Em drives

[Urwumpe]

...And?

Can you even slightly imagine how many influences such an experiment setup can have, if you are not operating it in a vacuum?

 

[MaverickSawyer]

Well, if your engine is supposed to be run in vacuum, why the hell are you testing at atmospheric pressure anyways? :shrug:

 

[kamaz]

Can you even slightly imagine how many influences such an experiment setup can have, if you are not operating it in a vacuum?

Sure I can. All I'm saying is that the proposed explanation does not fit the data.

 

[Urwumpe]

Sure I can. All I'm saying is that the proposed explanation does not fit the data.

That is what we are all saying here. :lol:

 

[kamaz]

Well, to be honest, there is an explanation which fits the data, but accepting it leads you very deep down the rabbit hole... Or rather a certain crater in New Mexico.

Rabbit holes are dangerous places... People avoid them for a good reason. It's said they can take away your sanity.

 

[Urwumpe]

Well, to be honest, there is an explanation which fits the data, but accepting it leads you very deep down the rabbit hole... Or rather a certain crater in New Mexico.

Rabbit holes are dangerous places... People avoid them for a good reason. It's said they can take away your sanity.

There is a much simpler explanation and which can also easily fit the data, which does not require you to believe in Cheshire cats, invisible pink unicorns or Quantum Vacuum Plasma.

If they did decide to use ambient pressure for being able to manually adjust the resonance frequency of the "thruster" often during the experiment - how long do you think did they let the test chamber rest before measuring? And how long did they actually measure?

With such a torque balance, you could even measure everything if you are not carefully neutralizing everything BUT The thing you want to measure. Just turning something on and measuring a difference does not work out.

 

[kamaz]

This kind of error will show up as random noise.

Better explain this: why the force measured with the test article is 5x larger then the force measured with a load resistor mounted on the same torsion pendulum, all that while the measured force values are repeatable within 25%?

 

[Urwumpe]

This kind of error will show up as random noise.

Would it? Really?

Read the abstract carefully: they did all their measurements in just two days there, 13 test runs, including modifications between the runs, in 20 hours (including scientific overtime)

Better explain this: why the force measured with the test article is 5x larger then the force measured with a load resistor mounted on the same torsion pendulum, all that while the measured force values are repeatable within 25%?

For that, simply look up, what a RF load resistor actually is, especially compared to the feed horn designs used as thruster test articles there.

Also, please pay attention that their measurements already varied depending on the direction in which the antenna was pointing. That alone suggests that there was an external influence in the test system.

 

[kamaz]

What is your proposed explanation?

 

[Urwumpe]

What is your proposed explanation?

Simple electromagnetic interaction between conductive waveguide and other metal parts in the vicinity. The test chamber has not been exactly large and filled with other metal parts.

If you look at the unslotted test article, you see a simple feed horn antenna there - the higher effectivity in the experiment could be simply because it is simply the better feedhorn compared to the slotted variant, which reminds me first of all on multi-hole filters.

[ame="http://en.wikipedia.org/wiki/Waveguide_filter"]Waveguide filter - Wikipedia, the free encyclopedia[/ame]

I would not even be surprised, if the difference in measured force is also the difference in antenna effectivity.

 

[MattBaker]

Well, if your engine is supposed to be run in vacuum, why the hell are you testing at atmospheric pressure anyways? :shrug:

I would guess it would be more expensive and they don't have large funding for some nutjob's ideas?

 

[kamaz]

I would guess it would be more expensive and they don't have large funding for some nutjob's ideas?

The test was actually done in a vaccuum chamber -- it just wasn't hermetized because of some practical issues.

I woudn't publish tests not done in vaccuum, but I can understand the pressure to publish -- they can now use the anomaly to ask for more money (i.e. time on the rig) to do the vaccuum tests. That's how science works today unfortunately.

---------- Post added at 12:24 AM ---------- Previous post was at 12:21 AM ----------

Simple electromagnetic interaction between conductive waveguide and other metal parts in the vicinity. The test chamber has not been exactly large and filled with other metal parts.

Are you suggesting that the device pushed against the chamber walls via the e-m interaction?

 

[RisingFury]

 

[Urwumpe]

Are you suggesting that the device pushed against the chamber walls via the e-m interaction?

Yes. Or they simply didn't match impedance of antenna and transmitter properly and created a force by heating the air. If you are just off by a few per cent from the correct value, you can have a few kilowatts of power heating the antenna instead of being transmitted.

 

[kamaz]

Yes. Or they simply didn't match impedance of antenna and transmitter properly and created a force by heating the air.

In other words, the device produced thrust. Of course it produced thrust through a different mechanism than they hoped, and one which is not very usable practically... but it nonetheless produced thrust.

 

[Urwumpe]

In other words, the device produced thrust. Of course it produced thrust through a different mechanism than they hoped, and one which is not very usable practically... but it nonetheless produced thrust.

They produced a force that they measured. That's all that we are all saying here. Remember: Not every force is thrust.

But you can also produce a force to measure on such a pendulum by walking from one side of the room to the other.

Depending on the kind of tether they used for the balance, they could even cause a twisting force by heating the tether by a fraction of a degree Kelvin.

But my personal favourite pet theory there is, that the strong RF field simply induced rotating AC currents in metal parts, not much different to an asynchronous electric motor. Since the power of such induced currents in the metal depend on the strength of the RF field, a better antenna should produce stronger currents and thus generate a stronger torque on the tether.

After all, that's the big difference of this "engine" compared to the previously tested RF ion thrusters on such test stands: The RF field is not (mostly) confined to the discharge chamber, but fully emitted into the test chamber. Additionally to the ambient air pressure in the test chamber.

 

[kamaz]

After all, that's the big difference of this "engine" compared to the previously tested RF ion thrusters on such test stands: The RF field is not (mostly) confined to the discharge chamber, but fully emitted into the test chamber. Additionally to the ambient air pressure in the test chamber.

Yep. My preferred alternative explanation is that they have produced a ionocraft.

 

[Urwumpe]

Spiegel Online has now picked up the topic... really really bad work IMHO

http://www.spiegel.de/wissenschaft/...ntrieb-liefert-schub-ohne-sprit-a-984520.html

Including the wrong SI conversion from micronewtons into newtons: 30 µN are not 0.0003 N, but actually .00003 N

 

[kamaz]

It's an excellent example of double standard employed by academia. NIF pumps megawatts of laser power to obtain several joules of fusion energy, but I have yet to see this level of ridicule... Although it would be more justified given the colossal waste of taxpayer's money involved. Also, it has never achieved ignition, it will probably never achieve ignition, yet it was sold to the taxpayer as National Ignition Facility -- but I see nobody claiming that the taxpayer was defrauded.

 

[Urwumpe]

NIF pumps megawatts of laser power to obtain several joules of fusion energy, but I have yet to see this level of ridicule...

They also don't claim that they have just invalidated all known laws of physics.

Also 14 kJ out of 1.8 MJ is still a much better performance than 50 µN out of 20 kW.

Also, it has never achieved ignition, it will probably never achieve ignition, yet it was sold to the taxpayer as National Ignition Facility -- but I see nobody claiming that the taxpayer was defrauded.

Still, it does the science for which it was really constructed. Simulating nuclear fusion in hydrogen bombs. :lol: