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#440 by Bob012345 on 28 Jun, 2017 19:16
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Project Orion got to a high level of conceptual development and did flight testing with conventional explosives, so yeah, I think it would have flown. Besides all that, there is nothing in our current understanding of physics that forbids it's operation.
Once someone provides solid, demonstrable evidence that you can use these drives to move objects, then you will find a lot more effort put into finding out how it works.
WRT understanding of physics - very true. The theoretical basis of EMDrive should continue to be explored and discussed!!!! A firm basis and understanding of EMDrive (assuming it exists) will shorten any development efforts enormously. The discussions here are fantastic and wonderful. I feel good if I manage to understand at least 50% of them but they are stretching my journeyman math skills and knocking the rust of some of my 40 year old semi-skills such as tensors.
Orion's challenges lay more in the realm of engineering physics such flight dynamics, control and shock/jolt management; not to mention reliable fuel (bomblet) feed and ignition. On one of my first assignments as a junior engineer out of college the project engineer had been a very junior engineer on Orion. As I had done my senior thesis on updating some of the challenges of Orion and their possible solution he and I had some interesting discussions. BTW here is a pretty good video of the flight tests (done in 1950's newsreel fashion)
Why am I harping on Project Orion in the EMDrive forum. Because I think there are some project development concepts that can be useful. Not the design, but the approach to solving problems and testing. While the basic physics of Orion was understood of course, Orion had some significant physics issues - Freeman Dyson was borrowed from the Institute for Advanced Studies to work with General Atomics on Orion. Orion was a serious effort to develop interplanetary capability (among others) before we had even reached the moon.
The concept of developing the free flyer using dynamite is an example of the kind of exploratory approach I am thinking would benefit the EMDrive efforts. They used simple designs to explore unknown behaviors of specific issues. No - I am not suggesting dynamite bombs under a frustum BUT perhaps some more detailed exploration of frustum shape, materials and RF feed/resonance would be of benefit i.e. not trying to measure (notional) thrust but exploring open issues i.e. shape, end cap design, aspect ratio, mode stimulation and control, resonance establishment and control. effect of dielectrics (type, locations etc) - just some examples, by no means a complete list. BTW - some or most of these are well within the technical capability of DIYers. Yes - my money is where my mouth is - I am working up a test plan and lab right now.
Reading the history of Orion and other similar efforts provides a good brainstorming start for areas to explore in the EMDrive pantheon.
Herman
graybeardsyseng
Yes, please design for big effects and not micronewtons! -
#441 by X_RaY on 28 Jun, 2017 20:05
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Even a definitive final confirmation/verification within the micronewton regime would be a revolution!Project Orion got to a high level of conceptual development and did flight testing with conventional explosives, so yeah, I think it would have flown. Besides all that, there is nothing in our current understanding of physics that forbids it's operation.
Once someone provides solid, demonstrable evidence that you can use these drives to move objects, then you will find a lot more effort put into finding out how it works.
WRT understanding of physics - very true. The theoretical basis of EMDrive should continue to be explored and discussed!!!! A firm basis and understanding of EMDrive (assuming it exists) will shorten any development efforts enormously. The discussions here are fantastic and wonderful. I feel good if I manage to understand at least 50% of them but they are stretching my journeyman math skills and knocking the rust of some of my 40 year old semi-skills such as tensors.
Orion's challenges lay more in the realm of engineering physics such flight dynamics, control and shock/jolt management; not to mention reliable fuel (bomblet) feed and ignition. On one of my first assignments as a junior engineer out of college the project engineer had been a very junior engineer on Orion. As I had done my senior thesis on updating some of the challenges of Orion and their possible solution he and I had some interesting discussions. BTW here is a pretty good video of the flight tests (done in 1950's newsreel fashion)
Why am I harping on Project Orion in the EMDrive forum. Because I think there are some project development concepts that can be useful. Not the design, but the approach to solving problems and testing. While the basic physics of Orion was understood of course, Orion had some significant physics issues - Freeman Dyson was borrowed from the Institute for Advanced Studies to work with General Atomics on Orion. Orion was a serious effort to develop interplanetary capability (among others) before we had even reached the moon.
The concept of developing the free flyer using dynamite is an example of the kind of exploratory approach I am thinking would benefit the EMDrive efforts. They used simple designs to explore unknown behaviors of specific issues. No - I am not suggesting dynamite bombs under a frustum BUT perhaps some more detailed exploration of frustum shape, materials and RF feed/resonance would be of benefit i.e. not trying to measure (notional) thrust but exploring open issues i.e. shape, end cap design, aspect ratio, mode stimulation and control, resonance establishment and control. effect of dielectrics (type, locations etc) - just some examples, by no means a complete list. BTW - some or most of these are well within the technical capability of DIYers. Yes - my money is where my mouth is - I am working up a test plan and lab right now.
Reading the history of Orion and other similar efforts provides a good brainstorming start for areas to explore in the EMDrive pantheon.
Herman
graybeardsyseng
Yes, please design for big effects and not micronewtons!
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#442 by dustinthewind on 29 Jun, 2017 01:17
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I was just reading and noticed meberbs had figured out the 2nd order doppler effects which I thought was cool here: https://forum.nasaspaceflight.com/index.php?topic=37642.msg1413761#msg1413761 when a thought struck me.
Light is able to transfer more of its energy effectively to a lighter object such as a free electron than it is able to transfer its energy to a more massive object. Now in the tip of the frustum we have some large electric fields which could possibly ionize gas while at the large end ionization may be less so.
So lets say we have this ion cloud at the tip of the frustum and the photons are impacting free electrons up there and more effectively transferring energy. After the electron "more effectively" absorbs some momentum this transfers some to the proton/nucleus afterwards and these air particles effectively then strike the cavity. The cavity more effectively gains momentum because the air particles are much more massive than photons. The air particles having lost some of their momentum return with less velocity only to repeat the process. So we have momentum more effectively being absorbed from photons at the narrow end of the cavity than from the big end.
Light striking the large end after the drive accelerates is less able to absorb its momentum back (via the 2nd order effects of a Doppler shift), so over all light loses energy.
Could that possibly make sense?
What is curious about a plasma possibly existing in the cavity is that the plasma can more effectively absorb kinetic energy from light. I think I remember Shell mentioning the possibility of plasma in the cavity at one point in time. Possibly this is why she made her cavity see through or that screen mesh? The plasma would need to be created, so energy would start to be stored in the cavity and later plasma could form when the electric fields become strong enough to strip electrons from the gasses inside.
The formation of too much plasma and I question if it could possibly start to interfere with the stored energy in the cavity,(the free electrons being too reflective), the wavelength might not constructively interfere any more, causing energy to be rejected from the cavity. For it to work, some light would have to pass through the plasma and resonate in the cavity to sustain the electric fields that sustain the plasma.
After that you need light that resonates between the big cavity wall and the plasma toward the narrow end of the cavity. The plasma doesn't need to touch the cavity wall and should in fact be repelled from the changing magnetic field via the currents in the cavity. So basically the plasma more effectively absorbs kinetic energy from light and then passes this on to the cavity via repulsion off the cavities changing magnetic field.
The need to sustain both currents in the cavity at a certain wavelength, and current induced in the plasma via another wavelength may mean multiple wavelengths are required.
This provides a possible means for the cavity to travel pointed end forwards if the plasma is near the pointed end but may depend on the plasma's location and possibly/possibly not with respect to where your injecting the radiation. I.e. I'm not sure what effect it would have to inject the radiation inside the plasma as opposed to injecting the radiation at the end where there is no plasma. I suspect injecting radiation in the middle of the plasma may have an effect of reducing any propulsive effect but maybe not.
I would suspect you would want the location of the injecting antenna to be about a quarter wavelength away from the big plate for both injected wavelengths. Could this be why large freq. splatter of microwave oven magnetrons work? (injecting multiple wavelengths?)
Does it coinside with experimental evidence suggesting some minimal power level required for the effect to really take hold. Some minimal power required to form plasma? -
#443 by aero on 29 Jun, 2017 01:28
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Quote
Even a definitive final confirmation/verification within the micronewton regime would be a revolution!
But according to Meep, we can get an order of magnitude over a photon rocket just by radiating evanescent waves through gaps in the big end. Of course, Meep results may be suspect and my operation of Meep is justifiably suspect.
I did this work back in 2015 and posted some of it. That was just after I had started using Meep and knew nothing about it. I quit pursuing this approach because the results were all over the place so I thought then, and maybe still think, that there were problems in my understanding of the tool I was using. Many of the runs showed much more force than the attached but ... Well, if these runs were right after all, then maybe some of the other runs showing micro-newton forces were also realistic?
Steve
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#444 by Monomorphic on 29 Jun, 2017 12:40
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Does it coincide with experimental evidence suggesting some minimal power level required for the effect to really take hold. Some minimal power required to form plasma?
Based on this image from Shawyer's recent television appearance, I was able to locate the amplifier shown below. That amplifier is 50W max: https://tinyurl.com/y9g3mxol
At 50W there will be E-fields at ~200 kV/m inside the cavity according to FEKO simulations. Electrical breakdown of air begins at about 3,000kV/m.
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#445 by Star One on 29 Jun, 2017 12:56
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Hi guys,
Just found out following information about the EmDrive development.
BBC made a report about the Gilo Industries on 4.4. 2017 that I missed (shame on me!). They spoke a bit about that new investment from the Kuang-Chi this year.
Mr. Gilo also mentions something interesting. That "they can not yet speak about the best thing they made" and that they may reveal it later this year.
Of course it can be anything. They work on many interesting project, but given the fact, that we know about their cooperation with Mr. Shawyer there is some probability it can be the EmDrive.
This supports, that Mr. Shawyer mentions in his presentation work on "new superconducting cavity desing" with Gilo Industries (2015).
Here is the link and the attachment:
https://goo.gl/ixUF72
Could you expand on this report by the BBC by providing further details of what program it was on, was it on TV or radio, was it in a documentary or part of the news? -
#446 by mk65 on 29 Jun, 2017 14:19
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#447 by SeeShells on 29 Jun, 2017 15:03
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Does it coincide with experimental evidence suggesting some minimal power level required for the effect to really take hold. Some minimal power required to form plasma?
Based on this image from Shawyer's recent television appearance, I was able to locate the amplifier shown below. That amplifier is 50W max: https://tinyurl.com/y9g3mxol
At 50W there will be E-fields at ~200 kV/m inside the cavity according to FEKO simulations. Electrical breakdown of air begins at about 3,000kV/m.
Monomorphic,
Let's look at this in another way, by developing a ionization or coronal discharges.
Tipler, Paul A. College Physics. Worth, 1987: 467Quote"This phenomenon, which is called dielectric breakdown, occurs in air at an electric field strength of about Emax = 3 × 106 V/m." 3 × 106 V/m"
That works out roughly to .3KV/M dependent of several factors within the frustum to start the process creating an ionization of the air.
That's not what I was looking at.
https://en.wikipedia.org/wiki/Corona_discharge
https://en.wikipedia.org/wiki/Peek%27s_law
The values for the last two parameters are usually considered to be about 30-32 kV/cm (in air [1]) and 0.301 cm½ respectively. This latter law can be considered to hold also in different setups, where the corresponding voltage is different due to geometric reasons.
Shell
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#448 by graybeardsyseng on 29 Jun, 2017 15:10
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Even a definitive final confirmation/verification within the micronewton regime would be a revolution!
Indeed - as an old saying goes (likely I am misquoting and I can't remember the source so my apologies in advance to the originator) - "The distance between 0 and 1 is far greater than the distance between 1 and 100." Final Definitive confirmation will be a paradigm shift about 9.0 on the Richter scale (to mix and mangle some metaphors). Although I do suspect that (if) and when even micronewton thrust is confirmed substantial improvements will be possible between establishing a theoretical underpinning and conducing a thorough set of engineering performance testing against a wide range of parameters.
Herman
graybeardsyseng
Edited to fix quote command syntax error -
#449 by Monomorphic on 29 Jun, 2017 16:09
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Quote
"This phenomenon, which is called dielectric breakdown, occurs in air at an electric field strength of about Emax = 3 × 106 V/m." 3 × 106 V/m"
That works out roughly to .3KV/M dependent of several factors within the frustum to start the process creating an ionization of the air.
Wolfram says it's 3000 kV/m: https://www.wolframalpha.com/input/?i=3+%C3%97+10%5E6+V%2Fm+to+kV%2Fm
30 kv/cm is 3,000 kV/m
To get to 3000kV/m lobes just on the small end, FEKO results are ~15kW.
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#450 by Monomorphic on 29 Jun, 2017 17:43
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Hold on, I used kV/m when it should be kV/cm. Let me redo that. Will edit the comment above.
30 kV/cm is 3000 kV/m. https://www.wolframalpha.com/input/?i=30+kV%2Fcm+to+kV%2Fm
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#451 by SeeShells on 29 Jun, 2017 17:48
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Hold on, I used kV/m when it should be kV/cm. Let me redo that.
https://en.wikipedia.org/wiki/Peek%27s_law
30 kV/cm is 3000 kV/m.
The values for the last two parameters are usually considered to be about 30-32 kV/cm (in air [1]) and 0.301 cm½ respectively. This latter law can be considered to hold also in different setups, where the corresponding voltage is different due to geometric reasons.
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#452 by Star One on 29 Jun, 2017 17:56
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I think it might be that one:
http://www.bbc.com/news/av/uk-england-dorset-39478360/dorset-flying-car-firm-to-double-workforce-after-chinese-investment
Thank you. Shame it's so short a report.
Is that Mr Shawyer speaking very briefly towards the end of it? -
#453 by tchernik on 29 Jun, 2017 18:04
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I think it might be that one:
http://www.bbc.com/news/av/uk-england-dorset-39478360/dorset-flying-car-firm-to-double-workforce-after-chinese-investment
Thank you. Shame it's so short a report.
Is that Mr Shawyer speaking very briefly towards the end of it?
Not sure. Intriguing bit, I only got that they "can't talk publicly about it at the moment". -
#454 by dustinthewind on 29 Jun, 2017 18:23
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Thank you Shell and Mono. I take it that means it is not likely there is ionized air at the top of the cavity, trapped in that standing electric field. On the other hand... What about resonance
with moisture? Microwaves do resonate with water. I wonder if they took that into account. I am guessing the 3000kv/m is a non-resonant figure.sorry microwaves do not resonate water molecules. -
#455 by Star One on 29 Jun, 2017 18:32
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I think it might be that one:
http://www.bbc.com/news/av/uk-england-dorset-39478360/dorset-flying-car-firm-to-double-workforce-after-chinese-investment
Thank you. Shame it's so short a report.
Is that Mr Shawyer speaking very briefly towards the end of it?
Not sure. Intriguing bit, I only got that they "can't talk publicly about it at the moment".
It sounds to me like a very obvious edit down from a longer sentence? -
#456 by SeeShells on 29 Jun, 2017 18:51
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Thank you Shell and Mono. I take it that means it is not likely there is ionized air at the top of the cavity, trapped in that standing electric field. On the other hand... What about resonance with moisture?
Could be ionization, with my current setup I could ramp to a peak of 2Kw into the frustum.
I don't.
Shell -
#457 by LowerAtmosphere on 29 Jun, 2017 19:57
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Does it coincide with experimental evidence suggesting some minimal power level required for the effect to really take hold. Some minimal power required to form plasma?
Based on this image from Shawyer's recent television appearance, I was able to locate the amplifier shown below. That amplifier is 50W max: https://tinyurl.com/y9g3mxol
At 50W there will be E-fields at ~200 kV/m inside the cavity according to FEKO simulations. Electrical breakdown of air begins at about 3,000kV/m.
Poor cavity design then. Easily solvable, and I believe according to some simulations this limit is passed by an order of magnitude. -
#458 by Monomorphic on 29 Jun, 2017 22:50
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Does it coincide with experimental evidence suggesting some minimal power level required for the effect to really take hold. Some minimal power required to form plasma?
Based on this image from Shawyer's recent television appearance, I was able to locate the amplifier shown below. That amplifier is 50W max: https://tinyurl.com/y9g3mxol
At 50W there will be E-fields at ~200 kV/m inside the cavity according to FEKO simulations. Electrical breakdown of air begins at about 3,000kV/m.
Poor cavity design then. Easily solvable, and I believe according to some simulations this limit is passed by an order of magnitude.
I think I know which simulations you are referring to as I probably did a few of them. The ones with huge e-field strength, like the image below, were performed with a perfect electric conductor as the wall material instead of copper. This is sort of like a superconductor, except none of the exotic superconducting properties are simulated. So the top image below is with a perfect electrical conductor, and the bottom with copper.
When one first starts out simulating cavities, often the default is a perfect electrical conductor. Copper has to be assigned. Using a perfect electrical conductor will inflate the e-fields dramatically.
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#459 by dustinthewind on 30 Jun, 2017 02:55
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While water may not resonate at microwave frequencies it may still be possible to break down air at microwave frequencies. I was reading through this and thought some of you might find this interesting. https://scholar.google.com/scholar?cluster=9798362981310723067&hl=en&as_sdt=0,26Quote
7. Experimental Results
The breakdown experiment consists of filling the cavity with gas
at a certain pressure, increasing the magnetron power while watching the
transmission crystal current until this current reaches a maximum value and
drops suddenly to a lower value. This drop indicates that the gas has
broken down, and the maximum crystal current indicates the breakdown field.
This operation is repeated for a variety of experimental conditions.
