Author Topic: EM Drive Developments - related to space flight applications - Thread 8  (Read 1665470 times)

Offline rfmwguy

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Thus all could change with a new administration coming in. Reports are circulating that Leo and earth science should take a back seat to space exploration.
https://www.yahoo.com/news/trump-administration-set-eliminate-nasa-035716399.html
Dave, what that suggests to me is massive cutbacks to cut costs. It's more about bailing on anything to do with Global Climate Change, than infusing money into exploration. Especially when we see that Elon is willing to put up his own cash to do the Mars shot.

I think you may be right that the private sector is going to be the place to get things done. They are willing to take risks that bureaucracies often shy away from.

Having said that, we all should remember that if it wasn't for John F Kennedy, and a bunch of "steely-eyed-missile-men and women" on the government payroll driving with the best of the aerospace industry, this country would not be the technological powerhouse of engineers and scientists that took knowledge and expertise to the pinnacle the human race has attained.
I agree but today's reality is far more risk adverse imho. Look at those unwilling to entertain anything other than reaction mass research. Fear drives research imo far more than the possibilities of payoff if successful. Reasons are many including tighter budgets yet if research is deemed to be socially responsible, big bucks can flow, I.e. climate research. Trying something risky with a high potential of failure as the moonshot was in JFK's day has been lost. I'm sure interstellar think tanks will continue to collect funds without a charter to produce results other than paperwork, but someone will become zephraim Cochrane, just don't know how many centuries that will take.

Offline ChrisWilson68

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"...From its inception, the EW lab's yearly budget was on a shoe-string and it never exceeded $50k per year for build-material and new test equipment with everything else being bootlegged from NASA surplus storage at JSC after the end of the Space Shuttle program...."
Quite frankly, I'm stunned. $50K out of a budget as big as they have? It feels like they were more interested in being able to say they "have" an advanced research group, then actually doing research.

What Eagle Works is doing is really experimental physics.  That is way outside the charter of JSC.  Heck, it's even way outside the charter of NASA.  JSC is really supposed to be more oriented toward operational aspects of NASA's programs.  Ames and Langley are the more research-oriented NASA centers.  So, it's not really a surprise that JSC can really only find small amounts of money for a group doing basic experimental physics.  None of the money provided to JSC is actually really meant for an experimental physics program.

When the US government wants to spend money on experimental physics, that money normally goes to the Department of Energy, DARPA, the National Science Foundation, etc. -- agencies that are set up to fund basic science research.

I believe you are wrong in the general,intent above. As soon as Prof. Yang published a paper that supported Shawyer's claimed anomalous thrust, it really became an issue of engineering, with an intent on zeroing in on a best or at least near best design, that could produce useable thrust. Which for the purposes of a satellite could be a few newtons or even less of constant thrust.

The science is something that will really come down the road in a case like this, once useable thrust has been confirmed.

The two become intertwined here in these discussions because there is a lot of theoretical speculation that goes on waiting for data from the engineers.

True, once there is a credible accepted theory or the science behind the mechanism, there will be another stage of developement based on the science. Right now for all intents and purposes all there is, is the engineering being teased out by a handful of DIY engineers and institutional investigators.

You don't seem to understand what experimental physics is.

Designing and performing experiments to see if the real world behaves according to theory is what what experimental physics is.  Experimental physics isn't about coming up with explanations for data.  It's about producing the data.

Once the data has been produced, it's up to theoretical physics to come up with explanations for it.

Testing for anomalous force from microwaves is most certainly in the realm of experimental physics.

Engineering is something different.  Engineering is not about coming up with new physical laws or testing to see if physical laws are followed.  Engineering is designing systems based on know physical principles.

Of course, experimental physicists use engineering methods to produce their experimental apparatus, but they are using it toward the goal of experimental physics.  A good example is the LHC at CERN.  It is an enormous engineering project, but in the service of experimental physics.

Offline Bob Woods

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...but someone will become zephraim Cochrane, just don't know how many centuries that will take.


So, get off your butt Zephraim!  ;)  I think it will be sooner rather than later.


Given what has happened in our lives, our grand kids may vacation on Mars when they turn 50. Good tanning; low cancer risk (I hope).

Offline spupeng7

List of unaddressed or missing issues from the recent EW paper via a poster on Reddit.

https://drive.google.com/file/d/0B6juR48k_XoTREUxc1QycWxwZ2M/view

See what you think?

I think the EW paper is the best piece of research on the EmDrive that we have seen to date. Being overly critical of every paragraph is time consuming and slows down progress. It is what it is. Risk taking and not-knowing are what drives the ball forward. IMO, EW did a great job, better than anyone else has done at trying to resolve potential errors.

We have a saying down south, 'doing the hard yards' which is about proving yourself as a worthy worker. The 2016 EW paper is a step on that road but if any of you think that we are even a quarter of the way to proving ourselves, then you are sadly mistaken.

I will gladly bet my life that the emdrive works, but it is my life to spend. If you want the big chunk of tax payer dolla that will keep us ahead of the kind of competition that wont share it with us, then you all must re-double your efforts. EW excluded, they are already pulling their weight.

Go ahead, criticize every word, I wish that I could get some of that negative attention. Dr Rodal is the only one to find a flaw in my work and it has been very helpful indeed. Please everyone, find the flaws because that really is how we make progress.

Optimism equals opportunity.

Offline spupeng7


...
Assuming that B field is the rate of time dynamically changing (increasing or decreasing) and
the E field is a line along which the rate of time is dynamically changing direction (from increasing to decreasing, or vice-versa)...      ...  ;)


Well, I think you have these the wrong way about. 
E field measures depth into dilation, B field measures directional distortion of that dilation due to asymmetry of local charges.   :-)
JMN..

Optimism equals opportunity.

Offline MrFrankenverse

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If I may reference the gun in the box experiment once again, this time using standard recoil and instead annihilating, or removing the final effect of, the bullet.
If provisions are made for a very lightweight elongated box, for example, and standard recoil, it would seem that the container accelerates. Acceleration is imparted to the gun and container immediately and of course prior to being halted by the impact of the projectile.

Offline WarpTech

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...

HFSS spits out all sorts of computed variables and even allows users to input their own equations using any computed variables. Couldnt power dissipated be computed using surface currents on all walls?
Are there any particular equations that I could try to numerically compute?
HFSS is owned by ANSYS (overall, a more powerful program than COMSOL or FEKO).  Do you call it HFSS because you have a version prior to the acquisition by ANSYS or because you are only running the HFSS module?

COMSOL also allows the user to write equations, and so do other programs like ABAQUS, etc.

The problem with using codes like this to calculate a new theory are multifold:

1) These packages are black boxes, and the user does not have complete knowledge of the actual solution algorithms being employed.

2) For a new theory like Todd's one may be unable to actually code a solution because certain variables in the theory are not being computed by the program.  For example I am still surprised that none of the solutions posted by Monomorphic show the quality factor of resonance Q.  Can FEKO calculate the Q? (COMSOL can).  But the Q is easy to calculate compared with other variables that one may need to calculate in a new theory (for example one may need to calculate spatial derivatives of certain functions and these numerical methods are particularly bad concerning accuracy of derivatives.  One may need to satisfy higher order boundary conditions, etc.).

I'm using the newest version of ANSYS  HFSS and have access to some of the other basic modules like structural and fluent for cfd.
I think it can calculate spatial derivatives but I'll have to check. I know Q is a standard output

Maybe something like this could be simulated? This would show thrust and conservation of momentum, per Gauss's Law. I hope I didn't make any typos.


Offline aero

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If I may reference the gun in the box experiment once again, this time using standard recoil and instead annihilating, or removing the final effect of, the bullet.
If provisions are made for a very lightweight elongated box, for example, and standard recoil, it would seem that the container accelerates. Acceleration is imparted to the gun and container immediately and of course prior to being halted by the impact of the projectile.

That's true, unfortunately by looking a little deeper you note that after firing, the momentum of the bullet is equal and opposite the momentum of the container. The center of mass of the container sans bullet does move, and the center of mass of the bullet sans container does move. However, after the bullet strikes the end of the container and stops moving relative to the container,  you will note that the center of mass of the bullet plus container system has not moved.  Yes the ends of the container are displaced but if you were to move the bullet back to the gun, the ends would move back to the starting point. That is because momentum is linear with velocity. If you move the bullet quickly, as in firing it from a gun there is little time for the container to displace, but if you move it back quickly you get the equal and opposite displacement arriving at the starting condition. If you move the bullet back slowly, the container is displaced at a lower velocity over a longer time and once the bullet reaches the gun you again arrive at the starting condition with no displacement of the center of mass of the system.

You can work this out using mv =MV which is the conservation of momentum law with lower case being the bullet and upper case being the container. Plug in values of convenience and use displacement = initial velocity + velocity times time. Use the initial center of mass as the reference point, initial velocity zero, calculate and add up the displacements. The round trip for the bullet will give zero displacement for the container.
Retired, working interesting problems

Offline M.LeBel

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...
Assuming that B field is the rate of time dynamically changing (increasing or decreasing) and
the E field is a line along which the rate of time is dynamically changing direction (from increasing to decreasing, or vice-versa)...      ...  ;)


Well, I think you have these the wrong way about. 
E field measures depth into dilation, B field measures directional distortion of that dilation due to asymmetry of local charges.   :-)
JMN..

Spupeng7: 
This description of E and B comes directly from my model of an EM wave defined as a travelling wave on the variable of the medium, the variable being the rate of the time process. This description follows exactly the rules of induction. We may have come to believe that “Time” was just a convenient metric provided to us freely for us to adorn our graphics... The time process is the actor, not a spectator!

 my edit:  I'm not helping..

« Last Edit: 11/26/2016 11:24 am by M.LeBel »

Offline TheTraveller

TT, re cavity fabrication ..... if memory serves no more than 4/100s" margins? yes?   thnx , FL

Rogers advise was the cavity needs to dimensionally built to +-10x full 5x skin depth.

For copper at 2.45GHz that is +-66um as attached.

Plus the surface needs to be polished to optical requirements and have NO SCRATCHES as any scratches may inhibit proper eddy current formation and thus create distorted internal energy distribution.
It Is Time For The EmDrive To Come Out Of The Shadows

Offline WarpTech

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TT, re cavity fabrication ..... if memory serves no more than 4/100s" margins? yes?   thnx , FL

Rogers advise was the cavity needs to dimensionally built to +-10x full 5x skin depth.

For copper at 2.45GHz that is +-66um as attached.

Plus the surface needs to be polished to optical requirements and have NO SCRATCHES as any scratches may inhibit proper eddy current formation and thus create distorted internal energy distribution.

Or take a short cut.

https://www.amazon.com/gp/product/B00VPYCZFI/ref=od_aui_detailpages00?ie=UTF8&psc=1

;)

Offline SeeShells

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...
Assuming that B field is the rate of time dynamically changing (increasing or decreasing) and
the E field is a line along which the rate of time is dynamically changing direction (from increasing to decreasing, or vice-versa)...      ...  ;)


Well, I think you have these the wrong way about. 
E field measures depth into dilation, B field measures directional distortion of that dilation due to asymmetry of local charges.   :-)
JMN..

Spupeng7: 
This description of E and B comes directly from my model of an EM wave defined as a travelling wave on the variable of the medium, the variable being the rate of the time process. This description follows exactly the rules of induction. We may have come to believe that “Time” was just a convenient metric provided to us freely for us to adorn our graphics... The time process is the actor, not a spectator!

SeeShell: Why the funding problem...? (O.K Mods; stand down!) C’mon! Are we really that naive? Is this here the “don’t think, shut up and calculate” motto? I have watched the starry sky many nights with a Smith & Wesson Star Tron night scope. I have witnessed “those guys” zipping across the sky, form horizon to horizon, in 5 seconds flat! .... and maneuver a few more weird trajectories...(If I know,... others know re: funding) Down here we are inching our way to micro-newtons ... We are not playing in the right field! (pun)

IMO we have to bring the experiment to the very edge of our Planck universe ... where neutrinos live and our physics changes.  ....  blanked out....  only way they could do what they did is by moving everything to the edge of our Planck universe; either h + x or h – x.
M.LeBel,

I hope I'm playing in the right field, working very hard to get at least somewhere. As far as what you have seen in things zipping around the night sky with your Smith & Wesson Star Tron night scope, could be their funding is better than mine, or they have bigger brains.  :o



Best,
Shell

Offline TheTraveller

Simple question to the Forum

If you theory guys had a working EmDrive, on a rotary test rig, at your disposal, what would be the process to develop an acceptable theory to explain what you are observing?

What data would you need from the test rig?

Please try to be specific so I can ensure that data is available.

TT, specific to the test apparatus part of the question. 
First, I would ensure that the air bearing had clean dry air supplied to it.  You would definitely need an oil separator if you were not using an oiless compressor.  You would follow up the output with a 50 foot length of copper tubing coiled inside a tub of water at room temperature.  This is for heat exchanging purposes to ensure the heat of compression was partly eliminated.  Lastly, I would follow with two air regulators.  The first being an inexpensive one to filter out pressure changes as the compressor cycles on and off.  The second being an expensive precision regulator to hold to a fraction of a psi.  If you are using bottled nitrogen I would still use the heat exchanger to compensate for the cooling from expansion.

The air bearing would be placed on a purpose built three legged mounting stand (no cobbled 80/20 or optical breadboard components for this part).  This would all rest on a concrete floor of reasonable thickness and good soil underlayment.  If using a flat bearing combined with a cylindrical bearing, the top of the air bearing would need to be flat enough to support leveling to 0.0005”/ft and that is also the target value for the final level.  Walking around on the concrete floor while leveling should not affect the bubble’s position. If using a hemisphere. You would want to maintain level but not as stringent.  For the hemisphere, maintaining the vertical CG below the spherical center is required.  For either bearing keeping the horizontal CG coincident with the axis of rotation is strongly advised.

The room would be temperature controlled and free of drafts.  A way to shut the HVAC off during tests is important.  A waiting period for the HVAC convection to settle is advised.

A 30 frame per second camera mounted directly above and looking straight down on the experiment is wholly necessary.  30 fps has been proven fast enough for this kind of work although a CCD is preferred over a CMOS sensor that has a rolling shutter.  A rolling shutter would be useless.  Camera and video capture system must not lose its time base by dropping frames as this would corrupt the calculations.  Having angular markings every 10 degree around the bearing and a stationary pointer would allow us to measure position often enough to be useful.  Three full rotations during a testing run is the minimum for good analysis.  Less than one rotation appropriately brings on questions as to the test's validity; in fact, it negates the apparent validity in my mind.  A full rotation would help us evaluate/eliminate level vs. CG errors, interaction with Earth’s magnetic field, and other experimental problems.  Several rotations lets us see if we’ve reached a terminal angular velocity where thrust torque matches profile drag.

A reasonable estimate of the mass moment of inertia of the entire rotating section would allow us to calculate torque and thus force.  I can help with this estimate when the time comes.  As for data, the angular position verses time stamp, and MOI is all that is needed to do the major math.  A side view FLIR, other cameras, room temperature might be useful to analyze if things got weird.

However, before running actual tests we would want to characterize the system with the camera running.  First, with just the bare bearing (nothing mounted) we would want to measure both motoring (Paul called it swirl) torque and coulomb friction.  These let us know that you have a good bearing or need to compensate.  Basically, from stopped, the bearing is allowed to accelerate on its own; it might take hours.  It will accelerate if it is not a perfect bearing and if motoring torque is greater than coulomb friction.  The second test of the still bare bearing would feature you inducing a CW spin by hand and letting it decay on its own, then repeating this CCW.  This might take 10 minutes to an hour for data in each direction.  From this we can confirm the motoring and calculate coulomb.  I have done this for twenty air bearings when required by our customers.  I will scrub a spreadsheet and make it and myself available when the time comes.  Finally, with the full apparatus mounted, we would repeat the hand induced CW and CCW spins and process in the same spreadsheet to get the profile drag components, coulomb, viscous, and turbulence of the all-up experiment.

I have used all these techniques before so none are new to me.  What you require (including MOI and CG) knowledge and control are all part of what we have done for customers and for building our own corporate knowledgebase.  www.space-electronics.com  Count me as someone who wants dearly to see this work while maintaining a healthy skepticism; mainly because I see experiments that simply have not measured up.  That said I am more than willing to help where I can.

Will be using a magnetic thrust bearing.

External sensor will pulse count evenly spaced optical marks around the circumference of the rotary table so that pulse to pulse velocity can be resolved to better than 100:1 at 60 rpm.

From earlier experiments, I know the EmDrive works when measuring static force generation, small to big, as also measured and reported by NASA and Roger.

What I don't know is

1) direction of the Reaction accelerative force vs what will be measured with a static scale based test rig

2) value of the accelerative force vs what will be measure in a static scale based test rig

3) now acceleration alters or not the cavity Q

4) how acceleration and KE gain alters or not the load that the Li Ion batteries see

I have developed a method to directly measure Q from the rise time of the forward power pulse. This gives the ability to measure and record cavity Q on each and every pulse of Rf energy that fills the cavity. It is because of this technique that allows non accelerative and accelerative Q to be measured. Using other Q measurement techniques that require the freq to be varied, would not be able to do this dynamic Q measurement, which I see as at the heart of the experiment.
It Is Time For The EmDrive To Come Out Of The Shadows

Offline TheTraveller

Perhaps L-3 became aware of the potential fire hazard of igniting a plasma in a high Q cavity with high power microwaves? IIRC, ~100 MW is the max for an outstanding vacuum in accelerator cavities. If the Q is 10K, and you put 10KW in, there's your 100 MW.

This is a problem that has to be overcome regardless no? What solution would you recommend? Argon environment? Seems like we have to work this out if this unit is to, quite literally, fly.

According to: https://en.wikipedia.org/wiki/Dielectric_gas SF6 can get you 3 - 6 times 30kv/cm breakdown for air, and freon up to 17, pressurized.

From another article I read somewhere, microwave fields can be near double DC or lower frequency fields, because charges don't have time to accelerate.

We need to have someone give us the impedance/fields in the frustrum to know where arcing is likely, and the most power that it can be expected to handle.

From articles I glanced at a couple weeks ago after TT spoke as though he was thinking superconducting cavities with Q's > 10^7 could handle a kilowatt input (dissipated), I saw (IIRC) 100 - 500 MW peak power (not dissipated, stored energy) in hard vacuum. Do a web search for "superconducting cavity accelerator "breakdown voltage"".

New technology will apparently need to be developed to handle high field strengths.

I just wanted to point out, that some engineer at L-3 may have had their manager snicker at them when they asked about putting 100KW into a cavity with Q > 1000. I don't know. There are limits.

The plan is to pump 35W Rf into the YBCO version of the Flight Thruster.
It Is Time For The EmDrive To Come Out Of The Shadows

Offline OnlyMe

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"...From its inception, the EW lab's yearly budget was on a shoe-string and it never exceeded $50k per year for build-material and new test equipment with everything else being bootlegged from NASA surplus storage at JSC after the end of the Space Shuttle program...."
Quite frankly, I'm stunned. $50K out of a budget as big as they have? It feels like they were more interested in being able to say they "have" an advanced research group, then actually doing research.

What Eagle Works is doing is really experimental physics.  That is way outside the charter of JSC.  Heck, it's even way outside the charter of NASA.  JSC is really supposed to be more oriented toward operational aspects of NASA's programs.  Ames and Langley are the more research-oriented NASA centers.  So, it's not really a surprise that JSC can really only find small amounts of money for a group doing basic experimental physics.  None of the money provided to JSC is actually really meant for an experimental physics program.

When the US government wants to spend money on experimental physics, that money normally goes to the Department of Energy, DARPA, the National Science Foundation, etc. -- agencies that are set up to fund basic science research.

I believe you are wrong in the general,intent above. As soon as Prof. Yang published a paper that supported Shawyer's claimed anomalous thrust, it really became an issue of engineering, with an intent on zeroing in on a best or at least near best design, that could produce useable thrust. Which for the purposes of a satellite could be a few newtons or even less of constant thrust.

The science is something that will really come down the road in a case like this, once useable thrust has been confirmed.

The two become intertwined here in these discussions because there is a lot of theoretical speculation that goes on waiting for data from the engineers.

True, once there is a credible accepted theory or the science behind the mechanism, there will be another stage of developement based on the science. Right now for all intents and purposes all there is, is the engineering being teased out by a handful of DIY engineers and institutional investigators.

You don't seem to understand what experimental physics is.

Designing and performing experiments to see if the real world behaves according to theory is what what experimental physics is.  Experimental physics isn't about coming up with explanations for data.  It's about producing the data.

Once the data has been produced, it's up to theoretical physics to come up with explanations for it.

Testing for anomalous force from microwaves is most certainly in the realm of experimental physics.

Engineering is something different.  Engineering is not about coming up with new physical laws or testing to see if physical laws are followed.  Engineering is designing systems based on know physical principles.

Of course, experimental physicists use engineering methods to produce their experimental apparatus, but they are using it toward the goal of experimental physics.  A good example is the LHC at CERN.  It is an enormous engineering project, but in the service of experimental physics.

So you believe that Shawyer began with a credible theory of physics and then engineered his EmDrive of today from the physics?

While it is true that experiments are being done all of the time by many working on the EmDrive concept, there is at this time no credible mechanism of physics known that results in force. The experiments are experiments tinkering with the engineering design, in large part as a function of trial and error. All working toward producing a drive that will produce enough thrust that the physics (physical mechanism) that produces the thrust can be explored.

Only for those who believe that Shawyer's theory of operation is correct, does your statement hold true. But only to the extent that Shawyer's theory of the science is a true and accurate description of the underlying mechanism...

Look at the historical series of frustums and power supply designs, from Shawyer, to Yang, to EW and several DIYs, and what you will find is a series of engineering improvements and many just starting from scratch with a rather vague idea, of what went before.

The only solid science or scientific tools employed in the designs right now, the simulation software.., all say there should be no net thrust.., and yet it moves.

There seem to be a couple of theories that may be getting close to both describing what is observed, predicting better designs and suggesting a mechanism of operation. But not quite there yet.

I do know what experimental physics is, and so far the credible physics involved seems to be saying an EmDrive should not produce thrust, and yet again.., it moves.

Unless someone is withholding results with undeniable thrusts, we're still working on engineering a functional drive, that can be examined and tested to determine the scientific mechanism of operation.

Even the progression of Shawyer's various drives look more like a series of engineering improvements than the realization of any credible underlying scientific mechanism of operation.

There is a difference between experiments refining an engineering design and scientific experiments based on an underlying scientific theory/model. The first aims to improve or maybe just prove a functional result like thrust, while the second is both designed to meet the requirements of and prove the accuracy of a theoretical model.

We are all, speculating about theory, but so far.., and again unless someone is holding back.., we are still working our way through engineering designs, with the hope of achieving something new and wonderful.

Offline TheTraveller

All I wanted to do was show that the resonant frequency remains constant, despite the fact that there is dispersion happening in each orthogonal component of the wave. Shawyer's model is based on the dispersion along the z-axis, the "guide wavelength" while @Notsosureofit's model is based on dispersion of the frequency as a whole, which it is assumed behaves like the dispersion of the polar wavefront. I would like to reconcile that the two dispersive forces cancel each other out, leaving ONLY dissipation as the primary component of thrust. :)
Todd,


due to EM-field energy to net force it's quite logical that there should be a dissipation component exists in this regard. Better an energy transfer to the thrust component. Pure dissipation, because of resistive losses is also present in a cylindrical conductive cavity, whats needed is a gradient as you describe in your equations, therefore I am with you at this point. :)

Thanks! In this TE013 mode, we can model it as 3 separate oscillators, all with the same resonant frequency. Based on the wavelengths, the big end would have higher inductance (L), higher resistance (R) and lower capacitance (C). The small end would have lower inductance, lower resistance and higher capacitance. The one in the middle, would be well... in the middle of the range for each component value.

If we use the definition of the decay time as tau ~ L/R. If properly designed there will have 3 different values, hence there is a gradient in the decay time as the energy is dissipated. Charging and discharging should generate a thrust due to this gradient.

I'm just not sure how to determine the momentum of the magnetic flux that is escaping through the voltage drop in the metal.

Using standard microwave engineering equations for guide wavelength vs mode vs freq vs diameter, the increasing guide wavelength can be plotted big to small end. As seen, the plot is not linear and the guide wavelength starts to get really only as the small end approached cutoff.

Then using Cullen's equation for radiation pressure vs guide wavelength, the decreasing radiation pressure can also be plotted and again is is not linear with decreasing diameter not is it linear with increasing guide wavelength.

While sims like COMSOL and FEKO do show the increasing guide wavelength as the diameter decreases, they don't have the ability, as far as I know, to model the drop in the radiation pressure as the guide wavelength increases.

Sure they do! What you're missing TT, is that while the "guide wavelength" has this behavior per your graph, the wavelength orthogonal to it, reflecting off the sidewalls would have the opposite graph, where the radiation pressure goes up as the wavelength goes down, in the same manner. Shawyer has a "logical" reason why there is no force on the sidewall, but his logic is flawed and not based soundly on Maxwell's equations. There is most certainly pressure on the sidewalls, and that pressure increases toward the small end. Swap blue and purple on your graph.

Work out the length axial component of the radiation pressure on the side walls. Radiation pressure reduces per the cosine of the incident angle.

This why Roger likes long frustums as the cone angle is smaller and thus so too is the resultant axial rad pressure on the side walls.

Roger told me in a properly designed frustum, the axial rad pressure on the side walls is there but has little effect.
It Is Time For The EmDrive To Come Out Of The Shadows

Offline TheTraveller

Maybe I am misunderstanding but are some of you saying that the limitations on the EW budget may have hampered their paper and the results presented therein?

It certainly has allowed the sceptics to have a field day with it I would say.

With what you did receive it seems that you were able to show over the last 5 years, tests producing tantalizing data. Many here (the press sure knows it) must realize the potential advantage of a propelentless EM engine and have to wonder why it wasn't aggressively pursued with a little more funding and resources.

With a 18.5 billion dollar budget NASA should have earmarked more than they did, NASA surely could afford to do it right and put the question to bed, we all can take advantage of it, if it does.

Shell

I do wonder why Glenn never did the promised test of the EW thruster? Surely that would have been gold to see it produce force inside a massive Glenn vac chamber.

Maybe Paul can comment?
It Is Time For The EmDrive To Come Out Of The Shadows

Offline TheTraveller

...snip...

The doorway to a levitator is again open.

YES I will finish the rotary test rig program and release the data as I consider it vital to have data showing Q dropping or not as acceleration occurs and to plot the cavity energy & momentum loss or not against test rig gained angular KE as velocity increases vs power supply energy supply rate change or not.

Phil

Since by GR in the frame of the frustum it can't tell the difference between actual acceleration or being in a gravity field, shouldn't you experience the drop in Q if you try to accelerate in the same axis as earth's gravity?

Seems to me to be a good test of whether it's something acting on an external entity (QV vacuum, Rindler horizons, what have you) versus Shawyer's theory:  Just change the axis of thrust in relation to the earth's gravity.  If there is an acceleration related behavior per Shawyer then you would see a drop in Q in the vertical axis and not in the horizontal axis.  All without the complexity of having to have actual movement.  (assuming you could keep everything else the same of course).

Measuring Q drop or not from axial acceleration is what I'm building my rotary test rig to determine.

Plus measuring any load change or not on the Li Ion batteries.
It Is Time For The EmDrive To Come Out Of The Shadows

Offline TheTraveller

Thus all could change with a new administration coming in. Reports are circulating that Leo and earth science should take a back seat to space exploration.
https://www.yahoo.com/news/trump-administration-set-eliminate-nasa-035716399.html
Dave, what that suggests to me is massive cutbacks to cut costs. It's more about bailing on anything to do with Global Climate Change, than infusing money into exploration. Especially when we see that Elon is willing to put up his own cash to do the Mars shot.

I think you may be right that the private sector is going to be the place to get things done. They are willing to take risks that bureaucracies often shy away from.

Having said that, we all should remember that if it wasn't for John F Kennedy, and a bunch of "steely-eyed-missile-men and women" on the government payroll driving with the best of the aerospace industry, this country would not be the technological powerhouse of engineers and scientists that took knowledge and expertise to the pinnacle the human race has attained.
I agree but today's reality is far more risk adverse imho. Look at those unwilling to entertain anything other than reaction mass research. Fear drives research imo far more than the possibilities of payoff if successful. Reasons are many including tighter budgets yet if research is deemed to be socially responsible, big bucks can flow, I.e. climate research. Trying something risky with a high potential of failure as the moonshot was in JFK's day has been lost. I'm sure interstellar think tanks will continue to collect funds without a charter to produce results other than paperwork, but someone will become Zephraim Cochrane, just don't know how many centuries that will take.

https://en.wikipedia.org/wiki/Wright_Brothers_flights_of_1909

Later that day Wilbur took off again, at 10:18 AM.

He flew over the ocean liner Lusitania and a flotilla of other watercraft on hand for the Hudson-Fulton celebration, many blowing their horns and tooting their whistles when the Flyer appeared overhead.

As Wilbur flew toward the Statue of Liberty, many onlookers feared he would crash into it, but he skillfully circled the statue as planned.

This flight caused a sensation in the press and became an iconic event, despite lasting less than five minutes.

Could be:

As the BBC streamed it live around the world, Roger Shawyer handed Gilo Cardozo a black device, later known to be an "EmDrive Thruster", which he strapped to his back, then harnessed himself to a paraglider and after a short run down the path, very silently rose majestically into the air.

With great skill Gilo flew up and down the Thames and finally did a Victory lap around Westminster before returning to land in front of the BBC cameras.

What a way to make great history and fill Gilo's order books.

Phil
It Is Time For The EmDrive To Come Out Of The Shadows

Offline TheTraveller

TT, re cavity fabrication ..... if memory serves no more than 4/100s" margins? yes?   thnx , FL

Rogers advise was the cavity needs to dimensionally built to +-10x full 5x skin depth.

For copper at 2.45GHz that is +-66um as attached.

Plus the surface needs to be polished to optical requirements and have NO SCRATCHES as any scratches may inhibit proper eddy current formation and thus create distorted internal energy distribution.

Or take a short cut.

https://www.amazon.com/gp/product/B00VPYCZFI/ref=od_aui_detailpages00?ie=UTF8&psc=1

;)

Interesting.

If I knew the size, could quickly determine what freq is need to resonate in TE013 mode.
It Is Time For The EmDrive To Come Out Of The Shadows

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