Electric Planes - A Pipe Dream?

[Khandro]

How on earth do they think they can generate sufficient energy to fly a passenger plane? I notice, which can't help but raise a smile "The company is currently seeking to improve its batteries " !

http://www.itv.com/news/2017-09-27/easyjet-hopes-to-fly-electric-planes-within-a-decade/

[mikey4444]

Yes....completely !

[jim360]

From such dreams come wonderful inventions. I agree it seems tricky to envisage at the moment, but who knows?

[TheChair]

I can remember someone posting on here a few years back that electric cars would never be feasible because of the weight of Lead-Acid batteries. Later that same year, Tesla released their car based on Lithium cells.

[Khandro]

'First, let's figure out how much power does a 747 needs to takeoff:
Assume:
Engine thrust = 284 kN Takeoff speed = 170 knots
Takeoff power = 90% max power

Using P=Fv
, converting the variables to SI units, we get
Power=88,948,800W
Or, in other words, around 90MW'

That's just to get off the ground

The Chair, Those Tesla figures are are a bit misleading, they claim a range of 120 miles but that's with new batteries (£5,000 each)older Teslas are getting much less and cars developed in California where the sun always shines will not stand up to the British winters, try heating them from the battery and see what effect it has on the range

[Khandro]

'Let us take this a step further and evaluate the total energy needed for a flight. Assume all required energy comes from onboard energy storage (i.e. no solar panels / windmills). Let's also assume a full power climb to cruise altitude of 15 minutes, 50% power cruise for 4 hours, and a completely idle descent which does not consume any power at all.

Using E=∫Pdt
, we get the total energy needed for a flight is
720,485,280,000J

.

With that amount of energy, you can pull a 735 kiloton object up 100m. If all those weights are water, that's close to 300 Olympic swimming pools.

If you power the whole plane with batteries, you'd need 47 million AA batteries.'

I don't vouch for the stats, I just quote them :0) What do you say jim?

[jim360]

I'd say that it's a stupid thing to propose if it's demonstrably unrealistic using High-School physics.

[RATTER15]

So easyjet and the manufacturers have it wrong. Maybe you should let them know Khandro, Im sure they would greatly appreciate your mathematical conclusions! ;-)

[douglas9401]

Jet packs, hover boots and food pills. It's the future I tells ya!

[Togo]

If you take the "right" pill Douglas, you don't feel the need for jet packs and hover boots.

[Huderon]

It may not be that big a pipe dream. NASA have a project called Sceptor which, if I read the piece correctly, aims to have a battery powered 9 seater by 2019. The S in Sceptor stands for scalable so one never knows.

https://www.nasa.gov/centers/armstrong/features/sceptor.html

[Togo]

Who knows?

https://www.msn.com/en-gb/money/technology/easyjet-could-be-flying-electric-planes-within-10-years-as-boffins-start-development-on-battery-powered-aircraft/ar-AAsvOUc?li=BBx1bGE

[murraymints]

I aint getting on one !

[Tilly2]

It would be fantastic if they could do it, wouldn't it?

[New Judge]

Why?

Modern jet engines are very efficient and produce no more in the way of pollution than generating the required amount of electricity would (assuming that aircraft want to fly most of the time and not just when the wind is blowing or the sun is shining).

[ludwig]

It will all become obsolete once we've perfected a reliable teleportation device. The main thing is to ensure there are no flies in the room.

[Khandro]

NJ. It would be easy if one had a long dangling lead to an electric source on the ground, but an aircraft would need to store it's electricity on board in the form of batteries. Everyone keeps hoping for a major breakthrough but considering battery powered vehicles have been around since the 18 hundreds it really isn't happening.

What is worrying is that governments are starting to formulate legislation for the future, on the assumption the science will find an answer.

[ludwig]

// It would be easy if one had a long dangling lead to an electric source on the ground, but an aircraft would need to store it's electricity on board in the form of batteries. //

This could be solved by having a normal plane flying close behind the electric one carrying it's batteries. A relatively short lead could then be used.

[vulcan42]

I find this ironic considering airlines refuse to carry batteries because of the fire risk. The "improvements" required must be quite substantial.

[New Judge]

"What is worrying is that governments are starting to formulate legislation for the future, on the assumption the science will find an answer."

Quite agree, Khandro. They've started with cars in the hope that battery technology (and charging infrastructure) will be available by 2040. What's next? Only electric aircraft by 2045?

Large battery technology has not shown any great strides forward. I'm still carting round a cubic foot of lead and acid under my car's bonnet which is necessary just to start the thing up. There has been no appreciable difference in that contraption since I bought my first car (many) years ago.

[Spicerack]

Surely your first car had a handle, judge?