Author Topic: EM Drive Developments - related to space flight applications - Thread 2  (Read 2100399 times)

Online Mulletron

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In his website he has posted several of his articles.  For example this
relatively recent one on the Mach principle and origin of inertia:

http://mendelsachs.com/wp-content/uploads/articles/the-mach-principle.pdf

In that reference, Sachs convincingly argues against the approach to Mach's
Principle followed by Woodward (-of course- he does not mention  Woodward),
he considers the particle-antiparticle pairs of the quantum vacuum having
a most important effect, while the effect of distant stars is
negligible
:


Quote from: Sachs
I have found in my research program in general relativity, that the primary
contribution to the inertial mass of any local elementary matter, such as an
'electron', are the nearby particle-antiparticle pairs that constitute what
we call the 'physical vacuum'. [The main developments of this research are
demonstrated in my two monographs: General Relativity and Matter, and
Quantum Mechanics from General Relativity]. A prediction of this research
program is that the main influence of these pairs on the mass of, say, an
electron comes from a domain of the 'physical vacuum' in its vicinity, whose
volume has a radius that is the order of 10^(-15) cm. Of course, the distant
stars, billions of light-years away, also contribute to the electron's mass,
though negligibly, just as the Sun's mass contribution to the weight of a
person on Earth is negligible compared with the Earth's influence on this
person's weight! Nevertheless, it was Mach's contention that in principle
all of the matter of the closed system - the nearby as well as far away
constituents - determines the inertial mass of any local matter.

(Bold added for emphasis) ==> this is the anti-thesis of Woodward's
approach to Mach's principle!


This is quite an interesting find and it is refreshing to see that it supports our conclusions (not sure who all agreed with me on this) from the previous thread and forward
(http://forum.nasaspaceflight.com/index.php?topic=29276.msg1266237#msg1266237) during the origin of inertia days; that all the competing theories on the origin of inertia are correct, none are exclusively correct; they they all share a component to inertia. The evidence tells me that inertia is the aggregate effect caused by many different types of interactions happening at once. It also falls in line with the Feynman quote, "All mass is interaction." Even inertial mass? Why not I say.

It is incorrect to state (in my humble view at least) that inertia is
Machian (distant matter) or arises only from vacuum interaction or is
intrinsic to matter itself, gravitational, electromagnetic, whatever.

I saw evidence recently that Mach didn't mean JUST the distant stars/matter when he
envisioned inertia......I didn't know this until now! Is this true?!? Did Woodward acknowledge this?
From page 3 here:
http://mendelsachs.com/wp-content/uploads/articles/the-mach-principle.pdf
"In contrast to this, in his Science of Mechanics Mach said that all of the
matter of the universe, not only the distant stars, determines the inertial
mass of any localized matter."

Break:
I've noticed a delve back into theory recently, which I have been avoiding because of the call for a greater focus on spaceflight applications. Of course I support this because I want to keep our moderator happy and this is his home, we're the guests. I don't want our thread (and work) to go poof again either :(

Is theory off the table?

I assure those who are reading, that this theory we're slinging around here occasionally has the potential to eventually support spaceflight applications. But as I eluded to in my first post in this thread, there
simply aren't spaceflight applications for this emerging technology, YET.
The TRL of this is potential technology is at the concept stage. I tried to stretch a potential application out what's known and didn't do too well. There isn't much space flight application to talk about yet; mostly theory. This may be debunked tomorrow. The space flight application of this post is simply, we better figure out this inertia thing if we want to improve upon and build new and exciting means of space flight.

Those of us who continually plug away on this problem are doing it for good reason. It certainly isn't fun at times reading scientific papers for hours until my eyes go cross. My wife certainly isn't happy with the time I devote to this now. So it is a labor of love. I think many of us really care about solving this problem. I can't stand not knowing how something works for one and the potential payoff for others is enormous if it works. So it is very exciting. Even if it is debunked, we still learn something new in the end, which could be rolled into a new impossible thruster. The potential space flight applications of this post and others like it might (humbly think mine won't) apply to real missions at some point. I do feel that these issues concerning the science behind these potential thrusters needs to be discussed and it seems people are reading, as the the view count of the old thread continues to climb.

Break:
I don't like to double post so I'll add one more subject here.
Turning light into matter:
http://phys.org/news/2014-05-scientists-year-quest.html
I remembered this article this morning. I can see a potential space flight application of this in the future. That is if you take the matter that was created and shoot it out the back end, like an ion drive. Instead of carrying around propellant like xenon, you create it on the fly.
« Last Edit: 01/01/2015 03:27 PM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Offline Notsosureofit

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Trying to put numbers to the Sachs-Schwebel gravitational current, I have not been able to get copies of the Dyatlov (in Russian) papers below but did find a reference to his gravitational polarization density.

This paper is from the old ball-lightning arguments.


http://www.math.nsc.ru/directions/tornado-eng.htm

"The presence of positive and negative gravitational charges gives the vacuum a polarization property in a gravitational field, that, apart from everything else, permits an explanation of the nature of a gravitational current of displacement, arising in gravitational waves.
In his work [11] V. L. Dyatlov gives a high assessment of gravitational polarization of a physical vacuum in the gravitational field of the Earth. By this account, 10^8 kg of negative mass is concentrated onto the upper surface of a cubic volume which is 1 decimeter in size and subjected to a gravitational field, whereas the same amount positive mass is concentrated onto the lower surface of the cubic volume."

[11] Dyatlov V. L.Polarization model of non-homogeneous physical vacuum. Novosibirsk, Publishing of Institute of Mathematics of Siberian branch of Russian Academy of Sciences, 1998, 183 p. (in Russian)

Dyatlov V.L. Linear equations of macroscopic electrogravidynamics.- Moscow, Inst.Teor.Appl.Phys. Acad. Nat.Sci., Preprint No.11, 1995 (in Russian)

Which led to:

http://www.sinor.ru/~che/Vdyatlov1.htm

which references:

52.Terletskiy, Y. P.  Paradoxes of the Theory of Relativity.  Moscow:  Nauka, 1966.  120 pp.

58.Terletskiy, Ya. P., and Yu. P. Rybakov.  Electrodynamics.  Moscow:  Vyssh. shk., 1990.  352 pp.

Which "sounds like" a Russian invention of the Sachs-Schwebel ( quadrigues vs quarternions )

In any event, all I can gather from scanning the equations (so far) is that it looks like they are concerned w/ "gravity currents" as opposed to "gravitational currents".  That makes sense if they are looking at ball-lightning and tornadoes, etc.

I don't know if the polarization density they claim (10^5kg/m^3 @ g) is useful or relevant at this point.





Online Rodal

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...

52.Terletskiy, Y. P.  Paradoxes of the Theory of Relativity.  Moscow:  Nauka, 1966.  120 pp.

58.Terletskiy, Ya. P., and Yu. P. Rybakov.  Electrodynamics.  Moscow:  Vyssh. shk., 1990.  352 pp.

Which "sounds like" a Russian invention of the Sachs-Schwebel ( quadrigues vs quarternions )

...

"The
 Sonobioelectronic and Sonobioelectrogravitic Nature of Life on Earth And Why Pilot-wave Subquantum
Mechanics and Information Is Not Enough"

A. R. BORDON
D. H. HASLER
J.A. SANCHEZ
F.M. MAYE
R. B. SOLINGEN

describes the quadrigue (group of four) of particles of Terletskiy as follows (quadrigue, from the Latin: "A Roman racing chariot drawn by four horses abreast"):

Quote
In accepting negative mass, one must therefore accept the quadrigue (group of four) of particles
of Terletskiy (88), which is neatly buttressed by Dirac’s quadrupling of states in his quantum theory. It
is also a remarkable turn of events in the modeling of the physical vacuum as a polarizing medium.
Terletskiy’s quadrigue is actually four particles (or, actually, four electrical charges, masses, magnetic
moments and spin moments), the sum of which equal zero
– from which, interestingly enough, one can
derive any two pairs of particles in which their electrical charges, masses, magnetic and spin moments
equal zero! This allows theorists to build a basic model of cella (or distinguishable compartments) of
the physical vacuum as a whole-cloth neutral polarizing medium, from which then three kinds of
physical vacuums can manifest: (a) an absolute physical vacuum, represented by the quadrigues; (b) a
physical vacuum of matter, which is made up of particles, one of which is an ordinary one; and (c) a
physical vacuum of antimatter, which is made up of particle pairs, one of which is an antiparticle.
What is most remarkable is that the absolute physical vacuum is described quite well by Maxwell and
Heaviside equations, and thus in the absolute physical vacuum, the polarization model breaks down
into two independent models: the Maxwell theory of electromagnetism, and the Heaviside theory of
gravitational spin. But in physical reality, the relationships of electrical and gravitational polarizations
and of magnetic and spin polarization in the absolute- as well as in the physical matter vacuums come
out as quite a unified system of equations that become the basis of a combined electrogravitodynamic
model of matter electrogravitogeneration (via electrical charges and magnetic polarizations) and
continuum dynamics (via masses and moments of the quantity of movement set by way of the
Heaviside equations).

Apparently a different concept than (Hamilton's) quaternion algebra:

i^2 = j^2 = k^2 = ijk = −1

which is non-commutative.



One motivation for quaternions is that rotations in 3 dimensions ("3D") are not a 3D vector space (we can't combine rotations in 3D space using vector addition). Representations of 3D rotations using 3 scalar values are non linear, they have singularities and they are difficult to combine. To get around these issues one can embed the representation of 3D rotations into a higher dimensional space, in this case the 4D quaternion space.

http://upload.wikimedia.org/wikipedia/commons/thumb/8/85/Euler2a.gif/170px-Euler2a.gif

http://www.toymaker.info/Games/assets/images/yawpitchroll.jpg
« Last Edit: 05/01/2015 03:12 AM by Chris Bergin »

Offline Notsosureofit

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http://www.researchgate.net/publication/242544190_Gravity-Like_Fields_and_Space_Propulsion_Concepts

Interesting experimental results.  Found just by accident.

Edit:  They are still at it, so ?

« Last Edit: 01/02/2015 03:10 PM by Notsosureofit »

Online Rodal

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http://www.researchgate.net/profile/Arbab_Arbab/publication/
51916988_The_unified_quantum_wave_equation/links/0912f50de92ef30406000000.pdf


Quote
We have investigated in this work the quaternionic momentum eigen value problem in quantum mechanics. We have written the wave function, energy and momentum of the particle as quaternionic quantities. The momentum eigen value equation reveals that the scalar and vector parts of the wavefunction are governed by a new wave equation. This is a new equation that we wish it will describe bosons and fermions. When the interaction of the particle with an electromagnetic field is introduced a spin term appeared in the equation of motion. The scalar equation doesn't change due to the interaction of the electromagnetic field with the particle. However, the vector equations are altered. We generalized the ordinary uncertainty relation to quaternionic one. This generalization provides us with the energy momentum relation of Einstein and the remaining uncertainty relations. Hence, by adopting the quaternionic quantum mechanics, namely, Dirac equation, we arrived at a dissipative or generalized
Klein-Gordon equation with a particle spin. This formalism gives rise to the generation of spin angular momentum of the particle when a photon field is introduced in the equation of motion. Further investigation is going on to explore the physics of these two waves
« Last Edit: 05/01/2015 03:11 AM by Chris Bergin »

Offline wembley

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So what TRL would you guys say the devices presented in the "Anomalous Thrust Production...." papers are at right now? I'd say probably a TRL 2. Possibly on the way to a TRL 3, hopefully. 

Well, Cannae were talking about flying theirs in a nanosatellite about a year ago, and I suspect that is still ongoing. The Chinese appear to be more cautious but are somewhere around 4+. Shawyer certainly claimed to be at 4 some time ago. And if rumour is to be believed, an aerospace company has pushed Shawyer's work on some from there.

No, it's TRL-1.  Basic research has not even established sufficient evidence of anything anomalous to convince even a small part of the mainstream physics community.

Being believed by the mainstream community has nothing to do with TRL. If it works, it works. And if the Chinese fly their Emdrive (possibly this year?) and get acceleration, I doubt they'll care what anyone else thinks however loudly they say it can't be true.

I suspect these things really will be operational before a lot of the mainstream starts accepting them, the will to disbelieve is that strong.

Offline Notsosureofit

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http://www.researchgate.net/profile/Arbab_Arbab/publication/51916988
_The_unified_quantum_wave_equation/links/0912f50de92ef30406000000.pdf


Quote
We have investigated in this work the quaternionic momentum eigen value problem in quantum mechanics. We have written the wave function, energy and momentum of the particle as quaternionic quantities. The momentum eigen value equation reveals that the scalar and vector parts of the wavefunction are governed by a new wave equation. This is a new equation that we wish it will describe bosons and fermions. When the interaction of the particle with an electromagnetic field is introduced a spin term appeared in the equation of motion. The scalar equation doesn't change due to the interaction of the electromagnetic field with the particle. However, the vector equations are altered. We generalized the ordinary uncertainty relation to quaternionic one. This generalization provides us with the energy momentum relation of Einstein and the remaining uncertainty relations. Hence, by adopting the quaternionic quantum mechanics, namely, Dirac equation, we arrived at a dissipative or generalized
Klein-Gordon equation with a particle spin. This formalism gives rise to the generation of spin angular momentum of the particle when a photon field is introduced in the equation of motion. Further investigation is going on to explore the physics of these two waves

Very nice, if I'm reading it right, there may be the implication that the spins of the counter-propagating cavity photons could add to 2 in an interaction.  But, at the moment, I don't see that generating enough force.  (who knows at this point, .... it would need a very high vacuum energy density ?)

Added: (18) to (24) is the argument for translating the cavity dispersion to the "doppler plane" to calculate the accelerated frame of reference. (in a different context)

Insight ??:  It seems here that work must be done to install the cavity photons within the limiting boundary conditions of the cavity and that produces a potential energy component which does not appear in the AFR which eliminates the dispersion and doppler shifts the photons.  Since we are holding the cavity static we do not see the energy expenditure, only the static initial force on the unbalanced cavity.  The work done is a good starting number.  Someone must have done that calculation. (he says w/ a straight face ... been there !)

And that force could drop off dramatically under acceleration w/o knowing the energy. In fact it must as a function of the cavity Q.

But that brings up a further question.  Unless the work done is a scalar function, maintaining the acceleration in an isolated system may introduce that compensating momentum which would render the whole point mute.

So the place to start is probably the radiation pressure integrated over the boundary of the cavity compared to the free photon case. (not quite the Shawyer case)
« Last Edit: 05/01/2015 03:12 AM by Chris Bergin »

Offline Star One

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So what TRL would you guys say the devices presented in the "Anomalous Thrust Production...." papers are at right now? I'd say probably a TRL 2. Possibly on the way to a TRL 3, hopefully. 

Well, Cannae were talking about flying theirs in a nanosatellite about a year ago, and I suspect that is still ongoing. The Chinese appear to be more cautious but are somewhere around 4+. Shawyer certainly claimed to be at 4 some time ago. And if rumour is to be believed, an aerospace company has pushed Shawyer's work on some from there.

No, it's TRL-1.  Basic research has not even established sufficient evidence of anything anomalous to convince even a small part of the mainstream physics community.

Being believed by the mainstream community has nothing to do with TRL. If it works, it works. And if the Chinese fly their Emdrive (possibly this year?) and get acceleration, I doubt they'll care what anyone else thinks however loudly they say it can't be true.

I suspect these things really will be operational before a lot of the mainstream starts accepting them, the will to disbelieve is that strong.

You could end up getting a situation with people still throwing cold water on this just as someone flies past their window in a flying car. :)

Offline tchernik

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I agree. Even now, without full assurance of these phenomena's existence (without playing favorites, any single one of them being true would be disruptive), the philosophical rejection it causes seems to be way above the expected from new scientific fields or incipient domains.

Yes, I also think it is very possible engineers could earn the merit of using this first, making the applications come before science at large even accepts its existence.

And this could happen in China before the West. Their own existing results, if confirmed and proven to exist to their own authorities, would be worth of a practical test in the short term.

Offline ThinkerX

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Ok, paging Doctor Rodal for a translation here (from Not so sure of its' link);

Quote


Source





Article: Physics of Extreme Gravitomagnetic and Gravity-Like Fields for Novel Space Propulsion and Energy Generation 

Jochem Hauser, Walter Dröscher

 
[Hide abstract]
ABSTRACT: In 2006 Tajmar et al. reported on the measurements of extreme gravitomagnetic fields from small Nb rings at cryogenic temperatures that are about 18 orders of magnitude larger than gravitomagnetic fields obtained from GR (general relativity). Cifuolini in 2004 and the NASA-Stanford Gravity Probe-B experiment in 2007 confirmed the Lense-Thirring effect as predicted by GR (gravitomagnetic fields generated by a rotating massive body, i.e. Earth) within some 10%. In 2007 gravitomagnetic fields generated by a rotating cryogenic lead disk were measured by Graham et al. Though these measurements were not conclusive (the accuracy of the laser gyrometer was not sufficient to produce a standard deviation small enough) their experiment seems to have seen the same phenomenon reported earlier by Tajmar et al., termed parity violation. This means that gravitomagnetic fields produced by the cryogenic rotating ring or disk vary substantially and change sign for clockwise and counter-clockwise directions of rotation. The experimental situation therefore occurs to be contradictory. On the one hand GR has been confirmed while at the same time, there seems to be experimental evidence for the existence of extreme gravitomagnetic fields that cannot be generated by the movement of large masses. If these experiments can be confirmed, they give a clear indication for the existence of additional gravitational fields of non-Newtonian nature. As was shown by the GP-B experiment, measuring gravitomagnetic fields from GR poses extreme difficulties. Therefore a novel physical mechanism should exist for the generation of gravity-like fields, which might also provide the key to gravitational engineering similar to electromagnetic technology

Quote
: Emerging Physics for Novel Field Propulsion Science 

Jochem Hauser, Walter Dröscher

 
[Hide abstract]
ABSTRACT: All space vehicles in use today need some kind of fuel for operation. The basic physics underlying this propulsion principle severely limits the specific impulse and/or available thrust. Launch capabilities from the surface of the Earth require huge amounts of fuel. Hence, space flight, as envisaged by von Braun in the early 50s of the last century, will not be possible using this concept. Only if novel physical principles are found can these limits be overcome. Gravitational field propulsion is based on the generation of gravitational (gravity-like) fields by manmade devices. In other words, gravity-like fields should be experimentally controllable. Present physics believes that there are four fundamental interactions: strong (nuclei), weak (radioactive decay), electromagnetism and Newtonian gravitation. As experience has shown for the last six decades, none of these physical interactions is suitable as a basis for novel space propulsion. None of the advanced physical theories like string theory or quantum gravity, go beyond these four known interactions. On the contrary, recent results from causal dynamical triangulation simulations indicate that wormholes in spacetime do not seem to exist, and thus even this type of exotic space travel may well be impossible. Recently, novel physical concepts were published that might lead to advanced space propulsion technology, represented by two additional long range gravitational-like force fields that would be both attractive and repulsive, resulting from interaction of gravity with electromagnetism. A propulsion technology, based on these novel long range fields, would be working without propellant


Online RotoSequence

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« Last Edit: 01/03/2015 07:09 AM by RotoSequence »

Online Stormbringer

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if it is the initial martin Tajmar discovery he later recanted due to discovering the flow of his cryogenic coolant was the source of his interesting phenomenon. Unfortunate. However that explanation does not illuminate whether he think there is a nonspurious effect lurking after his error is factored out or not. After all he is definitely not the only researcher who thinks his kind of setup affects gravity. Podkletnov for example. There must be some reason this is so.
When antigravity is outlawed only outlaws will have antigravity.

Online Mulletron

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http://www.emdrive.com/EmDriveForceMeasurement.pdf

New info:
Some clarification from Shawyer. Helps to clear up some of the arguments we had about how Shawyer uses thrust and reaction, and which way it moves.
« Last Edit: 01/03/2015 12:51 PM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Online Mulletron

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Very nice, if I'm reading it right, there may be the implication that the spins of the counter-propagating cavity photons could add to 2 in an interaction.  But, at the moment, I don't see that generating enough force.  (who knows at this point, .... it would need a very high vacuum energy density ?)


I bolded spin 2 above. It immediately caught my eye because gravitons are spin 2 massless particles (if they exist). Don't know what to make of it yet, but it jumped right off of the page when I saw it. Very interesting work you're doing. I really think you were on to something with dispersion too. It makes way more sense to approach radiation pressure differences leading to thrust using your ideas than how Shawyer explains it with his group velocity model.
« Last Edit: 01/03/2015 01:04 PM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Online Stormbringer

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http://www.preposterousuniverse.com/blog/2013/10/03/guest-post-lance-dixon-on-calculating-amplitudes/

Quote
Along the way, Zvi, John Joseph and Henrik, thanks to the time-honored method of “just staring at” the loop integrand provided by unitarity, also stumbled on a new property of gauge theory amplitudes, which tightly couples them to gravity. They found that gauge theory amplitudes can be written in such a way that their kinematic part obeys relations that are structurally identical to the Jacobi identities known to fans of Lie algebras. This so-called color-kinematics duality, when achieved, leads to a simple “double copy” prescription for computing amplitudes in suitable theories of gravity: Take the gauge theory amplitude, remove the color factors and square the kinematic numerator factors. Crudely, a graviton looks very much like two gluons laid on top of each other. If you’ve ever looked at the Feynman rules for gravity, you’d be shocked that such a simple prescription could ever work, but it does. Although these relations could in principle have been discovered without unitarity-based methods, the power of the methods to provide very simple expressions, led people to find initial patterns, and then easily test the patterns in many other examples to gain confidence.

These guys won the Sakurai Prize for Physics.
When antigravity is outlawed only outlaws will have antigravity.

Offline Notsosureofit

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All I can say so far is, that I think that if the cavity dispersion relation has an asymmetric variation in at least one spatial dimension, then there exists an accelerated frame of reference such that the dispersion is eliminated [and the cavity acts as an open system ?] (ie. the boundary condition is nullified, the photons act as free photon wavefunctions, the impedance matches that of the vacuum [?]) The Sachs-Schwebel anomalous current "looks like" it might contain this relation.  Conservation of 4-momentum is still open to question.

Offline birchoff

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http://www.emdrive.com/EmDriveForceMeasurement.pdf

New info:
Some clarification from Shawyer. Helps to clear up some of the arguments we had about how Shawyer uses thrust and reaction, and which way it moves.

Hold the phone... am I reading this right. You can only ever measure thrust if the cavity is accelerating? So just sitting on a flat floating stationary table top should yield no force, the same with when the cavity is moving at constant velocity. Did I mis interpret that pdf?

Online Stormbringer

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if so that pushes it into Dr Woodward and vis inert or "fictitious" fields such as inertia, and gravity. (I'm currently reading Woodward's book )
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Online Rodal

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http://www.emdrive.com/EmDriveForceMeasurement.pdf

New info:
Some clarification from Shawyer. Helps to clear up some of the arguments we had about how Shawyer uses thrust and reaction, and which way it moves.

Hold the phone... am I reading this right. You can only ever measure thrust if the cavity is accelerating? So just sitting on a flat floating stationary table top should yield no force, the same with when the cavity is moving at constant velocity. Did I mis interpret that pdf?
if so that pushes it into Dr Woodward and vis inert or "fictitious" fields such as inertia, and gravity. (I'm currently reading Woodward's book )

Unlike the concepts of displacement, (and its time rates: velocity, acceleration) and strain (which can be mathematically defined in terms of geometry), the concept of "force" is intuitive and has been impossible to mathematically define intrinsically except in terms of other variables. (Although Cauchy and most recently Truesdell made valiant attempts).

Forces can never be measured directly.  Forces are always measured indirectly: for example measuring the resulting acceleration (and calculating the inertial force as F=m*a) or measuring a strain (and calculating an average Force=(cross-sectional Area)*(modulus of Elasticity)*strain ) or measuring a displacement (and calculating Force=(spring stiffness)*displacement).

It is not practical to use a "balance scale" to measure unknown, time-varying-forces



EDIT: Notwithstanding the above (true) statements I find Shawyer's writing to be confusing and easily lead to confusion.  NASA Eagleworks used a torsional pendulum to figure out the force produced by an initially static (truncated cone) EM Drive.   NASA reported to have figured out the EM Drive forces from the EM Drive measured displacement , using a calibration Force=stiffness*displacement.  Unfortunately NASA did not clearly specify whether the displacement (for the truncated cone) was in the direction of the small end or the direction of the large end of the truncated cone.
« Last Edit: 01/03/2015 09:24 PM by Rodal »

Offline frobnicat

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This "clarification" by Shawyer can hardly be interpreted at all. It states that a reaction force equal and opposite to the thrust is to be expected when not accelerating (reaction from a support) "so is Newtonian" but then plays with orientation conventions and decides that "This situation is unique to a propellantless thruster such as EmDrive and analogies with conventional devices are pointless." Ha !

So we are left wondering what makes "propellantless Newtons" special compared to "usual Newtons". I agree (with Rodal) that, as far as conventional Newtons are concerned, measurement of force needs some kind of displacement, but for constant force such displacement reaches a stable equilibrium (static situation) where R=T and both can then be determined by said dispacement. Shawyer's paper clearly states that this shouldn't be expected from "propellantless Newtons".

Quote from: Shawyer
Clearly, in a static situation, where T and R both exist as forces, they will cancel out. Thus any attempt to measure them by simply placing the thruster vertically on a set of scales will fail. If however the thrust is sufficient such that a=-g,then the thruster could be made to hover above the scales.

So if we have a thruster with a ever so slightly below -g the balance records no change (full weight of thruster) and then an infinitesimally small increase of a above -g makes the thruster hover above the balance that all of a sudden will record a weight of 0. How strange transition ! Moreover the same argument of experiment "at rest" => no measured force is made in horizontal setting (Fig 3).

Quote
It therefore appears that a force measurement can only be made in a dynamic environment, ideally by allowing the thruster to accelerate, ...

But isn't a vertical thruster in a dynamic environment thanks to g ? It's like the  "propellantless Newtons"  can tell the difference between being "restrained" or "unleashed". Not only equivalence principle is broken by such special Newtons, but paradoxes directly relevant to space flight are obvious :
assume such a thruster is mounted at the back of a spacecraft, but between the thruster and this big inertial mass there is a spring (no matter how stiff) and a displacement/stress sensor that tells the Newtons communicated by the thruster to the spacecraft. Take a body small enough (asteroid...) that the thruster is supposed to be able to hover the craft above at constant altitude. In this "static situation" the "propellantless Newtons" can't be measured (by a displacement related to stress of the link between thruster and craft). So I guess a spacecraft expects "conventional Newtons" to hover around: the "propellantless Newtons" can't be communicated from the thruster to useful push on a craft through a conventional link that would allow stress deformation (and therefore conventional measurement)...
Same argument would forbid thrusting at constant speed and constant thrust against a medium (horizontal flight in atmosphere). Worse : if equivalence principle is to hold, can't accelerate a spacecraft in free space as it's the same as hovering at constant altitude in a given gravity field.

Basically, saying a thruster is not stressing a scale's spring is saying that running the thing aboard a ship is useless : the thrust is 0 for all practical purpose. Unless we are speaking of an extending inertia modifying field that goes beyond the inner skin of walls of the thruster and accelerating directly the bulk of the rest of spacecraft (that would then need clarification for the range of such field.)

We could also discuss the orientation conventions : fig1 in the usual sense a reaction pseudo-force like R is opposite to a  (italic for vectors) :  the usual M a = T would go T - M a = 0  and to T + R = 0  (as common sense would tell) that is
R = - Ma and not the opposite.

Now we understand why Shawyer's design of LEO launcher puts pointy end of thruster up, because the thrust is toward the ground (but this is unconventional Newtons...).

This latest paper is moving the goalpost, ideally by allowing the goalpost to accelerate...


« Last Edit: 01/03/2015 11:17 PM by frobnicat »

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