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Bernoulli Balloon

Blow gas around and around; lift balloon with it.
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The Bernoulli balloon is a closed toroid; a donut. The walls are firm and inflexible. One or more strong fans are inside. The fan blows air such that it travels around and around inside the donut.

With the fan stopped, the BB interior is at atmospheric pressure. As the interior windspeed increases, the pressure exerted by the gas on the interior wall decreases. Under lower pressure, the airship now becomes relatively buoyant. At a fast enough internal airspeed it will become lighter than air and float. One can then gallivant around!

Benefits

1: Accidental holes in hull do not result in catastrophic loss of buoyancy.

2: No need for rare helium or risky hydrogen.

3: Whirling blades safely esconced within hull.

4: No good way to steer. There is not a drawbacks section, so this must go here.

5. Vertical take off and landing.

6: Whisper quiet!

bungston, Jul 10 2014

Bernoulli effect http://en.wikipedia...rnoulli's_principle
[bungston, Jul 10 2014]

[link]






       errrr
MaxwellBuchanan, Jul 10 2014
  

       Barely having read past the title (it's late, I'm off to that fluffy thing [Max] disapproves of) so I don't really no whereof I speak.   

       But, is this by any chance a hovercraft?
Skewed, Jul 10 2014
  

       Ah... no, I'm going to have to read this when I'm less cerebrally challenged.   

       I'll just echo [Max] & be off then.   

       errrr.
Skewed, Jul 10 2014
  

       Having actually tried something almost exactly like this (even to the toroid)...it don't work, sure you get a low pressure area, but then that just pulls on the surface of the baboon, or duct, or whatever the fan is bolted to..   

       The most impressive bit is the torque effect, where is spins on an axis and doesn't actually go anywhere....   

       But, if you unwind one of the Archimedes screws and glue it onto the outside of baleen, then it would generate some lift....
not_morrison_rm, Jul 10 2014
  

       Complaints relevant to a vacuum balloon apply here too, I am sure. Enclosing low pressure gas strains the shell which would tend to collapse inward.   

       But even if this thing did not float, would it weigh less when turned on? I am skeptical it would spin on an axis as not_morrison asserts - why would it. But an item which reduces its weight on flipping a switch would be great fodder for the Tesla society get togethers.
bungston, Jul 11 2014
  

       //One or more strong fans are inside.   

       One strong fan has a torque effect...trust me, I tried it.   

       //I am skeptical it would spin on an axis as not_morrison asserts   

       Skept as much you like...I'm easy.   

       You could theoretically have paired fans, counter- rotating, but the single fan experiment suggested that there's infinitely more torque effect than lift- effect, hence the idea to put an (do I have to keep typing this?) Archimedes screw* on the outside, then it might generate a bit of lift...   

       *Sounds like a cocktail for an engineer's bar**.   

       ** Assuming that engineers have their own bars, a bit like biker bars, but with a humorous left- handed thread on the bolt on the toilet door.
not_morrison_rm, Jul 11 2014
  

       //But an item which reduces its weight on flipping a switch would be great fodder for the Tesla society get togethers//   

       That would be a vacuum pump hooked up to a (initially air filled) vacuum tube wouldn't it.   

       This would be way cooler though, the void engineers would wet themselves.
Skewed, Jul 11 2014
  

       Can I just interject here?
pocmloc, Jul 11 2014
  

       I'm not sure if you're intentionally allowing air to flow between inside and outside or if the torus is normally sealed, but in either case, I'm pretty sure this won't work, even in theory.   

       The problem is that by circulating the air you reduce the pressure of the gas on the walls, but you don't actually reduce the mass. Pressure is being exerted in all directions, but there is less pressure on the top compared to the pressure on the bottom. When the overall pressure is reduced the difference in pressure between top and bottom is still the same because the mass of the gas is still the same.   

       Now if you get a hole in your torus, or you are intentionally allowing the pressure to equalize, some air will flow from outside to the inside, making it even heavier.
scad mientist, Jul 11 2014
  

       Hmm, it you were to try this, but using hydrogen instead of air...   

       Obviously the "lighter than air" hydrogen atoms would become even lighter so boosting the effect to being almost measurable level.
not_morrison_rm, Jul 11 2014
  

       /torque/ let us pair the fans /archimedes screw/ - I cannot picture it.   

       /Now if you get a hole in your torus, or you are intentionally allowing the pressure to equalize, some air will flow from outside to the inside, making it even heavier./   

       I see. You are in a complicated way pumping air into the torus. The closed torus, regardless of interior doings, has a fixed mass and volume and so cannot change its buoyancy.   

       /hangs head/
bungston, Jul 11 2014
  

       I took it for granted the torus was expandable.
FlyingToaster, Jul 11 2014
  

       Leaving aside all the impossilities as trivial, this thing would not be quiet. The sound of the fan, and the turbulent air---gaining turbulence as it turned in the torus---would transmit right through the walls. Or were they going to be very thick and sound-absorbing?
baconbrain, Jul 11 2014
  

       /hangs head/   

       Don't worry about it, at least you didn't spend like $40 on a model airplane ducted-fan motor, and spend two weeks faffing about with cardboard and duct tape...it kept me out of mischief for a while....   

       I thought, "if you don't try, you don't know" and always a few surprises out there in physical world, like x-rays from sticky tape etc
not_morrison_rm, Jul 11 2014
  

       // I'm adding [nmrm] to the list of people who should be expelled   

       Expelled from what, if that`s expelled from the law of thermodynamics, that could be handy...
not_morrison_rm, Jul 12 2014
  

       I think you need those to live.
rcarty, Jul 12 2014
  

       Why, what happens if he lets them die?
baconbrain, Jul 12 2014
  

       He wont be trusted with any more.
rcarty, Jul 12 2014
  

       Also consider centrifugal force increasing air pressure at the same time the Bernoulli effect is decreasing it.
sninctown, Jul 12 2014
  

       Jeez, now I'm Law of Thermodynamics monitor. Is there like a Scouting Proficiency badge for that?
not_morrison_rm, Jul 12 2014
  

       No but you should get a faffing badge. I now have this urge to faff.
bungston, Jul 12 2014
  
      
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