Nearly a year with no further comment. Disappointing.

Concept Question 17.2.1 :

http://ocw.mit.edu/courses/physics/8-01sc-physics-i-classical-mechanics-fall-2010/momentum/systems-center-of-mass-and-conservation-of-momentum/MIT8_01SC_coursenotes17.pdf

There are a few more obstacles to understanding the device but little point covering them in detail before acceptance of this fundamental issue.

I assume that since what was deemed impossible by most is now shown to be possible, the next order of business will be that other impossibility, overunity (strangely, considering the name of this forum).

Since the rotation of the apparatus is caused by the reaction,
it should produce energy equal the input less friction losses, IMHO.

This thread had me thinking again real deeply about angular momentum and all that is attached to it. After also reading your last post a similar "what-if" popped up in my head. I illustrated this.

What you have in the first setup is a big wheel and smaller wheels with motors undernearth attached to it. When the setup is at rest there is no rotation.
However when you start the motors the smaller wheels begin to spin and will have an angular momentum associated to them (green vector). Now because of newton's third law the stator of the motor, which is attached to the big wheel, will experience a counter torque. This counter torque is felt by the big wheel which will start to rotate too. This rotation too will have an angular momentum. It's obvious that this angular momentum is opposite to that of the smaller wheels. Since we're dealing with a closed system the total angular momentum has to remain 0. So nothing unusual here and all makes sense so far.

Now what if we remove the motor from the axles and flip it sideways and let it rotate the wheels by frictional contact. The torque of the axle of the motor will no longer be parallel to the angular momentum vector. We can also forget about the counter torque of the stator as the motor on the other side will spin in opposite direction canceling this torque.
So the only forces we end up with are the frictional contact forces. Unless my reasoning is wrong the only conclusion I end up with is that the bigger wheel will rotate in such a way that its angular momentum will be in the same direction of that of the smaller wheels. That is to say, the angular momentum of the closed system has increased without any outside forces.

Tusk this is basically your electromagnetic experiment however there you tried to get the force dead on the center. And your setup behaved, empirically at least, according to theory. But what happens if you intentionally positioned the motor "in front" or "behind of" the axle. Will the resulting rotation direction of the whole setup always be the same? That I would like to see .

Now I'm eager to hear what high school mistake I made in the previous reasoning .

Thanks broli, although you appear to have 'missed the boat' somewhere along the way (and since nobody has yet caught the thing this in no way reflects poorly on you, rather my attempts at explanation are no doubt sub par).

There are several important differences in our experiments (and my results/your hypothetical results); while you are apparently attempting to breach CoM, I have claimed no such breach and have inferred that such a breach is highly unlikely, and why. Also while I have stated on many occasions (this most recent instance with supporting reference to an M.I.T. document) that the linear motion of a body due to an applied force will be the same regardless of the point of application of force, you have not taken it into account in your proposed device. Under acceleration your main disk would rotate in the opposite direction to that specified, as a direct result of the phenomenon and I suspect in accordance with CoM.

If alternatively you intended your device to run at a constant velocity against various frictions and resistances it becomes another experiment entirely and completely unrelated to the PE. I did however suggest that the prototype PE have two disks mounted on the main rotor arm, so in this respect there is similarity. But to achieve OU the disk/s must be driven from a point coincident with the central axis for the reasons given in my previous post.

Being dependent on two separate phenomena, the first being the aforementioned linear motion (now confirmed) and the second being the frame of reference adjustment which allows the linear motion to manifest (converted to circular motion) thus avoiding the need to accelerate the drive unit, it is therefore required that both phenomena be understood for a full comprehension of the concept/device.

If you were convinced of the OU potential of the concept prior to such comprehension I assume you would spare no effort to grasp it; so this is really more of a trust issue. Curious that in the modern era someone giving something away for free should be held in so much suspicion; dare I say (in some quarters) even contempt.

I would much rather work with concrete numbers and examples

Fair enough brodi; I can allow that the roundabout be made of concrete if you find that helpful  But I will attempt to address your other questions and concerns in a more serious manner:

Your "man" that is pushing the round about in the circular system will no doubt experience the same reaction force. However in this case the reaction force will manifest as a torque which will rotate him.

And herein lies the problem with thought experiments. If I had specified either a small man or a tall cart we could have avoided this misadventure. So please excuse my failure to cover all the bases, a glance at the PE experimental apparatus will confirm that

1. the edge of the disk passes directly above the drive unit, which is mounted directly over the main axis, and
2. the drive unit rotates along with the main rotor arm (since it is mounted thereon).

Retrospectively then, we should stipulate that the edge of the roundabout passes directly over the head of the man, who stands dead centre and applies the motive force tangentially. As we restrict our model with ever more minutia it's serviceability is reduced and we run the risk of missing that boat yet again.

he now faces with the problem that the roundabout zooms past him ever so faster and his time to exert a force will go down every time. Am I not right here?

The roundabout would still 'zoom past him' when mounted in the park and unable to manifest linear motion. Any increase due to inertial and geometrical factors (which we can expect) would certainly keep him busy, but the example is intended as a conceptual aid rather than a detailed explanation. Once we transplant the basic concept over to the PE apparatus there can be much more productive discussion about this issue and how the EM drive unit deals with it. At this stage we might allow that the disk accelerating more rapidly seems not to be a hindrance to our stated intentions, which is the creation of a device which manifests more energy than is required to run it.

So the question is then if energy can "vanish" so easily when CoM must be conserved can the opposite also be true? So far you did not share any concrete numbers or design that would show this.

Actually I have presented data obtained from tests of the apparatus and also explained the design. Many have complained that the data is insufficient and have clearly failed to understand the design and it's real purpose. While it is true that the data requires some sophisticated logic to arrive at the stated conclusions, short of constructing a well engineered prototype we find ourselves at that stage of research and development where concepts and proofs have yet no offspring.

the force in my example #2 does act on the center of mass, being the axle of the small wheel. Since both forces are attached to the same base no rotation should occur. So this begs the question if there is a rotation of the bigger wheel, what force caused it?

The secondary reactive force at the axis of the two wheels. It takes time to assimilate new information so there is no shame in neglecting to include it. And in all fairness the M.I.T. reference fails to define the force clearly, but if you study the phenomenon it follows that the force must operate as I defined it. So the applied force on the wheels (by the motors) not only causes rotation of the wheels but also a reaction at the axis in the direction of the applied force and equal to it. Since this force is radially more distant from the main axis than the opposing equal reaction at the motors this would cause the larger wheel to rotate opposite to the direction you specified.

Back with the roundabout example, there exists a clear advantage due to the rearrangement of the frame of reference. But it seems equally clear that the manipulation of frames of reference is an acquired skill and not easily understood by the majority who have no cause to acquire it. Perhaps if you imagine the experiment taking place in space, so we can discard the cart; in the first instance our astronaut might employ a rocket pack to keep pace with the roundabout as it accelerates away. In the second instance, perhaps restricted to a circular path around him by virtue of the gravitational effect of a small black hole (which he must carefully avoid falling into) he can discard the rocket pack yet maintain a comparable rate of acceleration of the roundabout both in rotation and linear motion (converted to circular motion).

Any concerns about suitable purchase for the astronaut's exertions should be put aside; the experiment has many flaws (not least the black hole) but serves to illustrate the salient point, which is that linear acceleration requires more energy than remaining motionless, and converting the linear motion to a circular motion allows this advantage while maintaining a comparable energetic outcome.     

Please accept my apologies broli, I am not one to engage in brinksmanship or condescension but my attempts to fashion a 'watertight' explanation may camouflage what little of the social graces remain in this battered and rapidly aging skull. I am very happy to be discussing this with someone of an open mind who is able to maintain more than a passing interest. I can't promise lots of smiley faces but let me know if you interpret something as having negative undertones. When I refer to the difficulty experienced by anyone trying to grasp this material do not suppose that I am being 'high handed'; having spent the best part of three years struggling with it myself, I am well aware of how alien it must seem to others who are reading my poor interpretation in their spare time with little or no reason for confidence in the author. Indeed my chief concern is to place the thing in the hands of someone more capable than myself for whatever good may come of it.

So, 

Is your man, astronaut or alien attached to the main wheel/track, as is the case with your real word experiment, or does he have his own independent axis of rotation?

I hadn't intended that example to go beyond service as a brief illumination of the basic frame of reference manipulation. If it was a bucket of water we would both be drenched by this time. I may as well say that no, the man/astronaut is independent of the other elements in the experiment and must rotate himself at some small cost in effort; whereas the drive unit on the PE apparatus is (as you mentioned) mounted on the main rotor arm and therefore rotates with it at even lesser cost. And the primary reaction to any force applied to the disk by the drive unit goes back into the bench, since the line of force runs across the central axis which is bench mounted. There have been suggestions that this arrangement is only theoretical, and in practice is not fully realised; which is true enough, but in principle and within practical reason as much as any other machine is imperfect I think we can allow it.

Perhaps I can assume then (based on your replies) that you are 'up to speed' with both the secondary linear motion and also the general idea of frame of reference advantage - actually I'll call it frame of reference manipulation for now, since you may not allow there exists an advantage - at least insofar as the central position of the drive unit/man/astronaut changes things sufficiently to warrant further investigation.

In which case if I may forge ahead, and no doubt you will be aware of the following but I must state it for reasons of clarity; any body, be it static, in motion at a constant velocity or in motion and accelerating, is subject to an equilibrium of forces. When we read that the same force is applied to (e.g.) a bowling ball and a golf ball, this exposes the limitations of simplification in physics tutorials. The acceleration of the bowling ball will be far less than that of the golf ball, thus while the force might be measured as equal there is a point of force motion to consider, since there must be some finite period of time over which the force is applied. And the point of force motion in regards to the golf ball must accelerate at a greater rate, requiring additional energy. While there are certainly other ways to examine it, this may rightly be considered as a frame of reference issue.

When in the first instance our roundabout begins it's linear acceleration, we begin to have problems of the same ilk. Even if the roundabout were a flat disk and our applied force was constant and continuous due to the vigorous application of some hand held rotary tool, the man would still need to 'keep up' with the advancing cart. And we could rightly expect to take the measure of kinetic energy stored in both the rotation and linear motion of the apparatus at some point, and comparing it with the energy expended both in motivating the rotation and keeping pace with the linear motion against the reaction of that motivation there should be no discrepancy.

If I may swing past that one more time; ignoring the minutia whatever energy is expended keeping pace with the linear motion is manifest in the final kinetic energy of the linear motion of the roundabout/cart. And it is not inconceivable that by design this energy might be equal to the energy expended motivating the rotation.

Which might bring a sigh of relief to anyone rooting for UU (Under Unity), since it looked for a while there that we were getting two for the price of one. In reality we were putting two in and getting two out, the second input being the point of force motion.

But with apologies to the UU guys, our little frame of reference manipulation eliminates the point of force motion. Not the disk surface, which always had it's own advancing point of force motion issue, but the linear motion, now converted to circular with the point of application of force now static over the centre of the system. Yes the disk accelerates even more rapidly than before, so the point of force motion for the applied force on the disk itself is greater, but this comes with an increase in motion therefore no loss occurs.

So now we really are getting two for the price of one (ignoring the minutia, most of which can be mitigated in the engineering and design). And looking next to the PE apparatus, if we recover the energy stored in the motion of the rotor arm first so that it comes to a stop, when we then recover the energy stored in the rotation of the disk (from regenerative braking at the drive unit) our quirky little secondary linear motion reappears and the main rotor arm regains it's original motion - in the opposite direction - as the disk is brought to a stop. You can see this bonus feature in action on the PE device video hereunder (although I have no brake on the main rotor arm and must employ the phenomenon to halt the initial rotation; but it manifests well toward the end of the run):

http://www.youtube.com/watch?v=dG8YOp_njFs&feature=youtu.be

Three for the price of one 

in both your experiments the inner wheel did have an initial rotational velocity. How can we rule out that this initial kinetic energy is not equal to the final one?

I assume here that you are referring to the two videos of the PE apparatus, due to a stalling effect at low rpm the disk must be hand started. It's not clear to me what point of logic you are employing in this instance; if I had corrected the stalling problem and started from a motionless state using the EM drive unit there could be no such question yet the apparatus would behave as before, unless you are suggesting that by hand starting the device I can somehow induce the reverse rotation at the end of the test? In which case may I suggest that you perform a simple build yourself, I found that a small disk mounted on an arm which in turn is mounted on a handle (both free to rotate) and counterbalanced, allows a 'hands on' experience which demonstrates readily the motions involved both in acceleration and deceleration of the disk.     

if you then end up with any additional rotation you could start to consider it "free"

Working backwards then I expect that the complimentary reverse rotational motion of the main rotor arm under drive unit braking of the disk might seem quite paradoxical. Just viewing the process at the fundamental level it soon becomes obvious that :

1. the total potential energy (or kinetic energy) of the apparatus (disk rotation + main rotor arm rotation) = the total input energy (less inefficiencies).

2. once the energy is recovered from these motions there should be no remaining energy; all motion should cease, not reverse.   

3. since the main rotor arm motion does indeed reverse in full measure (in comparison to the original motion) there can be only one conclusion.

Perhaps I should have made this point sooner, instead of attempting to hold back the tide of disbelief regarding both the secondary linear motion and the frame of reference advantage.

Your inner wheel and rotating arm setup is not that complex to calculate its moment of inertia from there you can easily derive the kinetic energy based on final angular velocity. Imo this step is key if you want to do any meaningful energy comparisons.

It would be significantly easier to run the numbers on a hypothetical apparatus, that way the design can incorporate features (i.e. mass distribution etc) more convenient for the purpose. The input force can be specified arbitrarily, with the secondary reactive force equal to it; the mass of the various elements is again arbitrary, although some value which might reasonably produce realistic values for the various motions might be in order. I think the disk should have a mass bias around the outer edge for best results, ideally all the mass around a single circumference of known radius would make things easier, and actually I would go for two identical disks and a weightless main rotor arm.

While this would represent an idealised apparatus, it would be a good starting point since any result in terms of output close to 100% would suggest no advantage. But if the equations allow a reversal of motion in the main rotor arm in full measure of the original motion then you will have some indication that the numbers are adding up correctly (since this is suggested by observation).

But I'll leave that for someone else. Previous experience presenting mathematical proofs indicates the need to employ another approach; nothing chokes off a thread like a page of equations. If this were a physics forum, maybe; although the typical physicist would likely lose interest at first sight of the abstract, which would appear foolish at best against the background of conventional wisdom, especially considering the simplicity of the concept.

Fair enough broli, I'll backtrack a little since I failed to emphasise an important point. From memory I mentioned the additional energy in the disk (I always refer to the two main components as the disk and the rotor arm btw) which manifests due to the inertia of the disk and (I suppose we could say) basic geometry:

I can't tell how fast the inner wheel is spinning but it sure looks much faster than the starting condition which would already be a violation of conservation of angular momentum right there, and every other moment when the main wheel reverses, it just LOOKS like the inner wheel has way too much angular momentum than it started with.


So, and I believe I got it wrong again, to conclude everything what you are saying is you ended up with more angular momentum than you started with in a closed system?

I can't recommend strongly enough that you construct a simple freewheeling apparatus; it really does assist in understanding the dynamics. I'll proceed as if you had one to hand, if not then perhaps you can imagine it, else sketch out a quick diagram.

Let's allow that from motionless, the rotor arm begins to accelerate by whatever means (we'll work in a clockwise direction for the rotor arm). Since the disk has inertia it will maintain it's orientation (notwithstanding friction, air resistance etc) so that one turn around on the rotor arm causes one rotation of the disk in an anticlockwise direction according to the frame of reference of the rotor arm (included in this frame of reference is the axis of the arm thus also the drive unit when dealing with the PE apparatus).

Back with the freewheeling model, in the observer's frame of reference the disk manifests no rotation. (notwithstanding friction, air resistance etc). But in the frame of reference of the rotor arm (thus the drive unit on the PE) the disk manifests rotational motion.

Note that this anticlockwise rotation serves to advance our efforts to rotate the disk (with the EM drive unit on the PE) since if the rotor arm is compelled to rotate clockwise (by the secondary linear force at the axis of the disk) then we must be driving the disk anticlockwise.

So here again an advantage; if you check the data from a typical experiment you will observe that the 'main rotor free' test uses significantly less power and achieves significantly higher RPM in an equal period.

http://img201.imageshack.us/img201/5488/paratach2.jpg

As we motivate the disk, the secondary motion of the rotor arm serves to advance the disk rotation in our favour, in the frame of reference of the drive unit.

I imagine if that were the sole advantage of the device it would be enough to attract investors. There are at least two strikes against this however; first and foremost I am not motivated by profit, and running a close second the concept goes so far beyond this simple phenomenon in advantage as to beggar belief.

There is no violation of CoM. This entire concept has it's roots in the manipulation of frames of reference. As such, kinetic energy (which is 'not invariant') seemingly 'pops out of nowhere', in truth I suspect with no actual violation of CoE (apparent but not actual). The frame of reference issue is known, but nobody has taken advantage of it before. So that when energy unexpectedly manifests, is it a violation of CoE if it does so due to a frame of reference manipulation?

Whatever the consensus, energy is gushing out of this device from the several holes it makes in convention. The decision you must make broli, is whether or not you are communicating with a person of sufficient intelligence and integrity to be trusted, since the concept itself seems initially quite incredible and even alien. You may very well be the first to actually grasp it (after my own faltering efforts).