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#3120 by SteveD on 24 Feb, 2016 22:35
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By revolving the frustum and extending along the central axis, I was able to create a helical frustum with curved end-plates. This geometry is ideal for recycling photons without causing interference and seems like a viable way to "stack" emdrives and still only use one RF source. Can't wait to get it into FEKO.
Here is the model in sketchfab so you can orbit and zoom:https://skfb.ly/L97F
Considering the small physical size of your proposed -- optical range -- test article, do you plan to test this shape along with a, conventional, frustum? -
#3121 by jmossman on 24 Feb, 2016 22:56
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(...)
(...)
Here is the model in sketchfab so you can orbit and zoom:https://skfb.ly/L97F
According to my interpretation of Dr. White's QV theory, this torus design should be considerably worse than the frustum of a cone design (when comparing an equivalent frustum of a cone with similar outside dimensions).
The important thing is the Energy Density (for the QV theory and for other theories based on General Relativity, like Minotti's, Trunov, etc.).
For example, this is the Energy Density distribution for mode shape TE013:
This torus shape prevents the Energy Density from achieving its maximum at the inside core of the EM Drive, and instead it substitutes it for a thin ring on the outside periphery.
For a constant InputPower that is optimal for a frustum geometry, I too would expect a torus shape to have a lower Force/InputPower efficiency.
If I recall, Dr. Yang reported a reduction in Force/InputPower as InputPower was increased beyond a certain threshold. If there is an "upper bounds" of Force/InputPower for a frustum, then the torus might provide an interesting way to increase the volume of the cavity while minimizing the cavity wall parasitics (i.e. losses due to resistivity, etc). If the torus can support similar mode shapes to the frustum, then perhaps the torus provides an approach to utilizing higher InputPower while maintaining Force/InputPower efficiency and minimizing the total mass (and parasitic losses) of the system. Perhaps the torus' minimization of mass and parasitic losses would provide a path to improving Force/InputPower efficiency at higher InputPower and constant frequency?
An analogy that comes to mind is that the Force/InputPower from a propeller reaches an upper threshold once it reaches a design RPM (where RevolutionsPerMinute [RPM] approximates kinetic energy as InputPower in my analogy, and glosses over the properties of the fluidic medium, propeller geometry, mass, etc).
Perhaps counting chickens before they hatch....
Back to lurking....
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#3122 by Rodal on 24 Feb, 2016 23:34
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To increase the Force/InputPower and to increase the quality factor Q, the best way is just to increase the size of the frustum of a cone.(...)
(...)
Here is the model in sketchfab so you can orbit and zoom:https://skfb.ly/L97F
According to my interpretation of Dr. White's QV theory, this torus design should be considerably worse than the frustum of a cone design (when comparing an equivalent frustum of a cone with similar outside dimensions).
The important thing is the Energy Density (for the QV theory and for other theories based on General Relativity, like Minotti's, Trunov, etc.).
For example, this is the Energy Density distribution for mode shape TE013:
This torus shape prevents the Energy Density from achieving its maximum at the inside core of the EM Drive, and instead it substitutes it for a thin ring on the outside periphery.
For a constant InputPower that is optimal for a frustum geometry, I too would expect a torus shape to have a lower Force/InputPower efficiency.
If I recall, Dr. Yang reported a reduction in Force/InputPower as InputPower was increased beyond a certain threshold. If there is an "upper bounds" of Force/InputPower for a frustum, then the torus might provide an interesting way to increase the volume of the cavity while minimizing the cavity wall parasitics (i.e. losses due to resistivity, etc). If the torus can support similar mode shapes to the frustum, then perhaps the torus provides an approach to utilizing higher InputPower while maintaining Force/InputPower efficiency and minimizing the total mass (and parasitic losses) of the system. Perhaps the torus' minimization of mass and parasitic losses would provide a path to improving Force/InputPower efficiency at higher InputPower and constant frequency?
An analogy that comes to mind is that the Force/InputPower from a propeller reaches an upper threshold once it reaches a design RPM (where RevolutionsPerMinute [RPM] approximates kinetic energy as InputPower in my analogy, and glosses over the properties of the fluidic medium, propeller geometry, mass, etc).
Perhaps counting chickens before they hatch.... Back to lurking....
This fact is proven, analytically, step by step, in this post: http://forum.nasaspaceflight.com/index.php?topic=39214.msg1474347#msg1474347
Actually I can formally prove the opposite of what you state: the torus shape will have a lower Q quality factor and so will the Helix-shapen cavities.
This follows from the fact that the losses all take place in the metal skin. The torus shape and the helix shape increase the amount of metal surface for a given internal volume.
There is no doubt about the fact that to increase the Q, one wants a (maximum volume)/ (Surface Area) ratio.
To increase the Q, one should do all the opposite: instead of having a big hole in the middle, one wants to decrease the surface area: having a frustum shape that would look more like half of a football perhaps. The worst shape for Q is one that maximizes the amount of surface area: one that introduces internal surfaces for more power to get dissipated and hence lower the Q.
The following shapes, for similar outside dimensions, will have a significantly lower Q and they will also run into the Yang limitation sooner since the field densities will reach a limit earlier:
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#3123 by rfmwguy on 24 Feb, 2016 23:37
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Been reading a lot of ideas and theories in T1-T6 and would like to pose a question for discussion or future consideration.
Assuming the emdrive is an open system and continues to demonstrate observational results, it may be well beyond the capabilites of any research laboratory to directly measure whatever it might be interacting with outside its confines.
Just wanted to posit this in the minds of some of the theoretical braintrusts here. Not being a theoretical type, not sure where indirect measurements fit into the big scheme of things regarding acceptance in the scientific community. -
#3124 by Monomorphic on 24 Feb, 2016 23:42
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Considering the small physical size of your proposed -- optical range -- test article, do you plan to test this shape along with a, conventional, frustum?
I will test a conventional frustum (with concave/convex end plates) first. If there is any reaction, then I will double the input power. If progress is made, then I may consider these more exotic geometries to further increase efficiency. I expect the torus and helix to be much more difficult to fabricate than the conventional frustum, with the helix being the most difficult. -
#3125 by Rodal on 24 Feb, 2016 23:44
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Been reading a lot of ideas and theories in T1-T6 and would like to pose a question for discussion or future consideration.
Assuming the emdrive is an open system and continues to demonstrate observational results, it may be well beyond the capabilites of any research laboratory to directly measure whatever it might be interacting with outside its confines.
Just wanted to posit this in the minds of some of the theoritical braintrusts here. Not being a theoretical type, not sure where indirect measurements fit into the big scheme of things regarding acceptance in the scientific community.
Not beyond the limits of laboratories at CERN, Fermilab, etc., or beyond the capabilities of MIT Research staff, if they would be interested in pursuing it (they have more interesting things to work on at the moment). -
#3126 by rfmwguy on 24 Feb, 2016 23:55
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That's good news doc. Anything that is out of reach right now? Dark matter/energy come to mind, can't think of any theoretical particles or unknown fields left to measure directly...of course I've left out our friend deltamass' floobie dustBeen reading a lot of ideas and theories in T1-T6 and would like to pose a question for discussion or future consideration.
Assuming the emdrive is an open system and continues to demonstrate observational results, it may be well beyond the capabilites of any research laboratory to directly measure whatever it might be interacting with outside its confines.
Just wanted to posit this in the minds of some of the theoritical braintrusts here. Not being a theoretical type, not sure where indirect measurements fit into the big scheme of things regarding acceptance in the scientific community.
Not beyond the limits of laboratories at CERN, Fermilab, etc., or beyond the capabilities of MIT Research staff, if they are interested.
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#3127 by SeeShells on 25 Feb, 2016 00:02
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To increase the Force/InputPower and to increase the quality factor Q, the best way is just to increase the size of the frustum of a cone.(...)
(...)
Here is the model in sketchfab so you can orbit and zoom:https://skfb.ly/L97F
According to my interpretation of Dr. White's QV theory, this torus design should be considerably worse than the frustum of a cone design (when comparing an equivalent frustum of a cone with similar outside dimensions).
The important thing is the Energy Density (for the QV theory and for other theories based on General Relativity, like Minotti's, Trunov, etc.).
For example, this is the Energy Density distribution for mode shape TE013:
This torus shape prevents the Energy Density from achieving its maximum at the inside core of the EM Drive, and instead it substitutes it for a thin ring on the outside periphery.
For a constant InputPower that is optimal for a frustum geometry, I too would expect a torus shape to have a lower Force/InputPower efficiency.
If I recall, Dr. Yang reported a reduction in Force/InputPower as InputPower was increased beyond a certain threshold. If there is an "upper bounds" of Force/InputPower for a frustum, then the torus might provide an interesting way to increase the volume of the cavity while minimizing the cavity wall parasitics (i.e. losses due to resistivity, etc). If the torus can support similar mode shapes to the frustum, then perhaps the torus provides an approach to utilizing higher InputPower while maintaining Force/InputPower efficiency and minimizing the total mass (and parasitic losses) of the system. Perhaps the torus' minimization of mass and parasitic losses would provide a path to improving Force/InputPower efficiency at higher InputPower and constant frequency?
An analogy that comes to mind is that the Force/InputPower from a propeller reaches an upper threshold once it reaches a design RPM (where RevolutionsPerMinute [RPM] approximates kinetic energy as InputPower in my analogy, and glosses over the properties of the fluidic medium, propeller geometry, mass, etc).
Perhaps counting chickens before they hatch.... Back to lurking....
This fact is proven, analytically, step by step, in this post: http://forum.nasaspaceflight.com/index.php?topic=39214.msg1474347#msg1474347
Actually I can formally prove the opposite of what you state: the torus shape will have a lower Q quality factor and so will the Helix-shapen cavities.
This follows from the fact that the losses all take place in the metal skin. The torus shape and the helix shape increase the amount of metal surface for a given internal volume.
There is no doubt about the fact that to increase the Q, one wants a (maximum volume)/ (Surface Area) ratio.
To increase the Q, one should do all the opposite: instead of having a big hole in the middle, one wants to decrease the surface area: having a frustum shape that would look more like half of a football perhaps. The worst shape for Q is one that maximizes the amount of surface area: one that introduces internal surfaces for more power to get dissipated and hence lower the Q.
The following shapes, for similar outside dimensions, will have a significantly lower Q and they will also run into the Yang limitation sooner since the field densities will reach a limit earlier:
I think this was one of the most telling and insightful posts you've done Dr. Rodal. It was copied, pasted and printed out to add into my engineering notebook. Well done.
Sorry, I'm so quiet, but I've just got lots to get done and things happened this week to make it busier. I'm not complaining at all.
So I've some fliers, pdf papers, quotes and numbers to crunch before today gets over with.
Shell
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#3128 by Rodal on 25 Feb, 2016 00:02
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I am basing my above statement on the really small amounts of power (2 watts to 1 kW) that have been used to conduct EM Drive experiments. Compare that with the amount of power at which experiments can be run at CERN, Fermilab or at MIT, and why it takes large amounts of energy to find things that are difficult to find. (Of course, using astrophysical observatories, one can observe at events in the Cosmos that naturally release huge amounts of energy, so astrophysical observations is one of the most fertile ways to discover "new physics").
That's good news doc. Anything that is out of reach right now? Dark matter/energy come to mind, can't think of any theoretical particles or unknown fields left to measure directly...of course I've left out our friend deltamass' floobie dustBeen reading a lot of ideas and theories in T1-T6 and would like to pose a question for discussion or future consideration.
Assuming the emdrive is an open system and continues to demonstrate observational results, it may be well beyond the capabilites of any research laboratory to directly measure whatever it might be interacting with outside its confines.
Just wanted to posit this in the minds of some of the theoritical braintrusts here. Not being a theoretical type, not sure where indirect measurements fit into the big scheme of things regarding acceptance in the scientific community.
Not beyond the limits of laboratories at CERN, Fermilab, etc., or beyond the capabilities of MIT Research staff, if they are interested. -
#3129 by rfmwguy on 25 Feb, 2016 00:13
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Got it. I'm just uncertain about past, present and future emdrive theories relying on anything that involves something that cannot be measured directly. Some great minds never let this get in their way. Just in a learning mode on formal theory ... I may never develop my own, mind you.
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#3130 by Rodal on 25 Feb, 2016 00:16
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Got it. I'm just uncertain about past, present and future emdrive theories relying on anything that involves something that cannot be measured directly. Some great minds never let this get in their way. Just in a learning mode on formal theory ... I may never develop my own, mind you.
Tell yourself this: measuring something is interacting, coupling with something.
If the EM Drive anomalous force is not an experimental artifact, in essence the EM drive experiments are already measuring that something.
Tell yourself that what you are looking for is another way to "measure that something" (other than measuring the anomalous force).
How about measuring the fields inside the EM Drive?
Not much has been measured up to now: most experiments have not even measured the mode shape.
Shawyer never published a single experiment where he reported measurement of a mode shape.
Ditto for Yang.
Only Paul March at NASA has measured one mode shape: TM212 relying on infrared thermal scanning of the exterior. -
#3131 by rfmwguy on 25 Feb, 2016 00:41
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Heavy endplates will make a good thermal pic more difficult. Did read simple thermal paper internally on a baseplate might work. Other than that, am at a dead end on internal field measurements outside of modeling.Got it. I'm just uncertain about past, present and future emdrive theories relying on anything that involves something that cannot be measured directly. Some great minds never let this get in their way. Just in a learning mode on formal theory ... I may never develop my own, mind you.
Tell yourself this: measuring something is interacting, coupling with something.
If the EM Drive anomalous force is not an experimental artifact, in essence the EM drive experiments are already measuring that something.
Tell yourself that what you are looking for is another way to "measure that something" (other than measuring the anomalous force).
How about measuring the fields inside the EM Drive?
Not much has been measured up to now: most experiments have not even measured the mode shape.
Shawyer is most at fault: he never published a single experiment where he reported measurement of a mode shape.
Ditto for Yang.
Only Paul March at NASA has measured one mode shape: TM212 relying on infrared thermal scanning of the exterior.
One thing I will do with the new frustum is take a lot of near field measurements externally, looking for leaks. The mag injection directly should eliminate many possibilities. Only likely source might be thru filter box on dc supply lines. Plan to check this carefully and modify if needed. -
#3132 by SteveD on 25 Feb, 2016 00:52
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Just a note, it seems like the source a FRB has been located. http://phys.org/news/2016-02-fast-radio-discovery-universe.html
I'm somewhat surprised as I thought these things were likely to be some form of classified terrestrial sat trying to masquerade as an astronomical phenomenon. -
#3133 by SeeShells on 25 Feb, 2016 01:32
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You can image thermal on heavy metal if the heat source remains constant and your willing to do some simple image enhancement.
Heavy endplates will make a good thermal pic more difficult. Did read simple thermal paper internally on a baseplate might work. Other than that, am at a dead end on internal field measurements outside of modeling.Got it. I'm just uncertain about past, present and future emdrive theories relying on anything that involves something that cannot be measured directly. Some great minds never let this get in their way. Just in a learning mode on formal theory ... I may never develop my own, mind you.
Tell yourself this: measuring something is interacting, coupling with something.
If the EM Drive anomalous force is not an experimental artifact, in essence the EM drive experiments are already measuring that something.
Tell yourself that what you are looking for is another way to "measure that something" (other than measuring the anomalous force).
How about measuring the fields inside the EM Drive?
Not much has been measured up to now: most experiments have not even measured the mode shape.
Shawyer is most at fault: he never published a single experiment where he reported measurement of a mode shape.
Ditto for Yang.
Only Paul March at NASA has measured one mode shape: TM212 relying on infrared thermal scanning of the exterior.
One thing I will do with the new frustum is take a lot of near field measurements externally, looking for leaks. The mag injection directly should eliminate many possibilities. Only likely source might be thru filter box on dc supply lines. Plan to check this carefully and modify if needed.
Shell
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#3134 by Rodal on 25 Feb, 2016 13:20
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Dr. Stephen Wolfram ( https://en.wikipedia.org/wiki/Stephen_Wolfram ), famous creator of Wolfram Mathematica and Wolfram Alpha, author of the book A New Kind of Science, spent 6 hours yesterday answering all kinds of questions in the Reddit forum !!!
https://www.reddit.com/r/IAmA/comments/478njk/im_stephen_wolframask_me_anything/
http://blog.stephenwolfram.com/2015/12/what-is-spacetime-really/
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#3135 by rfmwguy on 25 Feb, 2016 13:35
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NASA Funded Advanced Initiatives (NIAC) http://www.nasa.gov/content/funded-studies
Surprised to learn about this initiative at NASA. Videos I've seen commented on $100K grants to private companies/labs as well as people within NASA. Here are a few of the futuristic concepts involving propulsion, there are more.
Head's-up Institutions and Industry:
Seems EMDrive would fit nicely into these approved projects. Note "Propellant-less" and "Ambient Plasma Wave".
Proposal for a Concept Assessment of a Fission Fragment Rocket Engine (FFRE) Propelled Spacecraft
Aneutronic Fusion Spacecraft Architecture
The Fusion Driven Rocket: Nuclear Propulsion through Direct Conversion of Fusion Energy
Pulsed Fission-Fusion (PuFF) Propulsion System
Propellant-less Spacecraft Formation-Flying and Maneuvering with Photonic Laser Thrusters
The Potential for Ambient Plasma Wave Propulsion -
#3136 by rfmwguy on 25 Feb, 2016 13:38
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Dr. Stephen Wolfram ( https://en.wikipedia.org/wiki/Stephen_Wolfram ), famous creator of Wolfram Mathematica and Wolfram Alpha, author of the book A New Kind of Science, spent 6 hours yesterday answering all kinds of questions in the Reddit forum !!!
Anything pertaining to emdrive, Doc?
(snip) -
#3137 by Rodal on 25 Feb, 2016 13:41
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Pertaining to understanding of the spacetime theories discussed by White (NASA), Minotti, Trunov, and others in their discussions of the EM Drive, as discussed in these threads, and pertaining to the computer language (Wolfram Mathematica) and modeling software that was used in previous threads to post-process the Meep simulations for the EM Drive, that provided the only reported stress and Poynting vector field calculations on the EM Drive up to this date in these threads.Dr. Stephen Wolfram ( https://en.wikipedia.org/wiki/Stephen_Wolfram ), famous creator of Wolfram Mathematica and Wolfram Alpha, author of the book A New Kind of Science, spent 6 hours yesterday answering all kinds of questions in the Reddit forum !!!
Anything pertaining to emdrive, Doc?
(snip) -
#3138 by Monomorphic on 25 Feb, 2016 14:26
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I can now get any geometry we want into FEKO. As you can imagine, importing 3d meshes slows down the process considerably, but with some optimization to the geometry (too many unnecessary triangles is bad for performance), i'm getting very reasonable processing times.
Here is a frustum with curved end-plates that is typically-sized. I ran a frequency sweep with 100 steps over about 2 hours and found strong resonance, seen at 2.73737Ghz.
I ran a comparison between a frustum of the same dimensions, except with flat end-plates, and the internal field differences are significant. No resonance at all. Those building flat-end emdrives, and hope to upgrade to curved end-plates eventually, will need to use a different frequency.
Searching for the ideal curved-end frustum shape and size would be perfect for evolutionary algorithms. But since I don't know enough about that to get it up and working, I will just have to brute force it by modeling each generation of frustums and running the sims myself. The goal will be to find the best sized curved and flat end frustums that operate as close to 2.45Ghz as possible (for use with MHT1003NR3).
I'm also working to find the resonant frequency of the helix frustum discussed earlier. Results are promising (I think I have the antenna orientation wrong here though). The mesh has over 600 triangles (it started out over 3,000, but each image took 30 minutes plus) so a full frequency sweep would take many hours. Single images like this still take about 5 minutes each!
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#3139 by Rodal on 25 Feb, 2016 14:51
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I can now get any geometry we want into FEKO. As you can imagine, importing 3d meshes slows down the process considerably, but with some optimization to the geometry (too many unnecessary triangles is bad for performance), i'm getting very reasonable processing times.
How different a frequency for resonance with flat plates vs spherical ends ?
Here is a frustum with curved end-plates that is typically-sized. I ran a frequency sweep with 100 steps over about 2 hours and found strong resonance, seen at 2.72727Ghz.
I ran a comparison between a frustum of the same dimensions, except with flat end-plates, and the internal field differences is significant. No resonance at all. Those building flat-end emdrives, and hope to upgrade to curved end-plates eventually, will need to use a different frequency.
...
For what spherical radii? for what cone half-angles?
One can show that for the geometries of the EM Drive tested up to now (which are very close to cylinders, because the conical angle is small, usually smaller than 20 degrees) that the resonant frequency difference between flat ends and spherical ends should only be a few % in frequency.
For example, for NASA's EM Drive, the difference between the spherical end arc length and the flat end, both in arc length and in height (of the shallow arc) is small, these are very shallow spherical ends. One can also show that the resonant frequency is not that dependent on such small differences.
If your FEKO runs show otherwise, you have to look into the precision and accuracy of the numerical solution, into convergence for different amounts of convexity, as there should not be that much difference in the resonant frequency between flat ends and spherical ends for geometries such as the NASA EM Drive according to the exact solution, and COMSOL FEA runs.
Back to lurking....
