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Electric Flying Cars May Be Possible with New Batteries

17 points by MindGods 5y ago

mullen 5y ago
Why is there an obsession with Flying Cars? The last thing I ever want to see is the average American driver or below average American driver flying a car. Anytime I think of a person who "rolls coal" or gets angry driving, I shudder to think that someday, they might have access to a Flying Car.
- noahtallen 5y ago
  More than one of the new flying car / flying taxi / electric plane concepts are autonomous. Imo, this tech is more about: 1. Making short flights more viable 2. Making electric planes more viable 3. Seeing if AI is viable as a pilot I also really doubt the FAA is going to just let anyone fly an electric “car”, given how non-trivial getting a pilot’s license is. Maybe there’s a middle ground for drone-type planes which probably have a “simpler” flight model than a plane or helicopter, but I can’t see it being just anyone. Even flying at night or flying in a cloud requires even further licensing and training since you can’t see where you’re going like you can with a car. Can’t see that going away either
  - awillen 5y ago
    Right now my understanding is many of the eVTOL companies are trying to make the UI simple enough that it does not require a pilot, but rather an operator, which is a much lower bar in terms of training. The objective is then really to use these as air taxis/Ubers, not individually owned cars. United, for example, is planning to use them to shuttle passengers to/from LAX, which makes a ton of sense, because they can go from designated points (as opposed to something like curbside pickup, where they'd have to find space to land), and they're hitting an ideal use case of avoiding traffic that is predictably heavy. Obviously if/when AI is viable, that makes them even more useful.
- pixel_tracing 5y ago
  I think stricter licensing and maybe even a mandatory psych evaluation beforehand might help?
- Sohcahtoa82 5y ago
  I think the problem of a "flying car" is that it will require a pretty major redefinition of "car". The way I see it, you have two common ways of generating lift: You either have spinning rotors on a vertical axis, like a helicopter or drone, or you have a propeller that pulls the vehicle forward, with air traveling over the wings to generate lift. If your idea of a flying car resembles the drone or helicopter, when we already have them, they're called helicopters. If you think of something with wings, when we already have them in the form of ultralight aircraft and small Cessnas. Neither of which are cars, and neither would you want in your neighborhood, since they're incredibly loud. Now, I know know Aeromobile exists and has created a plane with wings that fold and can be driven on streets, but it looks like it'd just be shitty as a car AND a plane.
- deleted 5y ago
  [deleted]
rochansinha 5y ago
Link to the original article ‘Challenges and key requirements of batteries for electric vertical takeoff and landing aircraft ‘: https://www.cell.com/joule/fulltext/S2542-4351(21)00205-1 https://www.cell.com/joule/fulltext/S2542-4351(21)00205-1
baybal2 5y ago
Well, a wrong incentive. A battery being charged can get to 60° without any help, usually it is a problem. Any battery above around 20kWh will need very good cooling for any much high charging speed. Battery volumes scale nonlinearly with their cooling needs, obviously. And big batteries require heavy cooling systems. Under 20kWh packs may not need a cooling system as such, which is a big, big cost, weight, and complexity saver. This way, a faster recharging, but smaller, and more durable battery might be way more practical in kms driven vs. hours spent charging. Telsa gets 5 km per kWh, and takes an eternity to charge, Renault Twizy gets almost 10 km per kWh, and charges at 12 km per minute with aftermarket fast charger.
- Yaggo 5y ago
  > Telsa gets 5 km per kWh, and takes an eternity to charge, Renault Twizy gets almost 10 km per kWh, and charges at 12 km per minute with aftermarket fast charger. This is very misleading. Twizy is a two-person mini car. It gets good range for its battery size when driven slowly (like 45 km/h) but at speeds comparable to regular cars it loses its advantage. It's lightweight but not very aerodynamic. The "high-end" version of Twizy is limited to 80 km/h and won't give much range at that speed. Also, it takes 3 hours to charge its 6 kWh battery, i.e. the charging power is roughly 2 kW, i.e. charging power to capacity ratio is only 2/6 = 0.3C, not very much. Liquid-cooled full size cars such as Tesla can be quick charged even at peak of 3C (!), i.e. 50 kWh battery can take 170 kW for a short time and 1C for long time. That's MUCH quicker charging than Twizy. Sure, home-charging the Model 3 SR+ takes 5 hours even with maximum 11 kW power, but it's mainly intented for overnight use, and then again gives you massive range of 600 km or so when driven Twizy's speeds (if not more). I agree that generally smaller cars gets better range more easily, i.e. aerodynamic body shape such as Model 3 can get the same range with 50 kWh battery than much bigger SUV shaped car with 80 kWh battery. If both cars have the same quick charging power (in kilowatts), the smaller cars gives you much better charging speed in km/h, due to its lower consumption, thus travels long distances faster.
  - baybal2 5y ago
    > That's MUCH quicker charging than Twizy I wrote that it involves aftermarket charger. But the principle remains the same with a bit heavier cars. A smaller battery, on a smaller, lighter vehicle which gets a lot of kms per kwh can potentially be spending less, or equal time charging than bigger cars per km of travel in daily use. And they will have the advantage of not killing its battery with 3C charging while still proving adequate kms/per minute charging. Hyundai Ioniq is a good example. That's why I see mainstream EV economy class to spring around 15-30 kwh battery sizes, simple uncooled/air cooled LFP battery packs, along with moderately fast charging, and aim at high real world km/kwh digits.

17 points by MindGods 5y ago

Why is there an obsession with Flying Cars? The last thing I ever want to see is the average American driver or below average American driver flying a car. Anytime I think of a person who "rolls coal" or gets angry driving, I shudder to think that someday, they might have access to a Flying Car.

noahtallen 5y ago
More than one of the new flying car / flying taxi / electric plane concepts are autonomous. Imo, this tech is more about: 1. Making short flights more viable 2. Making electric planes more viable 3. Seeing if AI is viable as a pilot I also really doubt the FAA is going to just let anyone fly an electric “car”, given how non-trivial getting a pilot’s license is. Maybe there’s a middle ground for drone-type planes which probably have a “simpler” flight model than a plane or helicopter, but I can’t see it being just anyone. Even flying at night or flying in a cloud requires even further licensing and training since you can’t see where you’re going like you can with a car. Can’t see that going away either
- awillen 5y ago
  Right now my understanding is many of the eVTOL companies are trying to make the UI simple enough that it does not require a pilot, but rather an operator, which is a much lower bar in terms of training. The objective is then really to use these as air taxis/Ubers, not individually owned cars. United, for example, is planning to use them to shuttle passengers to/from LAX, which makes a ton of sense, because they can go from designated points (as opposed to something like curbside pickup, where they'd have to find space to land), and they're hitting an ideal use case of avoiding traffic that is predictably heavy. Obviously if/when AI is viable, that makes them even more useful.
pixel_tracing 5y ago
I think stricter licensing and maybe even a mandatory psych evaluation beforehand might help?
Sohcahtoa82 5y ago
I think the problem of a "flying car" is that it will require a pretty major redefinition of "car". The way I see it, you have two common ways of generating lift: You either have spinning rotors on a vertical axis, like a helicopter or drone, or you have a propeller that pulls the vehicle forward, with air traveling over the wings to generate lift. If your idea of a flying car resembles the drone or helicopter, when we already have them, they're called helicopters. If you think of something with wings, when we already have them in the form of ultralight aircraft and small Cessnas. Neither of which are cars, and neither would you want in your neighborhood, since they're incredibly loud. Now, I know know Aeromobile exists and has created a plane with wings that fold and can be driven on streets, but it looks like it'd just be shitty as a car AND a plane.
deleted 5y ago
[deleted]

rochansinha 5y ago

Link to the original article ‘Challenges and key requirements of batteries for electric vertical takeoff and landing aircraft ‘: https://www.cell.com/joule/fulltext/S2542-4351(21)00205-1 https://www.cell.com/joule/fulltext/S2542-4351(21)00205-1

baybal2 5y ago

Well, a wrong incentive. A battery being charged can get to 60° without any help, usually it is a problem. Any battery above around 20kWh will need very good cooling for any much high charging speed. Battery volumes scale nonlinearly with their cooling needs, obviously. And big batteries require heavy cooling systems. Under 20kWh packs may not need a cooling system as such, which is a big, big cost, weight, and complexity saver. This way, a faster recharging, but smaller, and more durable battery might be way more practical in kms driven vs. hours spent charging. Telsa gets 5 km per kWh, and takes an eternity to charge, Renault Twizy gets almost 10 km per kWh, and charges at 12 km per minute with aftermarket fast charger.

Yaggo 5y ago
> Telsa gets 5 km per kWh, and takes an eternity to charge, Renault Twizy gets almost 10 km per kWh, and charges at 12 km per minute with aftermarket fast charger. This is very misleading. Twizy is a two-person mini car. It gets good range for its battery size when driven slowly (like 45 km/h) but at speeds comparable to regular cars it loses its advantage. It's lightweight but not very aerodynamic. The "high-end" version of Twizy is limited to 80 km/h and won't give much range at that speed. Also, it takes 3 hours to charge its 6 kWh battery, i.e. the charging power is roughly 2 kW, i.e. charging power to capacity ratio is only 2/6 = 0.3C, not very much. Liquid-cooled full size cars such as Tesla can be quick charged even at peak of 3C (!), i.e. 50 kWh battery can take 170 kW for a short time and 1C for long time. That's MUCH quicker charging than Twizy. Sure, home-charging the Model 3 SR+ takes 5 hours even with maximum 11 kW power, but it's mainly intented for overnight use, and then again gives you massive range of 600 km or so when driven Twizy's speeds (if not more). I agree that generally smaller cars gets better range more easily, i.e. aerodynamic body shape such as Model 3 can get the same range with 50 kWh battery than much bigger SUV shaped car with 80 kWh battery. If both cars have the same quick charging power (in kilowatts), the smaller cars gives you much better charging speed in km/h, due to its lower consumption, thus travels long distances faster.
- baybal2 5y ago
  > That's MUCH quicker charging than Twizy I wrote that it involves aftermarket charger. But the principle remains the same with a bit heavier cars. A smaller battery, on a smaller, lighter vehicle which gets a lot of kms per kwh can potentially be spending less, or equal time charging than bigger cars per km of travel in daily use. And they will have the advantage of not killing its battery with 3C charging while still proving adequate kms/per minute charging. Hyundai Ioniq is a good example. That's why I see mainstream EV economy class to spring around 15-30 kwh battery sizes, simple uncooled/air cooled LFP battery packs, along with moderately fast charging, and aim at high real world km/kwh digits.