Peter wrote:
Actually this was at one point a hoped-for market for small gas turbines; they would run at optimum efficiency and only when needed.
Only that there is no “optimum efficiency” of small gas turbines that even comes close to the efficiency of a piston engine and the weight/size advantage of a gas turbine is less relevant in cars than it is in aircraft.
Peter wrote:
But this is not relevant to aviation because the extra weight is pointless; if you need the engine to be big enough to generate enough electricity for enroute flight, you may as well use it to drive the propeller and forget all the electrical stuff
Not quite. First of all you need much less output for enroute flight than for takeoff so you can size your ICE for enroute only and secondly, you gain flexibility in how you layout the plane. The ICE can sit anywhere and the small electric motors and cables can go anywhere you want them.
Airbus and others are betting on this approach. I am sure this is where the industry is going.
I would not say “much less output”.
Climb is 100% power and cruise is perhaps 65% power for a reasonable compromise MPG. That leaves little to play with. It is a lot of technology and a lot of gear just trying to get something edible out of that 35%.
Obviously if you build a plane which can fly with say 30% power that’s different, but then you could build the same plane with an avgas engine. It is called a motor glider 
They do sell, but in relatively tiny numbers, due to many tradeoffs. In the car world, it’s a bit like the Toyota Pious which delivers better MPG due to
A Pious with a petrol engine would probably do almost the same MPG…
It’s basically goalpost-moving.
achimha wrote:
Airbus and others are betting on this approach. I am sure this is where the industry is going.
Electric fans driven by an oversized APU with batteries to provide additional power for take-off? Interesting idea and why not?
Peter wrote:
I would not say “much less output”.
In a twin it is 200% of what you need for “still climb a little bit”. Opens a lot of opportunity for a serial hybrid electric setup.
Peter wrote:
It’s basically goalpost-moving.
Yes, goalposts move all the time. The apple to apple comparison that are being made here all the time is not what counts because the world is changing, habits change, preferences change. A large percentage of today’s youth is not interested in obtaining a driver’s license in the metropolitan areas of Europe. It used to be the single most important thing in the life of a teenager.
LeSving is very much right in saying that the long distance IFR tourer market is a very very small niche. I would estimate that > 75% of the airplanes at my airport have not left the country once in the last 5 years. There are a lot of uses for airplanes that don’t allow you to fly for 7 hours against a 50kt headwind from Croatia to the UK 
It is the same with cars, I have switched exclusively to all electric because I would not even think about driving for 9h e.g. from Germany to Italy for holiday in a car like the whole country used to when I was a kid. I am by far not alone so clearly goalposts have moved.
achimha wrote:
I have switched exclusively to all electric because I would not even think about driving for 9h e.g. from Germany to Italy for holiday in a car like the whole country used to when I was a kid. I am by far not alone so clearly goalposts have moved.
I wish that would happen faster… Lower traffic density would be great, for those of us who ship vehicles across the world and store them locally for specifically that purpose! Mostly its motorcycles but a friend has an Alfa that’s been living in Germany for a couple of years and has been everywhere from Wales to Italy. It’ll come home in the Autumn. My motorcycle has been from Dubrovnik and Bari (south) to Scotland (north), Spain (west), to Eastern Europe, and to many of the Mediterranean islands.
I’d love to similarly fly a Luscombe or whatever around Europe, meeting people along the way without radio, flight plan, airport or customs hassles. That would be so much fun. But it’s been made impractical and is being kept impractical for no good reason, while the masses on the ground are gently coerced back into limited scope cars and mass transit holidays, just as you’ve described.
Don’t cheer too soon Silvaire because I will be driving all across the continent once I get a self driving car that really works, has a good office and sleeping setup inside and good 4G/5G coverage everywhere.
And even that will become reality much sooner than most people think.
achimha wrote:
I will be driving all across the continent once I get a self driving car that really works, has a good office and sleeping setup inside and good 4G/5G coverage everywhere
Great. Enjoy the drive (sleep?) and we’ll see you out there.
Silvaire wrote:
without radio, flight plan, airport or customs hassles
Try flying, driving, swimming, walking, whatever as a foreigner into the land called USA. You need visa up front, scrutinized digitally by the CIA on your “background” etc etc. It’s less hassle getting into China. Customs hassle within countries in Europe is walk in the park in comparison, at most borders you have no idea you have crossed them, with the exception of the UK maybe. Europe consists of different countries, if you didn’t know, and it will stay like that for all foreseeable future.
Keep this thread on topic otherwise I will move posts into the off topic / politics thread.
What if it’s cloudy? What if the wind doesn’t blow? It seems that in spite of these (oft not so well-founded) fears, California is well on track to beat its target of 50% renewable electricity by 2030 (in spite of assurances to the contrary put forth on this board couple years ago).
