# Sonic Levitation for aircraft?



## Creator (Jan 3, 2008)

I wonder if sonic Levitation can be utilised for lifting objects and I know the problem is that it cannot work in space but we have an atmosphere so..... it shouldn't be too much of a prob right?


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## chrispenycate (Jan 4, 2008)

Problems you are going to have, if for no other reason than that acoustic energy in that sort of quantity is very destructive, and difficult to direct effectively. Big outdoor PA systems are producing a few tens of acoustic watts - convert this to horsepower, and try to imagine how loud a manned vehicle would have to be. Such a craft would, however, be quite an effective weapon, pulping flesh or airquaking down buildings depending on frequency.
I've never heard of sonic augmentation being used on anything larger than a bumble bee, but that doesn't necessarily mean it couldn't work, preferably at very low altitudes, where the energy can reflect back off the ground...


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## PTeppic (Jan 5, 2008)

THough I have no sources, isn't there a group of scientists, researchers or er, loonies, who think that the ancient Egyptians had some very advanced sonic technology for moving the multi-tonne stone blocks when building the pyramids?


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## Delvo (Jan 5, 2008)

I don't understand what made you think of this idea. The sound source doesn't move; it sits below and levitates a very tiny thing above it. Even ignoring size-scaling effects, as soon as the levitated object moves laterally, it's no longer above the thing that it needs to be above in order to levitate, so it falls. What application did you have in mind for this? Outdoor open-air elevators? Ground vehicles that carry along a levitating object above them wherever they go? Roads that make sound so the vehicles levitate above them and glide along the line? Vehicles that are launched vertically and fly on their own power or glide after that?


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## Nik (Jan 6, 2008)

*Rofl...*

IMHO, sonic levitation of anything more massive than a fly needs energy densities that would indeed cook and/or deafen the bystanders.

Ever stood in front of a pop concert's speakers ?? Or beside an un-muffled jack-hammer ?? And a jet engine's noise is just part of the waste...

Principle works well in fluids, think of sonic cleaners bouncing dirt out of cracks. And, yes, revealing dye in faulty welds etc. But remember some cetaceans are suspected of using sonic pulses to stun their prey...

Um, nearer the ground, ultrasound can be used to break static friction. A lot of micro-machines use 'inchworm' piezo actuators.

Principle works on a macro scale, too. Most people have, at some time, had to thump a balky piece of machinery to break the 'stiction'. Engineers keep a 'soft faced hammer' for the purpose...

D'uh, the work-benches in our lab were variable height, their legs *massively* constructed of welded steel tube and thick lead-screws. After a few weeks, they'd settle their feet into the floor by a whisker's depth, be almost impossible to shift...

And, yes, their weight required *three* people to re-position. Unless you very carefully chose your angle and tugged skew, causing the frame to flex slightly, and the legs to walk, where-upon you could hurry the massive beast across the room like an iron donkey or steam-punk 'bot...


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## chrispenycate (Jan 6, 2008)

Oh, lifting something half a millimeter or so, sufficient to break it free from ground friction on a smooth floor, quite conceivable; I've had a hundred and twenty kilo bass stack wander round the stage looking for the lowest point. But most sound waveforms are symmetrical, which means that it's only lifted half the cycle. To get true levitation, you need to work with shock waves, which, although at first sight resemble audio waves, travel at higher speeds and are much less linear. These tend to break things, and pulverise concrete, and suchlike inconveniences (yes, ultra high-power sound, foghorns and sonic cutters, has been part of my work environment, and rock and roll PAs a much larger part)
I see air cushion as a much more genteel technique, if you can find a way to inject air under the object.
Yes, I am getting old - once upon a time I'd have tried to combine the two, using the vibratory energy to provide a space to pump compressed air into, speeding it in with shaped shockwaves.
Oh, and the technique could work in vacuum, using structure-borne vibrations.


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## Nik (Jan 10, 2008)

*Trumpet Heat Pump...*

Um, IIRC, some-one spotted how to build a pump-less heat-pump by using standing waves in a convoluted, but sealed container. Neat, because there's only a piezo horn-driver. No fancy plumbing and fancier seals, no motors, heaters or toxic/green-house gasses, no fragile and expensive Peltier devices etc. Acceleration and radiation tolerant, attitude independent, the tube may be a support element, the driver circuit's trannies may be attached near the cool end for 'bootstrapping'...

Snag is the 'loudness' inside the tube is similar to the RF density in a microwave's klystron, and as dangerous if leaked...


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## RJM Corbet (May 19, 2011)

chrispenycate said:


> Problems you are going to have, if for no other reason than that acoustic energy in that sort of quantity is very destructive, and difficult to direct effectively. Big outdoor PA systems are producing a few tens of acoustic watts - convert this to horsepower, and try to imagine how loud a manned vehicle would have to be. Such a craft would, however, be quite an effective weapon, pulping flesh or airquaking down buildings depending on frequency.
> I've never heard of sonic augmentation being used on anything larger than a bumble bee, but that doesn't necessarily mean it couldn't work, preferably at very low altitudes, where the energy can reflect back off the ground...



They tested that 'sonic weapon' thing on Mythbusters. With headphones, etc. It was 'busted. I imagine It may work in water though ...


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## Metryq (May 20, 2011)

*Re: Trumpet Heat Pump...*



Nik said:


> Um, IIRC, some-one spotted how to build a pump-less heat-pump by using standing waves in a convoluted, but sealed container.



Sounds like Belldandy's Maxwell's Demon propelled aerial broom in the manga _Oh, My Goddess!_ (Chapter 21 Volume 3). The Maxwell's Demon stone turns the broom into a kind of ramjet.

One of the things I love about the series is the constant mixing of science and fantasy.


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## kono (Jul 24, 2011)

The only way for feasible acoustic levitation aircraft is to use a non destructive frequency. This technology obviously doesn't exist yet. All I know is that the flight technology that we use today is dated technology and we've basically reached it's limits. The same can be said for the cars we drive day in and day out. 

Acoustic levitation was arguable used in ancient times for lifting tones as big as 1000 tons. Even with today's technology that type of lift would prove to be very challenging. So how did these primitive civilization move such stones? Acoustic levitation?


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## Nik (Jul 24, 2011)

Lots of strong men, Kono, with strong ropes, big timber levers and a LOT of attitude. IIRC, there were 'masons marks' showing the movers worked in teams. Archaeology showed they were fuelled by bread and beer, in quantity. Now think 'American football teams', and how much rivalry squads show...


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## Dave (Aug 5, 2011)

chrispenycate said:


> Such a craft would, however, be quite an effective weapon, pulping flesh or airquaking down buildings depending on frequency.


Didn't Douglas Adams have that idea with the Plutonium Rock band Disaster Zone?


> generally held to be not only the loudest rock band in the Galaxy, but in fact the loudest noise of any kind at all. Regular concert goers judge that the best sound balance is usually to be heard from within large concrete bunkers some thirty-seven miles from the stage, while the musicians themselves play their instruments by remote control from within a heavily insulated spaceship which stays in orbit around the planet – or more frequently around a completely different planet. Their songs are on the whole very simple and mostly follow the familiar theme of boy-being meets girl-being beneath a silvery moon, which then explodes for no adequately explored reason. Many worlds have now banned their act altogether, sometimes for artistic reasons, but most commonly because the band’s public address system contravenes local strategic arms limitations treaties.


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