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Electric / hybrid aircraft propulsion (merged)

But that is rather off-topic…. sorry Peter.

This is fine … a bit less “everything electric” evangelism would be appreciated by many, from the feedback I get off-forum

As a statistical datapoint, Europe has moved from 300TWh renewable electricity in 1990 to above 900TWh in 2015, with hydro share remaining constant at a tad under 300Twh… so much for “the sun doesn’t shine enough and the wind isn’t dependable”.

Yes, but the other POV on this is that e.g. wind power is “subsidy farming” on a massive scale, and if you implement a big enough subsidy for what is fashionably called “green” power generation i.e. excluding nuclear which is probably the greenest of them all (i.e. implement a big enough transfer of wealth from those who pay the most tax i.e. the “rich” to those who pay the least tax i.e. the “poor”) then you could generate 100% of the world’s electricity requirements using purely photovoltaic panels (together with the universe’s supply of lithium batteries… but I did say “subsidy” so absolutely anything is feasible)

Time to buy some [more] Tesla shares

My view, as Aart says above, is that the picture is not black and while, electric transport makes sense in some (basically low use / packed-city dweller / other low hanging fruit) areas and the rest gets progressively difficult, with streets full of Teslas in 1hr-a-day-commuting areas remaining far into the future.

IMHO Fuji’s BBC article is mostly publicity harvesting, like Bill O’Leary (Ryanair boss) saying he is looking at having standing passengers. Hybrid power trains make the very least sense in applications where continuous high power is needed.

Shoreham EGKA, United Kingdom

Peter, when you state that wind is subsidy farming, you do that fully aware that the bids won since about April of this year in Germany have been subsidy-free, n’est-ce-pas? By the way… do remind me how much does Hinkley farm subsidies amount to? Was it 30bn pounds? Yet “mum” seems to be the word… or maybe you’re just happy to pay twice the subsidies for nuclear than you would for wind?

You do use motorways quite often I believe, yet I do not see that level of anti-subsidy evangelism when it comes to state-sponsored transport infrastructure…

There seeems to be an awful lot of “off-forum feedback” tantalisingly swung above members’ heads like a Damocles sword. Like whenever water molecules ignore Newton’s First Law…

Last Edited by Shorrick_Mk2 at 28 Nov 14:53

Hinkley is ridiculous; I agree. I have no idea and I don’t know anybody who has any idea as to why the govt is doing it that way.

Shoreham EGKA, United Kingdom

My thought would be that hybrid jet/electrical aircraft might help transport aircraft meet all the other requirements that certification demands, more efficiently.

e.g. You could have a single turbofan optimised for efficiency at altitude and electric motors for the climb. If the batteries and electric motors were large enough to cruise slowly for an hour and do a few go-arounds you might be able to make do with one expensive engine rather than two

Perhaps a turbofan could be boosted by an electric motor to avoid compromises in the turbine required to ensure it operates in all regimes of flight.

..and so on. I’m no expert, but I’m fairly certain that meeting requirements such as single-engine performance must reduce efficiency overall.

Peter wrote:

This is fine … a bit less “everything electric” evangelism would be appreciated by many, from the feedback I get off-forum

Really? that’s just too funny. AFAIK we have one single “electric” thread, this one. One has to wonder what drives those who somehow get “offended” by “electric evangelism” to visit this thread over and over, only to be “offended” again and again

IMO this thread shows a rather typical division in a group of people, in the way different persons approaches new stuff. Some have a natural tendency to use first principles when trying to “get” the changes happening, while others only have a capacity to extrapolate the current status quo, at best, and would actually rather have no change at all when given a choice. In a random population it’s probably around 50/50 of both groups. As I have said before, it’s impossible to understand the merits of electric vehicles by simply looking at them as “drop in replacements” of existing fossil fueled vehicles. They only thing they have in common is the function of transportation. In all other aspects they are two very different beasts. They cannot be compared, and one of them will never be a drop in replacement of the other. Yet, this is exactly what all the nay sayers do, when “pointing out” all the “obvious flaws” of electric vehicles, or electric transportation in general.

It really is very simple. Electric vehicles are more efficient, they are cleaner, they accelerate faster, better to drive, much fewer parts, much higher reliability (by an order of magnitude at least). This means they also will be cheaper, much cheaper when the capacity of production gets up to speed, and fast and slow chargers are installed throughout together with smart grids and distributed power production. There is a potential here for increase in efficiency, and cleaner air, of a magnitude our society have never seen, ever. That potential will be unleashed, there is nothing that can stop it. No economy in the world is able to, it will mean instant bankruptcy. It would be like stopping the transition from horses to cars, or the transition from kindles to electric bulbs, from sail ships to steam ships, from steam to diesel, from piston to turbines. No one can stop tides like these, no matter how “stupid” or futile they seem to each individual who has grown too much in love with his horse.

Aviation is probaby an exception, at least it will be a hard nut to crack. The main reason is that certified aviation, at least certified private GA, has pretty much perfected anti-first principles thinking as an art, science and law for so long now that it is utterly in ruin, like an industrial Cuba, only it has no economic muscle, nor will, left to get out of it. Luckily there is non-certified GA, where things work as they should in a free society. There is also the energy density problem that is hard to get past for longer endurance flight, but not all flights are long endurance, past more than say 2 hours.


I’m a big fan of micro generation and lots of it. Germany started out that way but I don’t know how successful it has been. I have 13kwh ( theoretical max) of solar and 6kwh (theoretical max) of wind and in the 7 years I’ve had it the smaller wind turbine has produced also exactly the same as the solar, this is 55N and an island so it’s not surprising. In those 7 years both have produced 147,864kwh up to 5 minutes ago in total. Im not telling you this for any other reason than it is a fact. I received no subsidy whatsoever. I just wanted to see if I could actually be self sufficient in energy and the answer is maybe. Capital cost of both the solar and wind was around £60k. Life of kit 30 years. Cost of a kWh here is £0.16. I’ve made £23658 worth of electric in 7 years. Payback around 20 years. However, the wind turbine has gone up 50% and the solar has dropped 50% in capital cost.
The question is then, how far can you drive a Tesla on 147,864kwh? I have a Tesla 3 on order. I’m 67 so may never see it unless Elon sorts out his battery production issues. Can one of you intelligent guys work this out.
How far can I fly in the Pipistrel Electric plane with my power?
Fact is I run a large house, charge two hybrid electric cars, an electric buggy, two heat-pumps etc. I buy around £1000-£1500 of power from the grid per annum over and above the free stuff ( free to me cause I’ve bought it).
A strange thing has happened on our island recently. Most islanders live in the past. It was always better than now. They hate change. The planning laws here keep houses with small windows and painted walls. We are not famous for change. But, suddenly the Nissan dealership is inundated with ordered for the new Leaf. Here, the average trip is very short, the island is 37 by 10 miles. Even if I drive from home to the airport, 27 miles, realise I’ve forgotten my wife and have to go back that’s 4* 27 miles still less than even the winter range of the Leaf. Two years ago people were not remotely interested, now it’s an avalanche of interest. You can drive round virtually for free in a nice car which is now not too expensive. Wait for the volume to kick in and this electric car/truck/plane/tools is the most disruptive technology of my lifetime. The Government here are scared to death, they are making £28,000,000 per annum from duty on fossil fuels. How will we bridge the loss as electric takes over, they say. Manage the change I say.

EGNS/Garey Airstrip, Isle of Man

STOLman wrote:

The question is then, how far can you drive a Tesla on 147,864kwh?

If the calculations are correct I must be intelligent.

If Tesla Model 3 consumes 15kWh energy per 100 km then:
147 864kWh / (15kWh/100km) = 985 760km = 616 100 miles

If Pipistrel consumes 70knots 16kWh, that is 12.3kWh / 100km
With Pipistrel you would fly:
147 864kWh / (12.3kWh/100km) = 1 202 146km = 751 341 miles

Pipistrel actually consumes less than Tesla Model 3 per 100km. But it has only 17kWh battery:

Last Edited by AirV at 29 Nov 00:19

Thanks for working that out Airv.

So if we assume a Tesla 3 costs the same as a BMW3 series and the Beema does 40mpg (sorry for being in imperial not metric) is it correct to say the following sum applies:

616,100/40*4.4561=68,635 litres of petrol to do that which at £1.2 per litre is £82,362.

Of course nobody does 90,000 miles per year and able to charge every time from your own set up so its a bit meaningless. Interesting though.

EGNS/Garey Airstrip, Isle of Man

Achimha – do you know when the Pipistrelle is likely to be certified?

YPJT, United Arab Emirates
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