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Solar-Powered Ultralight To Try 24-Hour Flight

Posted by kdawson on from the mehr-licht dept.

blair1q writes "When the solar aircraft Solar Impulse lifts off from an airfield in Switzerland on a sunny day at the end of June, it will begin the first ever manned night flight on a plane propelled exclusively by power it collects from the sun. Former Swiss Air Force pilot Andre Borschberg and round-the-world balloonist Bertrand Piccard developed the aircraft, and Borschberg will be the pilot for this mission. 'The flight will require a lot of attention and concentration — the plane doesn't have an auto-pilot, it has to be flown for 24 hours straight.' For him, the most exciting part of the venture is 'being on the plane during the day and seeing the amount of energy increasing instead of decreasing as on a normal aircraft.'"

5 of 104 comments (clear)

  1. How about using thermals? by Anonymous Coward · · Score: 2, Interesting

    How about soaring and using ridge lift? Ridge lift has been long used by glider pilots for cross-country flights. This planes seems to be a good enough sailplane. I has large aspect ratio wings and lift to drag ratio is probably decent as well, even though it does not look very streamlined, but it the ratio of the lift to drag that matters and this thing has a lot of lift.

    Combined, solar and thermal energy (i.e. the energy of thermal air updraft) would yield a plane that could stay in the air forever.

    1. Re:How about using thermals? by Vihai · · Score: 2, Interesting

      You are so wrong here! Switzerland is fantastic for soaring, *especially* in summer.

  2. Oh god no by MichaelSmith · · Score: 4, Interesting

    I had a peek at TFA so I could comment. This thing would fall apart in a thermal. Ridge lift means flying fast to avoid flying into the rotor behind the hill. Its not uncommon to pull a couple of Gs flying into and out of a thermal and this aircraft doesn't look up to it to me.

    My guess is they are waiting for still air before they fly it. Look at the size of those control surfaces. Sure it will have a high LD but at 30 knots or so.

    --
    http://michaelsmith.id.au
    1. Re:Oh god no by Anonymous Coward · · Score: 1, Interesting

      Remeber that usually when entering a thermal one is flying at the McCready interthermal crusie speed, which accentuates the roughness of the sink at the edges of a thermal.(Which for the non glider pilots is like driving over cobble stones) This aircraft flying at minimum sink most of the time would not be disturbed as much.

      It would be interesting to know what the aircraft is stressed to. Normal sailplanes are around +5g -2.6g. I doubt this would be any less than +3g.

      Ac due to mods.

      Falconhell

  3. Manned missions are just ego-wanking... by Anonymous Coward · · Score: 2, Interesting

    Not that I mind a bit of ego-wanking.

    But human flight in this is limited by the pilot's endurance, so a theoretically indefinite duration is good for no more than 48 hours or so in practice.

    The same concept, but with remote/autonomous* control, yields really indefinite-loiter UAVs -- a much more practical creature.

    *Yes, I'm aware full autonomous control isn't feasible now, and begs for skynet jokes. But some automation for station-keeping without 100% human intervention is possible and highly desirable....