23 ms·

This is kind of cool, but I'm skeptical that these sort of planes will ever be practical as much more than rich people toys. The power density of even speculat

This is kind of cool, but I'm skeptical that these sort of planes will ever be practical as much more than rich people toys. The power density of even speculative near-future batteries favors small airplanes and short flights. This doesn't really mesh into the existing aviation industry, so proponents of these small electric planes usually propose creating new markets entirely; e.g. Uber for Helicopters. But I'm pretty skeptical that laws will allow regular operation of these in residential neighborhoods for long, if at all. Also, where is the vertical stabilizer and rudder? I assume they're using differential thrust in powered flight, but what if they lose power? Can this plane be controlled in a glide?

toomuchtodo 4y ago
Enjoy the engineering achievement in the moment.
kurthr 4y ago
A lot of the electric (mostly fuel cell) aviation startup industry is funded/supported by currently profitable aviation companies. The 1000hp motors for them are, like the airframes, one of the mostly off-the-shelf elements of their development. I agree that even modern batteries are pretty absurd for any human scale flight, though scaling laws make smaller aircraft more reasonable.
- amelius 4y ago
  Isn't synthetic fuel much more promising?
  - jeffbee 4y ago
    Yeah they are, and this fact is just overlooked by people who aren't thinking through the implications of abundant renewable energy. With a surplus of renewable energy it makes much more sense to manufacture synthetic liquid fuels and burn them, than it does to power airplanes with batteries. The energy cycle is grossly inefficient but nobody is going to care because the energy inputs will be nearly cost-free.
    - frosted-flakes 4y ago
      I had that thought recently. Renewable energy sources like wind need a lot of energy storage. That is, unless you over-provision them so much that they can always meet demand even at peak times. This leaves you with over-production at other times, which could be used for other purposes that don't need to run continuously: synthetic jet fuel production, water desalination, etc. Basically, overprovision and then set electricity rates based on demand, and the renewable energy "storage problem" might just sort itself out. Of course, all those windmills and solar panels will cost an awful lot, so it might not be as simple as "overprovisioning".
      - Sebb767 4y ago
        > That is, unless you over-provision them so much that they can always meet demand even at peak times. Overprovisioning solar to power the grid on ice cold, windless new moon night is going to be hard. Having somewhere to put excess energy and some overprovisioning is always good, but it won't solve all storage problems.
        aftbit 4y ago
        If we can build a superconducting grid, we can transport power from the parts of the planet where it is sunny or windy to the parts where it isn't. Assuming that everyone remains friendly and operational, that is.
    - zbrozek 4y ago
      CAISO hits about 100gCO2e/KWh during the day. And I run a solar surplus that I don't put back on the grid. I'd be really happy if there were a good way for me to turn excess electricity into something I could use later. Maybe that's hydrogen. Maybe that's capturing carbon and putting it into liquid fuels. Maybe that's creating graphite that I can use for fun personal projects. But regardless, I don't expect grid electricity prices to fall. Probably not in the US. Definitely not in CA.
  - robonerd 4y ago
    From a CO2 perspective, synthetic fuels don't have an intrinsic advantage, unless you use biomass as your source of carbon. Traditionally, synthetic fuel has been made using coal or natural gas as the source of carbon. There is still some advantage to this, the nitrogen and sulfur content of the fuel can be dramatically reduced, which is great. But with regard to C02 specifically, you're basically burning coal. With biofuels, I think care needs to be taken to ensure we don't ruin the price of food for people by incentivizing farmers to grow fuel feedstock instead. Biofuels made from algae might be the best, since this wouldn't require the use of arable farmland. Another approach is to pull the CO2 straight out of sea water. Apparently the US Navy thinks this might be a viable approach, since their nuclear aircraft carriers have power to spare.
    - sky-kedge0749 4y ago
      I recently commented about synthetic jet fuel in another thread https://news.ycombinator.com/item?id=31704829 https://news.ycombinator.com/item?id=31704829: > A problem with biofuel is scaling it up, see: https://ieeexplore.ieee.org/document/7498153 https://ieeexplore.ieee.org/document/7498153. According to that article the U.S. would need to devote "an area bigger than Texas and California and Pennsylvania combined" to crops specifically for its own jet biofuel needs. That's just for flying, not for food or fuel for ground transportation or anything else. Also that article says that from 2009-2013 a $100 million effort was made to figure out how to get sufficient synthetic fuel from algae but they eventually gave up and went back to the drawing board.
      - ncmncm 4y ago
        Biofuel is an obvious dead end. The future has no place for biofuel in any substantial amount.
        trashtester 4y ago
        Ethanol made from food (like corn) is a dead end. Firewood and derivatives have always had an important place in heating and cooking, and are likely to continue in that role for a while. Other types of biomass based hard fuels (from recycled garbage/waste, algae, etc) will most likely also play a role in electricity production and heating, but perhaps a small one (unless algae based biomass takes off). And for liquid fuels for transportation use, algae may also end up being a competitor to hydrogen when oil runs out. I remember there were a lot of companies working in that space 10 years ago, but then there was the oil price crash in 2015, and it seems many switched away. For instance algenol was positioning itself as a fuel company, but appear to have diversified: https://www.algenol.com/sustainable-products/?category=ndustrials https://www.algenol.com/sustainable-products/?category=ndust... If oil prices remain at current levels, though, algae may be only a few years away from scaling up to take a significant part of the market.
  - hannob 4y ago
    There's been an EU funded research project that did some projections on the electricity needed for e-fuels. See the graphic on page 44: https://www.fch.europa.eu/sites/default/files/FCH%20Docs/20200507_Hydrogen%20Powered%20Aviation%20report_FINAL%20web%20%28ID%208706035%29.pdf https://www.fch.europa.eu/sites/default/files/FCH%20Docs/202... For pure e-fuels they project 32 PWh. That is, to put it in perspective, more than the total world electricity production today. You'll want to use every technology available to do this in a more efficient way - batteries for very short ranges, hydrogen for mid ranges, e-fuels only for long range where nothing else works. It'll still be very challenging and likely the current growth projections of the aviation industry will be seen as unrealistic fantasies at some point in the future.
    - lukeschlather 4y ago
      > For pure e-fuels they project 32 PWh. That is, to put it in perspective, more than the total world electricity production today. Total annual electricity production is 161 PWh. THe PDF you linked puts it in perspective by saying that if it were purely powered by renewable energy it would increase the size of the renewable energy sector by 3 to 5 times. In other words this doesn't sound hard at all from an electricity standpoint. If electrical generation were half the cost it would be economical right now.
      - moby_click 4y ago
        From https://pubs.rsc.org/en/content/articlelanding/2020/se/c9se00479c https://pubs.rsc.org/en/content/articlelanding/2020/se/c9se0... > We find that an electricity emissions factor of less than 139 g CO2e per kW h is required for this [Direct Air Capture system paired with Fischer–Tropsch synthesis] pathway to provide a climate benefit over conventional diesel fuel. The grid averages in most regions are higher than that. I don't think multiplying current renewable generation just for jet fuel is easy.
  - bbojan 4y ago
    Burning any fuel in our atmosphere produces nitrous oxides. Synthetic/carbon neutral fuels won't help with that.
    - SoftTalker 4y ago
      These can possibly be addressed by catalytic converters in the exhaust (not sure how feasible that is in a turbine engine though). In any event, it's a small fraction of total greenhouse emissions, dwarfed by CO2. Let's not let perfect be the enemy of good.
      - bbojan 4y ago
        Oh I wasn't concerned about their greenhouse effect contribution. NOx can cause asthma and bronchitis and can aggravate pre-existing heart conditions. They also form smog. Did I mention that they are bad for the ozone layer?
ramesh31 4y ago
>This doesn't really mesh into the existing aviation industry, so proponents of these small electric planes usually propose creating new markets entirely; e.g. Uber for Helicopters. But I'm pretty skeptical that laws will allow regular operation of these in residential neighborhoods for long, if at all. I can see it becoming more of "Greyhound for Helicopters". Practically every town in the US greater than a few thousand population has at least a local municipal airport. With electrification, aviation can become so cheap that all of these fields will just have a few commuter size electric aircraft that feed into to the rest of our existing airport infrastructure. And with the planes being so small, there's really no need for TSA security or anything, it becomes as simple as buying a ticket on your phone and hopping on the plane like a bus.
- 908B64B197 4y ago
  > And with the planes being so small, there's really no need for TSA security or anything There's no need for larger planes either for zero-risk travelers.
  - deleted 4y ago
    [deleted]
- akira2501 4y ago
  Granted, this is a new type of transport.. but the current metrics on air flight safety do not support this idea. Take offs and landings are the most dangerous part of flight, and still account for planes being more dangerous _per trip_ than most other modes of transport. Planning to create a plane that fills this space is planning to create a plane that suffers a lot of accidents for almost no real gain over current options. Buses are incredibly safe. If you want better busses, build those instead. This obsession with floating to your destination above the ground does not seem wise or worthwhile.
  - ghaff 4y ago
    It's trivial to create a luxury "bus" in just about any form factor you want to from a full-size motor coach down to a limo. Presumably the economics don't work in most cases. Of course, if you're talking small municipal airports in the US, the vast majority of people living there, especially those who can afford somewhat upscale transportation, probably own a car.
rklaehn 4y ago
The energy density of gasoline does not matter at all. Batteries are good enough for some applications, like short distance flights. And the operating costs for use cases where batteries work strongly favour batteries. Power density has not been a problem for a while. We are not anywhere near the theoretical limits of battery energy density. So as soon as there are some commercial applications for battery powered flight, there will be a strong economic incentive to get closer to the theoretical limits. Current jet engines are absolute engineering miracles that go very close to the physical limits to get maximum efficiency. But it took several decades to get there.
- whatshisface 4y ago
  There is already a lot of economic incentive for lighter batteries.
  - rklaehn 4y ago
    Yes, and they are improving by a few percent every year. No major breakthroughs, but compounding improvements year over year, which do add up. Batteries have improved incredibly in my lifetime. As a kid I had an electric RC plane that barely made it off the ground. Now you can get pretty cheap aerobatic RC planes that easily compete with gasoline powered models. Battery powered screwdrivers used to be incredibly underpowered. Now I have a very decent battery powered rotary hammer... https://cdn.arstechnica.net/wp-content/uploads/2021/05/bnef_e_density-1440x810.jpg https://cdn.arstechnica.net/wp-content/uploads/2021/05/bnef_...
- robonerd 4y ago
  > The energy density of gasoline does not matter at all. Well if we're talking about commercial aviation, we're talking about jet fuel not gasoline. Regardless, it obviously matters a lot. A fully loaded 747 freighter has somewhere around 200 tons of jet fuel and a max payload of about 130 tons. They already need more fuel than cargo, and that's with the excellent energy density of jet fuel. Furthermore, traditional planes get lighter the longer they fly as they burn off their substantial fuel loads. The last 20% of the fuel goes a lot further than the first 20%. Batteries don't get this advantage at all. (Dropping batteries from the plane with parachutes is a terrible idea, but I've lost count of the number of times I've seen it proposed..) > We are not anywhere near the theoretical limits of battery energy density. This doesn't jive with what I've read. It's my understanding that we're already near the limits of what electrochemistry can give us, and future advancements are likely to come from improved electrode designs, with maybe 2-3x better performance possible if we're lucky.
nradov 4y ago
Powered lift aircraft are not controllable in a glide, nor are they capable of autorotation like a helicopter. Any complete loss of power will result in an unrecoverable spin. For safety these aircraft rely on redundant systems, plus a parachute. Finding landing sites is going to be a major challenge even if they can solve the battery problems. New York City could be a prime market but there are only a few heliports. Politics and safety issues make it difficult to construct more.
- bluejekyll 4y ago
  Any idea what the minimum height for the parachute to be effective as a life saving device?
  - jeffbee 4y ago
    The Cirrus SR22 needs ~1000ft above ground to effectively deploy the airframe parachute in a spin.
  - nradov 4y ago
    Minimum effective altitude for parachutes on light aircraft is about 400 ft agl, but the exact number varies depending on the flight regime. For powered lift aircraft there is likely a small "dead zone" in the flight envelope: too high to survive a crash, too low for the parachute to be effective. This may or may not be acceptable depending on mission risk tolerance and the reliability of other systems. https://www.aopa.org/news-and-media/all-news/2018/march/flight-training-magazine/how-it-works-airframe-parachute https://www.aopa.org/news-and-media/all-news/2018/march/flig...
    - GordonS 4y ago
      > too high to survive a crash, too low for the parachute to be effective This is probably a silly question, but couldn't the pilot just wait until the plane dropped below the dead zone before deploying the parachute?
      - 4y ago
Simon_O_Rourke 4y ago
I'm guessing that if it loses power during flight then it's curtains for the airframe and anyone unlucky enough to be in it. There's lots more work to do to push it out to the mass market, but I could definitely see a niche for it.
- themitigating 4y ago
  That's the same if a jet engine losses power
  - p_l 4y ago
    Nope. Look at the tiny wings, and at what speed it still depended on vertical thrust. It's going to have horrible glide ratio, which means unpowered landings might be, well, not a thing, which leaves you only with emergency full-plane parachute as an option. Pretty much all jet engine planes can do unpowered landings in glide, though admittedly some have pretty high speeds involved - but then they operate by default only on airports that have facilities for such speeds.
    - oliveshell 4y ago
      See this famous example, where a jet airliner ran out of fuel in flight and glided to a successful landing: https://en.wikipedia.org/wiki/Gimli_Glider https://en.wikipedia.org/wiki/Gimli_Glider
      - kayodelycaon 4y ago
        Also Air Transat Flight 236. https://en.m.wikipedia.org/wiki/Air_Transat_Flight_236 https://en.m.wikipedia.org/wiki/Air_Transat_Flight_236
  - sokoloff 4y ago
    If a [civilian] jet aircraft loses an engine, it's still a strong favorite to end that flight upright, intact, and on a runway. There are a couple dozen jet engine failures per year; the overwhelming majority end up in a safe conclusion. https://www.cbsnews.com/news/jet-engine-failures-rare-usually-not-fatal/ https://www.cbsnews.com/news/jet-engine-failures-rare-usuall...
dkasper 4y ago
Zero chance of helicopters in cities after 9/11. You can’t fly helicopters over SF or Manhattan anymore except for medical purposes.
- JumpCrisscross 4y ago
  > can’t fly helicopters over SF or Manhattan Both cities have plenty of potential even with overland banned. New York has a thriving helicopter business between boroughs, up and down both sides of Long Island and to and from the airports. The Bay Area isn’t similarly knitted together, but there is no good argument for not having an electric hop from e.g. Mountain View to SFO.
  - CoastalCoder 4y ago
    Can someone comment on why the parent would be (as of this writing) downvoted? I'm wondering if there's some context I'm missing.
    - hef19898 4y ago
      Best guess? Because the helicopter restrictions have nothing to do with 9/11.
  - woodruffw 4y ago
    Worth noting that the "thriving" helicopter business is uniformly disliked by residents, due to noise pollution[1]. [1]: https://www.nydailynews.com/news/politics/new-york-elections-government/ny-nyc-lawmakers-target-manhattan-helicopter-noise-complaints-20220515-uddcc42wsjctlmvoxg5cqr2ipe-story.html https://www.nydailynews.com/news/politics/new-york-elections...
- mlyle 4y ago
  Helicopters aren't banned over Manhattan, etc, despite repeated efforts to do so. In the late 1970's, all the building-top helipads stopped operation after repeated accidents. Still, there's the helipads along the river and a VFR corridor in and out of Manhattan. In 2009, the altitude rules for the corridor got a lot stricter because of repeated fatal accidents.
marcosdumay 4y ago
The low energy density of batteries favors large planes and short distances. The only reason you are seeing them in small planes is that electric propulsion makes VTOL viable, and VTOL favors small planes. There is just this niche in aviation that can't be filled at all by fossil fuel engines, so it's the first to adopt electric ones. And yes, regulations will be the most important factor for those. I imagine it all depends on how silent those planes can be. But I doubt safety will be the limiting factor.
- closedloop129 4y ago
  In that niche, why are batteries needed? Couldn't those planes be constructed with gas turbines that generate the necessary electricity?
  - t0mas88 4y ago
    VTOL works fine with turbines, nearly all large helicopters use turbine engines. They don't use the turbines as generators but instead connect both engines to the rotor via a gearbox.
  - marcosdumay 4y ago
    It's a matter of the weight/power relation. While batteries suck on weight/energy, their weight/power is great. The lower that relation, the smaller you can make your VTOL vehicles, and the smaller the vehicles, the cheapest and more economical they are on total.
- dr_dshiv 4y ago
  > I imagine it all depends on how silent those planes can be. I agree. I’d say, though, not just how silent, but how pleasant sounding. Aesthetics of sound could make or break this industry.
  - inb4_cancelled 4y ago
    You either get a chop-chop-chop, or a bzzzt, both incredibly loud. It's not the engine that makes the noise, it's mostly the propeller/rotor. The only advantage of electric VTOLs is easier manufacturing and better control.
scythe 4y ago
>[The electric airplane] doesn't really mesh into the existing aviation industry The reason small electric planes haven't taken off [1] is that they simply haven't proven their cost advantage. About one-sixth of the cost of a flight is fuel, which can be difficult to tax because of jurisdiction shopping. A third is labor, including taking care of the plane. Seven percent goes to building the plane. From: https://www.travelandleisure.com/airlines-airports/airfare-dollars-breakdown https://www.travelandleisure.com/airlines-airports/airfare-d... Optimistically, electric planes could be cheaper to fuel, build and maintain. That's enough to upset an entrenched industry. But it's not clear how it should be organized, and the infrastructure mostly doesn't exist. Plus, the scale you expect to operate at depends on battery technology, which has been a little up in the air [2], and you don't want to design your operations around 1000-mile ranges if it's going to be 2000 in ten years. 1: Sorry. 2: Sorry. But see: https://www.nature.com/articles/s42004-022-00626-2 https://www.nature.com/articles/s42004-022-00626-2
- ur-whale 4y ago
  There's other aspect than the pure economic aspect: Noise VTOL When both are combined, this makes Urban flight closer to feasable.
cesarb 4y ago
> The power density of even speculative near-future batteries favors small airplanes and short flights. This doesn't really mesh into the existing aviation industry, How short are these short flights? The hugely popular Ponte Aérea (https://en.wikipedia.org/wiki/Ponte_A%C3%A9rea https://en.wikipedia.org/wiki/Ponte_A%C3%A9rea) has a flight duration of one hour.
- robonerd 4y ago
  That flight is about 230 miles (365 km) as the crow flies, and they're doing it with 737s that seat 100+ each and fly dozens of these flights a day. Compare that to this battery plane that can fly 200 miles: https://cleantechnica.com/2020/01/29/rolls-royce-claims-its-latest-electric-airplane-battery-has-the-highest-energy-density/ https://cleantechnica.com/2020/01/29/rolls-royce-claims-its-... These aren't in the same ballpark; they aren't even playing the same game. If you want something to replace that plane route, I suggest buying a lot of buses.
DennisP 4y ago
It used to mesh a lot better, when general aviation was much bigger than it is now and we had lots of tiny airports. Maybe we could get back to that. VTOL makes it a bit easier.
- nradov 4y ago
  If you have even a tiny airport with a real runway then you can operate fixed-wing aircraft (possibly electric powered) without the extra cost and risk inherent to VTOL. Lillium and their competitors in the e-VTOL space are trying to create a new market for urban air mobility by bypassing airports and building new heliports, but even if they can solve the technical and legal challenges it's unclear if the economics will work.
kkfx 4y ago
This might give you some insights... https://www.easa.europa.eu/sites/default/files/dfu/uam-full-report.pdf https://www.easa.europa.eu/sites/default/files/dfu/uam-full-... ...of the idea. Witch is essentially, advertisement aside, "the wealthy who happen to live nearby cities, witch happen to be open-sky prisons^w^w factories stuffed with services to achieve the Chinese lockdown with workers who live in the factory, to work, of course ehrm, to achieve the best work life balance (better not say the best to who) can came and go from such erh smart cities in full comfort with means that made things closer, like if they live inside the city and goes with cars. ...In the LONG term, that means we can benefit from the economy of scale living "near" but far less dense than today so at that point in time we have finally found a way to live sufficiently flexible to withstand the technological, social and climate change still being near enough to be social and have economy of scale phenomenon. Or: in the short term we need a good solution for those who can pay, in the medium terms slaves ahem citizens have built a new society and new generations will finally benefit from such progress... In theoretical terms: maintaining roads network is expensive, far expensive if we also need to build new ones, like a potential future arctic "anthropization" due to climate change, so better made few railroads and waterways for heavy loads transports and live humans in the air, far more flexible and cheap. At a certain point in time if we are still alive as a species we will reach that point. Then the "self-sufficiency push" will be the key to reach that goal in an unspecified future. Ps if they loose power there is AFAIK only an emergency parachute for the entire plane. Only it demand, I suppose, a certain altitude to being able to be deployed...
newaccount2021 4y ago
momenti 4y ago
Lilium's plane has 30 engines, multiple independent battery packs, and electric motors are way more reliable than jet engines (due to being so much simpler). A Lilium plane may have a 1000x higher chance of a crash in case of full engine failure, but perhaps that can be compensated for by 1000x times simpler/redundant propulsion technology. This seems to be very hard to assess in theory, so we probably just have to wait and see how it performs in practice.
- leoedin 4y ago
  That's all very well, as long as there's no common modes of failure. Redundancy can be a means to achieve reliability, but not always. Imagine the cause of failure is a bug which kicks in at a specific time of day, or an integer overflow which happens after a certain amount of uptime, or all the motor drivers are susceptible to a specific RF frequency. It doesn't matter how many motors you have if they're all susceptible to the same failure mode.
  - hef19898 4y ago
    That's what certification is there for, isn't it?
  - mbreese 4y ago
    > integer overflow which happens after a certain amount of uptime It’s not just electric powered planes that have to worry about such things… this was an issue for the Boeing 777 Dreamliner too. If it was powered on for longer than 248 days, it could lose all electrical power due to an overflow in the generator. https://www.engadget.com/2015-05-01-boeing-787-dreamliner-software-bug.html https://www.engadget.com/2015-05-01-boeing-787-dreamliner-so... I’m not saying it isn’t a concern, but rather it is a concern for all planes (and vehicles for that matter). Many commercial passenger planes are now fly by wire. If you lose electrical power, you’ll also lose control. So, while we’re talking about purely electric planes, the problems are universal.
    - coreyisthename 4y ago
      But many planes can glide to a certain degree. This thing would just fall or glide with zero pilot control. No control surfaces.
ben_w 4y ago
I can’t possibly comment on any specific design, but what I’d like is something that can replace road ambulances. This is partly because I live right next to a busy crossroads and often get multiple simultaneous sirens; but I do also wonder how faster they can arrive by going as the crow flies rather than following street layouts, and how much they have to slow down both for traffic and for blind corners.
- jlmorton 4y ago
  This is one of the primary reasons I've bought into the eVTOL revolution. I'm also skeptical about these filling city skies, due to safety, noise pollution, etc. But the market for emergency and special purpose vehicles alone is enormous. The US market size for existing _air_ ambulances is itself $4.5 billion dollars annually. The market size for standard ambulances is nearly 10x that. When you expand this to the rest of the world, you can easily see a 100+ billion market for these sorts of vehicles, whether in ambulance services, firefighting, agricultural, or any number of other activities. It's still possible we develop near-to-city eVTOL airport systems for short distance travel. But even absent that, I still think there's a big market opportunity.
- SoftTalker 4y ago
  For critical patients helicopters are already used. For patients who need to get to a hospital but are short-term in stable condition, is the extra expense of an air ambulance justified, in a health care system that is already unaffordable?
  - wolverine876 4y ago
    > For critical patients helicopters are already used. I'm sure they are used based on a cost/benefit calculation - not everyone gets them. If eVTOL reduces the cost, many more can benefit, or those funds can be shifted to something else.
  - ben_w 4y ago
    The ability to replace road ambulances is, I think, inherently a cost claim. After all, capability is already solved with, as you say, helicopters.
dzhiurgis 4y ago
Dropbox vs rsync moment right here
theptip 4y ago
This was posted on HN a while ago; of course the numbers are aspirational but this explains their business model: https://lilium.com/newsroom-detail/why-regional-air-mobility https://lilium.com/newsroom-detail/why-regional-air-mobility > If we imagine for a moment that you work in an office in Palo Alto, you could now choose to live in Hayward (5 min flight, $25), downtown San Francisco (10 min flight, $50), or even San Rafael (15 min flight, $70). > Or maybe you want to escape to Lake Tahoe for a long weekend? That would be less than an hour on a Lilium Jet, at a cost of around $250 at launch and less in the near future. It might not be something you’d do every weekend, but saving you three hours each way might well make it worthwhile for an occasional trip. Obviously at first this will be a luxury good, but it's not obvious that it'll remain out of reach for the middle class. (Sure, it'll never be cheaper than a bus.) It's a fair question exactly how much regulatory change this approach requires, but my impression is that they are trying to operate within existing constraints (I'd appreciate any insight from experts in the aviation space though).
- bufferoverflow 4y ago
  You would have to be making a lot of money to justify 2 such flights per day. 25 * 2 * 22 = $1100/mo = $13.2K / year.
  - mbreese 4y ago
    But if you can live in a cheaper place than Palo Alto, you’ll make back that $15K per year in lower house payments. And if you only have a comfortable commute of 15-20 min each way as opposed to an hour (or more), your standard of living will be much nicer too.
    - duhast 4y ago
      House prices will adjust once air taxis take off (no pun intended).
    - theYipster 4y ago
      Perhaps not. A recent study (can't remember where, but industry specific) proposed that EVTOL economics--at scale--will settle at a CASM of $3. (CASM = cost per available seat mile. Note RASM, or revenue per available seat mile, will be higher or these businesses won't make a profit.) With a CASM of $3, this study showed that only 0.03% of the Bay Area will be wealthy enough to commute on these vehicles on anything resembling a regular basis.
bozhark 4y ago
Air taxi is their market
clouddrover 4y ago
> The power density of even speculative near-future batteries favors small airplanes and short flights. Use a hydrogen fuel cell instead: https://www.bbc.com/future/article/20210401-the-worlds-first-commercial-hydrogen-plane https://www.bbc.com/future/article/20210401-the-worlds-first... https://www.aircargoweek.com/zeroavia-and-monte-strike-deal-for-100-hydrogen-electric-powertrains/ https://www.aircargoweek.com/zeroavia-and-monte-strike-deal-... https://www.flyingmag.com/joby-secretly-bought-a-hydrogen-electric-aircraft-developer/ https://www.flyingmag.com/joby-secretly-bought-a-hydrogen-el... https://interestingengineering.com/german-firm-record-altitude-7230-feet https://interestingengineering.com/german-firm-record-altitu...
mike_hock 4y ago
I mean, why should regulations me more lenient on sci-fi chopper/plane crossovers than on regular choppers?
andrepd 4y ago
https://www.youtube.com/watch?v=aH4b3sAs-l8 https://www.youtube.com/watch?v=aH4b3sAs-l8
- lucb1e 4y ago
  Wendover "Why Electric Planes are Inevitably Coming" to save others a click... please don't post only a random UUID as an answer. I also find linking videos as a reply to something a bit weird, like how many minutes is one supposed to invest in understanding your point? Are you even making a point / answering a specific question, or is it just an interesting video on the topic? Articles are much easier to quote from or skim, depending on what you mean to say.
tppiotrowski 4y ago
I think there's a segment for flight instruction. I think flight lessons are usually short in duration.
leviathon 4y ago
I assume that in a glide the wings are functional. The issue with all of these coaxial, non-contra rotating VTOL aircraft is that they don't allow autorotation, which usually allows helicopters to land using the deceleration generated by natural blade rotation in descent. This is a regulation and many of these VTOL aircraft will never make it to production unless they solve this problem.

toomuchtodo 4y ago

Enjoy the engineering achievement in the moment.

kurthr 4y ago

A lot of the electric (mostly fuel cell) aviation startup industry is funded/supported by currently profitable aviation companies. The 1000hp motors for them are, like the airframes, one of the mostly off-the-shelf elements of their development. I agree that even modern batteries are pretty absurd for any human scale flight, though scaling laws make smaller aircraft more reasonable.

amelius 4y ago
Isn't synthetic fuel much more promising?
- jeffbee 4y ago
  Yeah they are, and this fact is just overlooked by people who aren't thinking through the implications of abundant renewable energy. With a surplus of renewable energy it makes much more sense to manufacture synthetic liquid fuels and burn them, than it does to power airplanes with batteries. The energy cycle is grossly inefficient but nobody is going to care because the energy inputs will be nearly cost-free.
  - frosted-flakes 4y ago
    I had that thought recently. Renewable energy sources like wind need a lot of energy storage. That is, unless you over-provision them so much that they can always meet demand even at peak times. This leaves you with over-production at other times, which could be used for other purposes that don't need to run continuously: synthetic jet fuel production, water desalination, etc. Basically, overprovision and then set electricity rates based on demand, and the renewable energy "storage problem" might just sort itself out. Of course, all those windmills and solar panels will cost an awful lot, so it might not be as simple as "overprovisioning".
    - Sebb767 4y ago
      > That is, unless you over-provision them so much that they can always meet demand even at peak times. Overprovisioning solar to power the grid on ice cold, windless new moon night is going to be hard. Having somewhere to put excess energy and some overprovisioning is always good, but it won't solve all storage problems.
      - aftbit 4y ago
        If we can build a superconducting grid, we can transport power from the parts of the planet where it is sunny or windy to the parts where it isn't. Assuming that everyone remains friendly and operational, that is.
  - zbrozek 4y ago
    CAISO hits about 100gCO2e/KWh during the day. And I run a solar surplus that I don't put back on the grid. I'd be really happy if there were a good way for me to turn excess electricity into something I could use later. Maybe that's hydrogen. Maybe that's capturing carbon and putting it into liquid fuels. Maybe that's creating graphite that I can use for fun personal projects. But regardless, I don't expect grid electricity prices to fall. Probably not in the US. Definitely not in CA.
- robonerd 4y ago
  From a CO2 perspective, synthetic fuels don't have an intrinsic advantage, unless you use biomass as your source of carbon. Traditionally, synthetic fuel has been made using coal or natural gas as the source of carbon. There is still some advantage to this, the nitrogen and sulfur content of the fuel can be dramatically reduced, which is great. But with regard to C02 specifically, you're basically burning coal. With biofuels, I think care needs to be taken to ensure we don't ruin the price of food for people by incentivizing farmers to grow fuel feedstock instead. Biofuels made from algae might be the best, since this wouldn't require the use of arable farmland. Another approach is to pull the CO2 straight out of sea water. Apparently the US Navy thinks this might be a viable approach, since their nuclear aircraft carriers have power to spare.
  - sky-kedge0749 4y ago
    I recently commented about synthetic jet fuel in another thread https://news.ycombinator.com/item?id=31704829 https://news.ycombinator.com/item?id=31704829: > A problem with biofuel is scaling it up, see: https://ieeexplore.ieee.org/document/7498153 https://ieeexplore.ieee.org/document/7498153. According to that article the U.S. would need to devote "an area bigger than Texas and California and Pennsylvania combined" to crops specifically for its own jet biofuel needs. That's just for flying, not for food or fuel for ground transportation or anything else. Also that article says that from 2009-2013 a $100 million effort was made to figure out how to get sufficient synthetic fuel from algae but they eventually gave up and went back to the drawing board.
    - ncmncm 4y ago
      Biofuel is an obvious dead end. The future has no place for biofuel in any substantial amount.
      - trashtester 4y ago
        Ethanol made from food (like corn) is a dead end. Firewood and derivatives have always had an important place in heating and cooking, and are likely to continue in that role for a while. Other types of biomass based hard fuels (from recycled garbage/waste, algae, etc) will most likely also play a role in electricity production and heating, but perhaps a small one (unless algae based biomass takes off). And for liquid fuels for transportation use, algae may also end up being a competitor to hydrogen when oil runs out. I remember there were a lot of companies working in that space 10 years ago, but then there was the oil price crash in 2015, and it seems many switched away. For instance algenol was positioning itself as a fuel company, but appear to have diversified: https://www.algenol.com/sustainable-products/?category=ndustrials https://www.algenol.com/sustainable-products/?category=ndust... If oil prices remain at current levels, though, algae may be only a few years away from scaling up to take a significant part of the market.
- hannob 4y ago
  There's been an EU funded research project that did some projections on the electricity needed for e-fuels. See the graphic on page 44: https://www.fch.europa.eu/sites/default/files/FCH%20Docs/20200507_Hydrogen%20Powered%20Aviation%20report_FINAL%20web%20%28ID%208706035%29.pdf https://www.fch.europa.eu/sites/default/files/FCH%20Docs/202... For pure e-fuels they project 32 PWh. That is, to put it in perspective, more than the total world electricity production today. You'll want to use every technology available to do this in a more efficient way - batteries for very short ranges, hydrogen for mid ranges, e-fuels only for long range where nothing else works. It'll still be very challenging and likely the current growth projections of the aviation industry will be seen as unrealistic fantasies at some point in the future.
  - lukeschlather 4y ago
    > For pure e-fuels they project 32 PWh. That is, to put it in perspective, more than the total world electricity production today. Total annual electricity production is 161 PWh. THe PDF you linked puts it in perspective by saying that if it were purely powered by renewable energy it would increase the size of the renewable energy sector by 3 to 5 times. In other words this doesn't sound hard at all from an electricity standpoint. If electrical generation were half the cost it would be economical right now.
    - moby_click 4y ago
      From https://pubs.rsc.org/en/content/articlelanding/2020/se/c9se00479c https://pubs.rsc.org/en/content/articlelanding/2020/se/c9se0... > We find that an electricity emissions factor of less than 139 g CO2e per kW h is required for this [Direct Air Capture system paired with Fischer–Tropsch synthesis] pathway to provide a climate benefit over conventional diesel fuel. The grid averages in most regions are higher than that. I don't think multiplying current renewable generation just for jet fuel is easy.
- bbojan 4y ago
  Burning any fuel in our atmosphere produces nitrous oxides. Synthetic/carbon neutral fuels won't help with that.
  - SoftTalker 4y ago
    These can possibly be addressed by catalytic converters in the exhaust (not sure how feasible that is in a turbine engine though). In any event, it's a small fraction of total greenhouse emissions, dwarfed by CO2. Let's not let perfect be the enemy of good.
    - bbojan 4y ago
      Oh I wasn't concerned about their greenhouse effect contribution. NOx can cause asthma and bronchitis and can aggravate pre-existing heart conditions. They also form smog. Did I mention that they are bad for the ozone layer?

ramesh31 4y ago

>This doesn't really mesh into the existing aviation industry, so proponents of these small electric planes usually propose creating new markets entirely; e.g. Uber for Helicopters. But I'm pretty skeptical that laws will allow regular operation of these in residential neighborhoods for long, if at all. I can see it becoming more of "Greyhound for Helicopters". Practically every town in the US greater than a few thousand population has at least a local municipal airport. With electrification, aviation can become so cheap that all of these fields will just have a few commuter size electric aircraft that feed into to the rest of our existing airport infrastructure. And with the planes being so small, there's really no need for TSA security or anything, it becomes as simple as buying a ticket on your phone and hopping on the plane like a bus.

908B64B197 4y ago
> And with the planes being so small, there's really no need for TSA security or anything There's no need for larger planes either for zero-risk travelers.
- deleted 4y ago
  [deleted]
akira2501 4y ago
Granted, this is a new type of transport.. but the current metrics on air flight safety do not support this idea. Take offs and landings are the most dangerous part of flight, and still account for planes being more dangerous _per trip_ than most other modes of transport. Planning to create a plane that fills this space is planning to create a plane that suffers a lot of accidents for almost no real gain over current options. Buses are incredibly safe. If you want better busses, build those instead. This obsession with floating to your destination above the ground does not seem wise or worthwhile.
- ghaff 4y ago
  It's trivial to create a luxury "bus" in just about any form factor you want to from a full-size motor coach down to a limo. Presumably the economics don't work in most cases. Of course, if you're talking small municipal airports in the US, the vast majority of people living there, especially those who can afford somewhat upscale transportation, probably own a car.

rklaehn 4y ago

The energy density of gasoline does not matter at all. Batteries are good enough for some applications, like short distance flights. And the operating costs for use cases where batteries work strongly favour batteries. Power density has not been a problem for a while. We are not anywhere near the theoretical limits of battery energy density. So as soon as there are some commercial applications for battery powered flight, there will be a strong economic incentive to get closer to the theoretical limits. Current jet engines are absolute engineering miracles that go very close to the physical limits to get maximum efficiency. But it took several decades to get there.

whatshisface 4y ago
There is already a lot of economic incentive for lighter batteries.
- rklaehn 4y ago
  Yes, and they are improving by a few percent every year. No major breakthroughs, but compounding improvements year over year, which do add up. Batteries have improved incredibly in my lifetime. As a kid I had an electric RC plane that barely made it off the ground. Now you can get pretty cheap aerobatic RC planes that easily compete with gasoline powered models. Battery powered screwdrivers used to be incredibly underpowered. Now I have a very decent battery powered rotary hammer... https://cdn.arstechnica.net/wp-content/uploads/2021/05/bnef_e_density-1440x810.jpg https://cdn.arstechnica.net/wp-content/uploads/2021/05/bnef_...
robonerd 4y ago
> The energy density of gasoline does not matter at all. Well if we're talking about commercial aviation, we're talking about jet fuel not gasoline. Regardless, it obviously matters a lot. A fully loaded 747 freighter has somewhere around 200 tons of jet fuel and a max payload of about 130 tons. They already need more fuel than cargo, and that's with the excellent energy density of jet fuel. Furthermore, traditional planes get lighter the longer they fly as they burn off their substantial fuel loads. The last 20% of the fuel goes a lot further than the first 20%. Batteries don't get this advantage at all. (Dropping batteries from the plane with parachutes is a terrible idea, but I've lost count of the number of times I've seen it proposed..) > We are not anywhere near the theoretical limits of battery energy density. This doesn't jive with what I've read. It's my understanding that we're already near the limits of what electrochemistry can give us, and future advancements are likely to come from improved electrode designs, with maybe 2-3x better performance possible if we're lucky.

nradov 4y ago

Powered lift aircraft are not controllable in a glide, nor are they capable of autorotation like a helicopter. Any complete loss of power will result in an unrecoverable spin. For safety these aircraft rely on redundant systems, plus a parachute. Finding landing sites is going to be a major challenge even if they can solve the battery problems. New York City could be a prime market but there are only a few heliports. Politics and safety issues make it difficult to construct more.

bluejekyll 4y ago
Any idea what the minimum height for the parachute to be effective as a life saving device?
- jeffbee 4y ago
  The Cirrus SR22 needs ~1000ft above ground to effectively deploy the airframe parachute in a spin.
- nradov 4y ago
  Minimum effective altitude for parachutes on light aircraft is about 400 ft agl, but the exact number varies depending on the flight regime. For powered lift aircraft there is likely a small "dead zone" in the flight envelope: too high to survive a crash, too low for the parachute to be effective. This may or may not be acceptable depending on mission risk tolerance and the reliability of other systems. https://www.aopa.org/news-and-media/all-news/2018/march/flight-training-magazine/how-it-works-airframe-parachute https://www.aopa.org/news-and-media/all-news/2018/march/flig...
  - GordonS 4y ago
    > too high to survive a crash, too low for the parachute to be effective This is probably a silly question, but couldn't the pilot just wait until the plane dropped below the dead zone before deploying the parachute?
    - 4y ago

Simon_O_Rourke 4y ago

I'm guessing that if it loses power during flight then it's curtains for the airframe and anyone unlucky enough to be in it. There's lots more work to do to push it out to the mass market, but I could definitely see a niche for it.

themitigating 4y ago
That's the same if a jet engine losses power
- p_l 4y ago
  Nope. Look at the tiny wings, and at what speed it still depended on vertical thrust. It's going to have horrible glide ratio, which means unpowered landings might be, well, not a thing, which leaves you only with emergency full-plane parachute as an option. Pretty much all jet engine planes can do unpowered landings in glide, though admittedly some have pretty high speeds involved - but then they operate by default only on airports that have facilities for such speeds.
  - oliveshell 4y ago
    See this famous example, where a jet airliner ran out of fuel in flight and glided to a successful landing: https://en.wikipedia.org/wiki/Gimli_Glider https://en.wikipedia.org/wiki/Gimli_Glider
    - kayodelycaon 4y ago
      Also Air Transat Flight 236. https://en.m.wikipedia.org/wiki/Air_Transat_Flight_236 https://en.m.wikipedia.org/wiki/Air_Transat_Flight_236
- sokoloff 4y ago
  If a [civilian] jet aircraft loses an engine, it's still a strong favorite to end that flight upright, intact, and on a runway. There are a couple dozen jet engine failures per year; the overwhelming majority end up in a safe conclusion. https://www.cbsnews.com/news/jet-engine-failures-rare-usually-not-fatal/ https://www.cbsnews.com/news/jet-engine-failures-rare-usuall...

dkasper 4y ago

Zero chance of helicopters in cities after 9/11. You can’t fly helicopters over SF or Manhattan anymore except for medical purposes.

JumpCrisscross 4y ago
> can’t fly helicopters over SF or Manhattan Both cities have plenty of potential even with overland banned. New York has a thriving helicopter business between boroughs, up and down both sides of Long Island and to and from the airports. The Bay Area isn’t similarly knitted together, but there is no good argument for not having an electric hop from e.g. Mountain View to SFO.
- CoastalCoder 4y ago
  Can someone comment on why the parent would be (as of this writing) downvoted? I'm wondering if there's some context I'm missing.
  - hef19898 4y ago
    Best guess? Because the helicopter restrictions have nothing to do with 9/11.
- woodruffw 4y ago
  Worth noting that the "thriving" helicopter business is uniformly disliked by residents, due to noise pollution[1]. [1]: https://www.nydailynews.com/news/politics/new-york-elections-government/ny-nyc-lawmakers-target-manhattan-helicopter-noise-complaints-20220515-uddcc42wsjctlmvoxg5cqr2ipe-story.html https://www.nydailynews.com/news/politics/new-york-elections...
mlyle 4y ago
Helicopters aren't banned over Manhattan, etc, despite repeated efforts to do so. In the late 1970's, all the building-top helipads stopped operation after repeated accidents. Still, there's the helipads along the river and a VFR corridor in and out of Manhattan. In 2009, the altitude rules for the corridor got a lot stricter because of repeated fatal accidents.

marcosdumay 4y ago

The low energy density of batteries favors large planes and short distances. The only reason you are seeing them in small planes is that electric propulsion makes VTOL viable, and VTOL favors small planes. There is just this niche in aviation that can't be filled at all by fossil fuel engines, so it's the first to adopt electric ones. And yes, regulations will be the most important factor for those. I imagine it all depends on how silent those planes can be. But I doubt safety will be the limiting factor.

closedloop129 4y ago
In that niche, why are batteries needed? Couldn't those planes be constructed with gas turbines that generate the necessary electricity?
- t0mas88 4y ago
  VTOL works fine with turbines, nearly all large helicopters use turbine engines. They don't use the turbines as generators but instead connect both engines to the rotor via a gearbox.
- marcosdumay 4y ago
  It's a matter of the weight/power relation. While batteries suck on weight/energy, their weight/power is great. The lower that relation, the smaller you can make your VTOL vehicles, and the smaller the vehicles, the cheapest and more economical they are on total.
dr_dshiv 4y ago
> I imagine it all depends on how silent those planes can be. I agree. I’d say, though, not just how silent, but how pleasant sounding. Aesthetics of sound could make or break this industry.
- inb4_cancelled 4y ago
  You either get a chop-chop-chop, or a bzzzt, both incredibly loud. It's not the engine that makes the noise, it's mostly the propeller/rotor. The only advantage of electric VTOLs is easier manufacturing and better control.

scythe 4y ago

>[The electric airplane] doesn't really mesh into the existing aviation industry The reason small electric planes haven't taken off [1] is that they simply haven't proven their cost advantage. About one-sixth of the cost of a flight is fuel, which can be difficult to tax because of jurisdiction shopping. A third is labor, including taking care of the plane. Seven percent goes to building the plane. From: https://www.travelandleisure.com/airlines-airports/airfare-dollars-breakdown https://www.travelandleisure.com/airlines-airports/airfare-d... Optimistically, electric planes could be cheaper to fuel, build and maintain. That's enough to upset an entrenched industry. But it's not clear how it should be organized, and the infrastructure mostly doesn't exist. Plus, the scale you expect to operate at depends on battery technology, which has been a little up in the air [2], and you don't want to design your operations around 1000-mile ranges if it's going to be 2000 in ten years. 1: Sorry. 2: Sorry. But see: https://www.nature.com/articles/s42004-022-00626-2 https://www.nature.com/articles/s42004-022-00626-2

ur-whale 4y ago
There's other aspect than the pure economic aspect: Noise VTOL When both are combined, this makes Urban flight closer to feasable.

cesarb 4y ago

> The power density of even speculative near-future batteries favors small airplanes and short flights. This doesn't really mesh into the existing aviation industry, How short are these short flights? The hugely popular Ponte Aérea (https://en.wikipedia.org/wiki/Ponte_A%C3%A9rea https://en.wikipedia.org/wiki/Ponte_A%C3%A9rea) has a flight duration of one hour.

robonerd 4y ago
That flight is about 230 miles (365 km) as the crow flies, and they're doing it with 737s that seat 100+ each and fly dozens of these flights a day. Compare that to this battery plane that can fly 200 miles: https://cleantechnica.com/2020/01/29/rolls-royce-claims-its-latest-electric-airplane-battery-has-the-highest-energy-density/ https://cleantechnica.com/2020/01/29/rolls-royce-claims-its-... These aren't in the same ballpark; they aren't even playing the same game. If you want something to replace that plane route, I suggest buying a lot of buses.

DennisP 4y ago

It used to mesh a lot better, when general aviation was much bigger than it is now and we had lots of tiny airports. Maybe we could get back to that. VTOL makes it a bit easier.

nradov 4y ago
If you have even a tiny airport with a real runway then you can operate fixed-wing aircraft (possibly electric powered) without the extra cost and risk inherent to VTOL. Lillium and their competitors in the e-VTOL space are trying to create a new market for urban air mobility by bypassing airports and building new heliports, but even if they can solve the technical and legal challenges it's unclear if the economics will work.

kkfx 4y ago

This might give you some insights... https://www.easa.europa.eu/sites/default/files/dfu/uam-full-report.pdf https://www.easa.europa.eu/sites/default/files/dfu/uam-full-... ...of the idea. Witch is essentially, advertisement aside, "the wealthy who happen to live nearby cities, witch happen to be open-sky prisons^w^w factories stuffed with services to achieve the Chinese lockdown with workers who live in the factory, to work, of course ehrm, to achieve the best work life balance (better not say the best to who) can came and go from such erh smart cities in full comfort with means that made things closer, like if they live inside the city and goes with cars. ...In the LONG term, that means we can benefit from the economy of scale living "near" but far less dense than today so at that point in time we have finally found a way to live sufficiently flexible to withstand the technological, social and climate change still being near enough to be social and have economy of scale phenomenon. Or: in the short term we need a good solution for those who can pay, in the medium terms slaves ahem citizens have built a new society and new generations will finally benefit from such progress... In theoretical terms: maintaining roads network is expensive, far expensive if we also need to build new ones, like a potential future arctic "anthropization" due to climate change, so better made few railroads and waterways for heavy loads transports and live humans in the air, far more flexible and cheap. At a certain point in time if we are still alive as a species we will reach that point. Then the "self-sufficiency push" will be the key to reach that goal in an unspecified future. Ps if they loose power there is AFAIK only an emergency parachute for the entire plane. Only it demand, I suppose, a certain altitude to being able to be deployed...

newaccount2021 4y ago

momenti 4y ago

Lilium's plane has 30 engines, multiple independent battery packs, and electric motors are way more reliable than jet engines (due to being so much simpler). A Lilium plane may have a 1000x higher chance of a crash in case of full engine failure, but perhaps that can be compensated for by 1000x times simpler/redundant propulsion technology. This seems to be very hard to assess in theory, so we probably just have to wait and see how it performs in practice.

leoedin 4y ago
That's all very well, as long as there's no common modes of failure. Redundancy can be a means to achieve reliability, but not always. Imagine the cause of failure is a bug which kicks in at a specific time of day, or an integer overflow which happens after a certain amount of uptime, or all the motor drivers are susceptible to a specific RF frequency. It doesn't matter how many motors you have if they're all susceptible to the same failure mode.
- hef19898 4y ago
  That's what certification is there for, isn't it?
- mbreese 4y ago
  > integer overflow which happens after a certain amount of uptime It’s not just electric powered planes that have to worry about such things… this was an issue for the Boeing 777 Dreamliner too. If it was powered on for longer than 248 days, it could lose all electrical power due to an overflow in the generator. https://www.engadget.com/2015-05-01-boeing-787-dreamliner-software-bug.html https://www.engadget.com/2015-05-01-boeing-787-dreamliner-so... I’m not saying it isn’t a concern, but rather it is a concern for all planes (and vehicles for that matter). Many commercial passenger planes are now fly by wire. If you lose electrical power, you’ll also lose control. So, while we’re talking about purely electric planes, the problems are universal.
  - coreyisthename 4y ago
    But many planes can glide to a certain degree. This thing would just fall or glide with zero pilot control. No control surfaces.

ben_w 4y ago

I can’t possibly comment on any specific design, but what I’d like is something that can replace road ambulances. This is partly because I live right next to a busy crossroads and often get multiple simultaneous sirens; but I do also wonder how faster they can arrive by going as the crow flies rather than following street layouts, and how much they have to slow down both for traffic and for blind corners.

jlmorton 4y ago
This is one of the primary reasons I've bought into the eVTOL revolution. I'm also skeptical about these filling city skies, due to safety, noise pollution, etc. But the market for emergency and special purpose vehicles alone is enormous. The US market size for existing _air_ ambulances is itself $4.5 billion dollars annually. The market size for standard ambulances is nearly 10x that. When you expand this to the rest of the world, you can easily see a 100+ billion market for these sorts of vehicles, whether in ambulance services, firefighting, agricultural, or any number of other activities. It's still possible we develop near-to-city eVTOL airport systems for short distance travel. But even absent that, I still think there's a big market opportunity.
SoftTalker 4y ago
For critical patients helicopters are already used. For patients who need to get to a hospital but are short-term in stable condition, is the extra expense of an air ambulance justified, in a health care system that is already unaffordable?
- wolverine876 4y ago
  > For critical patients helicopters are already used. I'm sure they are used based on a cost/benefit calculation - not everyone gets them. If eVTOL reduces the cost, many more can benefit, or those funds can be shifted to something else.
- ben_w 4y ago
  The ability to replace road ambulances is, I think, inherently a cost claim. After all, capability is already solved with, as you say, helicopters.

dzhiurgis 4y ago

Dropbox vs rsync moment right here

theptip 4y ago

This was posted on HN a while ago; of course the numbers are aspirational but this explains their business model: https://lilium.com/newsroom-detail/why-regional-air-mobility https://lilium.com/newsroom-detail/why-regional-air-mobility > If we imagine for a moment that you work in an office in Palo Alto, you could now choose to live in Hayward (5 min flight, $25), downtown San Francisco (10 min flight, $50), or even San Rafael (15 min flight, $70). > Or maybe you want to escape to Lake Tahoe for a long weekend? That would be less than an hour on a Lilium Jet, at a cost of around $250 at launch and less in the near future. It might not be something you’d do every weekend, but saving you three hours each way might well make it worthwhile for an occasional trip. Obviously at first this will be a luxury good, but it's not obvious that it'll remain out of reach for the middle class. (Sure, it'll never be cheaper than a bus.) It's a fair question exactly how much regulatory change this approach requires, but my impression is that they are trying to operate within existing constraints (I'd appreciate any insight from experts in the aviation space though).

bufferoverflow 4y ago
You would have to be making a lot of money to justify 2 such flights per day. 25 * 2 * 22 = $1100/mo = $13.2K / year.
- mbreese 4y ago
  But if you can live in a cheaper place than Palo Alto, you’ll make back that $15K per year in lower house payments. And if you only have a comfortable commute of 15-20 min each way as opposed to an hour (or more), your standard of living will be much nicer too.
  - duhast 4y ago
    House prices will adjust once air taxis take off (no pun intended).
  - theYipster 4y ago
    Perhaps not. A recent study (can't remember where, but industry specific) proposed that EVTOL economics--at scale--will settle at a CASM of $3. (CASM = cost per available seat mile. Note RASM, or revenue per available seat mile, will be higher or these businesses won't make a profit.) With a CASM of $3, this study showed that only 0.03% of the Bay Area will be wealthy enough to commute on these vehicles on anything resembling a regular basis.

bozhark 4y ago

Air taxi is their market

clouddrover 4y ago

> The power density of even speculative near-future batteries favors small airplanes and short flights. Use a hydrogen fuel cell instead: https://www.bbc.com/future/article/20210401-the-worlds-first-commercial-hydrogen-plane https://www.bbc.com/future/article/20210401-the-worlds-first... https://www.aircargoweek.com/zeroavia-and-monte-strike-deal-for-100-hydrogen-electric-powertrains/ https://www.aircargoweek.com/zeroavia-and-monte-strike-deal-... https://www.flyingmag.com/joby-secretly-bought-a-hydrogen-electric-aircraft-developer/ https://www.flyingmag.com/joby-secretly-bought-a-hydrogen-el... https://interestingengineering.com/german-firm-record-altitude-7230-feet https://interestingengineering.com/german-firm-record-altitu...

mike_hock 4y ago

I mean, why should regulations me more lenient on sci-fi chopper/plane crossovers than on regular choppers?

andrepd 4y ago

https://www.youtube.com/watch?v=aH4b3sAs-l8 https://www.youtube.com/watch?v=aH4b3sAs-l8

lucb1e 4y ago
Wendover "Why Electric Planes are Inevitably Coming" to save others a click... please don't post only a random UUID as an answer. I also find linking videos as a reply to something a bit weird, like how many minutes is one supposed to invest in understanding your point? Are you even making a point / answering a specific question, or is it just an interesting video on the topic? Articles are much easier to quote from or skim, depending on what you mean to say.

tppiotrowski 4y ago

I think there's a segment for flight instruction. I think flight lessons are usually short in duration.

leviathon 4y ago

I assume that in a glide the wings are functional. The issue with all of these coaxial, non-contra rotating VTOL aircraft is that they don't allow autorotation, which usually allows helicopters to land using the deceleration generated by natural blade rotation in descent. This is a regulation and many of these VTOL aircraft will never make it to production unless they solve this problem.