h a l f b a k e r yMy hatstand runneth over
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I'm going to get bashed for this one, I'm sure, but I want to know if it's plausible.
It's not exactly a new idea as far as modern flight is concerned. It still relies on the same principles. I have no idea if this would work.
Resonate Nitrogen in the air over a wing. Resonating it should cause it
to gain energy and create a small column of slightly lower pressure air.
My understanding of this is so incomplete that I'm not sure of the physics. Would the air be less dense over the wing once the N expands from gaining energy, creating lower pressure on top of the wing than below?
If so, how powerful would the lift force be? Even if it is weak, it could still have advantages. It could be used to create a "tunnel" of less dense air for cars, thus increasing MPG by reducing drag.
Already sonic devices are available that can be highly unidirectional, likened to lasers.
+See Link+
Sonic "Laser"
http://www.wired.co.../news/2005/09/68732
To further complete my humiliation with a link [Holeinmysock, Aug 15 2007]
MAD
http://www.getmad.com/index.html
I want to get MAD! [Ling, Aug 16 2007]
[link]
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Could you elaborate on the mechanism of "resonating N"? Are you referring to the nitrogen content of the atmosphere to somehow be selectively afflicted, or do you propose to release nitrogen above the wing constantly, or somehow by "resonating" it keep it there? |
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There is a way to reduce drag / improve stalling behaviour by vibrating the wings by means of piezo-thingies (can't find link). |
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Specifically, I was referring to the N content in the air. Could you keep the N over the wing? That would create a sort of lighter than air balloon. |
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Oh, and I chose N, because from what I can remember the air is mostly N. |
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If you could somehow repel N2 above the wing, wouldn't the repulsion field (whatever it is) force the wing down by exactly the same amount? IE, for ever action a reaction. |
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I think this could be the basis for a truly genius idea. |
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But - I don't think we need bother about fiddling about with different gasses. |
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If instead, we can cause a layer of air, just above (or below) the wing to resonate, changing its overall pressure relative to its surroundings(need to check into pressure changes within resonating gasses) then we might be able to get some lift. |
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I've heard of a machine (it looks like a great big tv aerial) that ionises the air above it, and gains lift from that - it may be possible to drop/raise the density of air above/below some device using 'resonation' of some sort. |
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[ldischler] if the air could be spread out sideways over and beyond a wing, that could create a flow that might generate some lift. |
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Zen, I've seen those! Type "Lifter" in google.video to see a miniature lifter in action. How would the amount of surface area of the wing affect the lift with an airflow that spread like that? More surface area=more lift? |
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Don't know - I'm thinking of a narrow band of noise either just above, or just below a 'wing'. |
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It depends on whether resonating air spreads out, or bunches up. (Or both, and stays the same) |
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If you had a disk shaped surface, with a layer of air that was rapidly expelled over its top surface off to the sides, there should be an overall lift. |
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If you got clever, and started spinning the disk, or somehow encouraged the air above to arrive at the disk at an angle (sort of tornadoish) you might be able to increase the overall airflow, and in doing so, get more lift. |
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Since rapid upward motion of such a disk will create a region of low pressure air beneath it, there will be a proportion of drag that's proportional to the size of the wing - so no more surface area doesn't necessarily mean more lift - there's probably some set of curves, each with an optimal surface area for a given speed. |
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But - the real part is figuring out a way to expel all that air... |
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I believe bumblebees and some other insects use the resonance of air to create standing waves to assist their flight. |
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Using a charged fusilage to ionize the passing air has been proposed for a hypersonic ramjet aircraft mainly to reduce friction but also to add a patheticaly small amount of thrust. |
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Wow, all very interesting. I particularly like the stereotypical 'spinning disk' design. Maybe in combination with the Ion thrust, the spinning, and the resonating air, there would be sufficient lift.
To address the drag problem, the wing could be teardrop shaped. Scratch that, mount the TearDrop Ion Turbines (TIT)s on planes in place of the rotors or jet engine...or heli/gyrocopters. |
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1: Obtain powerful amplifier; hook to tuning instrument that can generate pure tones.
2: Obtain precise scale.
3: Place amp atop scale, facing up.
4: Weigh. Turn on amp at max volume; weigh again.
5: Slowly change frequency over the range of the amp. Chart weight of amp. |
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If this idea has merit, there should be specific tones at which the amp is measurably lighter: the reduced density of the resonating air column above the amp should increase the buoyance of the amplifier at the bottom of that column and decrease its measured weight. This could be charted as a graph: amplifier weight vs frequency. |
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As [zentom] observes, I am not clear on whether a resonating air column would be more or less dense. I suspect less dense as the particles would be farther apart. Resonating sand is less dense. If less dense, this device should be mounted atop the wing, not below. Either way, this setup as described should be able to measure effect. |
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This could even be done with common lab equipment and the superprecise scales available in many labs. A smaller amplifier would produce less measurable effect, but smaller amps would fit more easily on a precise scale. |
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This would be a first rate high school science experiment. |
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I think the title of this idea should be changed to "flight via resonance" to facilitate its discovery by people interested in such things. |
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I thought of another, possibly easier way to demonstrate this. Obtain a large helium balloon. Attach weights to the string such that it is neutrally buoyant. Get amp and tuning instrument as described above and aim amp at balloon. If the gas in balloon can change volume by virtue of resonance, you should be able to make the balloon rise or fall by changing the tone projected at it with the amp. Increase in volume will make the balloon rise, because the weight remains the same. Viceversa for decreased volume (I think that volume decrease on resonanting is unlikely). This would be visually more exciting than the graph of amplifier weight. Larger balloons would work better because more gas would resonate, magnifying the effect. |
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The N thing is a red herring. Air will be fine. |
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Vibrating air will have different pressures throughout the wavelength, so the principle is to push against the wave as it has high pressure, then pull away from the low pressure half. |
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To resonate an air column, doesn't it need a couple of nodes? One way to do this is to have a 'wing' with 90 degree upturned wing tips, and resonate the air between the wing tips. |
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Since air pressure reduces as velocity increases, I cannot see why it shouldn't produce a lower pressure when resonating, as resonating air is obviously moving. The difference, of course, is that the wave travelling speed is not the same as the air particle speed, as a whole (some particles must travel at the speed of the wave, but most will not). |
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the wavelengths of sound/pressure-waves are way too large to resonate individual molecules in the air, but you could use it to resonate the whole air.... you need to use photons (oscilating energy packets of em-radiation) to resonate individual molecules, whereas a sound wave can be thought of as millions of molecules in the air being pushed back and forth in a dominoe effect! Or to put it differently, the resonant/absorptive wavelength of N2 in the air (337 nanometers) is much smaller than the mean free path of the air itself (0.1 micrometers at STP). |
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one could possibly set up ones resonator so the the top of the wing or craft (may not need wings) caught the low pressure part of the wave whilst the bottom got the high pressure part. |
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The concept is interesting. I doubt that a single resonating device will work on top or bottom of the "wing". Think about a resonator alternatly compressing and then not compressing the air above a liftable object. Although there are times when the air is less dense the effect is offset by the times the air is more. We have all seen footage of the old "flying" contraptions that never really worked. Remembering one I saw that had a rather silly lloking umbrella device that violently oscillated up and down in the attempt to "fly". The thing did get off the ground, on many occassions...only about five inches and then was violently slamming the carriabe back onto the surface as it oscillated. I think a sonic device would do the same on a smaller scale. However, I wonder about placing one on top and one on bottom and tune them to be exactly out of phase 180 degrees...the top one expands, as the bottom compresses...heavy on the bottom and light on top...would air thrust be a factor offsetting the effect? |
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One could only prove the concept by experimentation. I think it is well worth a small initial investigation, as many have suggested here. |
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Hmmm. Were trying to construct a standing wave then move by remaining in the low pressure portion of the wave. Wouldn't this optimum zone always be a certain distance away from the source of the occilaiton? We have to move an equivalent mass of air to acieve lift..... Nope not happening not even on a tiny scale unless the sound is coming from some external source (baked). |
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Holding nitrogen above the wing, by whatever method, will
just make that nitrogen effectively part of the wing. This
will just result in a taller wing, not an enhanced low-
pressure region. Also, even if it somehow could, nitrogen
doesn't magically have lower pressure than the surrounding
air, just lower density. Gases equalize. |
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(This could be useful for other purposes, though, to be able
to adjust the thickness of your wing in flight.) |
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