Author Topic: EM Drive Developments Thread 1  (Read 1472783 times)

Offline brokndodge

  • Member
  • Posts: 20
  • Liked: 2
  • Likes Given: 30
Re: EM Drive Developments
« Reply #180 on: 08/04/2014 09:10 pm »
I think they did the test with an RF load also.
They reported no force in this case. That must go someway to eliminating systemic errors in their setup.

No, they reported there was some thrust detected from the RF load, also, but not as much, and they subtracted that from the measured thrust for the other two devices.
They did? Going back over the abstract they mention the RF load, but nothing about testing of such.
Did I just overlook it or do you have extra info?

There are two sets of tests mentioned in the actual paper (not the NASA abstract).  The first set of tests were limited in power due to RF leakage from the vacuum chamber.  That set of tests was limited to 935 KHz to prevent such leakage.  Three apparatus were tested.  The first 2 were nearly identical pancake shaped devices.  The first of those those had groves cut into the inside rear face of the pancake.  The engineer believed that those grooves would cause or increase the thrust created by it.  The second did not have grooves and is the one refereed to as the null device.  The engineer believed that the absence of grooves in this version would prevent it from creating thrust.  Now, the third apparatus was a simple RF modulator and was the control.  In this first set of tests conducted in August of 13, the first 2 devices created a thrust effect that was nearly identical disproving the engineers theory.  The third (control) apparatus produced 0 thrust at the same power levels used on the first 2.

There was a second set of tests performed on a different device in early 2014.  This test used lessons learned from the first set to eliminate the RF leakage above 1MHz in the vacuum chamber.  During this test there were two apparatus.  The test apparatus and the control which was similar to the control used in the first test.  The control did create about 9.2microN of thrust.  This was determined to be caused by electromagnetic interaction with some magnets inside the vacuum chamber and was compensated for.  I don't know if it was compensated for mathematically or thru physical shielding.  They ran the test apparatus thru a range of frequencies and did achieve varying degrees of thrust that were significant compared to their control.

Offline brokndodge

  • Member
  • Posts: 20
  • Liked: 2
  • Likes Given: 30
Re: EM Drive Developments
« Reply #181 on: 08/04/2014 09:17 pm »
IANAS - But, I have read the report and it seems to me that they are only reporting on experimental results that they could not explain and honestly didn't expect to see.  The first set of experiments and the "null" (they should have chosen a better word) device indicated results that were unexpected and invalidated 1 theory as to why results were seen.  The so called "null" device was not really such a device. Rather, the engineer that made it had a theory that placing groves in one end of the device would create thrust and that not having the grooves would not create thrust.  He was proven wrong in that the device appeared to create thrust irregardless of the groves. 

The second set of experiments conducted with a different device of a type more closely related to the EMDrive also yielded results.  They were able to take lessons learned about their first experimental setup and apply them to the second set of tests.  As such they were able to test at much higher frequencies. 

Among all of the tests, time available to test has been an issue. They stated in the opening brief about the setup of their vacuum chamber and pendulum that it takes "days" to pull an appropriate vacuum.  Later in the paper they stated that one of the devices used had electrical components that were not vacuum friendly.  I don't recall a specific mention of the second set of tests being performed in a vacuum. 

The paper did not make any conclusions as to what is causing the effect that they are seeing.  It does state that the effect is worth investigating and that they are planning to test a more powerful 1GHz version at other facilities with better equipment.  I believe that at this time such an advanced concept lab as this is doing the right thing in further researching the results that they measured.  I also believe that they are confident to a high enough degree to warrant larger scale testing at facilities that are better equipped for such tests. 

I look forward to the results of such testing whether they be positive or negative.
Great post.
I may be slow today, but could you supply a link to the paper please?
Cheers mate.

See below from about page 6 of this very thread.  When you follow the link you will have to skip past about 2 or 3 paragraphs of the guy discounting the results to find two links to the actual paper:

The problem is that the article linked is not a scientific paper, but a clearly preliminary technical report, the typical "hat on the seat" (copyrighted by me :) ) paper required to ensure to be the first IF a sensational result is confirmed in order to get an high citation index in the future.
A link to the actual paper may be found at
https://plus.google.com/117663015413546257905/posts/C7vx2G85kr4

However this is a conference paper, which in many cases aren't peer reviewed in the same way a journal paper would be. I'm not sure about this particular case.

In any case, if Baez summery is correct, there is really nothing worth talking about here... (which should be no surprise to anyone who read the original abstract)

Offline IslandPlaya

  • Full Member
  • ****
  • Posts: 582
  • Outer Hebrides
  • Liked: 164
  • Likes Given: 166
Re: EM Drive Developments
« Reply #182 on: 08/04/2014 09:26 pm »
Awesome. Some good night-time reading!
Thanks.

Offline hop

  • Senior Member
  • *****
  • Posts: 3352
  • Liked: 553
  • Likes Given: 891
Re: EM Drive Developments
« Reply #183 on: 08/04/2014 09:41 pm »
See below from about page 6 of this very thread.  When you follow the link you will have to skip past about 2 or 3 paragraphs of the guy discounting the results to find two links to the actual paper:
On the other hand, anyone interested in the plausibility (or otherwise) of this result may find reading the post and discussion in the comments to be time well spent.

Offline IslandPlaya

  • Full Member
  • ****
  • Posts: 582
  • Outer Hebrides
  • Liked: 164
  • Likes Given: 166
Re: EM Drive Developments
« Reply #184 on: 08/04/2014 09:47 pm »
On the gripping hand we are discussing it here.
Any insights you may have had from reading that post, please repeat here.
I have speed read the paper. Seems very thorough. Of course speed-reading is not good. But at the moment I think they have found something.

Offline ChrisWilson68

  • Senior Member
  • *****
  • Posts: 5266
  • Sunnyvale, CA
  • Liked: 4992
  • Likes Given: 6459
Re: EM Drive Developments
« Reply #185 on: 08/04/2014 10:11 pm »
I think they did the test with an RF load also.
They reported no force in this case. That must go someway to eliminating systemic errors in their setup.

No, they reported there was some thrust detected from the RF load, also, but not as much, and they subtracted that from the measured thrust for the other two devices.
They did? Going back over the abstract they mention the RF load, but nothing about testing of such.
Did I just overlook it or do you have extra info?

From reply #88 in this thread:

Quote
We're talking of net thrust because of course the setup was also tested with a null 50 ohm load connected, in order to cancel the effect from the drives and detect any detect any spurious force due to EM coupling with the whole apparatus (which exists, at 9.6 µN) and this "null" spurious force was evidently subtracted from any thrust signal due to the drives then tested on the pendulum.

Offline IslandPlaya

  • Full Member
  • ****
  • Posts: 582
  • Outer Hebrides
  • Liked: 164
  • Likes Given: 166
Re: EM Drive Developments
« Reply #186 on: 08/04/2014 10:17 pm »
Yes. I have the paper now to check for myself.
Thanks anyway

Offline Star One

  • Senior Member
  • *****
  • Posts: 13997
  • UK
  • Liked: 3974
  • Likes Given: 220
Re: EM Drive Developments
« Reply #187 on: 08/04/2014 10:26 pm »
To say there is a lot of scepticism on that link is an understatement.

Offline IslandPlaya

  • Full Member
  • ****
  • Posts: 582
  • Outer Hebrides
  • Liked: 164
  • Likes Given: 166
Re: EM Drive Developments
« Reply #188 on: 08/04/2014 10:43 pm »
I think in these things we have to be very careful.
There are two camps:-
1) People who would very much like it to be true.
2) People who say it is (obviously) impossible.

I would put myself in (1) but that doesn't mean I wouldn't except hard results disproving the effect.
Anyway, whichever camp you are in, it pays to be objective and not succumb to confirmation bias.
It can be difficult to do this, but we must try...
« Last Edit: 08/04/2014 10:44 pm by IslandPlaya »

Offline Star One

  • Senior Member
  • *****
  • Posts: 13997
  • UK
  • Liked: 3974
  • Likes Given: 220
Re: EM Drive Developments
« Reply #189 on: 08/04/2014 10:48 pm »

I think in these things we have to be very careful.
There are two camps:-
1) People who would very much like it to be true.
2) People who say it is (obviously) impossible.

I would put myself in (1) but that doesn't mean I wouldn't except hard results disproving the effect.
Anyway, whichever camp you are in, it pays to be objective and not succumb to confirmation bias.
It can be difficult to do this, but we must try...

Excellent post. I would say I am now of the same view as you on this topic.

Offline FlyingMoose

  • Member
  • Posts: 3
  • New York
  • Liked: 3
  • Likes Given: 0
Re: EM Drive Developments
« Reply #190 on: 08/05/2014 07:21 pm »

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.

This would really make an interesting subject to read or a comparison point to read up on.
who you be able to supply a link or a paper?

I have spent about 5 hours and have been unable to find it again.  Google is worthless because any keywords I can think of only find hundreds of news articles about the recent NASA experiment.  It was a mention in a forum, it wasn't an official paper.  Perhaps someone with better google-fu can find it.

Offline sghill

  • Full Member
  • ****
  • Posts: 1682
  • United States
  • Liked: 2092
  • Likes Given: 3200
Re: EM Drive Developments
« Reply #191 on: 08/05/2014 07:34 pm »
You might want to be rather careful in what you say here otherwise it might look like you're casting aspersions on the NASA scientists and their decision to investigate this.

This is one little corner of NASA.  NASA is a huge organization with lots and lots of people working on lots of things.  Sonny White and friends are not equivalent to NASA as a whole.

And there's nothing wrong with complaining that this one small part of NASA is wasting precious resources that could be better spent, and misleading the public by letting the NASA name get attached to wishful thinking in the guise of science.

Consider this.  Eagleworks is trying to get their inferometer apparatus up and running, and learn how to use it properly for their own proposed warp bubble and Q-thruster experiments.  This experiment- who cares if it's quackery or not- gave them a perfect chance to try out their methods on a completely 3rd party apparatus.  That, in turn, allows them to refine their methods for their own experiments.

If the EMDrive theories are valid, then so much the better.  It still worked to Eagleworks- and NASA's advantage to go through the testing motions without drinking the EMDrive Kool Aid.  The fact that the released paper focused on the testing procedures reinforces this theory IMHO.  Also, I think the soundness of Eagleworks performing this testing is further reinforced by the fact that the test article also generated thrust, so there were possibly problems (again IMHO) in their procedures that this testing exposed.

In other words, it's better for them to report false positives with the EMDrive thruster than their own Q-thruster right?!? :)
« Last Edit: 08/05/2014 07:38 pm by sghill »
Bring the thunder!

Offline Star One

  • Senior Member
  • *****
  • Posts: 13997
  • UK
  • Liked: 3974
  • Likes Given: 220
Re: EM Drive Developments
« Reply #192 on: 08/05/2014 08:48 pm »
A rather bizarre argument has blown up on this over at the Polywell forums on the main thread, I am not going to clog this forum with it but it did leave me rather scratching my head. I don't think I've known any other recent scientific story that's attracted such odd commentary, it's made me despair of whole chunks of the internet.:) This forum is a positive oasis of sanity.
« Last Edit: 08/05/2014 09:03 pm by Star One »

Offline aero

  • Senior Member
  • *****
  • Posts: 3629
  • 92129
  • Liked: 1145
  • Likes Given: 360
Re: EM Drive Developments
« Reply #193 on: 08/05/2014 08:51 pm »
In case it hasn't been posted, the full AIAA paper is available here:

http://www.scribd.com/doc/235868930/Anomalous-Thrust-Production-from-an-RF-Test-Device-Measured-on-a-Low-Thrust-Torsion-Pendulum

A quick scan discovered the interesting item, that not two, but four devices were tested and reported. Three resulted in force being measured repeatably. Two devices were the disk shaped Cannae device, one of which was designed for null results but produced force anyway, one device was the Eagelworks in-house design, a conical shaped device similar the original Roger Shawyer and the chinese devices and the fourth device was a brick shaped RF load. It did not produce thrust.

So what we have is at least 5 devices which have been reported as producing thrust, and at least 3 different test set-ups that have been blamed as being faulty by the blogger community, each with a different fault. To me, it seems time to apply Occam's razor.

It is easy to show that the undetected flaw which the EagleWorks Lab is accused of, would not have gone undetected at the Chinese high power test. The suspected flaw is force resulting from heating and convective air flow. But in the Chinese high power test in order for this mechanism to give the measured force, the mass of air flow (mdot)  times the change in air velocity (Ve) must equal the measured force. But that air flow would be easily detected by anyone who casually glanced at the operating device. So the flaw is different for different test set-ups.

So in the end, there can be either a different flaw for each test set-up, or there can be one unknown but reproducible force generating mechanism. What does Occam's razor say?
Retired, working interesting problems

Offline aero

  • Senior Member
  • *****
  • Posts: 3629
  • 92129
  • Liked: 1145
  • Likes Given: 360
Re: EM Drive Developments
« Reply #194 on: 08/05/2014 08:57 pm »
If you want to see bizarre, go here:

http://www.physforum.com/index.php

But this is a hot blogger topic world wide, I checked a French and Czech blog site (Google Translate) and they seem to be very hard over on this subject, too. Most bloggers seem to behave as though they fear that the EM drive will steal their women and destroy their sex life.
Retired, working interesting problems

Offline Star One

  • Senior Member
  • *****
  • Posts: 13997
  • UK
  • Liked: 3974
  • Likes Given: 220
Re: EM Drive Developments
« Reply #195 on: 08/05/2014 09:12 pm »

If you want to see bizarre, go here:

http://www.physforum.com/index.php

But this is a hot blogger topic world wide, I checked a French and Czech blog site (Google Translate) and they seem to be very hard over on this subject, too. Most bloggers seem to behave as though they fear that the EM drive will steal their women and destroy their sex life.

See my post above I have genuinely been concerned by some of the commentary related to this I've read.

Offline GregA

  • Full Member
  • ****
  • Posts: 524
  • Liked: 269
  • Likes Given: 61
Re: EM Drive Developments
« Reply #196 on: 08/05/2014 10:33 pm »
Guys I applaud trying to stay on topic, but you're giving so little detail I have no idea what you're talking about. Going to that site shows some terrible "scientific" thoughts, is that what you mean.

Perhaps it needs a separate thread on "misunderstanding science" or whatever the concern is - otherwise an illustration of your concern would be great :)

Offline aero

  • Senior Member
  • *****
  • Posts: 3629
  • 92129
  • Liked: 1145
  • Likes Given: 360
Re: EM Drive Developments
« Reply #197 on: 08/05/2014 11:29 pm »
Guys I applaud trying to stay on topic, but you're giving so little detail I have no idea what you're talking about. Going to that site shows some terrible "scientific" thoughts, is that what you mean.

Perhaps it needs a separate thread on "misunderstanding science" or whatever the concern is - otherwise an illustration of your concern would be great :)

A problem with blogging about EM Drive is this: There are no theoretical underpinnings to the experimental devices. That means that there is no means to evaluate the experiment performed relative to the underlying theory since there isn't any. Well, that's not quite true, there are home grown ideas of a theory for each experimenter, but no theory that is accepted outside its own laboratory. Some of the theories seem laughable and some of them have been proven to be wrong.

The situation as it stands currently is that the general blogger community spends their creative energy trying to imagine a flaw in the experiments which would give the measured results. Of course flaws can be imagined and theories can be laughed at, but doing so does not advance scientific knowledge, and worse, such possible flaws are advanced very loudly without benefit of understanding the published papers which in some cases clearly describe actions taken by the experimenter to avoid such flaws.

It seems that the widely held belief is "If it is not explained by the Standard Model, then it is not physics."

What I had hoped is that some knowledgeable people would propose an idea for a theory that could then be massaged by the community into something worthy of consideration. Instead what I have found is that when a germ of an idea is presented the response is, along the lines of, "There was no force, it was a deflection of a spring which could have been caused by ...(this or that reason). Engineers can't do science, only scientists can do science." In the end, the experimenters are commonly accused of holding their thumbs on the scales.

But that is just my observation. There are several papers about EM Drive available on the internet, including the NASA paper I linked above. Read the full paper, not just the abstract, then check some of the blog sites around the net. I think you will see the lack of rational thought for yourself.
Retired, working interesting problems

Offline ChrisWilson68

  • Senior Member
  • *****
  • Posts: 5266
  • Sunnyvale, CA
  • Liked: 4992
  • Likes Given: 6459
Re: EM Drive Developments
« Reply #198 on: 08/06/2014 02:58 am »
In case it hasn't been posted, the full AIAA paper is available here:

http://www.scribd.com/doc/235868930/Anomalous-Thrust-Production-from-an-RF-Test-Device-Measured-on-a-Low-Thrust-Torsion-Pendulum

A quick scan discovered the interesting item, that not two, but four devices were tested and reported. Three resulted in force being measured repeatably. Two devices were the disk shaped Cannae device, one of which was designed for null results but produced force anyway, one device was the Eagelworks in-house design, a conical shaped device similar the original Roger Shawyer and the chinese devices and the fourth device was a brick shaped RF load. It did not produce thrust.

So what we have is at least 5 devices which have been reported as producing thrust, and at least 3 different test set-ups that have been blamed as being faulty by the blogger community, each with a different fault. To me, it seems time to apply Occam's razor.

It is easy to show that the undetected flaw which the EagleWorks Lab is accused of, would not have gone undetected at the Chinese high power test. The suspected flaw is force resulting from heating and convective air flow. But in the Chinese high power test in order for this mechanism to give the measured force, the mass of air flow (mdot)  times the change in air velocity (Ve) must equal the measured force. But that air flow would be easily detected by anyone who casually glanced at the operating device. So the flaw is different for different test set-ups.

So in the end, there can be either a different flaw for each test set-up, or there can be one unknown but reproducible force generating mechanism. What does Occam's razor say?

The proper question to ask of Occam's razor whether it's more likely that three small groups made mistakes in their test setups that gave them the results they desperately wished to see, or that tens of thousands of physicists working over decades completely failed to find an effect that is easy to produce on a variety of different devices that are simple to make.

Offline ChrisWilson68

  • Senior Member
  • *****
  • Posts: 5266
  • Sunnyvale, CA
  • Liked: 4992
  • Likes Given: 6459
Re: EM Drive Developments
« Reply #199 on: 08/06/2014 03:02 am »
Of course flaws can be imagined and theories can be laughed at, but doing so does not advance scientific knowledge

If there is a good reason to suspect an experimental flaw, pointing out that reason and spreading the idea about that flaw does absolutely advance scientific knowledge.

Tags:
 

Advertisement NovaTech
Advertisement Northrop Grumman
Advertisement
Advertisement Margaritaville Beach Resort South Padre Island
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
1