....In my opinion such a low tempo low priority side project that could probably be fully funded from the couch change from break room lounge chairs should not be micromanaged like it's a multi-billion dollar resource intensive space probe project and put under deadline pressure like that.
Quote from: Mulletron on 02/27/2015 09:00 pmhttp://www.ebay.com/itm/AERCOM-Microwave-RF-Isolator-Circulator-2-4GHz-20dB-isolation-Low-I-L-TESTED-/281549538390?ssPageName=ADME:L:OU:US:1120Picked up one of these puppies on Ebay to protect my amp. Another example of broken time reversal symmetry in action.Got about an oz of very expensive liquid metal from here:http://www.amazon.com/Gallium-Indium-Eutectic-GaInSn-68-5%25/dp/B00KN92MWW/ref=sr_1_3?ie=UTF8&qid=1425074693&sr=8-3&keywords=galinstanSo back to the copper from way back: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326742#msg1326742...Been working with the supplier with a machine shop I posted about way back:http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326669#msg1326669 I'm going that route. The quote I got is: price: $120.00 layout + $51.63 for part + freight. So I have to pay the layout, then anyone else who wants one of these: but built in 16oz copper, with a smooth butt seam inside, and 1/4" flange around edges, can get one for about 50 bucks plus shipping. If all this works out, it'll fulfill my goal of making a replication by DIYers easier. For me, paying the layout plus price about breaks even with buying the sheet myself and fumblefuddeling around trying to solder up a cone at home. So I'm happy. I'll get back with more later, when the items are at home.Hello Mulletron,Hope you'll be able to conduct another test, and I guess there are many other people like me who encourage you to continue.How do you intend to measure the (very tiny) thrust ? Reading back NASA's paper, it seems they had to run the experiment in a lab with complex (and expensive) tools to remove all parasite effects that would interfere with the thrust from the apparatus. Maybe you have access to such equipment ?--Mathieu
http://www.ebay.com/itm/AERCOM-Microwave-RF-Isolator-Circulator-2-4GHz-20dB-isolation-Low-I-L-TESTED-/281549538390?ssPageName=ADME:L:OU:US:1120Picked up one of these puppies on Ebay to protect my amp. Another example of broken time reversal symmetry in action.Got about an oz of very expensive liquid metal from here:http://www.amazon.com/Gallium-Indium-Eutectic-GaInSn-68-5%25/dp/B00KN92MWW/ref=sr_1_3?ie=UTF8&qid=1425074693&sr=8-3&keywords=galinstanSo back to the copper from way back: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326742#msg1326742...Been working with the supplier with a machine shop I posted about way back:http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326669#msg1326669 I'm going that route. The quote I got is: price: $120.00 layout + $51.63 for part + freight. So I have to pay the layout, then anyone else who wants one of these: but built in 16oz copper, with a smooth butt seam inside, and 1/4" flange around edges, can get one for about 50 bucks plus shipping. If all this works out, it'll fulfill my goal of making a replication by DIYers easier. For me, paying the layout plus price about breaks even with buying the sheet myself and fumblefuddeling around trying to solder up a cone at home. So I'm happy. I'll get back with more later, when the items are at home.
Quote from: MathieuA on 02/28/2015 06:30 pmQuote from: Mulletron on 02/27/2015 09:00 pmhttp://www.ebay.com/itm/AERCOM-Microwave-RF-Isolator-Circulator-2-4GHz-20dB-isolation-Low-I-L-TESTED-/281549538390?ssPageName=ADME:L:OU:US:1120Picked up one of these puppies on Ebay to protect my amp. Another example of broken time reversal symmetry in action.Got about an oz of very expensive liquid metal from here:http://www.amazon.com/Gallium-Indium-Eutectic-GaInSn-68-5%25/dp/B00KN92MWW/ref=sr_1_3?ie=UTF8&qid=1425074693&sr=8-3&keywords=galinstanSo back to the copper from way back: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326742#msg1326742...Been working with the supplier with a machine shop I posted about way back:http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326669#msg1326669 I'm going that route. The quote I got is: price: $120.00 layout + $51.63 for part + freight. So I have to pay the layout, then anyone else who wants one of these: but built in 16oz copper, with a smooth butt seam inside, and 1/4" flange around edges, can get one for about 50 bucks plus shipping. If all this works out, it'll fulfill my goal of making a replication by DIYers easier. For me, paying the layout plus price about breaks even with buying the sheet myself and fumblefuddeling around trying to solder up a cone at home. So I'm happy. I'll get back with more later, when the items are at home.Hello Mulletron,Hope you'll be able to conduct another test, and I guess there are many other people like me who encourage you to continue.How do you intend to measure the (very tiny) thrust ? Reading back NASA's paper, it seems they had to run the experiment in a lab with complex (and expensive) tools to remove all parasite effects that would interfere with the thrust from the apparatus. Maybe you have access to such equipment ?--MathieuGoing to do a Cavendish experiment: http://www.intalek.com/Index/Projects/Research/CavendishExperiment.htmhttps://www.fourmilab.ch/gravitation/foobar/ (link is down right now, hope it comes back)Don't need expensive gear. You can do amazing things with some fishing line and ingenuity.
Does anyone clearly understand the reaction force R vs opposite thrust T in Shawyer's newest document "A Note on the Principles of EmDrive force measurement" that I attach to this message? Especially, the problem of the "restrained thruster" of fig. 3 where no movement could be detected at all?Shawyer seems to imply that the EmDrive needs to experience an acceleration (even the slightest one) to create a force that would me measurable. A fully restrained cavity would not move at all. It reminds me of the the Mach effect thruster, where according to Woodward the material needs to undergo a proper acceleration while being energized, otherwise the transient mass fluctuation does not occur. Evidently, Eagleworks' RF resonant cavity test article is fixed to the rest of the apparatus, but Shawyer explains any small thermal effect makes the walls move hence the center of gravity of the cavity also move a bit, and this would be enough for any small force to appear.
Thanks you two. I was under the bad impression I was silly for not understanding Shawyer's explanations.
If one looks closely at the contour plots of the TM modes in http://forum.nasaspaceflight.com/index.php?topic=36313.msg1340906#msg1340906, one will notice that Egan's contour plots have the maximum of the magnetic field occurring at the cone surface while my contour plots have the maximum of the magnetic field occurring at a distance from the cone's surface. I have examined the source of this discrepancy. My conclusion is that Egan's plots are incorrect regarding this feature, and they are inconsistent with the equations on Egan's post. If anybody is interested to know why, I can post the mathematical proof and discussion for this conclusion.
Quote from: flux_capacitor on 03/03/2015 09:35 pmThanks you two. I was under the bad impression I was silly for not understanding Shawyer's explanations.There is an easy way to test this.Paul March said that they need to maximize the thrust for the experiment to be verified at NASA Glenn.Paul March measures the displacement vs. time with an optical method as previously discussed in detail by zen-in "Philtec D63 fiber-optic displacement sensor measures distance from its target mirror by measuring the intensity of the reflected light.".If Shawyer is correct that the less restraint the better, then Paul March could lessen the current restraint in his experiments by replacing the RiverHawk bearing with another one (if available) having less stiffness. If Shawyer is correct, the decrease in restraint should produce an increase in the measured response.
....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.
Do you mean that this might actually be right? I've ignored the fields that look like this because I thought they were supposed to be symmetric.
Quote from: Star-Drive on 03/02/2015 12:21 amQuote from: frobnicat on 03/01/2015 09:12 pmDr. March,I'm trying to model various aspects of the whole system to put upper bounds on thermal effects, and possibly also reconstruct the thrust(t) original signal from the distance(t) given in the charts. It would be a nice boost to this (amateur level) effort if you could confirm either :- That the flexure bearings have a stiffness of 0.007 in-Lb/deg ? Each ? Both together ? Do you know the exact model reference ?- That the vertical scale in the charts (indicated in µm, around 500) are relevant or not relevant.I ask this question because I find a contradiction between the stiffness around the vertical axis and the recorded deviation from the 30µN calibration pulses (at .007 in-Lb/deg the deviation of the linear displacement sensor would be above 40µm, at .014 in-Lb/deg still above 20µm). The readings amount for between 1 to 2.5 µm for the 30µN calibration pulses. So I'm stuck.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....ThanksFrobnicat:To answer your question:" - That the flexure bearings have a stiffness of 0.007 in-Lb/deg ? Each ? Both together ? Do you know the exact model reference?"The two torsion bearings used in or torque pendulum are supposed to have a stiffness of 0.007 in-Lb/deg, +/-10% and is made by the Riverhawk Co. in New York USA. As to their model number find the data sheet for same attached. "- That the vertical scale in the charts (indicated in µm, around 500) are relevant or not relevant."The Philtec D63 fiber-optic displacement sensor measures distance from its target mirror in microns, so the numbers on the left hand side of the force plots measure the distance from the end of the fiber-optic laser head to its mirror target mounted on the torque pendulum arm. The data sheet for same is attached."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 stabilization or tuning purpose)?"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.Thank you very much for those precious informations. The tilt angle magnitude can probably be inferred from the deviation against the calibration pulses, if we can model the gravitational pendulum component on top of the flexure bearing restoring torque component.For that we need to know :Mass of : frustum, without dielectric : 1.606 kg microwave power amplifier : below 8kg ? faztek horizontal beam : 2.18 Lb (from 1.09Lb/Ft) ? Ideally, Total mass with a rough estimate of position of each part... Distances along the arm from vertical axis of rotation to the centre of : Long end of arm (frustum side) : 15.5'' Short end of arm (amplifier side) : 8.5'' Frustum : 15.5 - 4 = 11.5'' ? Electrostatic Fins Calibration System : 15.5-4 = 11.5'' ? Linear Displacement Sensor : 15.5-1 = 14.5'' ? microwave power amplifier : between 4.25'' and 8.5'' ? Stiffness of flexure bearings : .014 in-Lb/deg total (2 times .007 each)In short : what is the total mass of the whole rotating assembly, where is the centre of mass of the whole rotating assembly relative to axis of rotation, and what is the moment of inertia around the (almost) vertical axis of rotation (for the later, to assess the dynamics and not just the equilibrium).green : explicitly provided valueorange : inferred from pictures or derived by me from faztek sellers, to be confirmedred : not found, do we have better than bounds for those ?
Quote from: frobnicat on 03/01/2015 09:12 pmDr. March,I'm trying to model various aspects of the whole system to put upper bounds on thermal effects, and possibly also reconstruct the thrust(t) original signal from the distance(t) given in the charts. It would be a nice boost to this (amateur level) effort if you could confirm either :- That the flexure bearings have a stiffness of 0.007 in-Lb/deg ? Each ? Both together ? Do you know the exact model reference ?- That the vertical scale in the charts (indicated in µm, around 500) are relevant or not relevant.I ask this question because I find a contradiction between the stiffness around the vertical axis and the recorded deviation from the 30µN calibration pulses (at .007 in-Lb/deg the deviation of the linear displacement sensor would be above 40µm, at .014 in-Lb/deg still above 20µm). The readings amount for between 1 to 2.5 µm for the 30µN calibration pulses. So I'm stuck.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....ThanksFrobnicat:To answer your question:" - That the flexure bearings have a stiffness of 0.007 in-Lb/deg ? Each ? Both together ? Do you know the exact model reference?"The two torsion bearings used in or torque pendulum are supposed to have a stiffness of 0.007 in-Lb/deg, +/-10% and is made by the Riverhawk Co. in New York USA. As to their model number find the data sheet for same attached. "- That the vertical scale in the charts (indicated in µm, around 500) are relevant or not relevant."The Philtec D63 fiber-optic displacement sensor measures distance from its target mirror in microns, so the numbers on the left hand side of the force plots measure the distance from the end of the fiber-optic laser head to its mirror target mounted on the torque pendulum arm. The data sheet for same is attached."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 stabilization or tuning purpose)?"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.
Dr. March,I'm trying to model various aspects of the whole system to put upper bounds on thermal effects, and possibly also reconstruct the thrust(t) original signal from the distance(t) given in the charts. It would be a nice boost to this (amateur level) effort if you could confirm either :- That the flexure bearings have a stiffness of 0.007 in-Lb/deg ? Each ? Both together ? Do you know the exact model reference ?- That the vertical scale in the charts (indicated in µm, around 500) are relevant or not relevant.I ask this question because I find a contradiction between the stiffness around the vertical axis and the recorded deviation from the 30µN calibration pulses (at .007 in-Lb/deg the deviation of the linear displacement sensor would be above 40µm, at .014 in-Lb/deg still above 20µm). The readings amount for between 1 to 2.5 µm for the 30µN calibration pulses. So I'm stuck.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....Thanks
...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....
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.