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.
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.
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.
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.
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.
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 :).
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.
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.
-- 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.
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.
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.
Also, gliders are not really able to handle emergencies that well since they are unpowered -- if there's a need to divert or something, they're completely at the mercy of their own gravitational energy. Gliders are usually very safe to fly in because they're very light and maneuverable, and crash-landings are usually OK. That safety net completely evaporates with thousands of pounds of human cargo.
I guess it could be easier in some ways, still the idea of passenger UAV(?) seems insane for some reason
They proposed stuff like putting steroids in water supplies to make Canadians stronger. One of their propositions was to build an inclined bike road across Canada so you could "coast from coast to coast."
I am mainly curious if the general physics and economics of the idea are remotely feasible, assuming the software is solvable.
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...
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.
They are swappable though: they explain that used battery packs can be replaced and that used packs can be used for a second purpose with less stringent requirements. For example, an energy storage facility at the airport.
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.
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.
The big advantage of the train is being on the property ladder 100 years early.
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.
If anything, these shorter routes are more time-sensitive.
Alternatively, maybe they could swap out the bottom of the fuselage or wings.
[1] https://leehamnews.com/2021/07/01/the-true-cost-of-electric-...
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.
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.
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*
By 2025 batteries are not going to cost 3x more than they cost today.
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.
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.
doesn't help that it feels like clickbait, at least for HAI, and most of them can be summed up with a tweet.
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.
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.
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.
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.
https://www.flightglobal.com/aerospace/harbour-air-to-resume...
Drastically reducing fuel costs.
https://en.wikipedia.org/wiki/Fuel_economy_in_aircraft#Commu...
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
How about trains for those distances?
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.
Downside is that the services aren’t usually nearly as good.
Hopefully low-speed maglev becomes a thing
https://www.nhtsa.gov/laws-regulations/corporate-average-fue... is the full explanation.
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.
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.
Even with road vehicles, electric is only viable right now to the weight and load of your average 4-door sedan.
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.
TLDR: Long range air travel with batteries is a long time off.
https://www.popsci.com/story/technology/electric-vehicle-bat...
https://www.youtube.com/watch?v=RDtduvin9Mw
There's almost nothing to inspect or maintain.
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.
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
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.
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. "
https://online-learning.tudelft.nl/courses/sustainable-aviat...
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.
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).
