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Anyone able to comment on if this is even possibly with current technology, and if not, in order of degree of difficulty & being critical to executing this, wha

Anyone able to comment on if this is even possibly with current technology, and if not, in order of degree of difficulty & being critical to executing this, what needs to be created for it to be realistically feasible?

aftbit 4y ago
The fundamental problem with electric aviation is the terrible specific energy & energy density of existing battery technology. Just for a very rough order-of-magnitude comparison, the most energy-dense batteries in common use today (lithium polymer cells) hold somewhere around 0.2-1 MJ/kg and 1-3 MJ/L [1]. Jet-A (kerosene) on the other hand holds somewhere around 40 MJ/kg [2]. Some of that might be recovered by using efficient electric motors instead of combustion engines, which are typically pretty inefficient, but even then we're still looking at a >4x decrease in fuel range. Notably though, these guys have pretty modest goals: >The 30-passenger planes will be driven by electric motors with battery-derived energy, allowing the planes to have a fully electric range of 200 kilometers (124 miles). The planes will also include a reserve-hybrid engine powered by sustainable aviation fuel, allowing it to have an extended range of up to 400 kilometers with a full flight. Energy lost to drag goes up with the cube of velocity, so flying slow, light planes over short hops might be doable with fully electric engines and modern batteries. As a side note, it's especially telling that they'll fly with a reserve engine that uses hydrocarbon fuel. This might be done for safety, but I would suspect it's more about making them economically viable while allowing them to be painted as a green alternative. Most routes will likely require at least some fuel consumption. 1: https://en.wikipedia.org/wiki/Lithium_polymer_battery https://en.wikipedia.org/wiki/Lithium_polymer_battery 2: https://en.wikipedia.org/wiki/Kerosene https://en.wikipedia.org/wiki/Kerosene
- O__________O 4y ago
  Yes, it was my understanding that battery capacity was the major barrier. To bad it’s not easy to just safely hot swap batteries in flight, which would likely solve the problem.
whateveracct 4y ago
There's a recent Sabine video about this very topic, actually. It didn't sound promising.
- O__________O 4y ago
  Thanks, assuming you mean Sabine Hossenfelder and this video: What's the Best Way to Make Air Travel Climate Friendly? https://youtube.com/watch?v=RVaVMyd0lI0 https://youtube.com/watch?v=RVaVMyd0lI0 Part on electric planes starts at 2:30 and only last a 3-4 mins.
tuatoru 4y ago
As the article itself says, electric will be fine for shorter flights, up to 200-250 miles, and up to 30 passengers. Cheaper than fueled. So the "hub-and-spoke" model of airports may be overlaid with a "dense mesh" of airfields. As I understand it, the bottleneck is the FAA. They are swamped with applications for type approvals. So much so that at least one company opted to develop a hydroplane instead of a land-based electric plane.
lwansbrough 4y ago
I know the world's first commercial certified electric plane[0] was flown recently by Harbour Air here in Vancouver. So it does seem as though the technology is here, at least on a small scale. I'm not sure whether the energy to weight ratio would be higher or lower for a larger plane. [0] https://harbourair.com/harbour-air-magnix-and-h55-partner-for-the-worlds-first-certified-all-electric-commercial-airplane/ https://harbourair.com/harbour-air-magnix-and-h55-partner-fo...
timbo1642 4y ago

aftbit 4y ago

The fundamental problem with electric aviation is the terrible specific energy & energy density of existing battery technology. Just for a very rough order-of-magnitude comparison, the most energy-dense batteries in common use today (lithium polymer cells) hold somewhere around 0.2-1 MJ/kg and 1-3 MJ/L [1]. Jet-A (kerosene) on the other hand holds somewhere around 40 MJ/kg [2]. Some of that might be recovered by using efficient electric motors instead of combustion engines, which are typically pretty inefficient, but even then we're still looking at a >4x decrease in fuel range. Notably though, these guys have pretty modest goals: >The 30-passenger planes will be driven by electric motors with battery-derived energy, allowing the planes to have a fully electric range of 200 kilometers (124 miles). The planes will also include a reserve-hybrid engine powered by sustainable aviation fuel, allowing it to have an extended range of up to 400 kilometers with a full flight. Energy lost to drag goes up with the cube of velocity, so flying slow, light planes over short hops might be doable with fully electric engines and modern batteries. As a side note, it's especially telling that they'll fly with a reserve engine that uses hydrocarbon fuel. This might be done for safety, but I would suspect it's more about making them economically viable while allowing them to be painted as a green alternative. Most routes will likely require at least some fuel consumption. 1: https://en.wikipedia.org/wiki/Lithium_polymer_battery https://en.wikipedia.org/wiki/Lithium_polymer_battery 2: https://en.wikipedia.org/wiki/Kerosene https://en.wikipedia.org/wiki/Kerosene

O__________O 4y ago
Yes, it was my understanding that battery capacity was the major barrier. To bad it’s not easy to just safely hot swap batteries in flight, which would likely solve the problem.

whateveracct 4y ago

There's a recent Sabine video about this very topic, actually. It didn't sound promising.

O__________O 4y ago
Thanks, assuming you mean Sabine Hossenfelder and this video: What's the Best Way to Make Air Travel Climate Friendly? https://youtube.com/watch?v=RVaVMyd0lI0 https://youtube.com/watch?v=RVaVMyd0lI0 Part on electric planes starts at 2:30 and only last a 3-4 mins.

tuatoru 4y ago

As the article itself says, electric will be fine for shorter flights, up to 200-250 miles, and up to 30 passengers. Cheaper than fueled. So the "hub-and-spoke" model of airports may be overlaid with a "dense mesh" of airfields. As I understand it, the bottleneck is the FAA. They are swamped with applications for type approvals. So much so that at least one company opted to develop a hydroplane instead of a land-based electric plane.

lwansbrough 4y ago

I know the world's first commercial certified electric plane[0] was flown recently by Harbour Air here in Vancouver. So it does seem as though the technology is here, at least on a small scale. I'm not sure whether the energy to weight ratio would be higher or lower for a larger plane. [0] https://harbourair.com/harbour-air-magnix-and-h55-partner-for-the-worlds-first-certified-all-electric-commercial-airplane/ https://harbourair.com/harbour-air-magnix-and-h55-partner-fo...

timbo1642 4y ago