Quote from: Star One on 05/03/2015 07:36 pmJust a general comment even by the low standards of space & science reporting online it seems this particular article has suffered terribly in its wider reporting and analysis. I hope this hasn't caused any damage to the site's reputation.It is not so much the "low standards" but the uncontained urge for sensational reporting that usually does more damage then good.News reporting feels compelled to scale down information to its lowest understandable form, omitting all nuances and subtleties, hence stripping it from its real content and meaning. That's how the casual "mentioning of an observation of an anomaly reported by a NASA engineer" turns into "NASA discovers Startrek-type warpdrive" in no time...Sadly, this does way more harm then good, because it tends to discredit any research attached to the subject.In the same category, you have those who insist in turning the EMdrive into an over-unity device. It really doesn't help for the credibility of the EMdrive. Just stay away from any of those "contaminated" topics and focus on the device, on the theoretical and practical issues of the device...The upcoming high power test, scheduled for July (according P.March), will be the make or brake event for me as I'm still on the balance. I remain skeptical, yet I do carry the hope it turns out to be a positive test, simply because it would mean a giant leap forward for human space exploration (stationary orbital spacestations, human interplanetary travel and even interstellar probe travel).. we'll see... give it another 2-3 months......
Just a general comment even by the low standards of space & science reporting online it seems this particular article has suffered terribly in its wider reporting and analysis. I hope this hasn't caused any damage to the site's reputation.
It is known to be impossible to violate energy conservation. Stating that it clearly does is a non-sequitur, as it implies complete knowledge of how Emdrive works (if it really does work). There is no accepted theory of operation for this thing. For all we know, the universe might be a ginormous energy bank that you can borrow from and loan to; if you know how. You still have to balance the books at the end of the day. (pure conjecture)I think we need to remember that until proven otherwise, this copper can is a black box. It is what it is, regardless of what some guy's theory says about it, which is likely wrong until proven correct.
Quote from: JPHar on 05/03/2015 09:22 pmThis may sound off the wall, but I have an idea for low cost experiments. Use a Crooke's Radiometer positioned adjacent to the device in the thrust direction. Distance to the device, pane charge, temperature, pressure, polarization of light allowed through the radiometer wall, and mill pane materials are controls to be varied. Very low mass panes should be constructed, perhaps by coating thin slivers of aerogel through vacuum metalization or other very thin layer material application processes for the emissive and aborbant sides of the pane. Hypothesis: If any propellant is present, to include virtual particles temporarily conferred enough energy to bring them into a non-virtual state, then it should be possible to observe radiometer motion under the right combination of conditions and materials. The conditions and materials that achieve radiometer motion then provide insight into the nature of propellant.I do not have the expertise to evaluate which materials and conditions should be tried, nor in which order. Skepticism: The mass and friction of the radiometer system must be low enough that a fraction of the thrust generated by the device is sufficient to cause rotation. Experiments using materials with thermoelectric properties or other sophisticated materials may be required and may not be inexpensive. edit: To clarify, the goal in the experiments would not necessarily be to demonstrate thermal phenomena, but to adapt the operating principle of the radiometer to different interactions with the environment until the correct interaction is discovered.You do know how a Crooke's device works don't you? Why would this elucidate anything to do with an EM drive?Maybe I am missing something though...
This may sound off the wall, but I have an idea for low cost experiments. Use a Crooke's Radiometer positioned adjacent to the device in the thrust direction. Distance to the device, pane charge, temperature, pressure, polarization of light allowed through the radiometer wall, and mill pane materials are controls to be varied. Very low mass panes should be constructed, perhaps by coating thin slivers of aerogel through vacuum metalization or other very thin layer material application processes for the emissive and aborbant sides of the pane. Hypothesis: If any propellant is present, to include virtual particles temporarily conferred enough energy to bring them into a non-virtual state, then it should be possible to observe radiometer motion under the right combination of conditions and materials. The conditions and materials that achieve radiometer motion then provide insight into the nature of propellant.I do not have the expertise to evaluate which materials and conditions should be tried, nor in which order. Skepticism: The mass and friction of the radiometer system must be low enough that a fraction of the thrust generated by the device is sufficient to cause rotation. Experiments using materials with thermoelectric properties or other sophisticated materials may be required and may not be inexpensive. edit: To clarify, the goal in the experiments would not necessarily be to demonstrate thermal phenomena, but to adapt the operating principle of the radiometer to different interactions with the environment until the correct interaction is discovered.
Quote from: flux_capacitor on 05/01/2015 08:30 pm...Those people do not know the struggling of a scientist to get just a little more funding in their lab where only 3 or 4 other colleagues work with them. Eagleworks has an old dying RF amp and they do not even have the bucks to replace it… Paul had to build the copper frustum at home, in his wife's dining room! Really people would be shocked if they knew that....Yes, the more crude the instrumentation, the stronger the effect.
...Those people do not know the struggling of a scientist to get just a little more funding in their lab where only 3 or 4 other colleagues work with them. Eagleworks has an old dying RF amp and they do not even have the bucks to replace it… Paul had to build the copper frustum at home, in his wife's dining room! Really people would be shocked if they knew that....
Even if it does work there's a vast gap between that & going on holiday to the moon on a regular four hour shuttle flight. It seems as if people expect to be flying around the Solar System by next year.
But a Crooke's device will rotate even in a uniform radiation field, even your fancy variant.I am not clear how it could be used to test an EM drive, which doesn't emit any photons in a preferred direction.
"It doesn't emit EM radiation that has been detected so far. " The resonator in the NASA reports clearly emits EM radiation in the infrared band, and in an asymmetrical manner. IR radiation produces a recoil force and is now believed to be responsible for the anomalous acceleration of the Pioneer probes.
Before we gets lots of questions about terrestrial applications.Quote18.Q. How can the EmDrive produce enough thrust for terrestrial applications?A. The second generation engines will be capable of producing a specific thrust of 30kN/kW. Thus for 1 kilowatt (typical of the power in a microwave oven) a static thrust of 3 tonnes can be obtained, which is enough to support a large car. This is clearly adequate for terrestrial transport applications.The static thrust/power ratio is calculated assuming a superconducting EmDrive with a Q of 5 x 109. This Q value is routinely achieved in superconducting cavities.Note however, because the EmDrive obeys the law of conservation of energy, this thrust/power ratio rapidly decreases if the EmDrive is used to accelerate the vehicle along the thrust vector. (See Equation 16 of the theory paper). Whilst the EmDrive can provide lift to counter gravity, (and is therefore not losing kinetic energy), auxiliary propulsion is required to provide the kinetic energy to accelerate the vehicle.http://emdrive.com/faq.html
18.Q. How can the EmDrive produce enough thrust for terrestrial applications?A. The second generation engines will be capable of producing a specific thrust of 30kN/kW. Thus for 1 kilowatt (typical of the power in a microwave oven) a static thrust of 3 tonnes can be obtained, which is enough to support a large car. This is clearly adequate for terrestrial transport applications.The static thrust/power ratio is calculated assuming a superconducting EmDrive with a Q of 5 x 109. This Q value is routinely achieved in superconducting cavities.Note however, because the EmDrive obeys the law of conservation of energy, this thrust/power ratio rapidly decreases if the EmDrive is used to accelerate the vehicle along the thrust vector. (See Equation 16 of the theory paper). Whilst the EmDrive can provide lift to counter gravity, (and is therefore not losing kinetic energy), auxiliary propulsion is required to provide the kinetic energy to accelerate the vehicle.
Question from a layman... if the EM Drive works as described, would there be a force against whatever is behind it?For example, a helicopter causes a lot of wind beneath the blades and displaces dust. Would an EM Drive do the same?
Quote from: Star One on 04/29/2015 07:32 pmBefore we gets lots of questions about terrestrial applications.Quote18.Q. How can the EmDrive produce enough thrust for terrestrial applications?A. The second generation engines will be capable of producing a specific thrust of 30kN/kW. Thus for 1 kilowatt (typical of the power in a microwave oven) a static thrust of 3 tonnes can be obtained, which is enough to support a large car. This is clearly adequate for terrestrial transport applications.The static thrust/power ratio is calculated assuming a superconducting EmDrive with a Q of 5 x 109. This Q value is routinely achieved in superconducting cavities.Note however, because the EmDrive obeys the law of conservation of energy, this thrust/power ratio rapidly decreases if the EmDrive is used to accelerate the vehicle along the thrust vector. (See Equation 16 of the theory paper). Whilst the EmDrive can provide lift to counter gravity, (and is therefore not losing kinetic energy), auxiliary propulsion is required to provide the kinetic energy to accelerate the vehicle.http://emdrive.com/faq.htmlMaybe this is a stupid question, but if thrust drops off rapidly when used to accelerate the vehicle along the thrust vector, how can it be useful for interstellar travel? You would be wanting to accelerate the vehicle in the same direction of the thrust for a long period of time (toward the target star system). I can only imagine that it would be useful for lifting payloads to a certain altitude, or repositioning from LEO to GEO. Watching the Shawyer Youtube videos, he even says that a propellant is needed to get up to orbital velocity once the altitude is achieved.
Maybe this is a stupid question, but if thrust drops off rapidly when used to accelerate the vehicle along the thrust vector, how can it be useful for interstellar travel? You would be wanting to accelerate the vehicle in the same direction of the thrust for a long period of time (toward the target star system). I can only imagine that it would be useful for lifting payloads to a certain altitude, or repositioning from LEO to GEO. Watching the Shawyer Youtube videos, he even says that a propellant is needed to get up to orbital velocity once the altitude is achieved.
Quote from: ragingrei on 05/04/2015 02:16 amQuestion from a layman... if the EM Drive works as described, would there be a force against whatever is behind it?For example, a helicopter causes a lot of wind beneath the blades and displaces dust. Would an EM Drive do the same?That's kind of like asking if a Unicorn existed what it's horn would be made of.There are different proposed theories for what might cause an EM Drive to work, if it did work. Some people think all the proposed theories are likely wrong, even if it does work.This is like people speculating about what the canals of Mars were made from, back during the craze when so many people thought they saw canals at the fringe of detectability through their telescopes.
So this made me think about the time I took a 3 port circulator apart. For those that are not familiar with circulators, the work like this:Put power in port 1 and it comes out port 2, put it in 2 and it comes out 3, put it in 3 and it comes out 1. All with out much loss. But if you try to go backwards, say 3 to 2, you loose 99% of the power. Cool little device. So when I take it apart all it is is a flat triangle of copper, 2 triangle shaped pieces of ferrite, and a magnet.If you don't know the math behind it, is looks at first blush as "silly" as the emdrive. No way could it do that. But it does. This thing may well work, we just don't know the math.
Quote from: LasJayhawk on 05/03/2015 05:43 amSo this made me think about the time I took a 3 port circulator apart. For those that are not familiar with circulators, the work like this:Put power in port 1 and it comes out port 2, put it in 2 and it comes out 3, put it in 3 and it comes out 1. All with out much loss. But if you try to go backwards, say 3 to 2, you loose 99% of the power. Cool little device. So when I take it apart all it is is a flat triangle of copper, 2 triangle shaped pieces of ferrite, and a magnet.If you don't know the math behind it, is looks at first blush as "silly" as the emdrive. No way could it do that. But it does. This thing may well work, we just don't know the math.I'm an Engineer and I've studied the Polarizable Vacuum Model of General Relativity. What it would say is the following;As a waveguide, the group velocity is something like;v_g = c x sqrt(1 - (c/2d*f)^2)Where, c is the usual speed of light, d is the diameter of the cylinder, and f is the frequency of the microwave excitation.c/2d = fc, is the Low cut-off frequency of the waveguide. The refractive index depends on the Low cut-off frequency as a function of the diameter, K = 1/sqrt( 1 - (fc/f)^2)For f >> fc, K~1. But for frequencies in the band fc1 < f <~ fc2, K is much larger.There is a strong gradient in the refractive index from one end of the cone to the other. This "mimics" gravity, as interpreted in the PV Model.Therefore, we can assume there is a "gravitational" gradient in the microwave band refractive index, along the length of the cone. At one end they have diameter d1, and at the other end they have diameter d2, and d1 > d2. Below fc1, the mode frequencies exponentially decay to zero. Just like the Casimir effect.Here is how it conserves momentum;In the PV Model, momentum transforms as,p => p*sqrt(K)In a resonant cavity, p is the SUM of all the photons “in phase", minus the losses of the cavity. However, as photons “fall” from the large end toward the small end, they gain momentum, which is passed on to the cone when they are reflected from the small end. The photon then loses momentum as it travels back to the large end, where it imparts “less” momentum to the large end. The result is a NET propulsion in the direction of the small end. In other words, the photons are blue-shifted falling forward, and red-shifted going backwards, due to the gradient in the refractive index. It is literally gravitational red & blue shift, according to the PV Model.The interesting thing is, the refractive index in the waveguide does not depend on the power of the microwaves, or the energy density. It is simply a matter of the geometry and frequency band relative to the cut-off. What matters more, is having enough resonant momentum stored to make the effect noticeable.That’s IMHO as an engineer of course. Any comments?See PV Model: https://www.researchgate.net/publication/223130116_Advanced_Space_Propulsion_Based_on_Vacuum_%28Spacetime_Metric%29_EngineeringTodd D.