Author Topic: EM Drive Developments - related to space flight applications - Thread 2  (Read 1643704 times)

Offline Chris Bergin

Thread 1:
http://forum.nasaspaceflight.com/index.php?topic=29276.0

Problems with Thread 1 explained (note the things to avoid in the new thread):
http://forum.nasaspaceflight.com/index.php?topic=29276.msg1301657#msg1301657

Thus Thread 2, with more focus on space flight applications to ensure this can have a healthy home here. Remember, this is a space flight site.


Offline RotoSequence

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I really do hope they EM drive theorists are onto something; if it works, and depending on how well it works, the space flight applications range from replacing maneuvering thrusters to decreasing the cruising times of missions. If, by some miracle of physics, EM drives work spectacularly well, they could replace chemical rocketry for orbital insertion completely and make space access trivial.

If EM drives offer any degree of thrust, telecommunications and science missions will benefit considerably. If it's possible to supply a lot of thrust, they'll literally change the destiny of humanity. But first, we need to know if they work or not. The theories are certainly intriguing, and there are a fair few anecdotal hints that there is something there, but as the several hundred pages of the previous thread show, figuring out what's going on is a real bear.
« Last Edit: 12/12/2014 05:31 PM by RotoSequence »

Offline RonM

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Chris, thanks for cleaning up the old thread. There is a lot of good discussion and information in there.

EM drives would have to push or pull against something. The favorite explanation seems to be the Mach Effect, but is there any experimental evidence that points to the Mach Effect being real? Since the origin of inertia seems to be the key, what about the Higgs field? Local gravitational field?

Although I have my doubts, the potential payoff for spaceflight is so large, this should be looked into, but the experiments need to be rigorously done and repeatable.

Offline MP99

Thanks, Chris.

I really do want to follow this, on the chance that it bears out. There was some good stuff on that thread, but a low s/n ratio combined with a high post count, at the long-ago point I stopped following.

Hoping this will do better. (Might even suggest you leave the old thread open to allow this one to stay cleaner, but know that wouldn't work!)

Cheers, Martin

Offline Star One

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Has there been the least indication yet when we are too get some more results in relation to those who are experimenting in this area?
« Last Edit: 12/12/2014 06:52 PM by Star One »

Offline HMXHMX

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Has there been the least indication yet when we are too get some more results in relation to those who are experimenting in this area?


This paper, presented at the Joint Propulsion Conference this past summer in Cleveland, should address your question.


Online cuddihy

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Wow, great paper, Gary! Thanks for pointing it out. I see SSI's efforts got a mention as well.

Interesting this seems to be picking up steam just as Hollywood put out a Sci-Fi movie that takes Space-time, wormholes, and gravity seriously.
« Last Edit: 12/13/2014 04:52 AM by cuddihy »

Offline RotoSequence

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Well, looking at the thermistor data with the PZT stack mach effect thruster, whatever it's doing doesn't look like a transient thermal effect...

« Last Edit: 12/13/2014 05:50 AM by RotoSequence »

Offline SteveKelsey

That is a very interesting paper. Very clean results compared to previous presentations and the Hoyl and Narliker approach to theory looks promising. It needs to be emphasised that this is an ME device, not EM, and that the paper reports that the theory is a work in progress.
« Last Edit: 12/13/2014 09:08 AM by SteveKelsey »
2001 is running a little late, but we are getting there.

Offline Notsosureofit

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Only had a quick look at the paper.  I would like to know the positioning of the accelerometer.  If this is a displacement or zero set type balance the acceleration during the constant thrust segment should be zero.  Possibly the mounting accounts for this ??

Edit:  OK.  The "accelerometer" is between the PZT.  It is not the system accelerating, just an indication that the transducers are receiving power.
« Last Edit: 12/13/2014 01:16 PM by Notsosureofit »

Offline HMXHMX

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Well, looking at the thermistor data with the PZT stack mach effect thruster, whatever it's doing doesn't look like a transient thermal effect...



I can attest that it is not thermal.  It works in a vacuum.  It works in a Faraday cage and it works when you reverse the device (the thrust reverses).

Offline HMXHMX

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That is a very interesting paper. Very clean results compared to previous presentations and the Hoyl and Narliker approach to theory looks promising. It needs to be emphasised that this is an ME device, not EM, and that the paper reports that the theory is a work in progress.

Quite so.  Perhaps the thread needs to be called "Space Drive" (a la Arthur C. Clarke), or "Propellantless Propulsion."

Online Rodal

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"With more focus on space flight applications " (as per http://forum.nasaspaceflight.com/index.php?topic=36313.msg1301658#msg1301658) the metric chosen by the NASA's "Anomalous" report was the thrust force per power input.

EDIT: Dimensions for Shawyer's and Brady et.al.'s cavities updated as per latest estimates on 05/20/15

Here is a comparison of reported measurements for EM Drives and for the latest report by Fearn, Zachar, Woodward & Wanser.

Notice that the force per power input reported by  Fearn, Zachar, Woodward & Wanser is several orders of magnitude lower than the "EM drives".  Actually it is barely (3.5 times higher) more than the force per power input of a photon rocket:

reported measurement ForcePerPowerInput (milliNewtons/kW)

(* Cannae Superconducting *)             761.9 to 952.4
(* Shawyer Demo *)                               80 to 243
(* Shawyer Experimental *)                   18.82
(* Brady c TE mode *)                             21.31
(* Brady a TM mode*)                               5.396
(* Brady b TM mode*)                               3.000
(*Fearn, Zachar, Woodward & Wanser*) 0.01176




lengths in meter
rfFrequency in 1/second (microwave frequency during test)
power in watts
force in milliNewtons
force per PowerInput in milliNewtons/kW
c= 299705000 m/s (speed of light in air)
c= 299792458 m/s (speed of light in vacuum) (for Cannae Superconducting)
(the difference between c in air compared to c in vacuum is negligible)


Note: SmallDiameter for Shawyer's EM Drives obtained from his reported ShawyerDesignFactor .


Force/PowerInput of a Photon Rocket = 1 / c


(* Cannae Superconducting *)
rfFrequency = 1.047*10^9;
cavityLength = 0.01+0.004+0.006+0.01 = 0.03;
bigDiameter =(22.86-2*(0.00430)) = 0.220;
smallDiameter = bigDiameter-2*0.01=0.200;

power =  10.5
Q = 1.1*(10^7)

measured force = 8 to 10
measured ForcePerPowerInput = 761.9 to 952.4
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket = 228,400 to 285,500


(* Shawyer Experimental *)
rfFrequency=2.45*10^9;
cavityLength=0.156;(estimated from photographs)
bigDiameter=0.16; (given by Shawyer)
smallDiameter=0.1025; (obtained from the Design Factor, bigDiameter and frequency provided by Shawyer)
Design Factor = 0.497;
power =  850;   
Q = 5900 ;

measured force = 16
measured ForcePerPowerInput = 18.82
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =5,640


(* Shawyer Demo *)
rfFrequency=2.45*10^9;
cavityLength=0.345;(estimated from photographs)
bigDiameter=0.28;(given by Shawyer)
smallDiameter=  0.09613; (from the Design Factor, bigDiameter and frequency provided by Shawyer)
Design Factor = 0.844;
power =  421 to 1200;
Q = 45000;

(measured force = 102.30 milliNewtons only reported for  421 watts, 243 milliNewtons/kW )

measured ForcePerPowerInput = 80 to 243
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =23,980 to 72,830

All Brady cases have the following dimensions:

cavityLength=0.2286; (provided by Paul March)
bigDiameter=0.2794; (provided by Paul March)
smallDiameter=0.15875; (provided by Paul March)


(* Brady a TM mode*)
rfFrequency=1.9326*10^9;

power =   16.9 
Q = 7320

measured force =  0.0912
measured ForcePerPowerInput = 5.396
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =1,617.2


(* Brady b TM mode*)   
rfFrequency=1.9367*10^9;

power = 16.7
Q =  18100

measured force = 0.0501
measured ForcePerPowerInput = 3.000
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =899.12


  (* Brady c  TE mode *)
rfFrequency = 1.8804*10^9;

power = 2.6
Q = 22000

measured force = 0.05541
measured ForcePerPowerInput = 21.31
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =6,386.7


(* Fearn, Zachar, Woodward & Wanser*)
rfFrequency = 39,300;

power =  170

measured force = 0.002
measured ForcePerPowerInput = 0.01176
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket = 3.526

 
« Last Edit: 05/20/2015 04:33 PM by Rodal »

Offline birchoff

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"With more focus on space flight applications " (as per http://forum.nasaspaceflight.com/index.php?topic=36313.msg1301658#msg1301658) the metric chosen by the NASA's "Anomalous" report was the thrust force per power input.


Here is a comparison of reported measurements for EM Drives and for the latest report by Fearn, Zachar, Woodward & Wanser.

Notice that the force per power input reported by  Fearn, Zachar, Woodward & Wanser is several orders of magnitude lower than the "EM drives".  Actually it is barely (3.5 times higher) more than the force per power input of a photon rocket:

reported measurement ForcePerPowerInput (milliNewtons/kW)

(* Cannae Superconducting *)             761.9 to 952.4
(* Shawyer Demo *)                               80 to 243
(* Shawyer Experimental *)                   18.82
(* Brady c TE mode *)                             21.31
(* Brady a TM mode*)                               5.396
(* Brady b TM mode*)                               3.000
(*Fearn, Zachar, Woodward & Wanser*) 0.01176




lengths in meter
rfFrequency in 1/second (microwave frequency during test)
power in watts
force in milliNewtons
force per PowerInput in milliNewtons/kW
c= 299705000 m/s (speed of light in air)
c= 299792458 m/s (speed of light in vacuum) (for Cannae Superconducting)
(the difference between c in air compared to c in vacuum is negligible)


Note: SmallDiameter for Shawyer's EM Drives obtained from his reported ShawyerDesignFactor .


Force/PowerInput of a Photon Rocket = 1 / c


(* Cannae Superconducting *)
rfFrequency = 1.047*10^9;
cavityLength = 0.01+0.004+0.006+0.01 = 0.03;
bigDiameter =(22.86-2*(0.00430)) = 0.220;
smallDiameter = bigDiameter-2*0.01=0.200;

power =  10.5
Q = 1.1*(10^7)

measured force = 8 to 10
measured ForcePerPowerInput = 761.9 to 952.4
Force/PowerInput of a Photon Rocket =0.003336
measured ForcePerPowerInput to the one of a photon rocket = 228,400 to 285,500


(* Shawyer Experimental *)
rfFrequency=2.45*10^9;
cavityLength=0.156;
bigDiameter=0.16;
smallDiameter=0.127546;

power =  850   
Q = 5900

measured force = 16
measured ForcePerPowerInput = 18.82
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =5,640


(* Shawyer Demo *)
rfFrequency=2.45*10^9;
cavityLength=0.345;
bigDiameter=0.28;
smallDiameter= 0.128853

power =  421 to 1200
Q = 45000

(measured force = 102.30 milliNewtons only reported for  421 watts, 243 milliNewtons/kW )

measured ForcePerPowerInput = 80 to 243
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =23,980 to 72,830

All Brady cases have the following dimensions:

cavityLength=0.332;
bigDiameter=0.397;
smallDiameter=0.244;


(* Brady a TM mode*)
rfFrequency=1.9326*10^9;

power =   16.9 
Q = 7320

measured force =  0.0912
measured ForcePerPowerInput = 5.396
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =1,617.2


(* Brady b TM mode*)   
rfFrequency=1.9367*10^9;

power = 16.7
Q =  18100

measured force = 0.0501
measured ForcePerPowerInput = 3.000
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =899.12


  (* Brady c  TE mode *)
rfFrequency = 1.8804*10^9;

power = 2.6
Q = 22000

measured force = 0.05541
measured ForcePerPowerInput = 21.31
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket =6,386.7


(* Fearn, Zachar, Woodward & Wanser*)
rfFrequency = 39,300;

power =  170

measured force = 0.002
measured ForcePerPowerInput = 0.01176
Force/PowerInput of a Photon Rocket =0.003337
measured ForcePerPowerInput to the one of a photon rocket = 3.526

While the force per power input is smaller, at least the ME work seems to be much furhter along. After skimming the newest paper I also noticed that there is an additional paper that was published this year focusing on the experimental results.

http://www.researchgate.net/profile/Heidi_Fearn/publication/264040874_EXP-tests13/links/00b4953c9a2675bcc0000000?ev=pub_ext_doc_dl&origin=publication_list&inViewer=true

Only half way through reading this paper but it seems like more more effort was given to potential spurious forces, compared to the published information we have available for the EM Drives.

Offline Star One

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I'm glad to see the discussion continued in this thread.  I must admit, I felt disappointed at the prospect of losing this resource and the small band of interested theorists and experimentalists exploring what may appear to be the impossible, but which may ultimately result in profound space flight applications.

Might I suggest, that if this forum turns out not to be the right place in the future (e.g., if the thread is removed again), that all those who maintain an interest in the topic to congregate in the http://www.reddit.com/r/emdrive forum.  In fact, I suggest that you bookmark that page now for future reference.

I too do not appreciate personal attacks, which have no place in this kind of discussion, and so I understand the desire to keep the thread clean.  On the other hand, this topic is too important not to keep alive.
Can I just thank you for providing that link as it appears to be a good source of information on this topic.

Offline HMXHMX

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"With more focus on space flight applications " (as per http://forum.nasaspaceflight.com/index.php?topic=36313.msg1301658#msg1301658) the metric chosen by the NASA's "Anomalous" report was the thrust force per power input.


Here is a comparison of reported measurements for EM Drives and for the latest report by Fearn, Zachar, Woodward & Wanser.

Notice that the force per power input reported by  Fearn, Zachar, Woodward & Wanser is several orders of magnitude lower than the "EM drives".  Actually it is barely (3.5 times higher) more than the force per power input of a photon rocket:

reported measurement ForcePerPowerInput (milliNewtons/kW)

(* Cannae Superconducting *)             761.9 to 952.4
(* Shawyer Demo *)                               80 to 243
(* Shawyer Experimental *)                   18.82
(* Brady c TE mode *)                             21.31
(* Brady a TM mode*)                               5.396
(* Brady b TM mode*)                               3.000
(*Fearn, Zachar, Woodward & Wanser*) 0.01176



...

Quite true.  "And yet, it moves."  :)

Online Rodal

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....
While I was sceptic and still am, I learned a lot of interesting things from the previous thread, and enjoyed it even with its defaults.
It's great to have you posting again here, Frobnicat, as your always thoughtfully scientific and frobnicating posts have been one of the main attractions of this thread.

Welcome back, frobnicat !

I hope that Mulletron & all the others return to post here again as well,  and sooner rather than later !
« Last Edit: 12/16/2014 02:41 PM by Rodal »

Offline D_Dom

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Excellent stuff indeed, I will be perusing the previous thread in an attempt to better understand the logic. Easy enough for me to ignore the nonsense. Hoping we see more evidence from the many experiments underway to fuel the discussion. Many thanks to all the contributing members, truly a thought provoking thread.
Space is not merely a matter of life or death, it is considerably more important than that!

Offline Raj2014

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What is the latest news on the EM Drive? What are they planning to do next? If the EM Drive does work, this will be amazing, space exploration will change.

Offline frobnicat

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May I suggest that people interested in "Mach effect" (reality of which having obvious consequences on directions advanced spaceflight can take) contribute on a thread with a more appropriate explicit topic (and historical content) : Propellantless Field Propulsion and application. The risk in splitting the somewhat frozen propellantless discussion of late would be to make it even harder to revive some activity, but EM and ME approaches are two very different kind of theories and devices, interwining of both topic discussion in a single thread was one of the reason of the chaos that plagued the 1st EM drive thread.

Anyhow, for those interested in Mach effect, here are two versions of results from attempt of Woodward (2008...) at "proof of effect" exhumed from Propellantless thread:
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=13020.0;attach=260412
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=13020.0;attach=260481

Haven't read in detail yet.
I won't crosspost here my posts about that (if I have the courage to address some of it deeper)
http://forum.nasaspaceflight.com/index.php?topic=13020.msg1304798#msg1304798

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