Author Topic: EM Drive Developments - related to space flight applications - Thread 9  (Read 1671956 times)

Offline PotomacNeuron

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Thank you! I think if you keep moving the settings to other directions, you will find zero and negative positions. If so, draw a force_vs_direction plot, it may be evident that Lorentz force is at work.
The fact that the test setup is oriented in the East - West direction means that the Earth magnetic field is roughly perpendicular to the flow of the DC portion of the electric circuit. The associated perturbative Lorentz force should be so close to its maximum.
The fact that according to its orientation the action is mainly additive or substractive to the supposed EM-drive effect could be assessed by a test performed after a flip of the direct and return parts of the DC circuit or a flip of the frustum orientation.

The force might be in its maximum, but it is the torque that is the main factor that influences the balance displacement. If the DC loop is in the vertical plane defined by gravity and the balance arm, when the arm is in East - West direction, we will see the thrust to be close to its minimum (zero, if the loop is perfectly in the said plane). This claim is supported both by experiment and by theory.

The attached picture is a screenshot from may paper, https://arxiv.org/pdf/1510.07752.pdf, fig 5. In my experiment, when the arm pointed to the East, the thrust was much smaller than when it pointed to the North.

Theoretically, the measured 'thrust' is related to the torque. When the said plane where the DC loop resides is parallel to the magnetic field (this is the case when arm points North - South), the Lorentz forces caused by currents in the two vertical lines of the loop point to opposite directions, and both are perpendicular to the plane, maximizing the torque. On the other hand, if the arm points East - West, the two opposite forces are in the same plane, minimizing the torque.

Potomac,

Some peer review for your paper:


Thank you very much. Your review is much appreciated. I answer the questions below.

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1. With a P-val of 0.008 it is clear that there is a statistically significant difference between the states, however there is no mention of the methodology behind the error bars. Was the standard error of the mean used or is each tail simply 1 standard deviation? How about other sources of error, is the cylinder/pseudo-amplifier hollow, where do they orientate, do they resonate?



I suppose you are talking about the test shown in Fig 6 of the paper. It was similar to the test shown in Fig 4 where the p-value was 1.4*10^(-8), or with 5 sigma significance. The test in Fig. 6 was done with less repeats thus had lower significance level. The methods, original data, computer programs, and photos were in supplemental material which was not upload because of its size. But it is available with request. The test was stated in the paper as paired t-test, which meant the subtraction of displacements under the C-connected condition and the C-disconnected condition were compared with 0. This specific test probably was run with 3 repeats thus 3 data points was compared to 0 using t-test. I suppose the degree of freedom is 3-1=2. [update: No, not paired t-test but the ordinary t-test to compare the means of two groups. I was influenced by Fig 5 when I was answering the question. Sorry for the bad memory.]

There was no RF involved in this paper, thus the resonance of the cylinder and/or the pseudo-amplifier was not relevant. They were both made from 1/2 copper plumbing tubes. The cylinder had both ends sealed with 1/2 copper plumbing caps. The pseudo-amplifier had one end open and the other end contacted the beam. pseudo-amplifier was effectively a grounding point electrically.

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2. What are the damping parameters of both the magnetic and oil dampers? Did you measure oscillations over time or is each displacement result simply the mean orientation over time? How long after power on did you measure? In other words, what is the resolution and oscillation period of your device?


Damping parameters were not measured. Only the time needed for the read-out to be stable was estimated roughly. The damping was close to critical damping (judged from video; link below). The displacement had a small overshot then came back a little bit. For the magnetic damp, it was estimated that after 15 seconds, the displacement measured would be stable without identifiable change. For the oil damping, I forgot the story (maybe described in the supplemental material; roughly remembered to be longer than 15 seconds). But the read-out of the displacement were recorded after the oscillations died-out. The calliberation step was recorded in this video clip,
In the video the laser spot was a big lump caused by brightness saturation. In real life the spot had fine features that could be used to more accurately read out the displacements.

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3. Was lorentz force and torque on the steel wire accounted for? Was there shielding between the copper cylinder and the beam/other components? How about the external shielding against thermal and atmospheric turbulence? How did the change of return path shape change the displacement force?


There was no DC current in the steel wire thus no Lorentz force from it. The torque of the steel wire was the torque that countered the Lorentz torque to stop the displacement from increasing unboundedly during a test. The copper cylinder and the beam had a connection point "C" as shown in Fig 1 and Fig 2. The copper cylinder was also electrically connected to the pseudo-amplifier through the outer layer of the coaxial cable that connected them.

The tests was done under a table (with a small hole to run the steel wire through) where all 4 side openings under the table were boarded roughly to fend off air turbulence. Acrylic sheets were used in places where the laser or lighting needed to go through. Shape of the return path can be altered by shaping the RF cable that connected point "C" and the pseudo-amplifier. No measurement was made. Only observations were made that that the displacements were different with different shapes.

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4. Have you considered condensation and thermal plumes arising from the ice bath? Is the apparatus level and evenly balanced in all 3 dimensions?


The ice box was padded with thermal foam on the outer side to avoid condensation. To deal with thermal plume problem, the ice box was designed to be under the middle of the beam at a point where the steel wire was connected. But no measurement was done.

The level was leveled horizontally. For the other two dimensions, leveling was not tried for the following reasons: 1. The laser mirror was mounted on the lower end of the steel wire; Because the steel wire was vertical, any movement of the arm on the other dimensions will not affect the reflected laser. 2. Because of the weight of the icebox, and most of the components are symmetrical, the arm was supposed to be near level in the other two dimensions.

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5. Is an effect size of 41uN/20.72W aka 1.98uN/W, statistically significant when considering effect sizes several orders of magnitude higher?


I suppose you get 20.72W from 3.7V times 5.9 Amperes. That was the DC power consumed. It was all dissipated as heat as there was no RF involved in the experiment. That 1.98uN/W was very significant, the p-value was 1.4*10(-8), (a 5 sigma experiment). But this thrust was not the "EmDrive thrust". It merely was a "Lorentz force thurst" that might be mistaken as EmDrive thrust if an experimenter was not careful, as what I think happened in the EW 2014 paper.

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6. What is the RF cable and what does it do with the copper cylinder?


The RF cable was a coaxial cable. The outer layer was electrically connected to the copper cylinder wall and the pseudo-amplifier wall. The inner layer was not connected to the copper cylinder. It extruded into the cylinder through a hole to mimic an antenna inside of the cylinder, and was electrically grounded inside the pseudo-amplifier. The function of the cable in this experiment was to provide a DC return path, intentionally in this experiment and unintentionally in the EW 2014 experiment.

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7. Edit: I could also talk about the very small sample size, though that is more of a question for follow-up experiments and replications.


This is a question I'd love to elaborate. For the Fig 4 test, the sample size was not small because the test yielded a p-value of 1.4*10^(-8). For Fig 6 and Fig 5, we ran small of sample sizes because the mom of the household started to threaten us for being stayed in the basement for long. The original plan was to experiment with 8 directions but we ended with 3 (North, North-East and East).

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The idea behind the experiment is valid but this experiment, in my humble opinion, is not statistically valid and the results do prove an effect though the conclusion that this may have a considerable impact on "EM Drive" thrusts is not supported by the methodology and results. I hope that this proves helpful :)     

This paper was not well written because we tried to reach 2 goals at the same time. One was for its educational value so that we could publish it in The Physics Teacher (though denied, maybe for the same reason I talked here) and the other was to propose an effect that was not controlled in the EW's 2014 paper. There was word count limit that did not help. I think for the later purpose, although the paper was not well written, the design was valid and the experiments served well that purpose.

 Whoever interested in the supplemental material can email me (email shown in the paper) to obtain a copy. Thanks!

LowerAtmosphere, Thank you for spending your time to review the paper. As any other amateur researcher will agree, the nightmare for me is not that others do not agree with me, but is that nobody pays attention to my work.
« Last Edit: 04/21/2017 10:54 pm by PotomacNeuron »
I am working on the ultimate mission human beings are made for.

Offline X_RaY

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Quote from: PotomacNeuron
LowerAtmosphere, Thank you for spending your time to review the paper. As any other amateur researcher will agree, the nightmare for me is not that others do not agree with me, but is that nobody pays attention to my work.

You can be sure your work pay attention to the public, at least to the active members here since it's shown in this forum. ;) And of course your results are quite interesting. I am sure the experimenters will consider how to take your results into account. So please keep on. It helps to find the trueness regarding the experiments. The caraterisation of the pendulum with all possible error sources is very importaint before starting W powered tests. :) Even when everything boils down and can be explained by well known physics, each piece of the puzzle is important to find the truth.
« Last Edit: 04/21/2017 08:12 pm by X_RaY »

Offline LowerAtmosphere

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Dear Potomac,

As X_Ray said, just by virtue of posting here your work has entered the public domain and is now a part of the literature which surrounds this phenomenon. Personally, I am very satisfied with your answers and they show that the paper has some merit after all :) Experimenters and theoreticians alike should take note that finding the resolution/signal to noise ratio/minimum significant force for your balance is more important than the results you get from using it. Everybody can build a balance, though when measuring forces of this magnitude it is vital that you prove that the measuring device actually measures the effect sufficiently. The experiment does (or does not) confirm the hypothesis, while your methodology proves the experiment's validity.

~L.A.
« Last Edit: 04/21/2017 09:41 pm by LowerAtmosphere »

Offline ThatOtherGuy

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Folks, could you please have a look at this patent and tell me what do you think

https://www.google.com/patents/US8459002

What the heck?!?

Offline demofsky

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Folks, could you please have a look at this patent and tell me what do you think

https://www.google.com/patents/US8459002

What the heck?!?
What is interesting about this is the complex modulation schemes implied.  This was mentioned earlier by someone speculating about the potential effects of AM vs FM frequencies within a cavity and may be a fruitful area of investigation for EM drives.

In essence, the patent could be interpreted as the complex modulation of a medium (magnet, directric).  The EM drive is typically seen as a resonating cavity but fundamentally there is a modulated medium within the cavity for resonance to occur.  (And boy am I genuinely interested to see how folks qualify this last statement of mine!  :D )
« Last Edit: 04/22/2017 07:37 am by demofsky »

Offline LowerAtmosphere

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Folks, could you please have a look at this patent and tell me what do you think

https://www.google.com/patents/US8459002

What the heck?!?
What is interesting about this is the complex modulation schemes implied.  This was mentioned earlier by someone speculating about the potential effects of AM vs FM frequencies within a cavity and may be a fruitful area of investigation for EM drives.

In essence, the patent could be interpreted as the complex modulation of a medium (magnet, directric).  The EM drive is typically seen as a resonating cavity but fundamentally there is a modulated medium within the cavity for resonance to occur.  (And boy am I genuinely interested to see how folks qualify this last statement of mine!  :D )
Isn't frequency modulation as shown in Fig 2 similar if not identical to resonance ocurring at one end of a closed cavity system? I have a strange suspicion that the device is an EM Drive in disguise.
« Last Edit: 04/22/2017 08:49 am by LowerAtmosphere »

Offline Mark7777777

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I scanned it to see if they quantified how much thrust they thought they could get per watt but I couldn't see such a figure. Anyone spot an estimate?

 ;)
Folks, could you please have a look at this patent and tell me what do you think

https://www.google.com/patents/US8459002

What the heck?!?

Offline ThatOtherGuy

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« Last Edit: 04/22/2017 10:51 am by ThatOtherGuy »

Offline ThatOtherGuy

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I scanned it to see if they quantified how much thrust they thought they could get per watt but I couldn't see such a figure. Anyone spot an estimate?

 ;)
Folks, could you please have a look at this patent and tell me what do you think

https://www.google.com/patents/US8459002

What the heck?!?

Assuming that there IS any trust :)


Edit:

See figure #4 (here)
« Last Edit: 04/22/2017 03:55 pm by ThatOtherGuy »

Offline ThatOtherGuy

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This is a second very simple wiring option that I am seriously considering, but I would need to purchase a $250 100W attenuator to make it work.     :'(  The Windfreak NV signal generator has an onboard power detector that I have tested and it works very well. It also has well documented/commented software: https://windfreaktech.com/wp-content/uploads/docs/synthnv/serialcomm.pdf
Would be a fairly simple matter to write new control software that monitors the reflected power while automatically adjusting signal frequency.

Well, there are cheaper critters, but then I'm not sure they may be suitable

https://www.aliexpress.com/cheap/cheap-100w-rf-attenuator.html

I think most of them will work well enough. Whether or not they can really sustain 100W for an indefinite duration (less than likely) is not that much of an issue considering a 30W signal source and test times in minutes rather than days.

what about these

https://www.rfmw.com/ProductDetail/83A70462000F-EMC-Technology-Inc/472825/pid=1755

sure, they're pretty much DIY, but then, I don't think it may be a huge problem :)


Offline meberbs

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Folks, could you please have a look at this patent and tell me what do you think

https://www.google.com/patents/US8459002

What the heck?!?
They say
Quote
It uses two electromagnets, which are separated by a short distance and are operated with modulated currents such that the forces on the two magnets are not balanced.
This sounds like concepts that people have come here in multiple threads to propose.

In summary, what they create is effectively a phased array antenna. It is true that the forces are not balanced, because it emits RF energy (photons) in asymmetric directions. The force per power will be a bit less than the 1/c of a laser, since you would need a very large array at RF frequencies to get good directionality.

If you doubt that it is a phased array antenna, they even say:
Quote
This propulsion concept uses circuits that operate in the radio frequency (RF) spectrum. As such, it can also be used as an RF communication system.

Offline Monomorphic

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This is a second very simple wiring option that I am seriously considering, but I would need to purchase a $250 100W attenuator to make it work.     :'(  The Windfreak NV signal generator has an onboard power detector that I have tested and it works very well. It also has well documented/commented software: https://windfreaktech.com/wp-content/uploads/docs/synthnv/serialcomm.pdf
Would be a fairly simple matter to write new control software that monitors the reflected power while automatically adjusting signal frequency.

Well, there are cheaper critters, but then I'm not sure they may be suitable

https://www.aliexpress.com/cheap/cheap-100w-rf-attenuator.html

I think most of them will work well enough. Whether or not they can really sustain 100W for an indefinite duration (less than likely) is not that much of an issue considering a 30W signal source and test times in minutes rather than days.

what about these

https://www.rfmw.com/ProductDetail/83A70462000F-EMC-Technology-Inc/472825/pid=1755

sure, they're pretty much DIY, but then, I don't think it may be a huge problem :)

In this type of experiment, the attenuator's maximum wattage needs to be many times that of the RF source. A 20W attenuator will heat up VERY quickly under a 20W load and begin shedding vortices. The attenuator needs to be able to absorb the heat generated over a few minutes without significant heating.
« Last Edit: 04/22/2017 10:03 pm by Monomorphic »

Offline ThatOtherGuy

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Good point, indeed !

As a note the same brand also makes 100w chips in case they may be suitable and in such a case you may build your own heatsink be it wax or ... mineral oil ;)
« Last Edit: 04/22/2017 10:46 pm by ThatOtherGuy »

Offline Mark7777777

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Thanks. So that would be up to 12,000 ounces of thrust for 2,000 watts.

So 6 ounces (170.1 grams) of thrust per watt.


I scanned it to see if they quantified how much thrust they thought they could get per watt but I couldn't see such a figure. Anyone spot an estimate?

 ;)
Folks, could you please have a look at this patent and tell me what do you think

https://www.google.com/patents/US8459002

What the heck?!?

Assuming that there IS any trust :)


Edit:

See figure #4 (here)

Offline LowerAtmosphere

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Thanks. So that would be up to 12,000 ounces of thrust for 2,000 watts.

So 6 ounces (170.1 grams) of thrust per watt.


I scanned it to see if they quantified how much thrust they thought they could get per watt but I couldn't see such a figure. Anyone spot an estimate?

 ;)
Folks, could you please have a look at this patent and tell me what do you think

https://www.google.com/patents/US8459002

What the heck?!?

Assuming that there IS any trust :)


Edit:

See figure #4 (here)

If this is true, you could easily achieve solar propelled flight* and jetpacks etc.     

Unfortunately, those thrust levels are impossible given the input. Connecting this 1.6675N/w system with a fairly average electric generator of 3000w/19N (newton value calculated as engine torque force) is over-unity, is it not?

*http://www.solardesigntool.com/components/module-panel-solar/Sunpower/3246/SPR-X22-360/specification-data-sheet.html 

Offline ThatOtherGuy

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I wonder how those figures were obtained, I mean if they are just some kind of approx estimate or if they came out from tests and measurements and if so it would be interesting to know how those tests were conducted

Offline Mezzenile

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Nice to see your article on this subject ! I agree with the fact that the final effect of Lorentz force generation is through the induced torque around the suspension wire of the test set up. But my point was to see if its effect was to enhance or to reduce the observed displacement associated with the EM-drive effect.

Lorentz forces / torques induced on a DC circuit  by the earth magnetic field are used on geostationnary satellites for attitude control.
In fact if we manage to put the test set-up in an initial position where the resulting magnetic moment of its electrical circuit has the same direction than the local earth magnetic field, then the perturbative torque should be zero at this rest position.
Moreover if during the test, a displacement due to an EM-Drive effect really occurs, then the magnetic torque due to the interaction with the earth magnetic field should be always in opposition to this displacement. So at this particular position of the test set-up, the displacement due to a possible EM-Drive phenomena should be always under estimated.
This gives confidence in the possibility to eliminate this source of perturbation in the demonstration that the EM-Drive effect really exists.

Offline Monomorphic

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14.8V 10,000mAH lipo battery arrived.  This is what will power the 30W main amplifier. This is the biggest lipo i've ever held! This is a very dangerous battery so it must be stored in a metal box and never left unattended while charging/discharging.  :o

Offline ThatOtherGuy

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LOL are you building a bomb, by chance :) ?

Seriously, what about the attenuator ?
« Last Edit: 04/24/2017 05:28 pm by ThatOtherGuy »

Offline Mezzenile

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14.8V 10,000mAH lipo battery arrived.  This is what will power the 30W main amplifier. This is the biggest lipo i've ever held! This is a very dangerous battery so it must be stored in a metal box and never left unattended while charging/discharging.  :o
Beware to excessive temperature variations especially high temperatures which can cause a thermal runaway reaction that ignites a fire and consequently cause an explosion.

Normally Lithium battery aging is reduced if its storage (no charging) is made at low temperature (no freezing).

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