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cagenut said 6 months ago:

I went down an electric-flight youtube rabbit hole a couple months ago and was genuinely shocked at how far things have already developed. If anyone else is curious, check out this set of presentations from the 2018 "sustainable aviation foundation" symposium: https://www.youtube.com/channel/UCHtqxcrPbJkSwI-ozYr1AiQ/vid...

The 2019 symposium is coming up in october: https://www.sasymposium.com/

Also Uber just had its "elevate summit" on its flight plans (all electric): https://www.youtube.com/playlist?list=PLmVTG4mAK7nyJ7pu7pTd_...

Basically, any question you have, someone has devoted the last few years of their career to and given a 45 minute presentation on.

cagenut said 6 months ago:

Some more e-flight youtubes:

This is the specific plane mentioned in the article: https://www.youtube.com/watch?v=REdh3Q4cPuE

That guy did a great roundup video of electric flight a few months ago: https://www.youtube.com/watch?v=vIM3pgxHVIM

He also did a tour of the Pipestrel plan a month ago where you get to see some "under the hood" stuff: https://www.youtube.com/watch?v=qfjCXDf9rhk

leoedin said 6 months ago:

I wonder what the life of the aircraft needs to be before the higher cost of the aircraft amortises into lower overall costs. I'd imagine that the running cost of a mainly solid state aircraft is significantly lower than a gasoline one, but the initial battery cost will be very significant. It would be nice if the rise of electric general aviation has the effect of reducing the cost of flying.

However, I suspect then you'll run into other issues. I can't imagine LA can have too many air taxis flying around before they become a nightmare to manage. If the hourly cost of an air taxi is low enough that everyone can take one, the sky will become saturated. There's obviously a lot of space, but our systems for managing air traffic right now are designed around there being tens to hundreds of aircraft in the same area, not thousands. We'd need to introduce fully automated aircraft routing to have a hope of dealing with air taxis over dense cities if they became remotely popular.

rbanffy said 6 months ago:

Being simpler than turboprop or piston, I assume maintenance is cheaper. That has a long term impact as airframes are used for decades before being deemed uneconomical or otherwise unfit for purpose.

Battery prices can be offset by cheaper electricity and/or carbon taxes.

Less noisy planes should also be able to operate in areas jets aren't, such as extremely desirable urban centers. eVTOL is even better in that, but developments that would make it rival fixed wing are coming, eventually. If a V-22 can do it, so can civilians.

ATC is the choking point - we'll have to take a lesson from the phone system, which transitioned from having human operators routing calls to all of us recognizing dial-busy-ring tones and being able to dial numbers ourselves.

aedocw said 6 months ago:

No one who has ever flown a plane in moderately busy airspace (like desirable urban centers) would talk about transitioning ATC to something without humans.

As it stands, in non-controlled airspace, it already works like this. Pilots announce their intentions and coordinate with each other. This only works in areas with very low traffic.

rbanffy said 6 months ago:

Nobody would suggest human coordination in this scenario. It's more like machines negotiating directly or assisting the negotiation so that all craft in the given volume agree on what it looks like and what it'll be in the next few minutes.

There are some very interesting research topics in there in how to achieve this distributed consensus and how to deal with malicious actors trying to disrupt the air traffic in the region.

radicalbyte said 6 months ago:

I can't see how they compete when electricity is taxed whilst aviation fuel is untaxed.

sokoloff said 6 months ago:

Airline fuel is largely untaxed, but most other aviation fuel is taxed.

General aviation 100LL ("avgas") fuel is taxed federally at $0.191/gallon (or $0.335/gallon for certain ownership structures).

General aviation jet fuel is taxed at $0.219 (to as much as $0.244) per gallon.

Highway fuel is taxed federally at $0.184/gallon (slightly less than avgas).

Electric aircraft are not poised to disrupt the jet-fuel burning sector of aviation. The aircraft in this article will be competing against aircraft using taxed fuel (100LL).

iancmceachern said 6 months ago:

Why is airline fuel untaxed?

sokoloff said 6 months ago:

I assume because the feds calculated that they can collect more revenue by taxing elements of the tickets rather than the fuel, but I really don't know.

(Note that some states do tax airline jet fuel and some airports assess a flowage fee per gallon [which is for practical purposes equivalent to a sales tax].)

benj111 said 6 months ago:

Airline jet fuel duty is covered by international agreements I think, presumably to facilitate trade.

I don't know if that also applies to purely domestic use though. Maybe that's how states can impose a tax?

benj111 said 6 months ago:

Why should tax inherently make it uncompetitive?

Has untaxed rooftop solar always been cheaper than some other taxed energy source?

benj111 said 6 months ago:

I cant help but feel they could have found a more fun headline.

Anyway, lithium sulphur is mentioned


Could anyone add more background? Is this something we're likely to be seeing in EVs any time soon?

pattisapu said 6 months ago:

"Quantum Buy Bye in Electric Tech Urban Air Dare"

benj111 said 6 months ago:

I was toying with

"Quantum says good buy, and Bye says hello."

I think it's a bit too high brow for a head line though.

quickthrower2 said 6 months ago:

That was a hard headline to parse. First “Quantum air” when there is already Qantas. And then “buys Bye’s”. Eek!

FabHK said 6 months ago:

They claim 4 hours endurance, which would give it nearly 400 NM range. Not bad, if it works. The 4 seater can carry 800 lbs. Wonder how long charging takes.


dmitrygr said 6 months ago:

For carrying scheduled air passengers, you need to fly IFR. You need to have fuel to fly to destination airport, then to reserve airport, and then 45 minutes. No sane pilot flies with that little reserve. Most airlines have enough for destination, reserve, and 90-120 minutes. With that safety margin, this thing has a "useful" range of maybe 150 nautical miles

FabHK said 6 months ago:

This is not scheduled, but Air Taxi, which I believe is a different part of the FAR. And, yes, for small planes, there are plenty of alternate airports. I'd say 200 NM or more are realistic.

wongarsu said 6 months ago:

However it's a four-seater that has substantially more landing options than a 747.

Scoundreller said 6 months ago:

For floatplanes, you can nix some of those requirements.

kart23 said 6 months ago:

Looks good. They seem to be pretty cheap, and with a low operating cost, would be quite appealing even for private fliers. A rental service for these would be amazing. Plenty of people would rent it out for fun, unique day trips that would hopefully only be a couple times more expensive than a car, albeit with stricter licensing requirements.

FabHK said 6 months ago:

FWIW, you can rent a Cessna 172 for less than $200 per hour, and take it in a trip where you agree to fly at least say one or two hours per day, depending on location and season etc.

So, that’s only a few times more expensive than a car, and quite a bit more fun.

chmars said 6 months ago:

In practice, 4 hours of endurance give you around 2.5 to 3 hours of actual flight. You must plan for an alternate and with Reserve fuel. And you might not get all the clearances you expect.

Charging will take in any case much longer than refueling.

rbanffy said 6 months ago:

Long charging times are only an issue if the batteries aren't removable. An electric plane with two sets of batteries on each end of its route can pretty much fly non-stop.

jillesvangurp said 6 months ago:

This removing batteries thing comes up a lot on HN. People seem obsessed with it and are coming up with all sorts of theories as to how this is absolutely essential. It's not a thing for cars. It's not going to be a thing for planes.

With rapid charging infrastructure, you can top batteries up in 30-45 minutes to about 80%. That's for a high end car. Probably it could be done faster with specialized equipment. Typically, you don't drain the battery to 0% and you don't charge to more than 80% unless you are planning to fly to the maximum range. Finally, charging times are non linear and it slows down the further you charge a battery.

Also, people forget that airlines are on the ground quite long in between flights. Offloading and on-boarding passengers takes quite a bit of time. Programming the flight computers is quite fiddly. Running down checklists with dozens of items takes a lot of time. Waiting for engines to spin up and get to the right temperature, etc. 30-40 minutes is quite common.

Plenty of time to top up some batteries. And waiting a bit longer for some cheap electricity is probably well worth the tonnes (literally) of fuel you are not going to be burning.

rbanffy said 6 months ago:

That's right - the "non-stop" part is usually an hour at the terminal at least between landing and next takeoff. It's still a non-trivial amount of energy (the total expenditure of the flight) to be loaded into the battery. For the kind of range we are talking these days, that's more or less the same average rate the battery gets discharged during flight.

Swapping batteries would make more sense if we get to the point a full charge could allow a passenger plane to fly for many hours and charge speed would be limited by the total amount of power a terminal full of recharging planes would be requiring.

jillesvangurp said 6 months ago:

It depends. A lot of flights are around or below an hour and these include some of the busiest routes in the world. E.g. London - Dublin, all domestic flights in the UK, Germany, France, Spain, and other European countries and quite a few flights between those countries. Same for states in the US.

The Eviation Alice has a maximum range of around 600 miles. That's only a nine seater but it is going to be very disruptive in servicing anything between 100-400 miles. This kind of range you could take off with 80% charge and land with enough left for legal requirements and then top up back to 80% in about 45 minutes and maybe charge it to 100% overnight. That sounds like the sweetspot for this type of plane. It would likely be cheap enough to compete with e.g. cars on that distance and be way faster and possibly even be price competitive or close enough to make it interesting as an alternative to driving (at least from a cost perspective).

The Bye planes make more sense for smaller distances; perhaps as an air taxi in metropolitan areas. I don't think they are designed for longer distance commercial usage. Though obviously this is fine for GA type recreational flying. If you are flying those kind of routes commercially, you'd want to be able to do several flights between charging.

Over time, battery capacity, charging times, and ranges will improve. Also electricity cost is likely to benefit from on/near airport solar/wind as more planes are going to be flying electrical.

garethgriffiths said 6 months ago:

Electric planes have very few parts and are easy to maintain. The main cost of flying is fuel. Electric will make it a lot cheaper.

The battery as with all electric vehicles is still an issue, but for short air taxi distances it will be fine. Switch out the batteries on arrival and go again.

Reason077 said 6 months ago:

It's unlikely that switchable/swappable batteries will be a thing in aviation.

Even in the smallest aircraft, the batteries weigh hundreds - or thousands - of kilograms, comprise the bulk of the aircraft's dry weight, and are likely to be tightly integrated with the rest of the airframe for structural and safety reasons.

Most aircraft spend enough time on the ground between flights to make fast DC charging quite practical, and certainly much more so than swapping out huge batteries.

said 6 months ago:
PunksATawnyFill said 6 months ago:

Very cool. Now if we can keep corrupt local politicians from destroying our airports and turning the land over to developers (this means you, SANTA MONICA)... transportation might continue to advance.

jillesvangurp said 6 months ago:

Yes, you are right. Politicians have not realized yet that things are going to change. The main reason people don't like airports is pollution and noise. If you take that away, living close to an airport is actually quite nice since that means you can get in and out quickly.

Santa Monica and similar airports are going to be ground zero for this because they have lots of rich people living near by that might opt for an electrical plane. Sounds like an awesome way to get around LA, which has quite a few nice small airports.

Basically Bye and Eviation are launching products that are sort of hitting the sweet spot for general aviation. They have enough range that you can go somewhere at a small portion of the cost of a typical 100$ hamburger.

Probably in about a decade, there will be enough of these things flying that regulation and politics will adapt. Many airports currently have landing limitations because of noise. I could see some exceptions being made for electrical planes or even some airports being limited to only electrical planes. I could even see how building new airports could become popular again; especially close to cities and especially for VTOL planes (need a lot less runway).

cagenut said 6 months ago:

Most of the things you mention in your last paragraph are addressed in this talk, you'll probably enjoy it: https://www.youtube.com/watch?v=qGUrXCBB1OI

appleshore said 6 months ago:

Context: They’re closing Santa Monica airport and turning it into luxury condos and fine dining.

redis_mlc said 6 months ago:

Same with Reid Hillview in San Jose. Developers failed for years, then came up with the "leaded fuel omg" complaint, which worked. Nevermind the airport is adjacent to one of the the busiest freeways in the area.