[semi-extrinsic]

I'm not saying it's impossible to make a 5, 10, 15 seater all-electric work. I'm saying a 100 passenger all-electric will never fly without a revolution in battery tech.

You say "just increase mass of the vehicle which is battery". If you read about this airplane you find that since they are using batteries with an appropriate safety rating for aviation, they've used all the space and mass already:

"this eBeaver isn’t carrying passengers — there isn’t room — and will only have a 15-minute endurance with a 25-minute reserve."

https://www.skiesmag.com/news/harbour-air-makes-history-with...

I tried finding concrete info about the Eviation Alice, but the best I could find was a photo of an unpowered full-scale model. They've been saying the first flight test is a couple of months away for more than one year it seems.

[dmix]

I’m curious if there is some monetary trade off for the sound level:

>> the plane’s four-bladed Hartzell composite propeller generated all of the remarkably quiet takeoff sound — a fraction of the thunder from the legacy Beaver’s radial piston

Maybe they’ll get a special class to be able to launch closer to cities without the noise complaints. Although I’d imagine it’s still pretty loud.

Also the bit after the paragraph about the batteries filling up the back mentions they didn’t use fully efficient batteries... they purposefully chose very safe but underpowered batteries previously used and flight tested by NASA for their own testing purposes instead of the higher end batteries used today in EV cars.

[tim333]

>I'm saying a 100 passenger all-electric will never fly without a revolution in battery tech.

I don't think you're right from an engineering point of view. Just multiply the aircraft size and battery number by some amount. For example:

>In September 2017, U.K. budget carrier EasyJet announced it was developing with Wright Electric an electric 180-seater aircraft to be developed by 2027. https://www.nextbigfuture.com/2018/09/easyjet-and-wright-ele...

Though all battery aircraft whether micro drones or A380 size will have a limited time they can stay up. Electrics currently seem limited to an hour or so whereas jets can do 16 hours now.

There seems quite a lot of potential on short routes <300 miles though using present batteries. (eg. London Paris or LA San Diego).

[leoedin]

There's a lot of mistruth in green technology. You need to get to first principles - the numbers. Look at the power requirements and weight budgets of large airliners, look at the best case energy density of lithium batteries and do the calculations yourself. That's what the parent comment did.

[Robotbeat]

They're using an existing certified battery for the prototype, not for operations. It takes time to certify battery chemistries.

And small general aviation aircraft like these usually only have a small portion of their takeoff weight as fuel, maybe 20-25%. But passenger aircraft may have 50% of their takeoff weight be fuel (for instance, 777 on long haul flights). Electric aircraft like Eviation will need to go further (55%). This is something you can do with a cleansheet design like Alice, but can't with a mere conversion designed literally over 70 years with manufacturing and materials from 70 years ago.

And you can apply the same principle of increasing take-off weight fraction for kerosene-powered aircraft as well. The Virgin GlobalFlyer was 82% fuel on takeoff. It flew around the world and then some. Kerosene is much better than it needs to be to enable modern flight.

You're absolutely right about Alice being late, but the design concept is a good example of what is possible. You combine state of the art but existing lithium ion chemistry (which needs some work for aviation certification but IS used on the ground already) with state of the art lift to drag ratio (and perhaps additional innovations, like wingtip propulsion to reduce losses from wingtip vortices) with efficient enough structural mass to enable 55% of the takeoff weight (as well as landing weight, of course) to be battery.

These things multiply together to enable long range.