Quote from: Rodal on 06/21/2015 07:18 pmQuote from: rfmwguy on 06/21/2015 06:44 pmAs promised, here is my video of the first test of my mechanical fulcrum. It will be used to show relative weight change in addition to a digital scale. Had some concerns about the digital scale alone, possibly being affected by the RF. The fulcrum is simply designed to be an alternate test method....Thank you for posting this !Great work.1) I don't know whether it is parallax due to the camera (I would like your feedback) but I saw bending of the wooden beam. Is the wooden beam compliant enought that the two water bottles are producing visible bending of the beam simply-supported by the knife edge? If so, you may have two sources of oscillation:a) lowest frequency oscillation: rigid body rotation of the beam around the knife edgeb) higher frequency oscillation: beam bending oscillations (there are an infinite number, but unless it was parallax I clearly saw beam bending : the first mode)Couldn't see whether the oscillations were due mainly to rigid body rotation or to bending, but based on the very long period of oscillation, it must be mainly due to rigid body rotation of the beam.2) If you cannot wait for the oscillations to dampen (>30 minutes ?) in the future, you may have to also include (oil or water) damping.Yes, the wood is bending and is a source of oscillation besides air currents and end weight rotation. It all becomes stable in abt 30 min, which is fine as my emdrive has abt 6 hour battery life.On the fulcrum, I cannot perform fast rep-rate testing, simply cw for long duration. The digital scale will be used for that.
Quote from: rfmwguy on 06/21/2015 06:44 pmAs promised, here is my video of the first test of my mechanical fulcrum. It will be used to show relative weight change in addition to a digital scale. Had some concerns about the digital scale alone, possibly being affected by the RF. The fulcrum is simply designed to be an alternate test method....Thank you for posting this !Great work.1) I don't know whether it is parallax due to the camera (I would like your feedback) but I saw bending of the wooden beam. Is the wooden beam compliant enought that the two water bottles are producing visible bending of the beam simply-supported by the knife edge? If so, you may have two sources of oscillation:a) lowest frequency oscillation: rigid body rotation of the beam around the knife edgeb) higher frequency oscillation: beam bending oscillations (there are an infinite number, but unless it was parallax I clearly saw beam bending : the first mode)Couldn't see whether the oscillations were due mainly to rigid body rotation or to bending, but based on the very long period of oscillation, it must be mainly due to rigid body rotation of the beam.2) If you cannot wait for the oscillations to dampen (>30 minutes ?) in the future, you may have to also include (oil or water) damping.
As promised, here is my video of the first test of my mechanical fulcrum. It will be used to show relative weight change in addition to a digital scale. Had some concerns about the digital scale alone, possibly being affected by the RF. The fulcrum is simply designed to be an alternate test method....
Quote from: rfmwguy on 06/21/2015 10:15 pmQuote from: Rodal on 06/21/2015 07:18 pmQuote from: rfmwguy on 06/21/2015 06:44 pmAs promised, here is my video of the first test of my mechanical fulcrum. It will be used to show relative weight change in addition to a digital scale. Had some concerns about the digital scale alone, possibly being affected by the RF. The fulcrum is simply designed to be an alternate test method....Thank you for posting this !Great work.1) I don't know whether it is parallax due to the camera (I would like your feedback) but I saw bending of the wooden beam. Is the wooden beam compliant enought that the two water bottles are producing visible bending of the beam simply-supported by the knife edge? If so, you may have two sources of oscillation:a) lowest frequency oscillation: rigid body rotation of the beam around the knife edgeb) higher frequency oscillation: beam bending oscillations (there are an infinite number, but unless it was parallax I clearly saw beam bending : the first mode)Couldn't see whether the oscillations were due mainly to rigid body rotation or to bending, but based on the very long period of oscillation, it must be mainly due to rigid body rotation of the beam.2) If you cannot wait for the oscillations to dampen (>30 minutes ?) in the future, you may have to also include (oil or water) damping.Yes, the wood is bending and is a source of oscillation besides air currents and end weight rotation. It all becomes stable in abt 30 min, which is fine as my emdrive has abt 6 hour battery life.On the fulcrum, I cannot perform fast rep-rate testing, simply cw for long duration. The digital scale will be used for that.Both the main rigid body rotation oscillation period and sensitivity (deviation/force) will depend on the height of centre of mass below the axis. It is below, otherwise the arm wouldn't be stable. The length of strings from which the water bottles hang don't count, since the strings are vertical (same torque around axis whether short or long). The position (height) at which the strings are attached just below the beam + bending downward of the beam are geometric factors that govern the main dynamic and static equilibrium (sensitivity). Since the beam seems very compliant, the periodic variation of bending (mode b, as per Rodal) will significantly alter the parameters of mode a) : there will be coupling between the two modes a) and b). Maybe it's possible at small cost and small added weight to use a stiffer beam, or make this one stiffer, for instance by triangulating (vertical "mast" fixed orthogonal at centre, two cables slanting from top of it toward both ends of beam).
Quote from: rfmwguy on 06/21/2015 10:15 pmQuote from: Rodal on 06/21/2015 07:18 pmQuote from: rfmwguy on 06/21/2015 06:44 pmAs promised, here is my video of the first test of my mechanical fulcrum. It will be used to show relative weight change in addition to a digital scale. Had some concerns about the digital scale alone, possibly being affected by the RF. The fulcrum is simply designed to be an alternate test method....Thank you for posting this !Great work.Since the beam seems very compliant, the periodic variation of bending (mode b, as per Rodal) will significantly alter the parameters of mode a) : there will be coupling between the two modes a) and b). Maybe it's possible at small cost and small added weight to use a stiffer beam, or make this one stiffer, for instance by triangulating (vertical "mast" fixed orthogonal at centre, two cables slanting from top of it toward both ends of beam).PERFECT!!! I was trying to play catch up asI was away and was just thinking of ways you could stiffen it. I think the cable idea is perfect. Nice.Shell
Quote from: Rodal on 06/21/2015 07:18 pmQuote from: rfmwguy on 06/21/2015 06:44 pmAs promised, here is my video of the first test of my mechanical fulcrum. It will be used to show relative weight change in addition to a digital scale. Had some concerns about the digital scale alone, possibly being affected by the RF. The fulcrum is simply designed to be an alternate test method....Thank you for posting this !Great work.Since the beam seems very compliant, the periodic variation of bending (mode b, as per Rodal) will significantly alter the parameters of mode a) : there will be coupling between the two modes a) and b). Maybe it's possible at small cost and small added weight to use a stiffer beam, or make this one stiffer, for instance by triangulating (vertical "mast" fixed orthogonal at centre, two cables slanting from top of it toward both ends of beam).PERFECT!!! I was trying to play catch up asI was away and was just thinking of ways you could stiffen it. I think the cable idea is perfect. Nice.Shell
Quote from: rfmwguy on 06/21/2015 06:44 pmAs promised, here is my video of the first test of my mechanical fulcrum. It will be used to show relative weight change in addition to a digital scale. Had some concerns about the digital scale alone, possibly being affected by the RF. The fulcrum is simply designed to be an alternate test method....Thank you for posting this !Great work.Since the beam seems very compliant, the periodic variation of bending (mode b, as per Rodal) will significantly alter the parameters of mode a) : there will be coupling between the two modes a) and b). Maybe it's possible at small cost and small added weight to use a stiffer beam, or make this one stiffer, for instance by triangulating (vertical "mast" fixed orthogonal at centre, two cables slanting from top of it toward both ends of beam).
@Rodal - I have: BIG DIAMETER = 0.27246 m SMALL DIAMETER = 0.068115 m LENGTH = 0.4890240258390259 mPardon the extra digits from the calculation.Running in 3-D with bandwidth opened up to 0.5 * drive frequency (drive = ~1.95GHz), Meep finds 4 frequencies:1.58530024E+0091.83409637E+0092.08402579E+0092.33698507E+009 Hz Q - in order620.675008923133.41473139131211.3296422825141.0133154386 This is electric excitation with antenna = 0.2 * wavelength, perpendicular to and centered on the central axis of rotation.OK - I just read the rest of your post. I'll look for the location of the antenna in the Brady cone, and put it there. But as I recall, that was for exciting a TM mode?
Quote from: A_M_Swallow on 06/21/2015 10:36 pmDear rfmwguy, a table to put the camera down on may make adjusting things easier as it will allow you to use both hands.A table or a tripod. Unless you are filming with your cell phone
Dear rfmwguy, a table to put the camera down on may make adjusting things easier as it will allow you to use both hands.
I attach my report first attachment below, titled:Cut-off of Resonant Modes in Truncated Conical CavitiesConclusions...
Quote from: Rodal on 06/21/2015 08:07 pmI attach my report first attachment below, titled:Cut-off of Resonant Modes in Truncated Conical CavitiesConclusions...This is a great piece of work Jose. It shows what can be learned when a problem thoroughly tackled and we don't just copy and paste what someone else did. I've got to analyze this myself some more. I'm working on my DC analysis and I've made significant progress. It's not ready yet, but I think it will be interesting.Todd
Quote from: aero on 06/21/2015 11:03 pmQuote from: A_M_Swallow on 06/21/2015 10:36 pmDear rfmwguy, a table to put the camera down on may make adjusting things easier as it will allow you to use both hands.A table or a tripod. Unless you are filming with your cell phone @rfmwguy: How many kilos did you plan hanging off that splendid piece of wood? I seem to recall you wanted to make this self-contained and battery operated (or was that TheTraveller?).How much RF power will you use?For what sort of thrust magnitude are you planning?
Quote from: deltaMass on 06/22/2015 02:10 amQuote from: aero on 06/21/2015 11:03 pmQuote from: A_M_Swallow on 06/21/2015 10:36 pmDear rfmwguy, a table to put the camera down on may make adjusting things easier as it will allow you to use both hands.A table or a tripod. Unless you are filming with your cell phone @rfmwguy: How many kilos did you plan hanging off that splendid piece of wood? I seem to recall you wanted to make this self-contained and battery operated (or was that TheTraveller?).How much RF power will you use?For what sort of thrust magnitude are you planning?Budget is 1.5 kg 8 watts and 12 cubic inches
Quote from: WarpTech on 06/18/2015 08:08 pmJust came across a very interesting paper;http://arxiv.org/pdf/0708.3519.pdfPhotons inside a waveguide as massive particlesZhi-Yong Wang1, Cai-Dong Xiong"In the paper, we show that there exists a close analogy between the behavior of deBroglie matter waves and that of electromagnetic waves inside a hollow waveguide, such that the guided photons can be treated as free massive particles subject to a relativistic quantum-mechanical equation. Inspired by the effective rest mass of guided photons and the zitterbewegung phenomenon of the Dirac electron, at variance with the well-known Higgs mechanism we present some different heuristic ideas on the origin of mass."So, apparently photons in a waveguide may be treated identically to De Broglie waves of massive particles. The photons have a rest mass determined by the waveguide cut-off where vg => 0;mphoton = h/cλcand have relativistic momentum;p = mphoton*vg/√(1 - (vg/c)2)As the waves reach the cut-off end of the waveguide, their momentum goes to zero and the frustum must gain that amount of rest mass. This process should happen with a magnetron, because the output is a Negative E-field, pulsed at 60Hz (or 50Hz) and this negative value exponentially decays to zero. The magnetron's microwaves have a negative DC bias, right out of the gun.http://www.cpii.com/docs/related/2/Mag%20tech%20art.pdfI believe that this process stores mass at the front of the frustum that builds over time, walking the CM forward until there is enough pressure to push it. The resonant microwaves, IMO like Greg Egan, have nothing to do with the thrust. The Q when using a magnetron however, may be proportional the stored DC current level as well as the resonance since both will grow together until heat losses overcome the addition of more current. It is essentially, charging up an inductor, L,dI(t) = (V/L)dtIn this case, f = 60Hz, not GHz. The force dF = B.H*dS (S for area), is due to the B-field pressure, which escapes through the copper because it is DC. The AC skin effect does not apply so the field cannot be shielded by copper. Todd
Just came across a very interesting paper;http://arxiv.org/pdf/0708.3519.pdfPhotons inside a waveguide as massive particlesZhi-Yong Wang1, Cai-Dong Xiong"In the paper, we show that there exists a close analogy between the behavior of deBroglie matter waves and that of electromagnetic waves inside a hollow waveguide, such that the guided photons can be treated as free massive particles subject to a relativistic quantum-mechanical equation. Inspired by the effective rest mass of guided photons and the zitterbewegung phenomenon of the Dirac electron, at variance with the well-known Higgs mechanism we present some different heuristic ideas on the origin of mass."
As the waves reach the cut-off end of the waveguide, their momentum goes to zero and the frustum must gain that amount of rest mass. This process should happen with a magnetron, because the output is a Negative E-field, pulsed at 60Hz (or 50Hz) and this negative value exponentially decays to zero.
.. I'm working on my DC analysis and I've made significant progress. It's not ready yet, but I think it will be interesting.Todd
Dr. Rodal very cool videos. I'm sure it' a dumb idea but it comes to mind for a low cost setup for the baby EM drive... Can we use sound waves to lock them into a controlled spin? Could they possibly Have 2 setups contained in 2 separate large plastic or glass containments (to reduce problems with drafts), then use sound to control the initial starting conditions of each setup... cheaply, you could probably use a magnet to hold them at an identical starting position then remove it and then start to spin it with sound... I think you could control the setup with decent precision and have them operating synchronously... We use some setup for the base that damps vibrations or possibly have both setups hang from the ceiling? With both devices synced up we kill the sound and then we turn one of the baby EM Drives on and measure any significant deviation between the two setups. We could also capture video of both setups and analyze the difference with video software... all you'd need for a basic setup are 2 displays both provided the same video source that has a clock counting up at idk 120hz and then you can have 2 individual cameras take the video and syncing up and comparing them later would be simple.Would the expelled air from the bottle or whatever open container is used as a thruster be too chaotic to have in a closed environment? Would it overwhelm the possibility of making any significant measurements or would each setup operate in a relatively controlled manner?
...I can't recall anyone doing any deliberate modulation/pulsing of the power input so I want to highlight this for everyone's consideration.(I am catching up on this thread so apologies for the late question for this post.)
Quote from: rfmwguy on 06/22/2015 03:28 amQuote from: deltaMass on 06/22/2015 02:10 amQuote from: aero on 06/21/2015 11:03 pmQuote from: A_M_Swallow on 06/21/2015 10:36 pmDear rfmwguy, a table to put the camera down on may make adjusting things easier as it will allow you to use both hands.A table or a tripod. Unless you are filming with your cell phone @rfmwguy: How many kilos did you plan hanging off that splendid piece of wood? I seem to recall you wanted to make this self-contained and battery operated (or was that TheTraveller?).How much RF power will you use?For what sort of thrust magnitude are you planning?Budget is 1.5 kg 8 watts and 12 cubic inches12 cubic inches of thrust should be readily detectable with your set-up I think.
...Sorry, thrust estimate in the 185 mg range I believe is what the spreadsheet said...snarky comment accepted