Hopefully not your every day solar blimp.

1. The temperature at an altitude of 20 kilometres is around minus 60° celsius (-76°Fahrenheit). This is chilly.

2. Stirling engines work on temperature differences.

3. Solar stirling engines are heated on one end by a dish which concentrates the sunlight and focuses it on one end, while the other end is cooled off by ambient temperatures [see link].

4. The temperature difference between high altitude and sealevel is around 80° celsius. Quite a bit which the stirling can take advantage of.

5. Build huge solar dish stirling from lightweight material. > put dish into a lightweight transparent plastic bulb, which is filled with helium, and acts as a lifting medium. > lift fuselage with electric engine powered by solar dish. > at night, store excess energy in hydrogen, or in a thermal battery or something like that.

6. At our altitude there are no clouds; you capture the sun from dawn to dusk.

7. It looks very strange. I made a drawing [see link].

Could be used for telecom-blimps and such.

Could be quite efficient maybe!
-- django, Feb 14 2006

Solar dish stirling http://www.stirling...astirlingengine.htm
Interesting concept, supposedly very efficient, one company which is building huge tens of square miles with this, claims efficiency of 26-30%, much better than ordinary solar panels. [django, Feb 14 2006]

Bizarre blimp drawing http://i3.photobuck...l/stirlingblimp.jpg
It looks spacey!! [django, Feb 14 2006]

Inflatable solar concentrator dish http://www.grc.nasa.../inflatable_srs.jpg
For deep space stirling applications. [django, Feb 15 2006]

Very creative. Have a bun.
-- MikeOxbig, Feb 14 2006


or two.
-- 2 fries shy of a happy meal, Feb 15 2006


Your form factor is stunning, though I suspect not one the engineers would settle on. The basic idea makes a great deal of sense though. [+]
-- wagster, Feb 15 2006


O Mein Gott! I have just found an ultra-light weight inflatable solar concentrator developed by NASA for a stirling dish engine in deep space. [see link]

In my blimp, we will fill this mirror with helium too, creating even more lift!!
-- django, Feb 15 2006


Utterly gorgeous illustration and good thinking utilising the temperature difference. [+]

If you can shape your envelope so that it inflates into a parabola or parabolic trough when at the desired altitude, you could line that with mylar and do away with the separate dish.
-- BunsenHoneydew, Jul 28 2006



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