EM Drive

Point out news stories, on the net or in mainstream media, related to polywell fusion.

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Skipjack
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Re: EM Drive

Post by Skipjack »

I have not seen Shawyers test setup, but Fettas test setup does not attach the powersupply to the thruster but brings in power from an external source. That is IMHO a flaw in the experimental setup.

birchoff
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Re: EM Drive

Post by birchoff »

Skipjack wrote:I have not seen Shawyers test setup, but Fettas test setup does not attach the powersupply to the thruster but brings in power from an external source. That is IMHO a flaw in the experimental setup.
I meant to ask you this before, why could the powersupply not being on the thrust measurement device be a problem?

tokamac
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Re: EM Drive

Post by tokamac »

Skipjack wrote:I have not seen Shawyers test setup, but Fettas test setup does not attach the powersupply to the thruster but brings in power from an external source. That is IMHO a flaw in the experimental setup.
FYI in October 2006 Shawyer tested a resonant cavity on a rotating rig, the whole system weighing 100 kg, comprising the thruster, the generator (magnetron), its cooling system and the structural frame, mounted on a beam supported on a low-friction air bearing. The device reportedly consumed 300 W of power and produced a force of 96.1 mN, a maximum speed of 2 cm/s over 185 cm. Shawyer stated the engine starts to accelerate only when the magnetron frequency locks to the resonant frequency of the thruster, following an initial warm up period, which is interesting regarding the prevention of any spurious effect.

See http://www.wired.com/2008/10/video-impossibl/ for more explanation and a video of this device in action.

birchoff
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Re: EM Drive

Post by birchoff »

tokamac wrote:
Skipjack wrote:I have not seen Shawyers test setup, but Fettas test setup does not attach the powersupply to the thruster but brings in power from an external source. That is IMHO a flaw in the experimental setup.
FYI in October 2006 Shawyer tested a resonant cavity on a rotating rig, the whole system weighing 100 kg, comprising the thruster, the generator (magnetron), its cooling system and the structural frame, mounted on a beam supported on a low-friction air bearing. The device reportedly consumed 300 W of power and produced a force of 96.1 mN, a maximum speed of 2 cm/s over 185 cm. Shawyer stated the engine starts to accelerate only when the magnetron frequency locks to the resonant frequency of the thruster, following an initial warm up period, which is interesting regarding the prevention of any spurious effect.

See http://www.wired.com/2008/10/video-impossibl/ for more explanation and a video of this device in action.
Well your answer is right if SkipJack is referring to the Magnetron when he says powersupply. The question is what does he mean when he says powersupply. Is he referring to the Source of Electrical energy, or the Source of Microwave Energy. If it is the former then they maybe a problem but I would like to know why that would be a problem in the first place. If it is the later then its a non issue since the Magnetron is the source of the Microwave Energy as I understand Shawyers setup and as tokamac said this was on the airbearing.

hanelyp
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Re: EM Drive

Post by hanelyp »

birchoff wrote:I meant to ask you this before, why could the powersupply not being on the thrust measurement device be a problem?
Looking at a certain unrelated photon thruster may give some insight.

A solar sail give a small thrust relative to the optical power reflected. But if photons can be reflected back and forth between a pair of mirrors thrust increases by optical cavity Q.

Similarly, microwaves traveling through a transmission line carry momentum, increased by reflection at both ends of the system.
The daylight is uncomfortably bright for eyes so long in the dark.

Skipjack
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Joined: Sun Sep 28, 2008 2:29 pm

Re: EM Drive

Post by Skipjack »

birchoff wrote:
tokamac wrote:
Skipjack wrote:I have not seen Shawyers test setup, but Fettas test setup does not attach the powersupply to the thruster but brings in power from an external source. That is IMHO a flaw in the experimental setup.
FYI in October 2006 Shawyer tested a resonant cavity on a rotating rig, the whole system weighing 100 kg, comprising the thruster, the generator (magnetron), its cooling system and the structural frame, mounted on a beam supported on a low-friction air bearing. The device reportedly consumed 300 W of power and produced a force of 96.1 mN, a maximum speed of 2 cm/s over 185 cm. Shawyer stated the engine starts to accelerate only when the magnetron frequency locks to the resonant frequency of the thruster, following an initial warm up period, which is interesting regarding the prevention of any spurious effect.

See http://www.wired.com/2008/10/video-impossibl/ for more explanation and a video of this device in action.
Well your answer is right if SkipJack is referring to the Magnetron when he says powersupply. The question is what does he mean when he says powersupply. Is he referring to the Source of Electrical energy, or the Source of Microwave Energy. If it is the former then they maybe a problem but I would like to know why that would be a problem in the first place. If it is the later then its a non issue since the Magnetron is the source of the Microwave Energy as I understand Shawyers setup and as tokamac said this was on the airbearing.
I am referring to the source of the electricity powering the device. It would have to be a battery or capacitor on the thruster, not a cable plugged into a power outlet.

GIThruster
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Re: EM Drive

Post by GIThruster »

birchoff wrote:I meant to ask you this before, why could the powersupply not being on the thrust measurement device be a problem?
It's very common for engineers who are unfamiliar with a test setup to hypothesize the ridiculous, such as that the power supply being run off the balance causes some sort of spurious source acting as a thrust trace. Fact is, this is always simple ignorance on the part of the engineer making such an hypothesis. There are many, many ways to test for these kinds of spurious influences, all of which need to be pursued, so questions born of ignorance like this one, are really just examples of ignorance and should be ignored.

I can promise you, Paul March is not going to make the kind of mistake necessary to commit to such an obvious blunder. I can also promise you, there will be no end to the self appointed critics acting as if they have a clue, when they know they are completely ignorant of the experimental setup, and those critics will embarrass themselves in more ways than one can count on the first opportunity to do so.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

Skipjack
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Re: EM Drive

Post by Skipjack »

GIThruster wrote:
birchoff wrote:I meant to ask you this before, why could the powersupply not being on the thrust measurement device be a problem?
It's very common for engineers who are unfamiliar with a test setup to hypothesize the ridiculous, such as that the power supply being run off the balance causes some sort of spurious source acting as a thrust trace. Fact is, this is always simple ignorance on the part of the engineer making such an hypothesis. There are many, many ways to test for these kinds of spurious influences, all of which need to be pursued, so questions born of ignorance like this one, are really just examples of ignorance and should be ignored.

I can promise you, Paul March is not going to make the kind of mistake necessary to commit to such an obvious blunder. I can also promise you, there will be no end to the self appointed critics acting as if they have a clue, when they know they are completely ignorant of the experimental setup, and those critics will embarrass themselves in more ways than one can count on the first opportunity to do so.
Don't get me wrong, I don't have a problem with Woodwards theory and his work, but I have a problem with this experimental setup, which has obvious flaws.

tokamac
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Re: EM Drive

Post by tokamac »

Skipjack wrote:Don't get me wrong, I don't have a problem with Woodwards theory and his work, but I have a problem with this experimental setup, which has obvious flaws.
Where did you see in GIThruster's comment a reference to Woodward's theory (or his experimental setup)? He was talking about any experiment involving thrust detection for any engine on a test bed.

The power source could be onboard or external, this wouldn't prevent spurious effects to show up. Those spurious causes involve device unbalance; current leakage, electrostatic spatial charge, thermal gradient, ion wind (that interacts with ambient air); EM coupling with the cables and structural frame, mechanical, inductive and magnetic resonance… That's why scientists carefully test their apparatus to detect any force, first without the thruster on the setup, then with the thruster present but in a "null" configuration, then with the thruster active but in different orientations.

Once you have detected a repeatable spurious force on your setup (you want it to be ideally undetectable relatively to the balance resolution, or as small as possible regarding the thrust magnitude produced by the engine you're testing) you subtract this force from the force measured during the engine tests. This is why the resulting force is called the "net thrust". Then you repeat the experiment several times, and you get a "mean net thrust" for each direction.

In the NASA experiment, nullify the drives consisted of connecting a 50 ohm load, that prevented them from generating thrust. The team then measured the EM coupling with the whole apparatus, and they detected a spurious force at 9.6 micronewtons. This force was subtracted from the thrusts produced by the test articles (that were twice to ten times the spurious force level), which gave net thrusts. As a reminder Eagleworks' low-thrust torsion pendulum resolution is as low as 1 micronewton. That seems ok to me.

A common spurious cause involves interaction of the test apparatus (current leakage and/or thermal effect) with ambient air. Especially if the device is asymmetrically shaped or has parts hotter than others, like the EmDrive. That is why this engine absolutely needs to be tested in a hard vacuum (yet to be done).

Skipjack
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Re: EM Drive

Post by Skipjack »

tokamac wrote:
Skipjack wrote:Don't get me wrong, I don't have a problem with Woodwards theory and his work, but I have a problem with this experimental setup, which has obvious flaws.
Where did you see in GIThruster's comment a reference to Woodward's theory (or his experimental setup)? He was talking about any experiment involving thrust detection for any engine on a test bed.
Because he usually is talking about that opposed to Shawyers and Whites devices.
tokamac wrote: The power source could be onboard or external, this wouldn't prevent spurious effects to show up. Those spurious causes involve device unbalance; current leakage, electrostatic spatial charge, thermal gradient, ion wind (that interacts with ambient air); EM coupling with the cables and structural frame, mechanical, inductive and magnetic resonance…
Which is what I was trying to convey. There are other issues with this as well.

Aero
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Location: 92111

Re: EM Drive

Post by Aero »

I read the abstract linked in the OP on some post either here or on NSF. Is there a complete report on the experiment by White, et.al available somewhere?

And by the way, microwave oven frequency is chosen at the water line, so the microwave energy will excite the water in the food. Is the frequency White is using chosen to for the "virtual particle line?" If not, why not, and if so, how does he know what it is?
Aero

hudson
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Joined: Sun May 26, 2013 3:21 pm

Re: EM Drive

Post by hudson »

I found this full text posted from a different page
http://rghost.net/57230791

birchoff
Posts: 200
Joined: Sun Jul 27, 2014 7:11 pm

Re: EM Drive

Post by birchoff »

GIThruster wrote:
birchoff wrote:I meant to ask you this before, why could the powersupply not being on the thrust measurement device be a problem?
It's very common for engineers who are unfamiliar with a test setup to hypothesize the ridiculous, such as that the power supply being run off the balance causes some sort of spurious source acting as a thrust trace. Fact is, this is always simple ignorance on the part of the engineer making such an hypothesis. There are many, many ways to test for these kinds of spurious influences, all of which need to be pursued, so questions born of ignorance like this one, are really just examples of ignorance and should be ignored.

I can promise you, Paul March is not going to make the kind of mistake necessary to commit to such an obvious blunder. I can also promise you, there will be no end to the self appointed critics acting as if they have a clue, when they know they are completely ignorant of the experimental setup, and those critics will embarrass themselves in more ways than one can count on the first opportunity to do so.
So if I am understanding you your saying the issues that could be caused by leaving the source of electrical power outside of the measurement device could cause problems. However, a skilled experimenter would be aware of the issues that could arise and counter them with no need to actually include the electrical power supply. However, doing such a thing is a nice way to deter ignorant engineers from calling out issues that actually do not exist? Is this a correct interpretation of what you said?

birchoff
Posts: 200
Joined: Sun Jul 27, 2014 7:11 pm

Re: EM Drive

Post by birchoff »

Skipjack wrote:
GIThruster wrote:
birchoff wrote:I meant to ask you this before, why could the powersupply not being on the thrust measurement device be a problem?
It's very common for engineers who are unfamiliar with a test setup to hypothesize the ridiculous, such as that the power supply being run off the balance causes some sort of spurious source acting as a thrust trace. Fact is, this is always simple ignorance on the part of the engineer making such an hypothesis. There are many, many ways to test for these kinds of spurious influences, all of which need to be pursued, so questions born of ignorance like this one, are really just examples of ignorance and should be ignored.

I can promise you, Paul March is not going to make the kind of mistake necessary to commit to such an obvious blunder. I can also promise you, there will be no end to the self appointed critics acting as if they have a clue, when they know they are completely ignorant of the experimental setup, and those critics will embarrass themselves in more ways than one can count on the first opportunity to do so.
Don't get me wrong, I don't have a problem with Woodwards theory and his work, but I have a problem with this experimental setup, which has obvious flaws.
So two of the issues I can infer from your previous comments are
  • Apparently not tested in Hard vacuum environment
    Electrical power supply apparently outside of thrust measurement device
Are there others?

birchoff
Posts: 200
Joined: Sun Jul 27, 2014 7:11 pm

Re: EM Drive

Post by birchoff »

tokamac wrote: The power source could be onboard or external, this wouldn't prevent spurious effects to show up. Those spurious causes involve device unbalance; current leakage, electrostatic spatial charge, thermal gradient, ion wind (that interacts with ambient air); EM coupling with the cables and structural frame, mechanical, inductive and magnetic resonance…
Which is what I was trying to convey. There are other issues with this as well.[/quote]


Ok I think the problem here is that at the very least I do not understand what your trying to say. From my perspective tokomac is saying that irrespective of where you put the electrical power source. you can get anyone of the following spurious effects
  • current leakage
    electrostatic spatial charge
    thermal gradient
    ion wind (that interacts with ambient air)
    EM coupling with the cables and structural frame
    mechanical resonance
    inductive resonance
    magnetic resonance
It seems like the experimenters attempted to control for some of these issues listed above not all as tokomac describes, hence the need for more experiments, that include the additional controls.

That said is there something else here both tokomac and I are not aware of outside of this list. If so please state it plainly so that when the next set of results are published we have a clearly defined benchmark to judge it from.

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