Grenade!http://phys.org/news/2015-03-theorist-gravitational-casimir.html
if experiments show the Casimir pressure to be an order of magnitude larger than that predicted from the photonic contribution alone, this would be the first experimental evidence for the validity of the H-C theory and the existence of gravitons. This would open a new field in the way of graviton detection.
Quote from: aero on 03/04/2015 03:19 amThank you Dr. Rodal - So here is the complete set for some magnetic source run. I didn't record any details except I can see that the antenna in in the location of the magnetic antenna I use. Is it possible that all of the images are correct? If so that would increase my confidence in the meep output.Yes, they can all be correct. But we need your help in identifying the images you posted. The electric and magnetic fields are vectors in 3-D space, with orthogonal base vector components.For example, what does this represent? Is this a contour plot of the electric field component oriented along the axial direction (the vector component oriented along the "y" axis)? The reason why I think it is the axial component is because the axial component should be symmetric about the "y" axis (which it is)Notice how although you impose flat faces, the electromagnetic field inside the cavity wants to be spherical (thus the 2 curved boundaries between the 3 contour regions). Left to its own, Nature will do what it wants to do: to propagate as spherical waves. The radii of the 2 curved boundaries look correct. The radii of curvature seem to have the same center as the focal point of intersection of the sides of the truncated cone (the vertex or apex of the cone).
Thank you Dr. Rodal - So here is the complete set for some magnetic source run. I didn't record any details except I can see that the antenna in in the location of the magnetic antenna I use. Is it possible that all of the images are correct? If so that would increase my confidence in the meep output.
I'm currently trying to finish up the cross section drawing on the flight demonstrator, but i kinda fail to understand how it fits together....Looking closely (top down wise) at the lower rim it seems to me there is :-small shiny rim (could be the edge of the alu cone?)-brownish plate (copper plate?)-small shiny rim-thick plate (most probably holding the screw thread)I'm puzzled about the second small, shiny rim... Why would you need an additional small slab of alu under the (supposedly) copper plating?Any one has an idea?
FYIhttps://www.dropbox.com/s/rtp9gx844yxu6ef/IMAG0372.jpg?dl=0
Quote from: frobnicat on 03/04/2015 01:49 am....The only thing that I see that can account for the apparent lacking torque is the equilibrating torque induced by the inclination of the plane of rotation of the arm toward the CoM of the rotating assembly, that is equivalent to a hanging pendulum. The way it is used, the balance is more than 90% a hanging pendulum and less than 10% a torsion pendulum driven by flexure stiffness.If this analysis holds, small changes in stiffness of flexure bearings would make for a minor impact on results. Changes in inclination would be the major way to tune the (linearised hanging pendulum equivalent) stiffness.A hanging pendulum hangs from a rigid support located above the weight. Its period depends only on the length of the pendulum's arm (and g , the acceleration of gravity, which is practically constant on Earth). The flexural stiffness of the pendulum's arm is negligible.But here nothing is hanging from the stainless steel chamber "rigid ceiling" supported by arms with negligible flexural stiffness.What I see is the EM Drive weight supported by a frame of Faztek aluminum beams, Faztek beams that are supported from below, not from the stainless steel chamber ceiling.What rigid support (located above the EM Drive) is the EM Drive hanging from ? (Where is the "hanging pendulum" rigid support located ?)What constitutes the arm of the "hanging pendulum"? Why does it have negligible flexural stiffness? (The flexural stiffness of the aluminum Faztek beams is far from being negligible)Do you really mean a hanging pendulum (whose period depends only on the length of the arm)? Or do you mean a flexural pendulum (whose period depends on the stiffness of the arm)?And if you agree that the flexural stiffness of the arms are not negligible, why take into account only the portion above the weight? What about the flexural stiffness below the weight? Aren't the Faztek beams supported from below? What I see is your "z" axis going up to a Faztek frame or "bridge" and the "bridge" being supported by two vertical Faztek beams, and those vertical Faztek beams are supported from below, not from above.Is that then really an inverted flexural/torsional pendulum since it is made by Faztek aluminum beams supported from below?... pics ...
....The only thing that I see that can account for the apparent lacking torque is the equilibrating torque induced by the inclination of the plane of rotation of the arm toward the CoM of the rotating assembly, that is equivalent to a hanging pendulum. The way it is used, the balance is more than 90% a hanging pendulum and less than 10% a torsion pendulum driven by flexure stiffness.If this analysis holds, small changes in stiffness of flexure bearings would make for a minor impact on results. Changes in inclination would be the major way to tune the (linearised hanging pendulum equivalent) stiffness.
....It's not about faztek beams compliance. It's about introducing a tilt in the Z axis of rotation (the tilt is around the Y axis) so that the CoM Centre of Mass of the whole rotating assembly, which is not exactly on the Z axis (from the values given by Paul March) but behind the axis (X-) will be lowest when at rest equilibrium position and will have to climb the gravitational potential (ie work against) if it is to deviate from this position (by rotating around the Z axis). ....
The "Copper" is just the reflection of the floor from the side of the flange. The 2 bright lines are reflections from the edge bevels. If they used the Copper CF (or wire) seals they are located inside of the bolt line.
Quote from: Rodal on 02/28/2015 10:40 pmDo you have a reference giving frequency, Q, power and thrust measurements for the Flight Thruster?This is the only reference I have for data for the Flight Thruster: http://emdrive.com/flightprogramme.html, I can't find a Q reported.Several of them for the "Flight Thruster Programme":Shawyer's CEAS 2009 paper stated, page 9:QuoteThe Flight thruster programme covers the design and development of a 300 Watt C Band flight thruster. This has a specified thrust of 85 mN, and a mass of 2.92Kg. Overall dimensions are 265mm diameter at the baseplate and a height of 164mm.Then in the 2010 Toulouse TECHNO DIS paper, page 8:QuoteDevelopment testing of the unit, up to a power of 600 W, is under way, and to date, has given a mean specific thrust of 330 mN/kW.[…]This is needed to ensure the input frequency matches the resonant frequency of the high Q (60,000) cavity, over the full input power range and the qualification temperature specification.And in the IAC 2013 paper, page 4:QuoteThe Dynamic performance of the non superconducting Flight Test model, manufactured and tested by SPR Ltd, and described in REF 3 [N.B.: 2010 Toulouse TECHNO DIS paper] was modeled with a cavity Qu = 50,000 and Fres=3.85 GHz.Finally the mean specific thrust of 326mN/kW over 19 test runs of up to 90 secs duration from 150 W to 450 W was found on the web page http://emdrive.com/flightprogramme.htmlAs well as the diagram which shows the maximum thrust achieved @ 450 W:
Do you have a reference giving frequency, Q, power and thrust measurements for the Flight Thruster?This is the only reference I have for data for the Flight Thruster: http://emdrive.com/flightprogramme.html, I can't find a Q reported.
The Flight thruster programme covers the design and development of a 300 Watt C Band flight thruster. This has a specified thrust of 85 mN, and a mass of 2.92Kg. Overall dimensions are 265mm diameter at the baseplate and a height of 164mm.
Development testing of the unit, up to a power of 600 W, is under way, and to date, has given a mean specific thrust of 330 mN/kW.[…]This is needed to ensure the input frequency matches the resonant frequency of the high Q (60,000) cavity, over the full input power range and the qualification temperature specification.
The Dynamic performance of the non superconducting Flight Test model, manufactured and tested by SPR Ltd, and described in REF 3 [N.B.: 2010 Toulouse TECHNO DIS paper] was modeled with a cavity Qu = 50,000 and Fres=3.85 GHz.
Quote from: lasoi on 03/01/2015 12:58 amIf the 265mm base diameter that Shawyer gave does in fact refer the the exterior diameter of the base plate and if the height is measured from the yellow arrows indicated in the aforementioned photo, which is the only way I can reconcile his figures with the photo, then my best guess for the inner resonance cavity is:224mm base diameter145mm top diameter164mm height (given by Shawyer).Here's the chart if anyone is interested, cluttered though it has admittedly become.Thanks! That brings that X number down to ~55. Still a very high mode, but 3.85GHz !
If the 265mm base diameter that Shawyer gave does in fact refer the the exterior diameter of the base plate and if the height is measured from the yellow arrows indicated in the aforementioned photo, which is the only way I can reconcile his figures with the photo, then my best guess for the inner resonance cavity is:224mm base diameter145mm top diameter164mm height (given by Shawyer).Here's the chart if anyone is interested, cluttered though it has admittedly become.
Quote from: Rodal on 03/01/2015 01:25 amMcCulloch's equation gives 148 milliNewtons for Shawyer's demo, comparing pretty well with Shawyer's reported measurements of 80 to 214 millinNewtons, see:http://physicsfromtheedge.blogspot.com/2015/02/mihsc-vs-emdrive-data-3d.htmlI understand that you need to use X=26 in your equation for Shawyer's Demo, also a high mode.On the other's hand McCulloch's equation is off by a factor >10 for NASA Eagleworks test results.That is an interesting fit.Of course I havn't seen Mike's derivation in 3D. I only follow the Equivalence argument the best I can w/o fudge factors and see what comes out. At the moment I think these are maximums if you have all the parameters and I like the NASA results because they seem to have eliminated more sources of error. Still, it may all be fiction which is what we want to find out.
McCulloch's equation gives 148 milliNewtons for Shawyer's demo, comparing pretty well with Shawyer's reported measurements of 80 to 214 millinNewtons, see:http://physicsfromtheedge.blogspot.com/2015/02/mihsc-vs-emdrive-data-3d.htmlI understand that you need to use X=26 in your equation for Shawyer's Demo, also a high mode.On the other's hand McCulloch's equation is off by a factor >10 for NASA Eagleworks test results.
@ RODALStill have question about the Shawyer "Demo" cavity w/ 174mN. What are the current estimates of the cone dimensions, frequency (3.85GHz?), and Q (6000 est?). When I put in TM02 and 450W, I get 174.8microN, rather than the 174milliN reported. I would like to recheck those numbers. Even w/ Q=45000, I need to get X up around (65 Very high mode) to get those numbers. Is that possible w/ 3.85GHz ??Thanks
Quote from: frobnicat on 03/04/2015 04:45 pm....It's not about faztek beams compliance. It's about introducing a tilt in the Z axis of rotation (the tilt is around the Y axis) so that the CoM Centre of Mass of the whole rotating assembly, which is not exactly on the Z axis (from the values given by Paul March) but behind the axis (X-) will be lowest when at rest equilibrium position and will have to climb the gravitational potential (ie work against) if it is to deviate from this position (by rotating around the Z axis). ....Thank you for taking the time to draw these excellent pictures. A picture is worth 1000 words.What compliance is responsible for the tilt in the Z axis of rotation around the Y axis) ? You state that the tilt is not due to the Faztek beam compliance (although if the Faztek beam would be compliant enough it certainly would tilt). If it is not due to the Faztek beam compliance, then my understanding is that you are saying that it is due to the compliance of the Riverhawk bearing. I had interpreted what was written about the Faztek bearings as providing a clamp condition (no tilt). Do you have quantitative information from the Riverhawk bearing manufacturer as to what is the magnitude of the torsional stiffness for a rotation around the Y axis provided by two Riverhawks that would allow such a tilt around the Y axis?NOTE: if such a tilt occurs, due to compliance of the Riverhawk bearings around the Y axis, it would be analogous to a flexural pendulum, with flexural stiffness given by the magnitude of the Riverhawk torsional stiffness for a rotation around the Y axis.
Quote from: frobnicat on 03/01/2015 09:12 pm...While I'm at it : is the plane in which the arm rotates kept as horizontal as possible (ie the axis of rotation as vertical as possible) or is there a small slope voluntarily introduced leading to some pendulum effect against g (for stabilisation or tuning purpose) ? That could explain the varying deviation (in µm) for the same calibration pulses thrusts. Also wondered if this is what was implied in this post :Quote from: Star-Drive...These thermally induced actions to the left requires the torque pendulum's arm to move to the right to maintain the balance of the torque pendulum's arm in the lab's 1.0 gee gravity field, since we also use the Earth's g-field to help null the pendulum's movements.......The design of our Torque pendulum follows what JPL and Busek Co did at their respective facility, see attached report from Busek. We found that if we tried to keep the arm completely horizontal though that the pendulum's neutral point would wonder erratically and make alignments near impossible. So yes I balance the pendulum arm so there is always a slight tilt in it, however this tilt angle magnitude is not controlled as well as it probably should. Best, Paul M.
...While I'm at it : is the plane in which the arm rotates kept as horizontal as possible (ie the axis of rotation as vertical as possible) or is there a small slope voluntarily introduced leading to some pendulum effect against g (for stabilisation or tuning purpose) ? That could explain the varying deviation (in µm) for the same calibration pulses thrusts. Also wondered if this is what was implied in this post :Quote from: Star-Drive...These thermally induced actions to the left requires the torque pendulum's arm to move to the right to maintain the balance of the torque pendulum's arm in the lab's 1.0 gee gravity field, since we also use the Earth's g-field to help null the pendulum's movements....
...These thermally induced actions to the left requires the torque pendulum's arm to move to the right to maintain the balance of the torque pendulum's arm in the lab's 1.0 gee gravity field, since we also use the Earth's g-field to help null the pendulum's movements....
Quote from: Rodal on 03/04/2015 05:08 pmQuote from: frobnicat on 03/04/2015 04:45 pm....It's not about faztek beams compliance. It's about introducing a tilt in the Z axis of rotation (the tilt is around the Y axis) so that the CoM Centre of Mass of the whole rotating assembly, which is not exactly on the Z axis (from the values given by Paul March) but behind the axis (X-) will be lowest when at rest equilibrium position and will have to climb the gravitational potential (ie work against) if it is to deviate from this position (by rotating around the Z axis). ....Thank you for taking the time to draw these excellent pictures. A picture is worth 1000 words.What compliance is responsible for the tilt in the Z axis of rotation around the Y axis) ? You state that the tilt is not due to the Faztek beam compliance (although if the Faztek beam would be compliant enough it certainly would tilt). If it is not due to the Faztek beam compliance, then my understanding is that you are saying that it is due to the compliance of the Riverhawk bearing. I had interpreted what was written about the Faztek bearings as providing a clamp condition (no tilt). Do you have quantitative information from the Riverhawk bearing manufacturer as to what is the magnitude of the torsional stiffness for a rotation around the Y axis provided by two Riverhawks that would allow such a tilt around the Y axis?NOTE: if such a tilt occurs, due to compliance of the Riverhawk bearings around the Y axis, it would be analogous to a flexural pendulum, with flexural stiffness given by the magnitude of the Riverhawk torsional stiffness for a rotation around the Y axis. And a thousand English words is a lot of sweat for me To answer your questions : while I consider looking for compliance aspects, both for faztek structural elements and for the bearings, there is no compliance implied by my latest post, the tilt would be voluntarily introduced for the whole experiment platform, including the bearing supporting fixed parts (the supporting axis is tilted, not just the arm or arm's rotation axis). That's how I read the answer of Star-Drive :....
Trying to post emdrive5.xls