4 ms·

How much denser do batteries have to get to feasibly power a large commercial jet from SF to LA? Do they need to include two of these inverters for redundancy?

0x8BADF00D 7y ago
With VTOL you only need enough energy to propel you to a high enough distance. Then you can glide. The higher up you go the farther you can travel.
- simongr3dal 7y ago
  If this method is so simple and so superior in saving energy would it not be the norm for fossil fueled air travel today?
- newnewpdro 7y ago
  Nit: There is no vertical landing in what you're describing, so VTOL doesn't seem appropriate.
  - iyw 7y ago
    aim straight down
- kbr2000 7y ago
  In order to move to your destination, after vertical take-off you would then need to fall down a bit first in order to pick up speed before transitioning to gliding (to get wind over your wings, which provides lift to turn and fly in the right direction). You might want to ditch those empty batteries also at the right point :)
Gibbon1 7y ago
It's been a while since I tried running numbers but I think if capacity increased 2X then electric would be a strong contender for distances under 500 miles.
jillesvangurp 7y ago
Quite long but it's the wrong question to ask. The reason that huge jets that cost in the order of hundreds of millions and burn tens of thousands of liters of fuel per flight are interesting at all is that their scale adds up to a reasonable fuel cost per passenger. Electric flight does not have this problem and nor does it have the scale advantage. Flying smaller electrical planes is more efficient on a kwh per passenger basis. It's also easier to build them technically. The SF to LA route is well in range for the Eviation Alice that should hit the market in the next few years. The variant they are advertising carries 9 passengers + 2 crew or 1,250kg of useful load for a bit over 1000 kilometers (including the required extra range) using 900kwh of batteries. This thing is supposedly entering certification after next year and should start hitting the market in a few years. This is obviously not a jet but the economics of flying this thing are very different. It completely destroys the business case for that. You charge it with cheap electricity. The unit cost is in the order of 3M$, it can fly in and out of any small airport, and it makes a lot less noise. One full charge would cost about 50-100 $ depending on how cheap you can get your electricity. Probably lower than that given improvements in cost of e.g. solar. For the price of 1 737, you could buy a few dozen of these. It can do a lot of things a big noisy jet can't do while being cheaper at it. Imagine a fleet of about 10000 of these flying back and forth all over California to any of the dozens of small airports. Deploying that amount of planes will take a few decades probably. Over that time you can expect improvements in range, battery efficiency and economies of scale. So, bigger, faster, cheaper happens as well. I'm not sure it will ever make sense to cram hundreds of people in an electrical plane. But why would you want to when the small ones eventually drop in price to a couple of tens to hundreds of K each and fly you from A to B autonomously for the price of a cup of coffee?
- mikysco 7y ago
  Love the perspective you present. It made me smile as a system of small, cheap, efficient planes would drastically change the way we think about human movement. So much potential and IMO, a pretty classical "technologist" style paradigm-shift... Creating demand for a service that didn't exist before and simultaneously solving the original problem (expensive, polluting air travel) as a byproduct.
- gugagore 7y ago

0x8BADF00D 7y ago

With VTOL you only need enough energy to propel you to a high enough distance. Then you can glide. The higher up you go the farther you can travel.

simongr3dal 7y ago
If this method is so simple and so superior in saving energy would it not be the norm for fossil fueled air travel today?
newnewpdro 7y ago
Nit: There is no vertical landing in what you're describing, so VTOL doesn't seem appropriate.
- iyw 7y ago
  aim straight down
kbr2000 7y ago
In order to move to your destination, after vertical take-off you would then need to fall down a bit first in order to pick up speed before transitioning to gliding (to get wind over your wings, which provides lift to turn and fly in the right direction). You might want to ditch those empty batteries also at the right point :)

Gibbon1 7y ago

It's been a while since I tried running numbers but I think if capacity increased 2X then electric would be a strong contender for distances under 500 miles.

jillesvangurp 7y ago

Quite long but it's the wrong question to ask. The reason that huge jets that cost in the order of hundreds of millions and burn tens of thousands of liters of fuel per flight are interesting at all is that their scale adds up to a reasonable fuel cost per passenger. Electric flight does not have this problem and nor does it have the scale advantage. Flying smaller electrical planes is more efficient on a kwh per passenger basis. It's also easier to build them technically. The SF to LA route is well in range for the Eviation Alice that should hit the market in the next few years. The variant they are advertising carries 9 passengers + 2 crew or 1,250kg of useful load for a bit over 1000 kilometers (including the required extra range) using 900kwh of batteries. This thing is supposedly entering certification after next year and should start hitting the market in a few years. This is obviously not a jet but the economics of flying this thing are very different. It completely destroys the business case for that. You charge it with cheap electricity. The unit cost is in the order of 3M$, it can fly in and out of any small airport, and it makes a lot less noise. One full charge would cost about 50-100 $ depending on how cheap you can get your electricity. Probably lower than that given improvements in cost of e.g. solar. For the price of 1 737, you could buy a few dozen of these. It can do a lot of things a big noisy jet can't do while being cheaper at it. Imagine a fleet of about 10000 of these flying back and forth all over California to any of the dozens of small airports. Deploying that amount of planes will take a few decades probably. Over that time you can expect improvements in range, battery efficiency and economies of scale. So, bigger, faster, cheaper happens as well. I'm not sure it will ever make sense to cram hundreds of people in an electrical plane. But why would you want to when the small ones eventually drop in price to a couple of tens to hundreds of K each and fly you from A to B autonomously for the price of a cup of coffee?

mikysco 7y ago
Love the perspective you present. It made me smile as a system of small, cheap, efficient planes would drastically change the way we think about human movement. So much potential and IMO, a pretty classical "technologist" style paradigm-shift... Creating demand for a service that didn't exist before and simultaneously solving the original problem (expensive, polluting air travel) as a byproduct.
gugagore 7y ago