EM Drive Developments - related to space flight applications - Thread 8

[meberbs]

Not the electrical power, the mechanical power which is F*v such that the thrust then remains constant.

Some toy electric airplane motors deliver about 0.088N/W (27oz for 85W). Given an initial thrust of about 7.5N, the thrust doesn't diminish by a factor of 10 as the plane picks up speed of 10m/s then 20 as the speed gets to 20m/s. It's constant up to and at the equilibrium with the drag. But if the air had zero drag, the acceleration would be constant.

The Shawyer probe is powered at about 200KW with about 30KW going to RF power. The Cannae probe has less than 100W RF power.

No, the faster the plane is moving relative to the air, the more power it takes to accelerate the air to produce the same force. Drag is an additional effect. Doing the calculations in different frames (the rest frame of the air, or some other constant velocity frame) will all lead to the same conclusion that the power required to generate a constant force varies with the speed of the air relative to the plane. (which is independent of reference frame, because it is the difference of velocities, so all calculate the same power and force, and that power/ force varies with airspeed.)

Example (using a discrete event instead of continuous to make it easier to follow, so energy (E) instead of power, change in momentum (Δp) instead of force. Subscript a means air, p means plane, 1 means initial, 2 means final.

conservation of momentum:
m_a*v_a1 + m_p*v_p1 = m_a*v_a2 + m_p*v_p2
Δp = -m_a*(v_a2 - v_a1 ) = m_p*(v_p2 - v_p1 )

conservation of energy:
0.5*m_a*v_a1² + 0.5*m_p*v_p1² + E = 0.5*m_a*v_a2² + 0.5*m_p*v_p2²
Rearrange to solve for E, group the terms, and apply a²-b² = (a+b)(a-b) pull out the parts which are equal to Δp, and you get:
E = 0.5*Δp*( (v_p2 - v_a2) + (v_p1 - v_a1) )

Therefore, for a constant change in the plane's momentum, the engine needs to output more energy if the plane's airspeed is higher, and all frames agree on this amount of energy, since it comes from frame-independent potential energy (chemical/electrical).

In any real system, there are many other complications (temperature changes, motor efficiency as function of RPM etc.), but this effect will still be there.

No, the engine puts out a fixed power and thrust. The plane then accelerates to its max speed for that power and is in a steady state. It's all very simple but you're over complicating it. According to you, the thrust drops the instant the plane moves. Not true. But this isn't a perfect example since the air defines a fixed frame.

Overcomplicating? I literally described the simplest ideal case of a vehicle pushing on a medium to accelerate, and showed that your assertion of fixed power for fixed thrust is false. Repeating your basic assertion that I just disproved shows a complete lack of comprehension on your part.

"According to you, the thrust drops the instant the plane moves." - No, not according to me. According to basic mechanics, as the plane's velocity relative to the air increases, either the generated force decreases, the power delivered to the motor increases, or something in between.

Velocity is relative but acceleration is absolute. Thus, if the EmDrive works, it produces a force and thus an acceleration regardless of anything. There is no way for it to "know" what velocity it's going such as to "know" it's kinetic energy is in danger of growing at a rate beyond which the power it is supplying can handle. The only limitation must be that the force it produces is proportional to the power it uses to produce that force.

If the EmDrive works by "pushing" against something (i.e. some unknown field or other objects in the universe via gravity assist), it perfectly "knows" its velocity relative to the medium/objects it's pushing against.  And just like with any other "pushing" mechanism, the higher your velocity, the harder it is to push.  This is required for CoM/CoE to be observed, as has been explained multiple times in this thread.

You've just defined a fixed absolute frame for the universe, something Relativity forbids. What would be required for CoM/CoE preservation is that the pushing is the same in all frames. In effect, every frame is equivalent and can be "pushed" against equally. Every frame of the universe must be the Center of Momentum frame.

You don't push against frames. If there is some medium that the emDrive pushes against (lets just say dark matter for now), than the work required to push against the dark matter depends on the relative velocity between the drive and the dark matter, which creates the "special frame" of the medium (the local dark matter rest frame) This kind of special frame is allowed by special relativity, just like the frame of the air is a special frame for an airplane.

Your continued search for a better than photon rocket constant force/power system is getting tiring, since it has been shown multiple times and ways that this simply does not work in Newtonian Mechanics or special relativity.

[Bob012345]

Not the electrical power, the mechanical power which is F*v such that the thrust then remains constant.

Some toy electric airplane motors deliver about 0.088N/W (27oz for 85W). Given an initial thrust of about 7.5N, the thrust doesn't diminish by a factor of 10 as the plane picks up speed of 10m/s then 20 as the speed gets to 20m/s. It's constant up to and at the equilibrium with the drag. But if the air had zero drag, the acceleration would be constant.

The Shawyer probe is powered at about 200KW with about 30KW going to RF power. The Cannae probe has less than 100W RF power.

No, the faster the plane is moving relative to the air, the more power it takes to accelerate the air to produce the same force. Drag is an additional effect. Doing the calculations in different frames (the rest frame of the air, or some other constant velocity frame) will all lead to the same conclusion that the power required to generate a constant force varies with the speed of the air relative to the plane. (which is independent of reference frame, because it is the difference of velocities, so all calculate the same power and force, and that power/ force varies with airspeed.)

Example (using a discrete event instead of continuous to make it easier to follow, so energy (E) instead of power, change in momentum (Δp) instead of force. Subscript a means air, p means plane, 1 means initial, 2 means final.

conservation of momentum:
m_a*v_a1 + m_p*v_p1 = m_a*v_a2 + m_p*v_p2
Δp = -m_a*(v_a2 - v_a1 ) = m_p*(v_p2 - v_p1 )

conservation of energy:
0.5*m_a*v_a1² + 0.5*m_p*v_p1² + E = 0.5*m_a*v_a2² + 0.5*m_p*v_p2²
Rearrange to solve for E, group the terms, and apply a²-b² = (a+b)(a-b) pull out the parts which are equal to Δp, and you get:
E = 0.5*Δp*( (v_p2 - v_a2) + (v_p1 - v_a1) )

Therefore, for a constant change in the plane's momentum, the engine needs to output more energy if the plane's airspeed is higher, and all frames agree on this amount of energy, since it comes from frame-independent potential energy (chemical/electrical).

In any real system, there are many other complications (temperature changes, motor efficiency as function of RPM etc.), but this effect will still be there.

No, the engine puts out a fixed power and thrust. The plane then accelerates to its max speed for that power and is in a steady state. It's all very simple but you're over complicating it. According to you, the thrust drops the instant the plane moves. Not true. But this isn't a perfect example since the air defines a fixed frame.

Overcomplicating? I literally described the simplest ideal case of a vehicle pushing on a medium to accelerate, and showed that your assertion of fixed power for fixed thrust is false. Repeating your basic assertion that I just disproved shows a complete lack of comprehension on your part.

"According to you, the thrust drops the instant the plane moves." - No, not according to me. According to basic mechanics, as the plane's velocity relative to the air increases, either the generated force decreases, the power delivered to the motor increases, or something in between.

Velocity is relative but acceleration is absolute. Thus, if the EmDrive works, it produces a force and thus an acceleration regardless of anything. There is no way for it to "know" what velocity it's going such as to "know" it's kinetic energy is in danger of growing at a rate beyond which the power it is supplying can handle. The only limitation must be that the force it produces is proportional to the power it uses to produce that force.

If the EmDrive works by "pushing" against something (i.e. some unknown field or other objects in the universe via gravity assist), it perfectly "knows" its velocity relative to the medium/objects it's pushing against.  And just like with any other "pushing" mechanism, the higher your velocity, the harder it is to push.  This is required for CoM/CoE to be observed, as has been explained multiple times in this thread.

You've just defined a fixed absolute frame for the universe, something Relativity forbids. What would be required for CoM/CoE preservation is that the pushing is the same in all frames. In effect, every frame is equivalent and can be "pushed" against equally. Every frame of the universe must be the Center of Momentum frame.

You don't push against frames. If there is some medium that the emDrive pushes against (lets just say dark matter for now), than the work required to push against the dark matter depends on the relative velocity between the drive and the dark matter, which creates the "special frame" of the medium (the local dark matter rest frame) This kind of special frame is allowed by special relativity, just like the frame of the air is a special frame for an airplane.

Your continued search for a better than photon rocket constant force/power system is getting tiring, since it has been shown multiple times and ways that this simply does not work in Newtonian Mechanics or special relativity.

Basically, your just saying EmDrive can't work so why discuss it. We discuss it because that's what thus thread is set up to discuss. I'm not the only one saying it might work and if it does, you will just have to change your perspective.

It's already been proven that with photon recycling, better than a photon rocket is possible. The EmDrive seems to offer a potential billion times improvement over a photon rocket.

[meberbs]

Basically, your just saying EmDrive can't work so why discuss it. We discuss it because that's what thus thread is set up to discuss. I'm not the only one saying it might work and if it does, you will just have to change your perspective.

It's already been proven that with photon recycling, better than a photon rocket is possible. The EmDrive seems to offer a potential billion times improvement over a photon rocket.

I am not just saying the emDrive can't work, you keep adding things to what people are saying. For consistency with the things we know about how the universe works, there are constraints on how the emDrive could work. I gave one example of how it could work right in my last post, somehow pushing against dark matter. There are other theories that are plainly inconsistent (e.g. Shawyer's claims that the device obeys conservation of momentum, but does not push against or transfer momentum to anything else.)

And how many times do you need it explained to you that a recycling photon rocket is not constant force/power, when you account for the relative motions of the spacecraft and whatever the other mirror is attached to? Anything more efficient has some form of propellant or medium (the mirror for the recycling laser beam), which causes a relative velocity to exist that causes the force/power ratio to vary with velocity.

[X_RaY]

The problem is that the interpretation depends on the relative viewpoint / observing from a defined relative reference frame. (Even it is one who is accelerated itselfs. Everything is relative. )
http://www2.lbl.gov/MicroWorlds/teachers/massenergy.pdf
Nevertheless any accelerating device have to satisfy GR (plus CoM & CoE), not only SR as suggested by R.Shawyer.

Till now it's on of the best proven theories we have until it's maybe replaced by a more complete one sometime in the future.

[Gilbertdrive]

The basic point is that you say the EmDrive, if it works at all, will stop accelerating as it's kinetic energy grows faster than its electrical energy input. You're claiming you know Shawyer, Fetta and anyone else who shows a fixed thrust for a fixed electrical power doesn't understand how physics works if they claim that acceleration will just continue. Myself and others believe if it works at all, nothing can limit the acceleration since all observer frames are arbitrary. I believe the energy conundrum is only an apparent violation.

Velocity is relative but acceleration is absolute. Thus, if the EmDrive works, it produces a force and thus an acceleration regardless of anything. There is no way for it to "know" what velocity it's going such as to "know" it's kinetic energy is in danger of growing at a rate beyond which the power it is supplying can handle. The only limitation must be that the force it produces is proportional to the power it uses to produce that force which is the point Woodward made.

What you claim as a basic point from me is a total mistake about what I have repeated, including in preceding answers to you. I am deeply disappointed that it happens after so many exchanges.

I never claimed that the Emdrive would necessary stop accelerating as it's kinetic energy grows faster than its electrical energy input. I have claimed that if the Emdrive doesn't steal energy to something else, and still gives constant thrust for constant imput power, it breaks CoE. I also repeated several times the example of Gravity Assist, what is a perfect example of stolen Energy, and had been precedently used by Dr Rodal.

How can you remove this condition ?

Also, even if this condition was no satisfied, I had written that it would break CoE. Not that it was impossible. The only thing that I consider, in the context of these threads to be impossible to break are the maths and the logic.

Also, I do not understand how you can consider than a ship with a small 200kVe generator coming back on the earth after 20 years of space travel, and making an impact and releasing the energy of 5 million Hiroshima bombs without having stolen energy to anything else is only an apparent violation ? What do you need to make a violation not only apparent ? destroying the entire solar system  with the energy of a battery AAA ?

You think There is no way for it to "know" what velocity it's going such as to "know" it's kinetic energy is in danger of growing at a rate beyond which the power it is supplying can handle.

It depends of how it works.
For example, if the Emdrive is a way of pusing against distant masses, with a new interaction, the emdrive could "know" it's Kinetic Energy just like a car knows it's Kinetic energy when pushing against the road, or a maglev train "knows" it's Kinetic energy relatively to the rail.

If the emdrive is a way of pushing against Dark matter, and if the movement applies to dark matter, the Kinetic energy in the referential of the dark matter the Emdrive is pushing against will be relevant.
Etc.

The claim that the emdrive can give thrust superior to P/V in any inertial reference frame closes these possible theories. How do you know that these theories are impossible ?

[mwvp]

...Now in late 2016 Roger has released a radical cryo EmDrive, that based on the cavity TC from the Force generation curves, would have a Ql of ~3x10^9 and specific force of ~10,000N/kWrf. Seems Roger has been busy.

Several here have stated YBCO will not work at microwave frequencies. Seems their opinion may need to be updated.

143kg/6kWrf is a specific force of 234N/kWrf which is not that far above the 145N/kWrf figure for LHe cooling of the Experimental cryo EmDrive data.

I googled for "vacuum breakdown voltage" a while ago, and read that it's difficult to do better than 100MW in a resonant (superconducting accelerator) cavity. 10^3 watts and 10^9 Q gives you around 10^12 watts. So I guess the good news is, with heroic effort, a 10N thruster can be powered by a wifi transmitter.

Another consideration is acceleration. If the Q is 10^9 and frequency 10^9 Hz, the bandwidth is around 1 Hz, hence the maximum acceleration around 1 m/s^2.

But 10^7 - 10^8 seems a reasonable maximum attainable Q, even with heroic effort. So even as a believer, I hardly expect to see hover-cars using Shawyer's technology.

Perhaps Bose-Einstein condensate in some new material.

[rq3]

Interesting data from Roger's 2009 paper on his Experimental YBCO thruster where he published experimentally measured surface resistance data for YBCO on Sapphire data at 3.83GHz. He also stated the experimentally measured Qu was 6.8x10^6, cooled with LN2, which would produce a specific force of 41N/kWrf, increasing to 145N/kWrf if cooled by LHe.

I then plotted the results for cooling with LH2 and LHe as attached.

He further states in the paper that the data was from his 1st Experimental cryo EmDrive and that he has moving to build a Demonstrator EmDrive, following the development process and names of the non cryo EmDrives.

That was in 2009. Now in late 2016 Roger has released a radical cryo EmDrive, that based on the cavity TC from the Force generation curves, would have a Ql of ~3x10^9 and specific force of ~10,000N/kWrf. Seems Roger has been busy.

Several here have stated YBCO will not work at microwave frequencies. Seems their opinion may need to be updated.

143kg/6kWrf is a specific force of 234N/kWrf which is not that far above the 145N/kWrf figure for LHe cooling of the Experimental cryo EmDrive data.

Would you please make it clear that the "41N/kWrf", "145N/kWrf", "~10,000N/kWrf", "143kg/6kWrf", "234N/kWrf" are all speculated based on Q and are not actually measured? I think many may not read carefully enough and may get incorrect impression.

The Qu of 6.8x10^6 and Rs of 78 uOhm for the YBCO on Sapphire thin film at 77K and 3.83GHz are experimentally measured values.

There are established equations that link the other values together. One follows the other as does Ohm's law. Shall I then question every Ohm's law calculation because it has not been experimentally measured?

Roger measured the Qu in his 1st experimental YBCO EmDrive and then measured the surface resistance change vs temp at 3.82GHz. It is simple math to do the calc at other values of Rs once the Qu vs Rs at one temp is known.

This is known as EmDrive Engineering 101.

Does Roger have resistance measurements for his YBCO coating on sapphire for DC? It should go to exactly zero at the critical temperature. The plot showing reduced RF impedance at reduced cryogenic temperatures is, um, suspect. Please confirm.

[WarpTech]

I caught some flack for making Q a variable of the coordinates inside the frustum. So here are the thrust and group velocity equations using the damping factor instead, which is an acceptable variable function of the coordinates inside the frustum. Now, the thrust is proportional to Q, but it is also proportional to the 4-gradient of the damping potential.

Todd

[zen-in]

In Shawyer's paper he states the surface resistivity data is "based on specified manufacturer's data" (quoted from his paper).   In all probability he does not possess any of the sapphire substrate HTS described in his paper and he has not built the device you describe as "an experimental HTS thruster"   There are thousands of papers published every year devoted to esoteric measurements of small sections of HTS in carefully controlled laboratory setups.  Shawyer has extrapolated from that with his claim an HTS em-drive thruster is possible and you have taken a much bigger leap by claiming he has built "an experimental HTS thruster".

He states he built an Experimental cryo YBCO on Sapphire EmDrive thruster. Even shared a photo.

Minus the 2 images (Fig 12 and Fig 13) here is what Roger wrote:

7.SUPERCONDUCTING DEMONSTRATOR  PROGRAMME

The first phase of this programme was an experimental superconducting thruster.  This low power, HTS device operates at liquid nitrogen temperature, and is designed for very high Q and consequently high specific thrust.

Fig 12 Experimental Superconducting Thruster as attached

Fig 12 shows the thruster, which operates at 3.8 GHz, and was designed using an update of the software used for the previous S band designs. Super-conducting surfaces are formed from YBCO thin films on sapphire substrates.

Small signal testing at 77 deg K confirmed the design, with a Q of 6.8x10^6 being measured.

Fig 13 shows the surface resistivity of the superconducting thruster based on specified manufacturer’s data, updated for the measured data.

Fig 13 Surface Resistivity as attached.

For the Demonstrator Thruster, cooling will be by liquid hydrogen. The design resistivity at 20deg K is therefore taken as 11.8 x 10-6 Ohms. This value was then used in the same design software used for the experimental 2G thruster. The resulting thrust was calculated as 143kg for 6kW input.

At DC HTS cooled below 77 K has a resistance very close to zero Ohms.   Superconductivity is not absolute.  Temperature, current, and magnetic fields all limit the superconductivity as shown in the figure below.   In the diagram to the left one axis is temperature, another current, and the third the magnetic around the HTS.   Superconductivity exists only inside the bubble.  And AC or microwave energy introduces a loss mechanism in HTS.   



Surface resistivity measurements at microwave frequencies are high when compared to the DC resistance of superconductors.   These measurements are done with very low RF power levels.    Higher RF power would introduce self heating from the RF losses destroying the superconductivity.     Superconductor physics is a lot more complicated than simply applying Ohm's law to one or two points and extrapolating.

http://www.enea.it/it/pubblicazioni/EAI/anno-2012/n.-3-maggio-giugno-2012/high-temperature-superconductivity-challenges-and-perspectives-for-electric-power-applications

[TheTraveller]

Correction

Superconducting cavities use a different equation to calculate Rs (Surface Resistance) than metal cavities. This means that while in a metal cavity Q scales with the square of the metal conductivity. in a superconducting cavity Q scales linear with Rs changes.

This means my chart showing calculated Q and specific force at different YBCO on Sapphire temperatures assumed Rs vs Q square scaling and was too low. I have attached the revised chart, which reflects Q scaling linear as Rs alters.

I also have data that suggests as of 2014, YBCO substrates had achieved 11uOhm Rs at 3.83GHz as against Roger's 2009 78uOhm Rs at 3.83GHz, which would increase the attached Q and specific forces ~7x.

Based on the 2014 RS data and the resultant Rs at LHe temps the Q is calculated to be 6.2x10^8 which is not that far from the 3x10^9 Q as calculated from the new patents 5x TC force curves. The 3.83GHz Rs only needs to drop to 2.3uOhm to achieve that Q.

All of which does support Roger's new EmDrive design may truly be capable of 1,000kg/kWrf specific force.

Updated calculations attached.

[TheTraveller]

Surface resistivity measurements at microwave frequencies are high when compared to the DC resistance of superconductors.   These measurements are done with very low RF power levels.    Higher RF power would introduce self heating from the RF losses destroying the superconductivity.     Superconductor physics is a lot more complicated than simply applying Ohm's law to one or two points and extrapolating.

Of course there needs to be sufficient thermal heat sinking capability in the cooling system to handle any cavity heating so to keep the HTS in a superconducting state.

Likewise as to the max H field before the superconducting state is exited.

Have found examples of HST cavities that are filled with Rf energy way higher than what would be pumped into a EmDrive. In fact as the cavity Q climbs and the specific force generated climbs, the Rf energy needed to produce force X drops and does the resultant cavity heating.

It is EmDrive Engineering 101 that works out the needed cavity energy to achieve force X and keep the HST cooled and operating below it's max H field intensity.

All doable. Just engineering.

[TheTraveller]

I caught some flack for making Q a variable of the coordinates inside the frustum. So here are the thrust and group velocity equations using the damping factor instead, which is an acceptable variable function of the coordinates inside the frustum. Now, the thrust is proportional to Q, but it is also proportional to the 4-gradient of the damping potential.

Todd

Todd,

You may find it interesting, some information I recently became aware of.

Seems if a dielectric is placed in the small end of the frustum, the Thrust force vector is big to small. However if you remove the dielectric, the Thrust force vector alters 180 deg to small to big and increases ~3-4x the dielectric Thrust force.

This is the same non dielectric Thrust vector direction as Roger measured in his detailed non dielectric Demonstrator report.

To make that clear:

Dielectric @ small end, Thrust force vector Big >>> Small
No dielectric, Thrust force vector Small >>> Big, same cavity as above, 3-4x dielectric Thrust force value

Thrust force is a static force that can be measured on a scale or torsion pendulum, is there all the time there is resonant Rf in the cavity and doesn't need free acceleration to be measured.

I trust the data source.

[Peter Lauwer]

......
Thrust force is a static force that can be measured on a scale or torsion pendulum, is there all the time there is resonant Rf in the cavity and doesn't need free acceleration to be measured.
.....

You come up again with that concept of 'force-less free acceleration'. I believe Shawyer also talks about it. It would be the most revolutionary thing to emerge from the EMdrive, doesn't it?
To me it merely sounds like an excuse to explain null-results of experiments.  Even gravitation acts as a force. It is very hard to imagine what the nature of such a 'force-free acceleration' would be.

Cheers, Peter

[TheTraveller]

......
Thrust force is a static force that can be measured on a scale or torsion pendulum, is there all the time there is resonant Rf in the cavity and doesn't need free acceleration to be measured.
.....

You come up again with that concept of 'force-less free acceleration'. I believe Shawyer also talks about it. It would be the most revolutionary thing to emerge from the EMdrive, doesn't it?
To me it merely sounds like an excuse to explain null-results of experiments.  Even gravitation acts as a force. It is very hard to imagine what the nature of such a 'force-free acceleration' would be.

Cheers, Peter

The EmDrive generates 2 forces:

1) Static Thrust force which is generated by the guide wavelength variation with changing cavity diameter. The Thrust force vector follows longer guide wavelength to shorter guide wavelength direction in the resonant cavity. In a non dielectric cavity, the Thrust force vector is small to big end. It has been measured by many experimenters using a scale or a torsion pendulum, which is just a fancy scale. No movement of the cavity is required for the Thrust force to be generated. Well Ok a little movement happens as all scale like devices have a spring constant.

2) Accelerative Reaction force, which is equal in value but opposite in force vector to the Thrust force. It can only be measured via A = F/M on a rotary test rig or linear test rig that allows free acceleration to occur.

Most EmDrive experimenters measure the static Thrust force.

I know of only 2 EmDrive experiments that have measured the accelerative Reaction force. One being Roger's 2006 Demonstrator testing on a rotary air bearing test rig and another that I can't share but has very high credibility. I'm working to make that 3.

Both of these forces can and have been measured, but not at the same time, including the Thrust force vector change that happens when you add a dielectric to the small end of the cavity.

Now we need a theory that predicts what has been physically measured. So far Roger's is the closest I know of.

[Peter Lauwer]

......
Thrust force is a static force that can be measured on a scale or torsion pendulum, is there all the time there is resonant Rf in the cavity and doesn't need free acceleration to be measured.
.....

You come up again with that concept of 'force-less free acceleration'. I believe Shawyer also talks about it. It would be the most revolutionary thing to emerge from the EMdrive, doesn't it?
To me it merely sounds like an excuse to explain null-results of experiments.  Even gravitation acts as a force. It is very hard to imagine what the nature of such a 'force-free acceleration' would be.

Cheers, Peter

The EmDrive generates 2 forces:

1) Static Thrust force which is generated by the guide wavelength variation with changing cavity diameter. The Thrust force vector follows longer guide wavelength to shorter guide wavelength direction in the resonant cavity. In a non dielectric cavity, the Thrust force vector is small to big end. It has been measured by many experimenters using a scale or a torsion pendulum, which is just a fancy scale. No movement of the cavity is required for the Thrust force to be generated. Well Ok a little movement happens as all scale like devices have a spring constant.

2) Accelerative Reaction force, which is equal in value but opposite in force vector to the Thrust force. It can only be measured via A = F/M on a rotary test rig or linear test rig that allows free acceleration to occur.

Most EmDrive experimenters measure the static Thrust force.

I know of only 2 EmDrive experiments that have measured the accelerative Reaction force. One being Roger's 2006 Demonstrator testing on a rotary air bearing test rig and another that I can't share but has very high credibility. I'm working to make that 3.

Both of these forces can and have been measured, but not at the same time, including the Thrust force vector change that happens when you add a dielectric to the small end of the cavity.

Now we need a theory that predicts what has been physically measured. So far Roger's is the closest I know of.

But does this 'Accelerative Reaction force' emerge from Roger's 'theory' ? (the image I have of his theory is that he explains it from the imbalance of forces of reflected EM waves on the inside of the cavity. The addition of this Accelerative Reaction force seems rather artificial then.)

Good that you are doing experiments to prove the existence of these forces. I'm curious (but showing a movie on youtube with a moving device on an air bearing bed will probably not convince me (I do not trust my own eyes). I would have to do extensive tests with it myself.)

But it certainly a good thing that there are 'believers' (excusez le mot) and sceptics on this forum! We should not avoid though discussions. (when I started to set up a replication experiment I was for 99.9% certain it was all due to heat effects and magnetic fields, etc. Now I would set that to 90%. So my believe in the possibility that there really is an anomalous effect already increased 100-fold!). '-)

Keep up the good work.
Peter

[TheTraveller]

But it certainly a good thing that there are 'believers' (excusez le mot) and sceptics on this forum! We should not avoid though discussions. (when I started to set up a replication experiment I was for 99.9% certain it was all due to heat effects and magnetic fields, etc. Now I would set that to 90%. So my believe in the possibility that there really is an anomalous effect already increased 100-fold!). '-)

Keep up the good work.
Peter

Hi Peter,

Thanks.

Very soon I trust that will be 0% doubt.

[RERT]

SPR filed a document at Companies House yesterday, dated 21-Oct. It confirms no changes to shareholdings since 21-Oct-15, the death of one of the minor shareholders notwithstanding.

[meberbs]

......
Thrust force is a static force that can be measured on a scale or torsion pendulum, is there all the time there is resonant Rf in the cavity and doesn't need free acceleration to be measured.
.....

You come up again with that concept of 'force-less free acceleration'. I believe Shawyer also talks about it. It would be the most revolutionary thing to emerge from the EMdrive, doesn't it?
To me it merely sounds like an excuse to explain null-results of experiments.  Even gravitation acts as a force. It is very hard to imagine what the nature of such a 'force-free acceleration' would be.

Cheers, Peter

The EmDrive generates 2 forces:

1) Static Thrust force which is generated by the guide wavelength variation with changing cavity diameter. The Thrust force vector follows longer guide wavelength to shorter guide wavelength direction in the resonant cavity. In a non dielectric cavity, the Thrust force vector is small to big end. It has been measured by many experimenters using a scale or a torsion pendulum, which is just a fancy scale. No movement of the cavity is required for the Thrust force to be generated. Well Ok a little movement happens as all scale like devices have a spring constant.

2) Accelerative Reaction force, which is equal in value but opposite in force vector to the Thrust force. It can only be measured via A = F/M on a rotary test rig or linear test rig that allows free acceleration to occur.

Most EmDrive experimenters measure the static Thrust force.

I know of only 2 EmDrive experiments that have measured the accelerative Reaction force. One being Roger's 2006 Demonstrator testing on a rotary air bearing test rig and another that I can't share but has very high credibility. I'm working to make that 3.

Both of these forces can and have been measured, but not at the same time, including the Thrust force vector change that happens when you add a dielectric to the small end of the cavity.

Now we need a theory that predicts what has been physically measured. So far Roger's is the closest I know of.

Your 2-forces description remains equivalent to saying that pushing something to the left makes it move to the right contradicting F=m*a.

I have asked you many times to answer 2 simple questions about a simple, real system that mimics the forces that the emDrive produces according to Shawyer. Your inability or unwillingness to answer them indicates that you either don't understand simple mechanics, or you are not interested in rational discussion. Either way, this there is no point in me providing further explanations of why your claims don't make sense until you answer the questions.

[PotomacNeuron]

....

But it certainly a good thing that there are 'believers' (excusez le mot) and sceptics on this forum! We should not avoid though discussions. (when I started to set up a replication experiment I was for 99.9% certain it was all due to heat effects and magnetic fields, etc. Now I would set that to 90%. So my believe in the possibility that there really is an anomalous effect already increased 100-fold!). '-)

Keep up the good work.
Peter

Do you have updates of your experiment? For example, photos of the settings. Thanks.

[Peter Lauwer]

Very soon I trust that will be 0% doubt.

As someone who tries to be a Bayesian scientist (now and then), I should never assign either 0 or 100% doubt or certainty.

[https://en.wikipedia.org/wiki/Bayesian_probability]