Author Topic: EM Drive Developments - related to space flight applications - Thread 9  (Read 1800760 times)

Offline Monomorphic

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I was surprised that I had never heard of this powerful accelerator. Then I realize I am not the only one who have not.

Long links break the page spanning on NSF. Use this link instead:

http://scitation.aip.org/content/aip/magazine/physicstoday/article/69/12/10.1063/PT.3.3397
« Last Edit: 12/01/2016 06:00 pm by Monomorphic »

Offline DusanC

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I was surprised that I had never heard of this powerful accelerator. Then I realize I am not the only one who have not.

Long links break the page spanning on NSF. Use this link instead:

http://scitation.aip.org/content/aip/magazine/physicstoday/article/69/12/10.1063/PT.3.3397

We went from Sci ti SciFi. Maybe get back to topic.

Offline WarpTech

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See the attached for clarification. Note the force direction arrows in the bottom images that point to the end plate with the shortest 1/2 wave, that has the highest photon momentum & radiation pressure.

TT, you're showing data for Eagleworks' frustum with dielectric at small end and TE012 mode, where max E & H fields are located near small end.

Whereas zellerium, WarpTech and Star-Drive are discussing Eagleworks' frustum with dielectric at small end and TM212 mode, where max E & H fields are located near big end. Besides, in that particular mode only 10% of the RF energy resides in the PE discs.

Your "shorter vs longer 1/2 wave" conjecture may still apply, but the two field configurations are very different, and their max strength values are located opposite from each other.

We only have data for TE012 for both dielectric and non dielectric forces and direction.

It is which end has the shortest 1/2 that is of interest as the shortest 1/2 wave has the highest momentum and radiation pressure.

As Roger has shown, without dielectrics, as attached, the static force is generated small to big as Paul and I also measured and observed.

Any theory needs to be able to explain the force direction and why it swaps direction with and without dielectric when excited in the same mode.

I may be that where the highest energy density is located is not what is creating the measured static force with a direction big to small when a dielectric is at the small end.

Please note the measured force direction, big to small is the same for ALL the EW tests and seems to be mode independent.

The EW mode map I have seen has shown the TM212 dielectric frustum also has the shortest 1/2 wave at the small end, which is consistent with the measured force direction being big to small.

Zellerium's mode map in TM212 also shows the shortest 1/2 wave at the small end, which us consistent with the EW TM212 mode map.

TT,

For the NASA TE012 mode data, my theory did predict the reversed direction of force when the dielectric was added. However, the TM212 mode simulation that @zellerium just posted shows a different configuration of energy, wavelength and losses. IMO, the only issue is that I went by what was shown on the graphs as "Volume Loss Density", when I believe we should be looking at "Surface Loss Density", to have an accurate representation. Then it would be obvious that in the TM212 mode the majority of losses are at the big end, when the dielectric is present "shielding" the small end from those surface losses.

So one side has losses in the volume and the other has losses on the surface... But somehow the surface losses dissipate momentum differently than the volume losses?
If we wanted to optimize a cavity for thrust, would we want a balance between highest surface losses on one side, highest volume losses on the other side, and quality?

I think the volume losses could only model the solid dielectric, but could not model the losses of the skin effect in the copper, due to the planar nature of these losses. The surface losses look more accurate, but I think the total losses would be the combination of the two.

If we wanted to optimize cavity for thrust, we would want the highest surface losses at one end and the highest energy stored without losses, at the other end.  The magnetic flux stored in a cavity exerts pressure on the walls of the cavity. a voltage drop, resulting in losses in the walls of the cavity, is like poking a hole in it and letting the pressure out.

Offline Mark7777777

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FWIW, emdrives.com currently redirects to whatever is the last post on the last page of this new thread 9.

Offline Peter Lauwer

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I was surprised that I had never heard of this powerful accelerator. Then I realize I am not the only one who have not.

Long links break the page spanning on NSF. Use this link instead:

http://scitation.aip.org/content/aip/magazine/physicstoday/article/69/12/10.1063/PT.3.3397

We went from Sci ti SciFi. Maybe get back to topic.

We? This is only your 2nd posting.  ???
Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.   — Richard Feynman

Offline MrFrankenverse

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From Einstein we understand that an observer on a photon would see other photons, no matter their position, whether inside objects or elsewhere, traveling at the speed of light (discounting refraction for the moment). From inference then one might expect that when photons interact they do so with less reference to any previous interaction and more to their own vectors; the photons move energetically, without pushing against anything, until they actually push against something. In the context of these frustums and from Newton one must surely argue that any interaction at one end be canceled at the other, however, as Shawer points out, there's a difference in group velocity; there's an energy difference in the two standing waves which manifests as a vector of acceleration on the waveguide.

Offline InterestedEngineer

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Static force: Causes a scale or torsion pendulum to record a force acting against or with the scale or torsion pendulum. Equation F = (2 Qu Pwr Df) / c.

Dynamic force: Causes the free to accelerate acceleration of mass and is measured via F = A * M.

Can't measure both forces at the same time.

If I have an EmDrive sitting on a surface with significant friction (e.g. 1000 grit sandpaper), what happens when static force overcomes static friction and the EmDrive starts to move?  I think you indicated the dynamic force is in the other direction in a prior post.  Does the EmDrive reverse direction and try move the other way as soon as there's motion?  If so wouldn't the EmDrive+surface system be put back into the static friction regime when velocity relative to the surface momentarily reaches zero?  Seems like the EmDrive would effectively get nowhere on such a surface.

If my description is wrong, please supply a description of EmDrive behavior on a surface with significant friction.  The dynamic/static friction behavior of the movement on the surface is going to interact with your conjecture of static versus dynamic force, possibly in an interesting manner.

Offline X_RaY

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Regarding discussion about wave vectors and wave numbers, these are complex numbers*:
http://www.ece.rutgers.edu/~orfanidi/ewa/ch07.pdf
k=sqrt(kx^2+ky^2+kz^2)   [in cartesian coordinates]


*The radiation pressure is also related to complex expressions. If one only picks the z-component it leads to the incomplete viewpoint that there is a different radiation preasure at both end pates ::) hence the rest puts at the side wall and can also be separated into a r- and a z-component [terms in cylindrical coordinates].
« Last Edit: 12/01/2016 09:20 pm by X_RaY »

Offline M.LeBel

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See the attached for clarification. Note the force direction arrows in the bottom images that point to the end plate with the shortest 1/2 wave, that has the highest photon momentum & radiation pressure.

TT, you're showing data for Eagleworks' frustum with dielectric at small end and TE012 mode, where max E & H fields are located near small end.

Whereas zellerium, WarpTech and Star-Drive are discussing Eagleworks' frustum with dielectric at small end and TM212 mode, where max E & H fields are located near big end. Besides, in that particular mode only 10% of the RF energy resides in the PE discs.

Your "shorter vs longer 1/2 wave" conjecture may still apply, but the two field configurations are very different, and their max strength values are located opposite from each other.

We only have data for TE012 for both dielectric and non dielectric forces and direction.

It is which end has the shortest 1/2 that is of interest as the shortest 1/2 wave has the highest momentum and radiation pressure.

As Roger has shown, without dielectrics, as attached, the static force is generated small to big as Paul and I also measured and observed.

Any theory needs to be able to explain the force direction and why it swaps direction with and without dielectric when excited in the same mode.

I may be that where the highest energy density is located is not what is creating the measured static force with a direction big to small when a dielectric is at the small end.

Please note the measured force direction, big to small is the same for ALL the EW tests and seems to be mode independent.

The EW mode map I have seen has shown the TM212 dielectric frustum also has the shortest 1/2 wave at the small end, which is consistent with the measured force direction being big to small.

Zellerium's mode map in TM212 also shows the shortest 1/2 wave at the small end, which us consistent with the EW TM212 mode map.

TT,

For the NASA TE012 mode data, my theory did predict the reversed direction of force when the dielectric was added. However, the TM212 mode simulation that @zellerium just posted shows a different configuration of energy, wavelength and losses. IMO, the only issue is that I went by what was shown on the graphs as "Volume Loss Density", when I believe we should be looking at "Surface Loss Density", to have an accurate representation. Then it would be obvious that in the TM212 mode the majority of losses are at the big end, when the dielectric is present "shielding" the small end from those surface losses.

So one side has losses in the volume and the other has losses on the surface... But somehow the surface losses dissipate momentum differently than the volume losses?
If we wanted to optimize a cavity for thrust, would we want a balance between highest surface losses on one side, highest volume losses on the other side, and quality?

I think the volume losses could only model the solid dielectric, but could not model the losses of the skin effect in the copper, due to the planar nature of these losses. The surface losses look more accurate, but I think the total losses would be the combination of the two.

If we wanted to optimize cavity for thrust, we would want the highest surface losses at one end and the highest energy stored without losses, at the other end.  The magnetic flux stored in a cavity exerts pressure on the walls of the cavity. a voltage drop, resulting in losses in the walls of the cavity, is like poking a hole in it and letting the pressure out.

So,.... What?  An inside shiny metal surface for one half of the cavity, and a "thin" dielectric coating for the other half? Would that work?  A "thin" layered dielectric still reflecting the MW waves like interference based mirrors do... That wouldn't be thin  :)
That would be kind of like a reflection not based on induced E and B from free electron rich metal surface but on return capacitance of the surface... Am I making any sense?

   

Offline WarpTech

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I think the volume losses could only model the solid dielectric, but could not model the losses of the skin effect in the copper, due to the planar nature of these losses. The surface losses look more accurate, but I think the total losses would be the combination of the two.

If we wanted to optimize cavity for thrust, we would want the highest surface losses at one end and the highest energy stored without losses, at the other end.  The magnetic flux stored in a cavity exerts pressure on the walls of the cavity. a voltage drop, resulting in losses in the walls of the cavity, is like poking a hole in it and letting the pressure out.

So,.... What?  An inside shiny metal surface for one half of the cavity, and a "thin" dielectric coating for the other half? Would that work?  A "thin" layered dielectric still reflecting the MW waves like interference based mirrors do... That wouldn't be thin  :)
That would be kind of like a reflection not based on induced E and B from free electron rich metal surface but on return capacitance of the surface... Am I making any sense?


Not really. Where is the voltage drop, in the dielectric? Personally, I think it will do better without a dielectric. It might do better with nickel at one end, copper at the other end, but it will perform best with the largest amount of stored energy, exerting the maximum amount of pressure on the cavity.

Offline M.LeBel

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I think the volume losses could only model the solid dielectric, but could not model the losses of the skin effect in the copper, due to the planar nature of these losses. The surface losses look more accurate, but I think the total losses would be the combination of the two.

If we wanted to optimize cavity for thrust, we would want the highest surface losses at one end and the highest energy stored without losses, at the other end.  The magnetic flux stored in a cavity exerts pressure on the walls of the cavity. a voltage drop, resulting in losses in the walls of the cavity, is like poking a hole in it and letting the pressure out.

So,.... What?  An inside shiny metal surface for one half of the cavity, and a "thin" dielectric coating for the other half? Would that work?  A "thin" layered dielectric still reflecting the MW waves like interference based mirrors do... That wouldn't be thin  :)
That would be kind of like a reflection not based on induced E and B from free electron rich metal surface but on return capacitance of the surface... Am I making any sense?


Not really. Where is the voltage drop, in the dielectric? Personally, I think it will do better without a dielectric. It might do better with nickel at one end, copper at the other end, but it will perform best with the largest amount of stored energy, exerting the maximum amount of pressure on the cavity.

? A voltage drop is how you lose energy; voltage drop -  eddy current - etc. This is what you want at one end (metallic) of the cavity. We do have a voltage drop across the dielectric coatingt; metal surface behind on one side and MW on the other side, causing minimal charge movement ... essentially a variable polarization of the dielectric,
i.e. much much less loss of energy.... Better than nickel  ?

Offline rfmwguy

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I think the volume losses could only model the solid dielectric, but could not model the losses of the skin effect in the copper, due to the planar nature of these losses. The surface losses look more accurate, but I think the total losses would be the combination of the two.

If we wanted to optimize cavity for thrust, we would want the highest surface losses at one end and the highest energy stored without losses, at the other end.  The magnetic flux stored in a cavity exerts pressure on the walls of the cavity. a voltage drop, resulting in losses in the walls of the cavity, is like poking a hole in it and letting the pressure out.

So,.... What?  An inside shiny metal surface for one half of the cavity, and a "thin" dielectric coating for the other half? Would that work?  A "thin" layered dielectric still reflecting the MW waves like interference based mirrors do... That wouldn't be thin  :)
That would be kind of like a reflection not based on induced E and B from free electron rich metal surface but on return capacitance of the surface... Am I making any sense?


Not really. Where is the voltage drop, in the dielectric? Personally, I think it will do better without a dielectric. It might do better with nickel at one end, copper at the other end, but it will perform best with the largest amount of stored energy, exerting the maximum amount of pressure on the cavity.

? A voltage drop is how you lose energy; voltage drop -  eddy current - etc. This is what you want at one end (metallic) of the cavity. We do have a voltage drop across the dielectric coatingt; metal surface behind on one side and MW on the other side, causing minimal charge movement ... essentially a variable polarization of the dielectric,
i.e. much much less loss of energy.... Better than nickel  ?
You cannot use a dielectric insert without a trade-off. In this case, an insert will lower the Q of the cavity, effectively widening the 3dB BW of the return loss response. More testing will be required to determine if that tradeoff is worth it, or...someone will have to develop a bullet-proof theory that "inserts provide X so thrust can become Y". 

Offline WarpTech

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I think the volume losses could only model the solid dielectric, but could not model the losses of the skin effect in the copper, due to the planar nature of these losses. The surface losses look more accurate, but I think the total losses would be the combination of the two.

If we wanted to optimize cavity for thrust, we would want the highest surface losses at one end and the highest energy stored without losses, at the other end.  The magnetic flux stored in a cavity exerts pressure on the walls of the cavity. a voltage drop, resulting in losses in the walls of the cavity, is like poking a hole in it and letting the pressure out.

So,.... What?  An inside shiny metal surface for one half of the cavity, and a "thin" dielectric coating for the other half? Would that work?  A "thin" layered dielectric still reflecting the MW waves like interference based mirrors do... That wouldn't be thin  :)
That would be kind of like a reflection not based on induced E and B from free electron rich metal surface but on return capacitance of the surface... Am I making any sense?


Not really. Where is the voltage drop, in the dielectric? Personally, I think it will do better without a dielectric. It might do better with nickel at one end, copper at the other end, but it will perform best with the largest amount of stored energy, exerting the maximum amount of pressure on the cavity.

? A voltage drop is how you lose energy; voltage drop -  eddy current - etc. This is what you want at one end (metallic) of the cavity. We do have a voltage drop across the dielectric coatingt; metal surface behind on one side and MW on the other side, causing minimal charge movement ... essentially a variable polarization of the dielectric,
i.e. much much less loss of energy.... Better than nickel  ?

A voltage drop in the metal allows magnetic flux (and momentum) to escape the frustum. A dielectric inside does not. I realize that the voltage drop is a loss of power and will result in a lower Q, and there will be a compromise between higher Q vs higher divergence of the flux, but unless something is getting out, or at least out of the cavity and into the copper, it's not going to move. My theory is the only one here that is proposing something observable that can get out of the cavity. 

PS: I expect the nickel to be the higher losses and the copper to be lower loss. My expectation is, if you want the small end leading, then the small end and side walls should be low loss and the big end plate should be higher loss material. But not a lot higher loss, just enough to cause a gradient. It still requires a large Q to create any thrust.
« Last Edit: 12/01/2016 10:11 pm by WarpTech »

Offline rq3

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See the attached for clarification. Note the force direction arrows in the bottom images that point to the end plate with the shortest 1/2 wave, that has the highest photon momentum & radiation pressure.

TT, you're showing data for Eagleworks' frustum with dielectric at small end and TE012 mode, where max E & H fields are located near small end.

From your description, I envision a superconducting plate at the big end, with the interior of the silver plated copper frustum containing a polyethylene or polytetrafluorethylene hollow cone "wall liner", with wall thickness tapering from zero at the big end to maximum (an internal point) at the small end.

Whereas zellerium, WarpTech and Star-Drive are discussing Eagleworks' frustum with dielectric at small end and TM212 mode, where max E & H fields are located near big end. Besides, in that particular mode only 10% of the RF energy resides in the PE discs.

Your "shorter vs longer 1/2 wave" conjecture may still apply, but the two field configurations are very different, and their max strength values are located opposite from each other.

We only have data for TE012 for both dielectric and non dielectric forces and direction.

It is which end has the shortest 1/2 that is of interest as the shortest 1/2 wave has the highest momentum and radiation pressure.

As Roger has shown, without dielectrics, as attached, the static force is generated small to big as Paul and I also measured and observed.

Any theory needs to be able to explain the force direction and why it swaps direction with and without dielectric when excited in the same mode.

I may be that where the highest energy density is located is not what is creating the measured static force with a direction big to small when a dielectric is at the small end.

Please note the measured force direction, big to small is the same for ALL the EW tests and seems to be mode independent.

The EW mode map I have seen has shown the TM212 dielectric frustum also has the shortest 1/2 wave at the small end, which is consistent with the measured force direction being big to small.

Zellerium's mode map in TM212 also shows the shortest 1/2 wave at the small end, which us consistent with the EW TM212 mode map.

TT,

For the NASA TE012 mode data, my theory did predict the reversed direction of force when the dielectric was added. However, the TM212 mode simulation that @zellerium just posted shows a different configuration of energy, wavelength and losses. IMO, the only issue is that I went by what was shown on the graphs as "Volume Loss Density", when I believe we should be looking at "Surface Loss Density", to have an accurate representation. Then it would be obvious that in the TM212 mode the majority of losses are at the big end, when the dielectric is present "shielding" the small end from those surface losses.

So one side has losses in the volume and the other has losses on the surface... But somehow the surface losses dissipate momentum differently than the volume losses?
If we wanted to optimize a cavity for thrust, would we want a balance between highest surface losses on one side, highest volume losses on the other side, and quality?

I think the volume losses could only model the solid dielectric, but could not model the losses of the skin effect in the copper, due to the planar nature of these losses. The surface losses look more accurate, but I think the total losses would be the combination of the two.

If we wanted to optimize cavity for thrust, we would want the highest surface losses at one end and the highest energy stored without losses, at the other end.  The magnetic flux stored in a cavity exerts pressure on the walls of the cavity. a voltage drop, resulting in losses in the walls of the cavity, is like poking a hole in it and letting the pressure out.

Offline M.LeBel

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I think the volume losses could only model the solid dielectric, but could not model the losses of the skin effect in the copper, due to the planar nature of these losses. The surface losses look more accurate, but I think the total losses would be the combination of the two.

If we wanted to optimize cavity for thrust, we would want the highest surface losses at one end and the highest energy stored without losses, at the other end.  The magnetic flux stored in a cavity exerts pressure on the walls of the cavity. a voltage drop, resulting in losses in the walls of the cavity, is like poking a hole in it and letting the pressure out.

So,.... What?  An inside shiny metal surface for one half of the cavity, and a "thin" dielectric coating for the other half? Would that work?  A "thin" layered dielectric still reflecting the MW waves like interference based mirrors do... That wouldn't be thin  :)
That would be kind of like a reflection not based on induced E and B from free electron rich metal surface but on return capacitance of the surface... Am I making any sense?


Not really. Where is the voltage drop, in the dielectric? Personally, I think it will do better without a dielectric. It might do better with nickel at one end, copper at the other end, but it will perform best with the largest amount of stored energy, exerting the maximum amount of pressure on the cavity.

? A voltage drop is how you lose energy; voltage drop -  eddy current - etc. This is what you want at one end (metallic) of the cavity. We do have a voltage drop across the dielectric coatingt; metal surface behind on one side and MW on the other side, causing minimal charge movement ... essentially a variable polarization of the dielectric,
i.e. much much less loss of energy.... Better than nickel  ?

A voltage drop in the metal allows magnetic flux (and momentum) to escape the frustum. A dielectric inside does not. I realize that the voltage drop is a loss of power and will result in a lower Q, and there will be a compromise between higher Q vs higher divergence of the flux, but unless something is getting out, or at least out of the cavity and into the copper, it's not going to move. My theory is the only one here that is proposing something observable that can get out of the cavity. 

PS: I expect the nickel to be the higher losses and the copper to be lower loss. My expectation is, if you want the small end leading, then the small end and side walls should be low loss and the big end plate should be higher loss material. But not a lot higher loss, just enough to cause a gradient. It still requires a large Q to create any thrust.

I was not talking about a dielectric insert but rather a dielectric coating for one of the reflective end walls of the cavity. in order to minimize losses... at one end. But, it appears that microwave dielectric manipulation is done using meta-materials with macroscopic dielectric resonators structures... New, probably hard to get ...

https://arxiv.org/pdf/1605.07487v1.pdf

Offline WarpTech

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A voltage drop in the metal allows magnetic flux (and momentum) to escape the frustum. A dielectric inside does not. I realize that the voltage drop is a loss of power and will result in a lower Q, and there will be a compromise between higher Q vs higher divergence of the flux, but unless something is getting out, or at least out of the cavity and into the copper, it's not going to move. My theory is the only one here that is proposing something observable that can get out of the cavity. 

PS: I expect the nickel to be the higher losses and the copper to be lower loss. My expectation is, if you want the small end leading, then the small end and side walls should be low loss and the big end plate should be higher loss material. But not a lot higher loss, just enough to cause a gradient. It still requires a large Q to create any thrust.

I was not talking about a dielectric insert but rather a dielectric coating for one of the reflective end walls of the cavity. in order to minimize losses... at one end. But, it appears that microwave dielectric manipulation is done using meta-materials with macroscopic dielectric resonators structures... New, probably hard to get ...

https://arxiv.org/pdf/1605.07487v1.pdf

I think the dielectric insert in EW TM212 mode test is doing just that, but I also think a good copper conductor with cooling would work better. They used FR4 1oz copper board on both ends. a 1oz copper platting, per my own experience, is very lossy. It doesn't take heat well. The dielectric is keeping it cool.
« Last Edit: 12/01/2016 11:02 pm by WarpTech »

Offline CraigPichach

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So.. my assumptions were incorrect.

Here is a public link to commercially available magnetrons; note that you have ranges of powers available at various frequencies. These are generally due to practical limitations.

 http://www2.l-3com.com/edd/products/r_magnetrons_s-band.htm

Looking at this you end up with one major question - is it better to do a >MW test for microseconds vs. a 100kW test over seconds.

My initial thought is 100kW sustained is easier to measure; unsure which has the advantage on cooling (at MW that’s a lot of juice where you prob having a cooling system either way or can we make the test short enough that air cooling is satisfactory). I think best plan is thrusting down into a scale, just to work out the cooling that we aren’t worrying about evaporation. Would be nice if we generated enough thrust that it offset any of that.

Paul March's simulation results seemed to indicate that the thrust happens very fast that we can use a short pulse to generate thrust. On a fast time scale could pulse the magnetron at different repetition rates to try to separate out the thrust from other noise like average heating effects however long pulse should be easier to measure but need to worry about robust cooling system.

Thoughts??


Offline R.W. Keyes

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I recall this issue being raised before, but it was a while ago and the situation may have changed.  Is it reasonably possible to 3D print an emdrive, or a major portion of it? I mean direct fab and not making a wax model, a mold, and then casting it.

I am not asking if the typical $800 hobbyist unit can do this, though it would be interesting if such a device could. I am talking about the big expensive machines from places like Stratasys...can they do this? If so, does it economically make sense?

The reason I ask is because I have tax reasons to quickly spend money (six figures) on industrial equipment (before the end of the year). If buying a high-end 3d printer and using it to make some money by producing emdrive prototypes for people has a chance of being economically feasible, I'd like to know and get started ASAP.

Offline toloverufan

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I know there's been some talk about the drive pushing against some quantum vacuum, but maybe something like this is what's happening? Not sure if it's some separate phenomenon, or just a bigger version of the same thing, but it seems like something to add.

Offline WarpTech

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I recall this issue being raised before, but it was a while ago and the situation may have changed.  Is it reasonably possible to 3D print an emdrive, or a major portion of it? I mean direct fab and not making a wax model, a mold, and then casting it.

I am not asking if the typical $800 hobbyist unit can do this, though it would be interesting if such a device could. I am talking about the big expensive machines from places like Stratasys...can they do this? If so, does it economically make sense?

The reason I ask is because I have tax reasons to quickly spend money (six figures) on industrial equipment (before the end of the year). If buying a high-end 3d printer and using it to make some money by producing emdrive prototypes for people has a chance of being economically feasible, I'd like to know and get started ASAP.

I think the casting places typically have their own 3d printer. All you do is provide the CAD file for the part. They will update it to work with their type of casting, and the type of finish required, and give you a chance to approve it before the part is cast. It's not that expensive, nowhere near six figures!  :o 
« Last Edit: 12/02/2016 12:59 am by WarpTech »

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