A.R.T.R.R.

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Note: I've previously posted this text elsewhere on the Internet, but I have re-ordered it here for the HalfBakery, which prefers gadgetry over hypothesis. Certain relevant background information (in addition to the Part One stuff at the bottom here) can be found at the "Gravity Waves" link; the "associated sketch" referenced in this text is also provided at a link below.

This synopsis was not part of the original text:
Part Two: A device is described which should exhibit unusual movement when activated. It would RESEMBLE that impossible type of device known as a "reactionless drive", but its operating principle allows for Conservation of Momentum, via emission of gravity waves. Other developers of "reactionless drives" may be employing the same fundamental operating principle without realizing it, but at purely mechanical speeds (like 1500RPM), the degree to which Action and Reaction might become unbalanced ("out of phase") is barely notice-able. Therefore much controversy exists regarding those devices; I'll post a couple of links so you can see for yourself. On the other hand, this proof-of-principle device should be run at about 100 times the frequency of any purely-mechanical "reactionless drive", and as a result any associated "phase angle" should be so much greater as to leave no doubt about whether or not its operating principle is valid.
Part One: A hypothesis and thought-experiment are offered, describing the weird and usually-ignored aspect of Nature that should permit the device to work. Basically, the way ANY object responds to an applied force depends upon the details of how it is applied. It is perfectly possible for one arrangement of forces to cause an object to move almost immediately, and for another arrangement of forces to cause only PART of it to move almost immediately (the rest of the object waits for the forces to arrive). This fact is exploitable by the design of the Part Two device, simply because the speed of electricity is enormously faster than the speed of sound; when raced against each other, there is little doubt that forces can be applied to an object faster than some responses can occur. End of synopsis.
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IS IT POSSIBLE? Can Action and Reaction really get out of phase with each other, radiating Momentum and causing unidirectional motion? Well, the reference cited below describes multiple repeated observations of a 3-degree phase angle in two different purely mechanical systems, that ran at 1500RPM (a mere 25Hertz). But they weren't trying to use the phenomenon for propulsion; they were simply trying to verify someone else's claim of achieving a 45-degree phase angle. I suppose as soon as somebody can afford to build this proof-of-principle device (not I, alas!), then we will find out whether or not Alternating Response Times can usefully "Rectify" Reaction.

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Reference Tree Root: "Detesters, Phasers, and Dean Drives" by G. Harry Stine, "ANALOG Science Fiction/Science Fact", June 1976

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Part Two - Physical Experiment

The acronym ARTRR was created so that it could be used, like LASER, to become the name for any device that incorporates the operating principle specified in the source-phrase. --IF there actually is anything "to" that operating principle, of course! In pronunciation -- should it ever be worth pronouncing, of course -- it most simply can rhyme with "barter".

There IS a Problem with respect to constructing a stand-alone artrr, that we might want to propel our spaceships. The Problem starts off with the fact at an artrr must consist of at least two component parts that interact with each other -- as do, for example, the stator and rotor of an electric motor. Well, we want those two components to interact in a very special way, more-or-less as in this Operation Description:

1) Forces are brought into existence between the two Components. I'll assume they are caused by electromagnets, since we know all about those, and they are commonly available and very versatile.

2) Suppose Component "A", as a result of the applied forces, is supposed to move this way -->. In accordance with Action and Reaction, Component "B" would start to move <--.

3) In the course of that simple event, one of those two parts -- I'll pick "A" -- must experience a comparatively long Response Time, while "B" must experience a comparatively short Response Time. (NOTE: For details behind this "Response Time" stuff, see Part One below.)

4) A minimal duration of time passes (remember we want quite high frequencies here!), and a new set of electromagnets are activated.

5) Component "A" now moves this way <-- with a short response time, while "B" is supposed to move --> with a long response time.

6) Repeat the alternating energizings of the electromagnets, at some thousands of Hertz. Ferrofluid-core electromagnets, with zero hysteresis, will likely be required.

7) Notice that both short-response motions, of the two parts, are in the same direction. We want each of them to act similarly to the battering-ram experiment. If Rectified Reaction occurs, then one way to describe what's going on is to say that each part "holds still" due to its inertia, for some fraction of a second (or long response time), while the other's inertia is quickly overcome (due to short response time). Resulting motion might be inch-worm fashion -- but small fractions of an inch, thousands of times per second.

So, do you see the Problem? If Component "B" experiences a short response time, then presumably forces are being applied to it at many places. MEANWHILE, "A" must have the same total force applied to it -- presumably at just one location -- such that it experiences a long response time. HOW DO WE MAP a multitude of force-application-points on "B" to a single point on "A" (AND vice-versa, for the other half of the cycle)?!?!?!

Well, believe it or not, this is a solvable design problem. Please see the associated sketch. It IS just a sketch, and not a blueprint, of the simplest way I know to apply the artrr principle. If it works, it will be a "proof of principle" device. It will not be efficient enough for much use as anything more than a toy or learning tool, except maybe in the zero-G space environment. To accomplish significant tasks with an artrr (like lifting itself and a payload against Earth's gravity) will require much higher efficiency.

The sketch is plainly marked to show the necessary interacting identical Components "A" and "B". Each circular ring has an interior region with six interaction sites. Each ring also has, at a single point on the ring, six spokes for additional interaction sites. The relative orientations are such that if either ring is placed in the X&Y plane, then those six connected spokes can occupy the X&Z plane (as portrayed). The two rings must be constructed together, so that they resemble two links in a heavy chain. Note the interaction site marked "C"; this is an edge-on view of an interaction AREA, perhaps two pancake-shaped electromagnets. Also, one interaction site does double-duty inside both rings -- it is shared between them -- so that there is a total of only eleven interaction sites.

Now, with respect to the preceding Operation Description, item (1) involves activating the six interaction sites inside the "B" ring. Every part of that Component will experience part of the total applied force in a short time, as required by item (3). Yes, I know there is a complication regarding all those spokes attached at one point of "B". The unequal-response-time aspect can be resolved by making them a little shorter (and the interior-ring spokes a little longer) than portrayed in the SKETCH (and each ring won't actually pass through the center of the other, which is also different from the portrayal). The unequal-mass aspect will require a greater force to be applied at the shared central interaction site, than at the other five sites inside the "B" ring. OK?

Next, in order for Component "A" to move --> and "B" to move <-- as specified in item (2) above, three of the interaction sites inside the "B" ring should experience Attraction, and the other three should experience Repulsion. Then, in accordance with item (4), the six interaction sites inside "B" are turned off, and the six inside "A" are activated. Of course, one of those six is the shared interaction site, that had just been switched off. That's OK; now we want that particular site to experience Attraction instead of the former Repulsion, to help cause the motions specified in item (5).

(Another finicky detail rears its ugly head. If before we turned this putative artrr on, all the interaction-site gaps between the two Components were equal-sized, then after the first group of sites were activated, some of those gaps will have shrunk, and some will have grown. This means when the alternate group of sites is activated, the Inverse-Square Law will affect the electromagnetic forces that we want to use to create Attractions and Repulsions. The solution, of course, is to implement some feedback controls, so that we can energize the electromagnets appropriately less when the gap has shrunk, and appropriately more when the gap has grown.)

To review the Operation Description in item (7) would be a bit redundant, now that we've seen how the sketch accommodates the requirements. So let's focus a little more on how this design solves the specified Problem: As the initial group of forces start to spread out from the interaction sites (items 1-3), note that six separate regions of Component "B" receive portions of the overall Force of Action. But for Component "A", the total Force of Reaction consists of six parts that all converge at one location on its ring, AFTER which that total has to spread all around the ring. This obviously means that "A" will indeed have a rather longer Response Time than "B", when the first group of forces is applied. Likewise, when the Alternate group of forces (items 4-5) do their thing, then inside "A" there will be six regions simultaneously affected with Action (short Response Time), while the Reaction can only affect "B" after converging through a single point (long Response Time).

Finally, regarding the appropriate operating frequency of an artrr: This should be just less than whatever value would be too high for the shorter Response Time. That is, if the fast Response occurs in one ten-thousandth of a second, then the maximum operating frequency would be almost ten thousand cycles per second, or 10KHz. Think of the device as having three "behavior modes", depending on frequency. At the lowest possible frequencies it would simply oscillate in ordinary Newtonian fashion, and go nowhere. At too-high frequencies it will also go nowhere, and may barely even vibrate. Only in some middle range of frequencies, too fast for the long Response Time and not too fast for the short Response Time, can the preceding Operation Description apply, for an artrr to do its thing. And the most efficient frequency is always at the high end of that middle range.

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Part One - Hypothesis and Thought-Experiment

Actually, that acronym is a bit misleading. The Law of Action and Reaction is not something that can be "rectified". (In case you don't know what "rectify" is likely to mean here, there is in the field of Electronics a device called a "rectifier" that allows electricity to move through it in one direction, but blocks its movement in the other direction.) It is possible that the word "Rectify" in that acronym could be replaced with "Rotate", but that would be even more confusing to the uninitiated. So, let the initiation begin!

Consider an old-fashioned battering ram. This is basically a big tree trunk with a lot of handles attached. Laying on the ground, a gang of guys divides into two groups, one on each side of the tree trunk, then picks it up by the handles, and carries it to a door that needs to be battered. A fancier version has the ram suspended from a framework, so that once the whole framework (on wheels) is moved to the door, all the guys have to do is swing the ram so its end moves toward and away-from the door. They don't have to lift its weight. OK now, let's imagine a modest contest involving a very special battering ram, not too thick, but so long that it has two thousand handles, needing a thousand guys on each side of the thing -- and Superman. We'll assume he's plenty strong enough to pick this battering ram up by himself, and tough enough so that the thing would shiver into pieces if it was actually aimed at his chest, but neither of those is the contest here....

All we are going to do is SWING this ultra-long battering ram, back and forth, as fast as possible. Yes, this is in defiance of the natural swing of the suspended thing, but I'm not saying we have to swing it very far in each direction. A centimeter or two will be fine. SO, let's see the two thousand men try this first. Due to the length of this battering ram, and the speed of sound, we first need to rig up a speaker system, say, every three meters. The Team Leader speaks into the microphone, "Forth! Back! Forth! Back!..." Now all the men can hear those words coming from the speakers at pretty much the same time, and can apply their efforts pretty much in unison (especially after getting into the swing of things, pun not particularly intended).

Do you have any doubts that the two thousand men can quickly move this battering ram back and forth? Each one, after all, is only applying effort to a small part of the whole thing, and we didn't specify a Sequoia-thick trunk!

OK, Superman, it's your turn; please stand at one END of the ram, and do your thing. What's that? You say the contest is rigged? The far end isn't going to budge when you push and pull on the near end -- at least not immediately? The speed of sound INSIDE THE BATTERING RAM is the problem? Yes! You're right, Superman; we suspected you were knowledgeable enough to realize that. Thanks, anyway! Oh -- please don't leave yet! There is one more thing to try, not a contest but an experiment, in a few minutes.... Thanks again!

What Superman (and any decent physicist) knows is that mechanical forces travel at the speed of sound within the substances of whatever experiences those forces. The shock wave from a depth charge IS a high-intensity sound wave, and travels at the speed of sound in water, from the explosion to a submarine, for example. Two thousand separate impulses, applied in unison all along the length of the super-long battering ram, are plenty to move it quickly. But one huge impulse applied at one end of the thing -- that impulse has to travel the whole length, at the speed of sound inside the ram, while the far end simply waits, before that end can experience any iota of that impulse, no matter how Super. It is simply impossible to apply a force at just one point, and cause that battering ram to move as a whole faster than the limitation enforced by the speed of sound. The thing would probably shiver into pieces first.

Now it happens that that simple fact, regarding the speed of mechanical forces inside various substances, can almost entirely be ignored in everyday activities. Such activities usually involve short distances, modest forces, and less than a millisecond of "waiting" time, as mechanical forces propagate through ordinary objects. Introductory Newtonian Mechanics doesn't even bother to mention this aspect of Nature. The Advanced stuff goes into some of what I am describing here, but the Physics Community has a whole has, so far as I know, never really examined the wider consequences of the experiment described below. (A FEW individual physicists did, but they were ignored. More on that later.)

Now we're almost ready for the experiment. First, though, please recall that the battering ram was described as being "very special". The only special thing we want here is that it be as unbreakable as possible. It must NOT "shiver into pieces", no matter what. So, physicists, don't worry about that aspect of Reality here; just concentrate on the Equation of Motion for the battering ram, in this experiment. Thanks!

OK, Superman, please stand near that end, there, as before. All the rest of you guys, here's what we want you to do: When you hear the word "Forth", you will each apply a short, sharp, jerk to your battering ram handle, toward Superman, and then let it coast. Superman, let it coast toward you until you hear the word "Back" -- then apply a powerful force to that end of the battering ram, to push it back. That's all. We just want a simple oscillation, with equal-magnitude forces being applied, pushing it forth and back. Only the WAY those forces are applied will be different...get ready!

For the sake of simplicity, let's assume that when Superman applies his Super force to the end of the battering ram, it takes exactly one whole second for that mechanical force to reach the far end. Also, we are going to say, "Forth! Back! Forth! Back!..." at the rate of four words per second. Physicists, what IS the Equation of Motion for the battering ram?

I mentioned earlier that some of this has been studied before, but the results were ignored. The equations are not pretty to anyone who hates math, but if they actually describe Real Physics -- and I am NOT claiming that they must! -- then here is the gist of what they have to say, as applied here: The battering ram will experience some overall and inexorable motion toward Superman (who is not expected to remain in place). But how can that be, if the applied forces are equal and opposite (regardless of how-applied)? The Law of Conservation of Momentum offers strong objection to any such scenario. Well, for the moment, please accept my assurances that there is no desire here to violate that Law (details in due course).

The key factor is that one-second delay, between Superman's effort and any motion of the far end of the battering ram. We could say, "The ram as a whole exhibits a long response time to the applied force." When the two thousand men apply their small forces, the whole battering ram experiences the sum in the usual millisecond or so. "The ram exhibits a short response time to the applied force." Since we are Alternating the application of the forces, the differing Response Times cannot help but have some effect on this system. After all, the two thousand men are applying forces that almost-immediately cause the ram to move toward Superman, twice per second, while every time Superman shoves the ram, one whole second must pass before it can fully respond! Now perhaps I have exaggerated by describing the claimed consequences as managing to Rectify Reaction, but if the ram actually does have some overall motion toward Superman, then the casual observer will probably not complain. (And I DEFINITELY need to say that at a mere 2 forth-and-back cycles per second, the magnitude of "rectification" is likely just barely noticeable -- PARTIAL rectification is all we can hope for.)

In more detail, the not-pretty equations I mentioned describe Action and Reaction getting "out of phase" with each other, as a result of including the response times. For the nonphysicist reading this, a simple way to picture that is to first think of an old-fashioned analog clock, with its moving hands. Now throw out the mechanism, and put two identical-length hands on the face of that clock. Set them so that one points at the 12 and one points at the 6. Thus they are equal in magnitude and opposite in direction, just like ordinary Action and Reaction. Well, to whatever extent it MIGHT be possible for Action and Reaction to get out-of-phase with each other, that is the extent to which those two clock hands can manage to no-longer point in exactly opposite directions.

Continuing this phase stuff for the nonphysicist, please refer to the clock-like circles in the associated sketch. Each [A] arrow represents an amount of Action, and each [R] arrow represents an equal amount of Reaction. Now suppose [R] could be affected so it points at the 5 on a clock-face. In terms of geometry, that adjustment is a 30-degree change, or "phase angle", from its original alignment. Pretend that new alignment for [R] is the long side (hypotenuse) of a right-angle triangle. Well, that triangle will have its medium-length side -- marked on the sketch as [R'] -- still aligned to point toward the 6. The length of [R'], for a 30-degree angle, is about 87% of the length of [R]. In Physics, when an arrow is used to represent a Force, the length of that arrow -- or "vector" -- indicates its magnitude. If we were describing something that really could happen to Action and Reaction, then our 100% Action of the [A] arrow is now only about 87% balanced by the Reaction represented by the [R'] arrow. The difference of about 13% then means some overall motion in direction [A], of whatever-it-is that is experiencing out-of-phase Action and Reaction. (And what about that rotated [R] vector? Oddly enough, this does not represent any tendency toward motion in some sideways direction; it represents another thing that is explained a little later in the text.)

Of course, in the battering-ram experiment, a 30-degree phase angle may be much too high. YES, I know that in Ordinary Newtonian Physics, a Action/Reaction phase angle of even 0.01 degree is totally unattainable! But that battering ram thought-experiment is not hardly something you encounter in Ordinary Newtonian Physics, so, physicists, please derive its Equation of Motion before denouncing this essay. To continue: *IF* the Reaction vector gets out-of-phase at all, relative to the Action vector, then MAYBE we will be lucky enough to see a couple of degrees (from the 30-minute mark to the 29-minute mark on a clock face is more than that: six degrees). Still, ANY degree of out-of-phase activity means that SOME overall unidirectional motion should become possible. The results of those old ignored equations depend on the frequency of the applied forces -- 2 cycles per second is trivial, but a hundred thousand Hertz might Rotate Reaction on the clock face from the 6 almost to the 3! That's a phase angle of almost ninety degrees. Please note that those old equations say that a ninety-degree phase angle is actually an unattainable limit -- kind of like trying to reach the speed of light. Either limit can be approached arbitrarily closely, but can never actually be reached. I personally find it quite intriguing that in this era of gigaHertz technology, using a mere 100kiloHertz might give us enough "rectified reaction" to easily move off the Earth and across the Solar System. Isn't it worth FINDING OUT if there is any truth to that? See Part Two.

Now what about that Law of Conservation of Momentum? Well, consider the Equations of Electromagnetism for a moment. Early experimenters with Alternating Current were accused of trying to pull a scam -- since the AVERAGE current is zero, surely no real work could be done by Alternating Current! But the accusers were wrong, what we might here call the "response time" provided by the delay between opposite flows of current DOES allow work to be done; furthermore, those Electromagnetism Equations allowed momentum to be literally radiated away (as photons), and so AC power is everywhere, today. OK, then, the few early ignored physicists who were investigating out-of-phase Action and Reaction decided that a similar loophole was possible here. That is, since we are jerking Inertial Masses around, and since those are considered equivalent or even identical to Gravitational Masses, then to whatever extent a merely accelerated mass can wimpily radiate a weak gravity wave, it seems that a JERKED mass can radiate momentum MUCH better...and so the Conservation Law stays in force. More specifically, the greater that the Reaction vector becomes out-of-phase with the Action vector, the greater the radiation of Momentum.

--As a check, consider the late Dr. Joseph Weber's gravity-wave detectors. They were supposed to operate by extracting a tiny bit of energy from a passing gravity wave, and converting it into distortions (stresses) of the shape of the detector. Now recall Time Reversal Symmetry, in which most simple events can work both forwards and in-reverse -- this rule implies a deliberately-stressed object might be able to emit a gravity wave. And surely there are plenty of stresses going on inside that battering-ram experiment!!! (Not to mention that Dr. Weber claimed his detectors were detecting too many gravity waves. Could some of them have been coming from such stressed-mass events as trees falling in the woods, auto wrecks, pile drivers, the explosions of war, and perhaps even the hammered nails of the construction industry?)