Author Topic: EM Drive Developments - related to space flight applications - Thread 10  (Read 1635443 times)

Offline aero

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Yes, Dr. Rodal, I understand that. The PFRC engine concept is targeted to a 4-year mission to Pluto with time on station. The reason I posted is to point out the spacecraft electrical power available or to become available which could be utilized by an EM drive type engine. The EM drive advantage of no propellant and no massive exhaust nozzle should swing the engineering mass budget advantage to the EM drive but the total thrust is also an important factor.

At the indicated thrust/power from the latest Eagleworks paper of 1.2 mN/kW, the PFRC engine thrust of 5 mN/kW is only a factor of four greater.  Point is that the current best data indicates that the EM drive engines are competitive with the current best data of nuclear-powered reaction engines given similar mission profiles. And I might add that the EW data is measured data while the PFRC data is so far still on paper.

The EM drive is not just a wimpy little thruster as some might think, but rather, it is in the game performance wise, lacking only a belivable concept for thrust generation, a concept that all here are striving dillengently to devise.
« Last Edit: 09/19/2017 05:16 pm by aero »
Retired, working interesting problems

Offline OnlyMe

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Not quite on the current topic, but I found this interesting link over on talkpolywell. There probably is or should be a similar link in advanced concepts.

http://www.talk-polywell.org/bb/viewtopic.php?f=10&t=5341&p=129833#p129833

It relates because the PFRC engine is to provide one MW of power or 5 N of thrust, long-term in a space vehicle.

How does the EM drive stack up to those numbers, which I translate to 5 micro-newtons per Watt?
I don't understand why compare this to the EM Drive based on thrust per input energy.

The direct fusion drive http://www.psatellite.com/fusion/  is a conventional rocket expelling propellant, it just uses fusion instead.



Any comparison of thrust between a rocket expelling propellants and a propellantless concept like the EM Drive is not a fair comparison, because it misses the fact that propellant is a large ratio of the total mass of the vehicle and thus the payload (which is what matters) , duration of flight are not entering in the comparison as they should.

The comparison depends on how far you are attempting to go:

Quote
Reaching Alpha Centauri in anything close to a human lifetime remains a significant challenge, but PFRC could be part of an architecture to reach the star in 300 to 500 years, and slow down enough to go into orbit around the potentially Earth-like planets there!

http://www.psatellite.com/tag/dfd/

Instead of comparing the two, think about the potential of marrying the two in a dual drive vehicle or just using the PFRC reactor as a power plant for stacked EmDrives. I have not read the whole paper but from the first couple of pages, "When scaled up to achieve fusion parameters, PFRC would result in a 4-8 m long, 1.5 m diameter reactor producing 1 to 10 MW.". Think about how many stacked EmDrives you could power with 1 to 10 MW. How much thrust would they need to deliver individually, to be functionally useful?

Payload is really only a significant issue when launching from the earth's surface.., IOW initially overcoming the gravity well. Even from LEO not so much.

A short story as comparison. For a short time when I was yong I worked, as a swictman for a railroad. On one occasion during my introduction to the work, a new boxcar w/then state of the art new roller bearings was set at rest on a flat section of rail. As I remember from checking myself, the light weight was 15-20 tons and load capacity 60 tons. The boxcar was sealed so loaded and thus some where between 20 to 60+ tons. Say just 25 tons (loaded with feathers). Setting on flat rail it took only a few ounces, less than a pound of pressure to roll the car on the track, not working against gravity and with only the relatively small friction from the bearings... From LEO gravity has already largely been over come and friction?

Back to the issue at hand, the PFRC reactor maybe as significant as a power plant for other propulsion systems, as for its potential use as a fusion powered rocket...

Offline Rodal

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...Payload is really only a significant issue when launching from the earth's surface.., IOW initially overcoming the gravity well. Even from LEO not so much....
Not so if one considers getting "there" in a reasonable amount of time, as you still have to overcome inertia in order to reach a given speed.  Look at the tyranny of the rocket equation.

https://www.nasa.gov/mission_pages/station/expeditions/expedition30/tryanny.html

Destination   Energy Cost (km/s)
Surface of Earth to Earth orbit:   8
Earth orbit to cis-lunar locations:
Lagrange points:  3.5
Low Lunar orbit: 4.1

Earth orbit to near-Earth asteroids:   > 4
Earth orbit to surface Moon:   6
Earth orbit to surface Mars:   8  [same as from surface to Earth orbit]

If you want to go Jupiter, Pluto or even more, interstellar, and time is an issue, payload is a huge issue


« Last Edit: 09/19/2017 06:26 pm by Rodal »

Offline OnlyMe

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...Payload is really only a significant issue when launching from the earth's surface.., IOW initially overcoming the gravity well. Even from LEO not so much....
Not so if one considers getting "there" in a reasonable amount of time, as you still have to overcome inertia in order to reach a given speed.  Look at the tyranny of the rocket equation.

https://www.nasa.gov/mission_pages/station/expeditions/expedition30/tryanny.html

Destination   Energy Cost (km/s)
Surface of Earth to Earth orbit:   8
Earth orbit to cis-lunar locations:
Lagrange points:  3.5
Low Lunar orbit: 4.1

Earth orbit to near-Earth asteroids:   > 4
Earth orbit to surface Moon:   6
Earth orbit to surface Mars:   8  [same as from surface to Earth orbit]

If you want to go Jupiter, Pluto or even more, interstellar, and time is an issue, payload is a huge issue

Dr. Rodal,

That's all based on what NASA considers current technology, which means launch pad to desitanition and chemical rockets.

If any of the propellentless drives currently being explored or even just the fusion reactor/drive itself wind up being developed to a useable state, the whole game plan would or should change. And a long game approach a far better and more economical (in the long run) game.

 Once the initial cost of getting to LEO is overcome, any of these would make travel between LEO and the moon almost routine. And the possibility of a permanent base on the moon realistic. From the surface of the moon to a lunar orbit could be accomplished by use of a rail launch system, powered most likely from solar power but alternately by those same fusion power plants. And a Lunar base would place within reach resources in a far easier gravity well to deal with.

At that point Mars would not be that far off. Maybe even a stepping stone to the asteroid belt and once again resources. While maned missions to Jupiter's moons, looks at present like something on the same level as exploring Antarctica, for the science rather than setting up house keeping, even that might wind up in reach.

Even assuming functional EmDrives, manned expeditions to Pluto and the other outer planets, not to mention interstellar adventures, are at present still the stuff of dreams and science fiction.

The real point is that once we have some drive that could operate over an extended period of time, like this fusion powered rocket or an EmDrive system, the moon is no longer really out of reach. Certainly at an upfront cost. But once the moon then far more.

As an aside something I would really like to see, would be scooping up and refitting the GP-B satellite and rerunning the experiment around Venus, where there would be no intrinsic magnetic field to control for. Test the same frame dragging effect under different circumstances.
« Last Edit: 09/19/2017 07:36 pm by OnlyMe »

Offline Monomorphic

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The last few days have been spent calibrating the mirrored laser displacement sensors and the dampening system. I switched from antifreeze to light vegetable oil as it provided more dampening and is non-toxic. I was using the entire paddle with the antifreeze, while now I use a smaller portion. This means I can now adjust from over to under damped and here are two example calibration coil pulse tests. The pulse from today was 5.76uN as I added a 2.7ohm resistor to get the current down to 1A from 2.6A. But I think I still need a capacitor to keep the voltage steady.   
« Last Edit: 09/19/2017 07:55 pm by Monomorphic »

Offline Rodal

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The last few days have been spent calibrating the mirrored laser displacement sensors and the dampening system. I switched from antifreeze to light vegetable oil as it provided more dampening and is non-toxic. I was using the entire paddle with the antifreeze, while now I use a smaller portion. This means I can now adjust from over to under damped and here are two example calibration coil pulse tests. The pulse from today was 5.76uN as I added a 2.7ohm resistor to get the current down to 1A from 2.6A. But I think I still need a capacitor to keep the voltage steady.



Quote
Compared to No. 2 diesel fuel, all of the vegetable oils are much more viscous, are more reactive to oxygen, and have higher cloud point and pour temperatures
Jones, Samuel T.; Peterson, Charles L.; Thompson, Joseph C. Biological and Agricultural Engineering Department, University of Idaho, Moscow, Idaho, USA. “Used Vegetable Oil Fuel Blend Comparisons Using Injector Coking in a DI Diesel Engine.” Presented at 2001 ASAE Annual International Meeting, Sacramento,California, USA, July 30–August 1, 2001.


Low temperature oxidation of oil

Figure 13 Comparison of anisidine value profiles of several vegetable oils during oxidation at 70°C in a convection oven with the exposure to the circulating air (Guillén & Cabo 2002).

[Anisidine value test is used to assess the secondary oxidation of oil or fat, which is mainly imputable to aldehydes and ketones, and is therefore able to tell the oxidation “history” of an oil or a fat. Furthermore, AnV analysis on oil is an indicator of excessive oil deterioration in deep frying process.]

https://firesciencereviews.springeropen.com/track/pdf/10.1186/2193-0414-1-3?site=firesciencereviews.springeropen.com




Antifreeze



http://www.viscopedia.com/viscosity-tables/substances/automotive-antifreeze/
« Last Edit: 09/19/2017 08:44 pm by Rodal »

Offline Monomorphic

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Compared to No. 2 diesel fuel, all of the vegetable oils are much more viscous, are more reactive to oxygen, and have higher cloud point and pour temperatures

I'm using soybean oil right now, but that is easy to change. I need something with a viscosity between antifreeze and vegetable oil. #2 diesel fuel looks promising as well as other fuel oils.
« Last Edit: 09/19/2017 08:45 pm by Monomorphic »

Offline Rodal

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Compared to No. 2 diesel fuel, all of the vegetable oils are much more viscous, are more reactive to oxygen, and have higher cloud point and pour temperatures

I'm using soybean oil right now, but that is easy to change. I need something with a viscosity between antifreeze and vegetable oil. #2 diesel fuel looks promising as well as other fuel oils.
was not advocating to use diesel fuel (*), it was just there in the viscosity vs temperature chart for sunflower oil  ;)

(*) Hazard Class II, Flash point=   101-140°F (39-60°C)

Here is a Material Safety Data Sheet for soybean oil http://www.sciencelab.com/msds.php?msdsId=9925064


Viscosity vs temperature for soybean oil:









« Last Edit: 09/19/2017 09:26 pm by Rodal »

Offline Monomorphic

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Mineral oil looks like it may work better than soybean. Depending on grade, its viscosity is about half at 20°C. It's cheap, widely available, and it won't evaporate at room temp.
« Last Edit: 09/19/2017 10:06 pm by Monomorphic »

Offline Rodal

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Mineral oil looks like it may work better than soybean. Depending on grade, its viscosity is about half at 20°C. It's cheap, widely available, and it won't evaporate at room temp.



« Last Edit: 09/19/2017 10:14 pm by Rodal »

Offline Monomorphic

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Actually spindle machine oil looks ideal. It is available in five "velocite" grades with the viscosity well known.
No 6. is available for $30 a gallon:

https://www.mobil.com/English-US/Industrial/pds/GLXXMobil-Velocite-Oil-No-Series

https://goo.gl/JfB7ut
« Last Edit: 09/19/2017 11:03 pm by Monomorphic »

Offline jmossman

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...
This means I can now adjust from over to under damped and here are two example calibration coil pulse tests. The pulse from today was 5.76uN as I added a 2.7ohm resistor to get the current down to 1A from 2.6A. But I think I still need a capacitor to keep the voltage steady.

Monomorphic,

Congrats on the continued progress with you build!

If you could provide a circuit diagram, some of us here on the forum may be able to provide some assistance with the calibration pulse circuit design. 

If a true constant current pulse is desired, I suspect the ideal circuit may be a little bit more involved than just adding a capacitor to a voltage divider circuit.  (although I suspect the primary requirement is merely a reproducable current/voltage profile during the calibration pulse)

Best regards,
James

Offline flux_capacitor

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Someone finally translated Dr Chen Yue's recent interview on CCTV in English. Not perfect but much better than Google's automatic gibberish translation.
You will not discover much, other than the fact CAST seems at the vey beginning of this research and they do not even know if it could work. To me, this is an attempt to make a propellantless RF resonant cavity thruster, but is has little to do with Shawyer's EmDrive, which is a very high-Q frustum resonant cavity with spherically shaped end plates, whereas this one is a flat cylinder with some slits and diaphragms at the bottom interior part.


Offline kamill85

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Utterly and completely wrong. Any information travelling faster than light would allow for sending messages to the past. See the FTL paradox thread for details.

Whatever they said aside, I thought we've been through this, meberbs... You cannot sent messages "to the past" with Apparent FTL, it can only appear so to an observer. Traveling to actual location would reveal that whatever was seen, was ultimately a lie. Light/information that Observer can intercept can make him come to a conclusion that if he travels to a location X to tell this "message from the future", causality will be broken, but if you do the transformations correctly, it turns out upon arrival the time would be in the future of the said event. I only looks like messages can be sent to the past (and only from one frame of reference), but it wont work that way.

-----

Another thing, could someone jump in and explain the effect I witnessed personally today. I was boiling some water in a kettle, water around here is very hard, hence there is considerable "stone" buildup in a short period of time. Kettle was full, 3.5L, made out of stainless steel, so everything was quite heavy. Anyway, during heating, I assume around 90'C, there was an "explosion" inside, those happen quite often when a bubble wants to burst beneath a quite thick layer of the "stone". The kettle moved to the side, probably 2-3cm. There was no exhaust hence my question: what could possibly be the mechanics behind this event? I'm not asking because my kettle is pretty much EM Drive cavity-shaped by the way ;D - it was just quite strange to see...
« Last Edit: 09/19/2017 11:38 pm by kamill85 »

Online meberbs

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Utterly and completely wrong. Any information travelling faster than light would allow for sending messages to the past. See the FTL paradox thread for details.

Whatever they said aside, I thought we've been through this, meberbs... You cannot sent messages "to the past" with Apparent FTL, it can only appear so to an observer. Traveling to actual location would reveal that whatever was seen, was ultimately a lie. Light/information that Observer can intercept can make him come to a conclusion that if he travels to a location X to tell this "message from the future", causality will be broken, but if you do the transformations correctly, it turns out upon arrival the time would be in the future of the said event. I only looks like messages can be sent to the past (and only from one frame of reference), but it wont work that way.
Yes, I thought we went over this, and the method of FTL does not matter. Wormholes, warp bubbles and other such concepts that have the ship maintain a local slower than light speed still break causality. You can see this plainly from the Lorentz transformations which apply in the flat space that remains after the warp drive is turned off, and existed before it was turned on. Talking about "looks" is irrelevant, because none of the causality breaking situations described in the FTL thread involve discussing the apparent order of events by an observer measuring signals that are light delayed, but instead use knowledge of the situation to calculate the actual times and positions of events.

You never responded to my last post to you in the FTL thread. This conversation should continue there to reduce the clutter in this thread if you want to continue waving your hands and pretending that it isn't an issue when you don't want it to be.

Offline Monomorphic

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If you could provide a circuit diagram, some of us here on the forum may be able to provide some assistance with the calibration pulse circuit design. 

If a true constant current pulse is desired, I suspect the ideal circuit may be a little bit more involved than just adding a capacitor to a voltage divider circuit.  (although I suspect the primary requirement is merely a reproducable current/voltage profile during the calibration pulse)

Right now it is very simple so I haven't bothered to draw it up. The calibration coil and supply wires are 2.2ohm. I am using a 5V 2A power supply to energize the coil.  The coil was getting hot and the pulse was too strong so I added a 2.6ohm 10W resistor in series with the coil to bring resistance up to ~5ohm and the current down to ~1A. On/off is controlled via a separately powered relay switch so it can be toggled from two different locations.

The current/voltage profile is reproducible now, but if you look closely, there is still a small increase in voltage.  It would be nice if both were regulated and constant throughout the 30 second pulse.     
« Last Edit: 09/20/2017 12:51 am by Monomorphic »

Offline spupeng7

Someone finally translated Dr Chen Yue's recent interview on CCTV in English. Not perfect but much better than Google's automatic gibberish translation.
You will not discover much, other than the fact CAST seems at the vey beginning of this research and they do not even know if it could work. To me, this is an attempt to make a propellantless RF resonant cavity thruster, but is has little to do with Shawyer's EmDrive, which is a very high-Q frustum resonant cavity with spherically shaped end plates, whereas this one is a flat cylinder with some slits and diaphragms at the bottom interior part.



flux_capacitor,

the advantages of this design are; simplicity of design and production, low mass and reduced overall volume and stackability and it may yet be found to have other advantages as a resonator, hopefully a high Q.

Either way it clearly is an emdrive, which is Shawyer's invention.
« Last Edit: 09/20/2017 02:02 am by spupeng7 »
Optimism equals opportunity.

Offline spupeng7

...You ask for an explanation of inertia differing from that which you accept...
An explanation of inertia that I accept?  On the contrary, I asked for experiments confirming the opinions expressed in the last few pages.  For all the spilled ink in expressing subjective opinions (unsupported by experimental evidence) nobody has come up with a single experiment confirming any of those opinions.  The fact is that there is no experiment showing any "Machian effect" not already present in Einstein's General Relativity.   On the contrary, all the experiments (since the 1960's, trying to confirm Brans-Dicke's theory) looking for such Machian effects have failed to find any such evidence of Machian effects not present in Einstein's GR.   Coalescence of black holes is calculated nowadays analytically and numerically using General Relativity and the results (gravitational waves including the kick of a binary black hole with accompanying star cluster out of its galaxy) are in excellent agreement with General Relativity. 

If anybody thinks that Mach's principle has anything to add to General Relativity that is lacking in General Relativity, please cite experiments supporting such opinion, and explain what is missing in General Relativity that is present in Mach's principle and cite experimental support for any such claim.

Rodal,

the flaw in GR is quantum mechanics. Why is this so hard for you to accept? GR relies on the assumption that mass has inertia, due to some undefined internal mechanism, without any explanation as to why that inertia varies with the degree of time dilation that it exists within relative to the greater universe. The experiment that calls GR into question is the emdrive itself, which defies explanation within GR.

Mach simply asked the question, what if inertia is an interaction with the wider universe, and I have given you an outline for a mechanism by which that is feasible. Of course you reject it, you are invested in your own truth, as we all are. I admire your skills and wish that I could focus them on my solution but I doubt that will happen because my notions are insulting to academia. Truth is I do not think GR is flawed, it describes time dilation and its effects beautifully, it is just incomplete in that it fails to include charge interaction as a mechanism driven by time dilation, which it obviously is.

That inclusion would allow a deep simplification of the math of relativity. That inclusion would allow a Machian explanation for inertia which does not rely on the magical thinking which the co-existence of GR and quantum mechanics currently relies upon. That inclusion would allow an explanation for emdrive thrust which is what we strive for here on this thread. Please consider.
Optimism equals opportunity.

Offline M.LeBel

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If you could provide a circuit diagram, some of us here on the forum may be able to provide some assistance with the calibration pulse circuit design. 

If a true constant current pulse is desired, I suspect the ideal circuit may be a little bit more involved than just adding a capacitor to a voltage divider circuit.  (although I suspect the primary requirement is merely a reproducable current/voltage profile during the calibration pulse)

Right now it is very simple so I haven't bothered to draw it up. The calibration coil and supply wires are 2.2ohm. I am using a 5V 2A power supply to energize the coil.  The coil was getting hot and the pulse was too strong so I added a 2.6ohm 10W resistor in series with the coil to bring resistance up to ~5ohm and the current down to ~1A. On/off is controlled via a separately powered relay switch so it can be toggled from two different locations.

The current/voltage profile is reproducible now, but if you look closely, there is still a small increase in voltage.  It would be nice if both were regulated and constant throughout the 30 second pulse.   

A switch mode power supply would eliminate line fluctuations (brownouts). With proper RF ferrite blocks on the leads and a clipping diode across the coil to prevent back EMF in the leads. One way to prepare and warm up the power supply would be to send the power to a 5 ohm dummy load and, when warmed up and ready, toggle to the coil for calibration, thereby removing the warm up effect. ???

 
« Last Edit: 09/20/2017 02:50 am by M.LeBel »

Offline tchernik

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flux_capacitor,

the advantages of this design are; simplicity of design and production, low mass and reduced overall volume and stackability and it may yet be found to have other advantages as a resonator, hopefully a high Q.

Either way it clearly is an emdrive, which is Shawyer's invention.

Yep, this puts all the comments about Chen Yue's work being about ionic thrusters (but somehow lost in translation) to rest.

This is an Emdrive, in the sense of being an asymmetric microwave resonant cavity (not in shape, but probably in its electromagnetic properties) which supposedly provides some thrust.

And they are indeed looking forward to test and use it in space.

Thus I presume there has been a track of ground based tests already.

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