Author Topic: EM Drive Developments Thread 1  (Read 762540 times)

Offline pagheca

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Re: EM Drive Developments
« Reply #140 on: 08/03/2014 07:01 AM »
I wouldn't dream of posting here....
I can understand the skepticism...
However the experimenters are all NASA scientists.
What is the problem? are you a better scientist John F? Or do you think the authors should be stripped of their NASA posts?
Maybe we should calm down and investigate further?
Heavens!

The problem is that the article linked is not a scientific paper, but a clearly preliminary technical report, the typical "hat on the seat" (copyrighted by me :) ) paper required to ensure to be the first IF a sensational result is confirmed in order to get an high citation index in the future.

(1) There has been no submission to refereed journals as for the standard scientific procedure.

(2) No details about the experimental setup have been given. So, it is impossible to submit the paper to a check, or to repeat the experiment to check for eventual involuntary errors by the scientists.

(3) there is the detail of thrust measured also in the "null" test article, that was unexpected and suggest there is a bias somewhere in the measuring system.

I would suspend any judgement till a proper paper is submitted to a proper journal. However, let me remind that extraordinary claims require extraordinary evidences, that is not the case here.

p.s. I had no time to read all the thread. So, apologies if there are other papers confirming the results. I refer just to one linked at the beginning of the thread, that is also the one linked to the digitaltrend article.
« Last Edit: 08/03/2014 11:33 PM by pagheca »

Offline Silversheep2011

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Re: EM Drive Developments
« Reply #141 on: 08/03/2014 07:22 AM »

This discovery came about because Shawyer was trying to explain the thrust generated by the microwave transmitters on satellites which exceeded what was expected and required additional fuel to correct.

This would really make an interesting subject to read or a comparison point to read up on.
who you be able to supply a link or a paper?

Offline john smith 19

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Re: EM Drive Developments
« Reply #142 on: 08/03/2014 07:41 AM »
OK, here's an idea. The resonant cavity's purpose is to produce standing waves, right? So, basically it's a precise arrangement of conducting plates which reflect EM waves back and forth. For some reason, this reminds me of a "macro" Casimir cavity, just on a different scale and with "real" photons. So, what if.. this EM drive acted (by coincidence) as some weird form of "macro" Casimir cavity and its specific shape (accidentally) produced a preferred vector, working with real photons? I seem to remember that specific geometries of Casimir cavities were calculated to be able to produce a preferred vector of motion. I didn't find that piece of info yet again, or perhaps I remember wrongly. Maybe someone else knows better?
I'd say it's doubtful. It's about the lifetime of the  virtual particle before it cease to exist. AFAIK it's short, so they don't go very far before they disappear.

That said there is an interesting analogy. "Temperature" is a measure of a particles velocity, but if the particles are a gas they move in random directions stopped only by their collisions with the container walls or other particles. If you could filter the particles by velocity you would have a way to separate a gas at say room temperature into 2 streams, one quite a bit hotter, one quite a bit colder than room temperature.

Which sounds crazy.

Except the device is called a Ranque-Hilsch or vortex tube and has existed for about 70 years.

http://en.wikipedia.org/wiki/Vortex_tube

[WARNING Rampant speculation ]
If some sort of separation effect is happening with virtual particles (or could be made to) that might explain some thrust measurements.
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Offline CW

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Re: EM Drive Developments
« Reply #143 on: 08/03/2014 08:03 AM »
Considering that both test articles (null and 'real') seemed to produce some measurable thrust (systematic errors excluded), I have the impression that the scientists involved might be victims of the principle of logical implication, which states that from a wrong premise anything can follow, even the correct solution or answer. It would be interesting and very lucky, if they had stumbled upon some new principle by accident, starting from a physically incorrect premise or train of thought. In no case do I think that conservation of momentum can be broken. If real, there must be some form of opposite momentum occurring - in whatever unusual way yet to be observed.
« Last Edit: 08/03/2014 08:05 AM by CW »
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Offline QuantumG

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Re: EM Drive Developments
« Reply #144 on: 08/03/2014 08:29 AM »
Why are there now two threads for this nonsense?
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Offline francesco nicoli

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Re: EM Drive Developments
« Reply #145 on: 08/03/2014 08:38 AM »
I have no idea whether such a device could work. I see the consensus among physicists is that there should be some unobserved thing which simulates the effect. I believe that is mostly likely.
However, these guys are still nasa scientists, not exactly any Rossi whatsoever. Many of them have doctoral degrees and they are preparing a peer-review publication. So let's wait and see where and whether they made a mistake. As a scientist (albeit in a different discipline) I recognize here the holy fire of curiosity....
« Last Edit: 08/03/2014 08:39 AM by francesco nicoli »

Offline CW

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Re: EM Drive Developments
« Reply #146 on: 08/03/2014 09:20 AM »


I was mainly looking for a short description of a major issue with the experiment that I can feed to people to prompt them to engage their brains for a minute rather than shoveling the bull**** down their throats without thinking. After that some discussion can be sparked to realize the issues at hand.

i think there are two major issues.

1. the signal is very small. this makes it easy for uncontrolled for unanticipated spurious signals to get in there. critic can claim this is what caused it all day long. it's hard to disprove.

2. in this experiment it appears the control test article got the same signal. I do not think this is as damning as it could be because of the signals found by other researchers with (similar devices of differing design details.)  E.G. Dr Woodward's design is a solid state peizoelectric stack. he gets a thrust signal. Dr White has a capacitor and coil ring and gets thrust signals. the Egyptian girl uses a moving casimir mirror and gets a thrust signal. The Chinese use Shayer's design as a starting point and get a much stronger thrust signal than he did or NASA testing got.

I think that what could bring this whole thing forward is to ask, what do all these experimental devices have in common that leads to a measured thrust - as different as they may seem. It could be a systematic error, but it would in turn also be an interesting insight if each and every one group doing these experiments made the same systematic errors. It seems possible, but the less likely, the more groups are independently letting the results get peer-reviewed. I'm looking forward to any kind of result.
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Offline CharlieWildman

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Re: EM Drive Developments
« Reply #147 on: 08/03/2014 03:17 PM »
Looking at the very small amount of thrust generated I suspect measurement error or a problem with how the testing was set up.

Correct me if I have this wrong but 30 to 50 micro Newtons of thrust (.000030 to .000050 Newton)  equates to about . .003 to .005 grams of thrust.

This tiny amount of force could easily be generated by air currents around what must be a warm to hot test article and could explain why the 'null' test article also produced thrust.

According to the NASA document http://ntrs.nasa.gov/search.jsp?R=20140006052 all testing was done in a vacuum chamber  'at ambient atmospheric pressure'.

I sure hope I'm wrong!!!   


Charlie


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Offline mlindner

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Re: EM Drive Developments
« Reply #148 on: 08/03/2014 05:29 PM »
They are made by not having any preconceived ideas about applications.

How do you look for a new law in physics?

A friend shared this with me. It makes the point well.
and Visa versa



It disagrees with experiment. So its wrong.
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Offline hop

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Re: EM Drive Developments
« Reply #149 on: 08/03/2014 07:42 PM »
The problem is that the article linked is not a scientific paper, but a clearly preliminary technical report, the typical "hat on the seat" (copyrighted by me :) ) paper required to ensure to be the first IF a sensational result is confirmed in order to get an high citation index in the future.
A link to the actual paper may be found at
https://plus.google.com/117663015413546257905/posts/C7vx2G85kr4

However this is a conference paper, which in many cases aren't peer reviewed in the same way a journal paper would be. I'm not sure about this particular case.

In any case, if Baez summery is correct, there is really nothing worth talking about here... (which should be no surprise to anyone who read the original abstract)
« Last Edit: 08/03/2014 07:42 PM by hop »

Offline Star One

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Re: EM Drive Developments
« Reply #150 on: 08/03/2014 07:47 PM »
It seems much confusion has arisen here. I have been reading on the Polywell forums that firstly the business with the Null article is not a concern, what you are seeing is an ill chosen abstract by NASA. Please see the quote below for more detail. Secondly, Eagle Works are currently building a suitable test article that will be shipped around to any lab that cares to test it according to further posts on there. They are also building a higher power device again according to posts on there.

Quote
No, the NASA folks shot themselves in the foot with this unclear NTRS abstract, which is very misleading once you have read the complete paper, as birchoff and I did. Birchoff is right, the paper is only $25, and now it's very clear that even ArsTechnica only read the NTRS abstract and didn't download the complete paper before writing and publishing their biased article. Very poor journalism.

The fact is (and the NTRS abstract does not explain this): Eagleworks tested one tapered (frustum) cavity, aka Shawyer's EmDrive; and two Cannae drives which are also asymmetric but different resonant cavities. The Cannae drive is said to work on a purported different principle than the EmDrive, according to its inventor Guido Fetta (a net Lorentz force imbalance of electrons upon top vs bottom wall of the cavity). According to this purported working principle, one Cannae drive had radial slots on its rim as required by Fetta in order to produce net thrust, and the second Cannae drive didn't have those slits and was intended to be a "null test device". But the Cannae null test article… also produced net thrust (20 to 40 µN of net thrust depending of the forward or backward direction).

We're talking of net thrust because of course the setup was also tested with a null 50 ohm load connected, in order to cancel the effect from the drives and detect any detect any spurious force due to EM coupling with the whole apparatus (which exists, at 9.6 µN) and this "null" spurious force was evidently subtracted from any thrust signal due to the drives then tested on the pendulum.

So the fact that the Cannae null test article produced a net thrust doesn't imply the experiment was screwed up. It rather showed that the radial slits required by Guido Fetta for propulsion are not the reason for the thrust, and another theoretical explanation is needed. Absolutely no news on the websites, including wikipedia, actually reports correctly this information.

We can go further by pointing another underestimated yet important fact of those NASA experiments: all tests articles (the EmDrive version, the Cannae drive version, and even the Cannae "null test" version) had a dielectric embedded within. This is a hint for a different theoretical explanation involving EM fields, proper acceleration, mass fluctuation and dielectrics. Maybe Mach effects (due to Mach's principle), as supposed by Woodward and Fearn within the GR theory, or within a scalar-tensor theory of gravity according to Minotti. As for Sonny White, he talks about compressible quantum vacuum fluctuations, but there are flaws about this conjecture regarding the thrust magnitude observed.

http://www.talk-polywell.org/bb/viewtopic.php?f=10&t=2949&start=135#p114590
« Last Edit: 08/03/2014 07:54 PM by Star One »

Offline Star One

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Re: EM Drive Developments
« Reply #151 on: 08/03/2014 08:04 PM »


This discovery came about because Shawyer was trying to explain the thrust generated by the microwave transmitters on satellites which exceeded what was expected and required additional fuel to correct.

This would really make an interesting subject to read or a comparison point to read up on.
who you be able to supply a link or a paper?

I second that as I had wondered precisely how anyone even thought to look into this.

Offline hop

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Re: EM Drive Developments
« Reply #152 on: 08/03/2014 08:19 PM »
It seems much confusion has arisen here. I have been reading on the Polywell forums that firstly the business with the Null article is not a concern, what you are seeing is an ill chosen abstract. Please see the quote below for more detail.
If the experiments were actually done at atmospheric pressure none of that matters. It's clear from the paper that at least some of the tests were (see fig 22). That fact that it isn't clearly stated for each test is a major flaw in the paper regardless of the results, and strongly suggests the paper wasn't rigerously reviewed.

I don't understand why you think the quoted post would "clear up confusion", it looks like a hand wavy rationalization to me. To most scientists, a "null" that produces the predicted effect would be a strong hint to look for experimental error, not new physics.

Offline Stormbringer

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Re: EM Drive Developments
« Reply #153 on: 08/03/2014 08:24 PM »
Looking at the very small amount of thrust generated I suspect measurement error or a problem with how the testing was set up.

Correct me if I have this wrong but 30 to 50 micro Newtons of thrust (.000030 to .000050 Newton)  equates to about . .003 to .005 grams of thrust.

This tiny amount of force could easily be generated by air currents around what must be a warm to hot test article and could explain why the 'null' test article also produced thrust.

According to the NASA document http://ntrs.nasa.gov/search.jsp?R=20140006052 all testing was done in a vacuum chamber  'at ambient atmospheric pressure'.

I sure hope I'm wrong!!!   


Charlie

the chinese claim a much bigger thrust signal using a device evolved from Shayer's original design.

http://nextbigfuture.com/2014/07/renewed-hope-for-emdrive-with-nasa.html

Quote
Last year a Chinese team built its own EmDrive and confirmed that it produced 720 mN (about 72 grams) of thrust, enough for a practical satellite thruster. Such a thruster could be powered by solar electricity, eliminating the need for the supply of propellant that occupies up to half the launch mass of many satellites. The Chinese work attracted little attention; it seems that nobody in the West believed in it.
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Offline Star One

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Re: EM Drive Developments
« Reply #154 on: 08/03/2014 08:41 PM »
It seems much confusion has arisen here. I have been reading on the Polywell forums that firstly the business with the Null article is not a concern, what you are seeing is an ill chosen abstract. Please see the quote below for more detail.
If the experiments were actually done at atmospheric pressure none of that matters. It's clear from the paper that at least some of the tests were (see fig 22). That fact that it isn't clearly stated for each test is a major flaw in the paper regardless of the results, and strongly suggests the paper wasn't rigerously reviewed.

I don't understand why you think the quoted post would "clear up confusion", it looks like a hand wavy rationalization to me. To most scientists, a "null" that produces the predicted effect would be a strong hint to look for experimental error, not new physics.

My overall view is this is going to have wait for the further round of tests in the fall of this year, it looks like at this time there are just too many possible issues with this as it stands. It sounds like what they are planning next is either going to make or break this whole thing, at least that way it will not drag for twenty-five years as cold fusion has done.
« Last Edit: 08/03/2014 08:47 PM by Star One »

Online ChrisWilson68

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Re: EM Drive Developments
« Reply #155 on: 08/03/2014 08:48 PM »
It seems much confusion has arisen here. I have been reading on the Polywell forums that firstly the business with the Null article is not a concern, what you are seeing is an ill chosen abstract. Please see the quote below for more detail.
If the experiments were actually done at atmospheric pressure none of that matters. It's clear from the paper that at least some of the tests were (see fig 22). That fact that it isn't clearly stated for each test is a major flaw in the paper regardless of the results, and strongly suggests the paper wasn't rigerously reviewed.

I don't understand why you think the quoted post would "clear up confusion", it looks like a hand wavy rationalization to me. To most scientists, a "null" that produces the predicted effect would be a strong hint to look for experimental error, not new physics.

My overall view is this is going to have wait for the further round of tests in the fall of this year, it looks like at this time there are just too many possible issues with this as it stands. It sounds like what they are planning next is either going to make or break this whole thing.

Nothing will ever break it.  The tests will fail to show convincing evidence of anomalous thrust, and the proponents of the various reactionless drives will come up with rationalizations for it and explain how they're working on new versions that will fix the problems.  It will continue without end.

Offline Star One

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Re: EM Drive Developments
« Reply #156 on: 08/03/2014 08:55 PM »

It seems much confusion has arisen here. I have been reading on the Polywell forums that firstly the business with the Null article is not a concern, what you are seeing is an ill chosen abstract. Please see the quote below for more detail.
If the experiments were actually done at atmospheric pressure none of that matters. It's clear from the paper that at least some of the tests were (see fig 22). That fact that it isn't clearly stated for each test is a major flaw in the paper regardless of the results, and strongly suggests the paper wasn't rigerously reviewed.

I don't understand why you think the quoted post would "clear up confusion", it looks like a hand wavy rationalization to me. To most scientists, a "null" that produces the predicted effect would be a strong hint to look for experimental error, not new physics.

My overall view is this is going to have wait for the further round of tests in the fall of this year, it looks like at this time there are just too many possible issues with this as it stands. It sounds like what they are planning next is either going to make or break this whole thing.

Nothing will ever break it.  The tests will fail to show convincing evidence of anomalous thrust, and the proponents of the various reactionless drives will come up with rationalizations for it and explain how they're working on new versions that will fix the problems.  It will continue without end.

No it won't if it doesn't work EagleWorks will lose interest, the only reason it's getting attention is because of their interest.

Offline Stormbringer

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Re: EM Drive Developments
« Reply #157 on: 08/03/2014 09:09 PM »
WRT the chinese thrust claim isn't that just 1280 grams away from 1 newton of Thrust?
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Offline IslandPlaya

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Re: EM Drive Developments
« Reply #158 on: 08/03/2014 09:28 PM »
Too important to be public. Military knows to release crappy results.
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Offline CW

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Re: EM Drive Developments
« Reply #159 on: 08/03/2014 09:39 PM »
It seems much confusion has arisen here. I have been reading on the Polywell forums that firstly the business with the Null article is not a concern, what you are seeing is an ill chosen abstract. Please see the quote below for more detail.
If the experiments were actually done at atmospheric pressure none of that matters. It's clear from the paper that at least some of the tests were (see fig 22). That fact that it isn't clearly stated for each test is a major flaw in the paper regardless of the results, and strongly suggests the paper wasn't rigerously reviewed.

I don't understand why you think the quoted post would "clear up confusion", it looks like a hand wavy rationalization to me. To most scientists, a "null" that produces the predicted effect would be a strong hint to look for experimental error, not new physics.

My overall view is this is going to have wait for the further round of tests in the fall of this year, it looks like at this time there are just too many possible issues with this as it stands. It sounds like what they are planning next is either going to make or break this whole thing.

Nothing will ever break it.  The tests will fail to show convincing evidence of anomalous thrust, and the proponents of the various reactionless drives will come up with rationalizations for it and explain how they're working on new versions that will fix the problems.  It will continue without end.

In case it were all the same systematic blunder made by all groups involved with similar constructs, as likely or unlikely that may seem, a null-thrust demonstration under vacuum and subsequent working out of the details of such possible blunder, would at least add to the knowledge base as to what kind of measurement setup mistake was made. But in the end, we will see the actual results later this year - they will speak for themselves. Personally, I'd prefer an interesting result showing similar thrust under vacuum of course. But it's also great, if nothing of interest is observed. I'm just a bit worried about NASA's scientific reputation here, considering that a positive result was announced already..
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