12 ms·

You can do small aircraft like this, no problem. The trouble is you can't scale it up, due to how quickly the power and energy demands go up. This thing is 560

• Gravityloss 7y ago
  How would planes would look like if fuel prices increased a few fold? I would assume probably less jets and more turbine aircraft, at least on short trips. Straight wings and slower speeds. Boeing and Airbus might lose some market share. Boeing never had a turboprop, Airbus owns 50% of ATR.
  • ericpauley 7y ago
    > less jets and more turbine aircraft Assuming you mean turbofan vs. turboprop here, since both of these are turbine-driven. In either case, my understanding is that turboprops don't present a substantial gain in efficiency, as turbofans allow for higher and faster cruising altitude, which reduces drag on the airframe.
  • Gibbon1 7y ago
    > How would planes would look like if fuel prices increased a few fold? Like High speed rail
    • deleted 7y ago
      [deleted]
• apendleton 7y ago
  That's all undoubtedly true, but fortunately, most flights don't require the capabilities of an A380, and in fact, demand for that specific set of capabilities is apparently low enough to stop building them altogether. Even for A320 flights, most are not 3500 miles, even if the aircraft is capable of it. If we could make progress targeting just short hops targeted by DASH-8s or CRJs or whatever, we could still make significant progress, even if it meant leaving the longer-haul flights alone, or targeting their emissions with different technologies (synthetic fuels from carbon capture, maybe).
  • 0xffff2 7y ago
    All electric with this century's technology might work for 8-16 passenger short-haul aircraft, if that market can be created (think, many flights from various regional airports between the SF Bay Area and LA area). Nothing bigger is going to fly without a massive breakthrough in battery energy density.
    • anongraddebt 7y ago
      I agree. But can you explain why this is? For me, it's just a hunch.
      • 0xffff2 7y ago
        It really just comes down to energy density and the fact that batteries weigh just as much when you land as when you takeoff, whereas you burn off most of your fuel over the course of a jet-powered flight. Those two things together mean that as you increase the size of your aircraft, batteries take up a bigger percentage of your available weight budget. It's pretty much a smooth curve, with the breakeven point depending primarily on energy density of your batteries. Until very recently, the electric aircraft weren't possible at all. We're now at the point where two seat trainers with short (but long enough for a typical lesson) endurance are possible and in production. If you look at where battery tech is going, we can probably push that up to 8ish seats and a somewhat longer endurance within a few decades. When you look at the size of even a small regional jet, it doesn't seem likely that current battery tech is ever going to get us to the energy density necessary to make it work.
• SECProto 7y ago
  Power (kW) determines takeoff weight (ie plane size/passenger count), energy (kWh) determines range. This article doesn't have all the info needed to say how this would scale. For instance, if the energy storage of the batteries doubled but the power stayed the same, you couldn't make the plane capacity any bigger but you could extend the range to more than double.
• deepspace 7y ago
  > This thing is 560 kW and gets a range of 86 nmi Not even that. I believe an 86 nmi range is what they are hoping to achieve by 2025. Current range is a fraction of that. The technology demonstrator has a theoretical flight time of 15 minutes and no ability to carry passengers because all the room/weight is taken up by batteries.
  • walrus01 7y ago
    It seems to me that they have two somewhat separate engineering challenges. The electric motor and throttle control system, all the drive train stuff forward of the instrument panel in a Beaver. Plus however they retrofitted the cockpit engine control. Which might be quite a bit lighter than a pt6 turbine retrofit to turn an old Beaver into a turbo Beaver. And then the other much harder problem which is achieving sufficient Wh per kg energy density in batteries, and Wh per litre of volume. For which they are dependent on global factors for r&d of batteries and improvement in density.
  • beefield 7y ago
    Do you have a source? (Not trying to be snarky but seriously interested. Haven't seen any technical details anywhere...)
  • Robotbeat 7y ago
    30 minute flight time, not 15. Should have approximately 86 mile range with this one. There's plenty of room for passengers in this concept. Where are you getting this false information?
    • deepspace 7y ago
      See: https://www.skiesmag.com/news/harbour-air-makes-history-with-electric-powered-beaver-flight/ https://www.skiesmag.com/news/harbour-air-makes-history-with... From the article: > What certainly hasn’t been done before is to fill a Beaver’s cabin with lithium-ion batteries, taking the plane to its gross weight. As a technology demonstrator, this eBeaver isn’t carrying passengers — there isn’t room — and will only have a 15-minute endurance with a 25-minute reserve.
• chris_va 7y ago
  I could see a non-rechargeable electric battery (but refillable, ala jet fuel) such as aluminum-air maybe working. The round trip efficiency would be similar to diesel (since you are re-smelting rather than recharging), but the effective energy density on the plane could actually be much better than jet fuel.
• darksaints 7y ago
  Fuel cells are a possibility. There is some pretty high power densities (2.5kw/kg for SOFCs, 10kw/kg for less efficient PEMs). Electric motors are now reaching 15kw/kg. For comparison, a GE90 is about 10kw/kg, and older turbofans down to 2kw/kg. Running on liquid hydrogen presents some problems that are definitely solvable, but SOFCs can run on pretty much any hydrocarbon fuels at extremely high efficiencies (50-60%, 80% with combined cycles, compared to the ~45% that jet engines get). I actually think the future may be a lot more simple than we're making it out to be. With some slight modifications to design, we could run existing turbofans on liquid hydrogen fuel. The biggest objection that most people have is the storage of hydrogen...but liquid hydrogen doesn't actually need to be stored in cryo tanks as long as the fuel is being used at faster rates than it evaporates. That's not a problem with jet engine consumption rates...low tech insulation may be sufficient.
  • avmich 7y ago
    There reportedly is an additional threat to the climate coming from inversion traces (modifies enough of Earth albedo?), so if we're delivering water to high altitudes, it's still not good. Electrical motors would solve this; if we'd be able to avoid dispersing water from fuel cells up high, that could work. LH2 has storage - and safety - issues still not solved. Toyota Mirai approaches it from a different angle, with some other shortcomings.
    • WalterBright 7y ago
      Burning kerosene also delivers water to high altitudes - the result is contrails.
• riazrizvi 7y ago
  According to my numbers an electric 747 would get more people further. 1. DHC-2 takes 6 people 86 miles ~= 500person/miles 2. 747 potential battery payload ~= 200,000kg (fuel capacity) 3. Power capacity of 200,000kg lithium-in ~= 25MW hours 4. Power required to take off, assuming 2.5 minutes to reach cruising altitude ~= 90MW * 2.5 / 60 ~= 4MWh 5. Power to cruise at about 600mph ~= 1/4 power to take off = 22MW (waves hand) 6. Time available to cruise ~= 1hr 7. Distance cruised ~= 600miles 8. Electric 747 takes 600 people 600 miles = 360,000person/miles Maybe the power to cruise is 1/2 of power to take off, they'd still get 120,000person/miles.
  • jacquesm 7y ago
    It takes a 747 quite a bit more than 2.5 minutes to reach cruising altitude. 30,000 ft at 5000 fpm is 6 minutes, and engine input is a lot higher than 90 MW because engines are not even close to 100% efficient (neither are electrical ones). Also, the weight on landing is critical not on takeoff, and you can't exactly shed battery weight because empty batteries weigh roughly the same as full ones do, so you will need to take maximum landing weight into account. Finally, you need to take reserve fuel into account, alternates and headwinds. I think you should re-do these numbers with more realistic inputs.
    • riazrizvi 7y ago
      Reserve fuel? I didn’t even allocate any fuel to land, I am assuming passengers won’t mind the bumps at their destination, you know for the planet.
      • catalogia 7y ago
        There are more practical ways to reduce the population than cratering airplanes into runways. Fuel is a major expense for commercial airlines, they don't burn it just for shits and giggles. Airplanes use fuel when landing because destroyed aircraft and piles of corpses will quickly cost more than any fuel they'd save by trying to glide every plane to the ground.
• gok 7y ago
  Jets consume an unusual amount of energy and you don't run them at full throttle all the time. You'd probably use propellers and/or ducted fans for any electric airliner.
• manigandham 7y ago
  Also batteries weigh the same at landing and takeoff while jets rely on the reduced weight from fuel burn for safe landing.
  • SahAssar 7y ago
    No, not for safe landing. If a jet couldn't land safely while fully tanked then they would not be able to land in emergencies happening early in the flight. They rely on the plane being lighter from fuel burn and therefore more efficient to extend their possible flight time, but not for safety.
    • totallyabstract 7y ago
      It isn't an issue for smaller planes (A320, 737), but larger planes (such as 747, 777, A340, A380) usually have a lower maximum landing weight than their takeoff weight. If an emergency happens early in flight they usually have to dump fuel to reduce weight before they can land. https://en.wikipedia.org/wiki/Fuel_dumping https://en.wikipedia.org/wiki/Fuel_dumping
    • jseutter 7y ago
      I guess it depends on what you call a safe landing. For large airplanes the maximum takeoff weight is typically greater than the maximum landing weight. If an airplane lands overweight it can no longer fly until it has been inspected and repaired. Most emergencies will involve flying around for long enough to get the aircraft within the acceptable weight limit. Some older aircraft have the ability to dump fuel, although I don't know of any new ones that have this capability. Needing to land before getting under weight usually means a crash landing. In modern times, very few things like fire or an engine self-destructing will require immediately getting out of the air. It is usually better to fly in a straight line, figure out what is going on, figure out where to land, then land. This lets you get underweight, lets you communicate with air traffic control, lets emergency services prepare, etc.
    • manigandham 7y ago
      An emergency overweight/crash landing is the opposite of a safe landing. Airliners will dump fuel or keep flying to get below maximum landing weight if possible. If they're still overweight and manage to land without issue, the plane will need to be inspected and repaired before it can fly again.
• Robotbeat 7y ago
  This is not true. It's easier to scale up. You get more efficient. Scaling up an electric motor is not particularly hard. Some of the largest machines in existence are electric. Power is not a challenge for electric. In fact, this electrified seaplane has much more power (560kW) than the original radial piston engine one (336kW), and even more than the turboprop conversion (510kW). A LOT of very confident people on the Internet post lots of very wrong and/or outdated misinformation about electric aircraft (and electric vehicles in general). Energy is a challenge, but the answer there is to increase efficiency and increase the mass of the vehicle which is battery. Both of those together give you a usable range of about 1000km. The same motor provider, Magnix, is also providing the motors for the 1000km range Eviation Alice. Just because a conventional aircraft maker thinks something isn't possible, doesn't mean someone can't make it work. It most certainly doesn't require 30 times the energy density. For the same exact reason why electric cars don't require batteries with 30 times the energy density to compete with gasoline cars.
  • ben_w 7y ago
    All depends on what you want. You can have “infinite” range with “no” battery — gliders are a thing, you can rise on thermals and turn the potential energy into kinetic to get wherever. But if you want to go as fast as a chemical engine and sustain that for as long as a chemical engine, you either need at least the energy density of a chemical fuel or some way to refuel in-flight. Fuel efficient often means “slow”. Great for cargo, not so much for passengers. Edit: Just to add, I’m looking forward to a future of short-range electric personal aircraft, I’m just not expecting pure electric intercontinental for anyone other than hobbyists — unless there’s a big breakthrough in density or wireless power transmission.
    • Robotbeat 7y ago
      The longest range conventional chemical aircraft flew around the world without landing. It's not necessary to equal that range for any commercial application. Kerosene is better than it needs to be. Fuel efficient for aircraft doesn't necessarily mean slow, however (unlike ships). What matters is cruise lift to drag ratio. As long as you can adjust cruise altitude for peak efficiency and as long as all the flow is fully subsonic, then lift to drag ratio is mostly independent of speed (as you can increase altitude where the air is thinner to compensate). So yeah, electric aircraft might stay at Mach 0.5 or so, but they don't need to be slow. Mach 0.5 is still much faster than any passenger high speed rail service and MUCH faster than car or bus or boat. Pure electric intercontinental may be feasible for near-term chemistries like lithium-sulfur if you continue to push efficiencies (both structural and aerodynamic). Very long haul, like LA to Tokyo, will need lithium-air technology which is a few decades off.
• eloff 7y ago
  We can accomplish the same by producing the jet fuel using electricity. Realistically this will likely involve methane (natural gas) extracted from the ground and water, but it could one day be carbon neutral using captured carbon. The trick is to use clean energy like nuclear of renewables. There was an article on HN just recently about doing that with portable nuclear generators like those used on ships, this could be done right in the airport. We already have a fantastic dense energy battery called kerosene. All we need to do is make it carbon neutral and our existing aviation tech won't even need to change.
  • mrpopo 7y ago
    > All we need to do is make it carbon neutral and our existing aviation tech won't even need to change. Except making it carbon neutral will require enormous amounts of energy, shift the price up, and make aviation available only to the richest among us. Aviation industry may keep existing, but will need to scale down.
    • nine_k 7y ago
      If the fuel is synthetic anyway, uh can be made better than kerosene. Also, we have a huge amount of free nuclear energy, daily delivered from Sun, about 1 kW / m². It is nit stable enough for electric baseload, but, depending on the process, may be adequate for fuel synthesis. North of Sahara may become a primary source of jet fuel, given its vast amounts of insolation, cheapness of the land, and access to seawater. Not exactly tomorrow, though.
      • nradov 7y ago
        Better than kerosene how? You're not going to get higher energy density without increasing safety risks.
      • mrpopo 7y ago
        Not exactly tomorrow, but we're facing a problem today. What are we supposed to do to reduce CO2 emissions between today and the mythical day we will have unlimited amounts of synthetic fuel available shipped by tankers from Morocco?
• notatoad 7y ago
  the scaling problem might be real, but it's not really a problem for harbour air, whose primary routes are ~50km from vancouver to victoria or ~80km from vancouver to whistler on nothing bigger than a twin otter.
  • 0xffff2 7y ago
    The scaling problem is real. There's no electric plane in the world that can do that route with passengers right now (including this one). The scaling problem is probably surmountable for this particular use case, but it's far from trivial.
• copperx 7y ago
  Is this battery limitation how we get flying cars?
• bamboozled 7y ago
  I’m sure you have your valid reasons for doubting the feasibility of such a plane, yet here we are in 2019 talking over a network which was completely inconceivable at one point in history. I just read your message as, “Can’t be done yet, will most likely be done somehow in the near future”.
• cma 7y ago
  Shouldn't it be easier to scale up at least to a point? Cross section increases slower than interior volume. Scaling up on range is different, but just scaling size/passenger count I would think would be easier.
• jillesvangurp 7y ago
  Big aircraft are a thing because small aircraft are very expensive to operate. In GA there's a thing called the 100$ hamburger which is basically pilots doing short flights to grab a burger and spending about 100$ on fuel to get some air time. These are short hops and the handful of companies operating flights commercially for this kind of distances charge similar amounts (or way more) for the privilege per passenger. The main reason that this market is so small is the fuel cost. If you drastically cut that cost, you create a new market. What electrical flight will do initially is enable the 5$ hamburger flight and create that market. Same distance, same speed, fraction of the cost. GA is currently prohibitively expensive mainly because of fuel. Operating that kind of flights commercially offers similar advantages though you still have to account for the pilots. And while pilot cost is a factor, their availability is a much bigger problem. There simply aren't enough of them to operate the tens of thousands of mass produced electrical planes that on paper could out compete commuter jets on cost, scale, noise, flexibility, ability to land just about anywhere, etc. The solution to that is self flying planes, aka. drones. This will likely happen long before we train up hundreds of thousands of new pilots. Like self driving cars there are challenges for this and like self driving cars those challenges are increasingly of a legal rather than a technical nature. It's technically feasible but getting permission to actually start doing this will take time and is happening very slowly despite e.g. Waymo 'drivers' actually needing to touch their controls is now becoming a once every few tens of thousands of miles kind of thing. The list price for the Eviation Alice (projected to hit the market in 3-5 years) is around 3M and flies 9 passengers. The list price for an A319 is around 90M and flies about up to 160 passengers. So, ballpark it's not unthinkable to fly similar amounts of people using 20-30 mass produced self flying electrical planes competing on most 1-2 hour hops that these jets are typically used for. That will take decades to happen but it is entirely feasible with today's level of technology. Small planes are not fundamentally hard. Cessna nailed mass production decades ago and electrical planes are vastly simpler (way less moving or combustible parts) And as Tesla and other battery manufacturers are showing, there's nothing fundamentally hard about producing a few hundred kwh of battery at a reasonable weight. A small plane with 500-1000khwh of battery will have a very usable range. With increasing energy densities, that will eventually extend into longer ranges as well. The Eviation Alice manages close to 600 miles on 900 kwh of what is essentially similar to the current energy density of mass produced EVs i.e. hardly the state of the art in battery tech. They are holding back here to get this thing certified ASAP instead of opting for already existing newer battery tech. The impressive thing about this particular announcement is that it is a cost effective conversion for planes that are 60+ years old with a very well understood mission, which is very short hops. The reason that is economical is because combustion engine economics for that are so spectacularly bad and always have been. Electric flight is going to kill that market first and very soon because it hardly was a market to begin with. Small electrical planes crossing the Atlantic is going to happen at some point in the next decade or so. From there to that becoming a routine thing will take more time. But once that happens, it's likely to challenge the economics of dong the same in a 747. There's no fundamental need to scale electrical planes to that size even though that will probably eventually actually happen as well; but that will indeed require decades of improvements in energy density in batteries. The only questions around electrical flight is when, not if.
• davedx 7y ago
  > Going from this DHC-2 to the A380 requires an increase in energy storage by a factor of around 14 000x First of all: citation needed. Secondly: it's a disengenious argument to say "you can't scale it up", then give the largest passenger aircraft in operation as your first scale up target. What about scaling up to the size of the propellor aircraft regularly carrying people between Amsterdam and many cities in the United Kingdom every day, or thousands of the other short haul routes? Indonesia is another example.
  • ppf 7y ago
    If we are looking at an energy-conscious (or energy-scarce) future, then we really have to consider what forms of transport are feasible at all. For these kind of short-hop journeys, flight is probably not efficient enough.
• m-i-l 7y ago
  How about using battery powered aeroplanes for shorter trips, and solar powered airships for longer distances? Bear in mind that the first electricity powered flight was an airship: "In 1883 the first electric-powered flight was made by Gaston Tissandier, who fitted a 1.5 hp (1.1 kW) Siemens electric motor to an airship."[0] And we also have solar powered airships which can stay in the air for 6 months at time now[1]. [0] https://en.wikipedia.org/wiki/Airship https://en.wikipedia.org/wiki/Airship [1] https://www.sciencealert.com/this-gigantic-chinese-airship-flies-on-solar-power-for-up-to-six-months-at-a-time https://www.sciencealert.com/this-gigantic-chinese-airship-f...
• rklaehn 7y ago
  Why would it matter how big the plane is? For a certain battery energy density and battery mass fraction, you should get a certain range, no matter what the size of the plane is. If anything, large planes should be a bit more efficient. I think hybrid would be a great compromise. Short range jets spend a lot of kerosene just during taxi and takeoff. If you could just do launch and climb on batteries and then replenish the batteries from a jet powered generator during cruise, that would already be huge in terms of not just CO2 but also ops cost.
• DagAgren 7y ago
  I think people aren't quite willing to face up to the consequence of this, though: This means that commercial air travel, as we know it, is going to go away. We can not afford to keep burning fuel at the rate we do for flights today, and we won't even have that fuel available at some point. And if we can not develop electric or renewable alternatives, which we very well may not, we will just have to stop doing it.