[HN Gopher] Electric aircraft set to take flight by 2026 under n...
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Electric aircraft set to take flight by 2026 under new agreements
Author : fdalvi
Score : 150 points
Date : 2021-07-14 08:04 UTC (14 hours ago)
(HTM) web link (hub.united.com)
(TXT) w3m dump (hub.united.com)
| JasonFruit wrote:
| Note that they have agreed to buy them "conditionally... once the
| aircraft meet United's safety, business and operating
| requirements." The 2026 number in the title is probably without
| meaning. Nobody's meeting those requirements just yet.
| sandworm101 wrote:
| >>Nobody's meeting those requirements just yet.
|
| Someone is. What is very interesting about Harbour Air's
| approach is that they are not creating new aircraft but rather
| retrofitting electric propulsion onto their existing fleet.
| This is not an electric engine filling a niche application.
| Rather, this is electric _replacing_ combustion engines on very
| longstanding commercial routes.
|
| https://www.harbourair.com/harbour-air-magnix-and-h55-partne...
|
| "After the successful first flight of the Harbour Air eBeaver
| powered by magniX in December 2019 and the ongoing flight tests
| since then, the companies have teamed up with H55 to bring
| their shared vision of clean, efficient and quiet commercial
| aviation to life by 2022. H55 will provide its proven modular
| battery technology to expand the eBeaver's balance to weight
| ratio and endurance. The company's battery modules have one of
| the highest energy densities on the market and will provide the
| entire energy storage system and redundant battery monitoring
| at the cell level for the eBeaver. "
| VBprogrammer wrote:
| The eBeaver is about as relevant to conventional air travel
| as the existence of electric milk floats and forklifts was to
| ground transport for the past 50 years.
| sandworm101 wrote:
| I take it that you have never been to Alaska. Or BC. Or
| Washington. Or anywhere else with more trees than people.
| Without bushplanes the entire resource extraction industry
| would grind to a halt. The conversion of a Beaver to
| electric follows on the past turbo-beaver conversion. It
| matters and is being watched by the industry.
| minitoar wrote:
| Still has a ways to go. The eBeaver range is dramatically
| less.
| sundvor wrote:
| You've got to start somewhere, right? Kudos to the
| developers of this.
| epx wrote:
| In the 1990s, the idea of electric RC planes were
| ridiculed as well. I am moderately optimistic that 1:1
| planes will eventually follow, as RC electric cars became
| "good enough" and 1:1 electric cars are a reality now.
| sandworm101 wrote:
| I had an electric RC plane in the mid 90s. It wasn't
| much, just a styrofoam body and pair of electric motors
| (no flight controls) but it was a cheap and functional RC
| plane.
| dogman144 wrote:
| I was professionally close with an engineer who used to work on a
| (rapidly dwindling headcount) team responsible for the programs
| and related QA for mission critical flight safety systems. Think
| one of the big manufacturers.
|
| The eng dealt with:
|
| The standard was scripts with mutable variables such as `G == , B
| == , C == , redefine G as something else later` responsible for
| the processes around pretty critical airplane innards.
|
| QA down to 1 or 2 headcount, and those 1 or 2 also doing the
| above program writing.
|
| Zero hand-off once leaving the job on the mission critical QA the
| eng was responsible for, not for lack of effort on the engs part.
| Managers not aware the eng was leaving until day-of.
|
| I could go on and on, but the point: I'm not sure how I feel
| about the safety of airplane travel after the above, but at least
| the engines were internal combustion so somewhat tied to physics
| vs. programming logic. A future with electric airplanes scare me
| a bit though. The software in them is aggressively, poorly done.
| I know airplanes are designed w/ fail-safes on the fail-safes and
| that eng had their own limited view of a complex system. But, it
| was bad.
| IshKebab wrote:
| I would be shocked if modern turbofan engines don't have at
| least as much software in them as electric engines. Maybe more.
| whoisthemachine wrote:
| Most of your point is well made, but electric engines are just
| as tied to physics, unless I'm missing something? Doesn't mean
| quality of the control software is still not concerning.
| karagenit wrote:
| I think what they're trying to say is that the types of
| electric motors used in vehicles (like switched reluctance
| motors[1]) typically require a computerized controller that
| someone has to program, and therefore has an additional point
| of failure from a software standpoint.
|
| However, I'm pretty sure any modern internal combustion
| engine will have a highly advanced ECU computer too, so this
| is sort of a non-issue (though I'll admit I don't know much
| about aircraft engines specifically).
|
| [1] https://en.m.wikipedia.org/wiki/Switched_reluctance_motor
| dogman144 wrote:
| Ya poorly worded on my part.
|
| Gist is going from internal combustion with a ton of
| supporting or fully necessary tech to fully electric, fully
| SW-driven, really skeeves me out given the above
| testimonial and others like it.
|
| I openly allow it's quite possible that airplanes can't fly
| these days but for software though.
| aerospace_guy wrote:
| Modern turbofan/turbojet/turboprop (really, any engine)
| has a ton of SW involved. Engine controllers [1]
| literally control the engines. Your point is completely
| wrong, I've worked on this software and they go through
| many forms of verification for things to work. Look at
| the failure rate of avionics and compare that to other
| industries.
|
| Sure you or your friend may have had a bad experience at
| that company, but the big players generally won't let
| software bugs through.
|
| [1] https://en.wikipedia.org/wiki/FADEC
| dogman144 wrote:
| Eh,I did say it was only that eng's view of the world,
| but the big players certainly do let bugs through.
|
| Boeing code leaked in '20 [1] and it was ugly, however it
| was ~network vs. app layer so unclear how it worked at
| the engine level.
|
| Add in the track record of CAN bus security difficulties
| and knowing airplanes use similar tech, "generally won't
| let bugs through" when paired with the footnoted security
| leak is a gross overstatement.
|
| [1] https://www.wired.com/story/boeing-787-code-leak-
| security-fl...
|
| Before you write it off as an overhyped wired article, it
| was also a presentation at blackhat [2], so vetted by a
| fairly rigorous CFP.
|
| [2]
| https://i.blackhat.com/USA-19/Wednesday/us-19-Santamarta-
| Arm...
| whoisthemachine wrote:
| My assumption was modern ICE's also had software
| controllers. You could go with a fully hardware controlled
| electric motor (electric motors significantly pre-date
| computers!), but that of course would come with the same
| kind of trade-offs as fully hardware controlled ICE's (a
| couple I can think of off the top of my head are inability
| to change and inconsistent or degrading behavior over
| time).
| Tempest1981 wrote:
| Nova (PBS) had a show recently: https://www.pbs.org/video/great-
| electric-airplane-race-yija0... (requires member login)
|
| It highlighted a few Bay Area startups. Sounded like smaller
| commuter planes would be first. There were also hybrid designs,
| which reduced fuel use significantly.
| nazrulmum10 wrote:
| Breakthrough Energy Ventures is the leading voice of investors
| who are supporting clean-energy technology creation
| kragen wrote:
| This is unlikely to come to pass because batteries weigh
| something like 80x as much as the corresponding jet fuel:
| https://news.ycombinator.com/threads?id=kragen
|
| This means much less efficient flight, because lift costs energy,
| or much slower flight. But it's more plausible for these very
| short flights than for longer flights.
|
| Solar-powered synfuel seems like a more likely mass alternative
| for the near future (02030-02050).
| mustafa_pasi wrote:
| Digging through their website[1] trying to figure them out. Seems
| to me that the whole business proposition depends on their
| understanding that Norway, Sweden, (and I guess they expect
| others to follow) will mandate all short flights being electric
| in the next decade. They also say turboprops are higher
| maintenance and this expense reduces the viability of short
| flying routes, and I guess their implication is that electric
| will be cheaper. I am not sold on that one. 95% of the
| maintenance cost is the routine inspection. You'd have to do a
| routine inspection on electric propulsion as well. This is all
| just speculation until you see it in action.
|
| [1] https://heartaerospace.com/
| sandworm101 wrote:
| 95% of daily maintenance costs. Overhaul costs of jet/turboprop
| engines are considerable, several hundred thousand dollars per
| engine. A reasonable operating budget is about 1000$/hour per
| engine. Electric engines should avoid overhaul costs, and the
| fuel costs would be practically zero.
| HPsquared wrote:
| Gas turbine engines have critical components which can have
| gradual failure (fatigue particularly, and creep) which need
| regular inspection to catch small defects before they grow to
| critical size. They also have large numbers of high-
| temperature, stressed components.
|
| Electric motors are generally much simpler in construction and
| wouldn't need nearly as much mechanical inspection.
|
| The difficult/expensive part is the battery, but that's going
| to have more onboard condition monitoring and will be simply
| replaced periodically, not subject to regular teardown
| inspections. The cost of ongoing battery replacements might be
| significant, though.
| jcims wrote:
| This video from magniX shows one major advantage of electric
| aircraft:
|
| https://www.youtube.com/watch?v=RDtduvin9Mw
|
| There's almost nothing to inspect or maintain.
| aerospace_guy wrote:
| Huh? I see a lot of parts that can fail. What do you mean?
| kaba0 wrote:
| Compared to a jet engine that moves at high speeds under
| great pressure and heat?
| aerospace_guy wrote:
| For sure, you're right that compared to a jet engine there
| are fewer parts. The caveat is you're comparing a large
| engine (and aircraft) with a much smaller one. Electric
| aircraft of today can't go anywhere near the range of jet
| engine powered aircraft, and hence the engine sizes are
| similarly sized. It's not a fair comparison, but you are
| right.
| jcims wrote:
| Tearing this down for inspection vs. a turboprop, for
| example, would be a dream.
| aerospace_guy wrote:
| I agree! Just that saying "almost nothing to inspect or
| maintain" is not true.
| gunapologist99 wrote:
| 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-s...
| 908B64B197 wrote:
| 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 wrote:
| 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 wrote:
| 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 wrote:
| 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.
| NotSammyHagar wrote:
| I've been reluctant to get precheck because I hate to
| give up my fingerprints. There have been a few infamous
| mistakes where they messed up like the Oregon lawyer
| thought to be involved with the Spanish train bombers.
| Being in software, I know many immigrants to the us and
| they all have precheck and the border check version -
| while me and many of my natural born citizens don't have
| it, at least partly for that reason of fingerprints. I
| solved that problem for now by not flying during covid
| ;-) Am I unnecessarily paranoid? Probably.
| justaguy88 wrote:
| Applying for a US work visa or residency involves writing
| down so much about yourself (inc. getting fingerprints),
| that pre-check afterwards feels like just re-providing a
| subset of the same paperwork
| lifeisstillgood wrote:
| With all due respect, if they had built airports in the
| middle of cities, we would all be complaining about why we
| had to take a taxi to the train station miles from the city
| centre.
|
| The big advantage of the train is being on the property
| ladder 100 years early.
| tpmx wrote:
| Yeah, the amount of metro/central land railroads use is
| surprisingly huge.
| Symbiote wrote:
| Most cities that had relatively central airports have
| closed them (due to noise and pollution) and built new ones
| further out.
|
| Cities continue to build new railway stations and lines,
| usually underground, to improve access to the centre.
| legitster wrote:
| I think that the turnaround time is less important for the
| really small jets they are considering.
| mbreese wrote:
| 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 wrote:
| Small-market, heavily subsidized short-haul segments fly half
| empty, and have a low flight cadence.
| NickM wrote:
| 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.
| wtvanhest wrote:
| 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 wrote:
| 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.
| Tossrock wrote:
| 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.
| Hypx_ wrote:
| Because aluminum-air batteries are not rechargeable,
| they're fundamentally inferior to hydrogen fuel cells
| (which work in nearly the same way!). At least with
| hydrogen you can refuel the airplanes with a liquid instead
| of having to use a physical battery swap. Also, even higher
| energy density that doesn't gain weight during flight.
| throwawayboise wrote:
| Small tertiary airports often served by short regional
| flights don't have a lot of infrastructure. They have a
| couple of fuel trucks and a gate agent/security
| screener/baggage handler who might all be the same person.
| ars wrote:
| So instead of a fuel truck you have a battery swapper.
|
| You'll have to ship the batteries somewhere they can
| charge/reprocess, but you also need to ship fuel, so it's
| a 1-to-1 tradeoff (you can ship the batteries by land).
| EastLondonCoder wrote:
| Apparently Eviation is looking into aluminium air batteries
| https://en.wikipedia.org/wiki/Eviation_Alice
| otterley wrote:
| 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.)
| mapt wrote:
| There is no "recharging" an aluminum-air battery, you add
| the energy back through recycling (smelting) it.
|
| One of the big synergies is with renewables: With the
| right industrial process, you can treat this smelting
| process as a way to dump excess energy in peak production
| times.
| Hypx_ wrote:
| It's the same idea of green hydrogen. Only hydrogen
| allows you to use pipelines instead of physically hauling
| everything. You also don't have to worry about the
| battery physically gaining weight as you fly.
| Infernal wrote:
| 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
| throwawayboise wrote:
| 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.
| ars wrote:
| > Is this same energy needed to recycle the oxide from
| the batteries?
|
| The energy delivered by the battery in flight, is what
| you need to use to restore it back to fresh. The more
| energy you need the better your battery.
|
| Why does it need to be specifically solar? Use electric
| from the grid, and as the entire grid changes over to
| other power sources so will this.
| throwawayboise wrote:
| > Why does it need to be specifically solar? Use electric
| from the grid,
|
| The vast majority of grid electricity is still produced
| from fossil fuels (at least where I live).
| Infernal wrote:
| The real question here is the ratio of energy delivered
| over the life of a fresh anode as it is fully converted
| to aluminum oxide, to the amount of energy required to
| turn that same aluminum oxide back into a pure aluminum
| anode.
| hutzlibu wrote:
| "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 wrote:
| 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 wrote:
| I've always wondered about this, do electric cars charge
| each cell in parallel? or are there some series
| connections?
| Hypx_ wrote:
| 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.
| [deleted]
| romski wrote:
| Green aside, this was an interesting video explaining that for
| short flights electric planes are extremely lucrative
| https://youtu.be/aH4b3sAs-l8 [wendover]
| mch82 wrote:
| Is there a list of other YCombinator aviation startups?
| gamegoblin wrote:
| I recently had a pie-in-the-sky business idea and I would love
| for someone who knows more about the industry why it will
| definitely fail. I assume it's unworkable for a lot of reasons,
| but it is just plausible enough to be a fun idea for a sci-fi
| novel.
|
| Get a fleet of 2-4 seater unpowered glider planes [1]
|
| Get a bunch of rural properties spaced ~100km apart.
|
| Put little glider landing and launch strips on each property. Use
| a powerful electric winch to launch the gliders.
|
| Develop software that can fly the planes autonomously from strip
| to strip (I assume this is the really hard part, but I am under
| the impression that autonomous flying is a much easier problem
| than autonomous driving?).
|
| You now have the ability to shuttle passengers around your
| network of airstrips at ~200kph for the cost of electricity used
| by your winches and maintenance of the glider fleet.
|
| My thought is that the electricity of the winches is pretty
| minimal and could be served with some locally installed solar
| panels and batteries, and the maintenance is super low since the
| gliders don't have many moving parts onboard.
|
| The main use-case would be city-to-city short hops that are
| currently poorly served by rail. It's far easier to build a
| string of small airstrips than a whole rail corridor.
|
| This idea came to me when thinking about SpaceX's recent plans to
| catch their Starship boosters out of the air instead of having
| landing gear on them. The reasoning is that you can have
| essentially unlimited mass for ground support equipment, but mass
| on the booster is precious. So you offload the landing gear from
| the booster to the ground support equipment, even if it's big and
| complicated. This idea is like electric aircraft, but you've
| offloaded the propulsion and batteries to the ground support
| equipment.
|
| [1] https://en.wikipedia.org/wiki/Glider_(sailplane)
| ericpauley wrote:
| This has a lot of physical issues, not least of which is air
| resistance (drag). Simply launching a plane off the ground does
| not impart enough energy to make the full trip at high speed,
| and airplanes must continually burn fuel to counteract drag and
| gravity.
|
| Gliders are able to bypass this limitation in certain scenarios
| (such as updrafts) but this only works in specific cases. It
| also usually takes more than a launch to bring them to
| sustainable altitude, and they are slow.
| Leherenn wrote:
| A winch gets you maybe about 1/3 of the cable length (and thus
| strip length) at best. A typical cable length is between 1 to
| 2km long. Let's say you can gain 500 m height. A glide ratio
| around 50 is probably on the higher end of what's achievable,
| so you're looking at 25 km of range. That's before you account
| for wind, that the world is not flat or the fact that you don't
| start your landing at 0 m, but more like 200/300 m from the
| ground.
|
| Honestly, for short ranges, you're much better served by
| electric planes, or gliders with a self-launch motor. Small
| strips and winches don't go together.
| TheOtherHobbes wrote:
| You can get almost infinite range on hot days by riding
| thermals.
|
| This assumes thermals are available in the area (some days
| are better than others, as are some locations), and the s/w
| knows how to ride them.
|
| But that is a _much_ harder problem than just launching and
| gliding.
|
| Also, gliders that could carry even a handful of passengers +
| baggage would be huge, and likely far too heavy for a simple
| winch lift.
|
| As for the automation - airliner flight is more or less a
| solved problem, for flights in good weather that don't suffer
| any emergencies.
|
| It hasn't been taken further because most passengers don't
| want to fly without a human in charge. And also because the
| edge cases - unexpected turbulence, difficult weather,
| mechanical failures, unruly passengers, software failure -
| happen often enough to be a problem, and they need someone
| trained on board to take over.
|
| Otherwise people die. And that's very bad.
| rsp1984 wrote:
| Here's a simple test I use on startup ideas. I call it the
| reversion test.
|
| Let's suppose for a moment that air travel today worked the way
| you described it, with gliders, 60 mile range, electric winches
| etc.).
|
| Then someone comes along and invents the motorized plane and
| now all of a sudden you can start and land a plane pretty much
| anywhere you want, you're no longer dependent on weather and,
| in addition, you multiply your range by a factor of 5x to 10x.
|
| To me that sounds more disruptive than the other way around, so
| your idea would unfortunately fail the reversion test.
| zamadatix wrote:
| Not familiar but like the spirit of the idea. At first glance
| from just the material you provided it'd have to be a lot
| closer than 100km apart, 30:1-40:1 seem to be typical ratios
| with 70:1 being cutting edge and winch launch height seems to
| top out at 3000 ft (less than 1km). Not to mention for a lot of
| travel the ground isn't flat which can be problematic even in
| the direction there is an average decrease in ground height.
|
| Flying in good conditions may be an easier problem to solve
| than driving in good conditions but the issues seem to move
| towards what happens in the bad conditions. It's not like you
| can just hit the brake or park on the side of the road and
| continue later when the system detects a current or upcoming
| problem. Even if you get it so 99.99% of flights are in
| favorable weather and wind without piloting issue a 1 in 10,000
| chance your glider is going to make an emergency landing or
| worse is not good enough odds, especially if it's multiple
| flights each way. And that ignores the problem of the service
| being unavailable if certain weather conditions aren't met, so
| the backup transportation option is still needed at a moments
| notice in full force anyways.
|
| Then, much like self driving, there are the regulation issues
| https://www.ssa.org/glider-pilot-ratings/ which would be their
| own challenge to change and require you solve them before the
| business can even get it's chance to get going.
|
| That being said I like the concept, just not sure it's really
| any easier. Perhaps we should just build the missing rail
| instead :).
| gregmac wrote:
| > Develop software that can fly the planes autonomously from
| strip to strip (I assume this is the really hard part, but I am
| under the impression that autonomous flying is a much easier
| problem than autonomous driving?).
|
| As a software developer, this part is what I don't like.
|
| We're still quite a ways from fully autonomous driving cars (as
| in: don't rely on a human taking over for backup). A bad bug in
| an autonomous car could drive you at high speed into a wall,
| but there can at least be an "emergency stop" button that
| disables the main processor and jams on the brakes.
|
| Planes have no such ability to just "stop". At best, they could
| deploy a parachute, but even then landing safely is by no means
| guaranteed.
|
| I think we need a decade or so of fully autonomous cars being
| accepted into daily life before this can be attempted with
| anything that flies.
| topspin wrote:
| Point of information; certified autoland systems appeared on
| airliners in 1968. Yes, we're a ways off from the level of
| automation for a fully pilotless system as proposed here, but
| I think it a matter of a few years, perhaps a decade.
| jonfw wrote:
| You know what they say- the last 20% of the problem is 80%
| of the effort. I think that these percentages probably
| understate things, but the point is that getting something
| to be mostly functional in ideal circumstances really isn't
| much of an achievement.
| holycrapwhodat wrote:
| As both a software developer and a pilot...
|
| We're (much?) closer to Fully-Self-Flying planes than FSD
| cars because the problem space is - perhaps
| counterintuitively - MUCH smaller to tackle. And we have a
| lot more experience tackling it.
|
| Additionally there could easily be remote pilots as backup in
| case of catastrophe (See remote piloted military and border
| patrol UAVs)
|
| And pulling a parachute at 1000'+ altitude actually has quite
| a bit of precedent (See https://en.wikipedia.org/wiki/Cirrus_
| Airframe_Parachute_Syst...)
|
| Now... There's probably a lot of cultural and regulatory
| reasons why the "string of automated glider ports" idea will
| never come to fruition.
|
| But... As far as technical hurdles go, there's not much new
| technology that would need to be invented here.
| silvestrov wrote:
| > string of automated glider ports
|
| There is a small precedent here: the space shuttle flew
| almost 100% by computers.
|
| There was a small involvement of the pilots when landing
| and some change of software due to small RAM size in the
| computers.
|
| I could imagine "Fully-Self-Flying planes" would start out
| with cargo planes between areas with low population.
| theYipster wrote:
| As an industry leader on this specific subject matter... I
| agree: the problem space is much smaller, in theory.
|
| However, certification requirements and safety assurance
| needs will drive both cost and time into realizing fully
| autonomous aircraft. They will be here, but we are 10-15
| years away.
|
| The problem is in how to certify machine learning code.
| Today, you can't. Existing AMCs (accepted means of
| compliance) are incompatible with the nature of ML. (The
| breakdown is specifically with assurance architectures
| focused on code traceability and coverage.) A new
| architecture for demonstrating safety assurance with AI/ML
| is needed, and is being built, but is still 1.5-2 years
| away from being released, and then it will take another
| year or two before a CAA (civil aviation authority, like
| the FAA or EASA) will certify a component with ML code--and
| that will not be an autonomous pilot. That will come in
| time, but the industry is conservative--especially on
| safety-critical matters--and it will take years to develop
| trust in both technology, human factors, and methodology to
| work up to autonomously flown passenger aircraft.
|
| From the regulator perspective, EASA has taken poll
| position in thought leadership. Google their AI Roadmap or
| their Concept Paper for Level 1 Machine Learning
| Applications.
| decadancer wrote:
| >Develop software that can fly the planes autonomously from
| strip to strip (I assume this is the really hard part, but I am
| under the impression that autonomous flying is a much easier
| problem than autonomous driving?).
|
| I guess it could be easier in some ways, still the idea of
| passenger UAV(?) seems insane for some reason
| kaba0 wrote:
| Other than the already mentioned parts, wouldn't the
| acceleration be too great for your average passenger?
| gamegoblin wrote:
| On a 1km runway you could get up to 700kph with 3g of
| acceleration over 10 seconds. I think some rollercoasters
| pull higher G's than that.
| squeaky-clean wrote:
| Rollercoasters generally warn the elderly and those with
| heart conditions not to ride them. Commercial aircraft pull
| about 1.3 G maximum.
| kaba0 wrote:
| Oh, I imagined a much smaller runway -- of course longer
| ones could be more than good from this aspect.
| Izikiel43 wrote:
| Wouldn't landing be the hardest part?
| gamegoblin wrote:
| Totally possible, though I was under the impression that the
| UAVs used by the military already land autonomously. But I
| agree that the autonomous flight part is almost certainly the
| hardest part here.
|
| I am mainly curious if the general physics and economics of
| the idea are remotely feasible, assuming the software is
| solvable.
| jonfw wrote:
| UAVs are under constant supervision... when they say
| unmanned, they really mean that they're not lugging around
| the human who is manning them.
| TrainedMonkey wrote:
| I would expect handling all of the edge cases is the hardest
| part. For example, there is an emergency of board and you
| have to land immediately, what do you do?
| CPLX wrote:
| For context I have a pilots license and have tooled around in a
| glider a few times as well.
|
| Some problems with this scheme come to mind quickly but these
| are the first few:
|
| 1) Weather. It exists and basically makes this plan totally
| unworkable on any practical level.
|
| 2) Physics. An unpowered glider would have at best 1/100th the
| potential energy to fly distances like the ones you describe
| assuming perfect weather. Remember there are hard limits on
| altitude (due to oxygen) and speed (need to not rip the wings
| off) and those plus weight are the variables in your equation
| that tell you how far your glider can get unless it's able to
| exploit unpredictable thermals.
|
| 3) Refundancy, or lack of it. The failure mode for the
| slightest miscalculation is certain death for your passengers
| and maybe a few on the ground. Unpowered flight leaves
| essentially no margin for error which makes it a non-starter.
| amirhirsch wrote:
| Electric aircraft (not necessarily gliders) could use a
| tethered assisted take-off and ascent as a way to save on the
| initial power draw. You probably would want to use another
| assistant plane (not a ground station) to pull the passenger
| plane to altitude and speed and then return to a runway while
| the other continues on it's longer flight.
| skanga wrote:
| 1. Use it for CARGO only. Air freight is a huge business. 2. Do
| NOT fly in poor weather. Use it ONLY when conditions are
| favorable.
| azalemeth wrote:
| A few points:
|
| -- I don't know of any glider mass-produced after WW2 that
| seats more than two individuals, +- a water/sand ballast tank,
| +- a range-extender or self-launching engine.
|
| -- Have you ever experienced a winch launch? Try it. It's about
| 3g of acceleration, sometimes more. I quite like them. Most
| normal people probably wouldn't.
|
| -- At the top of the winch launch, you pretty much need to
| immediately find a thermal and gain some height before flying
| off cross country. You've got about a minute or two to do so,
| before entering the circuit and needing to re-launch and try
| again.
|
| -- Replace "200 kph" with "about 80 kt IAS". Remember that
| gliders fly beneath the weather 99.9% of the time and the winds
| in clouds are _strong_ -- although the only youtube videos I
| 've seen of an aircraft landing "backwards" on a runway are of
| a Russian high-wing aircraft, it's entirely plausible that you
| could end up getting a negative tack speed in a cloud.
|
| -- Cloud flying, or flying in inclement weather is _insanely_
| dangerous for a glider. They 're relatively light, have large
| aspect ratio wings, and don't usually have a whole lot of
| instrument navigation equipment on board. If the wings are wet,
| their coefficient of lift goes down...which would have very bad
| consequences for your business model. There's a reason that
| cross-country glider pilots have a friend with a land rover and
| a trailer, and train to land in fields, after all.
|
| -- You have absolutely no opportunity to make a go-around in a
| glider landing. Zilch. Nada. Screw it up and Plan-B is a well
| placed field. This is less likely to be acceptable
| commercially.
| carabiner wrote:
| The problem is rural areas are not cities by definition. So
| you'll drive out 30 minutes to a rural airstrip, fly out to
| another rural area in a 30 minute flight, then presumably rent
| a car in the rural area (build an Avis there I suppose), and
| drive 30 minutes to the other city. Including time for
| transitions, checking in, and paperwork, it's maybe 2-2.5 hours
| for 100 km of travel. You could maybe take rideshare, but if
| this is truly "rural" that might not be an option. Have you
| ever tried getting an Uber to take you 30 minutes outside of a
| city? I regularly drive such distances on the weekend in 1
| hour. The overall idea of travel between cities is what air
| taxis were for: https://en.wikipedia.org/wiki/Air_taxi but it
| was for distances of 200-500 miles.
|
| The energy would probably be better spent on a bus, with even a
| gas-powered bus being more efficient per passenger-mile than a
| 4 pax aircraft. It could also go city to city and skip the
| rural areas altogether.
| wongarsu wrote:
| Small aircraft on short routes are quite a niche market right
| now, but electric aircraft have a very good value proposition
| there, reducing both fuel and maintenance costs drastically.
|
| Depending on how things work out, in 10 years we might see a lot
| more flights in 10-30 seat electric aircraft, e.g. as connecting
| flights to tiny airports.
| username_my1 wrote:
| I mean in Europe all capitals are within 100s/1000s of km from
| each others... and inner country travel is definitely within
| the 100km range.
|
| This has a huge potential, but I don't know if it will improve
| overtime, since energy density of Li-ion is a hard limit.
| dillondoyle wrote:
| For me only if we figure out how to shorten airport time.
| Otherwise train in europe is easier - and usually located
| directly downtown or close instead of an hour in a car with
| traffic.
| mastax wrote:
| If someone gets a bomb on a train we'll figure out how to
| lengthen train station time...
| jeltz wrote:
| If? Spain has security checks on major train stations
| which makes it slower than in other countries but still
| way faster than airports. Trains have way more doors for
| example and it is easier to get a timeslot to leave than
| it is to get one to taxi.
| Robotbeat wrote:
| Small aircraft can operate from regional airport which are
| much, much faster to board and disembark from then the
| large airports that behemoths have to use. I really don't
| understand all the hate for a smaller electric aircraft.
| There are tons of advantages, and the difference in pilot
| labor costs are practically trivial. (I think a big driver
| for larger aircraft had been reducing number of engines per
| passenger as jet engines are expensive to maintain and the
| larger ones are also more efficient, but this isn't really
| applicable to electric motors.)
| marcosdumay wrote:
| In principle, smaller planes could have a shorten airport
| time and use a closer airport.
|
| I don't think it will happen, or at least that it will
| happen any time soon, but this is one problem that can be
| solved.
| canadianfella wrote:
| I mean.
| rcMgD2BwE72F wrote:
| We already have trains, you know.
| bertil wrote:
| Trains are great in many cases, but there's some limit to
| tunnels and bridges: you can go from Stockholm to Berlin
| directly, but Stockholm to Helsinki is harder (that's
| actually the destination that the plane is likely to
| cover); Manchester to Amsterdam is feasible by train in
| theory, but given the constraints around London and the
| Channel Tunnel, unlikely to loose its flight connection.
| Same for Aberdeen to Oslo.
|
| Many of those are over seas, so an ekranoplane would make
| sense, if you want to lower the energy output, but a
| tradition train won't work for many cases.
| fogihujy wrote:
| Helsinki - Stockholm has too many travellers for a
| 19-seater. :)
|
| Planes like this will most likely be used for routes from
| very small local airports to larger regional ones. I'd
| guess it's more likely to cover things like Ronne -
| Copenhagen, or Mariehamn - Helsinki.
| Robotbeat wrote:
| I wanted to love ekranoplanes, but although they have
| greater lift for a given span, they don't have superior
| lift to drag ratios, which is what limits efficiency.
| rjsw wrote:
| Manchester to Amsterdam is further than the distance
| targeted by these first electric aircraft, getting
| between a runway and a gate at Schiphol is probably
| beyond their range too.
| hutzlibu wrote:
| "ekranoplane "
|
| Can't they fly only over flat surface and very close to
| the ground?
|
| That makes them quite unpractical in my opinion.
| Robotbeat wrote:
| Every time someone points out how we "have trains already"
| it makes me think:
|
| It'll take less time to have operational electric passenger
| flights than it would to build a new high speed rail route.
| Particularly in the US (Europe is admittedly much better
| than the US in that regard).
| iagovar wrote:
| Trains take a lot more time, even HSR. I'm going to Madrid
| in the near future and I don't think I'll take a train,
| it's at least 6+ hours, and most of it is HSR.
| Milner08 wrote:
| How long is the flight in comparison? And have you
| factored in the airport time into that?
|
| I was looking at taking the Eurostar from London to
| Amsterdam, and a friend was dismissing it as it took 4
| hours where as the flight is ~45 mins. Except its not,
| the flight its self maybe 45 mins, but you have to get to
| heathrow (which is further away than St Pancreas) plus
| get there an hour early. Then we would have to deal with
| Schiphol and getting to the center of Amsterdam. To me
| the prospect of spending 4 hours sat down on the train
| and arriving directly in central Amsterdam, all the while
| with more space than a plane is much better than the
| prospect of 4 hours of that.
|
| Now obviously that's a very niche case, and for most
| people it doesn't make as much sense, but I think people
| get scared off by the long train times but ignore the
| extra time needed around the flight.
| choeger wrote:
| It also depends on train stations being accidentally
| close to where you depart/arrive. Most people don't live
| closer to a large train station then to an airport, I'd
| think.
| gspr wrote:
| Large train stations are far more common than large
| airports in Europe, so you got this the wrong way around.
| choeger wrote:
| How many of these train stations have been built after
| 1950? And what defines "large" in both cases?
| jeltz wrote:
| The train station in my city has 80 million travellers
| per year compared to the airport which only has 27
| million. And while I do not think many train stations
| have been built since the 1950s many have been expanded.
| iagovar wrote:
| ? I don't think so? Every large city has both a train
| station and a large airport.
| gspr wrote:
| I don't know what you mean by "large" then. In the
| context of this discussion, I meant train stations served
| by high speed rail and airports with regularly scheduled
| commercial service. The former _vastly_ outnumbers the
| latter in continental Europe.
| kaba0 wrote:
| Due to the nature of the two, train stations are usually
| in the center of cities, while airports have to be quite
| outside.
|
| Also, in my experience there are usually more than one
| train station in larger cities but even smaller ones have
| them. While airports are only a few even at a country
| level.
| dividedbyzero wrote:
| Definitely not in Germany. There are lots of medium to
| large cities without an airport, but every one has a
| large-ish train station with decent connections.
| Milner08 wrote:
| I dont think that's true at all. Train stations in Europe
| are far, far more common than Airports. You may have to
| change rather than a direct train, but chances are you
| can get around pretty easily.
| iagovar wrote:
| I don't know, but my city airport is small, so it's
| pretty much arriving and boarding. Now barajas is another
| history but I doub't ill be there for much more than 30
| mins.
| ClumsyPilot wrote:
| Small electric planes do not fly as fast as the current
| passenger Jets, theor speed is going to be comparable to a
| high speed train.
|
| In fact i'd say europe could avoid airplanes entirely if it
| could sort out it's rail network, but, alas, going from
| Londom to Prague I'd have to change like 6 trains. You have
| to cross many different national signalling systems, gauge
| sizes and ticket offices.
| iSnow wrote:
| Track gauge is the same all over western and central
| Europe. And Europe is slowly but surely moving towards
| ERTMS/ETCS( _) for train control. Different voltages and
| frequencies are a problem but less than in the past thanks
| to modern electronics.
|
| _
| https://en.wikipedia.org/wiki/European_Train_Control_System
| z303 wrote:
| Harbour Air in Vancouver are an example of that. Hopefully in
| service much earlier
|
| https://www.flightglobal.com/aerospace/harbour-air-to-resume...
| cpncrunch wrote:
| Update here: https://skiesmag.com/news/harbour-air-magnix-
| join-forces-h55...
| jillesvangurp wrote:
| Potentially they have about the same cost profile as a taxi
| over the same distance long term. Low noise also means access
| to smaller and more conveniently located airports. Initially,
| the novelty value will mean high demand, pricing, and
| relatively low cost compared to flying a small traditional
| plane. So great business opportunity if you can get a few
| planes.
| bamboozled wrote:
| Also consider that hangers are often huge and could be covered
| in solar panels making the electricity to charge the planes.
|
| Drastically reducing fuel costs.
| kevincox wrote:
| That seems irrelevant as that electricity could be collected
| and used whether or not it is used for planes. So while that
| may be a good idea it has little if any influence on whether
| or not it makes sense to use electric planes.
| dheera wrote:
| How much of their weight is batteries?
| thedrbrian wrote:
| Interesting that the routes they name are 119 and 78 miles. Kinda
| surprised Americans have flights so short. But then again the
| aircraft might beat CAFE for a vehicle with a single driver in
| it, plus aircraft usually carry a load of cargo too, as the
| passengers pay for the plane to go somewhere and the cargo is the
| profit. Wonder how much cargo this elegy plane can carry.
|
| https://en.wikipedia.org/wiki/Fuel_economy_in_aircraft#Commu...
| hu3 wrote:
| What's CAFE?
| GravitasFailure wrote:
| Corporate Average Fuel Economy. It's a regulation mandating
| fuel efficiency for vehicles.
|
| https://www.nhtsa.gov/laws-regulations/corporate-average-
| fue... is the full explanation.
| melling wrote:
| [Good] Rail travel in the United States is practically
| nonexistent and people are in a hurry.
|
| Hopefully low-speed maglev becomes a thing
|
| http://www.xinhuanet.com/english/2020-12/15/c_139591288.htm
| ZanyProgrammer wrote:
| It's 130 miles from Portland International to SeaTac, and there
| absolutely are a ton of Alaska Airlines flights between the two
| cities.
| apendleton wrote:
| True, but if you don't have a car and are going downtown to
| downtown, it's probably faster to take a train or bus, given
| that it takes almost an hour to get from downtown Seattle to
| SeaTac by transit and a shorter-but-still-nontrivial amount
| of time into Portland on the Max on the other end, plus
| ticketing, boarding, etc. I think it really only makes sense
| if you're connecting.
| kylehotchkiss wrote:
| It's all connecting to bigger flights. Plus 78-119 miles means
| either paying a lot of money for a cab, paying gas & parking
| fees for the duration of your trip at the bigger airport, or
| asking a friend/family member very nicely to take that trip to
| drop you off/pick you up. The smaller cities in question for
| these routes aren't going to have any sort of usable bus
| service for making a flight on time.
|
| To answer your cargo question: probably not much. The distance
| is within a normal delivery range of some rural UPS/Fedex/DHL
| routes. Making people in these smaller cities go to the airport
| to pick up boxes just makes a lot of work for them.
|
| source: my own experience taking loud proppy planes between
| Roanoke VA to Charlotte, NC to connect to a larger flight
| topkai22 wrote:
| Also there are a fair number of smaller cities that have
| physical obstacles (mountains, bodies of water) between them
| and a major airport. I used to fly with a connection between
| Chicago and Grand Rapids, MI regularly. That's a 50 minute,
| 220km flight, or a 3 hour 315 km drive (assuming no traffic).
| Plus, embarking/disembarking at a smaller airport lowers
| total time as well.
|
| I actually think you the cargo aspect will be somewhat
| significant as well- The regional airports I checkout on
| flightaware appear to have several fedex/UPS feeder flights a
| day.
| mason55 wrote:
| And it's usually much nicer checking in at the smaller
| regional airports. Less chaotic and shorter lines.
|
| Downside is that the services aren't usually nearly as good.
| kylehotchkiss wrote:
| And the two TSA agents only have an older X-Ray machine and
| no big backscatter machine to whisk the short line through!
| Aardwolf wrote:
| > Plus 78-119 miles means either paying a lot of money for a
| cab, paying gas & parking fees for the duration of your trip
| at the bigger airport, or asking a friend/family member very
| nicely to take that trip to drop you off/pick you up.
|
| How about trains for those distances?
| closeparen wrote:
| A small city would be essentially destroying its own
| airport by authorizing a convenient rail connection to a
| nearby bigger city's airport.
|
| Example: there is a train between Milwaukee and Chicago and
| it stops at MKE, but it will never stop at O'Hare, because
| that would be the end of MKE.
|
| Technically you can take the Blue Line from O'Hare to
| downtown, making dozens of local stops, and then walk a few
| blocks with your luggage to Union Station, but by the time
| you get downtown you could be in Milwaukee already on a
| connecting flight. And those few outdoor blocks are a big
| deal in winter, dragging soft sided luggage through the
| slush is not fun.
| freeone3000 wrote:
| No, this is America.
| bserge wrote:
| Track/engine building and maintenance is probably more
| expensive than airports and planes.
| GravitasFailure wrote:
| A a route that serves a few hundred passengers a day is
| also potentially profitable for an airline while a train
| would likely not be unless there's existing
| infrastructure that can be leveraged. Also, if nobody
| needs that route to be served any more, just send the
| plane elsewhere.
|
| Edit: I'm an idiot and missed that these are 19 seat
| planes. No, a train that only serves 19 people a day, one
| way, has a zero percent chance of being profitable, and I
| doubt it even makes environmental sense if you have to
| lay 70 miles of track to support it.
| choeger wrote:
| This. People tend to grossly underestimate the expense
| and effort to build new rail tracks in an industrialized
| country. Most land is owned by someone already, there are
| environmental concerns, other (rail-)roads and generally
| obstacles must be crossed, and -worst of all- you have to
| repeat the process basically for every single town you
| want to connect.
|
| Side remark: The same holds for roads, of course, with
| the notable caveat that roads form a flexible network
| automatically. Planes are just superlinear in their
| flexibility: If you have n airports and add one more, you
| get n new connections.
| dawnerd wrote:
| There used to be commercial flights from United from OXR to
| LAX. It's only an hour drive but they still managed to have
| service for quite some time and there's been talk about
| bringing it back. Little connector flights like that could help
| reduce congestion at LAX. I could easily seeing electric
| flights returning and even being subsidized.
| crossroadsguy wrote:
| Will one of the benefits be absence of copious amounts of highly
| inflammable liquid on it in the event of crashes?
| damsta wrote:
| Won't batteries be a problem now?
| aeternum wrote:
| Batteries could be used as part of the structure itself
| (similar to the transition we made from separate fuel tanks
| to simply putting fuel in the wings). That saves a lot of
| weight.
| zinekeller wrote:
| Good point. The Dreamliner has such problems in its Li-ion
| batteries to the point that the weight savings due to
| composite construction was subsequently nullified by metal
| retrofits to contain battery fires (https://en.wikipedia.org/
| wiki/Boeing_787_Dreamliner_battery_...). Additionally, IATA
| has put strict limits on Li-ion cargo due to Lithium being
| too reactive, so any plane with Lithium batteries must
| consider that.
| mastax wrote:
| It negated the benefits of the lighter _batteries_ , not
| the benefit of the composite airframe.
| tokai wrote:
| Probably even worse, as fuel can be dumped.
| gameswithgo wrote:
| you can dump batteries too
| 5555624 wrote:
| That could be more of a problem. Regardless of the
| height, dumping a battery means a projectile falling,
| which could injure someone or cause property damage.
|
| If fuel is dumped high enough, it pretty much evaporates
| and doesn't fall to the ground. If the plane is low when
| it dumps fuel, it can hit the ground and bystanders; but,
| it's not going do much, if any damage. (Assuming it
| doesn't hit someones barbecue or a smoker.)
| GravitasFailure wrote:
| Don't forget that lithium batteries tend to burst into
| flames if you hit them hard enough. Dumping your
| batteries can too easily become a bombing run.
|
| Also, Jet-A doesn't burst into flames like gasoline. Even
| if you soak an area with it, you don't have a firestorm
| just waiting to blow up.
| iSnow wrote:
| Not really, imagine a troubled plane bombing a city with
| huge and explosive battery packs.
| ThePadawan wrote:
| Isn't fuel generally only dumped because landing a (nearly)
| fully fueled plane exceeds the maximum landing weight of
| the runway?
|
| Or alternatively, if a plane develops a leak in one of the
| tanks, it can dump fuel to balance the weight.
|
| Is there a scenario where a plane in flight has its fuel on
| fire and dumping said fuel helps in any way?
| tacostakohashi wrote:
| No, lithium batteries are explosive. If anything, the fire
| hazard is probably worse.
|
| https://www.popsci.com/story/technology/electric-vehicle-bat...
| hellbannedguy wrote:
| Yea, they can drop fuel if they know there will be a problem.
| LinuxBender wrote:
| vs. ejecting batteries turns the aircraft into a bomber.
| The Air Force drop fuel tanks from some aircraft but I have
| no idea how much trouble they get into for doing that.
| [1][2]
|
| [1] - https://www.youtube.com/watch?v=oZfjyVbcJDI [video]
|
| [2] - https://www.youtube.com/watch?v=aXEyETZU8ag [video]
| spodek wrote:
| They talk about regional flight. Does anyone have any sign that
| battery-powered planes carrying a hundred people will cross the
| Atlantic, Pacific, or the U.S.?
|
| The physics in Tom Murphy's textbook
| https://dothemath.ucsd.edu/2021/03/textbook-debut suggests it's
| impossible. I've talked to people at electric plane companies who
| have offered no hope.
|
| I originally thought since we engineered from the Wright brothers
| to 747s, aren't we just at the Wright brothers stage now, but am
| starting to conclude it's not possible.
| macksd wrote:
| As others have mentioned, the energy density is a big deal
| because those planes' fuel accounts for A LOT of their take-off
| weight. To both illustrate this and point out another potential
| problem: when a fully fueled heavy, long-haul / high-capacity
| airliner needs to make an emergency landing shortly after take-
| off, one of the first things they do is start dumping fuel to
| reduce the weight (make it more maneuverable) and reduce the
| fire risk of a crash. Not sure what a comparable procedure for
| batteries might look like.
| FabHK wrote:
| An A380 at MTOM has about 15% payload (pax, cargo) and about
| 40% airplane, so a full 45% fuel. And kerosene has about 30
| to 90x the specific energy (energy per mass) as current
| batteries, so for an electric airplane the numbers would be
| much worse. (Plus the Airbus doesn't have to carry the fuel
| it has burned, while an electric plane does have to carry the
| empty batteries.)
|
| TLDR: Long range air travel with batteries is a long time
| off.
| busterarm wrote:
| Unless the energy density of batteries suddenly goes up 50x to
| meet avgas, then no it's extremely unlikely.
|
| Even with road vehicles, electric is only viable right now to
| the weight and load of your average 4-door sedan.
| SonicScrub wrote:
| The Youtuber Real-Engineering (aerospace engineering
| background) has a good video discussing the viability of
| electric aircraft. Barring some dramatic revolution in battery
| energy density, electric aircraft beyond a certain range are
| simply not-feasible. They are very feasible for short-range
| routes though.
|
| https://www.youtube.com/watch?v=VNvzZfsC13o
| topkai22 wrote:
| I think the caveat here is "battery powered electric
| aircraft." Fuel cells have much higher energy density IIRC.
|
| It's not inconceivable that fuel cell electric planes could
| become a thing as well, especially if these early BEV show
| other benefits around maintainability, noise reduction, etc.
| I think its a long shot though, as jet fuel + carbon capture
| will probably be price competitive before fuel cell airliners
| become a thing.
| benhurmarcel wrote:
| Fuel cell aircraft are very much a thing, and are being
| researched by the biggest companies in the industry.
|
| But they'd be called hydrogen aircraft rather than electric
| by most people.
| choeger wrote:
| I don't have such a sign, but 100 passengers is still smaller
| than what current jets do, so it _might_ be possible.
|
| It would be a radically more efficient design than what we
| currently have, though.
|
| Before we can even think of long-range flights, let's consider
| mid-range:
|
| A 737-300 has a range of ca. 4000km from 20,000l of fuel. But
| that's not flying with full tanks all the time. It has a
| payload capacity of 17t (on top of passengers, I think) and
| carries up to 149 passengers.
|
| If we cut the payload to 10t and passengers to 100, our
| "comparable" electric plane has 10t free payload for batteries
| (3t for the 50 passengers and 7t from the reduced payload). If
| we, generously, assume that we can add another 10t as
| "structural batteries" (basically, building the airframe out of
| batteries, because, why not, but also smaller and lighter
| engines), we end up with maybe a total capacity of 40t for our
| batteries (assuming 1kg/l for the jet fuel). We need the energy
| for a mid-range flight, say 1000km. That would be about 5000l
| of kerosene, in a 737 (not completely true due to weight loss
| during the flight). Fortunately, our electric propulsion is
| probably much more efficient (thermally) than a turbojet, so we
| might only need about 2/3 of the same energy. That puts us,
| very roughly, to the equivalent of 3.333l of kerosene, or about
| 86GJ. Hence our battery would have to offer 3.6MJ/kg.
|
| This is inside the theoretical realm of a zinc-air battery. So
| with this very rough calculation it does not seem to be
| impossible to achieve mid-range battery electric flight. And
| this usually means it is going to happen whenever it is
| economically sensible.
|
| For long-range flight, though, we would need even better
| batteries. Like, at least 4 times better. This is not on the
| horizon, currently.
| itsrajju wrote:
| Wendover Productions (who else?!) recently released a video[1] on
| the future of electric planes. Quite a lot of information in
| there!
|
| [1]: https://www.youtube.com/watch?v=aH4b3sAs-l8
| thunderrabbit wrote:
| Wow this video was indeed so great that I signed up for their
| sponsor mentioned at the end!!
| canadianfella wrote:
| Why "who else"?
| scrollaway wrote:
| I suspect it was in jest, but the reason why is that he is
| obviously immensely passionated about aviation and logistics.
| He makes really, really good videos about both, I'd recommend
| his channel to anyone.
|
| PS, I had to vouch for your comment to reply, as it was dead.
| Had a look through your profile... I think there's often a
| lot of value in asking simple questions, but a lot of your
| comment history is just extremely low value (eg. correcting
| people's spelling). If you don't have anything meaningful to
| add to a discussion, maybe consider not replying at all.
| itsrajju wrote:
| It was indeed in jest! Wendover's videos have been
| consistently increasing in quality over the years. The
| amount of research that goes into each one is phenomenal.
| So much so that lately if I ever come across any aviation
| topic on the internet, there's already a Wendover video
| about it. :)
| mastax wrote:
| I had a Gell-Mann amnesia moment when their video about
| electric car charge infrastructure made some major errors
| about electrical engineering. But their videos do
| generally feel exceptionally well researched, especially
| by YouTube standards.
| neither_color wrote:
| The only reason I pay for youtube premium is for creators
| like Wendover, Extreme Engineering, Smarter Every Day,
| etc. There are a lot of independent science, economics,
| and history channels there that are too good for YT but
| depend on the traffic for survival. Some have made
| attempts to switch to other platforms like Nebula but
| they dont have the mass yet.
| deregulateMed wrote:
| Anyone get a weird feeling about Wendover? I used to think he
| was a decent authority until I watched his channel Half As
| Interesting.
|
| Maybe he hires a writer, but his sarcastic joking nature comes
| off as extremely sincere and authoritative. This makes me
| question how solid his Wendover points are. He has a commanding
| voice and we believe him.
| citrusybread wrote:
| definitely. a lot of his other content is just kind of out
| there -- missing some critical details or glosses over other
| things.
|
| doesn't help that it feels like clickbait, at least for HAI,
| and most of them can be summed up with a tweet.
| saddlerustle wrote:
| LNA, an aviation industry newsletter, recently came to a very
| different conclusion [1]. The biggest difference to Wendover
| Productions's numbers is a hugely higher estimate in the cost
| of replacing the battery every 5-10 years due to battery
| degradation.
|
| [1] https://leehamnews.com/2021/07/01/the-true-cost-of-
| electric-...
| hokkos wrote:
| ridiculous quote of $/kWh of batteries, poor analysis of
| degradation which is way more complicated than they assume,
| also you should understand that soon carbon will have a
| price, airlines won't have a freeride forever
| thunderrabbit wrote:
| Thank you for bringing up this other conclusion. I still side
| with Wendover overall.
|
| Even if batteries have to be replaced that often now, the
| technology will continue to improve, becoming both cheaper
| and more reliable.
|
| Computers used to be the size of rooms and break due to
| literal insects in them.
| Robotbeat wrote:
| And it really depends on the chemistry. Some chemistries
| can last 10,000-100,000 cycles and so the battery may never
| need to be replaced in the life of the airframe. One thing
| short haul electric aircraft have going for them is the
| regulatory requirement to have a 45 minute reserve. That
| essentially means that the battery will never be cycled to
| anywhere close to 0% but probably maintain at least 20%
| almost all the time. Combined with most routes probably
| using just 80% of the max charge, and the batteries could
| last an extremely long time.
|
| Also battery prices continue to fall. Some industry
| analysts still use battery cost estimates from five or 10
| years ago for something that will happen in 30 years
| (battery replacement).
|
| Edit: looks like they're using extremely high costs for
| battery replacement, comparable to costs about a decade ago
| and about 2-4 times current costs for mass produced
| batteries, let alone 5-20 years from now: " The cost of
| replacing such a battery can be projected to reach around
| $400 to $500 per kWh mid-decade."
|
| Compare this to estimates/goals by the Department of Energy
| that say $60-80/kWh is feasible by 2030: https://pv-
| magazine-usa.com/2020/12/22/doe-offers-an-energy-...
| nradov wrote:
| The FAA regulations don't require just a 45 minute
| reserve. They need to be able to fly a missed approach at
| the destination airport, then fly to the alternate
| airport and land, plus still have a reserve.
| Robotbeat wrote:
| Sure, which increases the cycle life even more.
| FabHK wrote:
| A good rule of thumb (in general aviation at least) is
| that anything aviation grade is about 10x the "normal"
| price, or more.
| Robotbeat wrote:
| Fuel isn't. Jet fuel is basically no more expensive than
| diesel and sometimes cheaper (no road tax). You can
| consider batteries basically like jet fuel.
| fpoling wrote:
| In Norway jet fuel costs like 3 times less than gasoline
| due to absence of taxes. For these reason some amateur
| flight school use small planes with jet engines, like
| DA40NG, to get much lower operational costs. It can be
| even cheaper to fly such plane than drive a car.
| throwawayboise wrote:
| It's the same order of magnitude, but aviation fuel is
| more expensive than motor vehicle fuel (standards are
| higher for one thing).
|
| https://www.globalair.com/airport/region.aspx
|
| The chart linked above does not include additives which
| may be required such as anti-icing/anti-gel.
| IshKebab wrote:
| I don't think you can cite the technology that has advanced
| most dramatically out of all the technologies to support
| some kind of rule that _all_ technology inevitably advances
| rapidly.
|
| Yes they'll get better, but they might get 10% better over
| the next 20 years or something like that.
| [deleted]
| samatman wrote:
| I would say that the poster you're replying to is more
| directionally accurate than you are.
|
| I read them as saying "transistors have steadily marched
| toward the theoretical limit in size, batteries will do
| the same for power"-- and that isn't a 10% improvement
| from where we're sitting now. I couldn't tell you offhand
| what it is, but it's at least double density.
| mchusma wrote:
| Historical rate of improvement is significantly faster.
|
| 50% improvement in energy density over 10 years would be
| more conservative than most estimates, which range
| considerably but none I could find were worse than that:
|
| https://www.google.com/amp/s/thedriven.io/2021/04/28/how-
| ele...
|
| https://pubs.rsc.org/en/content/articlehtml/2021/ee/d0ee0
| 268...
| gok wrote:
| "The cost of replacing such a battery can be projected to
| reach around $400 to $500 per kWh mid-decade"
|
| By 2025 batteries are not going to cost 3x _more_ than they
| cost today.
| audunw wrote:
| That sounds like a ridiculous assumption. Airplanes are
| basically guaranteed to not discharge the batteries lower
| than 20% for safety reasons. I'm guessing they'll also not
| charge to fully 100%, like some BEVs. On fixed routes they
| could charge only what they need to get to where they're
| supposed to go plus the required buffer for emergencies. The
| batteries will probably also be cooled. So it could be an
| ideal scenario for battery degradation. There are 10yo Nissan
| Leafs on the road right now that was pretty much the worst
| case for battery degradation.
|
| You can also imagine that planes will start operating longer
| routes and then move to shorter routes as the battery
| degrades. Since the batteries are large they could get a
| decent amount of money for them when they're too degraded for
| airplanes. They should still be useful for energy storage.
|
| I also think it's likely that when airplanes go mainstream,
| they'll use a different chemistry than the standard Li-ion
| chemistries we have today. Maybe solid state lithium
| (Quantumscape?) or sodium ion. So it's very hard to say how
| big the degradation problem will actually be.
| cogman10 wrote:
| > they'll use a different chemistry than the standard Li-
| ion chemistries we have today.
|
| I somewhat doubt it. The characteristics that make a good
| battery for a plane make a good battery for a car. I think
| the only place there's a difference is airlines are likely
| willing to spend more on batteries.
| Robotbeat wrote:
| Sodium ion doesn't really have major advantages over
| lithium ion and is heavier. I am confident aircraft will
| use a lithium-based batteries. I agree some sort of solid
| state chemistry is likely. NASA is also working on solid
| state lithium battery chemistries for aircraft.
| Robotbeat wrote:
| The cost of replacing a battery is about the same cost as a
| turboprop engine overhaul, and depending on the battery type
| and other details, it may occur less often.
|
| Turboprop engines like the PT6 have a Time Between Overhauls
| of about 3000 hours, maybe longer. At 240 knots, that's
| 720,000 nautical miles between overhauls. If your electric
| aircraft has a range of 500 nautical miles and a 1500 cycle
| life, that's the same time. For an electric aircraft with a
| 900kWh battery like the Eviation Alice, and a cost per kWh of
| $170-$300/kWh, that's $150,000-300,000, the same as a
| turboprop engine overhaul.
|
| Cycle lifes well beyond that are feasible, though, and
| battery costs are reducing over time.
| yodelshady wrote:
| So, by that article, a fully-loaded turboprop (let's say 19
| 100 kg passengers, 4900 kg airframe, 320 kg fuel, 308 kg
| reserve fuel) flying 200 nm weighs ~ 7500 kg and consumes
| just under 4 MWh of fuel, of which 1 MWh is useful work.
|
| The battery model will weigh at least twice that for the same
| useful work, so _how the hell does it fly as far_? Could it
| actually fly the mandated 100 nm + 30 min contigency*
| oscardssmith wrote:
| One thing to consider is that you save a lot of weight on
| noise insulation. The wavy edges on the back of many new
| jet engines make the engines about 2% less efficient, but
| they let the plane save on enough weight to more than make
| up for it. Electric engines are probably about 20db quieter
| than equivalent power jet engines, so that can claw back
| some of the lost range.
| blendo wrote:
| Not unless they're using magical 1000-3000 Wh/kg batteries.
| I expect practical transports will use electric motors with
| hybrid power. And as far as I know, the ONLY electric
| airplane currently for sale is the two-passenger Pipistrel
| Alpha Electro.
| Proven wrote:
| Why the hell would anyone choose to take those instead of what
| works today?
|
| Oh, I see: chaeper ticket prices due to taxpayer-subsidized
| operational costs...
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