Author Topic: EM Drive Developments Thread 1  (Read 764366 times)

Offline ChrisWilson68

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Re: EM Drive Developments
« Reply #120 on: 08/02/2014 11:01 PM »
Real advances in science come from careful experimentation and analysis, the discovery of anomalous results, and the advancement of theories to explain those results, without any particular engineering goal in mind.
Which is exactly what the authors are trying to do.

You're missing my point.  Looking around randomly for anomalies isn't a very good strategy.  Neither is designing a device based on a misunderstanding of known physics to see if it happens to work.  There are better places to choose to look for anomalies.

You also missed the "careful" point.  Sonny White and friends have a long history of claims based on experimental setups that have been criticized as poorly controlled.

Offline ChrisWilson68

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Re: EM Drive Developments
« Reply #121 on: 08/02/2014 11:05 PM »

Real advances in science come from careful experimentation and analysis, the discovery of anomalous results, and the advancement of theories to explain those results, without any particular engineering goal in mind.
Which is exactly what the authors are trying to do.

That point seems to have escaped the OP.

The point that escaped you is the part where I said "without any particular engineering goal in mind".

Having a goal of making a reactionless drive and then looking for physics to make it work is backwards.  That's not how discoveries in physics are made.  They are made by not having any preconceived ideas about applications.

Offline frobnicat

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Re: EM Drive Developments
« Reply #122 on: 08/02/2014 11:14 PM »
Is there theoretical limits to how high the Q factor of a resonant cavity can go ? If constant thrust necessitates constant power above some threshold, then "propellentless propulsion" doesn't really escape the rocket equation because of mass energy equivalence : all the energy put into the engine must come at the price of "burned" mass. A photon engine is a well understood example of changing "object's momentum without expelling mass" as photons have no rest mass, but they require energy (burning fuel mass) to be created... How the proposal would be better than a photon rocket ?
If the hypothetical thrust effect is limited to be small enough compared to the required power, then even a constant thrust (not depending on speed) at constant power doesn't imply "free energy" as the ship would bleed enough mass flow in the conversion to the required power to maybe equal but not beat a perfect physically respectable photon rocket. Granted, at slower speeds the ability to efficiently "push" on space or whatever without expelling reaction mass would be convenient as a few percent of mass of energy fuel only is lost in the process and the (non relativistic part of) rocket equation kind of vanishes...

Offline IslandPlaya

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Re: EM Drive Developments
« Reply #123 on: 08/02/2014 11:25 PM »
As far as I know there are no theoretical limits on the Q factor in a superconducting cavity.
Practical limits is another thing entirely of course...

Offline IslandPlaya

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Re: EM Drive Developments
« Reply #124 on: 08/02/2014 11:33 PM »
I have not seen 'free energy' mentioned for quite a few posts now.
Thank you all for your reasoned ideas. Much to sleep on...
Another thought, although it may seem to make me more of kook than some people already think...
If this effect was real, do you think we would hear anything true about it? The military would be all over it like a rash...
Just a thought.

Offline Silversheep2011

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Re: EM Drive Developments
« Reply #125 on: 08/02/2014 11:35 PM »
They are made by not having any preconceived ideas about applications.

How do you look for a new law in physics?

A friend shared this with me. It makes the point well.
and Visa versa

« Last Edit: 08/02/2014 11:38 PM by Silversheep2011 »

Offline IslandPlaya

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Re: EM Drive Developments
« Reply #126 on: 08/02/2014 11:43 PM »
Having a goal of making a reactionless rocket drive and then looking for physics to make it work is backwards.  That's not how discoveries in physics are made.  They are made by not having any preconceived ideas about applications.
Strikethru mine.
Do you see how silly this sounds?

Offline CW

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Re: EM Drive Developments
« Reply #127 on: 08/02/2014 11:44 PM »
If I'm not mistaken, the magnetic field strength that a superconductor is subjected to externally, has a well-defined upper limit, before superconductivity breaks down. So I'm a bit worried that there's only a certain amount of photons that can be within such a cavity at any given instant in time, due to the magnetic field component of the photons possibly impinging on the surface of the superconductor at the same time. Or perhaps that is no problem at all, maybe someone can elaborate on behavior of superconductor and photon interaction.

IMHO the charm of a working EM drive would be that, in the best case, it would become possible to create ultra-high Q cavities (minimal losses), pump them full of photons and let the device counteract 1:1 Earth's gravity for all kinds of transportation purposes with small energy requirements. I'm not so sure if space travel were the most prominent application of such a device. But who knows.
Reality is weirder than fiction

Offline ChrisWilson68

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Re: EM Drive Developments
« Reply #128 on: 08/03/2014 12:44 AM »
Having a goal of making a reactionless rocket drive and then looking for physics to make it work is backwards.  That's not how discoveries in physics are made.  They are made by not having any preconceived ideas about applications.
Strikethru mine.
Do you see how silly this sounds?

No, it's not silly when you replace the word "reactionless" with "rocket".

You are still missing my point.  My point is that physics and engineering are two different things.  When you go to do engineering, you come up with a device you would like to create, and you use known physics to create it.  You you do physics, you don't start with an engineering problem you'd like to solve, you start by looking for what part of the experimental envelope of the behavior of the world hasn't been adequately explored, and you start exploring it.  Trying to find new physics by doing engineering is foolish.

Physics is about discovering what the truth of the universe as it already exists is.  Engineering is about using the knowledge from physics to make changes in the universe.  The approaches to the two subjects that yield best results are very different.

Offline mlindner

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Re: EM Drive Developments
« Reply #129 on: 08/03/2014 01:54 AM »
The fact that this article is even being considered by NSF members has me seriously worried about the future of American technological might.

Have we really gotten to the point that something akin to free energy generation that quackpots trot around on youtube with has gotten smart people this confused?

This technology has fraud written all over it. The creator will profit monetarily if it succeeds. He only agrees to let you test it if you agree that his theories are correct. The test device itself was built by the creator. The NEGATIVE test device showed positive results, thus completely invalidating the test. The effects of atmosphere were not removed from the testing chamber. The effects of outgassing and mass loss were not accounted for. The AIAA paper in question only has two references, one to the creator's website and one to the other faulty Chinese test.

This is terrible all over. The world is being given the runaround by this guy.

http://arstechnica.com/science/2014/08/dont-buy-stock-in-impossible-space-drives-just-yet/

Direct link to the pdf (this won't work unless your univeristy/company has a subscription). http://arc.aiaa.org/doi/pdf/10.2514/6.2014-4029
« Last Edit: 08/03/2014 01:56 AM by mlindner »
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Offline mlindner

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Re: EM Drive Developments
« Reply #130 on: 08/03/2014 02:09 AM »
This is even more exciting than the warp drive research, since if it pans out we could have practical applications almost immediately (i.e., within a couple of years).  No more gravity assists would ever be necessary again.
And free energy.

(*) Propellantless propulsion lets you increase velocity proportional to the energy you put in.
(*) Classical physics lets you extract energy proportional to the velocity squared.

Wow that's a perfect way to debunk this. I was looking for something short and sweet like this.
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Offline cuddihy

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Re: EM Drive Developments
« Reply #131 on: 08/03/2014 02:55 AM »
This is even more exciting than the warp drive research, since if it pans out we could have practical applications almost immediately (i.e., within a couple of years).  No more gravity assists would ever be necessary again.
And free energy.

(*) Propellantless propulsion lets you increase velocity proportional to the energy you put in.
(*) Classical physics lets you extract energy proportional to the velocity squared.

Wow that's a perfect way to debunk this. I was looking for something short and sweet like this.

[facepalm]
Brevity is the soul of wit...and a close companion of confirmation bias, apparently.

Offline Stormbringer

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Re: EM Drive Developments
« Reply #132 on: 08/03/2014 03:22 AM »
This is even more exciting than the warp drive research, since if it pans out we could have practical applications almost immediately (i.e., within a couple of years).  No more gravity assists would ever be necessary again.
And free energy.

(*) Propellantless propulsion lets you increase velocity proportional to the energy you put in.
(*) Classical physics lets you extract energy proportional to the velocity squared.

Wow that's a perfect way to debunk this. I was looking for something short and sweet like this.

yesh. you wouldn't want to try to find out where the unexpected energy comes from or something all scientific like. here is the issue with that. random debunking is bunkum. whatever the root cause of a phenomenon whether valid or not you just say it's swamp gas. it does not really explain what happened. it's every bit as much bunk as claiming it's Klaatu.
When antigravity is outlawed only outlaws will have antigravity.

Offline mlindner

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Re: EM Drive Developments
« Reply #133 on: 08/03/2014 03:31 AM »
This is even more exciting than the warp drive research, since if it pans out we could have practical applications almost immediately (i.e., within a couple of years).  No more gravity assists would ever be necessary again.
And free energy.

(*) Propellantless propulsion lets you increase velocity proportional to the energy you put in.
(*) Classical physics lets you extract energy proportional to the velocity squared.

Wow that's a perfect way to debunk this. I was looking for something short and sweet like this.

yesh. you wouldn't want to try to find out where the unexpected energy comes from or something all scientific like. here is the issue with that. random debunking is bunkum. whatever the root cause of a phenomenon whether valid or not you just say it's swamp gas. it does not really explain what happened. it's every bit as much bunk as claiming it's Klaatu.

I'm all for using science to attempt to validate the claims. See my previous post. I want to see a proper experiment done with a proper negative test that demonstrates non-action and a proper test that accounts for variables of mass loss from evaporation/outgassing and proper testing in a vacuum to cancel out effects of movements of the atmosphere. I'll not believe an ounce of this until we get those minimum of tests done. After that some peer verification and tests by non-interested parties (namely parties that won't make money from the success) would be good as well.

I was mainly looking for a short description of a major issue with the experiment that I can feed to people to prompt them to engage their brains for a minute rather than shoveling the bull**** down their throats without thinking. After that some discussion can be sparked to realize the issues at hand.
« Last Edit: 08/03/2014 03:32 AM by mlindner »
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Offline KelvinZero

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Re: EM Drive Developments
« Reply #134 on: 08/03/2014 04:10 AM »
I have not seen 'free energy' mentioned for quite a few posts now.
Yeah.. I was thinking it isn't really appropriate to keep explaining this repeatedly in specific versions propellantless thrust threads. It does sort of derail the thread, which should only concern it self with explaining how it works around this particular well known issue. But everyone should understand what the issue is.

I liked your CMB suggestion, because then we can at least discuss how it behaves in particular circumstances. This is hugely powerful. The moment you start looking at a useful description of how it behaves whole new unexpected behavior can be discovered, such as extracting energy from the difference in velocity of the solar system and the CMB frame.. the existence of which still boggles my mind a bit.

If the theory is correct yet is not obvious to the thousands of physicists out there who are brighter than I, then obviously it will be beyond my understanding. I would just like to understand the claim to the level of a science fiction writer, so I could describe what it actually means to my fledgling galactic citizen.

I think rather than repeating these over and over, we should have a general thread and just refer to it. Im hoping other people will add their favorite paradox examples also.
..General explanation here...
Everyone should understand the issue, and then threads like this can just focus on how this version claims to get around it.
« Last Edit: 08/03/2014 05:16 AM by KelvinZero »

Offline Stormbringer

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Re: EM Drive Developments
« Reply #135 on: 08/03/2014 04:38 AM »


I was mainly looking for a short description of a major issue with the experiment that I can feed to people to prompt them to engage their brains for a minute rather than shoveling the bull**** down their throats without thinking. After that some discussion can be sparked to realize the issues at hand.

i think there are two major issues.

1. the signal is very small. this makes it easy for uncontrolled for unanticipated spurious signals to get in there. critic can claim this is what caused it all day long. it's hard to disprove.

2. in this experiment it appears the control test article got the same signal. I do not think this is as damning as it could be because of the signals found by other researchers with (similar devices of differing design details.)  E.G. Dr Woodward's design is a solid state peizoelectric stack. he gets a thrust signal. Dr White has a capacitor and coil ring and gets thrust signals. the Egyptian girl uses a moving casimir mirror and gets a thrust signal. The Chinese use Shayer's design as a starting point and get a much stronger thrust signal than he did or NASA testing got.
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Offline FlyingMoose

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Re: EM Drive Developments
« Reply #136 on: 08/03/2014 04:43 AM »
The EmDrive and White's theories are the opposite -- they put the theory first and then go looking for evidence afterwards.  In both cases, the theories claim to be consequences of existing theories in physics, but reputable physicists say that in fact they come from misunderstandings of current theories.

That is incorrect.  This discovery came about because Shawyer was trying to explain the thrust generated by the microwave transmitters on satellites which exceeded what was expected and required additional fuel to correct.

Offline FlyingMoose

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Re: EM Drive Developments
« Reply #137 on: 08/03/2014 05:46 AM »
(*) Propellantless propulsion lets you increase velocity proportional to the energy you put in.

How is this any different from an ion thruster?

If you do one burn to bring a satellite up to 10 m/s, and then another with the same energy that brings it to 20 m/s, you have the same phenomenon.  In the second burn, you get more kinetic energy than in the first burn, even though your thruster expended the same amount of energy.

Offline ChrisWilson68

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Re: EM Drive Developments
« Reply #138 on: 08/03/2014 05:52 AM »
(*) Propellantless propulsion lets you increase velocity proportional to the energy you put in.

How is this any different from an ion thruster?

If you do one burn to bring a satellite up to 10 m/s, and then another with the same energy that brings it to 20 m/s, you have the same phenomenon.  In the second burn, you get more kinetic energy than in the first burn, even though your thruster expended the same amount of energy.

The difference is that with the ion thruster you had to put in more energy for the first 10 m/s because you had to accelerate both the satellite and the propellant you're going to use for the second burn.  You can think of it as the propellant for the second burn already having a bunch of kinetic energy from the first burn and you're using both that kinetic energy already in the prop plus the electric energy of the thruster to get the second 10 m/s of delta-v.

Offline MP99

Re: EM Drive Developments
« Reply #139 on: 08/03/2014 06:34 AM »


What this thesis ignores is that none of these theories extend how their devices would function as velocity increases.

[quote name="RonM" post=1237898 timestamp=1406988473]propulsive momentum transfer via the quantum vacuum virtual plasma." [/quote]

Surely, interactions with the quantum vacuum should be unaffected by your velocity - you can always see a "version" of the vacuum as if you are currently at rest?

Cheers, Martin

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