
Battery supply problems faced by electric air taxis - prostoalex
https://www.aviationtoday.com/2020/02/03/battery-supply-problems-faced-electric-air-taxis/
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code4tee
The Achilles heel of electric aviation is that batteries don’t shed weight as
they discharge. A fundamental aspect of Aerospace engineering is that
rockets/planes shed a lot of weight during flight by by burning fuel. Many big
jets take off at weights far too heavy to land and long ranges are only
possible because of all the weight shed in flight.

Until that issue can be addressed with electric aviation, electric planes will
be a concept limited to very short range flying.

Rockets solve this problem by dumping the dead weight overboard but not sure a
bunch of dead airplane batteries parachuting back to earth is a viable
approach.

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repiret
Don’t conflate rockets and airplanes. Most of the energy an airplane uses is
to overcome parasitic drag – to overcome the air resistance caused by moving
forward through the air mass. While some of the energy is used to keep the
plane in the air, that is not dominant. Yes, planes have a higher maximum
takeoff weight then maximum landing weight, but that has to do with the design
of the landing gear, in some hypothetical world where jet fuel did not shed
weight, planes would only have slightly worse range.

The real problem with electric aviation is that batteries have terrible weight
to energy ratios compared to fossil fuels.

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mogadsheu
It’s pretty clear that battery technology and cost efficiency is going to have
to advance substantially before it can have a meaningful impact on air
transport.

Blimps might be a slight exception.

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sliken
Or just use hydrogen, it's a much denser energy storage medium, and airflight
is less cost sensitive than ground transportation.

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tonyedgecombe
Or not bother with air taxis, civilisation won't collapse because some rich
arsehole can't get across New York in five minutes.

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ClumsyPilot
Sure, but on another hand we should encourage the rich asshole to spend his
money so it could be useful to the rest of the economy.

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Scoundreller
Universal basic income and massive carbon taxes to pay for it!

It’s about time we tax actual destruction, not a minimum wage earner’s Netflix
subscription.

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himinlomax
Best way to do it I've ever seen is the automated transactions tax, whereby
you replace most taxes with a small percentage taken on every financial
transaction (plus a larger one when converting to/from cash to account for the
black economy).

It's progressive because poor people will only pay twice (once on their
salary/benefits, once when buying stuff), whereas rich people will pay several
times when moving money around.

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organsnyder
Expect a new class of companies to spring up overnight that are dedicated to
bundling transactions to avoid this new tax. For instance, I could make a
single transaction to my broker that covered all of my expected expenditures
for the month, and that broker would then disburse it to my payees, bundling
it with funds from other payers to avoid the tax on the other end.

I am strongly in favor of a tax on all stock market transactions,
though—anything to deter HFT, which IMHO has little societal benefit while
externalizing a _ton_ of risk.

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gamblor956
Wouldn't work. Tax law can tell the difference between an individual
transaction and bundled transactions. It's also the only area of law that
allows for ex post facto changes to the criminality of acts.

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syllable_studio
In the chart from the article I see that capacitors are shown as having high
specific power. Would it not work to use a hybrid approach of capacitors for
takeoff and then Li-ion for most of the flight? I know it would make the
system more complicated and therefore more expensive up front, but I wonder if
it's an option or if it's out of the question for one reason or another. I've
read that supercapacitors are being used for busses and other applications.
[https://en.wikipedia.org/wiki/Supercapacitor](https://en.wikipedia.org/wiki/Supercapacitor)

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fw_double_e
Capacitors are great for high load requirements but not great as an energy
storage device. i.e. if you wanted to draw several hundred amps for a second
or two with relatively low heat waste, an ultra-capacitor arrangement would be
the way to go, but for energy storage, a battery wins hands down. There's huge
research going into expanding the capacity of capacitors.

Check out this video about capacitors:
[https://www.youtube.com/watch?v=EoWMF3VkI6U](https://www.youtube.com/watch?v=EoWMF3VkI6U)

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bgarrettglaser
PS -- author here, happy to discuss.

