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#360 by Mark7777777 on 01 Sep, 2020 09:09
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Checkout the Clyde Space Epic 12U Plus CubeSat offering.
https://www.aac-clyde.space/epic-spacecraft/epic-12
Then install a 140mm long, 20mN, EmDrive thruster, 40W RF amp & control electronics.
Full DIY details in the paper.
In a recent video:
, Roger Sawyer talks about 2nd, 3rd and 4th generation theoretical Emdrives. (See time position 33:45 for 3rd generation.)
Has Roger actually got any working versions of any of these? Or are they just what he thinks could be made?
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#361 by Bob Woods on 01 Sep, 2020 14:22
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If one clearly worked, it would be in the news world-wide. And this forum would be inundated with posts.Checkout the Clyde Space Epic 12U Plus CubeSat offering.
Roger Sawyer talks about 2nd, 3rd and 4th generation theoretical Emdrives. (See time position 33:45 for 3rd generation.)
https://www.aac-clyde.space/epic-spacecraft/epic-12
Then install a 140mm long, 20mN, EmDrive thruster, 40W RF amp & control electronics.
Full DIY details in the paper.
Has Roger actually got any working versions of any of these? Or are they just what he thinks could be made?
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#362 by JohnFornaro on 01 Sep, 2020 14:44
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Have been told [Shawyer's paper] includes details of the spreadsheet used to calc the various physical dimensions plus other new data & insights.
Humans cannot travel to other planets by using spreadsheets. -
#363 by Star One on 12 Sep, 2020 08:15
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By the looks of it & going by this article we should soon see the back of the so called EM Drive.
This is about the most interesting thing from the article. I feel sorry for him, if that wasn’t what science is all about, having to expend all that time and effort on something he knows going into doesn’t work.QuoteJose Luis Perez Diaz in Madrid, Spain, and Martin Tajmar in Dresden, Germany, are carrying out the experimental side of the project. Tajmar confirms that he plans to publish two papers in February 2021, one on the “normal” microwave EmDrives and the other on the laser-based EmDrives. On the experimental side, Tajmar is still working on eliminating every possible source of error.
“We are still improving our balances and testing continues, “ says Tajmar. “In particular we are working on further reduction of magnetic field interactions with the environment, which was the major side-effect that we discovered in previous testing.”
When asked whether he might have an alternative explanation for the apparent thrust seen in previous tests, Tajmar only says to “Wait for the papers...”
Pretty damming this section of the article.QuoteBrice Cassenti, an expert in advanced propulsion systems at the University of Connecticut, goes with the general view that the EmDrive does not seem plausible because it violates the law of conservation of momentum.
“Only the electromagnetic waves emitted by the conical antenna can provide a momentum change, that can provide a force, and the force is several orders of magnitude too small,” Cassenti told Popular Mechanics. He believes the EmDrive’s enduring popularity with DARPA is because of the promise it offers.
“Many enthusiastic individuals want to believe it is a method that can be used to escape the constraints of known physical principles on space propulsion systems and open up humanity to voyages to the stars,” says Cassenti.
Cassenti believes it is important to explore new and challenging concepts, but given the infinite variety on offer, he prefers those with the backing of known physics. “In my opinion, it will always be better to invest engineering efforts in existing avenues that satisfy known physical principles and gradually build up science in new avenues for engineers to explore,” says Cassenti.
https://www.popularmechanics.com/space/rockets/a33917439/emdrive-wont-die/ -
#364 by flux_capacitor on 19 Sep, 2020 16:25
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Larry Reed, a retired American aerospace engineer, author of the book Quantum Wave Mechanics (Booklocker 2020, ISBN 978-1634929646, also available here in PDF — Edit: sorry, contents + preface of the book only in this link)
has put a document online, entitled "EM propulsion drive": https://www.academia.edu/44118894/EM_propulsion_drive
I've just skimmed through very quickly. I noticed diagrams about Doppler shifts within a moving (accelerating) cavity.
Has anybody ever heard of Mr Reed? What do you guys think of the paper?
EDIT2: Chapters 1 to 7 of the book are available for free at https://www.academia.edu/44096967/extract_Quantum_Wave_Mechanics_Ch_1_7_pdf
Chapter 52 is supposed to deal with "antigravity"… but after extensive research the book is clearly unavailable from all possible online sources.
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#365 by demofsky on 22 Sep, 2020 05:45
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Ok, new article covering latest EM drive projects. Most notably the Spanish are claiming their fibre optic loop experiment is getting 0.1 N/Kw! 😱😱
Usual caveats apply, specifically apparatus and experimental design. However, at 0.1 N/Kw a more clear potential signal may mean that experimentalists are not quite confronted with the need to create the equivalent of an electron microscope using aquarium parts. (However heroically.)
https://www.nextbigfuture.com/2020/09/darpa-laser-version-of-emdrive-has-a-test-result-better-than-commercial-ion-drive.html -
#366 by sghill on 22 Sep, 2020 12:42
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Ok, new article covering latest EM drive projects. Most notably the Spanish are claiming their fibre optic loop experiment is getting 0.1 N/Kw! 😱😱
Usual caveats apply, specifically apparatus and experimental design. However, at 0.1 N/Kw a more clear potential signal may mean that experimentalists are not quite confronted with the need to create the equivalent of an electron microscope using aquarium parts. (However heroically.)
https://www.nextbigfuture.com/2020/09/darpa-laser-version-of-emdrive-has-a-test-result-better-than-commercial-ion-drive.html
My goodness! A 5N thruster could practically float itself on Earth! Granted, you need a 50kW extension cord!
At this conversion rate, we could easily be looking at 1g acceleration for Starship-sized vessels using current power generating technologies. Mars would be only a two day flight with a deacceleration burn half-way through the flight! https://space.stackexchange.com/questions/840/how-fast-will-1g-get-you-there
Still though, if it really works, this result is so much higher than the noise floor that unrefutably clear demonstrations will be possible in high school science labs.
Also, if the Spanish (or anyone) can prove this thruster works, QI's role in Physics is also going to get a bit more discussion (to wildly understate it).
photo credit: from the nextbigfuture.com article
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#367 by Elmar Moelzer on 23 Sep, 2020 04:03
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Yeah, not trying to be a downer, but it looks like that one is a dud too...
https://twitter.com/memcculloch/status/1308314973534384129QuoteImportant to keep you honestly up to date on here. Just received an email from Tajmar that says the force he found was out-gassing from adhesive tape! So we're back to one positive, one negative. So nice to learn of this on the day of our presentation to DARPA. Fate is a comedian
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#368 by Mark7777777 on 23 Sep, 2020 09:37
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Yeah, not trying to be a downer, but it looks like that one is a dud too...
https://twitter.com/memcculloch/status/1308314973534384129QuoteImportant to keep you honestly up to date on here. Just received an email from Tajmar that says the force he found was out-gassing from adhesive tape! So we're back to one positive, one negative. So nice to learn of this on the day of our presentation to DARPA. Fate is a comedian
Not so sure -- Tajmar also reported his 3 previous tests all had thrusts. -
#369 by asmith47 on 23 Sep, 2020 10:23
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Please delete this post at your discretion for whatever reason.
I've been following these threads for years, am in no way an EM engineer or otherwise qualified. Just super interested in the potential in such a drive.
Anyway, this article came across my feed
https://scitechdaily.com/large-hadron-collider-creates-matter-from-light/
And immediately thought photon = reaction mass.
The bad news is the amount of energy required but it is sort of precedence of EM -> Reaction mass?
Right?
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#370 by Bob Woods on 25 Sep, 2020 20:03
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Please delete this post at your discretion for whatever reason.
Like you, I don't have the chops to claim the requisite knowledge, but I have posted here before about bosons, specifically Z bosons being created/manipulated with EM radiation. Z bosons because I understand that they are integer spin, associated with the transfer of momentum. Sounds like a possible suspect by my guess.
I've been following these threads for years, am in no way an EM engineer or otherwise qualified. Just super interested in the potential in such a drive.
Anyway, this article came across my feed
https://scitechdaily.com/large-hadron-collider-creates-matter-from-light/
And immediately thought photon = reaction mass.
The bad news is the amount of energy required but it is sort of precedence of EM -> Reaction mass?
Right?
Making pure speculation, if you had an atomic lattice structure of a particular topology, could as stream of incident photons be reflected in such a way to induce a momentary neutral charge spin of 1, thereby creating a Z boson and transfer/create momentum within the lattice? Z bosons have exceedingly short lifetimes, but are about the size of a proton from what I have read.
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#371 by Alex_O on 26 Sep, 2020 20:11
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Larry Reed, a retired American aerospace engineer, author of the book Quantum Wave Mechanics (Booklocker 2020, ISBN 978-1634929646, also available here in PDF — Edit: sorry, contents + preface of the book only in this link)
has put a document online, entitled "EM propulsion drive": https://www.academia.edu/44118894/EM_propulsion_drive
I've just skimmed through very quickly. I noticed diagrams about Doppler shifts within a moving (accelerating) cavity.
Has anybody ever heard of Mr Reed? What do you guys think of the paper?
EDIT2: Chapters 1 to 7 of the book are available for free at https://www.academia.edu/44096967/extract_Quantum_Wave_Mechanics_Ch_1_7_pdf
Chapter 52 is supposed to deal with "antigravity"… but after extensive research the book is clearly unavailable from all possible online sources.
Hi, thanks for sharing about Larry's work, I found a download link for all chapters (16 files)
https://independent.academia.edu/LarryReed
..
Upd, sorry, I need to think more, sorry -
#372 by flux_capacitor on 03 Oct, 2020 18:10
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Upd, sorry, I need to think more, sorry
No, no Alex, you were right! The full book is indeed available for free in the section "books" on top of the URL you gave, split in 9 PDF files. They were created 15 and 16 September 2020 and I'm quite sure they were not there last time I checked… so either this is a coincidence, or Mr Reed heard of some discussion here and there…
I've asked the editor about the apparent unavailability of the book anywhere. They answered this is because the book is currently undergoing a series of revisions.
Some sections of the book are missing as the PDFs lack some pages. Maybe these missing pages are a consequence of the reorganization of the book into a 4th edition?
Whatever, I have compiled the 9 separate files into one single large PDF and added missing blank pages to recover a consistent page numbering. I've also created a clickable table of contents as bookmarks, that should be visible in your PDF reader, because the book is HUGE (700 pages with a lot of figures and tables).
About this incredible density and quality of such work (speaking of the form, not the substance as I don't have any opinion about the physics yet) I wonder if this is junk physics explained with garbage word salad, or if there is something "there" into this weird stuff. If this proves to be complete nonsense, I must admit I would never have seen such level of crafted crackpottery!
The full book with its clickable table of contents is available in one PDF at https://ayuba.fr/pdf/QWM.zip
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#373 by Alex_O on 03 Oct, 2020 21:26
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Upd, sorry, I need to think more, sorry
No, no Alex, you were right! The full book is indeed available for free in the section "books" on top of the URL you gave, split in 9 PDF files. They were created 15 and 16 September 2020 and I'm quite sure they were not there last time I checked… so either this is a coincidence, or Mr Reed heard of some discussion here and there…
..
About this incredible density and quality of such work (speaking of the form, not the substance as I don't have any opinion about the physics yet) I wonder if this is junk physics explained with garbage word salad, or if there is something "there" into this weird stuff. If this proves to be complete nonsense, I must admit I would never have seen such level of crafted crackpottery!
The full book with its clickable table of contents is available in one PDF at https://ayuba.fr/pdf/QWM.zip
Thanks for preparing the file, I have already looked at many pages in different files and am beginning to understand the basic ideas of Mr. Reed. I'll just say that I like the high level of preparation of the material in the book and presentations.
You can start your analysis of Mr. Reed's ideas with a short article https://www.academia.edu/11093756/Confinement_of_Light_Standing_Wave_Transformations_in_a_Phase_Locked_Resonator
Larry immediately reportsQuoteElectromagnetic resonant wave interactions in a phased-locked resonator at rest and in motion are compared. The origin of mass and inertia as a standing wave interaction in a phased-locked cavity as demonstrated in work by Jennison is reviewed and phase relationships illustrated. For matter (composed of resonant EM standing waves) in motion, the Lorentz contraction is interpreted as a physical wavelength compression due to variation in EM field energy density as measured by vacuum refractive index KPV. Dipole radiation emitted from a phase-locked resonator in motion is described. A graphical representation of Ivanov-LaFreniere standing wave transformations is shown. Experimental possibilities for potential phase conjugate wave phase-locked resonator development are discussed including inertia modification and propulsion.
However, I don't know what to do about it yet. To begin with, I started looking at Jennison's work (the file is attached) and suddenly realized that I did not understand what a phase-locked resonator is. The ideas about the radiation pressure of photons that have changed by the Doppler effect are somehow understandable to me, but I remember discussions with meberbs, for example here
https://forum.nasaspaceflight.com/index.php?topic=45824.msg1992196#msg1992196
or is it better here
https://forum.nasaspaceflight.com/index.php?topic=45824.msg1993307#msg1993307
But the phase-locked resonator seems to be very different, it has a tricky function - two em waves that move towards each other.QuoteFor a free-floating wave system consisting of two counter-propagating traveling waves in a phase-locked resonant cavity, application of an external force results in an imbalance of radiation pressure of Doppler-shifted waves causing the wave system to move as a whole in a stepwise series of velocity increments.
Pay attention to the term traveling waves. Shawyer also uses the term traveling waves in his explanations of emdrive in http://www.emdrive.com/dresden2018.pdf
He wrote directlyQuoteWhy are there no side wall forces? Thrust due to traveling waves not standing waves
But Shawyer never gives more detailed details of this physics (as well as the technical implementation).
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#374 by Mark7777777 on 04 Oct, 2020 02:52
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Larry Reed, a retired American aerospace engineer, author of the book Quantum Wave Mechanics (Booklocker 2020, ISBN 978-1634929646, also available here in PDF — Edit: sorry, contents + preface of the book only in this link)
has put a document online, entitled "EM propulsion drive": https://www.academia.edu/44118894/EM_propulsion_drive
I've just skimmed through very quickly. I noticed diagrams about Doppler shifts within a moving (accelerating) cavity.
Has anybody ever heard of Mr Reed? What do you guys think of the paper?
EDIT2: Chapters 1 to 7 of the book are available for free at https://www.academia.edu/44096967/extract_Quantum_Wave_Mechanics_Ch_1_7_pdf
Chapter 52 is supposed to deal with "antigravity"… but after extensive research the book is clearly unavailable from all possible online sources.
Hi, thanks for sharing about Larry's work, I found a download link for all chapters (16 files)
https://independent.academia.edu/LarryReed
..
Upd, sorry, I need to think more, sorry
Yes I'd also be interested to know meberbs thoughts on https://www.academia.edu/44118894/EM_propulsion_drive. -
#375 by flux_capacitor on 05 Oct, 2020 15:35
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Yes I'd also be interested to know meberbs thoughts on https://www.academia.edu/44118894/EM_propulsion_drive.
I'd like that too!
Let's begin with a remark about the 1st slide, because I thought immediately after opening the file that the figure represented a traditional EmDrive from the side, whereas it is not!
It's not a tapered closed cavity, it is a flat platform (in white) floating above the ground (parallel slanted segments at the bottom) and the greenish light section in-between is some kind of wide gravitational radiation sketched. There is a back and forth incident/reflected "graviton" beam between the flying (moving) platform and the (fixed) ground, but it's more of a side effect of Reed's "theory" that would be similar to a "gravitational ground effect" analog to the classical ground effect except the back pressure on the flying platform would not be aerodynamic but of gravitational nature. This idea is quite far-fetched and we should focus first on the first assumptions presented in the document instead.
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#376 by flux_capacitor on 05 Oct, 2020 16:28
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So here are slides #2 and #3. Notice that the resonator is of constant cross-section, different than Shawyer's EmDrives (which were constant cross-section resonators with an internal dielectric, then tapered frusta with or without internal dielectrics). But it is an RF resonant cavity nonetheless.
This example is NOT a propulsion system. It only shows the consequence, on wavelength of travelling EM waves, of a cavity accelerating due to an external force being applied (for example when one pushes on the cavity with his hand, inducing motion to the right in this case).
First, slide #2 shows the resonator at rest. The two counter-propagating travelling waves between each mirror or plate have exact same frequency and wavelength. They create a standing wave that has no repercussion on the inertia or momentum of the cavity whatsoever.
Then, the resonator is put in motion by an applied external force.
Slide #3 shows the behavior of the two counter-propagating travelling waves in this accelerated case, which are not the same anymore due to Doppler shifts. As the leading plate is escaping, the wave reflected backward is redshifted. Opposite situation on the approaching back plate, which reflects a blueshifted wave. Their combination gives a contracted moving standing wave.
Due to an external force being applied (no reactionless propulsion here!) the cavity experiences an acceleration a = F(ext)/m , and the incident/reflected wavelength difference is proportional to the acceleration.
This is mundane basic physics but I'd want to be sure there is no issue with these explanations before proceeding to assumptions about propulsion in subsequent slides.
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#377 by flux_capacitor on 06 Oct, 2020 13:44
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I find mentions of Roger Clifton Jennison (Wikipedia) back to EM Drive thread 7 and thread 9.
Actually SeeShells found Larry Reed's paper "Confinement of Light: Standing Wave Transformations in a Phase-Locked Resonator" back in July 2016!
A few important papers from Jennison attached. This is one of the main bases of Reed's approach. Jennison models inertia with macroscopic phased-lock resonators put in motion. Doppler shifts create more radiation pressure on one side if the cavity is put in motion. There is an interesting staircase diagram also. Jennison made several experiments and published many papers on the subject through several decades.At first I thought there was more radiation pressure exerted on the back mirror of the resonator put in motion, that would oppose acceleration (what we feel as inertia when we push on a massive object); but now I wonder if this is the opposite i.e.more radiation pressure occurs on the front mirror, that keeps the cavity in infinite motion at constant velocity after the external force initially applied has ceased (what we see as the inertial trajectory of an object without friction, e.g. in deep space vacuum).
EDIT: Correct answer selected above, explanation in my next message.
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#378 by Alex_O on 06 Oct, 2020 19:34
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At first I thought there was more radiation pressure exerted on the back mirror of the resonator put in motion, that would oppose acceleration (what we feel as inertia when we push on a massive object); but now I wonder if this is the opposite i.e. more radiation pressure exerted on the front mirror, that keeps the cavity in infinite motion at constant velocity after the external force initially applied has ceased (what we see as the inertial trajectory of an object without friction, e.g. in space vacuum). If someone can clarify this it would be much appreciated.
I am still studying the issue that the forces of radiation pressure in the resonator strongly depend on the resonance conditions of the EM wave (with the resonator). If the Doppler effect changes the frequency of the wave, then the wave "falls out of resonance", and the pressure force of the EM wave at the ends of the resonator will be much less.
Since the conductivity (transparency) of a rectangular waveguide for long EM waves is less than for short wavelengths, and there is a cutoff frequency when long waves cannot pass through the waveguide, then perhaps blue and red waves (due to the Doppler effect) are simply created at the end walls are different forces of radiation pressure. And the side walls (if the resonator is somehow short) - they just do not harm.
Example.
1. The resonator is at rest, there is EM resonance. It contains a "white" (normal) wave, which creates standing waves.
2. The resonator is moved by an external force to the right, which is applied as a short pulse, 10 picoseconds long, once. (the box with photons got kicked from the left)
3. The left wall first reflected the "white" waves, since the external force kicked the resonator a little later.
4. The white wave falls on the right wall (which is already moving to the right) and is reflected by the red wave.
5. But the red wave (longer) simply cannot pass through the waveguide / resonator, since its frequency is lower than the cutoff frequency. (I greatly exaggerated this point for clarity).
What to do with this next - I do not understand yet.
Maybe physical time is important? The energy of the red wave will somehow linger in the region of the right wall for several nanoseconds. At this time, EM forces will act on the right wall, and these forces will "long-long-long-long" press on the right wall. As a result, the resonator will receive additional acceleration to the right. The red Wave has done a great job in this "long, long" physical time.
In other words, the end walls of the resonator can be like a trap for photons, the walls seem to catch photons, they seem to "stick" to the end walls for a short time, and this stickiness is somehow very different for white, blue and red photons.
And if a photon "stuck" to the end wall for two moments, then it is like a bulldozer, a tractor, pushing the wall forward. It sounds fantastic, but we know about group velocity, about subtle effects on conductive surfaces. And we see how people surfers catch the wave and fly on the crest of the wave. They "stick", "catch" on the wave crest.
sorry, I tried to study the motion of an EM wave in a resonator at a time interval less than 1 ns. -
#379 by TheTraveller on 07 Oct, 2020 10:19
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The necessity of differential Doppler shift as discussed by Roger in his 2013 IAC paper. Section 2.
http://www.emdrive.com/IAC13paper17254.v2.pdf
Roger shares, for the 1st time in his soon to be shared 2020 IAC paper, details & numbers for the precursor small end forward external force & duration to cause the pecursor Doppler shift required to engage self sustained Motor Mode.
As far as I'm aware no EmDrive builder has ever used a precursor external force during their testing, despite it being clear from 2013 such a force was required to generate the differential trigger Doppler shifts.
