9 ms·

One of the things that helped Southwest dominate in the short-haul space, particularly in the Texas Triangle, was optimizing "turn-time" with a target of less t

One of the things that helped Southwest dominate in the short-haul space, particularly in the Texas Triangle, was optimizing "turn-time" with a target of less than 10 minutes to both deplane and board passengers (10 minutes!)[0] I wonder how lengthy charge cycles will affect the viability of fast turn times, especially for the short-haul segments that they're targeting for these new airliners. It seems like they'll need to either have extremely fast charging or be prepared for significant downtime between flights; where will the planes be stored while they're charging? It's important to both invest in and appear to be investing in the future, but even a soft commitment of 100 planes seems like quite a bit, especially in the very competitive and cost-focused short-haul space. 0. https://www.npr.org/2015/06/28/418147961/the-man-who-saved-southwest-airlines-with-a-10-minute-idea https://www.npr.org/2015/06/28/418147961/the-man-who-saved-s...

wtvanhest 5y ago
That seems like an important question. Maybe they will have a lot of individual batteries that they can charge simultaneously. Alternatively, maybe they could swap out the bottom of the fuselage or wings.
tadfisher 5y ago
Battery swaps could be viable, barring some complications in gate infrastructure and airframe design. Obviously this would be impossible if airframe designers incorporate battery cells in structural members, as some suggest to offset the weight penalty.
- nielsbot 5y ago
  The "more info" page on their website says they are ruling out battery swaps, at least for now, since a battery swap would require a mechanical certification every time it was done. They are swappable though: they explain that used battery packs can be replaced and that used packs can be used for a second purpose with less stringent requirements. For example, an energy storage facility at the airport.
- hutzlibu 5y ago
  "Obviously this would be impossible if airframe designers incorporate battery cells in structural members, as some suggest to offset the weight penalty." Why not do both? Swap one part and charge just the internal batteries. But internal batteries does not sound so clever with limited lifetime anyway.
  - tgsovlerkhgsel 5y ago
    Charging is limited by two factors: - the power you can get from the charger to the batteries - the power the cells can accept You can reasonably easily fix the first point with custom infrastructure, so the second point will be the limiting factor, and that one means that it always takes e.g. 20 minutes to charge your batteries, regardless how many you're charging (because with a bigger battery, you're simply charging more cells in parallel, at the same speed per cell).
    - justaguy88 5y ago
      I've always wondered about this, do electric cars charge each cell in parallel? or are there some series connections?
- Tossrock 5y ago
  I've said for a while that electric planes are the perfect use case for aluminum-air batteries. Aluminum-air batteries have up to 8x the energy density of lithium ion, but are not rechargeable, so using them only makes sense if you have a system to recycle the used batteries. This doesn't make a ton of sense with cars, because cars are constantly going from random place to random place, and having to include a stop at a battery recycling center every ~1000km or whatever would be impractical. But planes go between very limited sets of known points, with huge amounts of infrastructure. Adding in the capability to do Al-air battery swaps / recycling would be easy, and the benefits for the use case (huge weight savings, faster turnaround times by swapping vs charging) are big.
  - otterley 5y ago
    What's the process for recycling an aluminum-air battery? And is it cost/energy effective to do so? (If you think about it, closed-loop recycling of energy storage is just another form of recharging, but with extra steps.)
    - Infernal 5y ago
      From wikipedia[0] "it is possible to mechanically recharge the battery with new aluminium anodes made from recycling the hydrated aluminium oxide". I've found a few papers regarding recovery of aluminum from aluminum oxides, but I don't have the background to interpret them with an eye towards that process's impact on the overall efficiency of the battery. [0] https://en.wikipedia.org/wiki/Aluminium–air_battery https://en.wikipedia.org/wiki/Aluminium–air_battery
      - throwawayboise 5y ago
        Production of aluminum metal from aluminum oxide is hugely energy-intensive. Aluminum plants often have an on-site utility-size power plant to provide the electricity. Is this same energy needed to recycle the oxide from the batteries? If so it seems like a non-starter, maybe unless it could be done with solar generation.
deleted 5y ago
[deleted]
NickM 5y ago
Even if they don't have super fast chargers or battery swaps, I'd imagine the cost of longer turn times might be offset by the substantially lower fuel costs.
908B64B197 5y ago
If they use them to fly to and from tiny airports they might fly only a few times per day with enough time to recharge in-between (because there's no demand). Since the planes themselves are really small, they also won't spend a long time at the gate so they could be transported to a maintenance hangar to recharge.
ehnto 5y ago
That's part of what made high speed rail so compelling. When done well you can be on the train, sat down and moving in just a few minutes. No airport security, long ticketing lines, baggage check-ins or fuss at the gate. Just walk in, bags in the overhead, sit down and away you go.
- darkwizard42 5y ago
  I think high speed rail is compelling because of the speed and accessibility (which if built right -- looking at Japan) becomes an easy option for commute and transport between cities that is vastly more accessible than airports (Narita airport is FAR from Tokyo central) The security check in, long ticket lines, etc. are all byproducts of security theater that has come through and honestly in the US, with TSA Pre, I'm pretty sure I spend more time sitting at the gate than ANY other process (check in, 5 min, security, 5 min, walking to gate, 5 min, sitting at gate waiting for boarding, 40 min) 100% agree that the ability to walk straight into a train, find your seat through multiple doors (even the wrong car) feels pretty good.
  - tommi 5y ago
    Well said though to clarify the reason why you wait 40 minutes at the gate is probably because you have to calculate some extra per each step leading to it. You can't be sure you'll make it in 5 minutes per check in, security and walk to the gate. Also, the added cost in time and money of missing a plane is quite high compared to missing a train e.g. in Europe, so that further increases the buffer you add to the process.
    - darkwizard42 5y ago
      Yeah this is a good point... I definitely don't want to miss my flight and now I have a really good and predictable handle on how long security and check in takes, but I never seem to have a good handle on how boarding will go (I usually just abide by the "domestic gates never close till 30 min before the flight earliest" rule)
    - NotSammyHagar 5y ago
legitster 5y ago
I think that the turnaround time is less important for the really small jets they are considering.
- mbreese 5y ago
  I think it’s more important. A wide body long-haul plane takes a significant amount of time to turn around w.r.t. many other aspects — more passengers, cargo/luggage, fuel, food, etc. the bigger the plane, the longer this takes. I’ve been on small commuter planes that turn around in 20-30 min, landing to take off. These are the planes that turn around quickly as there are fewer passengers, they carry less baggage, and you don’t always need to refuel. If anything, these shorter routes are more time-sensitive.
mapt 5y ago
Small-market, heavily subsidized short-haul segments fly half empty, and have a low flight cadence.
Hypx_ 5y ago
Electric airplanes are increasingly just gadgetbahns of the sky. None of the are even remotely feasible, and reading the comments here it's clear that even if they did exist they'd be immediately disrupted by existing airplanes. I think it's time we stop giving them any more thought as they simply cannot work.

wtvanhest 5y ago

That seems like an important question. Maybe they will have a lot of individual batteries that they can charge simultaneously. Alternatively, maybe they could swap out the bottom of the fuselage or wings.

tadfisher 5y ago

Battery swaps could be viable, barring some complications in gate infrastructure and airframe design. Obviously this would be impossible if airframe designers incorporate battery cells in structural members, as some suggest to offset the weight penalty.

nielsbot 5y ago
The "more info" page on their website says they are ruling out battery swaps, at least for now, since a battery swap would require a mechanical certification every time it was done. They are swappable though: they explain that used battery packs can be replaced and that used packs can be used for a second purpose with less stringent requirements. For example, an energy storage facility at the airport.
hutzlibu 5y ago
"Obviously this would be impossible if airframe designers incorporate battery cells in structural members, as some suggest to offset the weight penalty." Why not do both? Swap one part and charge just the internal batteries. But internal batteries does not sound so clever with limited lifetime anyway.
- tgsovlerkhgsel 5y ago
  Charging is limited by two factors: - the power you can get from the charger to the batteries - the power the cells can accept You can reasonably easily fix the first point with custom infrastructure, so the second point will be the limiting factor, and that one means that it always takes e.g. 20 minutes to charge your batteries, regardless how many you're charging (because with a bigger battery, you're simply charging more cells in parallel, at the same speed per cell).
  - justaguy88 5y ago
    I've always wondered about this, do electric cars charge each cell in parallel? or are there some series connections?
Tossrock 5y ago
I've said for a while that electric planes are the perfect use case for aluminum-air batteries. Aluminum-air batteries have up to 8x the energy density of lithium ion, but are not rechargeable, so using them only makes sense if you have a system to recycle the used batteries. This doesn't make a ton of sense with cars, because cars are constantly going from random place to random place, and having to include a stop at a battery recycling center every ~1000km or whatever would be impractical. But planes go between very limited sets of known points, with huge amounts of infrastructure. Adding in the capability to do Al-air battery swaps / recycling would be easy, and the benefits for the use case (huge weight savings, faster turnaround times by swapping vs charging) are big.
- otterley 5y ago
  What's the process for recycling an aluminum-air battery? And is it cost/energy effective to do so? (If you think about it, closed-loop recycling of energy storage is just another form of recharging, but with extra steps.)
  - Infernal 5y ago
    From wikipedia[0] "it is possible to mechanically recharge the battery with new aluminium anodes made from recycling the hydrated aluminium oxide". I've found a few papers regarding recovery of aluminum from aluminum oxides, but I don't have the background to interpret them with an eye towards that process's impact on the overall efficiency of the battery. [0] https://en.wikipedia.org/wiki/Aluminium–air_battery https://en.wikipedia.org/wiki/Aluminium–air_battery
    - throwawayboise 5y ago
      Production of aluminum metal from aluminum oxide is hugely energy-intensive. Aluminum plants often have an on-site utility-size power plant to provide the electricity. Is this same energy needed to recycle the oxide from the batteries? If so it seems like a non-starter, maybe unless it could be done with solar generation.

deleted 5y ago

[deleted]

NickM 5y ago

Even if they don't have super fast chargers or battery swaps, I'd imagine the cost of longer turn times might be offset by the substantially lower fuel costs.

908B64B197 5y ago

If they use them to fly to and from tiny airports they might fly only a few times per day with enough time to recharge in-between (because there's no demand). Since the planes themselves are really small, they also won't spend a long time at the gate so they could be transported to a maintenance hangar to recharge.

ehnto 5y ago

That's part of what made high speed rail so compelling. When done well you can be on the train, sat down and moving in just a few minutes. No airport security, long ticketing lines, baggage check-ins or fuss at the gate. Just walk in, bags in the overhead, sit down and away you go.

darkwizard42 5y ago
I think high speed rail is compelling because of the speed and accessibility (which if built right -- looking at Japan) becomes an easy option for commute and transport between cities that is vastly more accessible than airports (Narita airport is FAR from Tokyo central) The security check in, long ticket lines, etc. are all byproducts of security theater that has come through and honestly in the US, with TSA Pre, I'm pretty sure I spend more time sitting at the gate than ANY other process (check in, 5 min, security, 5 min, walking to gate, 5 min, sitting at gate waiting for boarding, 40 min) 100% agree that the ability to walk straight into a train, find your seat through multiple doors (even the wrong car) feels pretty good.
- tommi 5y ago
  Well said though to clarify the reason why you wait 40 minutes at the gate is probably because you have to calculate some extra per each step leading to it. You can't be sure you'll make it in 5 minutes per check in, security and walk to the gate. Also, the added cost in time and money of missing a plane is quite high compared to missing a train e.g. in Europe, so that further increases the buffer you add to the process.
  - darkwizard42 5y ago
    Yeah this is a good point... I definitely don't want to miss my flight and now I have a really good and predictable handle on how long security and check in takes, but I never seem to have a good handle on how boarding will go (I usually just abide by the "domestic gates never close till 30 min before the flight earliest" rule)
  - NotSammyHagar 5y ago

legitster 5y ago

I think that the turnaround time is less important for the really small jets they are considering.

mbreese 5y ago
I think it’s more important. A wide body long-haul plane takes a significant amount of time to turn around w.r.t. many other aspects — more passengers, cargo/luggage, fuel, food, etc. the bigger the plane, the longer this takes. I’ve been on small commuter planes that turn around in 20-30 min, landing to take off. These are the planes that turn around quickly as there are fewer passengers, they carry less baggage, and you don’t always need to refuel. If anything, these shorter routes are more time-sensitive.

mapt 5y ago

Small-market, heavily subsidized short-haul segments fly half empty, and have a low flight cadence.

Hypx_ 5y ago

Electric airplanes are increasingly just gadgetbahns of the sky. None of the are even remotely feasible, and reading the comments here it's clear that even if they did exist they'd be immediately disrupted by existing airplanes. I think it's time we stop giving them any more thought as they simply cannot work.