Can Orthosonic Lift Challenge Traditional Theories of Flight?

[Faradave]

As I have been banned 3 times from PF for "continued promotion of personal theory", I am hesitant to begin this thread which, as far as I know, is entirely personal theory. So, let me start with a disclaimer. I am not an engineer, just an amateur experimenter, fascinated by physics. All of the experiments I describe are my own and I may be misinterpreting the results. Help with interpretation is actually a large part of why I am here. These experiments are relatively simple and great fun to try yourself at home with reasonable precaution (i.e. earplugs). I’ve safely done hundreds of them.

I will break my posts into a logical progression but to summarize, I am able to generate aerodynamic lift using a flat wing, zero angle of attack and zero net airflow with quite small amounts of energy. In some experiments, I believe I have eliminated any opportunity for downward air displacement and yet still have lift. Though I will need to reveal a snag on the way to flying cars, this should still contribute meaningfully to the discussion of Bernoulli vs. Newton as the primary cause of lift.

In May Frank Kecskes had an interesting thread suggesting vibrating airfoils (https://www.physicsforums.com/showthread.php?t=403729), which reminded me that I had tried this back in 1972 and quickly burned out my inadequate solenoids. Over time, I switched strategies to vibrating the air instead of the wings. Since Bernoulli’s equation gives change in pressure proportional to difference in squared velocity it seems that root mean squared (RMS) velocity ought to apply as well as constant flow. This is analogous to the idea that an electric resistor will dissipate power from direct current (DC) as well as RMS alternating current (AC). I only began photographing my experiments in 2006 so those are what I will refer to here.

Using a cut 2 liter soda bottle mounted horizontally on a wood frame, I constructed a Bernoulli wind tunnel. I taped a paper strip to the opening of the bottle as a lift indicator. Later I added a curved piece of plastic tubing containing some colored water as a barometer comparing pressure in the narrow neck of the bottle to the wide part. For DC airflow, I used exhaust from a shop vac clamped in a wood plate to the back of the bottle (a hair dryer also works).

 

[Faradave]

You can see the paper strip elevate nicely (with attendant pressure drop - fluid rise) in the attached photos.

 

[Faradave]

For low frequency, AC airflow, I used a Polk Audio, 50 watt woofer driven by a sine wave generator and audio amplifier. I also connected a frequency counter (since the wave generator, made from a kit, is only approximate) and an audio power meter. At 75Hz, I show a lift sequence increasing from 0 to 15 watts RMS (see photos). If you want to try this and don’t have a good woofer handy, take a walk around your neighborhood on trash night. Many folks upgrade their TV/computers and toss out old subwoofers. Decent function generators are available for around $40 from Elenco (Amazon has them). Audio system amplifiers and many home theater systems have an Aux. input which can be used for amplification (but don’t use the family’s main unit, in case you burn it out.)

 

[Faradave]

Something you won’t see with DC flow is lifting double strips (as shown here), one inside and one outside the bottle (30Hz at 0.0 and 0.5 watts RMS). DC tends to blow the inner strip right out of the bottle.

 

[Faradave]

Extending the concept to airfoils, I show a balsa wood model (mass=1.3 grams, chord=2.5cm, camber=0.5cm, span=3.1cm) suspended by threads in a 10cm long plastic tube between two woofers mounted on faceplates with circular openings (4cm diameter). The woofers are wired antiparallel so that the diaphragms move in unison producing a sonic wind (54-55Hz) across the airfoil (you can visually verify this at 1-2Hz).

When the airfoil was mounted upside down (by rotating the tube), downward lift was noted as straining of the threads. No lift occurred if the speakers were wired in parallel, simply compressing and decompressing the air without appreciable RMS flow. The plastic tube can be made by cutting the ends off a plastic spice (or small shampoo) bottle. You could also cut a rectangle from a soda bottle and tape two opposite edges together. An airfoil can be made from two unequal lengths of index card. Pre-curve the longer one and tape across the leading and trailing edges to the shorter one. Tape threads to the lower outer corners. The free ends can be inserted into slits cut in the circular ends of the plastic tube where you can also adjust the airfoil’s position nicely. [more later]

 

[Faradave]

I use the plastic tube to concentrate sound energy and keep the noise down a bit at audible frequencies. Some might feel the tube creates eddy currents (acoustic streaming) which lift the airfoil instead of by orthosonic lift (Bernoulli principle using RMS velocity). I believe inverting the airfoil answers this, but I also repeated the experiment in open air (25 watts per channel, use hearing protection!). I looped the airfoil’s threads around tacks in the speaker orifices and taped the ends to the edges of the faceplates. Note: the power meter reading (and LEDs) in the background corresponds to airfoil lift.

Inverting the airfoil again resulted in downward lift.

 

[Faradave]

Replacing the airfoil with a flat piece (cut from a playing card) with the same base dimensions resulted in no lift (seen vibrating below the frequency display in 2nd thumbnail). In a later post I will get around this by limiting sonic flow to the upper surface, an important advantage for orthosonic lift.

 

[Faradave]

I never would have guessed it by observing the steam gently wafting from my morning coffee, but if contained while energy is added, we all know now that steam can be made to move a 600 ton locomotive! Standing wave patterns partially contain sound energy.

For low frequencies, I made a folded horn from PVC pipe with a removable center section where I could mount an airfoil. In this case, the horn is 3.39m long with woofers (displacement antinodes) at both ends wired in parallel. At about 104Hz and 198Hz standing waves occurred with a displacement antinode at the airfoil. Lift was observed tightly (±7Hz) about those resonances. Changing the polarity (180° phase shift) of one of the woofers, gave different resonances. Replacing the airfoil with a flat card of the same base dimensions resulted in no lift.

 

[mugaliens]

I can't say why you were banned, but nothing you've posted herein violates any laws of physics from I can ascertain on a quick run-through, and given your verbag, it appears you're fairly familiar with acoustics.

I'll need a more definative go at it in the morning, and it would be nice if you could provide some math supporting your experiments. I do observe, however, that you claim not to be a math or engineering guy, just a tinkerer, and that's something I hope the rest of us keep in mind as we approach your presentation, refrain from "show me the math!"-isms, and hopefully, with the goal of using your descriptions and video to help us explain the physics behnd your observations.

If I were you, however, I'd refrain from using the term, "orthosonic lift," as it's found absolutely nowhere else in literature other than your posts here on Physics Forums. The prefix, "ortho-" refers to either an insecticide company, or simply, from Greek's "orthos," meaning "straight, right, or true." On the other hand, if what you're talking about is a way of using standing waves to generate lift, you might actually be on the correct track, terminologically speaking.

 

[Faradave]

Thanks for your comments. My infractions had nothing to do with classical physics. I asserted that a reference frame moving at lightspeed might be viewed as a relativistic inertial reference frame. That is considered not only wrong, but forbidden discussion at PF. Pity. Boundary conditions often are the most interesting to discuss and explore.

At any rate, I should be clear that in the experiments I am describing here, the only math I recall relates to estimating expected harmonic frequencies. I use v = λf, where v is the speed of sound, λ is wavelength and f is frequency. I figure v = 331.67 + 0.607(T), where v is in meters/second in air and T is air temperature in °C. My basement lab is usually about 21°C so v is typically 344.4m/sec.

For the folded horn above (post #8), path length is given as 3.39 meters. That's from the outside faceplate of one woofer to the outside of other, using the center of the PVC pipe as the path (including around corners). In addition, the faceplates are 1.8cm thick and the woofers have a cone depth of 3.3cm each. I did not monitor the temperature inside the tube, which I imagine could warm with prolonged acoustic stimulation. So estimates are a bit shaky but the horn would seem to be about 1λ long at 100Hz and 2λ at 200Hz. Also, despite hearing protection, there seemed an increase in perceived loudness, indicating harmonics near these frequencies.

I coined the term "orthosonic lift" specifically to distinguish this effect from "acoustic levitation". The former is intended to describe a drop in pressure directed inward, perpendicular (orthogonal) to the particle displacements, which for longitudinal waves is in the direction of propagation. Acoustic levitation, as you know, tends instead to sweep particles to displacement nodes, with pressures in line with sound propagation.

 

[Faradave]

I mentioned in post #1 that I had achieved lift with no camber, angle of attack nor net airflow. This experiment will do that while reminding you of a "trick" you may remember from youth. In the trick, you take a 2 inch square cut from an index card and push a thumbtack through the center. Then you hold the card so the tack point rests in one end of a hole below a spool of thread while you blow gently downward through the other end. Slowly remove your hand and, as if by magic, the card and tack stay levitating near the bottom of the spool as long as your breath lasts.

I consider that a pretty good introduction to lift as a result of the Bernoulli principle. Your radially deflected breath has a velocity and an associated drop in pressure which upholds the card despite gravity and the small area under the hole where your breath has a positive downward pressure.

The same effect can be accomplished dramatically with orthosonic lift involving radial deflection. I mounted a woofer to a wood faceplate with a 1 inch central hole, nicely beveled around the inside and outside edges. This was mounted face down 4.5mm above a solid board taped to a lab scale. At 55Hz, I gradually applied power (RMS) to the woofer. Lift was measured as decreasing grams from the board on the scale. Here’s what I got.

watts : grams lifted
0.0 : 0.0
0.5 : 1.5
1.0 : 3.6
2.0 : 11.2
2.5 : 17.5
5.0 : 28.6
10.0 : 51.3
20.0 : 64.2
30.0 : 73.0
40.0 : 80.4

Above 40 watts the 75g board and metal scale pan were sucked right up off the scale base! With a narrower gap between the speaker faceplate and the lower board, the effect was markedly increased. For example at 55Hz and only 5 watts, a 2.1mm gap lifted 52.2 grams, almost twice that achieved at 4.5mm!

 

[Faradave]

To lift a non-airfoil, I cut a 2 x 2 x 1.25 inch (1.8 gram) Styrofoam brick. This was slid between two woofer faceplates (1.5 inch apart) with the floor, roof and back wall blocked off. The woofers were wired antiparallel to have their facing cones move left and right in unison.

At 40-45Hz and 2-4watts RMS/channel the Styrofoam lifted well between the open ports. (4watts for lift off, 1watt to cruise). Both lift across the flat top and bilateral radial deflection may have contributed to the rise but either way, this "flying brick" is courtesy of orthosonic lift. In addition, if a torn out magazine page is held in front of the opening between faceplates, it is readily sucked in when power is on.

 

[Faradave]

I wanted to quantify flat wing, zero angle of attack orthosonic lift. The woofer faceplates with circular ports were replaced with faceplates having horizontal oval ports. Between these, on the scale, a small wooden sled was placed. The sled consisted of a 8.0 x 2.25 x 0.75 inch plank with thin (popsicle stick) sidewalls attached to contain sonic flow from the oval ports along its length. The sled had a mass of 109.7 grams when taped to the scale pan. With sonic flow above the plank (65Hz, RMS watts/channel), orthosonic lift was apparent as a reduction in apparent mass as shown.

watts : grams lost (upward orthosonic lift)
0.0 : 0.0
1.0 : 1.1
5.0 : 5.4
10.0 : 7.3

 

[Faradave]

As the side walls of the sled (post #13) extends above the plank to a larger degree than below, it could be inverted channel sonic flow below the plank. In this mode (65Hz, RMS watts/channel) the sled's apparent mass increased (downward orthosonic lift) as shown.

watts : grams gained (from downward force)
0.0 : 0.0
1.0 : 1.8
5.0 : 7.7
10.0 : 8.2

A similar wood plank without sidewalls revealed orthosonic lift as apparent changes in mass about 30% lower the sled. Removing the scale and with the woofers running, I could easily feel inward orthosonic pull as I repeatedly passed a wood paint stirrer through the sonic flow.

 

[JaredJames]

Hi Faradave,

I've been watching this thread from the beginning and seeing as no one else (mugs aside) has responded I'm going to give it a go.

Firstly, I think given the nature of your experiments this thread would have been better suited to the Aerospace forum.

Secondly, I don't think it is entirely clear here what you want from people (I may have missed something). Perhaps if you outlined clearly what you want people to do for you they would know what you were after. Again, aerospace may have given you a wider and more knowledgeable audience given the nature of the experiments.

Finally, I agree with mugs that you acknowledge you are not an engineer and don't really know the maths so I will refrain from the "show me numbers" attitude, however I think it would be good if you could at least give us some background materials (if they exist).

I find this a rather interesting set of experiments and would hope eventually someone will be able to give you the answers you are looking for. I, as it stands right now have no idea what I am looking at without much deeper study and so my advice is limited.

Jared

 

[Faradave]

Thanks for the reply Jared. I agree that I am probably in the wrong place. I put my thread here because that’s where I found Mr. Kecskes’ thread on vibrating airfoils (post #1) when searching to see if anyone else had developed this idea. I will take your advice and create a new thread, Orthosonic Lift (high frequency) addressing my explorations of that aspect in the Aerospace forum. I don’t know how to move this thread there, so I will include a link back here for this low frequency consideration.

I haven’t said what help I would like yet. I’ve become shy, because I just got back from 3-month’s exile and I still have loads of physics to discuss. If I am banned again, it could be permanent. Each day I go without an infraction I feel a little more confident, so that's a help in itself.

More specific to this thread, I am helped by the fact that no-one has so far said, "That’s impossible!" or "That’s Ridiculous." In 1983, I had a paid consultation with a physics professor to discuss some of my early work with orthosonic lift. He dismissed the idea as hopeless, because the particle displacements are very small and sound energy is too weak. He refused to even look at a short videotape of my experiments and referred me to microscopic photos of backlit smoke particles resonating in a Kundt’s tube (aka "K-tube"), designed to demonstrate standing sound waves.

Sonic particle displacements are indeed small, especially at ultrasonic frequencies. But my loose interpretation of Bernoulli’s Equation is that Lift is proportional to Δ(V²) where V is particle velocity (perpendicular to lift). The first thing I see is that V² allows +V, -V or both as V_rms. The next thing I see is no minimum time or space over which lift develops. Bernoulli pressure appears to have instantaneous values at every point along a flow.

So it’s amazing to me in a world where electricity has found huge applications in both AC and DC realms, how can it be that in aerodynamics there is so little to do with AC flow. Geez! Electric "current" is named by virtue of its analogy to current in fluids. We have to be missing something.

Anyway, I’ll jump to a snag with orthosonic lift. When I used a lightweight speaker and a small sled, I verified orthosonic lift produced by flow over the plank, so Bernoulli looks good with V_rms. But when I move the speaker on the scale with the sled, Newton's ghostly finger presses down on it and exactly cancels the lift. (Both shown at 45Hz, 2 watts RMS)

Similarly, if I place just a speaker with a ported faceplate on the scale there is no change in apparent mass with sonic flow (110Hz, 1.5 watts RMS). But when I raise and lower a horizontal flat wing in front of the port, the speaker registers the exact opposite of lift experienced by the wing. It would seem that orthosonic lift does not wish to bootstrap its engines. Yet conventional engines and wings using DC flow bootstrap themselves off runways everyday! Now I’m the one missing something.

 

[Faradave]

Before I start a new thread in the Aerospace forums for high frequency orthosonic lift, I thought I would make note of one more aspect of my low frequency work. Remember your introduction to oscilloscopes when they got you to combine sine wave signals on vertical and horizontal axes? The resulting ovoid Lissajous patterns should be physically realized by crossing sonic flows.

Since orthosonic lift seemingly depends upon RMS particle velocities, there are important limitations associated with higher amplitudes. We can only practically push the compressions and rarefactions so far. Energy requirements rapidly climb while increases in particle displacements diminish. I believe this can be alleviated by crossing two sonic flows at right angles and proper phase, with the compression of one flow corresponding to rarefaction in the other. The result, in my view, is vortigenic flow or mini-tornados, complete with attendant roof-pulling suction (lift).

My 13.3 gram, flat-topped, Styrofoam x-wing showed a 2 gram decrease in apparent mass at 70Hz, 2 watts RMS into each pair (4 ohms) of opposing woofers. At 10 watts/pair the wing hovered above the scale mount. When I tried to visualize the vortices with confetti and cork dust, the materials were quickly swallowed into the woofer ports, not to be seen again!