-
#1580 by chongma on 13 Oct, 2016 15:28
-
This has undoubtedly been mentioned before and probably doesn't go very far towards explaining how the emdrive really works. But if the emdrive does work the double slit experiment could offer an explanation. If individual photons shot through slits can interfere with waves and or particles that are not "present" during the experiment then perhaps the resonance pattern is causing a wave which takes advantage of or pushes against this unseen interference. Or is that what a quantum vacuum is?
-
#1581 by Gilbertdrive on 13 Oct, 2016 15:34
-
Dear Traveller
You claimed several times that the experiments were in favour of the constant thrust for constant input power.
I personally claim that there is no experimental evidence for thrust bigger than Pi/V where Pi is the input Power, and V the speed of the frustum in the laboratory reference frame. I do not claim that it is a true limit, I just claim that there is still no experiment that shows more thrust.
For example, for a speed V=3km/s the maximum thrust predicted by my formula is 333mN/Kw (this one is also indicated by Shawyer)
For a speed of V=300m/s the maximum thrust is 3,333N/Kw
For a speed of V=3m/s the maximum thrust is 333,33 N/Kw
For a speed of 1 m/s the maximum thrust is 1000N/Kw (much, is not it ?)
For a speed of 1cm/s the maximum thrust is 100 000N/Kw...
For a speed of 0 m/s there is no limit to the maximum thrust.
Does any experiment show a stronger force that the maximum predicted by my formula ?
What was the higher force measured by a rotary rig ? at what speed ?
In his later papers, Roger stated his earlier statements on velocity reducing thrust were incorrect and he withdrew them.
As far as I know, no rotary test rig has even started to get to those values. Long way away.
Thanks very much for the information. The point that Shawyer has retracted older statements is very important. In what document did it clearly ?
Also, the fact that there is no experimental evidence that the thrust can be superior to Pi/V is very important about possible theories of how the drive works. In fact, if the thrust was superior to Pi/V, it should dismiss many possible theories. -
#1582 by TheTraveller on 13 Oct, 2016 15:38
-
This has undoubtedly been mentioned before and probably doesn't go very far towards explaining how the emdrive really works. But if the emdrive does work the double slit experiment could offer an explanation. If individual photons shot through slits can interfere with waves and or particles that are not "present" during the experiment then perhaps the resonance pattern is causing a wave which takes advantage of or pushes against this unseen interference. Or is that what a quantum vacuum is?
Then again it could transfer some of the EmWave momentum to the cavity, thus preserving CofM.
Where is it written by the gods of existence that the only way to transfer momentum between EmWave and mass is via the EmWave to bounce /reflect off the mass and leave some momentum behind? Sure that is all we have seen to date, well until Roger came along and discovered another way to transfer momentum from EmWave to mass. -
#1583 by TheTraveller on 13 Oct, 2016 15:45
-
Thanks very much for the information. The point that Shawyer has retracted older statements is very important. In what document did it clearly ?
IAC 2013 paper as attached.
-
#1584 by bmcgaffey20 on 13 Oct, 2016 15:51
-
Roger always said refer to GR to explain the device...
E=MC^2 and also M=E/C^2. The charged cavity has mass and we are exploiting the charging and discharging and more specifically the direction of the artificially produced gravitational field??? The higher the Q, the more energy content of the charged cavity... if so then the project scales -
#1585 by Rodal on 13 Oct, 2016 15:53
-
Roger always said refer to GR to explain the device...
Shawyer has always claimed that all that is required is Special Relativity (not General Relativity) and , Maxwell's equations, and Newton's third law. He is on videotape saying this. If you disagree, please show a reference where Shawyer ever invokes General Relativity. Thanks
E=MC^2 and also M=E/C^2. The charged cavity has mass and we are exploiting the charging and discharging and more specifically the direction of the artificially produced gravitational field??? The higher the Q, the more energy content of the charged cavity... if so then the project scales
-
#1586 by rfmwguy on 13 Oct, 2016 15:58
-
This has undoubtedly been mentioned before and probably doesn't go very far towards explaining how the emdrive really works. But if the emdrive does work the double slit experiment could offer an explanation. If individual photons shot through slits can interfere with waves and or particles that are not "present" during the experiment then perhaps the resonance pattern is causing a wave which takes advantage of or pushes against this unseen interference. Or is that what a quantum vacuum is?
Take a look at the focal point of the small diameter end, beyond the physical plane of the large diameter. Assume there is such a thing as quantum entanglement. Look up type II photons. Study the conditions required to create entanglement. Think you'll be on your way to developing a good theory. Your "interference" reference got my attention. Good luck... -
#1587 by bmcgaffey20 on 13 Oct, 2016 15:58
-
A response from THE man himself. Very prompt too. You must be watching these forums very closely!
So you are saying the device doesn't scale? lol. btw-- thank you for correcting me, I thought I had a eureka moment in understanding the device. Obviously, less than amateur enthusiast here!! -
#1588 by Rodal on 13 Oct, 2016 16:03
-
A response from THE man himself. Very prompt too. You must be watching these forums very closely!
Maybe General Relativity is involved and your Eureka moment is correct. General Relativity (and several other possible effects) would make this an open system, which would nullify all the conservation of energy arguments being made in NSF pages that deal with conservation of energy as a closed system and ignore General Relativity gravitational effects (or other gravitational theories like Brans-Dicke or Hoyle-Narlikar).
So you are saying the device doesn't scale? lol. btw-- thank you for correcting me, I thought I had a eureka moment in understanding the device. Obviously, less than amateur enthusiast here!!
The conservation of energy arguments being made would be like somebody claiming that a Gravity Assist maneuver is impossible, because a spacecraft considered as a closed system, where gravity is ignored, would be breaking conservation of energy in a swing-by maneuver.
I just wanted to clarify what Shawyer maintains, and in no way do I now or I have ever agreed with Shawyer's explanation that a closed microwave cavity can self-accelerate purely based on Special Relativity, Maxwell's equations and Newton's third law.
-
#1589 by bmcgaffey20 on 13 Oct, 2016 16:06
-
Well... that would be wonderful now wouldn't it? How profound the implications might be.
-
#1590 by TheTraveller on 13 Oct, 2016 16:09
-
A response from THE man himself. Very prompt too. You must be watching these forums very closely!
Maybe General Relativity is involved and your Eureka moment is correct. General Relativity (and several other possible effects) would make this an open system, which would nullify all the conservation of energy arguments being made in NSF pages that deal with conservation of energy as a closed system and ignoring gravitational effects.
So you are saying the device doesn't scale? lol. btw-- thank you for correcting me, I thought I had a eureka moment in understanding the device. Obviously, less than amateur enthusiast here!!
The conservation of energy arguments being made would be like somebody claiming that a Gravity Assist maneuver is impossible, because a spacecraft considered as a closed system, where gravity is ignored, would be breaking conservation of energy in a swing-by maneuver.
I just wanted to clarify what Shawyer maintains, and in no way do I now or I have ever agreed with Shawyer's explanation
http://emdrive.com/faq.htmlQuote2.
Q. How can a net force be produced by a closed waveguide?
A. At the propagation velocities (greater than one tenth the speed of light) the effects of special relativity must be considered. Different reference planes have to be used for the EM wave and the waveguide itself. The thruster is therefore an open system and a net force can be produced. -
#1591 by Rodal on 13 Oct, 2016 16:12
-
...
Yes, again, he continues to claim only Special Relativity and not General Relativity. He does not specify what makes it an open system (what external fields is he considering ?)
http://emdrive.com/faq.htmlQuote2.
Q. How can a net force be produced by a closed waveguide?
A. At the propagation velocities (greater than one tenth the speed of light) the effects of special relativity must be considered. Different reference planes have to be used for the EM wave and the waveguide itself. The thruster is therefore an open system and a net force can be produced. -
#1592 by bmcgaffey20 on 13 Oct, 2016 16:19
-
Well if this is the case... Higher energy photons should have a greater affect. And if that holds to be true, we may one day have a super emdrive. Imagine, an emdrive with photon energies as dense as the xray and gamma spectrum.
-
#1593 by wicoe on 13 Oct, 2016 16:25
-
The formula would become in a upper stage only version
"the increase of Kinetic energy of the upper stage equals the chemical energy delivered by it's own fuel burnt less the total kinetic energy gained by the propellant, and less the energy lost as waste heat.
This increase of Kinetic energy of the upper stage can be superior to the chemical energy spent, if the propellant onboard the upper stage has lost more kinetic energy than the losses as waste heat."
The upper stage is still a rocket (just a smaller one), so all you have to do is change the reference frame so that the rocket is already moving at t0. However, changing the reference frame does not change the formula:
"The increase of kinetic energy of a rocket (or the upper stage, which is still a rocket) equals the chemical energy delivered by its own fuel burnt less the total kinetic energy gained (has to be read as "lost" if negative) by the propellant, and less the energy lost as waste heat".
I realize that you just wanted to slightly change the language so that it better fits the upper stage case, and it's understood that the underlying mathematical formula is the same. If anyone needs a detailed mathematical explanation, here it is (for both ref frames).
Let's assume that dt is our time interval, m is the mass of the propellant burnt between t0 and t0+dt, M is the mass of the rocket (not including m!), and dVp and dVr are the resulting velocity increases of the propellant and the rocket (absolute values). In the ref frame co-moving with the rocket at t0, the kinetic energy increase of the rocket (dKr) will be MdVr^2/2, and the kinetic energy increase of the propellant (dKp) will be mdVp^2/2. If you add these values together (dK = dKr+dKp = MdVr^2/2 + mdVp^2/2), you'll get the chemical energy burnt less the energy wasted as heat.
Now let's switch to the reference frame of the earth, and let's assume that the rocket is already moving relative to the earth (at t0), and has the speed of U. The kinetic energy increase of the rocket (dKr) will be M(U+dVr)^2/2 - MU^2/2. The kinetic energy increase of the propellant (dKp) will be m(U-dVp)^2/2 - mU^2/2. Let's add these values together: dK = dKr+dKp = M(U+dVr)^2/2 - MU^2/2 + m(U-dVp)^2/2 - mU^2/2 = MU^2/2 + MUdVr + MdVr^2/2 - MU^2/2 + mU^2/2 - mUdVp + mdVp^2/2 - mU^2/2 = MdVr^2/2 + mdVp^2/2 + (MUdVr - mUdVp). Now, since momentum is conserved as well, MdVr = mdVp, and you get the same result as in the co-moving reference frame: dK = MdVr^2/2 + mdVp^2/2, which corresponds to the chemical energy burnt less the energy wasted as heat. -
#1594 by TheTraveller on 13 Oct, 2016 16:31
-
Well if this is the case... Higher energy photons should have a greater affect. And if that holds to be true, we may one day have a super emdrive. Imagine, an emdrive with photon energies as dense as the xray and gamma spectrum.
10,000N/kWrf or 1,000kg/kWrf is not enough? -
#1595 by bmcgaffey20 on 13 Oct, 2016 16:46
-
Well if this is the case... Higher energy photons should have a greater affect. And if that holds to be true, we may one day have a super emdrive. Imagine, an emdrive with photon energies as dense as the xray and gamma spectrum.
10,000N/kWrf or 1,000kg/kWrf is not enough?
Why have billions..... when you can have..... MILLIONS??? #evilgrin
All kidding aside, if you can achieve 10,000N/kwRf with the microwave spectrum perhaps the inverse of what I am saying is applicable. Using a less energetic photon spectrum would give us a new way to test for the affect with a different photon source. If the affect can be confirmed with other photon sources it may give us a base to go on for scalability and testing of different shapes and modes without burning up devices. -
#1596 by wicoe on 13 Oct, 2016 16:51
-
An EmDrive generates 2 forces that can be measures but not at the same time nor with the same test setup:
1) Thrust force with a vector small to big that is the result of the differential radiation pressure on the end plates. This is a static force that can be measured with a scale.
2) Reaction force with a vector big to small and is the equal but opposite force to the Thrust force. This is a dynamic force and can only be measured during free acceleration.
Roger has measured both forces and has shown that they are approx equal in force amplitude but opposite in force vector direction.
A force is a measure of interaction between objects (can be manifested through fields but it's essentially the same). So in order to describe a force, you need to specify the objects that are pushing/pulling on each other (object A and object B). Also, any force is bi-directional: if you swap the objects, you get reaction force, acting in the opposite direction. Let's assume (for a moment) that there really is a differential radiation pressure inside the EmDrive. This means that the "thrust force" results from the the photons "pushing" on the cavity wall in the direction of the higher pressure. Of course there is also a reaction force, i.e. cavity wall "pushing back" on the photons (or, to be more exact, on the source of the photons). The "action" and "reaction" forces are of exactly the same in value. A reaction force cannot cause the acting object to move in the direction of this force. If you point a laser to a mirror, it will not start moving towards you, it will start moving away from you. -
#1597 by Gilbertdrive on 13 Oct, 2016 16:55
-
Yes, that is because I wanted the clearest possible formulation about upper stage. It is also because I wanted the formula to be applicated directly, without a referential change, even if the speed of the rocket is not zero at the begining. That is why the use of "Kinetic energy increase" instead of "Kinetic energy"
The upper stage is still a rocket (just a smaller one), so all you have to do is change the reference frame so that the rocket is already moving at t0. However, changing the reference frame does not change the formula:
"The increase of kinetic energy of a rocket (or the upper stage, which is still a rocket) equals the chemical energy delivered by its own fuel burnt less the total kinetic energy gained (has to be read as "lost" if negative) by the propellant, and less the energy lost as waste heat".
I realize that you just wanted to slightly change the language so that it better fits the upper stage case, and it's understood that the underlying mathematical formula is the same. If anyone needs a detailed mathematical explanation, here it is (for both ref frames).
The aim is to use directly the formula in the earth reference frame, without having to refer to the reference frame of the stage separation.
But, yes, it is exactly your formula, no new math beside. Just a slightly different formulation, hoping that it makes the things very clear about this solved paradox of upper stage. (Once your formula is understood, there is no paradox, no problem about CoE and upper stage) -
#1598 by Monomorphic on 13 Oct, 2016 16:55
-
Well if this is the case... Higher energy photons should have a greater affect. And if that holds to be true, we may one day have a super emdrive. Imagine, an emdrive with photon energies as dense as the xray and gamma spectrum.
10,000N/kWrf or 1,000kg/kWrf is not enough?
Why have billions..... when you can have..... MILLIONS??? #evilgrin
All kidding aside, if you can achieve 10,000N/kwRf with the microwave spectrum perhaps the inverse of what I am saying is applicable. Using a less energetic photon spectrum would give us a new way to test for the affect with a different photon source. If the affect can be confirmed with other photon sources it may give us a base to go on for scalability and testing of different shapes and modes without burning up devices.
X-rays and gamma have wavelengths on the order of nanometers and picometers. Low order resonant cavities for hard x-rays and gamma rays would be the size of atoms or smaller.
We could conceivably construct Infrared emdrives 2000nm in length, but that would require MEMS and/or nanotech. -
#1599 by Bob012345 on 13 Oct, 2016 17:03
-
I find the explanation that in fact EMDrive doesn't work a lot more plausible, but to each his own.
Well it does work as you will soon see when the EW paper is released. So not believing is not a simple fix way out.
OK, let me try to rephrase... I find the explanation that "the apparent thrust observed in the tests that have been conducted so far is attributed to some natural error factor that has not yet been taken into account properly" a lot more plausible.
There are no unaccounted errors in the EW vac tests The identified errors are VERY low. Time to stop grasping at straws and deal with the reality the EmDrive works.
BTW have you read Roger's two very detailed engineering reports? If not you should as you will after the EW paper is out.
It is time to start reading what Roger has published as a start to understand the reality of the EmDrive.
Shawyer's data clearly implies that spurious effects are not driving the data since these effects would very likely have very different behavior.
