Author Topic: EM Drive Developments Thread 1  (Read 763691 times)

Offline Hanelyp

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Re: EM Drive Developments
« Reply #300 on: 08/12/2014 05:11 PM »

The forces inside a resonant chamber should be balanced, except for the feed point.  The transmission cable connecting the resonant chamber to the microwave generator is carrying momentum along with the energy.  If there's a poor match between feed line and resonator, photons bouncing back and forth may carry momentum far in excess of a single transfer of the energy.  This can be a problem for experimental integrity if the microwave generator is not on the force balance.
The null test should have also had similar error?
Not if the dummy load presented a greatly different impedance than the active resonator.

Offline Star One

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Re: EM Drive Developments
« Reply #301 on: 08/12/2014 07:42 PM »
Reading around in various places there seems to be quite a bit of growing support for thinking the Mach effect is at work here and at the same time Dr White's explanation seems to be under be a good deal of scrutiny of close scrutiny.
« Last Edit: 08/12/2014 07:42 PM by Star One »

Offline GregA

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Re: EM Drive Developments
« Reply #302 on: 08/12/2014 09:42 PM »

Not if the dummy load presented a greatly different impedance than the active resonator.
Okay, at least I understand your thinking - that there was an error in measurement, and the control for it probably didn't work.

Offline peter-b

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Re: EM Drive Developments
« Reply #303 on: 08/12/2014 09:49 PM »
The EMDrive folks approached my friends in the propulsion group at SSC about doing some experiments in the SSC propulsion lab. The EMDrive people refused to allow their drive to be tested using SSC's extremely sensitive laser thrust balance, and as a result the group told them to go elsewhere.

I've spoken a few of the propulsion group about the latest results: the consensus is poor methodology and/or experimental error.
Research Scientist (Sensors), Sharp Laboratories of Europe, UK

Offline aceshigh

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Re: EM Drive Developments
« Reply #304 on: 08/12/2014 09:51 PM »
Reading around in various places there seems to be quite a bit of growing support for thinking the Mach effect is at work here and at the same time Dr White's explanation seems to be under be a good deal of scrutiny of close scrutiny.

links to these discussions would be welcome :)

Offline Robotbeat

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Re: EM Drive Developments
« Reply #305 on: 08/12/2014 10:16 PM »
Judging from the comments here, people don't seem to have much respect for just how HARD it is to get a truly solid result from a small signal and just how EASY it is to fool oneself. This is why we make scientists go to grad school and do real research. Getting VALID results from noisy data is a Herculean task, and at every single step, there's a temptation to interpret your noisy data as confirming your expectations or to remove "outliers" that can subtly tilt the odds in favor of your desired outcome. No outright fraud is necessary for this to happen! That's a common mistake that non-scientists make: if someone gets a false positive, it must be because of intentional fraud, the naive may say. But no, it's much subtler than that. Teasing out signals in noisy data is so easy to screw up. An enormous amount of self-skepticism is necessary or you will produce non-reproducible results (which are ultimately shown to be in error).

Or, in the words of Richard Feynman, "The first principle is that you must not fool yourself, and you are the easiest person to fool!"

Nature does not give up her secrets easily, and she doesn't care how much you want a certain thing to be true.


I would literally cut my arm off if doing so would make these results valid. But chances are, it's just a false positive. From a Bayesian perspective, because conservation of momentum and energy are so well established (and ways to keep conservation with these results equally unlikely), even a positive, "statistically significant" result (p<0.05) WITHOUT systematic error would almost certainly still be a false positive, by an enormous margin.
« Last Edit: 08/12/2014 10:22 PM by Robotbeat »
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Offline Robotbeat

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Re: EM Drive Developments
« Reply #306 on: 08/12/2014 10:44 PM »
In undergrad: "Huh, didn't work as I thought it would! What did I do wrong?..."
In grad school:"Huh, this result actually confirms my hypothesis! What did I do wrong?..."
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline Star One

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Re: EM Drive Developments
« Reply #307 on: 08/12/2014 11:49 PM »
Reading around in various places there seems to be quite a bit of growing support for thinking the Mach effect is at work here and at the same time Dr White's explanation seems to be under be a good deal of scrutiny of close scrutiny.

links to these discussions would be welcome :)

Unfortunately quite a bit is on the Polywell forum & I am unsure about linking to that now as it heavily features what appears to be a banned member from here?
« Last Edit: 08/12/2014 11:50 PM by Star One »

Offline aero

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Re: EM Drive Developments
« Reply #308 on: 08/13/2014 12:29 AM »
Perhaps a different view is that on that forum there is a member loudly promoting his/her long held favorite theory. As he has been for a long time, loudly and often. He has won over a few converts.

I've no opinion about ME theory or the Woodward effect but I wouldn't promote it as "One size fits all." Neither would I say that there is no chance of it fitting as no one really knows.
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Offline GregA

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Re: EM Drive Developments
« Reply #309 on: 08/13/2014 01:02 AM »
Can anyone shed some light on the Chinese research done a couple of years ago, finding a greater effect, and flaws in that?

Offline aero

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Re: EM Drive Developments
« Reply #310 on: 08/13/2014 01:46 AM »
Can anyone shed some light on the Chinese research done a couple of years ago, finding a greater effect, and flaws in that?

A professional English translation of the paper Net thrust measurement of propellantless microwave thrusters*.

http://www.emdrive.com/yang-juan-paper-2012.pdf
« Last Edit: 08/13/2014 01:50 AM by aero »
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Offline cuddihy

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Re: EM Drive Developments
« Reply #311 on: 08/13/2014 03:23 AM »

I would literally cut my arm off if doing so would make these results valid. But chances are, it's just a false positive. From a Bayesian perspective, because conservation of momentum and energy are so well established (and ways to keep conservation with these results equally unlikely), even a positive, "statistically significant" result (p<0.05) WITHOUT systematic error would almost certainly still be a false positive, by an enormous margin.

A third possibility (remote but more likely than violation of conservation of mass/momentum) is that of a non-confirming true positive -- that is a result that is not due to some kind of error in experiment but that is attributable to something (new) other than the tested theory. This is what those speculating on unintended Woodward effect as the cause of the thrust are pushing. It offers a (sounder) theoretical basis for "propellantless" thrust that does not require facial violation of established physics, only the swallowing of incredible results.

Another example of this type of possibility would be a never-before-observed directional coupling mechanism between the vacuum chamber and the feed lines... Some experiment failures are interesting in their own right.

Offline Star One

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Re: EM Drive Developments
« Reply #312 on: 08/13/2014 06:28 AM »
Perhaps a different view is that on that forum there is a member loudly promoting his/her long held favorite theory. As he has been for a long time, loudly and often. He has won over a few converts.

I've no opinion about ME theory or the Woodward effect but I wouldn't promote it as "One size fits all." Neither would I say that there is no chance of it fitting as no one really knows.

Thanks that's probably not a bad way of putting it on second thoughts. I don't know this person's history but it certainly seems a rather dominant poster on there.
« Last Edit: 08/13/2014 10:09 AM by Star One »

Offline Stormbringer

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Re: EM Drive Developments
« Reply #313 on: 08/13/2014 07:25 AM »
well if  the ME idea turns out to be valid there might be an Ansible in it for free. :)

of course accepting the ME idea there are several proposed mechanisms by which it could work. but if the ME is valid and it turns out to involve Freeman's advanced and retarded wave explanation then because inertia would be a result of communication with distal parts of the universe then you should be able to modulate an ME device output and send encoded information.
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Offline Star One

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Re: EM Drive Developments
« Reply #314 on: 08/13/2014 10:11 AM »
well if  the ME idea turns out to be valid there might be an Ansible in it for free. :)

of course accepting the ME idea there are several proposed mechanisms by which it could work. but if the ME is valid and it turns out to involve Freeman's advanced and retarded wave explanation then because inertia would be a result of communication with distal parts of the universe then you should be able to modulate an ME device output and send encoded information.

I am not sure that's a very good idea to send out info to who knows what & where.:)

http://news.bbc.co.uk/1/hi/8642558.stm
« Last Edit: 08/13/2014 10:15 AM by Star One »

Offline frobnicat

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Re: EM Drive Developments
« Reply #315 on: 08/13/2014 10:59 AM »
Another example of this type of possibility would be a never-before-observed directional coupling mechanism between the vacuum chamber and the feed lines... Some experiment failures are interesting in their own right.

Making a fully rotationally symmetric apparatus would eliminate a whole range of possible failure modes : vertical cylindrical vacuum chamber with co-axial axis of rotation for the horizontal balance beam, thruster resonant cavity mounted on one end of the beam and counter weight at the other end (or better yet another identical fed resonant cavity). Ideally waveguide(s) injecting RF power and measuring reflecting waves also co-axial (cylindrical inlet freely rotating inside fixed feed line, with 0 friction small gap<<wavelength between). Any displacement would leave the whole moving system in an equivalent geometric situation relative to vacuum chamber frame of reference. Remaining failure modes, if apparent thrust is observed, would imply momentum transfers "transverse" from reference frame surfaces : my guess it's not impossible but much weaker effects that pushing orthogonally with pressures/varying volumes, assuming leaks or feed lines couplings (fields in varying volumes between moving parts and fixed parts).

For levels of power/thrust ratios of the order reported by the Chines experiment or R. Shawyer it should even be relatively easy to have a freely rotating beam with residual torque resistance much below the torque given by such net thrust. Let it accelerate and observe the thrust relative to speed...

One question : what is the difference between a cavity that is fed at its resonant frequency and a cavity that is fed with a different frequency, at same power levels ? My maybe incorrect understanding is that when resonance is present the different waves bouncing back and forth happen to "synchronize" in a standing wave where anti-nodes exhibit amplitudes Q (quality factor) times stronger than the incoming excitation. But from a photon point of view, you are just throwing photons in a cavity and the collective behaviour is just the sum of individual behaviours : whatever frequency (in a wide range) the photons will bounce back and forth on the order of Q times before being absorbed (dissipated) on walls, regardless of resonance or not. So for a given power input and given Q, EM energy density is the same, resonance or not, only the amplitudes don't sum up well when not resonant, please tell if wrong. My point is, if thrust effect is real it can't be about just classical linear EM waves bouncing back and forth in asymmetrical cavity : resonance wouldn't change the effect, while all of the proponents seem to imply resonance is central with their experiments.

Maxwell equations are linear, same with the ohmic losses (at skin depth in the cavity's walls). Specifically resonance would be necessary to reach fields strong enough to enter nonlinear effects ranges ? How the reached resonant amplitudes compares with known limits of linearity, dielectric strength for instance ?

Thank Aero for the link to english translation of the Chinese paper.

Offline aceshigh

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Re: EM Drive Developments
« Reply #316 on: 08/14/2014 06:02 AM »
Perhaps a different view is that on that forum there is a member loudly promoting his/her long held favorite theory. As he has been for a long time, loudly and often. He has won over a few converts.

I've no opinion about ME theory or the Woodward effect but I wouldn't promote it as "One size fits all." Neither would I say that there is no chance of it fitting as no one really knows.

Thanks that's probably not a bad way of putting it on second thoughts. I don't know this person's history but it certainly seems a rather dominant poster on there.

he is not a dominant poster, and he fought with many forumers there. BUT we should not judge his ideas by his personality.

plenty of forumers there ARE on Woodwards emailing list.


Also bear in mind there is a long long Mach Effect thread on that forum, where Paul March (who works with Dr White) and is known here on NSF as Stardrive) had many posts and long discussions.


93143 can talk about the situation too, since he is also a long time poster at Talk Polywell and here at NSF.

Offline Stormbringer

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Re: EM Drive Developments
« Reply #317 on: 08/14/2014 07:00 AM »
hey, there is a new article at new scientist on CERN's hunt for monopoles. i am not a subscriber so i cannot access the full article. but if they find monopoles and can reproduce them in large numbers you could see materials that won't melt if you dunk them into a star or detonate a nuke on top of it. probably good stuff for rocket nozzles and high temperature and pressure reactor parts. even before that though exo-thermal reactions between monopole atoms would pack the power of a nuclear reaction in normal matter. if there were transparent monopole substances/elements (for example; monopole versions of silicon or quartz) you could have a window that is unbreakable even with relativistic impacts.
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Offline Star One

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Re: EM Drive Developments
« Reply #318 on: 08/14/2014 09:22 AM »
Perhaps a different view is that on that forum there is a member loudly promoting his/her long held favorite theory. As he has been for a long time, loudly and often. He has won over a few converts.

I've no opinion about ME theory or the Woodward effect but I wouldn't promote it as "One size fits all." Neither would I say that there is no chance of it fitting as no one really knows.

Thanks that's probably not a bad way of putting it on second thoughts. I don't know this person's history but it certainly seems a rather dominant poster on there.

he is not a dominant poster, and he fought with many forumers there. BUT we should not judge his ideas by his personality.

plenty of forumers there ARE on Woodwards emailing list.


Also bear in mind there is a long long Mach Effect thread on that forum, where Paul March (who works with Dr White) and is known here on NSF as Stardrive) had many posts and long discussions.


93143 can talk about the situation too, since he is also a long time poster at Talk Polywell and here at NSF.

I meant dominant in the sense of being very active, poor choice of phrase perhaps by me.

Monopoles article as mentioned above.

http://www.newscientist.com/article/mg22329820.600-pole-alone-the-quest-for-a-north-without-a-south.html

I am subscriber but because of the paywall I cannot post the rest of it.
« Last Edit: 08/14/2014 09:34 AM by Star One »

Offline sghill

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Re: EM Drive Developments
« Reply #319 on: 08/14/2014 04:21 PM »
well if  the ME idea turns out to be valid there might be an Ansible in it for free. :)

of course accepting the ME idea there are several proposed mechanisms by which it could work. but if the ME is valid and it turns out to involve Freeman's advanced and retarded wave explanation then because inertia would be a result of communication with distal parts of the universe then you should be able to modulate an ME device output and send encoded information.

I am not sure that's a very good idea to send out info to who knows what & where.:)

http://news.bbc.co.uk/1/hi/8642558.stm

That Ansible would help explain the Fermi Paradox! 

I have a general magnetism question that this thread has made pop into my mind.  How can magnets attract or repel each other indefinitely without expending energy? If I put two ring magnets on a pole with the same pole facing each other, the magnet on the top will float above the magnet on the bottom, the repulsive force overcoming gravity, and the equilibrium distance between the two is determined by the field strength of the magnets. All that is well and good, but how does this happen without the repulsive (or attractive) effect fading over time and the magnets getting warm or otherwise emitting photons?  In other words, the floating magnet is continually resisting an accelerative force due to gravity, so it (and the other magnet) has to expend energy to counter gravity for it to stay afloat.  So where does that continual input energy come from? Even if it's at the nuclear level, there has to be an expenditure somewhere in order to negate gravitational acceleration.
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