6 ms·

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

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.

ramesh31 3y ago
>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-electric-aircraft/ 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 3y ago
  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.
  - majormajor 3y ago
    It's hard for me to imagine (in the US) the government allowing an explosion in small commercial flights w/o TSA and all that rigamarole. If you get 10x, 100x the volume today, with a less upper-crust passenger base, the perceived security/terrorism risk probably starts getting talked about.
    - JakeTheAndroid 3y ago
      and there is already a massive shortage of ATC employees right now. At minimum this would need to be addressed and more than double the workforce of ATC. That's without accounting for any additional infra that might be needed to support a 10x or 100x in traffic.
      - ramesh31 3y ago
        >That's without accounting for any additional infra that might be needed to support a 10x or 100x in traffic. The TSA requirement is nil for 10 person flights and these would be VFR only anyways. You would avoid a vast majority of the need for added ATC by operating between uncontrolled fields and relying on enhanced automation. The traditional airport model doesn't really apply when flights can be made so casually. Imagine a world where tiny runways that only service EVs are integrated into the city and you can hop between them as easily as catching a bus. Crosscountry travel would be also be possible via smaller hops, and cost less than a direct long haul jet liner ticket. All of that is enabled by the orders of magnitude reduction in operating costs. EV Alice is claiming $200/hr to operate an aircraft that has the equivalent performance to a $1k+/hr turbine within the range limitation.
        JakeTheAndroid 3y ago
        > Imagine a world where tiny runways that only service EVs are integrated into the city and you can hop between them as easily as catching a bus. I mean, that sounds like a massive shift in infrastructure and city planning. I am not sure how efficient and affordable this would need to be to achieve that level of integration into daily society. Currently nothing, in the US at least, is setup to function this way. Whereas rail and roads are already deployed. And again, this ignores any of the issues brought on by scale. If this is the way we want people traveling at a 10x or 100x rate, the airspace is going to be busier and likely will need some sort of coordination, whether ATC or some other mechanism.
- ToucanLoucan 3y ago
  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 3y ago
  Where do you confidently take the idea from, that electro motors for electric aircraft are cheaper to maintain than piston engines?
  - deleted 3y ago
    [deleted]
scythe 3y ago
>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.
- Manuel_D 3y ago
  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).
  - Sohcahtoa82 3y ago
    You just need a fast enough catapult mounted on a slope. ;-) An object dropped at 30,000 feet would be traveling at about 3,000 mph when it impacted the earth, ignoring the atmosphere. Maybe launch at 4,000 mph to overcome drag to throw something into cruising altitude? We'll just wear some noise canceling headphones to block out the OVERSPEED alarms.
    - Arelius 3y ago
      I mean, isn't ignoring the atmosphere ignoring like 90% of the domain?
    - bhandziuk 3y ago
      Just for perspective this is about mach 5. But I guess there is no speed of sound if you're ignoring the atmosphere :)
    - Night_Thastus 3y ago
thebruce87m 3y ago
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-equal-size 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
- GauntletWizard 3y ago
  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
- 4death4 3y ago
  Compare a Bolt (~3700 lbs) to a Fit (~2600 lbs).
- k4rli 3y ago
  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.

ramesh31 3y ago

>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-electric-aircraft/ 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 3y ago
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.
- majormajor 3y ago
  It's hard for me to imagine (in the US) the government allowing an explosion in small commercial flights w/o TSA and all that rigamarole. If you get 10x, 100x the volume today, with a less upper-crust passenger base, the perceived security/terrorism risk probably starts getting talked about.
  - JakeTheAndroid 3y ago
    and there is already a massive shortage of ATC employees right now. At minimum this would need to be addressed and more than double the workforce of ATC. That's without accounting for any additional infra that might be needed to support a 10x or 100x in traffic.
    - ramesh31 3y ago
      >That's without accounting for any additional infra that might be needed to support a 10x or 100x in traffic. The TSA requirement is nil for 10 person flights and these would be VFR only anyways. You would avoid a vast majority of the need for added ATC by operating between uncontrolled fields and relying on enhanced automation. The traditional airport model doesn't really apply when flights can be made so casually. Imagine a world where tiny runways that only service EVs are integrated into the city and you can hop between them as easily as catching a bus. Crosscountry travel would be also be possible via smaller hops, and cost less than a direct long haul jet liner ticket. All of that is enabled by the orders of magnitude reduction in operating costs. EV Alice is claiming $200/hr to operate an aircraft that has the equivalent performance to a $1k+/hr turbine within the range limitation.
      - JakeTheAndroid 3y ago
        > Imagine a world where tiny runways that only service EVs are integrated into the city and you can hop between them as easily as catching a bus. I mean, that sounds like a massive shift in infrastructure and city planning. I am not sure how efficient and affordable this would need to be to achieve that level of integration into daily society. Currently nothing, in the US at least, is setup to function this way. Whereas rail and roads are already deployed. And again, this ignores any of the issues brought on by scale. If this is the way we want people traveling at a 10x or 100x rate, the airspace is going to be busier and likely will need some sort of coordination, whether ATC or some other mechanism.
ToucanLoucan 3y ago
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 3y ago
Where do you confidently take the idea from, that electro motors for electric aircraft are cheaper to maintain than piston engines?
- deleted 3y ago
  [deleted]

scythe 3y ago

>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.

Manuel_D 3y ago
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).
- Sohcahtoa82 3y ago
  You just need a fast enough catapult mounted on a slope. ;-) An object dropped at 30,000 feet would be traveling at about 3,000 mph when it impacted the earth, ignoring the atmosphere. Maybe launch at 4,000 mph to overcome drag to throw something into cruising altitude? We'll just wear some noise canceling headphones to block out the OVERSPEED alarms.
  - Arelius 3y ago
    I mean, isn't ignoring the atmosphere ignoring like 90% of the domain?
  - bhandziuk 3y ago
    Just for perspective this is about mach 5. But I guess there is no speed of sound if you're ignoring the atmosphere :)
  - Night_Thastus 3y ago

thebruce87m 3y ago

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-equal-size 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

GauntletWizard 3y ago
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
4death4 3y ago
Compare a Bolt (~3700 lbs) to a Fit (~2600 lbs).
k4rli 3y ago
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.