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Old 06-02-2014, 09:58 AM   #11 (permalink)
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Originally Posted by Xist View Post
I read one novel where a guy floated using a sphere filled with vacuum. I am going to guess that it was powered by a tiny stable black hole.
The tinier they are, the more unstable they become, until *poof* it vanishes in a blast of raw heat and x-rays and, oddly, radiated gravity.

Ironically if you feed them on a regular basis, that tends to cool them down and they stabilize and remain docile. Kind of like having an edgy Doberman.

Physics is weird.

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Old 06-02-2014, 10:55 AM   #12 (permalink)
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Quote:
Originally Posted by Xist View Post
I read one novel where a guy floated using a sphere filled with vacuum. I am going to guess that it was powered by a tiny stable black hole.
Quote:
Originally Posted by elhigh View Post
The tinier they are, the more unstable they become, until *poof* it vanishes in a blast of raw heat and x-rays and, oddly, radiated gravity.

Ironically if you feed them on a regular basis, that tends to cool them down and they stabilize and remain docile. Kind of like having an edgy Doberman.

Physics is weird.
But, if you tie one (black hole) to a stick and hang it off the front of your airship....now that, is fast!
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Old 06-02-2014, 12:09 PM   #13 (permalink)
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All this talk about black holes goes right over my head. Aren't black holes an hypothetical construct offered by astronomers who can't or won't accept the implications of plasma physics on a galactic scale?

Anyway, Magdeburg hemispheres - Wikipedia, the free encyclopedia. Vacuum bubbles don't scale.

OTOH pure steam has approx. the same lift as helium. The Flying Kettle Project - balloons and airships filled with steam!

EDIT: Here. This is an icosahedral cage around a tensile bag, stretched to a 3.2 fineness ratio.



A more developed design would have a subdivided shell with a low-stressed, insulative skin. The inner skin would be highly tensed and made from some unobtanium that would have to be impervious to the corrosive effects of water on one side and the embrittlement effects of hydrogen on the other.

The upside is that instead of all the insulation being in a thin outer skin, the heat is inserted into the hydrogen in the inner bag and the steam become a layer of insulation as well. The steam would be at overpressure; so, worst case, the hydrogen might be at ambient pressure. Deeper vacuum = more lift.

Condensing the steam kills lift to facilitate ground handling. If it is designed to ever land.

Last edited by freebeard; 06-02-2014 at 01:34 PM..
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Old 06-02-2014, 06:11 PM   #14 (permalink)
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think

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Originally Posted by bobdbilder View Post
What do you think about this from Hybrid Air Vehicle UK. They brought back to UK a working unit that was supposed to see action in Afghanistan with the US military.

Isn't it a successful heavy-lift craft which can perform very efficiently with certain specific tasks?
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Old 06-02-2014, 06:14 PM   #15 (permalink)
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wind

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Originally Posted by Old Mechanic View Post
I always like the idea of an inflatable pedal powered aircraft. Using a lighter than air gas, for inflation, would reduce the effective weight of the plane-pilot combo, but it would probably not be practical in any wind conditions.

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I think Gallagher's attorneys would only allow him to pilot his White Dwarf on a tether.
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Old 06-02-2014, 06:34 PM   #16 (permalink)
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Quote:
Originally Posted by Xist View Post
The idea was that you could exceed the speed of sound without creating a sonic boom if you did not have wings and in order to fly,
Supersonic wingless aircraft do create sonic booms. When the V2's bombarded London in WW11, they produced a characteristic double boom. The first boom was the explosion of the missile when it hit the ground, the second heard boom was the sonic boom created by the missile when it entered the upper atmosphere which lagged behind the missile in reaching the ground. The V2 impacted at about Mach 2.
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Old 06-02-2014, 08:15 PM   #17 (permalink)
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I remember when it was tested here, even using an old US Navy blimp hanger. The Aeroscraft 'Dragon Dream', a new gen rigid aluminum-skinned airship prototype with compressed helium-bladder system that controls buoyancy and altitude. Lift off is augmented by turbofan engines and steerable rear props to move it forward. At speed, the aero shape is controlled by front canards and rear empennages. All fly-by-wire signals use fiber optics, immune to EMF interference and unaffected by lightning strikes. It even uses vacuum pods system to anchor it down without the need for an extensive landing crew.
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Old 06-02-2014, 10:06 PM   #18 (permalink)
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I really liked how they integrated "automatic" bouyancy compensation control for loading/unloading of cargo.
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Old 06-03-2014, 03:04 PM   #19 (permalink)
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Ouch, that footage is pretty badly damaged...

-soD
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Old 06-03-2014, 07:31 PM   #20 (permalink)
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'Dragon Dream' is seriously underpowered, and there are spots on the skin that had been overstressed and stretched already.

I believe the landing gear is hovercraft skirts. Using vacuum to anchor it wouldn't work until it is completely on the ground, if then.

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