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#1600
by
RFPlumber
on 11 Jan, 2016 03:15
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I am truly surprised by the magnitude of presumably thermal effects which accompany these tests at ambient pressure. To the point that I think I can describe a sure way of constructing a working "EmDrive" which will successfully pass most of the tests... All it takes is a reasonably hermetical frustum with a pin sized hole at one side.
I plan to address the pin hole hot air jet concern in 2 ways:
1) real time monitoring of internal frustum pressure.
2) acceleration times of 10 to 30 minutes continually operating / accelerating.
And then some other air-related effect will bite you. 
Like the attached "chimney" one for my setup, which I am starting to suspect is very real (and is amplified by the large asymmetrical cavity on the platform).
You need to show the upward heat rising from the frustum, that is assuming it was taking the Rf power. What you are showing is the case if the frustum had a VERY bad VSWR and all the Rf power was reflected back to the amp and thermalised there.
With all due respect, my Rf Amp is consuming 10 Amp @14 Volts (140W) while delivering only 30W of RF. The amp heat spreader plate gets seriously hot very fast regardless of load (even when using a dummy 50 Ohm one). So this effect has nothing to do with VSWR.
Real time monitoring of fwd/reflected power is definitely helpful, it is true that I did not have it during this run. It is certainly possible that the cavity was getting out of resonance just exactly during the test run while showing good S11 both right before and right after one. The only change is replacing the cable going from coupled port (-20 dBm) of the directional coupler to the power meter sensor with an SMA-sized 50 Ohm load (and then back to the sensor after the run).
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#1601
by
meberbs
on 11 Jan, 2016 04:02
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Guide wavelength as normally defined is not a concept that even makes sense for a resonating cavity, unless I have missed something where you have given a definition that applies to a closed cavity.
Cutoff of the small end is also not clearly defined. You would have to define something such as lowest resonant frequency that near the small end looks similar to one of the mode types for a cylindrical cavity. (A good rigorous definition of this would be difficult)
For some geometry ratios, there could be resonant frequencies of the cavity that would have mode shapes that appear different from those of a cylindrical cavity. Without doing math, it is easy to show that resonances could exist below your calculation for a small end cutoff, by considering the limit where you take the small end diameter to 0, resulting in a cone. This would still be able to resonate without requiring x-ray frequencies. Whether these types of modes would be better or worse for thrust generation (assuming there is any to begin with) is completely unknown, since no experiments have claimed to excite that type of mode. Shawyer's advice is only worth taking for things he has done experiments on, due to the issues with his "theory". I have seen no reports of him actually experimenting with a "small end cut-off" mode shape.
Clearly Roger has experimentally discovered what works and what does not. His 0.82 cutoff rule is one example.
I haven't seen any evidence of comparative experiments like I described being done, and until I see results from such experiments, I will not make conclusions about which modes work best. (Also, just getting some definitive and consistent thrust measurements comes before trying to do this kind of experiment anyway.)
Do you have any response to the rest of my post, where I pointed out that there is no definition for small end cut-off or guide wavelength for a frustum resonator? I would be very interested to see a workable definition for either of those concepts, since you keep asking people to make calculations of them.
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#1602
by
SteveD
on 11 Jan, 2016 04:03
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The Voith trademark for EMDrive was filed in 2008. Given the date, I would expect that it does not refer to a Shawyer effect drive.
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#1603
by
Tellmeagain
on 11 Jan, 2016 04:20
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One is welcome to infer one's own conclusions from this data. I, for one, definitely do not see any directional force, let along one being reasonably coincidental with applied RF power. Yet, despite all noise and oscillations I can easily see the electrostatic force, which, btw, in this setup is only around 300-400 uN.
I think you have one way to deal with the amplifier thermal problem. You can use ice and water mix like that in our Lorentz force paper. 1 kg of ice can support your experiment long enough to get meaningful results.
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#1604
by
Dortex
on 11 Jan, 2016 04:30
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It's been far too long since I've stopped lurking here! What have I missed? Can I strap a drive on my Velomobile and move forward with my all-terrain, personal spacecraft business?
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#1605
by
SteveD
on 11 Jan, 2016 04:33
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RFplumber, can we get some better picture of the frustum? I can't tell if the end plates are warped or not in the attached picture. Do you have VNA data?
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#1606
by
RFPlumber
on 11 Jan, 2016 05:03
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RFplumber, can we get some better picture of the frustum? I can't tell if the end plates are warped or not in the attached picture. Do you have VNA data?
I just checked it out. The bigger end is warped by about 1mm over the diameter (the center is more outwards than the corners), the smaller end is warped in a similar way by about 0.5 mm. At the same time both end plates are surprisingly parallel to each other - center length measured at each of 4 sides between the endplates matches within 1 mm.
Sorry, I do now have a vector NA. Scans from a scalar NA have already been posted here
http://forum.nasaspaceflight.com/index.php?topic=39004.msg1471219#msg1471219
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#1607
by
Rodal
on 11 Jan, 2016 14:49
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As we often discuss apparent violation of energy conservation by extrapolation of claimed EMDrive experimental results, here we have this interesting news:
Canadian inventor gets US patent in case related to apparent violation of energy conservationGets US patent (granted last week), for a super transformer (*) related to another device that apparently violates conservation of energy:
US patent # 9,230,730
Grant date 2016-01-05Most likely there is an explanation for the Perepiteia effect that does not violate the law of energy conservation (see Prof. Zahn's statement, below).
https://patents.google.com/patent/US9230730B2/en___________________
(*) "a transformer which displays virtually no primary input current increase from no-load to on-load and
an on-load power factor of zero for a purely resistive load"
in communications with science writer David Bradley of ScienceBase, Heins made claims of up to 7000% efficiency for the bi-toroidal transformer
[I could not find the above-quoted article by David Bradley]
https://en.wikipedia.org/wiki/PerepiteiaPerepiteia's process begins by overloading the generator to get a current, which typically causes the wire coil to build up a large electromagnetic field. Usually, this kind of electromagnetic field creates an effect called the back electromotive force (back EMF) due to Lenz's law. The effect should repel the spinning magnets on the rotor, and slow them down until the motor stops completely, in accordance with the law of conservation. However, instead of stopping, the rotor accelerates - i.e. the magnetic friction did not repel the magnets and wire coil. Heins states that the steel rotor and driveshaft had conducted the magnetic resistance away from the coil and back into the electric motor. In effect, the back EMF was boosting the magnetic fields used by the motor to generate electrical energy and cause acceleration. The faster the motor accelerated, the stronger the electromagnetic field it would create on the wire coil, which in turn would make the motor go even faster. Heins seemed to have created a positive feedback loop. To confirm the theory, Heins replaced part of the driveshaft with plastic pipe that wouldn't conduct the magnetic field. There was no acceleration.
In a subsequent e-mail to ( Canadian inventor) Heins, (MIT Professor of Electrical Engineering) Zahn wrote that: "Any talk of perpetual motion, over unity efficiency, etc. discredits you, now me, and your ideas." Zahn further stated that he would not endorse Heins' device until "the foolishness is stopped of hinting that your motor violates fundamental laws of physics"
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#1608
by
rfmwguy
on 11 Jan, 2016 15:05
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After much research, I've determined that this is the best way to construct a frustum...seamless at the small diameter:
This horizontal lathe was modified to include a spinning "form", or shape, that the copper sheet "folds" over. The left side of the lathe uses a compression disc that snugs the copper sheet onto the top of the form, which could be any shape. A frustum would be one of the more simpler forms to have constructed.
The brass-smith said he could make a bell/frustum but it would have a brazed seam that would have to be ground/polished away. More labor costs.
The cost is similar for both ways to do it. Looks like the spinning copper method is superior. Interior polishing would be needed.
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#1609
by
rfmwguy
on 11 Jan, 2016 16:04
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As we often discuss apparent violation of energy conservation by extrapolation of claimed EMDrive experimental results, here we have this interesting news:
Canadian inventor gets US patent in case related to apparent violation of energy conservation
Gets US patent (granted last week), for a super transformer (*) related to another device that apparently violates conservation of energy:
US patent # 9,230,730
Grant date 2016-01-05
Most likely there is an explanation for the Perepiteia effect that does not violate the law of energy conservation (see Prof. Zahn's statement, below).
https://patents.google.com/patent/US9230730B2/en
___________________
(*) "a transformer which displays virtually no primary input current increase from no-load to on-load and an on-load power factor of zero for a purely resistive load"
in communications with science writer David Bradley of ScienceBase, Heins made claims of up to 7000% efficiency for the bi-toroidal transformer
https://en.wikipedia.org/wiki/Perepiteia
Perepiteia's process begins by overloading the generator to get a current, which typically causes the wire coil to build up a large electromagnetic field. Usually, this kind of electromagnetic field creates an effect called the back electromotive force (back EMF) due to Lenz's law. The effect should repel the spinning magnets on the rotor, and slow them down until the motor stops completely, in accordance with the law of conservation. However, instead of stopping, the rotor accelerates - i.e. the magnetic friction did not repel the magnets and wire coil. Heins states that the steel rotor and driveshaft had conducted the magnetic resistance away from the coil and back into the electric motor. In effect, the back EMF was boosting the magnetic fields used by the motor to generate electrical energy and cause acceleration. The faster the motor accelerated, the stronger the electromagnetic field it would create on the wire coil, which in turn would make the motor go even faster. Heins seemed to have created a positive feedback loop. To confirm the theory, Heins replaced part of the driveshaft with plastic pipe that wouldn't conduct the magnetic field. There was no acceleration.
In a subsequent e-mail to ( Canadian inventor) Heins, (MIT Professor of Electrical Engineering) Zahn wrote that: "Any talk of perpetual motion, over unity efficiency, etc. discredits you, now me, and your ideas." Zahn further stated that he would not endorse Heins' device until "the foolishness is stopped of hinting that your motor violates fundamental laws of physics"
I've always found this over-unity motor stuff interesting...but that's about it.
I did have one observation on the magnetron modification experiments with a few small neodymium magnets placed against the ring magnets...once heated over 100 degrees C, the small magnets lost much of their strength.
It returned once they cooled to room temp. How did I notice this? When I moved the magnets around the ring magnet, it was FAR easier to do when they were hot.
Back EMF is probably highly dependent on temperature. I did not see any thermal testing of this guys assembly.
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#1610
by
SteveD
on 11 Jan, 2016 16:09
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As we often discuss apparent violation of energy conservation by extrapolation of claimed EMDrive experimental results, here we have this interesting news:
Canadian inventor gets US patent in case related to apparent violation of energy conservation
Gets US patent (granted last week), for a super transformer (*) related to another device that apparently violates conservation of energy:
US patent # 9,230,730
Grant date 2016-01-05
Most likely there is an explanation for the Perepiteia effect that does not violate the law of energy conservation (see Prof. Zahn's statement, below).
https://patents.google.com/patent/US9230730B2/en
___________________
(*) "a transformer which displays virtually no primary input current increase from no-load to on-load and an on-load power factor of zero for a purely resistive load"
in communications with science writer David Bradley of ScienceBase, Heins made claims of up to 7000% efficiency for the bi-toroidal transformer
https://en.wikipedia.org/wiki/Perepiteia
Perepiteia's process begins by overloading the generator to get a current, which typically causes the wire coil to build up a large electromagnetic field. Usually, this kind of electromagnetic field creates an effect called the back electromotive force (back EMF) due to Lenz's law. The effect should repel the spinning magnets on the rotor, and slow them down until the motor stops completely, in accordance with the law of conservation. However, instead of stopping, the rotor accelerates - i.e. the magnetic friction did not repel the magnets and wire coil. Heins states that the steel rotor and driveshaft had conducted the magnetic resistance away from the coil and back into the electric motor. In effect, the back EMF was boosting the magnetic fields used by the motor to generate electrical energy and cause acceleration. The faster the motor accelerated, the stronger the electromagnetic field it would create on the wire coil, which in turn would make the motor go even faster. Heins seemed to have created a positive feedback loop. To confirm the theory, Heins replaced part of the driveshaft with plastic pipe that wouldn't conduct the magnetic field. There was no acceleration.
In a subsequent e-mail to ( Canadian inventor) Heins, (MIT Professor of Electrical Engineering) Zahn wrote that: "Any talk of perpetual motion, over unity efficiency, etc. discredits you, now me, and your ideas." Zahn further stated that he would not endorse Heins' device until "the foolishness is stopped of hinting that your motor violates fundamental laws of physics"
Is that the same effect as the Steon Orb-O is suppose to use? I note that Steon has backed off their perpetual motion claim and are now marketing ss some kind of extended life battery (I also note that the Steon device is "sold out" and that nobody has reported receiving one for testing).
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#1611
by
Rodal
on 11 Jan, 2016 16:12
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..
I did have one observation on the magnetron modification experiments with a few small neodymium magnets placed against the ring magnets...once heated over 100 degrees C, the small magnets lost much of their strength.
It returned once they cooled to room temp. How did I notice this? When I moved the magnets around the ring magnet, it was FAR easier to do when they were hot.
Back EMF is probably highly dependent on temperature. I did not see any thermal testing of this guys assembly.
The case is also interesting because we have the US Patent Office still awarding (just last week) a US patent for an invention claiming "zero power factor for purely resistive load" (and separately to the press claiming 7000% efficiency).
Showing that getting a US patent awarded does not mean that the invention has to be consistent with the laws of Physics (nothing new to those familiar with US patent law, but whether US patents had to be consistent with laws of physics was a subject of discussion in previous EM Drive threads).
I also very much doubt that the US Patent Office has a working model of this device (I was told by US Patent Lawyers that the US Patent office run out of room a long time ago to store such models, even for devices claiming to go overunity).
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#1612
by
rfmwguy
on 11 Jan, 2016 16:21
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..
I did have one observation on the magnetron modification experiments with a few small neodymium magnets placed against the ring magnets...once heated over 100 degrees C, the small magnets lost much of their strength.
It returned once they cooled to room temp. How did I notice this? When I moved the magnets around the ring magnet, it was FAR easier to do when they were hot.
Back EMF is probably highly dependent on temperature. I did not see any thermal testing of this guys assembly.
The case is also interesting because we have the US Patent Office still awarding (just last week) a US patent for an invention claiming "zero power factor for purely resistive load" (and separately to the press claiming 7000% efficiency).
Showing that getting a US patent does not mean that the invention has to be explained by the laws of Physics (nothing new to those familiar with US patent law, but whether US patents had to be consistent with laws of physics was a subject of discussion in previous EM Drive threads).
I also very much doubt that the US Patent Office has a working model of this device (I was told by a Patent Lawyer that the US Patent office run out of room a long time ago to store such models).
Understand, my gr-gr-grandfather had a patent for an improved buggy jack. LOL! It never amounted to anything except for his name on the patent.
Speaking of patents, where did Voith (your old company) come up with a name like emdrive? Was this an extension of one of their naming conventions, therefore a coincidence? Its not a common name for anything best I can tell...well except for Emerson's guitar accessory.
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#1613
by
Rodal
on 11 Jan, 2016 16:25
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...
Understand, my gr-gr-grandfather had a patent for an improved buggy jack. LOL! It never amounted to anything except for his name on the patent.
Speaking of patents, where did Voith (your old company) come up with a name like emdrive? Was this an extension of one of their naming conventions, therefore a coincidence? Its not a common name for anything best I can tell...well except for Emerson's guitar accessory.
Germans nowadays like to adopt English names for marketing and export (to foreign countries) reasons, and EMDrive can be short for "ElectroMagnetic Drive" or "ElectroMechanical Drive" which is what the device trademarked by Voith is. It is a an electromagnetic/mechanical drive (it has mechanical components since it is a Motor-Gear-Unit) for urban rail.
(An old-fashioned electromagnetic drive, not a radio-frequency thruster at all
).
From this example we can see that Wikipedia, may have been quite wise in changing the name of the EM Drive wiki article to <<RF resonant cavity thruster>> which in retrospect seems much more appropriate than "EMDrive" given the common connotation of "drive" and the fact that the "M" may stand for "mechanical" as well as "magnetic".
Putting my marketing hat on,
"EM thruster" or "EM rocket" would be better than "EM drive" as drive means many old-fashioned things unrelated to anything new.
The "wisdom of the masses" that contributes to Wikipedia
PS: It would have cost Roger Shawyer only 250 Euros to trademark "EMDrive" in Europe (which is now trademarked in Europe and in the USA by two different companies, for completely routine products).
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#1614
by
SteveD
on 11 Jan, 2016 17:08
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I've always found this over-unity motor stuff interesting...but that's about it.
I did have one observation on the magnetron modification experiments with a few small neodymium magnets placed against the ring magnets...once heated over 100 degrees C, the small magnets lost much of their strength.
It returned once they cooled to room temp. How did I notice this? When I moved the magnets around the ring magnet, it was FAR easier to do when they were hot.
Back EMF is probably highly dependent on temperature. I did not see any thermal testing of this guys assembly.
I can't help but wonder if this is an expiramental demonstration of that negative mass conjecture I've been going on about. Seems like the same problem cited with the EMDrive, a flywheel being accelerated over unity. If the answer were that the mass of the flywheel decreases when it goes, apparently, over unity then you might not have any more energy out than you put in. Would help explain why these things keep getting invented, and disproven. Measuring the RPM tells you that you have an over unity, when you measure the energy out the over unity disappears.
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#1615
by
rfmwguy
on 11 Jan, 2016 17:28
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I've always found this over-unity motor stuff interesting...but that's about it.
I did have one observation on the magnetron modification experiments with a few small neodymium magnets placed against the ring magnets...once heated over 100 degrees C, the small magnets lost much of their strength.
It returned once they cooled to room temp. How did I notice this? When I moved the magnets around the ring magnet, it was FAR easier to do when they were hot.
Back EMF is probably highly dependent on temperature. I did not see any thermal testing of this guys assembly.
I can't help but wonder if this is an expiramental demonstration of that negative mass conjecture I've been going on about. Seems like the same problem cited with the EMDrive, a flywheel being accelerated over unity. If the answer were that the mass of the flywheel decreases when it goes, apparently, over unity then you might not have any more energy out than you put in. Would help explain why these things keep getting invented, and disproven. Measuring the RPM tells you that you have an over unity, when you measure the energy out the over unity disappears.
Could be, but one thing for sure, these types of experiments can help us sort out the emdrive by focusing on ALL possible error sources. Mr Li and Doc's paper have done the most to help but we need more before we jump the shark and say its a true mass reduction of one end or the other.
Problem is, photons are a bit of a conundrum in physics best I can tell. Winking into and out of existence, changing from a particle to wave based on measurement method, rest mass of zero yet I've never seen a photon at rest, etc...still enough unanswered questions that I'm staying interested...
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#1616
by
zellerium
on 11 Jan, 2016 18:39
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After much research, I've determined that this is the best way to construct a frustum...seamless at the small diameter:
...
This horizontal lathe was modified to include a spinning "form", or shape, that the copper sheet "folds" over. The left side of the lathe uses a compression disc that snugs the copper sheet onto the top of the form, which could be any shape. A frustum would be one of the more simpler forms to have constructed.
The brass-smith said he could make a bell/frustum but it would have a brazed seam that would have to be ground/polished away. More labor costs.
The cost is similar for both ways to do it. Looks like the spinning copper method is superior. Interior polishing would be needed.
I think the best way to construct a frustum is from a solid slug of aluminum turned down and bored out on a CNC lathe. Wall thickness could be chosen to be 1/2 inch and provide better thermal properties. The inside could be coated with a thin layer of evaporated silver to improve conductivity (this requires a vacuum chamber). The delivery waveguides could be set in the wall a tacked around the edges for added stability and conductivity. The end caps could be made by slicing off the ends of the original slug and a spherical cut could be made on a CNC mill.
I'm not planning to make this anytime soon, but I've put a lot of thought into it.
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#1617
by
Mulletron
on 11 Jan, 2016 19:06
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#1618
by
zen-in
on 11 Jan, 2016 19:58
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After much research, I've determined that this is the best way to construct a frustum...seamless at the small diameter:
...
This horizontal lathe was modified to include a spinning "form", or shape, that the copper sheet "folds" over. The left side of the lathe uses a compression disc that snugs the copper sheet onto the top of the form, which could be any shape. A frustum would be one of the more simpler forms to have constructed.
The brass-smith said he could make a bell/frustum but it would have a brazed seam that would have to be ground/polished away. More labor costs.
The cost is similar for both ways to do it. Looks like the spinning copper method is superior. Interior polishing would be needed.
I agree, metal-spinning would be best method as long 101 alloy (99.9% pure Cu) is used. A machinest may prefer using another alloy for safety or other reasons. Metal spinning is another way of moving metal. Part of the process involves keeping the periphery of the disk from getting too thick and cracking. The inside surface would be reasonably smooth and so would have very good surface conductivity. The outside would show the characteristic rings the turning tool leaves. Polishing the inside wouldn't be too difficult. Just clamp the fustrum to a workbench and have at it with a 6" Dia buffer wheel and some pumice compound for starters. The form is turned from laminated hardwood.
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#1619
by
rfmwguy
on 11 Jan, 2016 20:07
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After much research, I've determined that this is the best way to construct a frustum...seamless at the small diameter:
...
This horizontal lathe was modified to include a spinning "form", or shape, that the copper sheet "folds" over. The left side of the lathe uses a compression disc that snugs the copper sheet onto the top of the form, which could be any shape. A frustum would be one of the more simpler forms to have constructed.
The brass-smith said he could make a bell/frustum but it would have a brazed seam that would have to be ground/polished away. More labor costs.
The cost is similar for both ways to do it. Looks like the spinning copper method is superior. Interior polishing would be needed.
I agree, metal-spinning would be best method as long 101 alloy (99.9% pure Cu) is used. A machinest may prefer using another alloy for safety or other reasons. Metal spinning is another way of moving metal. Part of the process involves keeping the periphery of the disk from getting too thick and cracking. The inside surface would be reasonably smooth and so would have very good surface conductivity. The outside would show the characteristic rings the turning tool leaves. Polishing the inside wouldn't be too difficult. Just clamp the fustrum to a workbench and have at it with a 6" Dia buffer wheel and some pumice compound for starters. The form is turned from laminated hardwood.
Thanks Zen...do you have a gut feel as to what the mil thickness should be?
http://www.onlinemetals.com/merchant.cfm?id=966&step=2&top_cat=87&showunits=mmThanks - Dave
Like the attached "chimney" one for my setup, which I am starting to suspect is very real (and is amplified by the large asymmetrical cavity on the platform).
).