h a l f b a k e r y"My only concern is that it wouldn't work, which I see as a problem."
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Create a solar blimp that uses the power of the sun to heat the air and make it float.
This is not a new idea. However what if you also include a RC box to the bottom, and use it to control the blimp via small solar panels.
If you include a small air pump to the blimp, you can also easily replace
loss of air.
This shall allow you to create an autonomous or RC blimp without needing to fill it with helium.
Solar balloons. dot com.
http://www.solar-balloons.com/howto.html [afinehowdoyoudo, Feb 16 2011]
[link]
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I am surprised that no one has done this yet. May I suggest Vehicle: aircraft: airship: solar as a category? |
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//This shall allow you to create an autonomous or RC blimp without needing to fill it with helium.// |
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But it will have to come back down to the ground every night while designs which use a burner or hydrogen/helium can stay aloft for weeks or longer. |
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It will also have to be bigger for a given amount of lift and will thus encounter more drag. Which means it may require more energy to travel than H/He/burner designs even if it can ascend for zero energy. |
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Ah, but could a solar balloon collect enough solar radiation during the day, while above cloud cover, to focus an uv light through an underside aperature overnight long enough to keep it aloft until morning? I'd think it would be down to a size/lift/weight ratio thing. |
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Perhaps it could be a double bagged sort of thing? One transparent outer skin, and a black inner balloon. |
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That way you reduce heat loss. |
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I like this, and am also surprised it's not been done. I am
pretty sure that, with a decent-sized blimp, you would be
able to harvest more than enough energy by day to keep it
aloft by night. The whole thing would need to be fairly large
(since efficiencies of blimps increase with size, and
particularly so when they have to carry hardware). |
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//with a decent-sized blimp, you would be able to harvest more than enough energy by day to keep it aloft by night// |
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By decent sized, I assume you mean an enormous ocean liner sized thing that costs hundreds of millions and therefore gives no real advantage to radio control over a blimp with a pilot. |
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//no real advantage to radio control over a blimp with a
pilot// It might be a real advantage for a robotic probe
exploring a planet with 1) an atmosphere 2) not too much
cloud cover 3) sufficient sunlight. Mars, maybe. |
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What (you ask) would be the advantage over an orbiter?
Maybe the ability to parachute robotic land rovers more
gently (and perhaps with greater precision) onto selected
terrain features than an orbiter could do. |
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// assume you mean an enormous ocean liner sized thing
// |
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Au contraire. I suspect that something the size of a bus
would do the trick. It would have an insolation of about
50kW in daylight, of which perhaps half could be captured
as heat, or 12kW recoverable averaged over a 24hr period. |
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Given a double-skin envelope, this is amount of energy
should be way more than is needed to keep the balloon
aloft with a payload of a few kilos. The payload needs to
include the radio control and propulsion, and also a means
of storing sufficient heat to see it through the night
against losses. One option would be some phase-
transitioning liquid/solid, but it might be more effective
to use a smallish heatpump to store hotness more
densely. |
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Another option *might* be to line the bottom-inside of the
balloon with photovoltaics. These would generate enough
electrical power to be storable for overnight heating (but,
at considerable and perhaps unreasonable weight cost),
but they are sufficiently inefficient that most of the
insolation would still warm the balloon during the day. |
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The best overnight energy store might simply be hot air, if you don't mind wild fluctuations in lift and therefore altitude. It could slowly descend during the latter part of the night, as long as the sun comes up before it touches down. Extra energy is stored during the day as altitude, and the duration it needs to maintain positive buoyancy is reduced. |
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Do you need the air pump? Doesn't a solar balloon self-inflate, like a conventional hot air balloon, if it has a small opening at its lowest point? |
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I thought at first that this was something you took out and flew during the day, then packed away. The requirement to stay aloft during the night adds a whole extra difficulty level! |
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Ah, yes. Just what we need. A night sky full of Bladerunner-esque, advertising blimps. No thank'ee! |
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