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#580 by Rodal on 15 Sep, 2014 12:07
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@Rodal
I think the answer to your thrust descripancy between the Cannae and the Tapered Frustum devices may be partly answered by the size of the dielectric. According to the pictures and comsol models in the paper the size of the dielectric in the Cannae device has to be much smaller than the die electric in the Tapered Frustum.
Well, the numbers I posted (I am now putting everything in uN, as people may not have noticed the difference between mN and uN, and I am adding the Woodward-Effect devices) (see slide 40 of http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf ):
Shawyer/SPR Ltd.'s microwave device:
THRUST = 16000 to 170000 uN
SPECIFIC FORCE = 0.02 to 0.4 N/kW
______________________________
Boeing/DARPA device:
THRUST = 20 to 110 uN
SPECIFIC FORCE = 1 to 20 N/kW
______________________________
Cannae Testing:
THRUST = 40 uN
SPECIFIC FORCE: 0.0014 N/kW
______________________________
Tapered (Frustum) Cavity Testing:
THRUST = 50 to 90 uN
SPECIFIC FORCE= 0.003 N/kW to 0.0054 N/kW
______________________________
(?)Woodward-Effect device tested in 2004:
THRUST = 4000 uN
SPECIFIC FORCE= 0.4 N/kW
______________________________
Paul March Woodward-Effect device tested in 2005:
THRUST = 3000 uN
SPECIFIC FORCE= 0.3 N/kW
______________________________
Show little difference between the performance of the Cannae and the Frustum (Tapered Cavity) devices when compared to the other devices: both of them have Specific Force numbers much lower than the Shawyer/SPR Ltd and Boeing/DARPA devices
and the performance of the Cannae and the Frustum (Tapered Cavity) devices is also much inferior to the previous tests at NASA Eagleworks performed on the Paul March Woodward-Effect device.
If we have to ignore the very high thrust forces of the Shawyer/SPR Ltd because those numbers are untrustworthy (not from NASA), and if we have to ignore the very high specific force of the Boeing/DARPA device because its thrust force was not a rectangular pulse, but instead an impulse and hence not suitable for steady-state operation, the clear winner both in thrust force and specific force are the Woodward-Effect devices, they have orders of magnitude greater thrust force and specific force than the lousy-performing Cannae and Frustum (Tapered Cavity) devices recently tested.
So, forget about Microwave Resonators and go back to Woodward-Effect devices ?
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#581 by Rodal on 15 Sep, 2014 12:19
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@Rodal
.....
As for your question about the thrust and specific force numbers reported in the Deck for Shawyer's EmDrive. It is my understanding from second and third hand information that while Dr. White originally attempted to replicate Shawyer's device, they failed to get positive results. ...
So if the information is accurate then its most likely that the numbers on slide 40 of that deck are coming from one of Shawyer's papers or the Chinese papers (I have yet to double check that).
Thank you for checking this.
I agree with your reasoning. I am still not 100% sure though, because:
A) Dr. White writes in that slide that he will ignore the Chinese data, so why would he show the Chinese data when he writes that he is simultaneously going to ignore it?
and
B) If the Shawyer data is from experiments done at Shawyer or elsewhere (not at NASA), why show such NASA-unverified Shawyer -data mixed together in a deck of slides with actual NASA data for other devices?
Kind of confusing to me...
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#582 by Jossarian on 15 Sep, 2014 13:13
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If we could use nuclear rockets, other choices would be availabe for our propulsion needs, but sadly the nuclear propulsion venue is not available to the US space program due to political issues we all know of, unless of course a fusion power breakthrough shows up on our doorsteps...
Here you go...
http://www.forbes.com/sites/jeffmcmahon/2014/01/04/doe-mentions-technology-behind-the-home-nuclear-reactor-in-funding-opportunity/
http://climate.nasa.gov/news/864/
Isn't NASA’s Langley Research Center working on LENR reactors already?
It is also possible to use something like this:
http://arxiv.org/abs/1305.3913v3
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#583 by JohnFornaro on 15 Sep, 2014 13:15
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As someone said before and in agreement on the experimentalist side of things...
Why doesn't someone get a bloody big 100Kw setup of the devices discussed and measure thrust?
We wouldn't need vacuum chambers or any nonsense.
Why not?
Why not? Because......why not build a 33 kilowatt device, place it on an old fashioned weighing scale, and wow the world with a whole pound of thrust?
Seriously, this time:
The cost and difficulty of scaling to that degree is prohibitive. -
#584 by Rodal on 15 Sep, 2014 14:19
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This is the text for Paul March Woodward-Effect device tested in 2005: (see slide 40 of http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf )
The test unit was run at 2.13 MHz, yielding an AC electric field of ~20kV/m, and an AC magnetic field of ~27 Gauss.
• Based on the input parameters, the QVPT thrust prediction was 0.63 mN [630 uN]
• The observed thrust was +/- 0.89 mN [890 uN]
The test unit was run at 3.8 MHz yielding an AC electric field of ~20kV/m, and an AC magnetic field of ~48 Gauss.
• Based on the input parameters, the QVPT thrust prediction was 2.79 mN [2790 uN]
• The observed thrust was +4.91 to -1.96 mN [+4910 uN to -1960 uN] as measured via a 4900 mN (500gf) load cell
As can be seen to the right, the thrust signal is very clear when the unit is excited.
~3 mN Thrust [3000 uN]
Specific Force ~0.3N/kW
________________________________
Notice:
1) The Thrust force was NOT measured with NASA's inverted pendulum, but instead with a 4900 mN (500gf) load cell. If you see Dr. Woodward's paper, you will see that Dr. Woodward abandoned initial (hanging) pendulum testing in favor of load cell testing, because he noticed that pendulum testing introduces inertial artifacts from the pendulum itself. My opinion : this makes sense to me.
2) There is excellent agreement (from an engineering viewpoint) between Dr. Woodward's prediction for thrust and the experimental measurements.
3) << the thrust signal is very clear when the unit is excited>>
4) Based on the tested numbers, I don't understand the emphasis on the (Cannae and Frustum Tapered-Cavity) Microwave devices as their performance is very lousy in comparison. -
#585 by JohnFornaro on 15 Sep, 2014 14:27
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As someone said before and in agreement on the experimentalist side of things...
Why doesn't someone get a bloody big 100Kw setup of the devices discussed and measure thrust?
We wouldn't need vacuum chambers or any nonsense.
Why not?
Do we need to go to 100kW ? Does the Shawyer/SPR Ltd.'s device have a thrust orders of magnitude (400 to 4250 times higher) higher than Cannae device -as quoted by Dr. White- yes or no?
Ok, start at 1KW then 10KW then 100KW...
The point is its much easier (I think) to construct higher power devices than to detect low thrust levels.
If a 1KW device was to slide down an air-track then the world would change...
OK I completely agree with you and JohnFornaro on that. Now,
Does the Shawyer/SPR Ltd.'s device have a thrust orders of magnitude (400 to 4250 times higher) higher than Cannae device -as quoted by Dr. White- yes or not? Did Dr. White's lab test the Shawyer/SPR Ltd.'s device, yes or not?
Can someone in this forum answer that, please
?
The copper Truncated Frustrum thingy looks like Shawyer's device. Glad that you agree with me, BTW.
It would be nice to read more of Rodal's analysis of the testing mechanism.
The theory of how this device works is changing. Here's some forum history:QuoteQuote
EM-Drive is not fake science. They have a WORKING prototype and are moving towards a flight test in 2009. www.emdrive.com. This uses actual physics and obeys all the convervation laws.
I am NOT impressed by this site. It states that just like a laser ring gyro is a closed system and can measure rotation rate, this drive is a closed system that can produce force. Newton and all have NO problem with a closed system measuring rotation rate. No need to introduce Special Theory effects to explain this. Explaining away the closed system problem by using the laser ring gyro as an analogy tells me these people are incorrect.
However I do hope I am wrong and they produce a really nice rocket engine someday. I for one will not be investing my money in this technology.
Danny Deger
P.S. Maybe there is some change of momentum of the photons that balances the change of momentum of the rocket. This would make the device not violate the law of the conservation of momentum.
I took me a while to understand how it works. There is a basic property of a waveguide that describes how the group velocity of a wave changes as the size of the waveguide changes. For the em-drive it is this that creates the force imbalance on the end walls of the cavity. In terms of momentum, if there are two equal masses and the total momentum p=p1-p2 then p is non zero when the velocities of the particle colliding at each end of the waveguide differ. The slope of the walls of the cavity ensure the collisions with the walls along the length result in a nonlinear force ie: the differing group velocities along the length of the sloping cavity ensure the particles don't just bounce around inside the cavity canceling each others forces totally out. One uses the law of relativistic velocity addition to see that there is forward motion when the thruster is viewed by an outside observer (thus an open system).
To illustrate:
If one fires two opposing canons within a closed box the impact of the canonballs against the walls will cancel out to result in zero motion. If either the velocity or the mass of one of the balls changes en-route to the wall then the impacts will not cancel out and there will be motion. The trick then is to deal with the lost mass or velocity. It has to have gone somewhere.
From the point of view of momentum; The em-drive looks at the change in velocity whereas the woodward drive looks at the change in mass. The both deal with the imbalance in different ways. EM-drive uses the properties of waveguides and relativity whereas woodward's drive uses machian mass fluctuations and a rectifier.
When one accounts for the energy absorbed into the system to create the motion then one retains conversation of energy. Same for momentum.
So I think I understand. Took me a while but I think I'm there. And it is basic physics! It USES newton laws. It just needed a different perspective.
Nathan:
A major problem with Shawyer’s waveguide explanation is that his theoretical proof does not provide an explanation for the magnitude of the reaction forces reported. Photon rockets of any stripe with only several hundred watts of input power can't generate thrusts measured in milli-Newtons. Instead they can only produce pico to nano-Newtons of thrust from their local power supplies, unless they are also inadvertently tapping into a higher dimensional energy manifold as do Woodward's devices with the cosmologically derived gravinertial field.
However, Shawyer first has to replicate his posted video experiment in a hard vacuum (<1x10-6 Torr) and get the same results, thus precluding possible ion wind or cooling fan generated thrusts before we worry too much about his proposed theoretical approach. If he does get the same reported thrust in a vacuum though, then my bet is still on Sonny White's QVF explanation being more accurate than Shawyer’s.
BTW, as noted by GI-Thruster, I need to find the time and resources to replicate my Mach-2MHz experiment and/or exercise my new MLT-2009 test article in a hard vacuum, before we can take its results to be anything more than strongly suggestive that M-E based MLTs work as advertised. Alas, that next step for me has proven problematic so far...
What does the device push upon? Personally, I'm disregarding the "free energy" aspect of the device, and am more concerned with the conservation of momentum.So what do you consider “substance” in regards to proving these observed M-E effects are REAL? Supporting experimental data from two or more different sources used to be considered substantiating support, but apparently that is no longer the case in 2009. So what will it take to prove the point to you and the rest of the skeptics in the world that the M-E or its QVF cousin is real and usable?
I am not a sceptic, I would be *happy* if someone will prove that 3rd law of Newton can be worked around.
It can be the case that the idea, being rather radical, does require verification by more than one team. Extraordinary claims do require extraordinary evidence, in this case, reproduction of the effect by multiple teams.
Do not assume that "they" (meaning scientific community) have ill intentions. No amount of complaining that "they" don't take it seriously would help. Ony more independent verifications will.
Firstly, please stop asserting that M-E gets 'around' Newtons third law any more than a game of tug-of-war does. The M-E reacts against the rest of the universe, period. While I understand thats a bit big of a concept for some folks, honestly though, it shouldn't be for anybody who has moved beyond the idea that anything outside our solar system is just little light bulbs on a big sphere.
By what mechanism is it reacting against the rest of the universe? Why do other devices not react with the rest of the universe like this? Why is this one special? How can it instantaneously signal the rest of the universe to react? Saying it is so doesn't make it so.
I'm not explaining anything. I'm trying to understand the concept here. My earlier post about how the non-exhaustive list simply does not serve to explain the theory still holds true.
Every year since around 2009, the theoretical rabbit hole of explanation about how this device works gets deeper and deeper, and thrust levels do not appear to be rising.
If there's a skunk works somewhere working on this, and it is Top Secret then so be it.
Just for more reading, as well as an illustration of the Truncated Frustrum thingy. The Chinese have expressed interest in this technology, and seem willing to invest:
http://www.technovelgy.com/ct/Science-Fiction-News.asp?NewsNum=1898
http://blog.wired.com/defense/2008/09/chinese-buildin.html
An earlier explanation of the EmDrive suggested that "group velocity" was an operating principle. From my post on that Propellantless Propulsion thread on April 21, 2009, 03:19:58 PM:
IAC- 08 – C4.4.7. which I’ll call “The Theory Paper”.
Group velocity is the speed with which the modulation of the wave propagates through space. It is not the speed which any particles propagate. It is here that the paper falls apart for me, and is precisely the point in the cannonball analogy above where the analogy falls apart. All of the cannonballs’ momentii (if that’s the word) will cancel out, unless the mass of a cannonball changes. Then the analogy can propel itself forward. But there’s no explanation of what it is that changes about the cannonballs to provide momentum.
Group velocity is dw/dk, where w is the wave’s angular frequency and k is the wave number. I don’t see how this affects momentum.
In blazotron’s analysis of the theory paper, he states: “Then [Shawyer] states, completely without support, that the force imparted by a wave with group velocity vg is 2nhfA*(vg/c). Nowhere in the text is it explained why we should be using the group velocity of the wave to calculate force.” I think blazeotron is somewhat incorrect in stating where in the text is this explained. The author alludes to:
CULLEN A.L. ‘Absolute Power Measurements at Microwave Frequencies’ IEE proceedings Vol 99 Part IV 1952
Thanks to MikeGi:
More on Shawyer:
http://www.assassinationscience.com/johncostella/shawyerfraud.pdf
Note how Shawyer's "Theory" original paper:
http://www.newscientist.com/data/images/ns/av/shawyertheory.pdf
Differs from the "Theory" paper now on his website:
http://www.emdrive.com/theorypaper9-4.pdf
Thanks to my digging:
http://www.rexresearch.com/shawyer/shawyer.htm
http://www.rocketeers.co.uk/?q=node/330
EmDrive at work:
See also here:
http://forum.nasaspaceflight.com/index.php?topic=14423.0
Thanks to 93143:
http://www.emdrive.com/yang-juan-paper-2012.pdf
http://forum.nasaspaceflight.com/index.php?topic=13020.msg978642#msg978642
Finally:John - You're grasping at straws. The topic is Propellantless Field Propulsion and application. The test stand has no bearing on the topic beyond giving assurances that the thrust measurements were accurately made. Any good test stand will do, even a pendulum.
Aero: ...
The common wisdom is that EM drive does not work. In the case of Woodward's work, and probably Shawyer's as well, the test stand is almost as important as the tested device itself, since the expected forces are thought to be very low in the experiments demonstrated.
Woodward and Paul March have gone to great lengths to account for spurious outside signals, and even now, can barely ascertain the output of his device from noise.
A pendulum will most assuredly not work. ... The measurement of the forces is key, until such time as they float one of these devices out on the conference room table. ...
The test stand is very important. If I might repeat myself: It would be nice to read more of Rodal's analysis of the testing mechanism.
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#586 by Rodal on 15 Sep, 2014 14:47
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The test stand is very important. If I might repeat myself: It would be nice to read more of Rodal's analysis of the testing mechanism.
@JohnFornaro
I completely agree with your statement <<The test stand is very important. >>. There are pendulum dynamic forces to take into account, as well as nonlinear coupling between swinging and torsional modes of oscillation. I started to discuss this in detail but the thread got deviated into controversial-theoretical explanations. Paul March was forthcoming with data. My last post dealing with the test stand, I made some calculations (stiffness and natural frequency of swinging mode) based on my interpretation and I asked for confirmation. There have been so many posts dealing with controversial-theoretical explanations that that particular post got buried. Perhaps I should re-post it.
My plan is the following: once Paul March has a chance to look at it, and to verify my understanding, then I can proceed to show my transformation of axes (rigid-body axes for the drive supported on the inverted pendulum compared to the fixed suport axes located at the bottom support of the inverted pendulum arm), and then my computation of a Lagrangian, and then the resulting equations of motion (showing coupling of torsion with swinging modes, and parasitic motions) from differentiating the Lagrangian.... -
#587 by Rodal on 15 Sep, 2014 15:24
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Quote
...Newton and all have NO problem with a closed system measuring rotation rate. ...
Danny Deger
Excellent point by Danny. I agree. Feynman has a trick question regarding conservation of momentum (on the rotational effect of an electromagnetic force) on his Lectures on Physics classic. -
#588 by Rodal on 15 Sep, 2014 15:30
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To put this in fewer words:
If the drive's support platform (sitting on the inverted pendulum) does not stay horizontal when the inverted pendulum arm swings off-center, then this might be a problem, as it leads to coupling of swinging and torsional modes, and therefore to parasitic modes. That's why Prof. Martinez-Sanchez at MIT designed (with students for their S.M. theses) his inverted pendulum's stand to stay horizontal at all times, even for swinging off-center motion of the inverted pendulum arm. -
#589 by Rodal on 15 Sep, 2014 17:50
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Referring to the following Paul March's article http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=31119.0;attach=496011
It is clear that
A) the "2004 Test Article" and the "2005 Test Campaign" referred to in slide 40 of Dr. White's presentation http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf ) are exactly the same as Paul March's tested devices in 2004 and 2005 in (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=31119.0;attach=496011)
B) the "2004 Test Article" and the "2005 Test Campaign" referred to in slide 40 of Dr. White's presentation http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf ) were NOT tested in Dr. White's NASA inverted torsion pendulum. Instead they were tested by Paul March using a load cell.
Since it also appears that the Shawyer/SPR Ltd. data labeled as "Microwave Thruster Device" in slide 40 of Dr. White's presentation http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf ) were NOT tested in Dr. White's NASA inverted torsion pendulum, but instead they were tested elsewhere, we must separate the performance of devices tested elsewhere from those tested with Dr. White's NASA inverted torsion pendulum as follows:
Experimental data not obtained using Dr. White's NASA inverted torsion pendulum
______________________________
Shawyer/SPR Ltd.'s microwave device:
THRUST = 16000 to 170000 uN
SPECIFIC FORCE = 0.02 to 0.4 N/kW
______________________________
Paul March Woodward-Effect device tested in 2004:
THRUST = 4000 uN
SPECIFIC FORCE= 0.4 N/kW
______________________________
Paul March Woodward-Effect device tested in 2005:
THRUST = 3000 uN
SPECIFIC FORCE= 0.3 N/kW
______________________________
******************************
Experimental data obtained using Dr. White's NASA inverted torsion pendulum
Boeing/DARPA device:
THRUST = 20 to 110 uN
SPECIFIC FORCE = 1 to 20 N/kW
______________________________
Cannae Testing:
THRUST = 40 uN
SPECIFIC FORCE: 0.0014 N/kW
______________________________
Tapered (Frustum) Cavity Testing:
THRUST = 50 to 90 uN
SPECIFIC FORCE= 0.003 N/kW to 0.0054 N/kW
______________________________
It is evident from the above:
A) The thrust force measurements performed elsewhere are 33 to 8500 times greater than the thrust measurements using Dr. White's inverted torsion pendulum experiments.
B) It is interesting that different devices (Boeing/DARPA compared to the microwave devices) although they have specific forces differing by a large factor of 1000 times, have approximately the same thrust force measurements in Dr. White's inverted torsion pendulum.
If we have to ignore the very high thrust forces of the Shawyer/SPR Ltd because those numbers are untrustworthy (not from NASA), and if we have to ignore the very high specific force of the Boeing/DARPA device because its thrust force was not a rectangular pulse, but instead an impulse and hence not suitable for steady-state operation, the clear winner both in thrust force and specific force are the Woodward-Effect devices, they have orders of magnitude greater thrust force and specific force than the lousy-performing Cannae and Frustum (Tapered Cavity) devices recently tested.
However:
Paul March's Woodward-Effect devices were tested in a completely different set-up (using a load cell instead of an inverted torsion pendulum).
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#590 by Rodal on 15 Sep, 2014 17:59
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a riddle wrapped in a mystery inside an enigma
Since Paul March's Woodward-Effect tests show thrust forces and specific forces two orders of magnitude larger than those measured for the Cannae and the Frustum (Tapered Cavity) microwave devices,
Why haven't Paul March's Woodward-Effect devices been tested in NASA/Dr. White's Eagleworks inverted torque pendulum and reported?
Wouldn't they have served as an independent control purpose of the measurements? It would have been helpful to have the same device (Paul March's) tested in two different testing set-ups (in inverted torsion pendulum to compare with the previous load cell measurements ) -
#591 by aero on 15 Sep, 2014 18:07
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Quote
Paul March's Woodward-Effect devices were tested in a completely different set-up (using a load cell instead of an inverted torsion pendulum).
Maybe Paul March would test the Tapered (Frustum) Cavity using his set-up. That should also work to provide valid comparison between the two devices. -
#592 by Rodal on 15 Sep, 2014 18:49
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Quote
Paul March's Woodward-Effect devices were tested in a completely different set-up (using a load cell instead of an inverted torsion pendulum).
Maybe Paul March would test the Tapered (Frustum) Cavity using his set-up. That should also work to provide valid comparison between the two devices.
There is also a need to verify the reliability of the much publicized measurements already conducted with NASA's Eagleworks inverted torsion pendulum. A NASA measurement carries a prestige (in the media) much higher than a measurement conducted at other places. Three different devices (Boeing/DARPA, Cannae and Frustum), that have specific forces differing by a factor of 1000 give approximately the same experimental measurement range of thrust force. A control is needed. Paul March's previously load-cell-tested Woodward-Effect devices would serve as such a control for the thrust measurements. If Paul March's measurements would be independently verified at NASA that would also carry significant prestige for Dr. Woodward's long-running efforts. -
#593 by JPLeRouzic on 15 Sep, 2014 18:56
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@Rodal: My feeling is that you try to find too much meaning in this whole thing. After all, there is no scientific or engineering breakthrough described in the Dr White paper, just a report on some exotic experimentations with anomalous results. I see it as some "food for thought" paper. Indeed as Paul March said, there is a "pay the bills" aspect intended for NASA managers and certainly not for scientists. This gives a specific style to the writing, which you would not find in a more traditionaly formated paper. Every organisation has its own culture and quirks.
Why haven't Paul March's Woodward-Effect devices been tested in NASA/Dr. White's Eagleworks inverted torque pendulum and reported?
If people think there is some ongoing conspiracy or that scientific breakthrough about interstellar travel has been achieved, it's entirely different topics from EMDrive purpose (or btw Cannae) which aims only as replacing auxiliary propulsion systems on satellites. -
#594 by RotoSequence on 15 Sep, 2014 19:02
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If people think there is some ongoing conspiracy or that scientific breakthrough about interstellar travel has been achieved, it's entirely different topics from EMDrive purpose (or btw Cannae) which aims only as replacing auxiliary propulsion systems on satellites.
You can't separate replacing auxiliary propulsion in satellites and interstellar travel; imparting delta-V without consuming/expelling reaction mass opens up the possibility of continuous acceleration in steady state operation. -
#595 by Rodal on 15 Sep, 2014 19:09
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@Rodal: My feeling is that you try to find too much meaning in this whole thing. After all, there is no scientific or engineering breakthrough described in the Dr White paper, just a report on some exotic experimentations with anomalous results. I see it as some "food for thought" paper. Indeed as Paul March said, there is a "pay the bills" aspect intended for NASA managers and certainly not for scientists. This gives a specific style to the writing, which you would not find in a more traditionaly formated paper. Every organisation has its own culture and quirks.
Why haven't Paul March's Woodward-Effect devices been tested in NASA/Dr. White's Eagleworks inverted torque pendulum and reported?
...
@JPLeRouzic
There is not just one paper.
There is a series of papers describing experimental results, in several countries, over at least two decades, as I have been discussing .
A) There is a claim that there can be rocket propulsion produced without on-board propellant and without an outside force propelling it (i.e. solar propulsion, electrodynamic tethers, etc.)
B) Furthermore, unconventional physics are proposed as an explanation (1) [Dr. White] a MagnetoHydroDynamics model for the quantum vacuum, 2) [Prof. Woodward] an unconventional Mach effect resulting in an “impulse” mass transient term and a second always-negative “wormhole” mass transient term, or 3) [Prof. Brito] a Minkowski instead of an Abraham stress tensor explanation without addressing "hidden momentum" (to name three different explanations that have been proposed).
I find those claims interesting, perplexing and worth investigating. If you are not interested in such an investigation, and you are not interested in the other papers, you are free to pursue your own interests and/or "quirks"
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#596 by wembley on 15 Sep, 2014 19:18
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Here is an article with a more accepting slant. Still has errors but what can you do. The tests were NOT performed in vacuum.
http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive
I have been trying to find out whether some of the tests were preformed in a vacuum. From the paper, it sounds as though some of them were not -- but why have the detailed description of the evacuation process if none of them were? Can anyone shed any light?
Also, my understanding is that this technology could fit on a cubesat, presumably that would be a fairly cheap test?
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#597 by wembley on 15 Sep, 2014 19:23
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I, for one, am glad if the NASA team's test results announcement has created a flutter. At least this will encourage more experts to get involved in coming up with either a definitive proof or disproof on this matter. At least one way or the other, the matter can then be settled.
It's already considered settled by mainstream science: there is nothing there. Mainstream scientists have already looked into the EmDrive years ago and convinced themselves it doesn't work.
Do you have any details of mainstream scientists looking into it? I've been following the EmDrive some years and can't find any evidence of this -- not even the results of Boeing's tests on it in 2009. (Rumoured to be positive, but only a rumour)
The only mainstream science I've seen on it is the work by Jan Yuan and co, and that all seems to be positive. Mainstream scientists have certainly dimissed it, but I don't know if they've looked at it. -
#598 by Rodal on 15 Sep, 2014 19:24
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Here is an article with a more accepting slant. Still has errors but what can you do. The tests were NOT performed in vacuum.
http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive
I have been trying to find out whether some of the tests were preformed in a vacuum. From the paper, it sounds as though some of them were not -- but why have the detailed description of the evacuation process if none of them were? Can anyone shed any light?
Also, my understanding is that this technology could fit on a cubesat, presumably that would be a fairly cheap test?
Hi,
The Wired UK article was very confusing to me when I first saw it weeks ago. The Wired UK staff should have done a better job. It gives the impression that some of the NASA "Anomalous thrust ..." experiments were conducted inside a vacuum chamber in a partial vacuum:
<<the full report describes tests in which turbo vacuum pumps were used to evacuate the test chamber to a pressure of five millionths of a Torr, or about a hundred-millionth of normal atmospheric pressure.>> WRONG !
These particular tests (the reported NASA Cannae and Frustum tests) were NOT conducted in a vacuum. They were conducted at ambient pressure.
The NASA authors state in the paper that none of these tests (reported in the NASA "Anomalous thrust ..." paper ) were conducted in a vacuum because they realized that the electrolytic capacitors they had would not work in a vacuum.
Dr. Woodward conducted some of his tests in a vacuum (NOT at a NASA facility).
_______________________________
<<Also, my understanding is that this technology could fit on a cubesat, presumably that would be a fairly cheap test?>>
It would cost several millions of dollars at a minimum (not cheap for me but cheaper than it would have cost decades ago). Also, whether these devices are ready for scale-up and testing in space is a debatable subject that is being debated in this thread...
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#599 by JPLeRouzic on 15 Sep, 2014 20:29
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A) There is a claim that there can be rocket propulsion produced without on-board propellant and without an outside force propelling it (i.e. solar propulsion, electrodynamic tethers, etc.)
That's not extraordinary, as you mention an electric tether does this. Are you sure there is nothing similar at work in EMDrive and others? There are many perfectly classical explanations for those experiments.
What is interesting is when an experimentation is reproducible and I don't see this here.
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