Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1878815 times)

Offline Mulletron

  • Full Member
  • ****
  • Posts: 1116
  • Liked: 779
  • Likes Given: 1030
I really thought Pinheiro's "self accelerating engine" would have stirred the pot more than it did.

Folks are up in arms about how EmDrive violates Conservation of Momentum and Newton's Third Law.

This paper really made me go hmmmmm.

On Newton's third law and its symmetry-breaking effects
Mario J Pinheiro
http://iopscience.iop.org/1402-4896/84/5/055004
http://arxiv.org/pdf/1104.5011.pdf (see page 12, pg 18 fig 2)

@Rodal did a fantastic thermal analysis early on. So we're already smart on this.
http://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECT

So did one end stay hotter than the other while turned on? I bet TE012 would generate tons of heat at the small end (strong magnetic field there). Actual thermal data would be awesome right about now. My dinky amp doesn't generate any noticeable heat and it can't excite TE01X anyway. We miss having you here @Star Drive. I bet you already know all about this.

I did manage to dig up his thermal analysis from here:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326997#msg1326997
and is attached. This looks like it was TM212 @ 1946.65 MHz.



Why am I looking into https://en.wikipedia.org/wiki/Non-equilibrium_thermodynamics ?
It is clear to me that the "momentum from the QV fluctuations" mechanism (if it is even really happening) isn't the dominant mechanism here. For cavities sans dielectrics, this is especially apparent. Shawyer et al report thrust from unloaded cavities (Eagleworks did not).
There must be another...or more than one "thrust mechanism" happening simultaneously here.

Gotta go back through the threads and locate which modes @Star Drive said caused the frustum to thrust large end forward to see if there are any patterns. I remember at least one instance where he reported the dielectric fastener popped loose and the thrust reversed too.

Been taking a break on the research and enjoying the summer (really don't want to get burned out here). Turns out there are other things in life besides EmDrive. Enjoying the family time. Will jump back in full swing with the experiment soon.
Challenge your preconceptions, or they will challenge you. - Velik

Offline TheTraveller

Further info on the antenna arrangement I'll be using on my 2.45GHz version of the Flight Thruster.

As the EM waves in a cavity with spherical end plates are spherical, the antenna also needs to be spherical as per the sidewall insertion point curve of the EM wave at that point.

I could have used a single stub 1/4 wave antenna curved to match the spherical EM wave shape but I had reservations that the end point of a single 1/4 wave stub inside the cavity may shift over time.

To stop any shifting, especially as I plan to ship finished EMDrives all over the planet, the single 1/4 wave stub antenna was replaced by 3 x 1/4 wave stub antennas that are joined at the centre and attached to the centre of 3 Rf connectors fitted into the side walls.

Trust the attached crude drawing makes it clear how I intend to excite TE013 mode and do so in a way to introduce min phase distortion into the internal resonant standing wave by the excitation antenna.
I would hope you take in consideration the phases of your antennas and the distance from each other, you wouldn't want them to cause standing wave attenuations with each other canceling out a good idea.

Shell, there is also the issue that in the drawing, the assumption is made that the wave-patterns in the longitudinal direction are sinusoidal harmonic with equidistant nodal points.  This is true for a cylindrical waveguide but it is not true for a conical waveguide.  With a conical waveguide the wave-patterns in the longitudinal direction are not sinusoidal harmonic: the nodes are not equidistant.  How different from equidistant the nodes are depends on the mode(s) being excited and their participation. Hopefully by placing the antenna where it is proposed he can force that mode, but a lot depends on nearby modes and mode participation.  Since he is not using a magnetron, that may help in eliminating other modes from participating.

I'm quite aware the nodes are not equidistant as the guide wavelength varies as the tapered waveguide diameter varies along the tapered waveguide.

My calculator figures out where the 1/4 wave position is from the big end, factoring in the continually variable guide wavelength and the radius of curvature of the spherical wave at that point.

There are no nearby TE modes and my antenna will not excite TM modes.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline TheTraveller

I really thought Pinheiro's "self accelerating engine" would have stirred the pot more than it did.

Folks are up in arms about how EmDrive violates Conservation of Momentum and Newton's Third Law.

This paper really made me go hmmmmm.

On Newton's third law and its symmetry-breaking effects
Mario J Pinheiro
http://iopscience.iop.org/1402-4896/84/5/055004
http://arxiv.org/pdf/1104.5011.pdf (see page 12, pg 18 fig 2)

@Rodal did a fantastic thermal analysis early on. So we're already smart on this.
http://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECT

So did one end stay hotter than the other while turned on? I bet TE012 would generate tons of heat at the small end (strong magnetic field there). Actual thermal data would be awesome right about now. My dinky amp doesn't generate any noticeable heat and it can't excite TE01X anyway. We miss having you here @Star Drive. I bet you already know all about this.

I did manage to dig up his thermal analysis from here:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326997#msg1326997
and is attached. This looks like it was TM212 @ 1946.65 MHz.



Why am I looking into https://en.wikipedia.org/wiki/Non-equilibrium_thermodynamics ?
It is clear to me that the "momentum from the QV fluctuations" mechanism (if it is even really happening) isn't the dominant mechanism here. For cavities sans dielectrics, this is especially apparent. Shawyer et al report thrust from unloaded cavities (Eagleworks did not).
There must be another...or more than one "thrust mechanism" happening simultaneously here.

Gotta go back through the threads and locate which modes @Star Drive said caused the frustum to thrust large end forward to see if there are any patterns. I remember at least one instance where he reported the dielectric fastener popped loose and the thrust reversed too.

Been taking a break on the research and enjoying the summer (really don't want to get burned out here). Turns out there are other things in life besides EmDrive. Enjoying the family time. Will jump back in full swing with the experiment soon.

Go here.
https://drive.google.com/folderview?id=0B7kgKijo-p0ifk9EakZfbW9aZGMwNWZMQ01xVnBON0tkM2w0Q1NLbmtjRFFwMXBuNVlVN0U&usp=sharing

Open the PaulMarch folder. Has every attached image and doc that Paul shared on NSF.
« Last Edit: 07/09/2015 02:11 PM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline Rodal

  • Senior Member
  • *****
  • Posts: 5895
  • USA
  • Liked: 6045
  • Likes Given: 5325
I really thought Pinheiro's "self accelerating engine" would have stirred the pot more than it did.

Folks are up in arms about how EmDrive violates Conservation of Momentum and Newton's Third Law.

This paper really made me go hmmmmm.

On Newton's third law and its symmetry-breaking effects
Mario J Pinheiro
http://iopscience.iop.org/1402-4896/84/5/055004
http://arxiv.org/pdf/1104.5011.pdf (see page 12, pg 18 fig 2)

...

Very good point !

The lack of an immediate response is a combination of things. There are so many things to analyze that we get overwhelmed.  Since we have day jobs, we address either what we are best at or what we find most interesting at the moment.  Some of us concentrate on experimental builds, others concentrate on closed-form solutions to simplifications that are amenable to a mathematical solution, and others concentrate on numerical analysis.  Also, non-equilibrium thermodynamics of a photon gas is complicated.

To get to the point, concerning <<. The new approach presented here shows that Newton's third law is not verified in systems out of equilibrium due to an additional entropic gradient term present in the particle's momentum>>, I think that Dr. Notsosureofit was looking at this from the non-stationary thermodynamics point of view, but he has a small R&D company to run and many other pressing things to do.  We do get small updates every once in a while. 

One interesting thing I looked at in this respect is that a photon gas does not have the number N of photons as a thermodynamic constant but photons can be "created" and "anhilitated" all the time, and the number of photons in a photon gas is a very nonlinear function of temperature (the cube of the temperature): (N number of photons)



That is very different from a perfect molecular gas where (N number of moles)



Showing that at constant pressure and volume, the number of moles is inversely proportional to the temperature.

Quote
A very important difference between a gas of massive particles and a photon gas with a black body distribution is that the number of photons in the system is not conserved. A photon may collide with an electron in the wall, exciting it to a higher energy state, removing a photon from the photon gas. This electron may drop back to its lower level in a series of steps, each one of which releases an individual photon back into the photon gas. Although the sum of the energies of the emitted photons are the same as the absorbed photon, the number of emitted photons will vary. It can be shown that, as a result of this lack of constraint on the number of photons in the system, the chemical potential of the photons must be zero for black body radiation. 
« Last Edit: 07/09/2015 02:57 PM by Rodal »

Offline Notsosureofit

  • Full Member
  • ****
  • Posts: 656
  • Liked: 704
  • Likes Given: 1367
I really thought Pinheiro's "self accelerating engine" would have stirred the pot more than it did.

Folks are up in arms about how EmDrive violates Conservation of Momentum and Newton's Third Law.

This paper really made me go hmmmmm.

On Newton's third law and its symmetry-breaking effects
Mario J Pinheiro
http://iopscience.iop.org/1402-4896/84/5/055004
http://arxiv.org/pdf/1104.5011.pdf (see page 12, pg 18 fig 2)


Yes.  Slow going w/ very limited time...but from Einstein working forward in terms of limited delta f instead of "black body" radiation, the thermodynamics would seem to be there.  So far, I'm still of the opinion that (the Turtle is correct) it's the resonant standing wave condition that supplies the force through a General Relativistic rotation in the time-z plane.

Edit:  I should add that finding the 90 degree phase shift component in that rotation is essential to this argument.
« Last Edit: 07/09/2015 02:34 PM by Notsosureofit »

Online SeeShells

  • Senior Member
  • *****
  • Posts: 2335
  • Every action there's a reaction we try to grasp.
  • United States
  • Liked: 2982
  • Likes Given: 2601
I really thought Pinheiro's "self accelerating engine" would have stirred the pot more than it did.

Folks are up in arms about how EmDrive violates Conservation of Momentum and Newton's Third Law.
Been taking a break on the research and enjoying the summer (really don't want to get burned out here). Turns out there are other things in life besides EmDrive. Enjoying the family time. Will jump back in full swing with the experiment soon.

Welcome back you were missed. Look forward to you being back.

Shell

Offline Ricvil

  • Member
  • Posts: 69
  • Liked: 66
  • Likes Given: 24
The cavity is reservatory of energy, like a LC circuit. If a mode has been excited by the source is natural the growing of amplitude of the fields because of the succesives reflections of the counter propagating traveling waves ( forming the stationary wave) will summ with waves generated by the source. This grow will happens until the loss  in the walls of the cavity becomes equal the power generated by the source.

Offline Rodal

  • Senior Member
  • *****
  • Posts: 5895
  • USA
  • Liked: 6045
  • Likes Given: 5325
The cavity is reservatory of energy, like a LC circuit. If a mode has been excited by the source is natural the growing of amplitude of the fields because of the succesives reflections of the counter propagating traveling waves ( forming the stationary wave) will summ with waves generated by the source. This grow will happens until the loss  in the walls of the cavity becomes equal the power generated by the source.

Thank you.  I fully agree.  Using the SI unit conversions one can see that the Meep analysis is looking at an extremely early time in the time evolution of these fields.

Offline rfmwguy

  • EmDrive Builder (retired)
  • Senior Member
  • *****
  • Posts: 2165
  • Liked: 2681
  • Likes Given: 1124
Advanced data analysis -  For DIYers, I'd recommend we consider standardizing on some DAC software. I've written a couple of LabView projects which are basically a clean slate in displaying test data. (have no biz relationship with National Instruments BTW, just good results).

http://www.ni.com/labview/

There are student discounts and a free trial period. Chart recordings, temperatures, displacement, vibration, acceleration, voltages, currents, etc are all possible with external sensors. I have this in the back of my mind if I see positive results from the fulcrum test.

Word of note, shielding of all sensor interconnects will be critical and I wouldn't start off with this initially. Non-digital measurement is less risky of false positives, but those planning on more elaborating testing down the road should consider LabView as an easy to use GUI based test platform.

http://sine.ni.com/cms/images/casestudies/bmpc.bmp?size


Offline DrBagelBites

  • Member
  • Posts: 71
  • Orlando
  • Liked: 59
  • Likes Given: 68
Advanced data analysis -  For DIYers, I'd recommend we consider standardizing on some DAC software. I've written a couple of LabView projects which are basically a clean slate in displaying test data. (have no biz relationship with National Instruments BTW, just good results).

http://www.ni.com/labview/

There are student discounts and a free trial period. Chart recordings, temperatures, displacement, vibration, acceleration, voltages, currents, etc are all possible with external sensors. I have this in the back of my mind if I see positive results from the fulcrum test.

Word of note, shielding of all sensor interconnects will be critical and I wouldn't start off with this initially. Non-digital measurement is less risky of false positives, but those planning on more elaborating testing down the road should consider LabView as an easy to use GUI based test platform.

http://sine.ni.com/cms/images/casestudies/bmpc.bmp?size

Already downloaded. :) Using it in conjunction with an oscilloscope to check and make sure the signal generator is outputting the correct values.

The DAQs are quite expensive, at least for me anyways. So, I'll hold off on data acquisition in that respect. But Free/19.99 for student edition is a lot better than $10,000 for the full program.

Edit: once I finish the OpenCV program, I'll post it here in case others want to use this method for data acquisition on a laser. My goal is to be accurate to within a millimeter. Maybe less.
« Last Edit: 07/09/2015 03:19 PM by DrBagelBites »

Offline Rodal

  • Senior Member
  • *****
  • Posts: 5895
  • USA
  • Liked: 6045
  • Likes Given: 5325
...So far, I'm still of the opinion that (the Turtle is correct) it's the resonant standing wave condition that supplies the force through a General Relativistic rotation in the time-z plane.

Edit:  I should add that finding the 90 degree phase shift component in that rotation is essential to this argument.
Have you taken a look at Todd's (WarpTech's ) latest analysis?

His formulation looks (at least superficially) similar to yours.  Any comments on a comparison of Notsosureofit and WarpTech's latest would be deeply appreciated, if you have a chance.



http://forum.nasaspaceflight.com/index.php?topic=37642.msg1400288#msg1400288

http://forum.nasaspaceflight.com/index.php?topic=37642.msg1401513#msg1401513
« Last Edit: 07/09/2015 03:33 PM by Rodal »

Online SeeShells

  • Senior Member
  • *****
  • Posts: 2335
  • Every action there's a reaction we try to grasp.
  • United States
  • Liked: 2982
  • Likes Given: 2601
Further info on the antenna arrangement I'll be using on my 2.45GHz version of the Flight Thruster.

As the EM waves in a cavity with spherical end plates are spherical, the antenna also needs to be spherical as per the sidewall insertion point curve of the EM wave at that point.

I could have used a single stub 1/4 wave antenna curved to match the spherical EM wave shape but I had reservations that the end point of a single 1/4 wave stub inside the cavity may shift over time.

To stop any shifting, especially as I plan to ship finished EMDrives all over the planet, the single 1/4 wave stub antenna was replaced by 3 x 1/4 wave stub antennas that are joined at the centre and attached to the centre of 3 Rf connectors fitted into the side walls.

Trust the attached crude drawing makes it clear how I intend to excite TE013 mode and do so in a way to introduce min phase distortion into the internal resonant standing wave by the excitation antenna.
I would hope you take in consideration the phases of your antennas and the distance from each other, you wouldn't want them to cause standing wave attenuations with each other canceling out a good idea.

Shell, there is also the issue that in the drawing, the assumption is made that the wave-patterns in the longitudinal direction are sinusoidal harmonic with equidistant nodal points.  This is true for a cylindrical waveguide but it is not true for a conical waveguide.  With a conical waveguide the wave-patterns in the longitudinal direction are not sinusoidal harmonic: the nodes are not equidistant.  How different from equidistant the nodes are depends on the mode(s) being excited and their participation. Hopefully by placing the antenna where it is proposed he can force that mode, but a lot depends on nearby modes and mode participation.  Since he is not using a magnetron, that may help in eliminating other modes from participating.

I'm quite aware the nodes are not equidistant as the guide wavelength varies as the tapered waveguide diameter varies along the tapered waveguide.

My calculator figures out where the 1/4 wave position is from the big end, factoring in the continually variable guide wavelength and the radius of curvature of the spherical wave at that point.

There are no nearby TE modes and my antenna will not excite TM modes.

It will be tight positioning the 3 antennas in that mode looking at the poynting vectors. I'm not saying it can't be done I'm just curious.

Shell


Offline rfmwguy

  • EmDrive Builder (retired)
  • Senior Member
  • *****
  • Posts: 2165
  • Liked: 2681
  • Likes Given: 1124
Advanced data analysis -  For DIYers, I'd recommend we consider standardizing on some DAC software. I've written a couple of LabView projects which are basically a clean slate in displaying test data. (have no biz relationship with National Instruments BTW, just good results).

http://www.ni.com/labview/

There are student discounts and a free trial period. Chart recordings, temperatures, displacement, vibration, acceleration, voltages, currents, etc are all possible with external sensors. I have this in the back of my mind if I see positive results from the fulcrum test.

Word of note, shielding of all sensor interconnects will be critical and I wouldn't start off with this initially. Non-digital measurement is less risky of false positives, but those planning on more elaborating testing down the road should consider LabView as an easy to use GUI based test platform.

http://sine.ni.com/cms/images/casestudies/bmpc.bmp?size

Already downloaded. :) Using it in conjunction with an oscilloscope to check and make sure the signal generator is outputting the correct values.

The DAQs are quite expensive, at least for me anyways. So, I'll hold off on data acquisition in that respect. But Free/19.99 for student edition is a lot better than $10,000 for the full program.

Edit: once I finish the OpenCV program, I'll post it here in case others want to use this method for data acquisition on a laser. My goal is to be accurate to within a millimeter. Maybe less.
Nice, here is the company I used several years ago for inexpensive DAQ stuff: http://www.dataq.com

Edit: DAC/ADC/DAQ...whatever, I get confused at my age ;)
« Last Edit: 07/09/2015 03:46 PM by rfmwguy »

Offline Notsosureofit

  • Full Member
  • ****
  • Posts: 656
  • Liked: 704
  • Likes Given: 1367
...So far, I'm still of the opinion that (the Turtle is correct) it's the resonant standing wave condition that supplies the force through a General Relativistic rotation in the time-z plane.

Edit:  I should add that finding the 90 degree phase shift component in that rotation is essential to this argument.
Have you taken a look at Todd's (WarpTech's ) latest analysis?

His formulation looks (at least superficially) similar to yours.  Any comments on a comparison of Notsosureofit and WarpTech's latest would be deeply appreciated, if you have a chance.


see: http://www.ece.rutgers.edu/~orfanidi/ewa/ch09.pdf

Not really, time is very short.

Online SeeShells

  • Senior Member
  • *****
  • Posts: 2335
  • Every action there's a reaction we try to grasp.
  • United States
  • Liked: 2982
  • Likes Given: 2601
I really don't like this, to ask. I've always forged my own path through the years with very little help and built businesses in industries where a billion spent is sometimes a drop in the bucket.

Totaling up what the costs I'm facing it became clear that with the little I get on retirement I can't do it in the time frame needed. I guess I'm asking for a little help and only if you can.

I'm so driven to see real data from these test and to add to the pool of knowledge, I have to swallow my pride and ask.

http://www.gofundme.com/yy7yz3k

Thank you all for your support, your ideas and most of all sharing a dream.

Shell

Offline BL

  • Member
  • Posts: 17
  • Liked: 30
  • Likes Given: 0
Re frobnicat Post #3681

“But you seem to imply in your posts that the risk is more in false negatives (a working principle and experimenters failing to record thrust from it) rather than false positives (a bogus principle and experimenters failing to report null results, down to a certain sensitivity).”

You are right.  Sorta.  What I am saying is that the risk is BOTH.

We are trying to determine:
a.  Is the EmDrive effect real?
b.  Or not?

Assume a.  A closed frustum will, as advertised by Shawyer et al, produce thrust when excited by a microwave source at one or more of its resonant frequencies.  The thrust is proportional to the Q of the frustum and the power applied.

Assume b.  A frustum excited by microwaves cannot produce thrust.  Previous positive results were artifacts of the test procedures.

The free-running magnetron whose spec sheet says it produces 1 kw @ 2.45 GHz is connected to the frustum that was sized to resonate at 2.45 GHz and is turned on.  Thrust ensues.  Turned off; thrust disappears.  Frustum reversed.  Turn on, thrust in the opposite direction, same magnitude.  Turn off; no thrust.  Victory is ours.  Maybe, after we examine the test rig and test procedures to ensure that the thrust was produced by the frustum instead of the test apparatus. 

Same procedure.  No thrust.  Now what?

The typical DIY-er using a $20 magnetron probably doesn’t have a Vector Network Analyzer lying around his garage to sweep the frustum, locate the multiple resonant frequencies and plot their response. 

He (or, in the case of SeeShells, she) probably doesn’t have access to a microwave spectrum analyzer to examine the output spectrum of the magnetron, while it is connected to the frustum, and determine if it is producing energy at one or more of the unknown (to him) resonant frequencies of the frustum, or determine how much of the total magnetron output power falls within the bandwidth of the mode in question.  Is the resonant mode important?  Each frustum has multiple modes of resonance.  If the magnetron is producing energy at only ONE of the resonant frequencies, do we have case a or case b? How does the DIY’er determine if he is even TESTING case a?

Go down the decision tree.  The only case in which we have learned something is when thrust is always produced (Yay!).  That provides ‘proof of principle’, which in this case is what we are all hoping for.

If NO thrust is detected:

Principle not valid?
Wrong mode excited?
Little or no energy at the frequency of resonance?
Low Q at the frequency applied?

SeeShells, and most everyone else, says that we need data.  I wholeheartedly agree.  My opinion is that except in the single instance in which measurable thrust is produced every time the magnetron is turned on, DIY frustums driven by oven magnetrons don’t provide any.  Absent unambiguous, repeatable thrust when the magnetron is energized, DIY free running magnetron driven frustums cannot even HELP us decide between case a and case b.

An example.   A frustum is built.  It has a Q of (picking a plausible number) 10,000 (bandwidth of ~250 kHz).  The magnetron is connected and energized.  It has an output spectrum 30+ MHz wide, with power distributed among a LOT of spectral lines, with nothing much in between them.  Thrust happens, but tapers off after a few seconds.  Test transient?  Spectral line at ‘good’ freq on power up, but as the frustum/magnetron heats the spectral line moves off the ‘good freq’?  Walls heat, changing resistivity and, as a consequence, lowering Q?  Case a or case b?  No immediate thrust, but gradual increase in thrust as test continues.  Heating frustum/magnetron causes response peak to move over a spectral line or hot air?  Case a or case b?  No thrust at all.  Any energy within the bandwidth of the frustum?  Energy within frustum bandwidth, but wrong mode for producing thrust?  Case a or case b?  If you can’t control your source and match it to the response characteristics of the frustum, you can’t decide.  The only situation ‘decidable’ with a free running magnetron is if the phenomenon is real and relatively insensitive to drive characteristics. 

The claim by Shawyer and others that thrust occurs and is proportional to Q and power is not falsifiable with a free running magnetron and it is confirmable only with the help of a LOT of luck.  The more mods that are applied to the magnetron/frustum to enable the test to be controlled, the closer the whole shebang comes to a synthesized sig gen, driving a broad band power amplifier, feeding a frustum whose response has been carefully measured with a VNA.

Offline WarpTech

  • Full Member
  • ****
  • Posts: 1313
  • Do it!
  • Vista, CA
  • Liked: 1351
  • Likes Given: 1817
...
The paradox with propellant driven space craft was explained too, by Dr. White. It occurs anytime "constant acceleration" is assumed, without taking into account the variables in the av(t) expression I posted. In the case of the EM drive where there is no exhaust, dm/dt is replaced by the change in potential energy from the small end, to the big end, per unit time, /c2.

And BTW, if the EM drive were to store every bit of energy put into it, with a high power source it would have to explode eventually. The energy either needs to escape, generate heat or move the thing in order to dissipate. Or else the source input will eventually become saturated until nothing more will go in.
Todd
Each time I try to stay on topic with this breakeven business, which you say I have "wrong", you throw another spanner in the works. Let's try and focus here. I want to understand what's "wrong" as you see it. So far, you're not making sense to me. If you do want to make sense to me, and convince me that I'm "wrong", you're going to have to take my derivation and show, line by line, the "right" substitution.

Over to you.

Here is how it's done, starting from your format to mine. The difference in potential energy is from the initial energy state at the small end, to the final energy state at the big end.
Todd
« Last Edit: 07/09/2015 04:26 PM by WarpTech »

Online SeeShells

  • Senior Member
  • *****
  • Posts: 2335
  • Every action there's a reaction we try to grasp.
  • United States
  • Liked: 2982
  • Likes Given: 2601
Re frobnicat Post #3681

“But you seem to imply in your posts that the risk is more in false negatives (a working principle and experimenters failing to record thrust from it) rather than false positives (a bogus principle and experimenters failing to report null results, down to a certain sensitivity).”

You are right.  Sorta.  What I am saying is that the risk is BOTH.


*** That is understood from the start, with great risk comes great reward and great failure.  It is what it is, all I want to do is find out what is happening. I use the dream of what might be to drive me, not to jade my outlook at the data may show. Like I said before... there is no bad data.

I would love to have my old lab back, but I don't. I would love to have the equipment to test this thing upside down and inside out but I don't, so I will take the first small step the step that I can and use the data I get to take the next.

I've built machinery that went into cleans rooms in some of the best known names in the industry and the testing was to the extreme. I have no disillusions about what needs to be done, I'm just working with what I have.

Us DYiers or if you want "Crazy Eddies" are doing what industry should with what little we have. Sadly industry has changed over the years and research dollars have been stingy and budgets cut.

You're not pointing out what most of us already know and wished was different.

Shell

Offline VAXHeadroom

  • Full Member
  • *
  • Posts: 196
  • Whereever you go, there you are. -- BB
  • Baltimore MD
  • Liked: 259
  • Likes Given: 151
I really don't like this, to ask. I've always forged my own path through the years with very little help and built businesses in industries where a billion spent is sometimes a drop in the bucket.

Totaling up what the costs I'm facing it became clear that with the little I get on retirement I can't do it in the time frame needed. I guess I'm asking for a little help and only if you can.

I'm so driven to see real data from these test and to add to the pool of knowledge, I have to swallow my pride and ask.

http://www.gofundme.com/yy7yz3k

Thank you all for your support, your ideas and most of all sharing a dream.

Shell

Do or do not.  There is no try. :)
Putting my money where my mouth is, at least a little.
Emory Stagmer
  Executive Producer, Public Speaker UnTied Music - www.untiedmusic.com

Online SeeShells

  • Senior Member
  • *****
  • Posts: 2335
  • Every action there's a reaction we try to grasp.
  • United States
  • Liked: 2982
  • Likes Given: 2601
The Chinese may have figured out how to make a cavity with a Q of 117,500 using flat end plates.

As per the attachment they build in a short section, at each end of the tapered wave guide, of constant diameter circular waveguide that allows the spherical waves in the tapered portion of the cavity to transition from/to a planar wave that will generate no phase distortion as it bounces off the flat end plate.

Very clever.

The drawings also show how they do impedance matching.

See attachment.

I now know my 100,000 Q goal is obtainable. Yea!

If you draw a horizontal axis through the middle of the waveguide in the picture you show, what does the waveguide opening into the cavity on the plane perpendicular to that axis look like?



In other words, what does the other view look like?

It would be nice if we could guesstimate what the waveguide opening aspect ratio is, compared to the lateral cavity dimensions

More info is in the paper, which is in Chinese. Attached.

I don't think the drawing is dimensionally correct.

That was very hard to read. there are gems of information within the mix of translations and your right I like the endplates too.

Shell

Tags: