back to article Giant solar-powered aircraft to begin cross-country flight

The photovoltaics-powered Solar Impulse HB-SIA aircraft has arrived at the NASA Ames Research Center in Silicon Valley's Moffett Field to prepare for a flight across the US. After it has been offloaded in pieces from its Boeing 747-100 transporter, the Swiss-made HB-SIA will be reassembled in a Moffett Field hanger, then …

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  1. Don Jefe
    Thumb Up

    Neat!

    I can't wait until it comes to D.C. It'll be great to see it in person.

    1. Anonymous Coward
      Anonymous Coward

      Success

      Will ultimately be dependant on the weather, something that can only be predicted with inaccuracy. If the wind blows in the wrong direction he may find himself in a hover, or worse going backwards.

      Who's betting his first stop will be Hawaii?

      1. Mage Silver badge

        Re: Success? Weather

        This was the problem with the US Airship "aircraft carriers". They were destroyed by weather.

    2. JeffyPooh Silver badge
      Pint

      Re: Neat!

      It is DC already.

      Get it? Sorry...

  2. VeganVegan

    At the risk of being too pedantic,,

    Beyond just being tired, what does the pilot do about food and water, and what about going to the bathroom?

    1. armyknife

      Re: At the risk of being too pedantic,,

      Yellow Ice.

      1. M Gale

        Re: At the risk of being too pedantic,,

        And brown meteors, one presumes?

        Either that or a bucket full of the blue water under the seat.

        Though if weight is that much of a concern... adult nappies?

        The mind reels back in horror contemplating it. I wouldn't want to be the people opening the hatch on the ground.

        1. John Smith 19 Gold badge
          Boffin

          Re: At the risk of being too pedantic,,

          Well when the 2 person Voyager team flew around the world they used the tech of the Gemini programme with bags they dropped over the side when over open country.

          Outside of general aviation things get a bit involved for long flights but they have to be faced.

        2. JeffyPooh Silver badge
          Pint

          Re: At the risk of being too pedantic,,

          http://en.wikipedia.org/wiki/Gemini_7

          14 days, two men in a can.

    2. Kharkov
      Trollface

      Re: At the risk of being too pedantic,,

      Ah, this is probably where they've come up with a nifty idea to raise additional capital.

      Farmers all across the nation will pay a small amount each to have their fields fertilized. So the GPS turns on the green light, the pilot sticks his posterior out the hatch and... bombs away!

      Can't wait for the movie...

    3. Anonymous Coward
      Anonymous Coward

      Re: At the risk of being too pedantic,,

      ... and as it spends much of it's time above 12000 ft, what about all the oxygen that the pilot needs?

      1. Richard 12 Silver badge

        Re: At the risk of being too pedantic,,

        Same as on a commercial jet - the low-pressure external air is compressed to create cabin air.

        It's obviously a special compressor on an airscrew craft as there isn't any bleed air from the jets, but it's still pretty simple.

    4. This post has been deleted by its author

    5. James Micallef Silver badge

      Re: At the risk of being too pedantic,,

      In fact, why have a human pilot at all? Remote control + semi-autonomous and it REALLY could stay up forever. Could be very useful for comms links in remote areas etc.

      Even if the ultimate aim is to develop this to a point where it can carry passengeres, the pilot is still extra weight. Stick 2-4 passengers in and pilot it from the ground.

  3. Malcolm Weir Silver badge

    Units and comparisons...

    At the risk of point out El Reg's own guidelines, altitude of aircraft (especially, but not exclusively when operating in US and European airspace) are reported in FEET. Feel free to quote meters for those who like such things, but the applicable unit is FEET!

    And, while we're at it, a two class 747-400 doesn't really carry 524 passengers; to get that many people in, you need to use short-haul style "business class" seats, the sort of thing that British Airways calls "Club Europe". For serious long-haul flights, which is what the 747-400 is designed for, a more typical two-class layout yields something like 406 passengers (e.g. the Qantas 747-400 fleet here: http://www.qantas.com.au/travel/airlines/aircraft-seat-map-boeing-744/global/en describes a variety of seat plans, all in the 350-406 passenger range. Plus, of course, about 20 crew.

    1. Liam Thom

      Re: Units and comparisons...

      And speeds should be in knots. km/h is not metric and is an abomination. If you must use metric then m/s would be correct.

      1. firefly

        Re: Units and comparisons...

        Km/h for air or sea travel is indeed an abomination but not for the reason you stated. A knot is one nautical mile per hour, and a nautical mile is one minute of an degree of latitude. A pilot will know that for every 60 knots of groundspeed they travel east (or west), they will travel 1 degree of longitude every hour.

        It's one of the few 'old' measurements that makes better sense than metric, and quite frankly any change towards km/h should be resisted.

        1. Anonymous Coward
          Anonymous Coward

          Re: Units and comparisons...

          "A knot is one nautical mile per hour, and a nautical mile is one minute of an degree of latitude"

          Actually no. A nautical mile is defined as exactly 1852 metres.

          "A pilot will know that for every 60 knots of groundspeed they travel east (or west), they will travel 1 degree of longitude every hour."

          I think you'll find you're missing a cos(φ) somewhere in there.

        2. AeroSpike

          Re: Units and comparisons...

          Almost right! But traveling East or West at 60 knots will move you 1 degree of longitude only if you are flying on the equator. Any non zero lattitude will give you more than a degree, 1 / cos( Lat ) degrees actually.

        3. Anonymous Coward
          Anonymous Coward

          Re: Units and comparisons...

          I presume you mean latitude? As longitude is /very/ wrong.

          -D

          1. graeme leggett Silver badge

            Re: Units and comparisons...

            But if possible flights take a great circle route so calculating flight speed in degrees of that circle makes sense.

        4. James Radley
          Headmaster

          Re: Units and comparisons...

          Not quite true. I degree of longditude is only 60 nautical miles at the equator. As you go towards the poles. the longitudinal lines get closer together until they meet. Latitude lines are 60 miles apart in all cases though, so the statement "A pilot will know that for every 60 knots of groundspeed they travel north (or south), the will travel 1 degree of latitude every hour." is correct.

        5. Bitbeisser
          Thumb Down

          Re: Units and comparisons...

          Sorry firefly, but that attempt of reasoning is simply rubbish. I am pretty sure that

          a) the vast majority of flight is not in a straight east/west (and vice versa) direction, and

          b) the actual distance on the ground for a degree of longitude varies with the latitude. The internationally defined 1852 meters per nautical mile is only valid for a distant straight along the equator.

          Once again, using the more sane metric values makes much more sense than using another set of Fred Flintstones units...

  4. Anonymous Coward
    Anonymous Coward

    So this has a real pilot not a Lego/Playmobile one?

    Unless you pick the right stuff.........

  5. itzman
    FAIL

    I love stuff like this..

    Because it proves so conclusively why renewable energy is such a load of pants.

    Right at the bleeding edge of technology, a renewable aircraft the size of a jumbo, can just lift one man, and if lucky, get up to 30mph.

    I hope he doesn't hit a downdraught. or CAT.

    "Engineers are confidently predicting that a wind powered vessel 'could sail indefinitely, at 2-3 knots average, depending on weather conditions"

    WOW!

    "Greenpeace says 'walking will be the way we travel in the brave new green world, walking needs no expensive roads, and if there is access to enough brown rice and hiking boots, can be carried on almost indefinitely",

    1. Anonymous Coward
      Anonymous Coward

      Re: I love stuff like this..

      Seems to me the tech will eventually be put to use in some kind of drones rather than for passenger/piloted flights.

      1. John Smith 19 Gold badge
        Black Helicopters

        Re: I love stuff like this..

        "Seems to me the tech will eventually be put to use in some kind of drones rather than for passenger/piloted flights."

        What makes you think it hasn't already?

      2. Aeolus

        Re: I love stuff like this..

        Yep. See:

        http://en.wikipedia.org/wiki/Qinetiq_Zephyr

        1. Ted Treen
          Devil

          Re: I love stuff like this..

          What I love most is the thought of all those twisted little goblins in HM Treasury trying to work out how the hell they can quantifiably tax sunlight.

          HeHeHe...

          1. Steven Roper

            Re: I love stuff like this..

            "...how the hell they can quantifiably tax sunlight."

            The same way they've taxed fresh air in Australia - aka the "Carbon Tax". Trust me, the greedy fuckers will find a way.

    2. Anonymous Coward
      Anonymous Coward

      Re: I love stuff like this..

      So the few feet the first airplane made were indicative of the future of flight? Yeah, get a brain.

      While not small, it manages further than the first flight did. So it's again a proof of concept.

    3. Voland's right hand Silver badge
      Devil

      Re: I love stuff like this..

      "Engineers are confidently predicting that a wind powered vessel 'could sail indefinitely, at 2-3 knots average, depending on weather conditions".

      Bollocks.

      Last time I remember the "pinnacle of wind" - the steel hull, steel mast windjammers from the end of the 19th century outsailed with ease german cruisers at the start of WW1. Germans could not catch up even with the sorry hulk which was Cutty Sark by that time (it had a mast missing and had 1/4 of the crew it needed).

      The speed of these 4-5 mast monsters was ~ 15 knots. That is in fact on par with most cargo fleet till this day (only ferries and some container ships sail faster and only on short haul). It was not speed or carrying capacity that terminated the windjammer fleet - it was a combination of the canals (Panama and Suez) and manpower costs.

      The saddest part about attempts to reintroduce windpower in ships is that none of it gets even close to where we were 120 years ago. Parachute sails/kites my a**e. A proper "salty dog" rig of the kind which took the route around cape Horn to California or Cape Good Hope to Australia in the 1890-es can run circles around it any day.

      The only reason for wind to be slower in the end-to-end play is that it requires different routes. You usually cannot sail straight from A-Z. That is why the canals decimated it in the first place. From that perspective, considering where the Suez/Middle East situation is going lately we will be considering wind again very soon (same as we did during the previous Suez problems).

      1. JeffyPooh Silver badge
        Pint

        Re: I love stuff like this..

        World's biggest ship (under construction now) will be going 17.5 kts, to double fuel efficiency.

      2. itzman
        FAIL

        Re: I love stuff like this..

        in a far wind yes, a sailing ship was fast.

        The problem comes when you look at the average journey time between ports. A tramp chugging at 7 knots could provide a reliable service in far less time than a clipper. Whose route would be longer, having to seek and find the trades, and the westerlies, and often being becalmed in between.

        The myth of 'wind is fast' is similar to the myth surrounding wind turbines. Just quote the top speed and forget the abysmal average and pretend its superior.,

        "Nevertheless, the Sovereign of the Seas, the Cutty Sark and other fast sailing ships did not average such speeds. The Cutty Sark set a record for a passage from Plymouth to Sydney of 72 days, when a fast passage was considered to be anything around 100 days. Even on the record setting voyage, however, the Cutty Sark actually only averaged around 8 knots. The ships which made “fast passages” of 100 days averaged around 5 knots. The Flying Cloud on her record setting voyage between New York and San Francisco ol 89 days, likewise averaged around 7.5 knots.

        The reason that average speeds of so many clipper ships were often low had to do with the doldrums, the regions of light air just South of the Equator. Even the fastest sailing ships are slow when the wind is light or non-existent. But what of ships that did not have to traverse the light air of the doldrums? The fastest passage ever recorded by a sailing ship between New York and Liverpool was made by the clipper Red Jacket in 13 days, 1 hour and 25 minutes. During the voyage she reached speeds of over 17 knots. Nevertheless her average speed was around 10.5 knots.

        These are the record speeds set by the fastest sailing ships. It is probably fair to say that most sailing ships in the 19th and early 20th centuries averaged between 5 – 8 knots on average depending on the size of the ship, the route and the weather. There are nothing wrong with these speeds but they are not comparable with container ships, even those slow steaming at 12 knots."

        ( http://www.oldsaltblog.com/2012/09/are-modern-ships-slower-than-sailing-ships-probably-not/ )

        1. Don Jefe
          Meh

          Re: I love stuff like this.. @ itzman

          You are sort of correct buy have made the error of failing to consider the rest of the environment, the structural limitations of the ships and the fleshy crew.

          Wind is not, and has never been, the sole bottleneck in vessel speed. The ships were more limited by the state of the seas than the winds themselves. It is/was terribly easy to exceed the hull speed on a sailing ship (on a modern vessel with deeper keels and efficient sails almost no wind is necessary to scoot along) but you get into stresses (hull and mast breakages, cargo displacement, loss of steerage, and generally unacceptable levels of throwing humans overboard/breaking them). The voyages could have been much faster but the ships fell apart from the sheer beating they took. Steel hulls helped a lot with this as did internal power which made maintaining steerage easier, but even the largest ships afloat today can't overpower the power of the seas and are regularly forced just to point into the storm, try to keep her into the waves and hope.

    4. Rol Silver badge

      Re: I love stuff like this..

      and when the new ion drive planes that can travel faster than the Earth rotates, start whipping round the globe, always in sun, you'll see how short sighted, short sighted, really can be.

      1. TechnicalBen Silver badge
        Headmaster

        Re: I love stuff like this..

        Ion drives don't work like that.

        1. Rol Silver badge

          Re: I love stuff like this..

          Not yet.

  6. PM.
    Go

    I , for one, am fascinated with this

    Just like first combustion planes had laughable performance, but looking at them ,someone with vision could imagine their amazing future ...

    Today solar-powered craft can take only 2 passengers and fly at laghauble speed, but imagine thats just first iteration in a row of succesive designs, with a commercial one available in next few years, when solar cells will be much more efficient.

    1. Gene Cash Silver badge
      Stop

      Re: I , for one, am fascinated with this

      "when solar cells will be much more efficient"

      I've been hearing that refrain for decades, along with "when batteries will be much more efficient/lighter/smaller/less dangerous"

      1. Don Jefe
        Meh

        Re: I , for one, am fascinated with this

        Efficiency in both PV and batteries has increased dramatically, even in the last decade.

        Fear of risk, vested interests, and pure ignorance have been a major component in developing both. No one wants to try and make things better so the Govt has to step in and subsidize stupid ideas hoping at least a few will work out. It is nice to see someone pushing current limits with the plane.

        1. Mage Silver badge

          Re: I , for one, am fascinated with this

          Efficiency has increased somewhat and not as much as the hype. But interestingly not life. Also curiously if we consider volume and not weight NiMH is as good as Lithium when new and after 6 months of cycles may beat Lithium of same volume on capacity. Easily beat on life. Much heavier though.

          Water heating at home from solar is still far better than photovoltaic and will repay costs without subsidy. The photovoltaic only repays cost for user if subsidised.

          A photovoltaic aircraft is likely only suitable as high altitude "drone". Even at 100% efficiency the photovoltaic aircraft would not have commercial carrying capacity nor cope with weather to land and take off.

          1. Anonymous Coward
            Anonymous Coward

            Re: I , for one, am fascinated with this

            Solar hot water is NOT still far better economically than solar PV. The optimistic scenarios for solar thermal ignore the fact that if you're not at home using hot water, heating your water isn't very efficient so it looks pretty bad compared to on-demand natural gas water heating. Grid-tied PV can use all the electricity it generates with only 10-15% conversion and transmission losses and it generates power during periods of high demand when spot prices are highest. The thermal over PV view is outdated.

            Back to topic: yes it's primarily a high-altitude drone technology for now, but as thin film keeps improving efficiency and prices keep falling the question is not whether you can have electric airliners but whether there will be a point where you can economically run low-altitude drones in some locations some of the time or add solar to aircraft wings in order and lower long-term overall costs. Fuel is expensive.

          2. Anonymous Coward
            Anonymous Coward

            Re: I , for one, am fascinated with this

            Solar hot water is NOT still far better economically than solar PV. The optimistic scenarios for solar thermal ignore the fact that if you're not at home using hot water, heating your water isn't very efficient so it looks pretty bad compared to on-demand natural gas water heating. Grid-tied PV can use all the electricity it generates with only 10-15% conversion and transmission losses and it generates power during periods of high demand when spot prices are highest. The thermal over PV view is outdated.

            Back to topic: yes it's primarily a high-altitude drone technology for now, but as thin film keeps improving efficiency and prices keep falling the question is not whether you can have electric airliners but whether there will be a point where you can economically run low-altitude drones in some locations some of the time or add solar to aircraft wings in order and lower long-term overall costs. Fuel is expensive and people are expensive.

    2. Richard 12 Silver badge
      Boffin

      Re: I , for one, am fascinated with this

      Solar PV can't ever work for large airliners, here's why:

      The Boeing 787 Dreamliner is supposed to be one of the most fuel-efficient passenger aircraft yet developed.

      It uses two Rolls-Royce Trent 1000 engines.

      A single Rolls-Royce Trent 1000 engine delivers 39,400 kW at takeoff.

      There are two of them, so your batteries have to be able to provide that 78,800kW during takeoff - no batteries can do that, but we'll ignore that for the moment.

      For the sake of argument, let's say 1/4 that at cruise altitude.

      Maximal insolation is 1.3kW per sq metre at the top of the atmosphere.

      Let's give you 100% efficient PV cells. So your aircraft needs to have a PV cell surface area of approx. 15,100 m2.

      Boeing's Dreamliner's total wing area is 325 m2, let's say 650 m2 for the full aircraft (bigger than reality).

      Yet we're still only at 23% of the required power by using 100% efficient cells.

      Oh dear. Not going to work then, is it?

      Like helicopters, this technology is interesting and likely to be useful in specific situations (eg very long loitering drones), but it cannot replace the jet airliner.

      1. Anonymous Coward
        Anonymous Coward

        Re: I , for one, am fascinated with this

        You might not need the power of a couple of RR Trent 1000s. Remember you won't have to be lifting umpteen tons of aviation fuel and its associated infrastructure. Secondly, being on the ground there should be no problem with the acreage required for solar takeoff power. The area of the runway itself feeding electrified rails might be one possible scenario.

        I'm not saying this can definitely work, just saying don't be too hasty writing off a viable solar passenger flight system sometime in the future. After all, bumblebees refuse to believe they can't fly.

        1. itzman

          Re: I , for one, am fascinated with this

          "I'm not saying this can definitely work"

          But I am saying that it definitely categorically cannot work.

          Because I am an engineer who designs builds (albeit smaller) aircraft and flies them.

          I could probably - given the cash - build you an electric aircraft that could break the sound barrier. If you found a magic battery with 100 times the energy density of the best theoretical battery that ever could be produced using any elements that exist in the periodic table, it might even stay up for half an hour doing that.

          But, using wing area to collect sunlight, the mathematics are simple. There simply is not enough power arriving there to give you anything more than the ability to carry the weight of the panels and enough battery after dark to keep the aircraft aloft at a very slow and massively vulnerable speed in a structure that would almost certainly fail commercial tests.

          Its one of the abiding myths perpetrated by the eco lobby that 'technology will improve' And so it will, but there are always theoretical limits, and only if you are well away from them is dramatic improvement possible. For example, Moore's law represents strides in technology and miniaturisation of etching on silicon that can produce exponentially more memory and circuitry on a single silicon die. But you cannot go to smaller components than the size of a few atoms. If you want more you have to look at a totally different technology.

          This isn't he start of a new technology, this is - rather like a formula one car - the absolute bleeding edge of an old technology. Heavier than air flight, batteries, solar panels and electric motors. All well understood, all getting very close to 'as good as it gets' .

          The problem is there are no new technologies on the horizon. Oh there are claims, but in the end they are all old technologies dressed up to be 'new' and marketed as the next great hope of the future.

          The appalling thing is that we haven't had any significant new technologies in the last 50 years.

          atomic and Quantum theory in the early 20th century gave us atomic power, lasers and the semiconductor.

          And that's the only stuff I can think of that was a total breakthrough. Everything else is simply refining stuff that was already known about. Leonardo could have built an aeroplane if someone had given him a moped engine and a few gallons of fuel.

          As is this.

          Now if someone were to hand me a 'quantum engine' that would silently destroy and turn matter directly into electrical energy..without destroying me, I could build you a ship to take you to the stars..well the nearer ones anyway..

        2. Richard 12 Silver badge
          FAIL

          Re: I , for one, am fascinated with this

          Instead of umpteen tons of fuel, you lift umpteen tons of batteries. No change there.

          You also missed the point spectacularly - the thought experiment was very simply "Can solar power a commercial aircraft at cruise", and the answer is "No, there is not enough insolation".

          - BTW, The 'bumblebees' thing is irrelevant - we're talking large passenger aircraft, not microscale insect sat on sticky, turbulent air. Yes, we know exactly how bumblebees fly and have done for at least a decade. They aren't solar powered either, they run on nectar and pollen.

          1. graeme leggett Silver badge

            Re: I , for one, am fascinated with this

            On the plus side , at the end of a flight you would still have those tons of batteries to fill again

            On the minus side, you would still have those tons of batteries and need stronger undercart for the heavier landing.

      2. GrantB
        Boffin

        Re: I , for one, am fascinated with this

        A 787 is designed around the (slightly less powerful) General Electric GEnx or RR Trent engines and (fossil) fuel powering them.

        Whatever a theoretical Solar PV powered 'large airliner' looks like, it won't be a 787. As others have already pointed out, on take off (at several hundred knots) it is accelerating and lifting tonnes of fuel - in fact if it had to perform an emergency landing it would have to dump something like 50,000kg of fuel. The two engines also have to have significant power reserves to allow controlled flight on one engine. Critically, the flight profile is designed around that power, and therefore the profile is based on the need to climb as quickly as possible to an optimal cruising speed and altitude where the jets operate most efficiently.

        Compare with a theoretical solar aircraft - it needs far less power to accelerate and climb in comparison. It can operate much lower and slower, possibly even changing flight profiles so that flights are grouped around mid-day take-off and evening landings. So power (and therefore fuel cost) requirements are far less. Surface area would also be significantly greater - I assume any aircraft using PV to boost range would use a flying wing or airship design to give a comparatively massive surface area. Travel would be classic airship style - i.e. more like a cruise liner than stuffing people into a tin can and flying them at Mach 0.85 from airport to airport. These days nobody can book a trip on a super-sonic airliner, (maybe with the exception of Virgins Space Ship one) but many people travel by cruise liner and that is quite a profitable industry, traveling slowly between sunny island destinations..

        I am still not sure PV airliners would be very feasible with current or near future technology (assuming we don't have have Diamond Age style tech in the near future), from a cost/benefit point of view. Commercial air-line flights did start off with aircraft such as classic DC-3's that were powered by a few piston engines producing a few hundred KW, so 78,000KW is not a reasonable requirement.

        As you say, this technology is interesting and likely to be useful in specific situations such as very long loitering drones or satellite replacements, rather than being applied to trying to lift a few hundred tourists from A to B, but using a 787 for back of the envelope calculations is not reasonable.

        1. Richard 12 Silver badge

          Re: I , for one, am fascinated with this

          Of course a 787 is reasonable.

          As would a 777 or 747, but the 787 is supposed to be the most efficient.

          Yes, the first commercial airliners carried about 20 passengers and flew much slower.

          However, the modern traveller won't go back to that!

          There isn't the airport capacity for many more aircraft, so they have to keep similar aircraft capacity - 200-400 passengers - unless you want international travel to be the preserve of the super-rich.

          And would you be happy for the transatlantic flight times to double as well?

          Not to mention that transatlantic at low speed also requires that these aircraft can still fly at night...

          1. GrantB
            Meh

            Re: I , for one, am fascinated with this

            Any big multi-jet airliner, including the 787 is not a reasonable comparison for the reasons given in my original post. Any theoretical electric powered airliner will have to be radically different

            Sure the first commercial airliners carried about 20 passengers and flew much slower, but there descendants are still in operation world-wide. I recently flew (commercially) on a 19-seat Beech 1900D turboprop. (http://www.airnewzealand.co.nz/seat-map-beechcraft-1900d). That flight was one in which a 787 would have been less than efficient.

            In other words, many smaller, slower commercial airliners have their niche.

            >However, the modern traveller won't go back to that!

            Yes they will if the price is right.

            30 years ago people could travel faster in airliners like the Concorde. People overwhelmingly choose flights on slower, cheaper aircraft. People also choose to take a cruise on a ship rather than fly, or simply don't have a choice on some short haul routes such as island hopping where small turbo-prop aircraft are the right choice. Jeremy Clarkson lamented that ships and aircraft generally travel slower these days as cost, fuel economy and emissions become more important than speed in getting from a to b. Teleconferencing is always going to be faster than business travel.

            Banging on about airport capacity misses the point - when your take-off speed is closer to 50knots than a few hundred knots and massive runway required for a 787, your air-port requirements change a lot. I am sure, Airbus 380's and the like will continue to haul big groups of people across the Atlantic in bulk for a very long time, but for island hopping, many airports are far from capacity, and near silent, slower electric aircraft could fill in gaps nicely.

            >And would you be happy for the transatlantic flight times to double as well?

            >Not to mention that transatlantic at low speed also requires that these aircraft can still fly at night...

            Wouldn’t worry me.

            I live in NZ and of the last few dozen commercial flights I have flown with various airlines , non were across the Atlantic and most were relatively short ranges during the day.

            Given a significant proportion of a ticket goes on fuel, I would be happy to save some money and fly a slower, greener, electric aircraft if airlines had them. Would love to fly on a modern air-ship the size of the R101 on day rather than being packed into another 737 or similar.

            I can’t imagine seeing a purely solar powered aircraft in commercial use the near future either, but some small steps like taxiing an A380/B747 via a few KW of electric motors driving through the undercarriage, rather than using big turbo-fans (~5MW at taxi speed). In the longer term, who knows; but it won’t look like a 787.

    3. John Smith 19 Gold badge
      Meh

      Re: I , for one, am fascinated with this

      "Just like first combustion planes had laughable performance, but looking at them ,someone with vision could imagine their amazing future ..."

      True but they had a reason to innovate which drove many cycles of engine and structures development.

      It was roughly 24 years between the Wright brothers at Kill Devil hill and Lindberg flying the Atlantic.

      BTW I upvoted you. Improvement is possible, the question is how much will people want?

      1. itzman

        Re: I , for one, am fascinated with this

        If you look at the numbers, a WWII fighter had about 75W/lb. A 450mph hawkerTyphoon at the end of WWII had 150W/lb.

        There was no amazing leap forward in engine design: The engines just got about twice as good - the key was in the ability to build BIGGER engines. around 100bhp bought you a top of the line WWI fighter. 1000bhp nets you a spitfire.

        And in accepting the far higher landing speeds that the massive increase in speed necessitated.

        A WWI biplane nips into the air at 50mph or less, and a 100 yards of runway.

        A 747 needs to be doing the best part of 150mph and needs two MILES of runway.

    4. itzman
      FAIL

      Re: I , for one, am fascinated with this

      "with a commercial one available in next few years, when solar cells will be much more efficient."

      I love a good larf when non engineers prattle on about subjects they dont understand.

      Weight and power for heavier than air flight are inextricably linked. it takes about 10W/lb to just stay in the air floating. It takes about 30W/lb to actually be able to climb at anything other than a snails pace, and most aircraft are in te 70-150W/lb area which allows them to fly out of trouble, get up to cruise quiclkly and so on.

      This aircraft already has a third of its weight in lithium batteries to get the peak power to actually take off. At night it depends on those to keep it aloft. Solar panels are already better than 20% efficient, and the wingspan of this - needed to actually generate enough to stay up - is already bigger then a jumbo jet. once the batteries motors and structural weight are taken into account, it has just adequate margins for a single passenger.

      It would need solar cells that generates at least 30 times more to be any commercial proposition.

      You cant change the insolatin and you cant get 60-0-% efficient batteries, no matter how smarty you are.

      I've been flying electric (model) aircraft for years. I know all the formulae. I've used the best technology there is. I can outperform fuel engines. For three minutes. Then the battery is flat and its time to land. And solar panels of the same size as the aircraft if they were 100% efficient still would not have the ability to recharge them faster than they need to be drained.

      This is an amazing feat, don't get me wrong - its a very large model electric sailplane which has been massively compromised in every way to get its weight down, and the solar panel area up. IN order to achieve flight at all. The slow speeds reflect that.. the slower te speed the slower the sink rate and the less power you need to get the machine up, and that means building for a very low wing loading - that also gives you the largest area of wing to put the panels on. Been there done that to achieve ultra low power flight, BUT the flip side is it will inevitably be dog slow - speed takes power - and it will crumple like a wet tissue in turbulence. Nor will it be able to run away from it.

      I t is suffering from exactly the same problems as airships. Yes they use very little fuel and stay aloft indefinitely, but with the issues of buoyancy/payload being insoluble except by making them bigger, and the strength of materials versus their weight sadly remaining constant, you necessarily and inevitably end up with a structure that is large and fragile. Most airships didn't catch fire and crash in a blaze: Most got ripped to pieces by turbulence.

      So its possible to say with absolute certainty that using this technology,. or any derivative of it, no matter how efficient, you will never see a commercial solar plane, ever. There simply isn't enough energy from the sun to fly one.

  7. Mage Silver badge

    Indefinitely?

    My laptop is on its 5th battery pack.

  8. any fule

    Maybe Boeing should talk to these people...

    ... Herr Borschberg seems happy enough to fly in a balsa and plastic aeroplane with 400 kilos of Lithium Polymer batteries, while the 787 has been grounded for the last 6 weeks because of problems with a pair of Lithium Cobalt batteries of less than 30 Kg. I think I'd feel safer in the 787 though.

    1. graeme leggett Silver badge

      Re: Maybe Boeing should talk to these people...

      Electric plane, 1 example, 1 flight, 1 pilot, no passengers

      787, lots of aircraft, 2 pilots, rest of crew, hundreds of passengers on each.

      Balance of risk very different

  9. Zmodem

    if someone made a perpetual generator out of a wind turbine, and found out it works, you could power ramjets with a 6mw turbine, and fly a full size a380 at max speed

    1. Zmodem

      just by putting a few of http://www.spcoils.co.uk/portals/0/Images/EconomyCoils1.jpg inside the jets inside of using the naked burning fuel flame to explode the air

    2. Richard 12 Silver badge
      FAIL

      If wishes were horses...

      Zmodem, if you've got working perpetual motion machine, build it and show it to the US Patent Office.

      I guarantee a working one would make you an overnight multi-billionaire.

      However, you don't, and nobody does. Funding is not the reason, the reason is because they do not work.

      Quite simply - if they worked, Rolls-Royce would be using them. They don't because they don't work.

      1. Zmodem

        Re: If wishes were horses...

        it wouldnt make you a billionaire, no body can patent something in the public domain, which means compition, which means alot of changes in 10 years for planes, cargo ships, no wind farms

        the torque and rpm needed for maximum output is low and the input watts/volts looping back to the motor for the electro magnets is nothing taken from the 325.000 watts generated every 1 rpm of the dynamos 20 rpm that generates the 6.5 Mw

        1. Zmodem

          Re: If wishes were horses...

          still dont get it, even though you can run a remote control car motor of a watch battery

          1. Zmodem

            Re: If wishes were horses...

            probaly why most people who post on here ,. used to work at where ever

            1. Zmodem

              Re: If wishes were horses...

              and they have no shaft power, they are the only type of motor that can turn massive axles, on ships and diggers etc etc,. input watts it all they need for the oposite poles of electro magnets to turn the axle on a direct drive dynamo

              1. Zmodem

                Re: If wishes were horses...

                1> a battery cell, for the initial startup to kick start the motor to the dynamo`s minimum generating RPM

                2>the generated electric passes through the kickstart battery cell, partially recharging and adding more electric that can give more power to the motor bringing the motor up to the dynamo`s maximum generating RPM speed

                3>the loop is then openned to the main circuit to want to power, which if you had a 6.5 Mw turbine dynamo, would probaly be 270,000 watts for every 1 RPM, with 50,000 watts looping back to the motor using any old electric motor without the magnets calibrated to the dynamos torque and RPM,, and a small amount of whats left, recharging the batteries for when you have to start it up again

                which is all better then wind farms, millions of gallons of fuel for combustion generators to power electric motors for propellers on ships etc etc etc

                lake and dam dynamo`s from 40 years ago, generating 5m volts

                1. Zmodem

                  Re: If wishes were horses...

                  you can make them out of a domestic kit like this picture http://s24.postimg.org/wvt4f8qt1/generator.png

                  you need the regulator, because you will not find a good motor that is low torque and low rpm, and most will not go as low os 20 RPM without less watt input

  10. John Brown (no body) Silver badge
    FAIL

    The video is wrong.

    Alcock & Brown were the first to fly non-stop across the Atlantic 18 years before Lindburgh, who made the first *solo* flight across the Atlantic.

    But it does appear to be a US produced video and Alcock & Brown were just foreign colonialist lackeys and not Free US citizens so don't really count in that version of reality.

    Other than that, a great achievement looks like it's in the offing. Good luck to the team.

    1. Daniel Feenberg

      Re: The video is wrong.

      The Alcock and Brown flight was from Newfoundland to Ireland, the Lindberg flight was from New York to Paris, which is about twice as far. The prize offered was for the later route. If the video says "first transatlantic flight" it is wrong, but the xenophobic conclusion of the OP is unjustified.

      1. graeme leggett Silver badge

        Re: The video is wrong.

        Lindbergh (1 person) got $25000 alcock and brown(2 persons)got £10000

        The R34 airship which flew both directions in 1919 and carried 30 or so on board got bugger all.

        But an electric powered airship makes more sense than an electric aeroplane

      2. Munkstar

        Re: The video is wrong.

        http://en.wikipedia.org/wiki/Transatlantic_flight_of_Alcock_and_Brown

  11. Alan Firminger

    More

    There must be a team somewhere that provides all support. I imagine that would be in a twin turboprop aircraft able to operate a communication and control unit either on land or aloft and carrying the service team to wherever needed.

    So what comprises support and mission control ? If anyone knows then perhaps you could post a reply.

  12. Will Godfrey Silver badge
    Thumb Up

    I think some people totally miss the point

    This is more than a solar powered aircraft. What about those wings? How do you make something that long and maintain structural integrity? What do they have to do to keep it stable in the air?

    What about those props? I bet they're a bit special too. They have to perform over a wide range of altitude. Variable pitch not doubt, but what else? How do they get the weight down on the motors yet maintain power? What effect does extreme temperature and humidity have on them (and on the bearings)?

    These are just a few questions off the top of my head. There is a lot of fascinating science in this thing.

    1. itzman

      Re: I think some people totally miss the point

      All old hat stuff to anyone who builds electric model aircraft - which this is, just scaled up to carry a load of solar panels and a pilot.

      The motors are all stock items. Neodymium magnets with three phase coils and electronic commutation and throttling. You can buy all of that for $30 from china, ok the power is up into the $300 -$1000 bracket. The batteries too are stock items, you just need rather a lot.

      The airframe will be probably carbon fibre composite - no other material is as good - so got to a formula one team or aerospace manufacturer for that. The tail looks like its covered in mylar film - tough, airt tight, light and strong enough.,

      The props will NOT be variable pitch, since the speed envelope is small - they will be designed to work at a given airspeed and fixed at that. The extra gains of a variable pitch for landing and takeoff would be totally wiped out by the added weight. They probably WILL be geared, since pulling RPM downs leads to a lot greater efficiency

      In short you can go to any model flying club and see something like this, minus the solar panels, flying perfectly well. For very long periods too.

  13. JeffyPooh Silver badge
    Pint

    Insulating batteries to solve the cold battery problem... Who'd have guessed that?

    "...batteries are heavily insulated to allow them to function at the -40°C (-40F°) temperatures..."

    Hey, what a great idea! Maybe the idiot e-car designers could combine this *brilliant* idea with some tiny low power heaters, smart timers, and adjustable cooling air ducts to almost completely solve the cold battery problem in e-cars. Duh.

    Oh, sorry, I forgot. Insulating batteries is "impossible". LOL.

  14. JP19

    "dependent on local meteorological conditions"

    Nice way of avoiding the word cloudy.....

    1. Dave Bell

      Re: "dependent on local meteorological conditions"

      With the combination of weight and wingspan, it wouldn't take much wind to mess up a take-off or landing. Not just wind speed, but direction.

    2. Alan Firminger

      Re: "dependent on local meteorological conditions"

      Or violent.

    3. Armando 123

      Re: "dependent on local meteorological conditions"

      Yeah, good luck to them when they get east of the Kansas-Missouri border. They're in for rough weather and plenty of cloudcover.

  15. Anonymous Coward
    Anonymous Coward

    "Name"

    Hehe, as soon as I saw the name I knew it would be Swiss (HB Switzerland's radiotelephony prefix).

    The aircraft's name is simply its registration number. :)

  16. Stevie Silver badge

    Bah!

    So no-one told NASA that July is a season of sudden torrential rain in New York, (as it is in Atlanta, Georgia)?

    Or is the phrase "delicate aircraft" some sort of clever euphemism for "extremely robust aircraft"?

  17. Fink-Nottle
    Coat

    Wouldn't it be better to start off with Tuvalu or Andorra and work your way up?

  18. Tony Reeves 1

    A Minor Point

    Think head wind...

  19. Martin Budden
    WTF?

    Science section?

    Why is this fascinating article not included in the Science section? I almost missed it!

  20. Munkstar

    What's the point? Qinetiq have already produced a solar drone that can fly for days (Zephyr), the difference in this aircraft is the passenger/pilot .... one of. Drones I understand, one person sat in it I don't.

  21. imanidiot Silver badge

    Back to the drawing board?

    Assuming the roughly 12 m/s (43 km/h) is also used during decent that means a glide ratio of roughly 1 in 32. Which is abismal for any glider by todays standards. Most achieve 1 in 40 at about 4 times the speed at least! Since the construction details would be pretty similar (Large slender, thin wings stuffed with weight. Water in gliders, batteries in case of Solar Impulse) I have a hard time believing they couldn't get better glide numbers.

  22. Scott Wheeler
    Headmaster

    Re video: a small point, but I wish the USAians wouldn't keep flagging up Lindbergh as the first to fly the Atlantic. The first non-stop heavier than air flight was by Alcock and Brown. Lindbergh did the first solo (and had a more elegant landing).

    1. graeme leggett Silver badge

      Not having a film about it with Jimmy Stewart and lacking a glamorous landing seems to have counted against them.

  23. aqk
    Coat

    Solar powered is just the first step!

    Gosh! Now that they've done (or almost done) a solar-powered aircraft, why don't they build a wind-powered one?

    I could see it now- two, or maybe four wind-turbines on the wings, and once those babies start spinning, ... we're off!

    Bet they could have one built by (say) next April 1st.

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