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The largest electric aircraft just flew [video]

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Re: The largest electric aircraft just flew [video]

#321

Post by frollogaston »

alberth wrote: post #83

Is this EV or Hybrid? The founder seems to sneak in the word "hybrid", around 1m30 mark in the video below. https://youtu.be/nM86DBOqgPM?si=5unXLmPxk6M_kmuN&t=86 Note: not being negative, I just want to ensure I understand correctly since the title might imply something else. Update: confirmed, it does use aviation fuel. > "The airplane will also include a reserve-hybrid configuration, consisting of two turbo generat…

Why do the generators specifically need aviation fuel? They aren't the actual motors.

Re: The largest electric aircraft just flew [video]

#322

Post by insanetake »

fmpfmp wrote: post #237
class3shock wrote: post #155

Doing some math. Regional jets get somewhere around 45.9 seat miles per gallon (1). So 30 seats, going 125 miles would take around 80 gallons of jet fuel. This is likely low because all the jets listed are bigger and likely flying longer flights that are more efficient but just go with it. Jet fuel has a specific energy of 12 kwh/kg and a density of 6.7 lb/gal (2). So 80 gallons of jet fuel is 536 lb, or 243 kg, and…

Also consider that an empty battery weighs the same as a charged one. Whereas empty fuel tanks don't. I wonder how annoying this is for the engineers to stay within landing weight limits (MLW)

> an empty battery weighs the same as a charged one

Technically, an empty battery weighs less than a charged one.

In practice, the difference is negligible.

Re: The largest electric aircraft just flew [video]

#323

Post by [deleted] »

luma wrote: post #87
alberth wrote: post #83

Is this EV or Hybrid? The founder seems to sneak in the word "hybrid", around 1m30 mark in the video below. https://youtu.be/nM86DBOqgPM?si=5unXLmPxk6M_kmuN&t=86 Note: not being negative, I just want to ensure I understand correctly since the title might imply something else. Update: confirmed, it does use aviation fuel. > "The airplane will also include a reserve-hybrid configuration, consisting of two turbo generat…

Hybrid after the first 125 miles, total range 500 miles. Their problem is diversions - an incident at the destination airport may mean an passenger aircraft may need to land at an airport which could be a couple hundred miles away. The hybrid powerplant throws the fuel efficiency numbers off so goal is not to run it unless needed, but they could not get certification without it.

[deleted]

Re: The largest electric aircraft just flew [video]

#324

Post by frollogaston »

_heimdall wrote: post #152
dyauspitr wrote: post #145

Earlier quoted context omitted.

It uses aviation fuel only after the electric battery is empty. And uses the fuel to run generators, the motors are all electric.

Its hard to call that the largest electric aircraft IMO. It's electric until it can't, then its not.

You can't dip into emergency fuel for non-emergencies, cause then you could have a real emergency. It's not like a hybrid car that people could run completely on gasoline. So sounds like this plane would be electric almost all the time.

Re: The largest electric aircraft just flew [video]

#325

Post by frollogaston »

disillusioned wrote: post #192
_heimdall wrote: post #152

Earlier quoted context omitted.

Its hard to call that the largest electric aircraft IMO. It's electric until it can't, then its not.

Well, technically, it's always electric. Sometimes the source of that electricity is from the battery system, and sometimes it's from an onboard generator.

Nah, electric means battery

Re: The largest electric aircraft just flew [video]

#326

Post by frollogaston »

arjie wrote: post #122
bryanlarsen wrote: post #105

Earlier quoted context omitted.

According to the video, 2/3rds of that range is for loiter and divert capability. It's illegal to fly a route without the capability to loiter and divert. You need 30-60 minutes of loiter + 100 miles of divert. This plane cannot be used on any route longer than about ~200 miles. Which can be driven in 2 hours, although obviously the OP was referring to the 120 mile electric range.

> This plane cannot be used on any route longer than about ~200 miles. Which can be driven in 2 hours. Huh, perhaps then it wouldn’t be suited to places where people drive at that speed. In the US I doubt people drive 200 miles routinely in 2 hours. It would be closer to 3.5 h I think going by the routine 6 h it takes SF to LA which is about 350 mi. I think if you have very high speed road/rail transportation that do…

Probably half the people in this thread imagine LAX to SFO vs taking the 5 when thinking about long trips.

Re: The largest electric aircraft just flew [video]

#327

Post by IAmBroom »

enquirewithin wrote: post #166
waterTanuki wrote: post #107

Earlier quoted context omitted.

It's clearly marketed for remote communities with little to no connecting infrastructure. Think Alaskan wilderness or Hawaiian island hopping. This isn't for getting from LA to Denver for skiing.

An aircraft like this can be used two or three times a day, while spending the rest of the time charging. A piston or turbine powered aircraft can run all day.

Making the battery replaceable by heavy equipment would drop the turnaround time for these. The planes fly regular routes (mostly), and could store a few extra batteries at their regular destinations.

Odd added benefit: the potential ability to jettison a huge part of the weight in extreme emergencies to increase flying time by the backup ICE system.

Re: The largest electric aircraft just flew [video]

#328

Post by IAmBroom »

walrus01 wrote: post #159

The interesting part to me is that a lot of current electric aircraft development seems to be waiting for battery technology to catch up. They're far ahead in terms of the motors, propeller, electric propulsion control system. The limitation is the battery capacity. Companies like Joby, Archer and others also seem to be taking the huge gamble that battery density in Watt-hours per kilogram will SIGNIFICANTLY increase…

As noted elsewhere in this thread: probably ain't gonna happen. Battery energy density increases are tapering off. We may already be close to the maximum possible (where close means within a factor of 2 or so).

Re: The largest electric aircraft just flew [video]

#329

Post by IAmBroom »

sandreas wrote: post #165

I wonder if these airplanes are using helium to "reduce the weight"... that is something I also don't usually on drones. Probably too expensive.

Helium only reduces the weight proportional to the volume it occupies - which is why dirigibles look like big balloons.

Filling a wing with helium would barely shift the weight of the plane measurably. Filling the cabin and cockpit would be bad for what I hope are obvious reasons...

Re: The largest electric aircraft just flew [video]

#330

Post by IAmBroom »

boelboel wrote: post #235
pkulak wrote: post #98

Earlier quoted context omitted.

> Many places don't have the demand or physical possibility for a railway. This I don't get. I've seen rail stops in the smallest towns, where the train stops for 30 seconds to let a couple people on or off. Places where even the smallest airplane makes no sense at all. Not 30-100, 1-2.

Old lines which have some more riders on other stops I imagine. You only need to maintain the rail which has been laid 150+ years ago.

I work in rail, in the US. This is not true. The FRA mandated a massive upgrade to rail safety for passenger rail about a decade ago, pushed by Congress, and it's still filtering through (though mostly achieved).

That being said... federally supported rail is still far more economical than flight. It almost has to be: the train doesn't need to lift off the ground.

(Why is it in Star Wars' universe that every 2-bit peasant owns permanently levitating "cars", but can't afford adequate lighting in their hovel?)

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