EM Drive Developments - related to space flight applications - Thread 2

[TheTraveller]

Interesting that the thrust seems to be "small end forward". Others (Shawyer, NASA, Juan) see opposite thrust, from the large end.

All tests move towards the small end, including these new tests.  I don't think anyone was shown movement toward the large end...

With the possible exception of Prof. Yang in China.

I may not recall this correctly since I have not read those papers in a long time.  Can somebody point out to an explicit reference showing actual measurements (not the computer simulations by Yang) of which way did Yang's device move ?

Notice that in this chart (by Shawyer), Prof. Yang's thruster and Shawyer's Flight Thruster are shown with measurements in the opposite direction:

Shawyers Thrust is the direction of the internal force imbalance. As a result of that internal force imbalance, the device moves in the Reaction direction.

This is explained in most of his papers.

[RotoSequence]

I just uploaded the video with the upside down test.  in the next days i will start testing the new setup with the adjustable length.

The measured weight on the scale drifts downward with each successive run of the magnetron, becoming a greater and greater negative value each time the power is cycled. How much does this anomaly impact the measured displacement of the EM drive?

[deltaMass]

It's not a very stable measurement for sure. But we do know that it's in the opposite direction from before.

[zellerium]

...
That's fine and depends on the kind of material used as a dielectric. I was considering teflon with mu about 10^-6 but you were using HDPE and things can be quite different...

Some information from NASA on their experiments with the truncated cone with the HDPE insert:


............................................

Forgive me if this has been answered already, but when did they change the dielectric to HDPE?
The Anomalous thrust paper clearly states that a PTFE slug was used in the Cannae drive and there is no mention of HDPE in the paper.

[SeeShells]

Take a gander at the section on energy conservation here:

http://emdrive.echothis.com/Generic_EM_Drive_Information

Just thinking that maybe there should be a third option:  Since a constant acceleration transforms as a 4-space rotational velocity (?), there may be an invariant for the tensor which allows Energy to Momentum conversion. ?  This would be what, a "false force" driven by the dispersion cycle in the cavity ??  I'm visualizing that cycle as distorted compared to symmetrical cavity which would want to make it (the world line) curve in x,t.

I understand what you're trying to say and I like it on several levels. This is one reason I asked if you had thought of introducing another EM wave into the cavity not in phase, but having the ability to control the phase and frequency. Sorry, it's the old dog with a bone syndrome here.

It somewhat fits this statement.

The general conclusion seems to be that a momentum can be transferred to a body, though the relative magnitudes of the momenta and assumptions appear not to be consistent with one
another.
The main result of this letter is that we demonstrate for
a collection of magnetic dipole scatterers that receive a
classical perturbative correction to its permeability from
an external magnetic field, a non-zero momentum transfer
to the body as a whole. It is a fourth order perturbative
result and requires at least four scattering centres
to be present and held in a rigid configuration. Further,
they should be arranged so that the resulting tetrahedron
(with the four particles placed at the vertices) has
no parity symmetry so that the vacuum photons get to
see a chiral structure. If these conditions are fulfilled
then a non-zero momentum develops which scales as the
fourteenth inverse power of the length scale of the tetrahedron.
Whilst the numerical value of this momentum
for the pure quantum vacuum case is far too small to be
measured experimentally, there are hopes of being able
to measure its classical counterpart. The calculations are
performed using the notation and conventions in [18] and
multiple scattering theory.
http://arxiv.org/pdf/1011.4376.pdf

[Rodal]

...
That's fine and depends on the kind of material used as a dielectric. I was considering teflon with mu about 10^-6 but you were using HDPE and things can be quite different...

Some information from NASA on their experiments with the truncated cone with the HDPE insert:


............................................

Forgive me if this has been answered already, but when did they change the dielectric to HDPE?
The Anomalous thrust paper clearly states that a PTFE slug was used in the Cannae drive and there is no mention of HDPE in the paper.

That's correct. The Brady et.al. report does not mention the dielectric material used in the truncated cone measurements.

ALL the measurements documented in Brady et.al. with the truncated cone having a dielectric were performed with a HDPE dielectric.  The measurements with the PTFE dielectric in the truncated cone are not documented in the Brady et.al. report.  The information came from Paul March, one of the co-authors of the Brady et.al. report.

[Rodal]

Interesting that the thrust seems to be "small end forward". Others (Shawyer, NASA, Juan) see opposite thrust, from the large end.

All tests move towards the small end, including these new tests.  I don't think anyone was shown movement toward the large end...

With the possible exception of Prof. Yang in China.

I may not recall this correctly since I have not read those papers in a long time.  Can somebody point out to an explicit reference showing actual measurements (not the computer simulations by Yang) of which way did Yang's device move ?

Notice that in this chart (by Shawyer), Prof. Yang's thruster and Shawyer's Flight Thruster are shown with measurements in the opposite direction:

Shawyers Thrust is the direction of the internal force imbalance. As a result of that internal force imbalance, the device moves in the Reaction direction.

This is explained in most of his papers.

The attached table shows a column labeled "force direction" which shows, for Prof. Yang's device and for the Flight thruster to have opposite force direction to all the measurements at NASA Eagleworks.

The table shows:

Thruster             Force Direction

NASA                 Thrust
(China)               Reaction
Flight Thruster    Reaction


The images show:

Thust      --> at the BIG END
Reaction --> at the SMALL END


Therefore, it implies

NASA                 Thrust       BIG END
(China)               Reaction     SMALL END
Flight Thruster    Reaction     SMALL END


The one fact we know is what is the direction of the force and the displacement measured at NASA Eagleworks. That force is in the direction of the small diameter.  (No matter whatever Shawyer has written about it, Shawyer cannot speak with more authority about NASA's experiments than Paul March)

Therefore either:

1) According to Shawyer's chart, Prof. Yang's EM Drive moved towards the Big Diameter

or

2) The chart attached by Shawyer is wrong (with respect to the force direction shown for NASA, which Shawyer shows to be towards the Big Diameter)

 

[deltaMass]

No. You are muddling everything up.
The diagrams show "thrust" to be BIG END FORWARD.
The diagrams show "reaction" to be SMALL END FORWARD.
*except for the symmetric case where "DIELECTRIC END FORWARD" is the reaction direction.

I recommend you use that nomenclature. It's unambiguous.

[kdhilliard]

Shawyers Thrust is the direction of the internal force imbalance. As a result of that internal force imbalance, the device moves in the Reaction direction.

This is explained in most of his papers.

So far I've only read Shawyer's Theory Paper V 9.4, in which he writes:

Thus the radiation pressure at the larger end plate is higher than that at the smaller end plate.  The resulting force difference (F_g1 - F_g2) is multiplied by the Q of the resonant assembly.

Now λ_g2 > λ_g1, due to the difference in cross-section, and hence F_g1 > F_g2.  Therefore the resultant thrust T will be T = F_g1 - F_g2 = 2P_0/c (λ_0/λ_g1 - λ_0/λ_g2).

On pg. 5-6 he goes on to discuss thrust reversal at high relativistic speeds of the cavity.  That is not directly relevant to this discussion, but he does argue:

Thus as the velocity of the waveguide increases in the direction of thrust, the thrust will decrease until a limiting velocity is reached when T = 0.

Reading this paper alone, one would assume that the cavity would accelerate large end first due to the force imbalance on the end plates, and that seems to be what he is suggesting on Pg. 5 with "the velocity of the waveguide increases in the direction of the thrust" (presumably as a result of this thrust), but the 2014 summary slide above suggests that Shawyer somewhere argues that this force imbalance somehow causes a reaction in the opposite direction which accelerates the cavity small end first.

Analogously, I understand that if I were "sitting in a tin can, far above the world" and I pressed against the floor, the only way I could maintain that pressure is by bracing myself against the ceiling, and as a result the forces would balance out and my capsule would not accelerate in any direction.  But if somehow I could magically press on the floor harder than I do on the ceiling, the imbalance in forces would cause my capsule to accelerate floor first.  I understand that without the magic holding me in place, I would accelerate toward the ceiling (and thus loose contact with the floor, countering the thrust imbalance), but what is Shawyer's argument that has, in essence, the capsule accelerate ceiling first?

Traveller, can you recommend another of Shawyer's papers to read where I can find this argument?

~Kirk

[Blaine]

Take a look at this refreshingly good quote on Iulian's website.  I never thought about this until I read this quote.  Makes sense to me.



Good news, quite intriguing!!

When comparing the different thrusts, you will also have to take into account that in test 3.1 the thruster has to fight against the upward force of the spring onto which it is attached. This will lower the observed weight change on the scale, but does not necessarily mean the thrust is lower.

[deltaMass]

No. You are muddling everything up.
The diagrams show "thrust" to be BIG END FORWARD.
The diagrams show "reaction" to be SMALL END FORWARD.

I recommend you use that nomenclature. It's unambiguous.

I don't know who are you addressing as "muddling everything up", but Shawyer's chart shows for NASA's experiments with the frustum of a cone, with a dielectric:

Force direction: thrust

which according to you,  "thrust" means in the direction of the BIG END FORWARD

which therefore means force direction towards BIG END

and that's wrong.  The force measured at NASA was towards the small end, that's one thing we know for a fact, no matter what Shawyer may write about NASA's experiments.

We have discussed the issue of force measurement and displacement measurement at NASA at length with Paul March in these threads.

Sorry but your nomenclature for me is as ambiguous as all get out

[TheTraveller]

Traveller, can you recommend another of Shawyer's papers to read where I can find this argument?

~Kirk

Page 4 explains it.

[TheTraveller]

Sorry but your nomenclature for me is as ambiguous as all get out

Page 4 explains it.

[Lobo]

Welcome to the thread.   Just a short answer and comment regarding the above points.  It was not Chris's article.  I was one of three authors. 

My Apologies Jose Rodel!  I just now went back and looked at the authors.  My laziness for not having done that first.

Thanks for your response.  I appreciate it.  I don't quite understand all of your references, but that gives me a point to start digging a little further.  :-)

[TheTraveller]

I don't know who are you addressing as "muddling everything up", but Shawyer's chart shows for NASA's experiments with the frustum of a cone, with a dielectric:

Force direction: thrust

which according to you,  "thrust" means in the direction of the BIG END FORWARD

which therefore means force direction towards BIG END

and that's wrong.  The force measured at NASA was towards the small end, that's one thing we know for a fact, no matter what Shawyer may write about NASA's experiments.

We have discussed the issue of force measurement and displacement measurement at NASA at length with Paul March in these threads.

Page 4 explains it.

Note also Shawyers reference to TM01 cutoff & guide wavelength.

[Notsosureofit]

Take a gander at the section on energy conservation here:

http://emdrive.echothis.com/Generic_EM_Drive_Information

Just thinking that maybe there should be a third option:  Since a constant acceleration transforms as a 4-space rotational velocity (?), there may be an invariant for the tensor which allows Energy to Momentum conversion. ?  This would be what, a "false force" driven by the dispersion cycle in the cavity ??  I'm visualizing that cycle as distorted compared to symmetrical cavity which would want to make it (the world line) curve in x,t.

I understand what you're trying to say and I like it on several levels. This is one reason I asked if you had thought of introducing another EM wave into the cavity not in phase, but having the ability to control the phase and frequency. Sorry, it's the old dog with a bone syndrome here.

The short answer is yes.  As RODAL mentioned above, putting a pair of frequencies at the half-power points of the resonance.  I did my thesis on cylindrical cavity resonance that way, many long years ago.

[Lobo]

The bottom line is that nobody understands how this thing works.

Like the Wave Motion Engine that was given to us by Iscandar?

It works, we just don't know how...

[phaseshift]

I've seen reference to the Demonstrator Thrusters DF as .844 in 3 different Shawyer documents now.  Hmmmm something seems amiss

[phaseshift]

I've seen reference to the Demonstrator Thrusters DF as .844 in 3 different Shawyer documents now.  Hmmmm something seems amiss

Can you please provide the links (or attach pdf) to all 3 references havign DF = 0.844 ?

[SeeShells]

Take a gander at the section on energy conservation here:

http://emdrive.echothis.com/Generic_EM_Drive_Information

Just thinking that maybe there should be a third option:  Since a constant acceleration transforms as a 4-space rotational velocity (?), there may be an invariant for the tensor which allows Energy to Momentum conversion. ?  This would be what, a "false force" driven by the dispersion cycle in the cavity ??  I'm visualizing that cycle as distorted compared to symmetrical cavity which would want to make it (the world line) curve in x,t.

I understand what you're trying to say and I like it on several levels. This is one reason I asked if you had thought of introducing another EM wave into the cavity not in phase, but having the ability to control the phase and frequency. Sorry, it's the old dog with a bone syndrome here.

The short answer is yes.  As RODAL mentioned above, putting a pair of frequencies at the half-power points of the resonance.  I did my thesis on cylindrical cavity resonance that way, many long years ago.

Thank you, from one old dog to another. Like I've told others I remember when engineering/science was a rock hitting a rock, then it all turned to dirt. That short answer is long on my understanding.