Author Topic: EM Drive Developments - related to space flight applications - Thread 5  (Read 1203057 times)

Offline OnlyMe

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"NEGATIVE experimental results are under-reported or not reported at all.  Negative results at a University (by Zellerium) is not even reported in the EM Drive wiki (  http://emdrive.wiki/Experimental_Results ), the last time that I checked.  Several experimenters that started to report their build up, stopped reporting and are practically unheard of.  At least one of the experimenters asked -in these threads- not to report the negative experimental results.

An effort has to be made to report and properly document ALL NEGATIVE results

An effort has to be made to be objective."


Certainly worth repeating. I did ask an experimenter if this could be labeled Null. Believe this is what you are referring to. I videotaped and posted 2 or 3 flight tests I considered Null before FT#2B and reconfirmed displacement changes in FT#2C, So 3 of 5 flight tests were Null on NSF-1701. I only documented the last one on the wiki page.

Didn't Zellerium say he was getting something with a frustum, null with cylindrical and that he was discontinueing as he didn't think he could finish prior to his expected graduation date, and was doing this as a senior project?

I really wish we could get a better analysis of FT 1.  Would really like to see if having the rf feed on the small base produced a null  (and since most of the heat is coming off the magnetron housing a large different between 1 and later tests would help rule out thermal currents as the source of thrust).
Zellerium is a busy boy right before graduation, so I don't think he will respond. Where I thought he left it was Null on symmetrical cavity, no time for frustum. I do not recall reading a test report but seems to me I saw some pics posted here. Hope Kurt can get back here sometime and fill us in.

Rfmwguy,

Was he the one who said he had someone who wanted to continue, as some sort of class project?

Offline rfmwguy

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"NEGATIVE experimental results are under-reported or not reported at all.  Negative results at a University (by Zellerium) is not even reported in the EM Drive wiki (  http://emdrive.wiki/Experimental_Results ), the last time that I checked.  Several experimenters that started to report their build up, stopped reporting and are practically unheard of.  At least one of the experimenters asked -in these threads- not to report the negative experimental results.

An effort has to be made to report and properly document ALL NEGATIVE results

An effort has to be made to be objective."


Certainly worth repeating. I did ask an experimenter if this could be labeled Null. Believe this is what you are referring to. I videotaped and posted 2 or 3 flight tests I considered Null before FT#2B and reconfirmed displacement changes in FT#2C, So 3 of 5 flight tests were Null on NSF-1701. I only documented the last one on the wiki page.

Didn't Zellerium say he was getting something with a frustum, null with cylindrical and that he was discontinueing as he didn't think he could finish prior to his expected graduation date, and was doing this as a senior project?

I really wish we could get a better analysis of FT 1.  Would really like to see if having the rf feed on the small base produced a null  (and since most of the heat is coming off the magnetron housing a large different between 1 and later tests would help rule out thermal currents as the source of thrust).
Zellerium is a busy boy right before graduation, so I don't think he will respond. Where I thought he left it was Null on symmetrical cavity, no time for frustum. I do not recall reading a test report but seems to me I saw some pics posted here. Hope Kurt can get back here sometime and fill us in.

Rfmwguy,

Was he the one who said he had someone who wanted to continue, as some sort of class project?
Yes, that is where he left off IIRC.

<edit> found it: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=37642.0;attach=837146
« Last Edit: 12/05/2015 02:38 pm by rfmwguy »

Offline Rodal

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"NEGATIVE experimental results are under-reported or not reported at all.  Negative results at a University (by Zellerium) is not even reported in the EM Drive wiki (  http://emdrive.wiki/Experimental_Results ), the last time that I checked.  Several experimenters that started to report their build up, stopped reporting and are practically unheard of.  At least one of the experimenters asked -in these threads- not to report the negative experimental results.

An effort has to be made to report and properly document ALL NEGATIVE results

An effort has to be made to be objective."


Certainly worth repeating. I did ask an experimenter if this could be labeled Null. Believe this is what you are referring to. I videotaped and posted 2 or 3 flight tests I considered Null before FT#2B and reconfirmed displacement changes in FT#2C, So 3 of 5 flight tests were Null on NSF-1701. I only documented the last one on the wiki page.

Didn't Zellerium say he was getting something with a frustum, null with cylindrical and that he was discontinueing as he didn't think he could finish prior to his expected graduation date, and was doing this as a senior project?

I really wish we could get a better analysis of FT 1.  Would really like to see if having the rf feed on the small base produced a null  (and since most of the heat is coming off the magnetron housing a large different between 1 and later tests would help rule out thermal currents as the source of thrust).
Zellerium is a busy boy right before graduation, so I don't think he will respond. Where I thought he left it was Null on symmetrical cavity, no time for frustum. I do not recall reading a test report but seems to me I saw some pics posted here. Hope Kurt can get back here sometime and fill us in.

Rfmwguy,

Was he the one who said he had someone who wanted to continue, as some sort of class project?
Yes, that is where he left off IIRC.

<edit> found it: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=37642.0;attach=837146

The attached link (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=37642.0;attach=837146) shows that:

Concerning the question

Quote
Didn't Zellerium say he was getting something with a frustum
,

NO, the document  does not report getting any force measurements using the frustum of a cone.  The attached document is a short document proposing measurements.  No experimental measurements with a frustrum of a cone are reported.


Essentially my recollection is identical to rfmwguy:

Quote
I thought he left it was Null on symmetrical cavity, no time for frustum.

Except that "symmetrical" is not a precise, correct, statement, because any cavity (including cavities with uniform cross-section for example circular or rectangular cross-section) containing an unsymmetrically placed dielectric are effectively unsymmetric for the purposes of electromagnetic wave propagation (as there is a power loss in the dielectric but effectively insignificant power loss in the empty section, and as the group and phase velocities are different in the dielectric section than in the empty section of the cavity).

The unsymmetry produced by an unsymmetrically placed dielectric in a cavity with uniform cross-section have been discussed by Prof. Woodward, Paul March, Notsosureofit, Mulletron and even Roger Shawyer (in his first EM Drive patent).

And as Flux_Capacitor pointed out (Bold added for emphasis):

http://forum.nasaspaceflight.com/index.php?topic=31037.msg1430962#msg1430962

Quote
Let me summarize this, as I've read what Woodward thinks about the EmDrive: he does not believe that an EmDrive without a dielectric within can work at all; and while he thinks an EmDrive with an internal electrostrictive dielectric could work because of some Mach effect, he denies the reality of any quantum vacuum plasma-based propulsion.

The negative result of Zellerium at a US University with such a cavity is important to be documented (it is still not listed in the EM Drive wiki).
« Last Edit: 12/05/2015 04:28 pm by Rodal »

Offline rfmwguy

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"NEGATIVE experimental results are under-reported or not reported at all.  Negative results at a University (by Zellerium) is not even reported in the EM Drive wiki (  http://emdrive.wiki/Experimental_Results ), the last time that I checked.  Several experimenters that started to report their build up, stopped reporting and are practically unheard of.  At least one of the experimenters asked -in these threads- not to report the negative experimental results.

An effort has to be made to report and properly document ALL NEGATIVE results

An effort has to be made to be objective."


Certainly worth repeating. I did ask an experimenter if this could be labeled Null. Believe this is what you are referring to. I videotaped and posted 2 or 3 flight tests I considered Null before FT#2B and reconfirmed displacement changes in FT#2C, So 3 of 5 flight tests were Null on NSF-1701. I only documented the last one on the wiki page.

Didn't Zellerium say he was getting something with a frustum, null with cylindrical and that he was discontinueing as he didn't think he could finish prior to his expected graduation date, and was doing this as a senior project?

I really wish we could get a better analysis of FT 1.  Would really like to see if having the rf feed on the small base produced a null  (and since most of the heat is coming off the magnetron housing a large different between 1 and later tests would help rule out thermal currents as the source of thrust).
Zellerium is a busy boy right before graduation, so I don't think he will respond. Where I thought he left it was Null on symmetrical cavity, no time for frustum. I do not recall reading a test report but seems to me I saw some pics posted here. Hope Kurt can get back here sometime and fill us in.

Rfmwguy,

Was he the one who said he had someone who wanted to continue, as some sort of class project?
Yes, that is where he left off IIRC.

<edit> found it: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=37642.0;attach=837146

The attached link (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=37642.0;attach=837146) shows that:

Concerning the question

Quote
Didn't Zellerium say he was getting something with a frustum
,

NO, the document  does not report getting any force measurements using the frustum of a cone.  The attached document is a short document proposing measurements.  No experimental measurements with a frustrum of a cone are reported.


Essentially my recollection is identical to rfmwguy:

Quote
I thought he left it was Null on symmetrical cavity, no time for frustum.

Except that "symmetrical" is not a precise, correct, statement, because any cavity (including cavities with uniform cross-section for example circular or rectangular cross-section) containing an unsymmetrically placed dielectric are effectively unsymmetric for the purposes of electromagnetic wave propagation (as there is a power loss in the dielectric but effectively insignificant power loss in the empty section, and as the group and phase velocities are different in the dielectric section than in the empty section of the cavity).

The unsymmetry produced by an unsymmetrically placed dielectric in a cavity with uniform cross-section have been discussed by Prof. Woodward, Paul March, Notsosureofit, Mulletron and even Roger Shawyer (in his first EM Drive patent).

The negative result of Zellerium with such a cavity is important to be documented (it is still not listed in the EM Drive wiki).
I've always been reluctant to update the wiki page on anyone other than my own experiment. Whats your thoughts Doc. I didn't start the wiki...

Offline ThereIWas3

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Is the results table in the wiki available somewhere as a spreadsheet or CSV file?

Offline Prunesquallor

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...

* Writing about science fiction flying cars and short-trips to Pluto (or even the Stars ! ) that violate conservation of energy by Shawyer, instead of providing new, strong experimental evidence that can be independently verified

...

are not positive

To some degree, I disagree with this. For example, for EMDrive experimentation to be within the purvue of NASA, or indeed this forum, I think it is necessary to investigate the implications to space flight.  These should be clearly stated in the form of "if this performance level, behavior, etc. could be attained, these would be the implications" along with details of the assumptions and analysis techniques, rather than unqualified promises of future benefits. You are right, Shawyer was more the latter than the former.
Retired, yet... not

Offline zen-in

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I looked at the wiki page a few times and I don't believe the data accurately shows the outcome of diy experiments.   Part of the problem is people like to "data reduce" and cherry pick data.    A more scientific method is to establish a protocol to follow for each experiment and to record everything in exacting detail as it is done in a lab notebook.    Each experimental run then has a complete paper record that can be referred to later on.  Video recording is fine but I don't think it is suitable for recording an experiment.   There are too many measurements, changes to the apparatus, etc.  that are not available in a video.    It appears the EW tests did follow this method but I don't believe they provided data on all their tests.   Another aspect of testing is repeatability.   If someone does a test they should try to set up the experiment again under the same conditions and run it again.  These would be recorded as repeats of one experiment where the protocol has not changed.   It may be necessary to allow time for everything to cool down to room temperature and to fiddle with the apparatus so it is setup the same each time.    After several runs have been done - maybe 10 - 20 then run some statistical data analysis.   What is the standard deviation of the "thrust" that was measured?   What is the mean?   Plot the results on a bar graph so the whole set of experiments can be seen.   Now change some part of the experiment and repeat.
« Last Edit: 12/05/2015 06:57 pm by zen-in »

Offline Rodal

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...
Dr. Rodal - I uploaded these progressively longer runs of the Yang-Shell 6 degree model just about the time than you went dark. I did notify you but have no indication that you received my notification, so I repeat it here. The csv data is here. Please read the data description there.

https://drive.google.com/folderview?id=0B1XizxEfB23tRm41bVFtM1pVYlU&usp=sharing

These runs range in length from 32 cycles to 2048 cycles of the drive frequency. That is not a long time, I guess something like 2048cycles/2.45 GHz, or close to a microsecond of simulated time, but something like 2 days wall clock time for each of the 2048 cycle runs.

On the other current subject, I did modify the copper conductance model after seeing the same information from you and three other sources, two of which you linked. The model code now reads as.

(material (make medium (epsilon epsilon_r) (D-conductivity CU-D-conduct)))

where epdilon_r = 1

numerical value of CU-D-conduct is: (printed from a run log file)
 CU-D-conduct = 43393352.18305066
old-CU-conduct= 4904277351.366935
 ratio of new over old = 0.008848062430840282

As I gain some meep experience in working with this new copper model, Shell will know and I'm sure data will be posted. As for now I have learned that it cuts Q a lot and Q is strongly dependent on meep resolution with this new model, not in the same way as for the older models. The other data hinted at is ... Well as I've only ran one cavity case, cylindrical at that, I should keep my suspicions under my hat until I have at least some confirmation.

And if that is not the correct numerical value as you understand it, please tell me promptly. A simple "still not right, aero" would have me double checking again though the correct numerical value would be helpful. Rest assured, I will not change the model until I satisfy myself that it needs to be changed.

Thanks, that is the correct ratio of new to old conductivity: 0.0088480= 1/113.019...

The new one should be 113.019 times lower.

Remember that this is for high-content copper, as intended by DeltaMass.

Other materials (silver, brass, gold, etc.) need to be ratioed by their corresponding conductivities (or their inverse, resistivities).

Ok, here is a very nice data set of conductivities/resistivities:
http://eddy-current.com/conductivity-of-metals-sorted-by-resistivity/
DeltaMass' conductivity number was 3.25E+8 determined from considerations of the electron cloud, as I recall. As Murphy would dictate, that number does not appear in this data list. I can search further but I think it is safe to assume that 3.25E+8 will not appear elsewhere exactly. What is the recommended way to adjust ratios to maintain consistency, or would it be less complex to simply use the meep units conversion wiki, as I did for this modification?

aero

No !. 

3.25E+8 was not the conductivity. 

3.25E+8 is the number in SI units that corresponds to the expression used in Meep: it is not the conductivity, it is instead the imaginary part of the relative complex permittivity

Therefore 3.25E+8 corresponds instead to epsilon"/epsilon_o =  0.00288/epsilon_o

(The number really is 3.252698....E+8)

The numerical value of the imaginary part of the permittivity: epsilon"=0.00288 was given by DeltaMass

The conductivity in SI Units that corresponds to epsilon"=0.00288 is:

conductivity        = omega * epsilon"
                          = 2 Pi frequency 0.00288
                          = 2 Pi 2.4E+9 * 0.00288
                          = 4.342937 E+7

which is almost 10 times smaller than 3.25E+8

Please also recall that DeltaMass was conscious that it is incorrect to take 0.00288 as a constant !

That value is a function of frequency.

What is approximately constant in this regime is the conductivity itself.

DeltaMass gave you explicit instructions to keep the conductivity constant, at other frequencies:
for example, the conductivity at 1 GHz is also  4.342937 E+7, so

at 1 GHz you should input into Meep  (3.25...E+8 ) *2.4 = 7.8 E+8, for example

So, for pure Silver, for example (from the table in the link in your post),

Conductivity =  6.090E+07


So, instead of 3.25...E+8 for copper, you have to use   ( 6.090E+07/4.342937 E+7 ) *3.25...E+8 at 2.4GHz

in other words, at 2.4 GHz, your input to Meep for pure Silver should be 1.402276 times higher than for the copper value given by DeltaMass.  About 40% higher, whether in SI units or in Meep units.

In other words, everything else being the same, the quality of resonance (Q) should be about 40% higher with pure silver than with copper.

Here is a complete collection of the above-mentioned equations:

σ=conductivity
ω = angular frequency
f = frequency
ε = complex permittivity
ε = real part of permittivity
ε = imaginary part of permittivity
εo = real part of permittivity of free space
    =8.854187817 E-12
εr = ε/εo (real part of relative permittivity)

ε=ε - i ε  ( Assuming a travelling wave with positive time dependence (exp^(+ i ω t), the negative sign for the imaginary part is required because it implies power loss; while a positive sign would imply power creation, which would violate the laws of thermodynamics)

σ=ω ε
  =2 π f ε

________________________________

DeltaMass model for almost pure copper at microwave frequencies (everything in SI units) :

ε = 0.00288 * (2.4 E+09)/f


therefore

1) σ = conductivity
       = 2 π f ε
       = 2 π f 0.00288*(2.4 E+09)/f
       = 2 π 0.00288*(2.4 E+09)
      = 4.342937 E+07  (constant for any frequency)

2) ε/εo = complex part of relative permittivity
             = (0.00288/εo)*(2.4 E+09)/f
             = (0.00288/(8.854187817 E-12))*(2.4 E+09)/f
             = (3.252698 E+08)*(2.4 E+09)/f   (inversely proportional to frequency)

only for f=2.4 E+09 Hertz one has

ε/εo = 3.252698 E+08

while for f = 2.45 E+09 Hertz (for example) one has

ε/εo = 3.186316 E+08

and for f = 2.35 E+09 Hertz one has

ε/εo = 3.321904 E+08

Observe therefore that it does not make numerical sense to worry about the numerical value of the electromagnetic field calculated by Meep outside the EM Drive having values 24 orders of magnitude lower than the field inside the EM Drive, instead of being perfectly zero, while the model used for modeling copper conductivity should have the relative imaginary permittivity parameter ε/εo vary with frequency instead of being constant.  The difference for this constitutive parameter between 2.4 GHz and 2.45 GHz is of the order of 2%.  Therefore a Meep run with the present model (having  ε/εo a constant with frequency instead of inversely proportional to frequency) with ε/εo = 3.252698 E+08 at 2.45GHz already implies an error of 2%, which is several orders of magnitude larger than the difference between 10^(-24) and zero.

Again, the conductivity is constant with frequency in this frequency range, but the constitutive parameter input into Meep (ε/εo) -which is not the conductivity- should NOT be a constant, it should vary inversely with frequency.
« Last Edit: 12/10/2015 01:03 am by Rodal »

Offline Rodal

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Just a reminder to everyone the math typeit web page is really handy for entering equations that use Greek symbols.

http://math.typeit.org/

Instead of:
CONDUCTIVITY = omega * epsilon"   
                      = omega * tanDelta * epsilon'
                      = omega * tanDelta * epsilon0*epsilon_r
                      = omega * 3.25*(10^8)

σ = Ω ε

Ω = 2πf = 2 * π * 2.4 GHz

My last equation in my message (now deleted) was missing a factor of epsilon0, should have read

                      = omega * 3.25*(10^8)*epsilon0

Offline SteveD

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Except that "symmetrical" is not a precise, correct, statement, because any cavity (including cavities with uniform cross-section for example circular or rectangular cross-section) containing an unsymmetrically placed dielectric are effectively unsymmetric for the purposes of electromagnetic wave propagation (as there is a power loss in the dielectric but effectively insignificant power loss in the empty section, and as the group and phase velocities are different in the dielectric section than in the empty section of the cavity).

. . .

The negative result of Zellerium at a US University with such a cavity is important to be documented (it is still not listed in the EM Drive wiki).

Quote
Update:

I spent the weekend polishing the cylinder and it looks much better (couldn't get some of the bigger scratches out unfortunately). However it definitely improved the VNA plots. Today we tested the attached resonance, seems to be matched very well at 2.434 GHz. But we still don't have a spectrum analysis of our magnetron, so we aren't sure how the power is distributed and how that changes over time. 

The EMF strips arrived to hopefully improve electrical connection between the waveguide and cylinder without the messy Ox Gard. We heard some arcing when the magnetron fired up which seemed to stop (or at least quiet down) as the test continued. We definitely have some deflection but it could easily be due to asymmetric current flow to ground. The x deflection is actually a torque on the cylinder (clockwise if looking from above). This may also be from misalignment of the cylinder axis. The y deflection is in the right direction (towards the dielectric)  and we calculated the force causing it is about 1 mN. Unfortunately our noise level was fairly high so we will need to repeat this test early in the morning when we can get less noise. I'll post the raw data if anyone is interested.

The biggest problem is obtaining symmetric current flow: we've shown that we can get significant deflections on resonance with asymmetric grounding which disappear off resonance. When fields don't build up surface currents are too small to cause a disturbance. We may need to weld our movable plate near a resonant position and manufacture some tuning fixture. However at high power we fear a tuning screw would not work (would probably arc). Are there any other relatively easy analog tuning methods for high power out there?

The simulations are coming along, I've modeled a coax to waveguide to frustum with a VSWR of 1.15 and quality of ~22,000. Changing the length of the coax shifts the resonant frequency (non-linearly which surprised me) but maintains the quality. One question I have yet to answer: how can I model a coax to waveguide bought from a manufacturer without their proprietary information? (i.e. penetration depth and back wall distance) I was able to determine dimensions that give me a VSWR of 1.2 (their maximum quoted value) and used the dimensions for an RG142 coax.



Instead I could model the system with a plane wave excitation, but how do I know the phase of the wave exiting the purchased waveguide? Maybe we should attempt to manufacture this waveguide on our own?
I've emailed the manufacturer back with these questions, perhaps I am missing something or over analyzing...

We've come to the conclusion that a microwave oven magnetron is far from ideal for this application. (As many of you have said before) The wide bandwidth and unpredictable shifting max power make designing any high quality resonator near impossible. Using a circulator could deliver power at the right frequency but would still filter out the majority of the power. And then we don't know how much power is actually being delivered to the cavity... NWPU must have overcome this challenge with a higher tolerance magnetron with a more stable frequency distribution.   

Anyone have any suggestions, comments, questions?

-Kurt

I'd hold off on calling this null for a bit.  Doesn't seem that the expirement progressed to the point that a conclusion could be reached.

Offline OnlyMe

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I looked at the wiki page a few times and I don't believe the data accurately shows the outcome of diy experiments.   Part of the problem is people like to "data reduce" and cherry pick data.    A more scientific method is to establish a protocol to follow for each experiment and to record everything in exacting detail as it is done in a lab notebook.    Each experimental run then has a complete paper record that can be referred to later on.  Video recording is fine but I don't think it is suitable for recording an experiment.   There are too many measurements, changes to the apparatus, etc.  that are not available in a video.    It appears the EW tests did follow this method but I don't believe they provided data on all their tests.   Another aspect of testing is repeatability.   If someone does a test they should try to set up the experiment again under the same conditions and run it again.  These would be recorded as repeats of one experiment where the protocol has not changed.   It may be necessary to allow time for everything to cool down to room temperature and to fiddle with the apparatus so it is setup the same each time.    After several runs have been done - maybe 10 - 20 then run some statistical data analysis.   What is the standard deviation of the "thrust" that was measured?   What is the mean?   Plot the results on a bar graph so the whole set of experiments can be seen.   Now change some part of the experiment and repeat.

Zen-in,

I agree with most of what you say above. In a perfect world it would be good to have every last detail logged and recorded. I expect that within reason the DIYs are keeping such logs. I don't know anything about what is involved in editing Wiki pages and I am not sure that posting every last detail for every experimental run or rerun, on the Wiki page, would be a good idea. For a large part of the Wiki audience it would be just noise. It would be good to have that information available for those with credible experience and the desire to review it.

Where I disagree is on the value of the video record. These are DIY adventures that rely in part (large or small) on the donation of $$, by mostly interested lay persons. Both the Wiki page and especially the videos go a long way toward encouraging that kind of support.

I cannot say how well any of the DIYs have been at keeping an unpublished log of their efforts. Still I have been impressed by their efforts and achievements.

Offline Rodal

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Except that "symmetrical" is not a precise, correct, statement, because any cavity (including cavities with uniform cross-section for example circular or rectangular cross-section) containing an unsymmetrically placed dielectric are effectively unsymmetric for the purposes of electromagnetic wave propagation (as there is a power loss in the dielectric but effectively insignificant power loss in the empty section, and as the group and phase velocities are different in the dielectric section than in the empty section of the cavity).

. . .

The negative result of Zellerium at a US University with such a cavity is important to be documented (it is still not listed in the EM Drive wiki).

Quote
Update:

I spent the weekend polishing the cylinder and it looks much better (couldn't get some of the bigger scratches out unfortunately). However it definitely improved the VNA plots. Today we tested the attached resonance, seems to be matched very well at 2.434 GHz. But we still don't have a spectrum analysis of our magnetron, so we aren't sure how the power is distributed and how that changes over time. 

The EMF strips arrived to hopefully improve electrical connection between the waveguide and cylinder without the messy Ox Gard. We heard some arcing when the magnetron fired up which seemed to stop (or at least quiet down) as the test continued. We definitely have some deflection but it could easily be due to asymmetric current flow to ground. The x deflection is actually a torque on the cylinder (clockwise if looking from above). This may also be from misalignment of the cylinder axis. The y deflection is in the right direction (towards the dielectric)  and we calculated the force causing it is about 1 mN. Unfortunately our noise level was fairly high so we will need to repeat this test early in the morning when we can get less noise. I'll post the raw data if anyone is interested.

The biggest problem is obtaining symmetric current flow: we've shown that we can get significant deflections on resonance with asymmetric grounding which disappear off resonance. When fields don't build up surface currents are too small to cause a disturbance. We may need to weld our movable plate near a resonant position and manufacture some tuning fixture. However at high power we fear a tuning screw would not work (would probably arc). Are there any other relatively easy analog tuning methods for high power out there?

The simulations are coming along, I've modeled a coax to waveguide to frustum with a VSWR of 1.15 and quality of ~22,000. Changing the length of the coax shifts the resonant frequency (non-linearly which surprised me) but maintains the quality. One question I have yet to answer: how can I model a coax to waveguide bought from a manufacturer without their proprietary information? (i.e. penetration depth and back wall distance) I was able to determine dimensions that give me a VSWR of 1.2 (their maximum quoted value) and used the dimensions for an RG142 coax.



Instead I could model the system with a plane wave excitation, but how do I know the phase of the wave exiting the purchased waveguide? Maybe we should attempt to manufacture this waveguide on our own?
I've emailed the manufacturer back with these questions, perhaps I am missing something or over analyzing...

We've come to the conclusion that a microwave oven magnetron is far from ideal for this application. (As many of you have said before) The wide bandwidth and unpredictable shifting max power make designing any high quality resonator near impossible. Using a circulator could deliver power at the right frequency but would still filter out the majority of the power. And then we don't know how much power is actually being delivered to the cavity... NWPU must have overcome this challenge with a higher tolerance magnetron with a more stable frequency distribution.   

Anyone have any suggestions, comments, questions?

-Kurt

I'd hold off on calling this null for a bit.  Doesn't seem that the expirement progressed to the point that a conclusion could be reached.

If one would do that for every experimental result that is negative and doesn't agree with one's expectations, then  negative results are not going to ever be reported, if positive results are not forthcoming.

You would have to define a priori (not a posteriori) what is your time framework for reporting results.

In this case it is clear that Zellerium completed his experiments at the University (glennfish: please note that we are talking about Zellerium's experiments in a University, not DIY in a garage, and Zellerium wrote University reports), and he embarked to other curricular things (you said he actually was going to hand over the work to somebody else to continue it - although it seems that the future work would be on a different geometry, so it is clear that the work on a constant cross-section with unsymmetric dielectric was completed to that extent of the project), so it is quite proper to report such null results.  This is what is generally done in academia and R&D institutions.

Even long-term experimental projects in Universities, as for example Ph.D. theses, that are funded by institutions (for example NASA, DoD, etc.) expect progress reports with reporting of partial results, including negative results.  That was my experience with NASA, the US Navy Research, US Army Research and US Air Force Research, both at Universities and in R&D at different companies.
« Last Edit: 12/05/2015 07:41 pm by Rodal »

Offline Rodal

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I looked at the wiki page a few times and I don't believe the data accurately shows the outcome of diy experiments.   Part of the problem is people like to "data reduce" and cherry pick data.    A more scientific method is to establish a protocol to follow for each experiment and to record everything in exacting detail as it is done in a lab notebook.    Each experimental run then has a complete paper record that can be referred to later on.  Video recording is fine but I don't think it is suitable for recording an experiment.   There are too many measurements, changes to the apparatus, etc.  that are not available in a video.    It appears the EW tests did follow this method but I don't believe they provided data on all their tests.   Another aspect of testing is repeatability.   If someone does a test they should try to set up the experiment again under the same conditions and run it again.  These would be recorded as repeats of one experiment where the protocol has not changed.   It may be necessary to allow time for everything to cool down to room temperature and to fiddle with the apparatus so it is setup the same each time.    After several runs have been done - maybe 10 - 20 then run some statistical data analysis.   What is the standard deviation of the "thrust" that was measured?   What is the mean?   Plot the results on a bar graph so the whole set of experiments can be seen.   Now change some part of the experiment and repeat.

Zen-in,

I agree with most of what you say above. In a perfect world it would be good to have every last detail logged and recorded. I expect that within reason the DIYs are keeping such logs. I don't know anything about what is involved in editing Wiki pages and I am not sure that posting every last detail for every experimental run or rerun, on the Wiki page, would be a good idea. For a large part of the Wiki audience it would be just noise. It would be good to have that information available for those with credible experience and the desire to review it.

Where I disagree is on the value of the video record. These are DIY adventures that rely in part (large or small) on the donation of $$, by mostly interested lay persons. Both the Wiki page and especially the videos go a long way toward encouraging that kind of support.

I cannot say how well any of the DIYs have been at keeping an unpublished log of their efforts. Still I have been impressed by their efforts and achievements.

Please note that some of the experimental work being discussed has been conducted at Universities and they are not DIY work in a home or garage.  There is the work that Zellerium completed on the uniform cross section unsymmetrically placed dielectric cavity -which should be reported, as discussed above, as Zellerium wrote a formal report on it and completed his work to that extent-, and the yet still-to-be-heard of results of research work at a Canadian University using MegaWatts of power, as part of a student's project for example.
« Last Edit: 12/05/2015 07:51 pm by Rodal »

Offline OnlyMe

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I looked at the wiki page a few times and I don't believe the data accurately shows the outcome of diy experiments.   Part of the problem is people like to "data reduce" and cherry pick data.    A more scientific method is to establish a protocol to follow for each experiment and to record everything in exacting detail as it is done in a lab notebook.    Each experimental run then has a complete paper record that can be referred to later on.  Video recording is fine but I don't think it is suitable for recording an experiment.   There are too many measurements, changes to the apparatus, etc.  that are not available in a video.    It appears the EW tests did follow this method but I don't believe they provided data on all their tests.   Another aspect of testing is repeatability.   If someone does a test they should try to set up the experiment again under the same conditions and run it again.  These would be recorded as repeats of one experiment where the protocol has not changed.   It may be necessary to allow time for everything to cool down to room temperature and to fiddle with the apparatus so it is setup the same each time.    After several runs have been done - maybe 10 - 20 then run some statistical data analysis.   What is the standard deviation of the "thrust" that was measured?   What is the mean?   Plot the results on a bar graph so the whole set of experiments can be seen.   Now change some part of the experiment and repeat.

Zen-in,

I agree with most of what you say above. In a perfect world it would be good to have every last detail logged and recorded. I expect that within reason the DIYs are keeping such logs. I don't know anything about what is involved in editing Wiki pages and I am not sure that posting every last detail for every experimental run or rerun, on the Wiki page, would be a good idea. For a large part of the Wiki audience it would be just noise. It would be good to have that information available for those with credible experience and the desire to review it.

Where I disagree is on the value of the video record. These are DIY adventures that rely in part (large or small) on the donation of $$, by mostly interested lay persons. Both the Wiki page and especially the videos go a long way toward encouraging that kind of support.

I cannot say how well any of the DIYs have been at keeping an unpublished log of their efforts. Still I have been impressed by their efforts and achievements.

Please note that some of the experimental work being discussed has been conducted at Universities and it is not DIY in a home or garage work.  There is the work that Zellerium completed on the uniform cross section unsymmetrically placed dielectric cavity, and the yet still-to-be-heard of results of research work at a Canadian University using MegaWatts of power, as part of a student's project for example.

Yes, and Paul March of NASA Eagleworks has posted some updates in the past. But none of those individuals/groups seem to be posting regularly here and wouldn't they be responsible for any of their own detailed information to be posted on Wiki?

As I said I agree in principle. It just seems that it could be a burden in the case of most of those actively posting here.

And my main point was that the photos and videos do play an important fund raising role for the DIYs who have been posting them.

Offline Rodal

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I looked at the wiki page a few times and I don't believe the data accurately shows the outcome of diy experiments.   Part of the problem is people like to "data reduce" and cherry pick data.    A more scientific method is to establish a protocol to follow for each experiment and to record everything in exacting detail as it is done in a lab notebook.    Each experimental run then has a complete paper record that can be referred to later on.  Video recording is fine but I don't think it is suitable for recording an experiment.   There are too many measurements, changes to the apparatus, etc.  that are not available in a video.    It appears the EW tests did follow this method but I don't believe they provided data on all their tests.   Another aspect of testing is repeatability.   If someone does a test they should try to set up the experiment again under the same conditions and run it again.  These would be recorded as repeats of one experiment where the protocol has not changed.   It may be necessary to allow time for everything to cool down to room temperature and to fiddle with the apparatus so it is setup the same each time.    After several runs have been done - maybe 10 - 20 then run some statistical data analysis.   What is the standard deviation of the "thrust" that was measured?   What is the mean?   Plot the results on a bar graph so the whole set of experiments can be seen.   Now change some part of the experiment and repeat.

Zen-in,

I agree with most of what you say above. In a perfect world it would be good to have every last detail logged and recorded. I expect that within reason the DIYs are keeping such logs. I don't know anything about what is involved in editing Wiki pages and I am not sure that posting every last detail for every experimental run or rerun, on the Wiki page, would be a good idea. For a large part of the Wiki audience it would be just noise. It would be good to have that information available for those with credible experience and the desire to review it.

Where I disagree is on the value of the video record. These are DIY adventures that rely in part (large or small) on the donation of $$, by mostly interested lay persons. Both the Wiki page and especially the videos go a long way toward encouraging that kind of support.

I cannot say how well any of the DIYs have been at keeping an unpublished log of their efforts. Still I have been impressed by their efforts and achievements.

Please note that some of the experimental work being discussed has been conducted at Universities and it is not DIY in a home or garage work.  There is the work that Zellerium completed on the uniform cross section unsymmetrically placed dielectric cavity, and the yet still-to-be-heard of results of research work at a Canadian University using MegaWatts of power, as part of a student's project for example.

Yes, and Paul March of NASA Eagleworks has posted some updates in the past. But none of those individuals/groups seem to be posting regularly here and wouldn't they be responsible for any of their own detailed information to be posted on Wiki?

As I said I agree in principle. It just seems that it could be a burden in the case of most of those actively posting here.

And my main point was that the photos and videos do play an important fund raising role for the DIYs who have been posting them.

<<But none of those individuals/groups seem to be posting regularly here and wouldn't they be responsible for any of their own detailed information to be posted on Wiki?>>

No, that would be completely inconsistent:

* the information on Shawyer's on the Wiki was not posted by Shawyer
* the information on Yang's on the Wiki was not posted by Yang
* the information on NASA's on the Wiki was not posted by NASA
* the information on Cannae on the Wiki was not posted by Fetta
* the information on Dresden's on the Wiki was not posted by Dresden
* and so on

*the information on the DIY at Aachen on the Wiki was not posted by the Aachen fellows
*the information on the DIY by Berca on the Wiki was not posted by Berca

therefore the information on Zellerium's experimental work at the University (he published a formal report on the results) should also be posted, just like the work at Dresden, etc.
« Last Edit: 12/05/2015 08:08 pm by Rodal »

Offline aero

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I have a question.

What results from E cross B when there is no mass? That is, in a vacuum. And how strong does the electric field need to be to ionize air in the atmosphere? Would we see an E x B drift in that case?
Retired, working interesting problems

Offline Rodal

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...
I've always been reluctant to update the wiki page on anyone other than my own experiment. Whats your thoughts Doc. I didn't start the wiki...
Well, I didn't start the Wiki either.

I only contributed to the Experimental Spreadsheet, actually I was the one that filled (and curated) most of the data for the Wiki spreadsheet -except for your experiment-.

Until I did not have any more time available to continue posting here, or updating the Wiki.

I'm definitely getting the impression that there is a lack of volunteers to fill the Wiki spreadsheet with the data from Zellerium's report.

In other words: the consensus at the present time appears to be that it is nor worth anybody's time to curate the Wiki's spreadsheet on experimental results.
« Last Edit: 12/05/2015 09:20 pm by Rodal »

Offline zen-in

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I looked at the wiki page a few times and I don't believe the data accurately shows the outcome of diy experiments.   Part of the problem is people like to "data reduce" and cherry pick data.    A more scientific method is to establish a protocol to follow for each experiment and to record everything in exacting detail as it is done in a lab notebook.    Each experimental run then has a complete paper record that can be referred to later on.  Video recording is fine but I don't think it is suitable for recording an experiment.   There are too many measurements, changes to the apparatus, etc.  that are not available in a video.    It appears the EW tests did follow this method but I don't believe they provided data on all their tests.   Another aspect of testing is repeatability.   If someone does a test they should try to set up the experiment again under the same conditions and run it again.  These would be recorded as repeats of one experiment where the protocol has not changed.   It may be necessary to allow time for everything to cool down to room temperature and to fiddle with the apparatus so it is setup the same each time.    After several runs have been done - maybe 10 - 20 then run some statistical data analysis.   What is the standard deviation of the "thrust" that was measured?   What is the mean?   Plot the results on a bar graph so the whole set of experiments can be seen.   Now change some part of the experiment and repeat.

Zen-in,

I agree with most of what you say above. In a perfect world it would be good to have every last detail logged and recorded. I expect that within reason the DIYs are keeping such logs. I don't know anything about what is involved in editing Wiki pages and I am not sure that posting every last detail for every experimental run or rerun, on the Wiki page, would be a good idea. For a large part of the Wiki audience it would be just noise. It would be good to have that information available for those with credible experience and the desire to review it.

Where I disagree is on the value of the video record. These are DIY adventures that rely in part (large or small) on the donation of $$, by mostly interested lay persons. Both the Wiki page and especially the videos go a long way toward encouraging that kind of support.

I cannot say how well any of the DIYs have been at keeping an unpublished log of their efforts. Still I have been impressed by their efforts and achievements.

If experimenters want to make videos of their experiments that is their choice.  I'm not saying they shouldn't do that.  I'm not trying to be the Taliban here.   But the recording of experimental results should not rely on just a video.   I don't think it's a lot to expect experimenters to record as much from their experiments as possible.   A lab notebook, with carefully written notes (in ink!!) of each experiment is a reward in itself.   It's a nice momento for the experimenter and allows easy, unambiguous references to the results of the experiment.   If data is recorded into a file, and written to a CD-ROM the reference to that file can be included.   One of the most important things here is to perform multiple runs of an experiment and then do the analysis of the data.    Showing these results doesn't take up a lot of space if it is shown as a graph.
« Last Edit: 12/05/2015 08:46 pm by zen-in »

Offline SteveD

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On repeatability, I've been thinking that the current balance beam setups might be a problem.  Each one introduces a bunch of unknowns, and no tow beams are going to work alike. 

Simply sitting a frustum on a modern digital scale might cause RFI.

So I got to thinking about the old tri-beam balances I used in high school.  Why not measure on a completely analog scale?  Dial in the weight of the frustum, let it stablize and if the thing moved that's interesting.

While led me to find these things:



And I got to thinking, put a frustum on one end and dial in the weight and you could:

1.  Place a level showing distance in mm on the other end, shoot a laser pointer at it, and measure the amount of displacement on the level with a digital camera.

2.  Put a laser displacement sensor under the unused side to measure very small movements.

The upshot of this is that you can model the effect of lift and downward thrust by placing weights on either side of the balance.

People here don't like the idea because of concerns about the magnetic dampening used.  I still think this setup might be a useful tool in allowing tests to be done on a bench, and not requiring a large beam setup.  Better yet it uses a measuring tool that can be easily acquired.

Which brings me to my gold standard EMDrive test:

1.  Get a tripple beam balance rated to around 2600g with 0.1g resolution.  I could be wrong, but I can't see any mention of any form of dampening on these things.

2.  Get a frustum believed to have at least 0.1 grams of thrust in a vacuum.  Preferably an integrated test article.

3.  Point frustum so that the thrust is directed downward with the thing on the tripple balance beam scale in a vacuum chamber (testing in a vacuum).

4.  If the thing moves downward (especially on the integrated setup) then rebuild the setup with a balance made of non-ferrous polymers.  If you're still getting 0.1 grams of force, then I'd be hard pressed to say that it's anything but thrust.  No air, no electronics to get fouled, probably nothing magnetic to cause the effect.

5. Flip and check to make sure the effect still exists inverted.

Offline OnlyMe

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On repeatability, I've been thinking that the current balance beam setups might be a problem.  Each one introduces a bunch of unknowns, and no tow beams are going to work alike. 

Simply sitting a frustum on a modern digital scale might cause RFI.

So I got to thinking about the old tri-beam balances I used in high school.  Why not measure on a completely analog scale?  Dial in the weight of the frustum, let it stablize and if the thing moved that's interesting.

While led me to find these things:



And I got to thinking, put a frustum on one end and dial in the weight and you could:

1.  Place a level showing distance in mm on the other end, shoot a laser pointer at it, and measure the amount of displacement on the level with a digital camera.

2.  Put a laser displacement sensor under the unused side to measure very small movements.

The upshot of this is that you can model the effect of lift and downward thrust by placing weights on either side of the balance.

People here don't like the idea because of concerns about the magnetic dampening used.  I still think this setup might be a useful tool in allowing tests to be done on a bench, and not requiring a large beam setup.  Better yet it uses a measuring tool that can be easily acquired.

Which brings me to my gold standard EMDrive test:

1.  Get a tripple beam balance rated to around 2600g with 0.1g resolution.  I could be wrong, but I can't see any mention of any form of dampening on these things.

2.  Get a frustum believed to have at least 0.1 grams of thrust in a vacuum.  Preferably an integrated test article.

3.  Point frustum so that the thrust is directed downward with the thing on the tripple balance beam scale in a vacuum chamber (testing in a vacuum).

4.  If the thing moves downward (especially on the integrated setup) then rebuild the setup with a balance made of non-ferrous polymers.  If you're still getting 0.1 grams of force, then I'd be hard pressed to say that it's anything but thrust.  No air, no electronics to get fouled, probably nothing magnetic to cause the effect.

5. Flip and check to make sure the effect still exists inverted.

I think the balance beams that both rfmwguy used and SeeShells has set up are just more accurate versions of your off the shelf triple beam. I think the digital scale Shell incorporates in her set up measures to 0.01g.

Switching to a carbon fiber beam or some other material that is both ridged enough and less prone to expansion from heat, is a good idea but the cost is a bit high for an early stage balance.

Could be wrong but that's the impression I get.
« Last Edit: 12/05/2015 09:21 pm by OnlyMe »

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