### Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 2326293 times)

#### Rodal

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1660 on: 06/13/2015 12:52 PM »
I now suspect there are two discrete phenomenon at work inside the emDrive.

The first effect is very close to that described in Mr. Sawyer's theory paper.  By ray tracing the paths of photons in a continuously tapered asymmetric waveguide you can see a small force is generated.

The second effect is that discovered by the Nasa team, that a dielectric placed in an otherwise non-thrusting cavity will cause it to generate a force.  I no longer believe this is due to the Sawyer effect.  I believe this second effect is due to a very non-intuitive behavior of radiation pressure.

My physics textbook (Serway) says that Radiation pressure P is equal to the Plank constant times the frequency of light divided by C. (1)

The speed of light in a medium is equal to the speed of light in a vacuum divided by the index of refraction (n) (2)

Substituting 2 into 1 yields:

P= hf/(c/n)
or, to make it more obvious...
(3)  P = hfn/c

Radiation Pressure is increased by the index of refraction of the material surrounding the bounce.

This effect has been confirmed experimentally (Jones, 1978) Radiation pressure is greater if the target mirror is immersed in a material with a higher index of refraction.

(citation)
The Measurement of Optical Radiation Pressure in Dispersive Media
R. V. Jones and B. Leslie
Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences
Vol. 360, No. 1702 (Apr. 4, 1978) , pp. 347-363
http://www.jstor.org/stable/79586
(/citation)

Serway also says that radiation pressure P is valid for emission or absorption, but is actually 2P for reflection.  The cause for this is obvious.  A reflection is actually an absorption followed by an emission. (4)

The combined effect of (3) and (4) is, I suspect, the cause for the Nasa/dielectric effect.

Consider a one-dimensional system where a photon is trapped in the vacuum space between two loss-less front-surface mirrors.  it will bounce back and forth practically forever, generating no net thrust.

At the left mirror impact the mirror receives a left push of -1 on absorption, and a left push of -1 on emission.  The acceleration on the left mirror is -2.  When the photons strike the right mirror, +1 for absorption, +1 for emission.  The net thrust is zero.

Now consider the case where the left mirror is immersed in another lossy material with the index of refraction of 1.5.

 Action Thrust from Action Net thrust (start) 0 Transition v-d Absorption at vacuum-fluid boundary. -1 -1 Transition v-d Emission at vac/fluid boundary. 1.5 0.5 Dielectric Reflection Absorption at left mirror -1.5 -1 Dielectric Reflection Emission at left mirror. -1.5 -2.5 Transition d-v Absorption at the fluid-vacuum boundary 1.5 -1 Transition d-v Emission at the fluid-vacuum boundary -1 -2 Vacuum Reflection Absorption at the right Mirror 1 -1 Vacuum Reflection Emission at the right Mirror 1 0 (return to start condition)

The radiation pressure is greater during the phase where the photons are in the lossy dielectric.  Loss of one of these these photons during that phase results in a asymmetric force.  This asymmetry is, I propose, the cause of the Nasa effect.  The index of refraction of PTFE at microwave frequencies is complex, so this absorption and loss can occur.

I propose to confirm the second effect experimentally by creating a traditional round symmetrical microwave resonator and operating it with and without a PTFE endplate inside the existing metal plate.  If I am correct, this circular-non-tapered resonator will generate thrust when the PTFE endplate is in place.

Do I fundamentally misunderstand any concepts here?

Elizabeth Greene
[email protected]

Edited: copy and pasted the wrong theory, added table.
Hi Elizabeth,

Welcome to the EM Drive thread !!!

Thank you for a great post.  Thank you for the reference to the classic paper by Jones and Leslie.

Yes, the effect of the index of diffraction has been pointed out by Fran de Aquino, for example, see his paper "How the Thrust of Shawyer’s Thruster can be Strongly Increased"  http://bit.ly/1f8zJLV

But the issue we are struggling with is that if there is no mass or no energy being emitted outside the device, how can anything done inside it accelerate its center of mass?  Doing so would run counter to the law of conservation of momentum, one of our most cherished laws in Physics.

I can move a spacecraft by hitting it with tennis balls from the outside.  Or by using a magnet on it from the outside.   I cannot move the center of mass of a spacecraft by asymmetrically using a magnet on the inside or asymmetrically hitting its internal walls with tennis balls.  One needs to either emit mass or energy to the outside to have propulsion.

How do you satisfy conservation of momentum ?.

Besides the issue of conservation of momentum, there appear to be issues with conservation of energy as well, because if this effect can produce acceleration in response to input power, then the kinetic energy can increase as the square of the velocity without bounds, quickly overtaking the input power leading to an apparent paradox.  As @frobnicat pointed out one could use 2 or more EM Drives internally, rotating in order to produce power as a generator, and it looks like the EM Drive itself would be able to power itself and produce free energy, breaking conservation of energy.

Another issue with explaining this in terms of asymmetric index of refraction by the use of dielectrics, is that Shawyer claims that it is better not to use dielectrics, as he abandoned their use, and the highest force per InputPower has been reported by teams (Shawyer's in the UK and Prof. Yang in China) using no dielectric inserts inside the EM Drive.  See this table of experimental results that we put together:  http://emdrive.wiki/Experimental_Results.  A comparison is made in this table to an ideal, perfectly collimated photon rocket, because it is another intriguing feature of the EM Drive that its claimed force/Input Power is orders of magnitude greater than the one of a photon rocket.

« Last Edit: 06/13/2015 01:24 PM by Rodal »

#### ElizabethGreene

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1661 on: 06/13/2015 02:11 PM »
Rodal, thank you for the kind reply.  I am giddy to see the Aquino paper.  It means I'm on the right path.  That the paper is only 8 months old is even more encouraging.  I simply need to run faster and catch up.

#### rfmwguy

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1662 on: 06/13/2015 02:12 PM »
Re. the Baby EmDrive data: if friction be modelled going as w2, then in the absence of a driving force
w(t) -> e-t
Unfortunately, the shape of that does not fit the shape of the undriven data, which is roughly a straight line of negative slope.
Therefore the friction model isn't right.

Neither does friction going as w fit: it yields
w(t) -> 1/(1 + t)

The friction model which fits the data is constant frictional force, independent of the rotational velocity.
I've already analysed that and shown that the driving force cannot be determined without more data about the experiment. Specifically we need to know either
a) the frictional torque, or
b) the moment of inertia of the cavity platform (I) AND the lever arm (R) of the cavity

In any case, I am abandoning the w2 friction model.

Too bad it's a dead end, but I'm not surprised. Like I speculated on an earlier post, after the rig has been spinning for a time, the air in that bell jar is probably in some kind of "steady state" vortex losing energy through boundary layer interactions with the jar walls.  Maybe an analogy is a ducted fan.

Still must give a hats-off the Aachen team for their novel approach. Perhaps it will lead to something more.

Nice Job Germany! (meine Heimat vom Darmstadt)

#### SeeShells

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1663 on: 06/13/2015 02:29 PM »
Rodal, thank you for the kind reply.  I am giddy to see the Aquino paper.  It means I'm on the right path.  That the paper is only 8 months old is even more encouraging.  I simply need to run faster and catch up.
Welcome aboard Elizabeth! It was nice to read your ideas and you will find the people here from interested lurkers, DYIers, techs, engineers and phds all hoping to see the next generation in propulsion become real. It's a truly great group.

I see where your leading with your ideas and I find them quite insightful, you seem to violate CoM but don't let that be a brick wall just because someone tells you it does.  We're working with human laws based on understanding of mother nature and if your ideas seem to violate a law take it to the next step and prove it doesn't or glory be it does (and that is another story)!

Shell

#### Star One

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1664 on: 06/13/2015 02:36 PM »
Second test of the baby EM drive and problems with oscillation. I think they are looking for suggestions to resolve this?

« Last Edit: 06/13/2015 02:42 PM by Star One »

#### Rodal

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1665 on: 06/13/2015 02:43 PM »
Oscillations of the Baby EM Drive in a torsional pendulum: struggling with the same problem that has plagued these measurements since Maxwell: what has been known as the "gas effect".  For 30 years in the 19th century they struggled with this until a Russian succeeded at eliminating it in the year 1900...by using a vacuum chamber to perform the measurements.

They are talking about using water to dampen the oscillations.  Experience with torsional pendulums show that they would be better off using oil to dampen the oscillations.  They should also eliminate the heat sources in the chamber: the lights in the chamber, as they cause natural convection currents in the air.  Best thing at the moment is to use a vacuum chamber, otherwise they will just dampen oscillations but still have a steady-state effect of convection.

////////////////

Note on the prograde and retrograde measurements (particularly to deltaMass):  the response clearly exhibits nutation released from rest (which they describe with Electrical Engineering language: "looking like a rectified sine curve"  ? , perhaps Movax is an EE student at Aachen University ? ).  The gyroscopic equations have to be taken into account.  Unfortunately the full form of the gyroscopic equations are nonlinear differential equations so one may have to perform a numerical analysis (depending on the amplitude of the motion).

I am not inclined to analyze this at the moment because I am skeptical of not taking taking into account the effect of the magnetic forces being applied to it to levitate it as well, and what role they may play in the experiment.  Also, they have not performed enough experiments yet.  They need to perform more experiments,, including null configuration.

It is frustrating that they have not yet disclosed the internal dimensions of the Baby EM Drive, (last time I checked), although people have asked them in their blog.  NASA (Paul March) and Iulian Berca promptly disclosed their geometry, etc.  Need the internal dimensions to find out what are the nearby natural frequencies and mode shapes, to know what mode shapes are being excited, and their participation.
« Last Edit: 06/13/2015 04:22 PM by Rodal »

#### Flyby

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1666 on: 06/13/2015 03:37 PM »

I can move a spacecraft by hitting it with tennis balls from the outside.  Or by using a magnet on it from the outside.   I cannot move the center of mass of a spacecraft by asymmetrically using a magnet on the inside or asymmetrically hitting its internal walls with tennis balls.  One needs to either emit mass or energy to the outside to have propulsion.

A risky step I'm taking here, but I do not agree with the magnet or tennis ball analogy...
I know moment is depending on mass and velocity. When masses are not equal, velocity has to be proportional at the inverse ratio of the mass.

When the ball hits the interior wall, it looses a part of its momentum due to speed (energy) loss. Energy loss comes from the elastic deformation of both wall (very little) and the tennis ball.

Some energy will also be lost due to air resistance when traveling back to the other side, where another impact will generate a slightly smaller , but opposite momentum, after which the ball travels back, etc...

The amount of times it bounces back and forth, is basically an indirect representation our Q value. Normally, as we all learned, it should equalize out in the end, giving a nul result...

But what happens if that ball suddenly changes from an elastic object into a non elastic object, like clay?
when all the kinetic energy is absorbed and all of its momentum is transferred to one side?

Isn't that what happens when an electromagnetic wave is attenuated?

Do not forget that the tennis ball is actually coming from outside the space station, just as the electromagnetic waves are pumped from the outside into the frustum. (as Todd previously said).

Do not be fooled by the illusion that it ricochets inside the space station.
The starting energy of the ball has not been created inside the space station, hence seen from within the space station, there was no action(ball throwing) prior to the reaction (ball moving).

The ball entered the space station at full kinetic energy level through a small portal, never to get out again.

It also means, as has been identified (probably correctly) that the lower your Q and the faster you can convert you tennis ball into a clay ball, the bigger the remaining momentum will be...

The error in the analogy is that you describe the tennis ball to have started its action within the space station, were in reality, it didn't.

now.. i'll throw myself for the lions...

« Last Edit: 06/13/2015 03:41 PM by Flyby »

#### Rodal

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1667 on: 06/13/2015 04:00 PM »
...But what happens if that ball suddenly changes from an elastic object into a non elastic object, like clay?
when all the kinetic energy is absorbed and all of its momentum is transferred to one side?

Isn't that what happens when an electromagnetic wave is attenuated?...
(*)

No difference whatsoever in that case.

I have actually modeled this effect successfully vs. experiments.  When a high speed impact takes place, the impacting object constitutive behavior changes from perfectly elastic, to plastic strain-hardening, to perfectly plastic.  At high enough velocities, it even changes to a fluid behavior.  This can and has been analyzed to take into account material anisotropy and strain-rate effects on the constitutive equations.  Even change of phase has been taken into account.

All of that respects conservation of momentum and conservation of energy.

In a few words: change of constitutive behavior from elastic to plastic, as well as change of phase, or even chemical or nuclear reactions still satisfy conservation of momentum and conservation of energy.  This has been verified to great accuracy and precision.

So, if the analogy fails (all analogies are imperfect) it must be on another basis (other than change in constitutive behavior).  I think it has to do more with the nature of a photon gas (photons can be created and eliminated, and they are not continuum particles, but display Quantum behavior).  If the EM Drive is not an artifact, I think that energy is getting out somehow (as for example @aero is finding out in his analysis).

__________

(*) Sorry, no, that's not what happens in the attenuation we are discussing.  The attenuation we are discussing is geometrical attenuation that does not result in heat losses, but rather change of phase.
« Last Edit: 06/13/2015 04:05 PM by Rodal »

#### kdhilliard

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1668 on: 06/13/2015 04:22 PM »
Do not forget that the tennis ball is actually coming from outside the space station, just as the electromagnetic waves are pumped from the outside into the frustum. (as Todd previously said).

Do not be fooled by the illusion that it ricochets inside the space station.
The starting energy of the ball has not been created inside the space station, hence seen from within the space station, there was no action(ball throwing) prior to the reaction (ball moving).

The ball entered the space station at full kinetic energy level through a small portal, never to get out again.

It also means, as has been identified (probably correctly) that the lower your Q and the faster you can convert you tennis ball into a clay ball, the bigger the remaining momentum will be...

The error in the analogy is that you describe the tennis ball to have started its action within the space station, were in reality, it didn't.

Your example with the balls fired into the station from the ground (or from a different, unattached space station) certainly will yield a thrust.  It's analogous to a dark, non-reflective solar sail, which is half as efficient as a shiny, reflective solar sail.  But an EmDrive's magnetron is attached to the frustum and both parts accelerate (or don't) as a unit, so you need to modify your example so that the balls are fired from a tennis ball cannon which is attached to the station.  Do that and the action of initially accelerating the balls must be taken into consideration.

~Kirk

#### Flyby

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1669 on: 06/13/2015 04:58 PM »
(*) Sorry, no, that's not what happens in the attenuation we are discussing.  The attenuation we are discussing is geometrical attenuation that does not result in heat losses, but rather change of phase.

Hmmm... isn't "attenuation" the opposite of "amplification" , consequently meaning a decrease in amplitude and the elongation of the frequency till in the end, it becomes zero?
A change of phase is just linear shift.

Although I understand that, when the wave hits the endplate, the effect of both situations means the wave no longer resonates between the plates , because frequency and distance have to match, I do not understand where the phase shift comes from....

I can understand that the waves change amplitude and frequency as they're dragged along the frustum side walls, because they loose some of their energy and consequently have to change in frequency/amplitude. At least that's how I understood (maybe wrongly?) Todd's idea.

I don't see why a wave would just shift it's phase, but keep amplitude and frequency the same?

I'm just trying to visualize what's happening and how a momentum transfer in a frustum could happen...

ah well, until we got some serious proof it actually works all theories mean nothing. Sad to see we got 2 DIY that have to postpone their builds, due to circumstances. All hopes are now on the EagleWorks setup.. that's, if they're ever allowed to report back to us in the future...

#### vulture4

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1670 on: 06/13/2015 05:02 PM »
All the RF fed into the resonator is ultimately attenuated. The primary mode of attenuation is the induction of eddy currents in the enclosure, which are in turn radiated as em energy  (was this measured externally?) which might produce inductive repulsion against other conductors in the area, or as heat which may produce force even at low pressures through thermal recoil of air molecules.  A microwave oven magnetron can easily put out a kilowatt of RF power, it has to go somewhere.

My goal experimentally would be to buid a small metal box with a heating element and a thermistor on one surface, mounted on a load cell to measure the change in force when the box is heated.
« Last Edit: 06/13/2015 05:13 PM by vulture4 »

#### aero

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1671 on: 06/13/2015 05:14 PM »
And if you have problems operating meep, ask and I'll try to answer .

Thanks. I ran a couple examples & looked up your Bradycone.txt file from your recent 5/31 post. Any reason you're using the Harminv rather than the frequency domain solver? It would seem to be a better choice for speed, if all that's desired is the steady-state mode pattern.

No reason, just haven't looked into the solver. If you're running it, I would appreciate a code snippet that does it.
Retired, working interesting problems

#### Rodal

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1672 on: 06/13/2015 05:26 PM »
My interpretation of kr on these diagrams is, 2pi x number of wavelengths. So these diagrams show 5, 10, 15 wavelengths. You can understand that a frustum that is 1/2 wavelength long, does not have enough length to absorb much energy, and it should be several wavelengths long I think. It makes a good resonator, but a very poor thruster.

Todd

r is the spherical radial distance from the apex of the cone as defined here:

Don't forget the factor of 2 Pi in the definition of k

k r =  2 Pi r /wavelength

in the horizontal axis is a dimensionless expression of spherical radial distance, so that it can be applied for any size fustrum.

For example,  k r = 5 means

2 Pi r /wavelength = 5

so that it means a spherical radial distance of

r = 5 wavelength / ( 2 Pi )
= 0.80 wavelength

so:

kr                                   5               10           15
r (wavelengths)            0.80          1.59         2.39

You have to get very close to the apex of the cone to get geometrical attenuation (unless θ is small)

Now that we have populated with data the Experimental Data Table in the wiki: http://emdrive.wiki/Experimental_Results , particularly the mode shapes used for different experiments and the geometrical data in spherical coordinates, we can use this information (mining this powerful database) to compare vis-a-vis Zeng and Fan's paper ( https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-17-1-34&id=175583 ) on geometrical attenuation of waveguides to critically examine whether it applies to the EM Drive experiments.

Synopsis of the "geometrical theory of attenuation" for EM Drive thrust:  it is proposed that momentum is transferred from energy stored in the cavity through standing waves in resonance with a quality factor Q, to evanescent waves.  Evanescent waves are created due to the tapering geometry of the cone, which cuts-off modes at the small end of the truncated cone.  Standing waves cannot transfer momentum but evanescent waves can transfer momentum.  Hence it is posited that an ideal EM Drive design is one that maximizes evanescent waves at the small end of the cone  and yet it allows enough standing waves at the big end to store energy that can be transferred to the small end of the EM Drive.

I have calculated the following data:

Description              k r1         θ           f (GHz)  Force/InptPwr (N/kW)   Dielectric
Shawyer Demo       11.61     Pi/9.3    2.45     0.080-0.243                 none
Shawyer  Flight       14.24     Pi/8.6    3.85     0.235-0.408                 none
NASA Brady c         12.26     Pi/12      1.88    0.021                            HDPE
Yang                       35.71     Pi/29     2.45     1.070                           none

Here k r1 is the product of the wavenumber (k = 2 Pi f / c , where f is the excitation frequency and c is the speed of light in the medium) times the smaller spherical radius r1.  k r is the dimensionless unit of distance from the cone's apex used by Zeng and Fan in Figures 2 and 3 below.

θ is the cone half-angle expressed in Radians as Pi/n where n is a number, for easy comparison with the charts of Zeng and Fan shown below.

All of these experiments were conducted in TE01p mode (transverse electric with a magnetic axial field), therefore they have to be compared with the TE01 charts from Zeng and Fan shown below.

Notice:

1) It is incorrect to focus solely on the cone half-angle  θ to characterize the dependence of attenuation and phase shift on the geometry of the truncated cone.  The attenuation and the phase shifts are a function of both the cone half-angle and the spherical radial distance from the apex of the cone.  Observe that while Yang has a cone half angle 3 times smaller than Shawyer, her EM Drive has a small spherical radius that is 3 times longer than Shawyer's.  So, Yang uses a much smaller cone angle, but the distance from the small base to the apex of the cone is 3 times longer, so she ends up with practically the same small diameter that Shaywer uses.

2) Both the cone half-angle and the small spherical radius are important to describe attenuation and phase.  If one has to use only one parameter one might as well use the small base diameter.  What the designers need is to use small base diameters that are somewhat smaller than the cut-off wavelength, in order to enhance attenuation and phase shift.  This is consistent with the formulas of Shawyer's Design Factor, McCulloch's formula and @Notsosureofit's formula.  All these formulas prescribe the use of the smallest diameter possible at the small end.

3) Concerning attenuation (α/k in Fig. 2 attached):  The value of kr in the EM Drive TE01 experiments ranges from 12 to 36 which is way to the right in the horizontal axis of Zeng and Fan, in the region of small attenuation.  Although Yang uses a small cone half-angle (Pi/29) her value of the spherical radius is large (36), it lies outside the range shown by Zeng and Fan.  Shawyer's value of α/k in Fig. 2 is somewhere between 0.5 and 1.0, based on his k r of 12 to 14 and his  θ of Pi/9.

4) The important chart is the phase constant (Fig. 3 attached for phase constant β ), which we want as small as possible, in order to transfer momentum.  In that respect, it appears that Shawyer's design gets the smallest phase constant, about  β/k= 0 compared to Yang's β/k = - 0.5, which should translate into greater transfer of momentum for Shawyer.  Since Yang achieved the greatest Force/InputPower it appears that this data presents a challenge to the geometrical attenuation theory (unless "something got lost in translation" from Yang's paper). NASA's geometry is also pretty good but it does not present a challenge to the theory, because NASA is  using a dielectric insert at the small end that lowers the natural frequency and prevents cut-off of modes, hence the geometrical attenuation theory correctly predicts that NASA should get lower thrust forces
« Last Edit: 06/13/2015 08:48 PM by Rodal »

#### Possibles

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1673 on: 06/13/2015 05:50 PM »

I can move a spacecraft by hitting it with tennis balls from the outside.  Or by using a magnet on it from the outside.   I cannot move the center of mass of a spacecraft by asymmetrically using a magnet on the inside or asymmetrically hitting its internal walls with tennis balls.  One needs to either emit mass or energy to the outside to have propulsion.

A risky step I'm taking here, but I do not agree with the magnet or tennis ball analogy...
I know moment is depending on mass and velocity. When masses are not equal, velocity has to be proportional at the inverse ratio of the mass.

When the ball hits the interior wall, it looses a part of its momentum due to speed (energy) loss. Energy loss comes from the elastic deformation of both wall (very little) and the tennis ball.

Some energy will also be lost due to air resistance when traveling back to the other side, where another impact will generate a slightly smaller , but opposite momentum, after which the ball travels back, etc...

The amount of times it bounces back and forth, is basically an indirect representation our Q value. Normally, as we all learned, it should equalize out in the end, giving a nul result...

But what happens if that ball suddenly changes from an elastic object into a non elastic object, like clay?
when all the kinetic energy is absorbed and all of its momentum is transferred to one side?

Isn't that what happens when an electromagnetic wave is attenuated?

Do not forget that the tennis ball is actually coming from outside the space station, just as the electromagnetic waves are pumped from the outside into the frustum. (as Todd previously said).

Do not be fooled by the illusion that it ricochets inside the space station.
The starting energy of the ball has not been created inside the space station, hence seen from within the space station, there was no action(ball throwing) prior to the reaction (ball moving).

The ball entered the space station at full kinetic energy level through a small portal, never to get out again.

It also means, as has been identified (probably correctly) that the lower your Q and the faster you can convert you tennis ball into a clay ball, the bigger the remaining momentum will be...

The error in the analogy is that you describe the tennis ball to have started its action within the space station, were in reality, it didn't.

now.. i'll throw myself for the lions...

Hi there! - nice to be here. Lovely to see people coming together to work on a worthwhile subject for a change. And I hope I can be of service.

I will point out that in this case, even though the energy comes from the outside, the core problem remains. You are imparting energy to a sealed framework that "should" have no influence on the separate framework outside of said space station.

The only chance for this to work is for the machine itself to somehow be enabling information and energy transfer "Through" the space station at a quantum connected level that quite frankly, we don't understand (as yet). I understand this does not help very much, but it is a gentle reminder of where our efforts should be concentrated.

#### deltaMass

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1674 on: 06/13/2015 06:08 PM »
Second test of the baby EM drive and problems with oscillation. I think they are looking for suggestions to resolve this?

I find this quite bizarre. The motion seems to have little to do with the natural frequency or its friction, and little to do with whether the drive is on or off. It seems instead to be showing a chaotic time series of air circulation flows local to the apparatus.

A vacuum chamber is called for!

#### Star One

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1675 on: 06/13/2015 06:22 PM »
Hopefully the vacuum chamber will be communicated successfully to them as the solution.

#### Blaine

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1676 on: 06/13/2015 07:04 PM »
Simple solution to the lighting problem - LED lighting.  tada!
Weird Science!

#### deltaMass

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1677 on: 06/13/2015 07:05 PM »
I just wish I could deduce the absolute thrust. That would let us get a N/W and a N/Kg figure for the wiki.

#### deltaMass

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1678 on: 06/13/2015 07:07 PM »
Baby EmDrive dimensions now released.

Height         24.37mm
diameter1   29.64mm
diameter2   16.12mm
small dameter top edge to centre of injector   5.60mm.

#### aceshigh

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##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #1679 on: 06/13/2015 07:37 PM »
But the issue we are struggling with is that if there is no mass or no energy being emitted outside the device, how can anything done inside it accelerate its center of mass?  Doing so would run counter to the law of conservation of momentum, one of our most cherished laws in Physics.

I can move a spacecraft by hitting it with tennis balls from the outside.  Or by using a magnet on it from the outside.   I cannot move the center of mass of a spacecraft by asymmetrically using a magnet on the inside or asymmetrically hitting its internal walls with tennis balls.  One needs to either emit mass or energy to the outside to have propulsion.

this is where you need Dr White's explanation right? In that case, the virtual particles are everywhere and I guess they move through the device too. Like if it was water and the device a propeller. Somehow it would be interacting with particles that go through the matter of the device?

maybe they just found a way to interact with neutrinos... instead of virtual particles...

depending of the case, IF the measurements are real, EVEN if this can never be used for a space drive, it would still be very interesting from a pure scientific standpoint depending on what is causing the effect.

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