Quote from: JohnFornaro on 08/01/2014 12:37 amI wouldn't dream of posting here....I can understand the skepticism...However the experimenters are all NASA scientists.What is the problem? are you a better scientist John F? Or do you think the authors should be stripped of their NASA posts?Maybe we should calm down and investigate further?Heavens!
I wouldn't dream of posting here....
This discovery came about because Shawyer was trying to explain the thrust generated by the microwave transmitters on satellites which exceeded what was expected and required additional fuel to correct.
OK, here's an idea. The resonant cavity's purpose is to produce standing waves, right? So, basically it's a precise arrangement of conducting plates which reflect EM waves back and forth. For some reason, this reminds me of a "macro" Casimir cavity, just on a different scale and with "real" photons. So, what if.. this EM drive acted (by coincidence) as some weird form of "macro" Casimir cavity and its specific shape (accidentally) produced a preferred vector, working with real photons? I seem to remember that specific geometries of Casimir cavities were calculated to be able to produce a preferred vector of motion. I didn't find that piece of info yet again, or perhaps I remember wrongly. Maybe someone else knows better?
Quote from: mlindner on 08/03/2014 03:31 amI was mainly looking for a short description of a major issue with the experiment that I can feed to people to prompt them to engage their brains for a minute rather than shoveling the bull**** down their throats without thinking. After that some discussion can be sparked to realize the issues at hand.i think there are two major issues.1. the signal is very small. this makes it easy for uncontrolled for unanticipated spurious signals to get in there. critic can claim this is what caused it all day long. it's hard to disprove.2. in this experiment it appears the control test article got the same signal. I do not think this is as damning as it could be because of the signals found by other researchers with (similar devices of differing design details.) E.G. Dr Woodward's design is a solid state peizoelectric stack. he gets a thrust signal. Dr White has a capacitor and coil ring and gets thrust signals. the Egyptian girl uses a moving casimir mirror and gets a thrust signal. The Chinese use Shayer's design as a starting point and get a much stronger thrust signal than he did or NASA testing got.
I was mainly looking for a short description of a major issue with the experiment that I can feed to people to prompt them to engage their brains for a minute rather than shoveling the bull**** down their throats without thinking. After that some discussion can be sparked to realize the issues at hand.
Quote from: ChrisWilson68 on 08/02/2014 11:05 pmThey are made by not having any preconceived ideas about applications.How do you look for a new law in physics?A friend shared this with me. It makes the point well.and Visa versa
They are made by not having any preconceived ideas about applications.
The problem is that the article linked is not a scientific paper, but a clearly preliminary technical report, the typical "hat on the seat" (copyrighted by me ) paper required to ensure to be the first IF a sensational result is confirmed in order to get an high citation index in the future.
No, the NASA folks shot themselves in the foot with this unclear NTRS abstract, which is very misleading once you have read the complete paper, as birchoff and I did. Birchoff is right, the paper is only $25, and now it's very clear that even ArsTechnica only read the NTRS abstract and didn't download the complete paper before writing and publishing their biased article. Very poor journalism.The fact is (and the NTRS abstract does not explain this): Eagleworks tested one tapered (frustum) cavity, aka Shawyer's EmDrive; and two Cannae drives which are also asymmetric but different resonant cavities. The Cannae drive is said to work on a purported different principle than the EmDrive, according to its inventor Guido Fetta (a net Lorentz force imbalance of electrons upon top vs bottom wall of the cavity). According to this purported working principle, one Cannae drive had radial slots on its rim as required by Fetta in order to produce net thrust, and the second Cannae drive didn't have those slits and was intended to be a "null test device". But the Cannae null test article… also produced net thrust (20 to 40 µN of net thrust depending of the forward or backward direction).We're talking of net thrust because of course the setup was also tested with a null 50 ohm load connected, in order to cancel the effect from the drives and detect any detect any spurious force due to EM coupling with the whole apparatus (which exists, at 9.6 µN) and this "null" spurious force was evidently subtracted from any thrust signal due to the drives then tested on the pendulum. So the fact that the Cannae null test article produced a net thrust doesn't imply the experiment was screwed up. It rather showed that the radial slits required by Guido Fetta for propulsion are not the reason for the thrust, and another theoretical explanation is needed. Absolutely no news on the websites, including wikipedia, actually reports correctly this information.We can go further by pointing another underestimated yet important fact of those NASA experiments: all tests articles (the EmDrive version, the Cannae drive version, and even the Cannae "null test" version) had a dielectric embedded within. This is a hint for a different theoretical explanation involving EM fields, proper acceleration, mass fluctuation and dielectrics. Maybe Mach effects (due to Mach's principle), as supposed by Woodward and Fearn within the GR theory, or within a scalar-tensor theory of gravity according to Minotti. As for Sonny White, he talks about compressible quantum vacuum fluctuations, but there are flaws about this conjecture regarding the thrust magnitude observed.
Quote from: FlyingMoose on 08/03/2014 04:43 amThis discovery came about because Shawyer was trying to explain the thrust generated by the microwave transmitters on satellites which exceeded what was expected and required additional fuel to correct.This would really make an interesting subject to read or a comparison point to read up on.who you be able to supply a link or a paper?
It seems much confusion has arisen here. I have been reading on the Polywell forums that firstly the business with the Null article is not a concern, what you are seeing is an ill chosen abstract. Please see the quote below for more detail.
Looking at the very small amount of thrust generated I suspect measurement error or a problem with how the testing was set up.Correct me if I have this wrong but 30 to 50 micro Newtons of thrust (.000030 to .000050 Newton) equates to about . .003 to .005 grams of thrust. This tiny amount of force could easily be generated by air currents around what must be a warm to hot test article and could explain why the 'null' test article also produced thrust.According to the NASA document http://ntrs.nasa.gov/search.jsp?R=20140006052 all testing was done in a vacuum chamber 'at ambient atmospheric pressure'.I sure hope I'm wrong!!! Charlie
Last year a Chinese team built its own EmDrive and confirmed that it produced 720 mN (about 72 grams) of thrust, enough for a practical satellite thruster. Such a thruster could be powered by solar electricity, eliminating the need for the supply of propellant that occupies up to half the launch mass of many satellites. The Chinese work attracted little attention; it seems that nobody in the West believed in it.
Quote from: Star One on 08/03/2014 07:47 pmIt seems much confusion has arisen here. I have been reading on the Polywell forums that firstly the business with the Null article is not a concern, what you are seeing is an ill chosen abstract. Please see the quote below for more detail. If the experiments were actually done at atmospheric pressure none of that matters. It's clear from the paper that at least some of the tests were (see fig 22). That fact that it isn't clearly stated for each test is a major flaw in the paper regardless of the results, and strongly suggests the paper wasn't rigerously reviewed.I don't understand why you think the quoted post would "clear up confusion", it looks like a hand wavy rationalization to me. To most scientists, a "null" that produces the predicted effect would be a strong hint to look for experimental error, not new physics.
Quote from: hop on 08/03/2014 08:19 pmQuote from: Star One on 08/03/2014 07:47 pmIt seems much confusion has arisen here. I have been reading on the Polywell forums that firstly the business with the Null article is not a concern, what you are seeing is an ill chosen abstract. Please see the quote below for more detail. If the experiments were actually done at atmospheric pressure none of that matters. It's clear from the paper that at least some of the tests were (see fig 22). That fact that it isn't clearly stated for each test is a major flaw in the paper regardless of the results, and strongly suggests the paper wasn't rigerously reviewed.I don't understand why you think the quoted post would "clear up confusion", it looks like a hand wavy rationalization to me. To most scientists, a "null" that produces the predicted effect would be a strong hint to look for experimental error, not new physics.My overall view is this is going to have wait for the further round of tests in the fall of this year, it looks like at this time there are just too many possible issues with this as it stands. It sounds like what they are planning next is either going to make or break this whole thing.
Quote from: Star One on 08/03/2014 08:41 pmQuote from: hop on 08/03/2014 08:19 pmQuote from: Star One on 08/03/2014 07:47 pmIt seems much confusion has arisen here. I have been reading on the Polywell forums that firstly the business with the Null article is not a concern, what you are seeing is an ill chosen abstract. Please see the quote below for more detail. If the experiments were actually done at atmospheric pressure none of that matters. It's clear from the paper that at least some of the tests were (see fig 22). That fact that it isn't clearly stated for each test is a major flaw in the paper regardless of the results, and strongly suggests the paper wasn't rigerously reviewed.I don't understand why you think the quoted post would "clear up confusion", it looks like a hand wavy rationalization to me. To most scientists, a "null" that produces the predicted effect would be a strong hint to look for experimental error, not new physics.My overall view is this is going to have wait for the further round of tests in the fall of this year, it looks like at this time there are just too many possible issues with this as it stands. It sounds like what they are planning next is either going to make or break this whole thing.Nothing will ever break it. The tests will fail to show convincing evidence of anomalous thrust, and the proponents of the various reactionless drives will come up with rationalizations for it and explain how they're working on new versions that will fix the problems. It will continue without end.