[bprater]

Batteries are heavy. Teslas are very heavy cars. Aircraft are extraordinary light, compared to ground-based vehicles. Even in flight, large aircraft will burn a lot of their fuel during ascent. Electric powered aircraft get to drag around the heavy used batteries until recharge. And then you have to figure out how to refuel. Until a significant change in battery density, electric planes aren't going to be a thing.

[thebruce87m]

Would you class them as very heavy? Trying to find some figures to compare: https://www.quora.com/Is-a-Tesla-heavier-than-an-ICE-car-of-...

Tesla Model S - Curb weight 4,647 lbs Audi A8 - Curb weight 4,751 lbs BMW 7 series - Curb weight 4,244 - 4,848 lbs

Tesla Model 3 - Curb weight 3,627 to 4,072 lbs Audi A4 - Curb weight 3,450 to 3,627 lbs BMW 3 series - 3,582 to 4,010 lbs

[4death4]

Compare a Bolt (~3700 lbs) to a Fit (~2600 lbs).

[k4rli]

A luxury car usually weighs more due to higher quality materials, larger displacement, more overall modules and wiring. Tesla is an ecobox made with cheap materials so majority of its weight is the battery.

[GauntletWizard]

Sure, when you're comparing them to German tanks, they look pretty normal weight. How about a Kia? The K5 is comparable to a model 3, if not as nice, and it maxes out at 3,534 lbs

[scythe]

>Even in flight, large aircraft will burn a lot of their fuel during ascent.

I've been wondering if this offers any escape. Suppose that you have a power supply from the ground during the initial acceleration, and the final cruising velocity is not much higher. Or just build a huge ramp.

It sounds like a joke at first, but it might not be impossible. You just need some kind of reverse linear induction motor that doesn't require much weight on the plane side. Perhaps the fuselage is the magnet? If the takeoff acceleration is 2g, you need a 1 km ramp. The varying lift of the wings will be an obstacle, though this might be manageable with flaps. Of course, a 2g takeoff would be a dramatic experience for the passengers.

[acoard]

This principle is already in use in "Ski-jump" aircraft carriers[0] like the British and Chinese use, compared to the catapult operated American carriers. The problem is it isn't remotely high enough. It does have an effect on take off distance, so for that short amount would help for fuel efficiency, but then you still have +30,000ft to climb. 737's often cruise at 30-40k feet, as the air is thinner up there so there's less drag and you have better fuel efficiency. Even if you launched airplanes off the tallest structure ever built (Burj Khalifa, 2,700ft), you'd still have the majority of the climb ahead of you. Planes go high.

My non-credible idea would be to just use an Apple-style magsafe charger on the back of the airplane that disconnects midair at 30,000ft and falls on the helpless people below.

[0] https://en.wikipedia.org/wiki/Ski-jump_(aviation)

[Manuel_D]

It's not takeoff that consumes a lot of fuel, it's climbing to cruising altitude. You're not going to get much savings with a launch catapult. A catapult really only helps with shortening the runway distances required to take off (e.g. off an aircraft carrier).

[kirrent]

If you're going to try and get an aircraft to cruising altitude without using its own energy, surely the easiest concept is with a tug aircraft towing to altitude. Hell, there's even fairly speculative concepts like Magpie envisaging a series of tows.

[matt_heimer]

So if I understand correctly you'd like to shoot planes into the sky with a giant railgun?

[ramesh31]

>Until a significant change in battery density, electric planes aren't going to be a thing.

There's a big caveat there though. Current aircraft engines are extremely expensive to operate and maintain, regardless of fuel costs. Even a simple GA piston engine would cost more to operate than a small commercial EV aircraft's motors. Replacing turbines with electric motors will provide cost savings that actually make small commuter flights economical again. Kerosene and jet engines aren't going anywhere for the long haul flights. But the future for electric aviation is in the sub 300 mile regional commuter market, where it's faster than a train and has the simplicity of catching a bus.

See Eviation Alice for an example: https://www.popularmechanics.com/flight/a41453056/eviation-e...

Today's battery tech is just barely good enough at this point to start becoming useful for these kinds of flight profiles.

[bluGill]

Sub 300 miles the train should be faster door to door. Trains a better able to get into the middle of a city - airports both take a lot of space and are noisy so they get pushed to the edge of the city. Trains are also better able to integrate with a public transport system so they are easy to get to. Trains don't have the silly security lines (normally - though planes don't need them either). Trains also don't have large economic benefits from every seat full, so they can better handle someone making a last minute decision to go.

Note that I said should above. The reality is North America has terrible train service, and management (congress!) doesn't care: so airplanes end up better despite all reasons they are worse for short trips.

[ToucanLoucan]

I struggle to conceive of a green future for aviation. I'm not saying we can't have planes, we absolutely should and for many applications they are the only answer: but high speed rail could offer a lot of what airlines currently do at significantly lower cost to both passengers and to the environment, and with less need for such extensive and radical safety features as are required for aircraft.

But just like, reading this comments about everything from batteries to from-ground power sources for ascent to dragging dead batteries after use... like, what if we just flew less? Yes for international travel that needs to happen at speed, a plane is basically the best option. But for... basically everything else, what if we just sacrificed some convenience to not be dumping industrial amounts of waste into the atmosphere?

I'm reminded of how much air quality improved almost worldwide when covid first hit and offices were shut down, offices that, I remind you, continued to function largely just fine after a period of adjustment to remote work. I'm obviously extremely for making all transportation tech more efficient, but an under-discussed element I feel in this is just... doing less shit? Moving fewer people when moving said people isn't really needed? Maybe not growing all the pineapple in one country and shipping it over to a different country to be packaged in plastic and then shipping those all over the world so everyone on the planet has ready access to pineapple, a ton of which is just going to go straight in the garbage because we don't actually need all that damn pineapple?

[hef19898]

Where do you confidently take the idea from, that electro motors for electric aircraft are cheaper to maintain than piston engines?