back to article Boeing-backed US upstart reckons it'll be building electric airliners

A naïve American startup run by "dreamers" claims that its electrically powered airliner concept will magically sweep away all of the world's existing problems with air travel. Zunum Aero, based in Washington state, wants to build a fleet of what it calls hybrid electric jets for service on short and medium-haul airline routes …

  1. Mike Moyle Silver badge

    "Ladies and gentlemen, this is your captain speaking. We've run into a bit more headwind than we expected today and we're running a bit low on battery power. At this time, we ask that everyone plug all phones, laptops, and other electronic devices into the power ports on your seats so we can get enough of a boost to get over those mountains ahead of us. Thank you for your cooperation and, as always, thank you for flying ElectricAir."

    1. agurney

      .. and for those of you in enconomy .. could you pedal a little harder please?

    2. The Man Who Fell To Earth Silver badge
      FAIL

      Worthwhile

      These investments suggest that no matter how sketchy Zunum's public information is at present, there must be something worthwhile in it.

      As a long time Silicon Valley veteran with a number of starts under my belt, my experience is that the only VC's more gullible that SV firms are the VC arms of large corporations, which are always considered low tier VC's by anyone in the know. My money is this emperor has no clothes, but no one has the balls to demand a real feasibility analysis be placed in front of them.

  2. Ken Hagan Gold badge

    Just a matter of timing

    Something *like* this is almost inevitable, since toy drones prove that existing batteries have the necessary power-to-weight ratio, better battery technologies are always on the horizon, and an electric plane would presumably be quieter and could be carbon-free.

    Boeing might have reckoned that it was worth their while to buy a seat on the board just-to-see-if and just-in-case these guys are credible. The alternative would be for Boeing to run an in-house project to do the same thing so they might just have decided it was cheaper to share the costs at this early stage.

    1. Trigonoceps occipitalis

      Re: Just a matter of timing

      " ... and an electric plane would presumably be quieter and could be carbon-free."

      So, no carbon fiber then?

      (Yes, I know what you mean, I'm just a perverse bugger sometimes.)

      1. Your alien overlord - fear me

        Re: Just a matter of timing

        I think there are laws against buggering perverses. Whether you do it sometimes or all the time I think you should stop.

    2. GBE

      Re: Just a matter of timing

      "Something *like* this is almost inevitable, since toy drones prove that existing batteries have the necessary power-to-weight ratio"

      Modern batteries do have good power-to-weight ratios. However, the energy-to-weight ratios are still complete shite compared to liquid hydrocarbons. Sure, you could build a battery powered airliner that has enough power to fly _for_a_few_minutes_ before you run out of energy.

      "better battery technologies are always on the horizon,"

      Maybe you've never noticed this, but _the_horizon_never_gets_here_.

      1. jmch Silver badge

        Re: Just a matter of timing

        "Modern batteries do have good power-to-weight ratios. However, the energy-to-weight ratios are still complete shite compared to liquid hydrocarbons. Sure, you could build a battery powered airliner that has enough power to fly _for_a_few_minutes_ before you run out of energy."

        I guess that's where the hybrid concept fits in - maybe its possible to use turbine energy for takeoff and battery power for the rest of the way. If you look at hybrid cars like Prius, for high power and/or long distance they are using petrol, with batteries only for low speed driving or cruising.

        Fuel makes up a huge part of airplane operating costs, so if a hybrid can improve consumption by even 10-20% that's a big win.

        1. Vic

          Re: Just a matter of timing

          Fuel makes up a huge part of airplane operating costs, so if a hybrid can improve consumption by even 10-20% that's a big win.

          Not necessarily. Batteries are always heavy, so the more you carry, the less revenue-earning cargo gets airborne. It's no use trimming your fuel costs by 10% if you carry 30% fewer passengers as a result.

          The numbers I did the other day came out at 4.3TJ in a 787's tanks. Think about the batteries you'd need to save 10% of that - 430GJ. That's a lot of battery; the large Tesla pack holds 85KWh, which equates to 300MJ. So you nominally need 1400 of those to save 10% fuel - in practice, rather less, since a heat engine cannot be 100% efficient. But I doubt you'd get the effect with fewer than 500 packs[1] - and they're 544Kg each. That's 272t of the carrying capacity taken up in batteries; the 787-9 only has 126t to start with...

          Competing with hydrocarbon fuels really is rather difficult.

          Vic.

          [1] That's an efficiency of 35% for the jet engine - that strikes me as reasonable, but I don't have figures to hand to back it up.

          1. bazza Silver badge

            Re: Just a matter of timing

            @Vic,

            The numbers I did the other day came out at 4.3TJ in a 787's tanks. Think about the batteries you'd need to save 10% of that - 430GJ. That's a lot of battery; the large Tesla pack holds 85KWh, which equates to 300MJ. So you nominally need 1400 of those to save 10% fuel - in practice, rather less, since a heat engine cannot be 100% efficient. But I doubt you'd get the effect with fewer than 500 packs[1] - and they're 544Kg each. That's 272t of the carrying capacity taken up in batteries; the 787-9 only has 126t to start with...

            It's worse even than that. Fuel that's burnt gets blown out the back of the engine as H2O, CO2, etc. The aircraft weight decreases during flight, and becomes significantly more efficient as the fuel is burnt. For example, Concorde would drift higher and get faster without increasing the thrust setting as the fuel load burned off.

            Whereas the batteries remain on board. The aircraft efficiency does not improve as the batteries are drained. So their contribution is even less. Worse still is that the aircraft landing weight has gone up, every landing would be at maximum take off weight, and there's very few aircraft out there that can do that now. So the airframe and undercarriage have to be stronger so that it can land whilst still carrying all those tons of batteries. And to avoid putting dents in runways they'd start needing to put extra undercarriage legs on to spread the weight (like a 747), adding even more weight. This makes the aircraft even less efficient. And the brakes would be heavier - so they're going to have a harder time. And the wing would need to be bigger with larger flaps /slats to make the landing performance reliable in all weather conditions, adding yet more weight. And all this extra weight would need more powerful engines to get the whole lot into the air in the first place, so they're going to be heavier. And there's the whole question of how do electricity get turned into hot exhaust. A burning fuel spray is very good at doing that, electric heaters are not. It's a question of surface area. Plus there's no heater element that's going to be light weight (tungsten is heavy) and get as hot as burning fuel. So it'd have to be a motor driving the fan, which is going to be heavier than the equivalent gas generator (lots of copper and iron, not titanium, aluminium, steel and the small amount of nickel used in the turbine blades at the hot end).

            Every pound of 'fuel' remaining at the end of the flight adds a disproportionate number of pounds to the weight of the airframe.

            So if batteries are ever going to compete against kerosene, they have to beat the energy density of kerosene by quite a large margin. It's still not going to work if they just reach parity with hydrocarbons.

            Something like the A380 carries approx 250 tons of fuel, and can land (under max weight conditions) with 70 tons remaining. The equivalent batteries would have to weigh 70 tons, not 250 tons. So the energy density of the battery would have to be 350% that of kerosene.

            It's not that bad because the maximum "fuel" load is then also 70 tons, 180 tons less. So quite a lot of weight could be trimmed (smaller wings, etc). I don't feel like doing the maths model this time of the morning, but it boils down to battery energy density having to be significantly higher than kerosene's before there is any benefit whatsoever.

            Hydrogen would be a better bet I think. If only we could store that in a tank efficiently.

          2. Anonymous Coward
            Anonymous Coward

            Re: Just a matter of timing

            One could dump the batteries as they get depleted...

        2. Tom 64

          Re: Just a matter of timing

          > "Fuel makes up a huge part of airplane operating costs, so if a hybrid can improve consumption by even 10-20% that's a big win."

          Indeed. Taking aviation kerosene out of the equation is also a plus. Refining the stuff is resource intensive.

    3. Eddy Ito Silver badge

      Re: Just a matter of timing

      It fits, they sponsored a thing with University of Cambridge a few years back on an hybrid electric plane. There's also the Sugar Volt hybrid electric study and they've done hydrogen fuel cell drones so they're clearly looking forward to alternative propulsion technologies.

      1. bombastic bob Silver badge
        Devil

        Re: Just a matter of timing

        there was a hybrid nuclear powered bomber once (or being researched, may have never flown). It (would have) used regular jets to take off, and the nuclear engines to keep it in the air. At least we know that a nuke reactor has a VERY high power:weight ratio. So, ya wanna fly on THAT plane? Heh heh heh.

        https://en.wikipedia.org/wiki/Aircraft_Nuclear_Propulsion

        well, maybe when we get fusion reactors going, it would be a nice alternative. but then again it would be best suited for SPACE planes, and we'd still have the terrestrial ones using standard jet fuel.

        Don't forget that MOST electricity for electric cars already comes from fossil-fuel power plants. There's just not enough "Mr. Sun" or wind to do it any other way.

        1. JeffyPoooh Silver badge
          Pint

          Re: Just a matter of timing

          "...a nuke reactor has a VERY high power:weight ratio."

          No. Perhaps VERY high *ENERGY*:weight ratio.

          I'd expect any old turbine would beat any reactor in P:W.

          1. JeffyPoooh Silver badge
            Pint

            Re: Just a matter of timing

            Two DVs without amplification. I suspect muddled thinking on their part. Probably fail to comprehend difference between energy and power.

        2. MachDiamond Silver badge

          Re: Just a matter of timing

          The nuclear powered bomber was a convenient rouse to get the funding for research into Thorium MSR reactors. A couple of iterations of the reactor did very well but the program was cancelled by President Richard Nixon for reasons that some say relate to the fact that LFTR reactors don't produce weapons grade nuclear material to any usable extent.

          There is plenty of Mr Wind and Mr Sun to power electric cars. A study done at Argonne National Laboratories found that it takes 7.43 kWh of electricity to refine one US gallon of gasoline. Most electric cars will go further on 7.43kWh of electricity than a car with good efficiency will on gasoline. There is also the matter of the latent energy in the gasoline itself and the infrastructure cost to move liquid fuels to where they are wanted. From a pollution standpoint, an electric car charged exclusively from coal derived electricity will have a smaller carbon footprint than a gas/diesel powered vehicle due to pollution controls installed on coal power plants. The upside is that in most countries coal plants are being replaced with cleaner natural gas plants (not "clean" but "cleaner"). Solar and wind stations are going up around my area like weeds. Once I've populated my entire south facing roof with solar panels I'll be able to power an electric car for nearly all of my transportation needs. A full "tank" every day and I'll never show up on a date smelling like gasoline.

        3. PNGuinn
          Mushroom

          Re: Just a matter of timing

          "So, ya wanna fly on THAT plane? Heh heh heh."

          Personally I'd rather sit in a confined space in front of / on top of / behind a wacking great nuclear power plant than a B****y great pile of unstable lithium batteries ....

          Come back Hindenberg = all is forgiven.

    4. Anonymous Coward
      Anonymous Coward

      Re: Just a matter of timing

      No on a couple of counts.

      1. Toy drones prove nothing, as these kinds of things don't scale linearly with size.

      2. The dominate noise generation from an aircraft is from the spinning prop/turbine, secondarily from the large mass causing the air to move around it. That does not change.

      1. Yet Another Anonymous coward Silver badge

        Re: Just a matter of timing

        >1. Toy drones prove nothing, as these kinds of things don't scale linearly with size.

        Damn, you mean my paper airliner project might have difficulties?

        I already ordered a ream of "A-99" copier paper

        1. S4qFBxkFFg
          Trollface

          Re: Just a matter of timing

          "I already ordered a ream of "A-99" copier paper"

          The area of an A99 sheet of paper is about one hundredth of a barn.

          Given that 'A' paper sizes are rounded to the nearest mm...

          1. Andy 73

            Re: Just a matter of timing

            You missed the important minus sign there... A(minus)99 is big... very big

            1. S4qFBxkFFg
              FAIL

              Re: Just a matter of timing

              My mistake - that takes it up to about 1% of a square light year...

        2. The First Dave

          Re: Just a matter of timing

          A99 - I didn't realise they actually made paper that small! (Must be thicker than it is wide.)

    5. Anonymous Coward
      Anonymous Coward

      Re: Just a matter of timing

      "Something *like* this is almost inevitable, since toy drones prove that existing batteries have the necessary power-to-weight ratio..."

      This won't work, for the same reason that we don't get giant insects - as you increase all the dimensions the corresponding cross sections are squared but the corresponding volumes, and therefore mass, are cubed.

      For example, a 1 x 1 cube has a face-area of 1 and a volume/mass of 1 whereas a 2 x 2 cube has a face-area of 4 but a volume/mass of 8.

      1. Ken Hagan Gold badge

        Re: Just a matter of timing

        "This won't work, for the same reason that we don't get giant insects - as you increase all the dimensions the corresponding cross sections are squared but the corresponding volumes, and therefore mass, are cubed."

        But the power-to-weight ratio of a battery stays the same, so it rises with the cube of the linear size of the battery.

        Also, the size of insects is limited by the way they breathe, not by their mass. During the Carboniferous period when oxygen levels were much higher (35%), flying insects (and many other forms of life) were much larger.

        Also, also, the effectiveness of wings increases with area. This increase is slower than mass, but you can offset that to some extent by changing the proportions of the plane.

        An electric plane doesn't need to be as good as a kerosine one. It just needs to find a niche where it is more competitive than anything else.

        1. Tannin

          Re: Just a matter of timing

          "An electric plane doesn't need to be as good as a kerosine one. It just needs to find a niche where it is more competitive than anything else."

          Good point. All we need to do now is find a place with hardly any gravity.

  3. Daedalus Silver badge

    Lirpa Loof here...

    Wasn't this supposed to be released to the press last Saturday?

  4. Anonymous Coward
    Facepalm

    Reality check time?

    I sometimes wonder if schools actually still teach physics these days or if that's all turned into "let's learn how to turn on the computer and ask our questions on Google", haven't these guys ever used their brains? Or studied on what they're trying to do?

    Almost every year there's a World Solar challenge held in Australia and the idea is to build a solar powered car which will take the contestants around the continent. Here are some of the highlights of 2015, notice anything peculiar?

    If you look closely you'll notice that most cars are literally packed with solar panels and batteries, often hardly providing any room for the driver. We're talking Australia where the sun is almost literally burning, it's hot there. Yet even here do you come across cars which despite all the batteries, despite the massive solar panels (which are state of the art, when a country participates you can bet that they got some solid government backup) and despite the seering sun cars still manage to fail due to lack of power.

    And these are merely cars which are very aerodynamic (as you can see), and build solely for the race itself. Their only obstacle is (air) friction, and their challenge is power consumption.

    Think about what would happen if they had to bring passengers along....

    Think about what would happen if these had to become trucks to actually transport goods around the continent.

    And then think about the challenge of defying gravity.

    So yeah, time for a reality check I think...

    1. DJO Silver badge

      Re: Reality check time?

      I'm pretty sure they do not plan to power the aircraft by solar power.

      1. Suricou Raven

        Re: Reality check time?

        No, but just as bad - batteries. Batteries have awful energy-to-mass ratios when compared to good old flammable liquids.

        1. DJO Silver badge

          Re: Reality check time?

          Batteries have awful energy-to-mass ratios when compared to good old flammable liquids.

          Also batteries don't lose weight as the energy is consumed so the overall energy requirements will be slightly higher.

          1. Anonymous Coward
            Anonymous Coward

            Re: Reality check time?

            energy requirements will be slightly higher.

            Probably a lot higher.

            You know when you see something and think "sh!t, that's a deal breaker"? I think DJO has just done that for electric aviation. I'd started thinking, "hey, maybe lithium sulphur batteries could get the energy density for air travel", but that doesn't work when you realise that 40% of takeoff weight even with avtur is fuel.

            If you're having to carry forty percent more weight in batteries, and for the entire flight, it simply isn't going to work.

            Simple reality is that "renewable" aviation is going to have to run on synthetic paraffin. And that is going to be VERY expensive.

            1. Richard 12 Silver badge

              Re: Reality check time?

              Might not be paraffin, I would guess probably not.

              There are a variety of biofuels, synthetic fuels and (my favourite) fuels manufactured by genetically-modified bacteria.

              One of those will hopefully scale.

              GM bacteria are particularly nice as appropriate varieties can make petrol, diesel, kerosene or any other desired hydrocarbon directly - though significant technical challenges remain, such as getting the stuff out of the sludge fast enough not to kill the bacteria...

              1. MachDiamond Silver badge

                Re: Reality check time?

                Richard 12, The easiest way to extract the oils from algae based fuels is to just not worry about killing the bacteria. All that needs to be done is to take a sample from the goop before processing and add it to the next batch just like you would do for sourdough bread.

            2. Anonymous Coward
              Anonymous Coward

              Re: Reality check time?

              lithium air, with the gain in efficiency of electric versus fuel motors, could on paper be as good o weight.

              Just no ones made a lithium air battery that's practical

            3. jmch Silver badge

              Re: Reality check time?

              "that doesn't work when you realise that 40% of takeoff weight even with avtur is fuel."

              For Solar Impulse solar-powered electric plane, batteries are approx 25% of weight. So I guess a larger hybrid plane that includes passengers and luggage could take off and cruise with for example 30% of weight that is batteries and 10% fuel for takeoff and emergencies.

              I'm far from having technical aviation knowledge, but from the comments on a Boeing/Airbus article earlier in the week, I believe the biggest energy requirement following takeoff is highly dependent on speed, not so much on weight. So carrying battery weight for the entire flight even when discharged, while being an obstacle might not be a dealbreaker.

              One other thing, again I'm not sure of the fine details but there could be other weight savings from using electric motors vs jet engines, both directly (engine itself weighing less) and indirectly (higher efficiency leading to less fuel requirements)

            4. bombastic bob Silver badge
              WTF?

              Re: Reality check time?

              "Simple reality is that "renewable" aviation is going to have to run on synthetic paraffin. And that is going to be VERY expensive."

              why paraffin? why "renewable?"

              last I heard, fracking will give us up to 100 years of oil supply at current consumption levels. BP had a more conservative estimate back in 2014 of about 53 years...

              so why paraffin? makes no sense.

              if nothing else, use SEWAGE and ORGANIC GARBAGE to make oil. As I understand it, a process for doing so was invented in the 1950's involving high pressure/temperature and a layer of CO gas and maybe some catalysts, and from what I've read, it's an EXOTHERMIC process once you get it going. Yeah, EXOTHERMIC. think about THAT for a moment...

              1. Vic

                Re: Reality check time?

                so why paraffin? makes no sense.

                Because that's what aviation jet engines typically burn...

                Vic.

                1. GBE

                  Re: Reality check time?

                  so why paraffin? makes no sense.

                  Because that's what aviation jet engines typically burn...

                  This may be a US/UK misunderstanding. In the US, the word "paraffin" refers to paraffin wax: the solid stuff you use to make into candles and seal the tops of canning jars:

                  https://en.wikipedia.org/wiki/Paraffin_wax

              2. MachDiamond Silver badge

                Re: Reality check time?

                bombastic bob, I hope your comment about 100 years of oil supply is sarcastic especially when you put the qualifier "at current consumption levels" in the statement. Usage isn't static, it increases all the time. Growth in the world's population is a major factor even if standards of living were held constant. Do a search on YouTube for Al Bartlett. He has passed away but put out an excellent talk on energy and increasing rates of usage. His statement "Modern agriculture is the use of soil to turn petroleum into food" should make people stop and think. With shrinking oil reserves, the price will go up and people will die as food prices shoot up as well.

                Just in the past few days I read an article about how Mexico might be on the downward slope of oil reserves and they are a major supplier to the US market.

            5. Tannin

              Ground-based fuel storage is required

              "Simple reality is that "renewable" aviation is going to have to run on synthetic paraffin. And that is going to be VERY expensive."

              The problem here is that the aircraft has to carry its own energy (e.g., in the form of liquid fuel). If you could figure a way to leave that weight on the ground and only transport the payload itself (together with things required to control and protect that payload, such as seats, structure and control surfaces), you'd be home free.

              Luckily, there is a way. Simply launch aircraft with ground-based electric capapults.

              Naturally, you'd need some serious acceleration in the launch tube - 10g? 100g? lots anyway - but this need not be harmful to passengers or freight provided you have a suitable mechanism to cushion the launch impact, such as a very large rubber band.

          2. hellwig Silver badge

            Re: Reality check time? - batteries don't lose weight

            No, but you could lose the batteries. Just have some sort of power-transferring system drain batteries in a proper order (assuming you don't need the whole pack for voltage/current reasons) and then just eject them from the aircraft.

            Then, you could have a fleet of these super-efficient Australian solar-powered cars I'm hearing about drive around reclaiming the dropped batteries and driving them to the nearest airport. Or even better, leave enough charge in the battery to power the car, just in case it's cloudy.

        2. Yet Another Anonymous coward Silver badge

          Re: Reality check time?

          >Batteries have awful energy-to-mass ratios when compared to good old flammable liquids.

          Only if you want to reuse them.

          If you simply burn them then LiPo has similar energy density to TNT

          1. Sorry that handle is already taken. Silver badge

            Re: Reality check time?

            If you simply burn them then LiPo has similar energy density to TNT

            If that's the case it's still only one third as effective as kerosene!

        3. Number6

          Re: Reality check time?

          Batteries? Why not a really long power cord...

      2. Vic

        Re: Reality check time?

        I'm pretty sure they do not plan to power the aircraft by solar power.

        Solar would actually be the most viable idea here - once above cloud, there really is quite a bit of sun to be had. But you'd still need fuel for below-cloud operations - including all the usual reserves for emergencies, and you'd be force to operate daylight-only. Airlines won't like that...

        Vic.

        1. bombastic bob Silver badge
          Boffin

          Re: Reality check time?

          solar power density is around 1.4kw per square meter. That's less than 2HP per square meter if I did the math properly. I looked that up and found it on a single web site. Perhaps you might corroborate that with other sites. I'm too lazy to do that, heh. And that isn't taking into consideration the "less than 100%" efficiency of a solar panel. Aren't they around 30% these days?

          I think if you did the math, solar energy at ANY altitude [vs the weight of the panels to collect it] would be a net LOSS if you tried to implement it on an aircraft. I cite an earlier post regarding solar cars in Australia...

          1. Vic

            Re: Reality check time?

            I think if you did the math, solar energy at ANY altitude [vs the weight of the panels to collect it] would be a net LOSS if you tried to implement it on an aircraft.

            You'll note that I said it was the "most viable" idea, not that it had any merit :-)

            There have been solar-only aircraft. It can work if the plane is designed for that sort of flight. But getting any passengers aboard is, AFAIK, non-viable, as is getting a choice in where/when you fly...

            Vic.

          2. MachDiamond Silver badge

            Re: Reality check time?

            Solar insolation is about 1kw/sqmeter at the top of the atmosphere and is 700-800w/sqmeter for most of the areas with the largest populations. Solar panels are around 22% efficient at turning that energy into electricity which yields about 170W/sqmeter of solar panel (ish).

            Transportation takes much more energy than solar panels can provide in any form that is useful. The Solar Challenge cars that race across Australia aren't exactly comfortable and nobody would be using them for a school run or weekly shop. I believe that a few have been flipped over on the road from lorries passing on the other side, so they aren't particularly stable either. These are highly engineered vehicles often with the most advanced and expensive solar cell technology. Cells that might not have a very long life span or be so expensive that they would never be able to compete with grid power. It's encouraging to see the technology advance since somebody will find a way to take one of these cell technologies to a commercially viable product or they might point to ways in making current panels a bit more efficient and extend their useful lifetime.

          3. JeffyPoooh Silver badge
            Pint

            Re: Reality check time?

            @bombastic bob

            The DVs are unwarranted. Your post is perfectly logical.

            The eco-airheads have moved into first place, displacing the denialists as the greatest threat to the planet.

            They'd happily spend all the wealth on Earth on stupid ineffective eco-stunts, because apparently there's no priority on actually making efficient progress on such issues.

            Like bringing a $5000 wedding cake to a famine.

            Cheers.

    2. John Brown (no body) Silver badge
      Flame

      Re: Reality check time?

      "Australia where the sun is almost literally burning"

      Just as well it isn't really burning or we'd all be in trouble! Oh, wait....

    3. jmch Silver badge

      Re: Reality check time?

      Solar-powered plane not only already exists, but is already advanced enough to circumnavigate earth, including a single stint across the Atlantic and one China-Hawaii ( https://www.theguardian.com/environment/2016/jul/26/solar-impulse-plane-makes-history-completing-round-the-world-trip ). Solar panel / battery combo is so good that the limit of staying airborne is dependent on pilot stamina, not technical reasons.

      Of course that does not include any passengers, but what these guys are proposing is not a pure battery/solar plane but a hybrid, and targeting much shorter flights (approx 1 hr flight time based on the examples given). So why there are plenty of challenges and it's far from given that this would eventually work (technically AND commercially), it's not that outrageous. Certainly it's a set of technologies that should at least be explored, so good luck to them.

      1. JeffyPoooh Silver badge
        Pint

        Re: Reality check time?

        jmch offered "Solar-powered plane..."

        The only thing that stupid stunt proved was the obvious-in-advance lesson that a solar powered aircraft is completely infeasible. People have jogged around the Earth faster than that stupid stunt. People have sailed around the Earth faster.

        That stupid solar aircraft stunt is the poster child of why airhead eco-stunts have become a greater menace to the planet than even the worst of the empty-headed denialists.

        If you can't understand why these sorts of eco-airhead stunts are part of the problem, then you're part of the problem.

  5. not.known@this.address Bronze badge

    "hybrid" engines?

    Is that like the Hybrid road cars that use the fossil-fuel burning, environment-destroying* infernal combustion engine to keep the piddling little batteries charged?

    I'm not surprised Boing have put money into this - whether it works or not, they have proved what a caring, thoughtful company they are by investigating and investing in "environmentally friendly" technologies (and if it is successful, they won't need to worry about paying for or stealing the tech, they will be part-owners already).

    *Funny how the green lobby consistently neglect to mention the environmental costs of digging up the rare minerals used in the batteries used by "environmentally friendly" cars, the manufacturing, processing and disposal of the batteries and the vehicles themselves (WEEE regulations don't just apply to old fridges...).

    Who knows, maybe they have made a working fuel cell or fusion reactor that can supply the juice to turn the engines...

    Whatever, I wish them luck.

  6. John Smith 19 Gold badge
    Go

    10-50 seat commercial passenger aircraft are a thing.

    And BTW NASA (well the first A) has been looking at way to simplify regional airline operations and make regional airports (of which I believe the US has quite a number) more useful and active (y'know increasing economic around the US, something close to the heart of the D himself).

    Thumbing through an old Popular Mechanics for (IIRC) 1975 I see a blurb about the first flight of an all electric light aircraft (2 seat) with an endurance of 15 mins. Obviously knocked up by a home builder who took the statement "building a human carrying electric aircraft is impossible" as a personal challenge ( the dad of the guy who built that pong game from discrete transistors?)

    4 decades later and behind all the massive hype batteries really have improved quite a bit, as has the generator and power electronics technology (so you can directly connect your generator/alternator to a turbine without a gearbox and then dial in whatever voltage and current you want from the battery pack output).

    The question of course (which being at home with the Kumars failed to answer) is wheather the technology has gotten better enough to built a flying Prius.

    There is a fine line between spotting when all the pieces are available to carry out a truly bold piece of disruptive technology and selling the idea that their might be.

    Time will tell if this is John Carncac's old company or if this is the Oculus Rift of aerospace.

    1. Yet Another Anonymous coward Silver badge

      Re: 10-50 seat commercial passenger aircraft are a thing.

      IIRC there was a proposal by the guy behind the Thrust2 supersonic car to do this in europe.

      A fleet of cheap to run efficent turbo-props using the small grass airfields that surround every major city and industrial area in europe (as a result of an earlier abortive attempt to european integration)

      The idea was that you booked a flight, turned up with no airport screening delay and flew to within a couple of miles of your destination where an uber was waiting for less than a business ticket

      1. Pen-y-gors Silver badge

        Re: 10-50 seat commercial passenger aircraft are a thing.

        turned up with no airport screening delay

        Why would there be no airport screening delay? It's a basic requirement of flight. If you don't spend two hours being strip-searched by the TSA before flying, then you can't fly. Simples. (How on earth did the Wright Brothers even get off the ground without being blown up?)

        1. jmch Silver badge

          Re: 10-50 seat commercial passenger aircraft are a thing.

          I think screening rules differ for smaller and/or private aircraft. Also, any screening would much quicker if (a) there's 20 passengers rather than 200 and (b) there's a few dozen flights per day out of a small airfield rather than a few dozen flights per hour from a major airport

          1. Pen-y-gors Silver badge

            Re: 10-50 seat commercial passenger aircraft are a thing.

            @jmch

            Face it, if the TSA drones are involved, they'll manage to drag screening 20 passengers out for a couple of hours. After all, what else have they got to do all day? If there's no passengers to piss off, they're hardly going to want to sit down and read a book, are they? ("Look, Spot, see Spot Run" gets a bit repetitive after the tenth time)

          2. MachDiamond Silver badge

            Re: 10-50 seat commercial passenger aircraft are a thing.

            "I think screening rules differ for smaller and/or private aircraft. Also, any screening would much quicker if (a) there's 20 passengers rather than 200 and (b) there's a few dozen flights per day out of a small airfield rather than a few dozen flights per hour from a major airport"

            For small operators of "flight on demand" services, screening isn't required. Any regularly scheduled flight of the public requires screening and also any aircraft over a certain size. I was aghast when a group of business people rented a 737 and visited a nearby airport (non-commercial) and the TSA had to bus a gaggle of gropers out to fondle everybody before they reboarded the plane. These were all high powered business leaders traveling together on a plane they had rented just for their trip. A state governor was also part of the party.

            I would love to be able to get closer to my destinations than a commercial airport provides. In the US there are small airports all over the place. One problem is that screening requirement for regularly scheduled flights and there are regulations/permits/requirements for an airport to be able to have non-private passenger service. In many cases, it isn't worth it financially for the airport to get all of the permissions and put in all of the upgrades to make it worthwhile.

            I just looked into this after seeing an add for a flight subscription service that uses 8 passenger single propeller planes for flights on demand. It's about US$2,000 month for unlimited trips and they only travel to certain airports within the state that have a Part 1XX (can't remember the number) permit.

  7. Brian Miller

    Catapult takeoff?

    What if the airplanes used a catapult mechanism for an assisted takeoff? Then batteries might be adequate for short-hop commuter distances.

    1. Flakk Silver badge

      Re: Catapult takeoff?

      I like the idea, but the mechanism would either have to be incredibly long, or the passengers would have to endure 3-4g at take-off.

      1. Dave 32

        Re: Catapult takeoff?

        Darn, y'all beat me to the catapult takeoff idea. Oh, well, great minds think alike, and all that.

        As for the 3-4 gs, I've personally experienced a sustained 3.5Gs (courtesy of a NASA centrifuge), and, while not what I'd call comfortable, it wasn't exactly painful (It did make me want to toss my cookies when I turned my head, although I was able to suppress the urge, just barely.). Still, that was back while I was still rather young and in good physical shape. I'm not sure an octogenarian, or someone with heart problems, would fare nearly as well.

        Dave

        P.S. I'll get my coat. It's the one with the "Astronaut Training Guide" in the pocket.

      2. annodomini2

        Re: Catapult takeoff?

        It's 3-4g on a Carrier as the runway is short.

        If it could use the same launch profile as if there was no catapult (i.e. just get it to take off speed), there must be some savings there.

      3. Number6

        Re: Catapult takeoff?

        No reason you couldn't put a long steam catapult down the middle of a runway and have it take a long time. I'm sure with modern computer power they could find a way to control steam input at various points to give an acceleration profile similar to what gets used now.

    2. Eddy Ito Silver badge

      Re: Catapult takeoff?

      Getting off the ground is one thing, the climb to altitude is another. Let's take an ERJ 135 (PDF) which carries 37 passengers as a comparable example. For simplicity, let's assume it's at max takeoff weight, 20 tonnes, and the altitude we want is 10 km. The potential energy we need to put in is:

      PE = m·g·h = 1e4 m · 9.8 m/s^2 · 2e4 kg = 1.96e9 J = about 3.5 to 4 tonnes of battery.

      Notice that the max usable fuel from the PDF is a tick over 4 tonnes for the ER and a similar tick over 5 tonnes for the LR model. Also note the battery didn't get you off the ground, it didn't get you up to speed, it doesn't maintain 0.75 mach, it doesn't move the jet 2,400 km (ER) to 3,200 km (LR), and it leaves no reserve to come back down. It'll be a short hop indeed.

    3. Chris G Silver badge

      Re: Catapult takeoff?

      Wrap the passengers in foam and launch with a railgun, use folding glider wings so that once it is in the air it can deploy them and use an auxilliary battery powered prop something like a powered glider.

      Alternatively, stop being stupid and use a real aeroplane with proper engines and fuel.

      The perfect battery on the horizon is going to be there for quite a while yet.

    4. Francis Boyle Silver badge

      Re: Catapult takeoff?

      I was thinking along the lines of a White Knight style carrier aircraft to take the electric plane up to a decent altitude before sending it on its way. Technically feasible, probably but I don't for a moment think it would be practical.

  8. Anonymous Coward
    Anonymous Coward

    Kerosene: 46 MJ/kg

    Batteries: 0.5 MJ/kg

  9. I just wish to be anonymous.

    Unless batteries vastly improve, it'll never take off.

    1. Anonymous Coward
      Anonymous Coward

      Unless batteries vastly improve, it'll never take off.

      No matter, airliners full of planet saving vegan cyclists will be able to taxi all the way to their destination, knowing that no polar bear cubs were drowned.

    2. hellwig Silver badge
      Trollface

      I see what you did there.

    3. JassMan Silver badge
      Trollface

      Unless batteries vastly improve, it'll never take off.

      I can see why why you wanted to remain anonymous. There are already fully electric planes in full production. One example is the Pipistrel - http://www.pipistrel.si/plane/alpha-electro/overview. Admittedly at the moment the range is limited by 1hour flying time, which is presumably why Boeing are working on the hybrid route. Airbus have also had a fully flying "eFan" prototype for over 2 years and announced a year ago that they were also entering the small commercial arena - https://www.flightglobal.com/news/articles/airbus-considering-19-seat-hybrid-electric-aircraft-427715/.

      Looks like Boeing are playing catchup. Farming out to a smaller developer is probably more a matter of agility rather than risk avoidance (but that was probably factored in).

    4. Suricou Raven

      Oh, it'll take off just fine. The issue is keeping it in the air for more than ten minutes.

  10. handleoclast Silver badge
    Coat

    Big Problem

    The really big problem here is that the governments will require the airlines to put the batteries in the cargo hold in a discharged state.

    1. bombastic bob Silver badge
      Flame

      Re: Big Problem

      actually LiPo batteries are MORE DANGEROUS when they're discharged... (they tend to gas, expand, maybe blow up, etc. )

  11. Anonymous Coward
    Anonymous Coward

    A long way to go to catch up with Siemens

    Interesting that also today Siemens has announced a record breaking event with their electric aircraft.

    http://newatlas.com/siemens-airbus-electric-plane-world-record-glider/48806/

    And for those that are interested in the power plant (electric motor)

    https://www.siemens.com/innovation/en/home/pictures-of-the-future/mobility-and-motors/electromobility-electrically-powered-flight.html

    1. Martin Gregorie Silver badge

      Re: A long way to go to catch up with Siemens

      Yep, so it can tow an LS8-neo, fitted with 15m wings by the look of it, to 3000m in 78 secs. That's great, and fast too, but as it has a max flight time of around 15 mins, how many gliders can it tow to, say, a more typical 800m before it needs a recharge and how long is that going to take?

      In any case, assuming its recharged from the mains, by the time you take into account transmission losses, the proportion of the electricity generated by fossil fuel and the generator's thermal efficiency, just how much greener is it than fitting a plain old Lycoming flat six and burning avgas?

      Don't get me wrong, its nice engineering but I have severe doubts about its practicality as a tow plane compared with, say, a Robin GR-300 fitted with normal towing equipment (4-blade 'climb' prop and silencer) or whether the electric drive is much quieter, given that much of the noise comes from the prop.

  12. Your alien overlord - fear me

    Boring but

    Extra (makers of stunt planes) has an electric plane which is currently breaking records and one of their mouthpieces is going on about putting 6 of their engines in 19 seat commercial planes. It sounds like they are well into breaking into the commuter market.

  13. Anonymous Coward
    Anonymous Coward

    point of information

    Battery aircraft are fine on power to weight, just abysmal for energy to weight.

    a hybrid would use fuel for cruise, battery for takeoff.

  14. Steve Todd

    The important word here is Hybrid

    A small turboprop can burn 70 gallons of jet fuel per hour. Commercial aircraft tend to need two of them. A single generator, with a battery to handle surge demands and as backup, driving two electric motors, may make a fair bit of sense. Considering you need much less power in a cruise then even more so.

    1. annodomini2

      Re: The important word here is Hybrid

      The other advantage of being a electrical generator instead of a gas generator is it can operate in the peak efficiency zone of the engine more of the time, which with many Gas turbines is usually quite narrow.

  15. the Jim bloke Silver badge

    Think it was in one of Jerry Pournelles "There will be War" anthologies

    An essay on a long duration (weeks to months) flying sky fortress - powered by orbital solar collectors beaming power to collectors on the giant flying wing. Leaving aside why you want a flying fortress if you already have orbital death rays - sometimes you will need to intervene physically and send in the drones prior to burning the place to bedrock...

    Anyway, that 80's essay in a sci-fi anthology seems much more technically grounded and feasible than what these guys are talking about.

  16. John Smith 19 Gold badge
    Unhappy

    BTW 3g is what people on a modern roller coaster ride can experience

    IIRC back pre unification the West German govt did fighter pilot training, then tested pilots in a centrifuge. Downside was by that point they'd already had the super duper expensive fighter course and might wash out.

    The East Germans first move was to send them on a roller coaster. If they didn't barf (or barf too badly) then they got the training.

    Still think a catpult takeoff is a bad idea.

    I'll note the maximum power demand is likely right at the start, to overcome the rolling resistance of the fully weighted plane, and electric motors are very good at reaching full torque pretty fast.

  17. Anonymous Coward
    Anonymous Coward

    typical VC BS

    Makes you wonder how their brains work...

    Hey, I have a great idea! We'll just build smaller planes that are super efficient and can go from point-to-point instead of using hub and spoke. Sure, the engineers are complaining about nerd stuff like energy density, but if I just hire the good engineers like Scotty, they'll fix that. Gosh, it's a good thing I'm such a business genius, everyone else was just too stupid to think of the idea of a rechargeable plane.

  18. Kevin McMurtrie Silver badge

    Based on a true story

    Boeing has been researching hybrid planes for a long time. It's pretty much the same idea as hybrid cars - narrowing the operating range of a fossil fuel engine to where it's most efficient and making up the difference with an electric system. A bonus is that short trips have a higher percentage of their time on battery power. Being able to put little electric engines anywhere can help performance too.

    The question is why Boeing is handing over development to another company rather than doing it themselves. It seems like an attempt to avoid risk.

  19. scrubber

    Energy density

    Anti matter will sort it all out, once they find where it all went. (See next story)

    As for dumb VCs, bribe thinking about investing in hyperloop should be fired, that is the most ridiculous idea since self filling water bottles.

  20. Androgynous Cow Herd

    Brilliant

    Next up: The solar powered submarine

    1. Jay 2

      Re: Brilliant

      Well I believe WWI/II era subs were either fully 'leccy or (sort-of) hybrid, so as long as said sub had some very good batteries, very good solar panels and some nice clear weather it could be possible... though maybe not too viable.

      1. Suricou Raven

        Re: Brilliant

        Hybrid. Diesel engines and batteries. The diesel engines could only run on the surface, as they needed a lot of air, so they'd be used to charge up the batteries. Then when it was time to go stealthy, they'd switch to batteries and dive. They could also run a lot faster on the surface. WWII subs actually didn't go underwater very much - it was only for stealth and attacking, due to the limited dive duration and the reduction in speed.

    2. DJO Silver badge

      Re: Brilliant

      Next up: The solar powered submarine

      That actually could work!

      Have a football field sized neutrally buoyant sheet of solar cells that could be towed behind the sub when cruising close to the surface and rolled back in when going deeper.

      But probably more hassle than a simple old fashioned nuclear generator.

  21. naive

    Far from being an aviation engineer, it seems there could be something to this concept.

    A popular engine like the CFM56, used in 737's, weighs over two tons.

    So a 737 has in total 4 tons hanging from its wings.

    Anyone who had the opportunity to look at the internal wing structure of a commercial airliner will notice that its construction looks like it was made by the same people who built the Titanic, endless sheets of metal riveted together with massive struts.

    A bus sized Hybrid plane would need two relatively light electric motors, a diesel generator, and a few batteries to meet MTOW requirements. If supplemented with a wing design that enables good glider capabilities, it could be a great solution for short distance travel between cities at speeds around 200mph. The electric engines allow for airports so close to houses where a CFM56 on full throttle would blow windows out of their frames.

  22. JeffyPoooh Silver badge
    Pint

    Electric Airplanes and The Take-Off Problem

    Solution: some sort of catapult, rope launch or rolling platform. e-Aircraft could end up at 1500-feet before using any of its own battery energy.

    I was looking at FlightRadar24 the other evening. It's amazing that there can be, for example, well over 100 of just the A380 aircraft type that are simultaneously airborne.

  23. Overflowing Stack

    All these people saying that it couldn't work because the current energy density of batteries is far lower than plane petrol. It's pretty windy at 40,000ft, have you considered that they may fit the thing with wind turbines?

    I'll get my coat.

  24. The Nazz Silver badge

    Well, it worked for Trolley buses.

    Couldn't they just hook a cable to the nearest high voltage power transmission cable/network and run the juice from that? Some of these are c400,000 volts*

    Should allow a wide range of routes, (though obviously not so much overseas)**

    *I am obviously not an electrical engineer, or indeed any other sort of engineer.

    ** For Europe, a longer cable for crossing the Channel could be used.

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