aart wrote:
Maybe Airborne_Again could talk to his fellow professors there and enlighten us a bit more what they see happening on the aviation front..
Sorry, I’m in Uppsala, not Gothenburg (Chalmers). OTOH, we have world-leading battery research in Uppsala as well, but more basic research.
With wind or tidal electricity production, and islands having excellent raw material availability (dihydrogen monoxide), the only remaining problems will be accident safety. And disposal of the oxygen waste product at the fuel facility? :-)
dihydrogen monoxide
I often wonder how many people get that one 
From above:
A first flight of the demonstrator aircraft is still envisaged in 2022, with CAeS currently negotiating to acquire an Islander for the effort. Providing there are no hiccups, entry into service is envisaged in late 2023 or early 2024, says Hutton.
In addition, Jenny Kavanagh, chief strategy officer at CAeS, says operators were also keen to retain other characteristics of the Islander, such as short-field performance and its nine-passenger capacity.
They must have access to interesting sources of funding given that they can’t afford to buy a knackered old Islander but can afford a “chief strategy officer”
Not only a Chief, but how about the indians below her?
Pipistrel is going somewhere with their electric machines. 111 delivered last year, more than their gas-powered aircraft.
See page 9, and 31.
https://www.yumpu.com/en/document/read/65283638/eflightjournal-04-2020-01-2021double-issue
Widerøe looks to be going forward with Tecnam and RR for the electric/hybrid P2012. 2026 they say, but lots can happen in 5 years.
https://www.rolls-royce.com/media/press-releases/2021/11-03-2021-rr-and-tecnam-join-forces
From here
dublinpilot wrote:
So we need to be looking to the future for a more sustainable future.
The thing is, most light aircraft are already incredibly limited by the weight of the fuel they need to carry in order to have a useful range.
This fuel is generally gasoline, which yields approximately 13,000 watt hours per kg.
The batteries in a Tesla car yield about 255 watt hours per kg.
No amount of wishful thinking is going to make that add up to a useable product. What does your W&B calculation look like if you suddenly have to assume a fuel weight of 40 times what it was (and that’s being generous), even if you get to remove 150kg of engine in the process?
It may exist, but a two-seat ultralight with 50 minutes endurance is not a useable product for anything more than going round in circles for the fun of it. There is a tendency to think that they’re starting with a two-seat ultralight as a proof-of-concept and something much more capable is not far away, but the reality is that the ultralight is the largest electric aircraft that can realistically be created unless someone solves that fundamental energy density problem.
Graham wrote:
This fuel is generally gasoline, which yields approximately 13,000 watt hours per kg.The batteries in a Tesla car yield about 255 watt hours per kg.
That is a biassed comparison for 2 reasons:
1. Efficiency to convert these Wh into thrust is very different for electric motors and internal combustion engines.
2. You safe a lot of weight on the engine – so you could even say “I fly electrically for 30 Minutes at the same weight before you even can get a single drop of fuel into your tank”.
That’s true, but the extent to which it is true depends very much on whether the electricity comes from nuclear fusion, or from burning coal and dumping the acid rain into the country to the east of you
The difference in weight is debatable because any electric plane which is actually usable for going anywhere will be loaded to the gunwales with batteries. Just like our current ones are loaded with fuel. So the ~100kg saved between a 250HP 3 phase brushless motor (with a load of pretty big electronics – see the photos from Aero EDNY showing some “real” implementations) and a 250HP IO540 will just go on batteries to give you just enough range to reach Mali Losinj (from Munich) and taxi up to the charger
It will probably happen but it’s gonna take a long time, because there is no really great battery technology coming along. And no magical solution to generation, transformer sizes (watts per core cross-section at 50Hz), etc. It is beginning to work in cars because
One solution would be 400Hz mains Whoops, that was implemented in aircraft around WW2, I think. I used 400Hz motor-generators to power the pirate radio transmitters I used to build as a teenager.
Graham wrote:
This fuel is generally gasoline, which yields approximately 13,000 watt hours per kg.The batteries in a Tesla car yield about 255 watt hours per kg.
Yes, today. What was the energy density of batteries 10 years ago? 20?
It may exist, but a two-seat ultralight with 50 minutes endurance is not a useable product for anything more than going round in circles for the fun of it. There is a tendency to think that they’re starting with a two-seat ultralight as a proof-of-concept and something much more capable is not far away, but the reality is that the ultralight is the largest electric aircraft that can realistically be created unless someone solves that fundamental energy density problem.
Well. Several people actually involved in aircraft design seem to think that it is possible.
