Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1799071 times)

Offline deltaMass

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If I knew that...I'd have better answers!

Offline birchoff

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It's really not about personalities, but rather about our precious corpus of knowledge we call science. EmDrive as described violates conservation of momentum, which is linked, via Noether's symmetry theory, to the invariance of physics under displacements in space. Or in layman's terms, the electron charge is the same in Hoboken as it is in Hampstead. Everyone (with at least one notable exception and his acolyte) understands this. Therefore, if EmDrive works then it topples the entire edifice of physics. This is not a small thing, and one should expect a suitably graded response from science professionals. It's perfectly predictable.

I would have to disagree entirely. Why is it ok to assume that the Emdrive must work the way Shawyer's Theory says it does? My personally problem with your argument is that all the criticism has the built in assumption that If the EmDrive works Shawyer's theory must be right. When it could also be possible that If the EmDrive works Shawyer's theory cannot completely be used to explain it. I suspect that at best his thrust scaling predictions will be a good approximation.

Online SeeShells

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...
The moment you're no longer morally allowed to question things that are true, only by appearance, you slip into what i would call "scientific fundamentalism". A dogmatic attitude has never been very productive...
...

As long as Sean Carroll is not trying to forbid or even impede discussions or experiments on EMdrive the term fundamentalism seems a bit exaggerated. Fundamentalism kills those days, you know, as in the past. He is just stating an opinion, as an expert in evaluation of crazy ideas of how stuff works at a basic level, he must see thousands a year. In not so diplomatic terms all right, but he is not talking to kids that Santa Claus doesn't exist (even if he is still working on the Grinch).

Talking of productivity, what was the productivity in terms of confirmed effects/knowledge originating from the fringe science scene lately, compared to the productivity of research starting from speculative but academic subjects ? Who is to designate what is fringe if not the academics ? Who's faults if practically all fringe claims go nowhere, dogmatic academics or not so fun physical reality ?
It wasn't that long ago I remember when they were doing the building of CERN to find the Higgs some called it a money pit and fringe science.
Shell

Offline birchoff

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I mostly agree, but with a few caveats:

- Yes, lots of people would like to see physics or big science fail for once. Why? because we are human, that's why. We are basically irrational apes and we root for the underdog and hate the authority "restricting" us. Science is not really an enemy of course, it's just the method and the changing dialectic discourse of what we know about the world thanks to that method, but in the eye of many, it represents the closet thing to ecclesiastic authority. And even more now, when it has imbibed itself (and being mixed up) with some political and societal opinions (e.g. climate politics and its detractors are always fighting for saying they have the scientific truth on their side).

Great way of wording it.  Some people see laws like COE and COM, the speed of light, etc., as cruelly restrictive, and would love to see them come crashing down.

Quote
 
- The impact of this being true and the unfairness of having Carroll's or other people's egos bruised are hardly on the same league. If the fans are wrong, the critics can gloat but hardly anyone else will be impacted in particular, on the contrary case, the critics get the bashing and gloating by virtue of being in the tiny minority vs a spiteful majority. But so what? the critics won't die because of it and if something like this is true, life as we know it will change and everyone on Earth (including the critics)  will be impacted.

I don't follow the logic here.  If I believe X, and X has great implications if true and no implications if false, do I somehow have the moral high ground?  Should Carroll have been kinder simply because the emdrive being true would be awesome?  Are all the smug posts saying "I told you so!" (I'm talking on the web in general here, not in this thread) after the recent Tajmar result okay because they are in the minority, fighting the "spiteful" majority?

I guess what I'm saying is, that yes, Carroll probably is attached to his view of the universe.  Likewise, it's pretty clear from reading this forum that some people are attached to the emdrive being true, and would be very disappointed to find out otherwise.  This makes for terrible science, because it means "believers" have an emotional incentive to find positive results, and "sceptics" have an emotional incentive to find null results.  Carroll's comments don't help the situation, but the comments going after him are indicative that this thread is falling into the exact same trap.

If Carroll has made his comments about the nonexistence of cold fusion or faster than light neutrinos, would he have gotten the same response?       

Are we at the point in humanity's evolution where it is impossible to disagree with an idea without being rude?

Online SeeShells

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If I knew that...I'd have better answers!
And if we knew more we would have a GUT down pat. ;)

Offline birchoff

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Wall, I disagree especially when you say taking life less seriously. This is not the case. I recognize, when you can be critique, but I also recognize, when someone show arogance as Mr. Caroll unfortunately did.

Those people use to fall for this side because they know their status and are sure in their knowledge. So, few insults would not hurt only support my work right? Agorance is easy. True critic trough experiments is hard and time costing. None of you here that go for critic actually did not done any of that, even when I recognize you have knowledge I will never have.

As I said you guys have good critic and you are polite thank you for that, but there is too much experiments already done and none from the "Critic" side. Your knowledge and logic is great, but I really lack some data from you guys.

Edit: Sorry for my English it is really not good.
No worries on the English.

It's no surprise data from critics is short, where is their incentive?  A "believer", if it works out as planned, will be on the ground floor of the greatest breakthrough for a century, or have the opportunity to get some good IP or even a Nobel prize.  The "skeptic", if everything goes as planned for them, will just manage to prove a largely anonymous internet crowd wrong, and will probably be resented for doing so.  The incentives make no sense for a skeptic to actually do any experimenting themselves.

So I suppose in that sense, it is the believers who will have to carry the day after all, as it requires a non zero  belief in the emdrive to bother testing it in the first place.

The motivation for critics to provide experimental data and protocols showing null results. Is continuing to push science further. I could potentially understand before the EagleWorks experiments. But now, If this is all experimental artifact. Then humanity needs documentation on what is going wrong in these experiments.

Online SeeShells

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If I knew that...I'd have better answers!
And if we knew more we would have a GUT down pat. ;)
I had a friend ask me today if it was even worth it, you know exploring the solar system because we had probes sent to all the planets and not much more needed to be done. The money could be spent here on earth feeding the hungry masses.
I sent him this.
http://www.space.com/30074-trillion-dollar-asteroid-2011-uw158-earth-flyby.html

Offline deltaMass

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I did not know that space radar was this awesome...wow.

Online QuantumG

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The only threads where being off-topic is a virtue.
Jeff Bezos has billions to spend on rockets and can go at whatever pace he likes! Wow! What pace is he going at? Well... have you heard of Zeno's paradox?

Offline birchoff

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If I knew that...I'd have better answers!
And if we knew more we would have a GUT down pat. ;)
I had a friend ask me today if it was even worth it, you know exploring the solar system because we had probes sent to all the planets and not much more needed to be done. The money could be spent here on earth feeding the hungry masses.
I sent him this.
http://www.space.com/30074-trillion-dollar-asteroid-2011-uw158-earth-flyby.html

This is why I think talking to the unwashed masses about space purely in the context of exploration wont work. Its also why I am really really looking forward to Private Industry doing their thing in space. Establishing a permanent foot hold in our solar system not just around our planet IS about feeding the hungry masses. The planet we live on is truly an Eden. But unless we want to enact child bearing control policies like china did. We need to vastly grow humanities resource base. Expanding into our solar system will do exactly that. How many inventions and ideas are sitting on R&D drawing boards because they need scarce metals to build them.

Offline deltaMass

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It's really not about personalities, but rather about our precious corpus of knowledge we call science. EmDrive as described violates conservation of momentum, which is linked, via Noether's symmetry theory, to the invariance of physics under displacements in space. Or in layman's terms, the electron charge is the same in Hoboken as it is in Hampstead. Everyone (with at least one notable exception and his acolyte) understands this. Therefore, if EmDrive works then it topples the entire edifice of physics. This is not a small thing, and one should expect a suitably graded response from science professionals. It's perfectly predictable.

I would have to disagree entirely. Why is it ok to assume that the Emdrive must work the way Shawyer's Theory says it does? My personally problem with your argument is that all the criticism has the built in assumption that If the EmDrive works Shawyer's theory must be right. When it could also be possible that If the EmDrive works Shawyer's theory cannot completely be used to explain it. I suspect that at best his thrust scaling predictions will be a good approximation.
I do believe that you've misunderstood me, Sir.

What I said in no way reflects upon Shawyer's theory or lack thereof. It's a general comment about how a mainstream professional scientist, accustomed to making media pronouncements and well-known to the media, would be expected to react. Really, there are no surprises here. He's almost duty bound to call it crap.

If I were outraged by this and wished to mount a counter-argument, I would not go the well-trodden route taken by the fringe and the ignorami by portraying scientists as white lab-coated mandarins floating about in their expensive laboratories clutching clipboards, condescending to everybody, and dishing out pronouncements like stone tablets.

Instead, I'd simply quote Feynman (if I could find the quote  :-[) where he talks about Mother Nature as the Mistress of all science, and that at the end of the day, since all we can learn is Her data, all we have is that data, and we must perforce follow that data. If our theory contradicts the data, and we have triple-checked the integrity of our data-taking, then it's our theory that has to go, because the data is the boss.


« Last Edit: 07/30/2015 12:05 AM by deltaMass »

Offline birchoff

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It's really not about personalities, but rather about our precious corpus of knowledge we call science. EmDrive as described violates conservation of momentum, which is linked, via Noether's symmetry theory, to the invariance of physics under displacements in space. Or in layman's terms, the electron charge is the same in Hoboken as it is in Hampstead. Everyone (with at least one notable exception and his acolyte) understands this. Therefore, if EmDrive works then it topples the entire edifice of physics. This is not a small thing, and one should expect a suitably graded response from science professionals. It's perfectly predictable.

I would have to disagree entirely. Why is it ok to assume that the Emdrive must work the way Shawyer's Theory says it does? My personally problem with your argument is that all the criticism has the built in assumption that If the EmDrive works Shawyer's theory must be right. When it could also be possible that If the EmDrive works Shawyer's theory cannot completely be used to explain it. I suspect that at best his thrust scaling predictions will be a good approximation.
I do believe that you've misunderstood me, Sir.

What I said in no way reflects upon Shawyer's theory or lack thereof. It's a general comment about how a mainstream professional scientist, accustomed to making media pronouncements and well-known to the media, would be expected to react. Really, there are no surprises here. He's almost duty bound to call it crap.

If I were outraged by this and wished to mount a counter-argument, I would not go the well-trodden route taken by the fringe and the ignorami by portraying scientists as white lab-coated mandarins floating about in their expensive laboratories clutching clipboards, condescending to everybody, and dishing out pronouncements like stone tablets.

Instead, I'd simply quote Feynman (if I could find the quote  :-[) where he talks about Mother Nature as the Mistress of all science, and that at the end of the day, since all we can learn is Her data, all we have is that data, and we must perforce follow that data. If our theory contradicts the data, and we have triple-checked the integrity of our data-taking, then it's our theory that has to go, because the data is the boss.
My apologies If I could give you 10 likes for your comment I would have... one will have to suffice.

Offline frobnicat

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If he is still using the ARC balance, then it uses special "C-flexural" bearings. These come with an intrinsic restoring force and prevent the balance from acting like a ballistic galvanometer.
http://c-flex.com/

These bearings are now beloved these many years by Woodward. As a matter of fact, right after the "null result report" by Tajmar and Buldrini re. a Woodward Effect experiment they reported upon at STAIF2006, Tom Mahood (an ex-student of Woodward whose M.Sc. thesis was on the Woodward Effect) went off to his well-equipped home workshop and ran up the "ARClite", which Woodward has used ever since. It was a copy of the Buldrini design.

Therefore, it is most likely that this persistent measured force is a real force and really is persistent.

He says he used a knife edge balance, which is what's shown in the photo. There is no bearing. The only restoring force is gravity acting on the counter weight. He's counter-balanced the EM drive to the resolution of 1 uN of force. Which means, the restoring force must be < 1 uN. I would agree that IF there were a bearing with a restoring force, then to persist in the displaced position would require a continuous force. But given that it was simply a knife edge, there is nothing but gravity to restore the displacement back to the origin.

A good control test would've been to displace the EM drive to this level of displacement with the power off, and then determine how long it takes to restore the displacement back to the origin.

IMO, the correlation with temperature is a red herring. Both are slow to change and he didn't do anything to investigate if they are or are not correlated.
Todd
The knife edge itself is a means by which the balance may NOT return to its original position at all (within the very small displacements that are involved), depending on the contact forces at the knife edge, and how sharp is the knife edge.

At the knife edge you have "mountains" and "valleys" in the nanometer range.  Due to the contact force you have stresses at the peaks of these mountains that can be readily be shown are in the plastic, permanent deformation range of the elasto-plastic metal used for the knife.  Due to contact, there is a friction, due to the interweaving of contacting mountains and valleys under the contact stresses.

The force displacement (at the scale of the roughness of the knife edge) relationship is nonlinear and hysteretic (governing the contact stresses and strains of what is macroscopically known as friction): this results in stick-slip at the contact of the knife edge.  Depending on the contact load and the sharpness of the knife edge, the balance may not actually come back at all to its neutral position and may stay in the new position at a slight angle, as the restoring force due to gravity may not overcome the frictional force (due to plastic deformation of the knife edge peaks).

As you say, they should have tested this, to see whether the position is restored, how long it takes, and whether this is repeatable and uniform.

I don't get where this is going, where this "restoring force must be < 1 uN" comes from ?? A restoring force depends on a displacement, so this absolute magnitude has no meaning by itself. We can talk of restoring force given a displacement, through a certain stiffness (assuming linearity), be it a spring or around a gravitational equilibrium.

From the pictures (of limited resolution) we have and from the text we know that the knife edge balance serves to alleviate the Sartorius scale from supporting the whole weight, that doesn't mean that the knife edge balance has any meaningful "restoring force" of its own, it would be useless, it could even be slightly negative (unstable). In a serious set up, the Sartorius scale stiffness should dictates the equilibrium point displacement vs change of force on top of what's left of weight to support. Not saying that we wouldn't appreciate to see the dynamical result of a square calibration pulse of known magnitude, but really assuming that the long time-constant return time is due to some mysteriously weak restoring force is absurd, the force vs displacement is the same going from A to B as from B to A, same acceleration one way or the other, same settling times. True that some hysteresis/stiction at the dry contact of knife edge might fuzzy that linear picture a little bit, but not grossly change asymmetrically the time constants charging vs discharging.

Makes no sense to me : the Sartorius scale restores to the initial position as its spring is relieved of the added force, the balance assembly is restored to its initial position because it rests on the scale (I'm not saying it's stuck on it, doesn't need to).

Online SeeShells

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It's really not about personalities, but rather about our precious corpus of knowledge we call science. EmDrive as described violates conservation of momentum, which is linked, via Noether's symmetry theory, to the invariance of physics under displacements in space. Or in layman's terms, the electron charge is the same in Hoboken as it is in Hampstead. Everyone (with at least one notable exception and his acolyte) understands this. Therefore, if EmDrive works then it topples the entire edifice of physics. This is not a small thing, and one should expect a suitably graded response from science professionals. It's perfectly predictable.

I would have to disagree entirely. Why is it ok to assume that the Emdrive must work the way Shawyer's Theory says it does? My personally problem with your argument is that all the criticism has the built in assumption that If the EmDrive works Shawyer's theory must be right. When it could also be possible that If the EmDrive works Shawyer's theory cannot completely be used to explain it. I suspect that at best his thrust scaling predictions will be a good approximation.
I do believe that you've misunderstood me, Sir.

What I said in no way reflects upon Shawyer's theory or lack thereof. It's a general comment about how a mainstream professional scientist, accustomed to making media pronouncements and well-known to the media, would be expected to react. Really, there are no surprises here. He's almost duty bound to call it crap.

If I were outraged by this and wished to mount a counter-argument, I would not go the well-trodden route taken by the fringe and the ignorami by portraying scientists as white lab-coated mandarins floating about in their expensive laboratories clutching clipboards, condescending to everybody, and dishing out pronouncements like stone tablets.

Instead, I'd simply quote Feynman (if I could find the quote  :-[) where he talks about Mother Nature as the Mistress of all science, and that at the end of the day, since all we can learn is Her data, all we have is that data, and we must perforce follow that data. If our theory contradicts the data, and we have triple-checked the integrity of our data-taking, then it's our theory that has to go, because the data is the boss.

Offline rfmwguy

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Shop 35.2 C...no thermal runs for NSF-1701 tonight :(

Offline deltaMass

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Makes no sense to me : the Sartorius scale restores to the initial position as its spring is relieved of the added force, the balance assembly is restored to its initial position because it rests on the scale (I'm not saying it's stuck on it, doesn't need to).
Good grief - how did I miss this? (come to think of it, how did many of us?). Yes, of course you must be right - the knife edge is simply a static offset so that changes in weight can be measured in an object which is too heavy to sit on the measuring scale without such  leverage.

Offline Rodal

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@Rodal
1.Thanks for verification (picture Tajmar device yesterday @4,556GHz).
My calculation was verry close :)

2. impressing picture of the fractal antennas... like that
But for what is that good in the frustrum? This type of antenna will be use to get large bandwide, for multiband mobilephones for example. We don't need large BW.
What is need is ~constand impedance match in the possible drift BW if a high Q is recommend like discussed before?
 
3.
"3) We also verified that one cannot excite Transverse Electric (TE) modes with a dipole antenna, regardless of orientation or placement in the truncated cone, the mode excited by a dipole antenna is a Transverse Magnetic (TM) mode."

At the center it doesn't work.

I remember that is possible to get TE resonance with a simple dipole:
(rfmwguy posted something similar / plans for his frustrum...)
 It's most simple for TE01p. At this mode there are currents in Phi vector inside the metallic endplate, the strongest at the radius who the besselfunktion is maximal.
Place a dipole at this radius close to the plate, E-field vector in Phi direction(tangetial to the radius).
The result will be the correct mode if the cone has the correct length to catch that eigenfrequence.

Something similar is possible at the sidewall, one have to activate currents in the right direction for the mode in the wall..
of course one need a full 3D model

very interesting posts today too much to read all after long day full of work  :-[

Very nice post X_Ray.  I was thinking of potentially using a 1/10 wave loop (like the square one I posted as it could be modeled) to excite a TE mode center in either center plate. The bandwidth should be around 20-30 mhz. Thoughts?

Also won't a loop on the side wall excite either mode depending on orientation?

Would love your feedback.

Shell

garbage wording.
Can you repost a link to your setup please?
I'm a little tired today, don't wanna search...
I think up to a quater wavelength will work like you want without bigger problems.
couple the end of the loop direct to the copper( matching capacitor will also work between loops end and copper).
Dipoles very close to the wall will work also.
Picture:
In general,pace the antenna in one of the positions like in the sketch.

Yang/Shell natural frequency = 2.456 GHz for TE012 (compared to 2.494 GHz for TM113)

using

epsilon0 = 8.854187817*10^(-12)
mu0 =  0.999991(*copper*)*4*Pi*10^-7)
resistivity =  1.678*10^(-8)(*pure copper*)

Theoretical Q = 68,705 for TE012 (compared to Q  = 45,039. for TM113)
same material properties: TE012 has significantly higher Q than TM113

Difference in Q is due entirely to the electromagnetic field distribution


for other materials or impure copper scale Q by the Square Root of the ratio of the actual resistivity to 1.678*10^(-8)

I attach below:

1) TE012 Yang/Shell Contour Plot of Electric Field in Azimuthal (Circumferential) direction in the flat plane with trapezium boundaries

2)  TE012 Yang/Shell Magnetic Vector Field in the flat plane with trapezium boundaries

3)  TE012 Yang/Shell Electric Vector Field in the circular cross-section at spherical radius r=0.88 m

4)  TE012 Yang/Shell Magnetic Vector Field in the circular cross-section at spherical radius r=0.88 m

CONCLUSIONS:

1) based on the actual magnitude and directions of the electromagnetic fields in the TE012 mode it does not look that easy to excite TE012 using a dipole antenna.

2) it looks like it would be much easier to excite TE012 by using a loop antenna (it could be a square loop)
« Last Edit: 07/30/2015 02:35 AM by Rodal »

Online SeeShells

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Dr. Rodal,

Are these from the antenna positions with the monopole in the side towards the bottom exciting the TE mode I sent you and aero?

Shell

Edit: I'd like to see a square loop (sounds weird) antenna if it could be modeled. What happened to our meep crew? They rocked and poofed.

This was a monopole antenna not a dipole set into the sidewall, a dipole wouldn't do TE modes. Just used the sidewall of the cavity as a ground plane.
« Last Edit: 07/30/2015 12:57 AM by SeeShells »

Offline Rodal

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Dr. Rodal,

Are these from the antenna positions with the monopole in the side towards the bottom exciting the TE mode I sent you and aero?

Shell
No.  These are the steady-state fields computed from the exact solution for the Yang/Shell cavity due purely to standing waves, assuming that (by whatever means) a pure TE012 mode has been excited

The purpose of showing these images, as per the sketch of X-Ray is : once you know what TE012 is supposed to look like for Yang/Shell, then optimize the location of the antenna to excite such a mode.

_________
PS: I did  not receive antenna positions with a monopole, rather I understand that you sent that information to aero through a private e-mail (that's what I understand from your Personal Message).   :)

Online SeeShells

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Dr. Rodal,

Are these from the antenna positions with the monopole in the side towards the bottom exciting the TE mode I sent you and aero?

Shell
No.  These are the steady-state fields computed from the exact solution for the Yang/Shell cavity due purely to standing waves, assuming that (by whatever means) a pure TE012 mode has been excited

The purpose of showing these images, as per the sketch of X-Ray is : once you know what TE012 is supposed to look like for Yang/Shell, then optimize the location of the antenna to excite such a mode.

_________
PS: I did  not receive antenna positions with a monopole, rather I understand that you sent that information to aero through a private e-mail (that's what I understand from your Personal Message).   :)
I sent pictures and a very basic calculation so it could be understood, PM here doesn't allow pics. Have aero send you or me if you want.

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