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Science Technology

Solar-Powered Plane to Fly Around the World 108

Posted by timothy from the adrian-monk-not-on-board dept.
securitas writes "The BBC's Carolyn Fry reports on the Solar Impulse project, a plan to circumnavigate the globe in a solar-powered airplane. Adventurers Brian Jones and Dr. Bertrand Piccard, who were the first people to circumnavigate the globe in a balloon in 1999, are behind the Solar Impulse project. The project is proceeding to the design stage after a feasability study determined that the solar-powered airplane concept is a viable idea. While other solar-powered planes like the Helios prototype have relied on a secondary power source (fuel cells), this project will be powered by solar energy alone. Batteries will store energy received in daylight hours to fly all night. The first prototype is scheduled for launch in 2006."
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Solar-Powered Plane to Fly Around the World More

Solar-Powered Plane to Fly Around the World

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  • What about... (Score:1, Interesting)

    by Film11 ( 736010 )
    Let me get this straight. Solar powered planes? How would this work in say a flight from London to America? It takes about a day in which the sun goes down. What will happen when the sun goes down? Will it crash? Will it run on reserve batteries? I'm not the world's most intelligent person, but I'm wondering how this will catch on...
    • During the day it would take some of the energy received from the sun and store it in the batteries. It would then use this energy at night.

    • Re:What about... (Score:1, Interesting)

      by Anonymous Coward
      And..
      is this to be a manned flight? All previous solar-powered flights were unmanned and remote-controlled, since the weight factor makes manned flight impractical, due to the small power available to a solar craft.

      • Re:What about... (Score:4, Informative)

        by rijrunner ( 263757 ) on Sunday December 28, 2003 @05:04PM (#7823610)
        No reason why it wouldn't be manned.

        They state a 60 meter wingspan. That would like be about 6 meters wide, if they keep a 10-1 ratio. The ground and sea also reflect a certain percentage of solar energy. Overall, it looks to me that the would have about 360m^2 of direct sunlight potential and about the same amount of reflected sunlight.

        The solar power is about 1.3kw/m^2. That is 460KW of direct energy. If they get a 30% reflection on the underside, that is another 140KW of potential energy. About 600KW total. Figure about 15% efficiency and you get about 90KW of power. That is about 120 HP, which is the same power as the rear engine of used on Voyager on it's round the world flight. Electric engines have an advantage here in that they don't lose power with altitude, so their effective engine power at altitude would be higher than that used on Voyager.
        Voyager only required two engines for take-off and to provide a secondary engine in case of problems with the first. The weight here will be constant throughout, so they will not need a second engine for take-off. (Voyager was basically a flying fuel tank on take-off and needed 300HP to take-off on it's runway. Once airborne, it only needed 110HP. Without all the fuel on board, 110HP was enough for take-off).

        Also, solar panel efficiency improves with a slight reduction in temperature, so they might manage better solar efficiency.

        Hmm. There is a dodge I wonder if they have considered. One of the problems with that they are doing is the weight. They have a background in ballooning. I wonder if they have considered incorporating sealed helium bladders in the wings and other areas that are not going to be occupied by people. If they can lower the effective density of the aircraft, then they will effectively lower it's weight. Not sure if it is worth the effort though. The other would be use open those sections to the air, then allow the heat from the solar panels heat the inner wings also effectively lowering the density of the aircraft, but this would not be as effective.

        • Re:What about... (Score:3, Informative)

          by mpe ( 36238 )
          No reason why it wouldn't be manned.

          Especially given that the pictures show what look like cockpit windows :)

          They state a 60 meter wingspan. That would like be about 6 meters wide, if they keep a 10-1 ratio. The ground and sea also reflect a certain percentage of solar energy. Overall, it looks to me that the would have about 360m^2 of direct sunlight potential and about the same amount of reflected sunlight.

          There is also the fuselage and the horizontal stabaliser.

          Voyager only required two engines f
        • "I wonder if they have considered incorporating sealed helium bladders in the wings and other areas that are not going to be occupied by people."

          Hmm I don't think its very simple to contain helium for a long period in anything other than a thick-walled metal cylinder. Doesn't helium just "leak through" most things within a few days/weeks, due to the very small atomic size? I know this is the problem with transporting/storing hydrogen, and I'd be surprised if this isn't the case with helium. Think abou

    • Re:What about... (Score:5, Funny)

      by Amiga Lover ( 708890 ) on Sunday December 28, 2003 @03:15PM (#7823067)
      Big spotlights on the ground shining up at the plane as it goes by!

      The spotlights will be powered by a combination of coal powered power stations in urban areas, ancient russian nuclear reactors... and furnaces powered by burning kittens.

      But the light is enviro friendly!

    • Batteries, you dummy (Score:3, Funny)

      by Anonymous Coward
      The solar cells will charge batteries. The batteries will power a bank of flashlights that will keep the wings illuminated at night.
    • Solar powered planes zig-zag their vector, gaining altitude and some distance in daylight hours but at sundown going directly to where sunrise will be, maximum warp (hey, the guy is called Picard!) but losing altitude. Repeat, repeat until destinaion.
    • I'm not the world's most intelligent person, but I'm wondering how this will catch on...

      Catch on? It doesn't need to catch on. This is not so much a product as a stunt. Think of Sir Richard Branson's balloon trip across the Atlantic.

      From TFA:
      The aim will be to deliberately use the project as a communication platform for the concept of renewable energy, and so generate public enthusiasm in favour of sustainable development.

      This is exactly the kind of thing you might do when you're rich and have more mo
    • What will happen when the sun goes down?
      Captain Picard will use the energy stored in the Dilithium crystals. ...

      Oh, wait, that's Dr. Piccard, not Captain Picard.
      Never mind.
  • How would it be to fly close to the pole that has summer. There the night is very short. And the distance is short.
    • Well, circumnavigation around the equator should be fairly easy to calculate since they get 12 hours of daylight pretty much the whole year around.

      Obviously the team will need to compensate for when it's going to be day or night, but this won't be hard. Though I doubt the thing will fly around the globe in 24 hours - most likely it'll have rechargable batteries for the nighttime.
    • Despite light through most of the 24 hours, the light is weak (i.e., not Saharan sun beams) so wouldn't be as much use as sunlight nearer the equator.
    • Because to fly around the earth completely, they would then have to fly across the Pole that is in winter on the next leg.. If you just go from equator to pole and pack you.ve only done half the trip.

      (The other issue that the the sun would slowly edge downward onto the horizon and would not be hitting the panels directly reducing the amount of energy available. The formula is actually rather brutal, but the main driver is the sine of the angle of incidence times 1.3KW/m^2).

  • What's the diff? (Score:4, Insightful)

    by blueberry(4*atan(1)) ( 621645 ) on Sunday December 28, 2003 @03:32PM (#7823158)
    While other solar-powered planes like the Helios prototype have relied on a secondary power source (fuel cells), this project will be powered by solar energy alone. Batteries will store energy received in daylight hours to fly all night.

    Helios used fuel cells to *store* energy from the solar cells in a closed system. This new project uses *batteries* to perform the same function. Therefore, the phrase this project will be powered by solar energy alone is not correct in implying there is anything significantly different than the Helios.

    (BTW, I did some minor work on the Helios fuel cells)

  • I hope they plan to do this in under 24 hours.

    • I hope they plan to do this in under 24 hours

      Actually, they have up to 36 hours in which to do it (assuming the flight happens on an equinox)

      Take off right at dawn, heading west. If you land at the same longitude as your departure point 36 hours later, you will land just as the sun is setting, and you will not have been in darkness at all.

      Of course, if you could increase power by 50%, then you could do it indefinitely, because the sun would not appear to move in the sky to you.

      Of course, since they ha
  • Aren't fuel cells batteries?

    • Re:fuel cells != batteries? (Score:4, Informative)

      by lommer ( 566164 ) on Sunday December 28, 2003 @04:39PM (#7823492)
      In one sense they are in that hydrogen is usually seen as an energy storage mechanism rather than a source (i.e. there aren't many natural sources of pure hydrogen). However, the relevance to this article is that the hydrogen fuel cells on helios were filled with hydrogen on the ground before takeoff, not filled with hydrogen during flight (presumably from electrolyzed water vapour, the electricity being provided by the solar cells). These batteries will be charged by the solar cells during flight.

  • Old News - Stuff that mattered (Score:3, Informative)

    by Dolphinzilla ( 199489 ) on Sunday December 28, 2003 @04:33PM (#7823455) Journal
    Back for a return engagement..

    Around the World in a Solar Plane [slashdot.org]

  • Piccards (Score:3, Informative)

    by pcraven ( 191172 ) <[moc.ylimafnevarc] [ta] [luap]> on Sunday December 28, 2003 @04:35PM (#7823472) Homepage
    The Piccards are well known for scientific exploration and adventure. Bertrand went around the world in the a balloon. The Piccard family is known as the inventor of the modern hot air balloon. Here [balloonlife.com] is info on Don Piccard, one of his relatives. The bathyscaphe used to explore deep ocean areas was developed by Auguste Piccard. I've had the pleasure of speaking with Don Piccard before. Great family all around.

    • Re:Piccards (Score:1, Funny)

      by Anonymous Coward

      Not to mention Jean-Luc, the famous starship captain.

    • Jean-Luc Picard, captain of the Enterprise was named after Jean Piccard, grand-uncle of Bertrand Piccard.

  • Old story! (Score:3, Funny)

    by rduke15 ( 721841 ) <(rduke15) (at) (gmail.com)> on Sunday December 28, 2003 @04:49PM (#7823543)
    This has already been discussed on /. [slashdot.org]

    But maybe I could get even better karma by reposting my old comments into this new thread?
  • ...that America and New Zealand don't refuse them use of their sunlight. Don't want to encourage these tourists after all.
  • ...storage. I know that the heavier a flywheel is, the more energy it can store, and the heavier an aircraft is, the more energy it takes to run it, so I'm not sure how well this really would work, though it has the advantage that it will take a long time to wear out. You might need multiple counterrotating flywheels or something, if you have two motors then you can put them in the same place as the motors. Batteries are annoying because they are toxic and wear out somewhat rapidly. In this situation it is
    • Way too heavy to carry on board and not really the right way to use a flywheel. They're great for providing short bursts of acceleration, but the constant drag on a propellor would stop a flywheel pretty quick. They're better in cars where weight is less of a problem and you can efficiently spin them up again with regenerative braking.

      However, you could definately power up a ground based flywheel from the plane's solar panels. It could then winch the plane up to takeoff speed and possibly the first few 100

  • just wondering... are there any electrical alternatives to jet engines that would provide similar speed? if we ever got entirely off fossil fuels, how would passenger jets work?
    • The best bet at this stage is liquid hydrogen. Airbus are already looking into it. [nwsource.com]

      It won't be completely clean though, there'll still be some nitrogen oxides (leading to acid rain) produced from combustion with the air. The other down side is they'll need bigger tanks because liquid hydrogen occupies significantly more volume than Kerosene, despite having greater power density.

  • I liked this part of the article:

    "The design incorporates a computerised body vest," explains Jones. "If there's stress on part of the wing, the pilot would feel pressure on one side of his body.

    "Equally, if the pilot is stressed the plane would sense this and only feed him must-know information."

    Sounds like something they should implement for wives.

    Oh, and this:

    Batteries will store energy received in daylight hours to fly all night.

    Then, batteries will store energy received in nightlight hour

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