OT: More National Grid woes

It would be if the system were closesd mass wise. But it isn't.

Lithium : 0.534 g/cm3

Lithium oxide: 2.013 g/cm3

So 4 times as heavy.

Need a whole new set of design criteria and safety regs.

One of the things going for electric veihicles in general is that electric motors are WAY more efficient than fuel ones. There is almost no heat washing out the back (great for stealth!) Evenn my cheap sub £2 can motors could be tickled up to around 70% by judicicious choices of gearing prop and voltage. Wound properly on decent iron with neodymium magnets around 90-95% was not unheard of. And electric motors have the happy charactersistics of working very effeiciently at lowish power - cruise - whilst still being able to deliver take off power at lower efficiencies.

Or you can simply have extra motors fopr takeoff and switch off a couple, for cruise, if you can afford to carry the extra weight.

So you need less battery energy than fuel energy.

All this is of course part of the design proicess one gioes through to design and build an electric plane. Which I have done many times

In the end the sole issue is that battery. Carefully flown a model plane will do about 1 hour tops on a lithium battery.

The maths of flight shows that those results broadly scale with the plane size. That is, apart from slightly better aerodynamic efficiency due to higher reynolds numbers, the energy/weight/duration equations are identical for all aircraft sizes.

I was amused to discover that a piper cub flies at around 75W/lb takeoff power, which is pretty much what I designed my more sedate models to have.

It's not far off a modern airliner either, thiugh its hard to say what 'horsepower' a jet engine produces.

And that e.g. a Hawker Tempest - possibly the most high performance piston engined fighter of WWII was only around 142W/lb.

To go fast, simply have a smaller wing. Less drag. More speed. Especially on landing.

Power is needed for rate of climb. Climbing needs power times rate of climb over weight.

Climbrate = watts per pound, adjusted for units..

Cruise power is whatever is needed to overcome the natural sink rate...so the flatter the glide angle and the slower the plane the less power to stay up.

So if you want to stay in the air a long time, fly as slowly as possible.

Fuel per unit distance travelled is nore complicated. There you need to start looking at optimising skin /profile drag as well as parasitic drag. That leads to high altitude high speed subsonic flight ...

I normally take note of what you say but on this occasion you are quite wrong. Max Take Off Weight exceeds Max Landing Weight - the plane would both collapse and not be able stop in time if landing at MTOW.

Woe?

Really?

The reality:

Easyjet will apply for a connection agreement for their expected maximum demand, leading to construction of a connection either on the distribution or transmission network. Easyjet will wholly pay for that connection.

If additional transmission or distribution infrastructure is required then the transmission operator or distributon network operator can fully recover the costs of building those assets.. The transmission and distribution network operators earn revenue from managing those capital assets for decades to come, a larger asset base means more income

The upshot is Easyjet pays for their connection and contracts with their chosen energy supplier for supply.

Generation assets will be built if required to meet that demand

The transmission operator and distribution network operator transfer more energy and improve utilisation of their assets and will earn money from this activity. The costs of utilisation of the connection by Easyjet will lead to an income stream for the transmission and distribution network operators.

What is clear is there is absolutely no 'woe' for National Grid.

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Utter bollocks

Several aircraft have zero ability to dump fuel like the B737, the B757 and the A320

Utter bollocks again

The sole limitation is structural and if an aircraft needs to urgently land overweight it will, regardless of fuel state. Runway length when overweight may be an issue but it's far better to be on the ground with a knackered airframe or more likely with landing gear that needs inspection than almost anything else.

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And you believe that Easyjet has the cash to do this? Then, the truth is that Easyjet will be slipstreaming Santa's sleigh having contracted his team for year round operations which makes great sense as having those reindeer idle for 364 days on full pay is folly.

Electric passenger JETS. What sort of jet plane is this? There would have to be propellors. And the battery technology is not even on the horizon.

FAKE NEWS.

What Easyjet, a poblic limited company can or cannot afford is of absoltely no concern to anyone but the company itself and their bondholders and shareholders. All I was stating is that companies or individuals requiring a connection agreement and ongoing energy supply cause no 'woe' for Transmission or Distribution Network Operators, it's exactly the opposite.

Well exactly. Te orioginal thread was not about electric planes, but about IIRC electric cars and the upgrades needed to replace all fuel cars with electrivc cars which WOULD have required serious grid upgrades.

Which would happen as you decsribe above admittedly, but not overnight

Cmon guys. We all know this is just PR virtue signalling by easyjet.

No one expects it to actually happen

Bollocks, you seem to have snipped the line about long haul flights.

Bollocks - that was not in my posts

If it has to land it has to land. If it can dump fuel or if it can circle for a few hours to burn off fuel it will.

For a more complete understanding of this and not including the word bollocks please read the post from Pihero

It might help you if you realised my response was NOT to you but to TNP

All my points ARE valid, the word bollocks was an entirely appropriate response

Some long haul flights are performed using aircraft without any fuel dump capability, for instance BA from LCY to JFK, operated by an A318, over 3000nm over a very big bit of water.

The B757 is used on numerous long haul charters flying the North Atlantic, an aircraft without any fuel dump capability whatsoever, but also one which can land at its max takeoff weight with zero impact on the airframe or landing gear. There have been many cases of aircraft catching fire in flight, or losing two out of three hydraulic systems or some other major malfunction, some with passengers onboard some with just cargo. Getting on the ground as quickly as possible has proven to be the key to survival for the humans onboard again and again. That the airframe might never fly again is immaterial. Flying round in circles burning off fuel or dumping it is only used for significanly less urgent 'emergencies'

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These are not any old jets, these are ducted fans. There are plenty of different battery technologies in the labs at the moment which would be emminently suitable. Practicality on a commercial scale is another question.

Ultimatly 1g of matter yields 25GWh of energy, enough to run an electric vehicle for 4 million miles without refuelling.

See also

A jet engine is something containing a gas turbine. You last comment is entirely irrelevent.

Not with a pulse jet or ram jet :)

SteveW

Is it?

Exactly.

It's probably unhelpull to call electric ducted fans jets, but a turbofan enfgine as used in nearly all commercial jet aircraft is in fact a gas turbine driven ducted fan.

And turboprops are just larger unducted fans.

(It so happens that accelerating a large mass of air a little is a better and more efficient way to get power than accelerating a small mass a lot.)

So callinf EDFs 'jets' is no worse than calling turbofans 'jets'