimental electric aircraft, but scalin it up is aproblem due to batteries and weight; Brian not g

[Nightjar]

Who claimed it was a liquid fuel? I said it ran on powdered coal. Jet engines will burn almost any fuel that you can feed into the combustion chamber.

I don't recall claiming that they flew on nuclear power, only that they carried a nuclear reactor.

A version that was actually powered by the reactor was ordered in 1951, but never delivered.

There was also a nuclear ram jet engine tested, but leaving a trail of radioactive waste behind it would rather limit its application in civil aircraft:

In the 1950s, everything was going to be nuclear powered, even cars.

[tony sayer]

Makes me wonder that!. Have a look at the following site and scroll pan zoom out to cover Europe during the day then North America..

and then perhaps not so bad!...

A plane like a Boeing 747 uses approximately 1 gallon of fuel (about 4 litres) every second. Over the course of a 10-hour flight, it might burn

36,000 gallons (150,000 litres). According to Boeing's Web site, the 747 burns approximately 5 gallons of fuel per mile (12 litres per kilometre).

This sounds like a tremendously poor miles-per-gallon rating! But consider that a 747 can carry as many as 568 people. Let's call it 500 people to take into account the fact that not all seats on most flights are occupied. A 747 is transporting 500 people 1 mile using 5 gallons of fuel. That means the plane is burning 0.01 gallons per person per mile. In other words, the plane is getting 100 miles per gallon per person!

The typical car gets about 25 miles per gallon, so the 747 is much better than a car carrying one person, and compares favourably even if there are four people in the car. Not bad when you consider that the 747 is flying at 550 miles per hour (900 km/h)!

[The Natural Philosopher]

The whole thing depends on energy density.

IF a lithium air battery can get close to avjet in terms of energy density then electric planes are totally possible.

In terms of range and load carrying.

If not cost...

[The Natural Philosopher]

On 05/08/15 09:15, Nightjar In the 1950s, everything was going to be nuclear powered, even cars.

And by 2050, one way or another almost everything WILL be nuclear powered one way or another.

Because in terms of primary energy its likely to be thr cheapest thing there is.

[The Natural Philosopher]

You simply didn't read the paper I linked to did you?

Given enough cheap energy, you don't need anything more exciting than carbon dioxide and water to make hydrocarbons.

Plants do it all the time.

Carbon fuel as a feedstock for organic chemistry is not a huge use of it, nor is it especially price sensitive.

And it is infinitely recyclable.

[CB]

Do they not have to beat it by a considerable margin? One of the advantages of jet fuel is that the aircraft mass reduces considerably during the flight and in the latter stages of the flight the mass may be close to 50% of the take off mass - burning much less fuel per mile at that stage of flight.

with batteries you still have to carry the dead weight even when they have no energy left in them.

[The Natural Philosopher]

Well actually lithium air batteries get HEAVIER as they discharge,

So great for takeoff, but you land heavy. Not so good for go arounds..

HOWEVER all things considered electric motors and the ancillary drive electronics are generally lighter than the fuel burning equivalent.

So I reckon the total average weight would be the same if the charged energy density was more or less the same as AVJET.

I'm not predicting that we will or wont have all electric aircraft in 50 years. But given a battery approaching the theoretical limits of lithium air technology that is safe reliable and long lived, it is at least

*possible*.

There are quite a few light aircraft powered by battery electric technology already. A trip to the local model shop revealed that no one is using IC engines in model aircraft any more - its almost all electric these days.

[JHY]

Don?t believe that with coal fired power.

But that isn't the only thing that drives stuff like that.

[JHY]

I did actually and noticed it talks about fossil fuel, not just oil as the OP did.

Yes, but coal is going to be cheaper than that for quite a while yet.

But have significant costs involved in using them.

Yet.

Nope, because much of it isn't economically recyclable.

[The Natural Philosopher]

No. with stupidity and emotional politics societies will essentially commit suicide out of fear of change. Its happened before, but they will be ex-societies. The successful ones - India and China, will be more or less all nuclear.

[newshound]

For model aircraft, nothing surprising there given the physics / engineering scale effects. An insect stays in the air on a puff of wind. An elephant can't even jump.

Don't disagree that it would be foolish to write off electric commercial planes on the long timescale.

[JHY]

No it has not since the industrial revolution.

Hasn?t happened since the industrial revolution.

And the west will be too if it comes to that. There's a reason it left India and China for dead.

[The Natural Philosopher]

Oddly enough the scale effect doesnt always work as you would expect.

A model aircraft flies nicely on 100W/lb. So does an airliner.

So the batteries that work on models will work the same on full size. However model planes don't normally carry a payload, or fly for more than an hour.

That's not acceptable for a commercial aircraft.

This is the best battery technology possible. Energy density is comparable to kerosene or gasoline.

BUT its a LONG way from working in a practical commercial sense.

As you know an electric motor is generally a bit lighter than the totality of an IC engine, though jet engines are simple light beasts by and large.

That helps a bit.

[The Natural Philosopher]

Yet ;-)