-
#2440 by demofsky on 10 Feb, 2017 02:00
-
To understand the argument that I am proposing, it is helpful to have a background in Aerodynamics and Heat Transfer. I understand that it may be difficult to grasp immediately. I don't have the time to write a formal paper on this at the moment.
It is interesting that this argument fully explains the focus that Shawyer has on his cut-off rule, and his preference for TE013.
See this for example to understand the mechanisms involved, although this paper is not exactly analogous to what I am proposing:
https://web.ics.purdue.edu/~ardekani/pdf/PRL_2014.pdf
This seems as if this should be very easy to test for. Just a bit of smoke or a few lightweight streamers in front of either end unless I am missing something. -
#2441 by Rodal on 10 Feb, 2017 02:16
-
This analysis in the last few pages is effective at demonstrating this because the analyst calculates and displays the heat surface losses in W/m^2
-------------------
The truncated cone shown below will be much more effective than the shape at the bottom of the post to heat the external air asymmetrically, hence giving "propulsion by thermal convection of external air":
0.0033 W/m^2
than this one, it has less than 1/6 of the heating power to heat the air next to the small end:
only 0.00054 W/m^2
and to make it even worse, this one is symmetric ! (the other end gets just as hot) -
#2442 by sanman on 10 Feb, 2017 04:46
-
This analysis in the last few pages is effective at demonstrating this because the analyst calculates and displays the heat surface losses in W/m^2
-------------------
The truncated cone shown below will be much more effective than the shape at the bottom of the post to heat the external air asymmetrically, hence giving "propulsion by thermal convection of external air":
450 W/m^2
Is that a fair comparison when the lower paraboloid shape looks much shorter than the truncated cone frustum shape? Suppose the paraboloid shape had been taller, like the truncated cone frustum shape above it? -
#2443 by LowerAtmosphere on 10 Feb, 2017 07:42
-
Torustrum
Very interesting. Reminded me of a Tokomak and got me thinking.
A Poynting vector illustration for the inside of this cavity geometry (and inside the torus aperture) would be very helpful and if this design produces more or less thrust, it may also help disprove certain hypotheses for operation such as MiHSC. The majority of the magnetic flux will be centered on the aperture of the torus, however I am very curious which way the current would flow on the outside/interior of the walls versus the interior cavity skin; will we see a dynamo effect, what about ionizing gain medium to create oscillating plasma streams? Plus where would induced voltages and Lenz's law play in, given the difference in interior versus exterior generated fields? Doesn't the aperture effectively acts as a copper coil in this situation due to the change in energy density?
Perhaps a tapered conical torus (fat ice cream cone)
or a ball bearing
or a rotated right(or other) angled triangle
design could also be simulated?
-
#2444 by OttO on 10 Feb, 2017 07:47
-
Just some comments about the current discussion:
1- It is why we want to test the frustum within an airtight and thermal insulated shell.
2- It is why we want to test a frustum with all the test thingies attached but powered OFF and with heating resistors of the appropriate power ON.
3- And yes incense stick cost a dime... -
#2445 by RERT on 10 Feb, 2017 10:49
-
Monomorphic -
Awesome test rig! I know praise from a guy who needs a manual to use a screwdriver isn't much, but well done!
A couple of things occur:
1) Are you happy with the screen/computer on the torsional balance? Will it generate heat, and does it matter?
2) Your tap-tests show great regularity in the rest rig response to an impulse. Another test which might be useful would be to apply a force for an extended period, and watch the pendulum move as you apply the force and after it is terminated. You could then compare the response curve to the response under frustrum power for the same period, to help understand how beam dynamics affect the output data. -
#2446 by RERT on 10 Feb, 2017 11:04
-
Guys - re: cut-off, convection, etc...
I think it's plain that Dr. Rodal is correct in principle, in that heat at one end might induce asymmetric airflow which could create horizontal forces by the Bernoulli effect.
However, the data from Eagleworks shows a response in vacuum essentially the same as in air. There are still thermal effects in both cases, but convection can't be the dominant effect, at least in their setup.
Convective flow outside the frustrum is easy to experiment for: an expanded polystyrene insulator covering the small end can drastically change the thermal properties of the rig. If it doesn't change any anomalous force, then it isn't that kind of convection.
Let's wait for some data (from Monomorphic): there may be nothing to explain, or convection might be crazy or interesting, dependent on context. -
#2447 by Rodal on 10 Feb, 2017 12:04
-
Guys - re: cut-off, convection, etc...
I think it's plain that Dr. Rodal is correct in principle, in that heat at one end might induce asymmetric airflow which could create horizontal forces by the Bernoulli effect.
However, the data from Eagleworks shows a response in vacuum essentially the same as in air. There are still thermal effects in both cases, but convection can't be the dominant effect, at least in their setup.
Convective flow outside the frustrum is easy to experiment for: an expanded polystyrene insulator covering the small end can drastically change the thermal properties of the rig. If it doesn't change any anomalous force, then it isn't that kind of convection.
Let's wait for some data (from Monomorphic): there may be nothing to explain, or convection might be crazy or interesting, dependent on context.
Don't forget that TT was in previous threads criticizing NASA and Tajmar's measurements as being "snowflake" forces compared with the forces claimed by Shawyer (several orders of magnitude times greater)
Many things are possible. It maybe that the 0.174 Newtons claimed by Shawyer for the Boeing Flight Thruster is due to external asymmetric thermal convection, while, on the other hand, that NASA's measurement of 0.0000099 Newtons for TM212 in reverse and 0.000055 Newtons for TM212 forward are really anomalous. (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1327012#msg1327012 )
That may explain that when Boeing tested Shawyer's Flight Thruster in a vacuum chamber, a Boeing engineer stated they "got nothing" (as it was reported at Estes park ).
Maybe the disparity (between Shawyer and Boeing) is due to Shawyer never testing his devices in a vacuum, and Boeing expecting to measure 0.174 Newtons in a vacuum, that was claimed by Shawyer. Remember that the purpose of the Boeing contract was to test the EM Drive in Space, in vacuum, and that Shawyer had not tested in vacuum. It is possible that Boeing set up the measurement system to measure 0.174 Newtons, and could not measure NASA-Type-Forces like 0.000055 Newtons, thus stating they got "nothing", and then not proceeding to spend the much greater amount of money to test in orbit.
Please take into account the huge disparity (several orders of magnitude) between the forces claimed by Shawyer and the forces measured by NASA and by Tajmar in vacuum.
There is a huge disparity between the force measurements claimed by Shawyer and those by NASA.
There is a lot of confusion out there regarding the force that was measured in EM Drive experiments. For example there is an EM Drive builder that conducted experiments in his garage that recently (Feb 6 2017 show) appeared in TMRO stating that NASA had measured 1.2 milliNewtons force and also wrote this here in posts, this had to be corrected at NSF by Paul March stating that he only wished that would be so, as the force that NASA measured was more than an order of magnitude smaller than what was reported at TMRO.
----------
EDIT: Also, the NASA EM Drive is peculiar in that, unlike Shawyer's EM Drive that has the metal at the small and big ends directly in contact with the air, NASA uses an epoxy composite layer that acts as a thermal insulator, having a very thin copper layer on the inside surface, so that the epoxy composite thermally insulates the exterior.
FR-4 PCB 0.063 inches thick with a very thin layer (35 microns thick) layer of copper on the inside
This may result in much smaller thermal convection in NASA's experiments than in Shawyer's experiments.
Thermal conductivity through the plane of FR-4 0.29 W/(m·K)
Thermal conductivity copper 385.00 W/(m·K)
The copper used by Shawyer has 1328 greater times thermal conductivity than the FR-4 used by NASA for the exterior surface
Most importantly, the thermal diffusivity of copper is 11*10^(-5) m^2/s compared with only 0.013 *10^(-5) m^2/s for epoxy, so copper diffuses heat almost 1000 times faster than epoxy
(Copper, as a good thermal conductor diffuses heat much faster than epoxy) -
#2448 by Monomorphic on 10 Feb, 2017 12:20
-
1) Are you happy with the screen/computer on the torsional balance? Will it generate heat, and does it matter?
The mini-computer has a pretty hefty aluminum case that is attached directly to the aluminum torsional pendulum beam. I've not seen much heat there using an IR camera. The greatest heat seems to be coming from the USB spectrum analyser - but even that is tiny and probably negligible. Heat problems are infinitesimal compared to when I was using a 600W magnetron.
As for the HD monitor, it is used mostly for set-up and calibration. It will be unpluged during tests as I will be using remote desktop from another PC to access the mini-pc. -
#2449 by rfmwguy on 10 Feb, 2017 13:38
-
I agree with you. The sidelines might talk thermal and fluid dynamics, but what you can be comfortable with is any force present will occur much faster than it will take for the assembly to reach thermal equilibrium. Hobby theorists aside, note the displacements from a cold start, then over a protracted period of time as the assembly reaches a relative thermal stability as I did. Note you have an advantage over my testing as you have a air box which will contain the heat longer than my open air testing. This will work to your advantage as better thermal management.1) Are you happy with the screen/computer on the torsional balance? Will it generate heat, and does it matter?
The mini-computer has a pretty hefty aluminum case that is attached directly to the aluminum torsional pendulum beam. I've not seen much heat there using an IR camera. The greatest heat seems to be coming from the USB spectrum analyser - but even that is tiny and probably negligible. Heat problems are infinitesimal compared to when I was using a 600W magnetron.
As for the HD monitor, it is used mostly for set-up and calibration. It will be unpluged during tests as I will be using remote desktop from another PC to access the mini-pc.
Since you worked with IR measurements, you know that copper absorbs and radiates heat slowly. Sudden displacements are not an instantaneous thermal event (oversimplification). Also, be sure to state both the absolute force displacement as well as the benchmark xx/kW, with 1kW being the reference as per the EW paper. 18.4 mN was my absolute, while 24.5 mN/kW was my benchmark:
"IT WAS previously reported that radio-frequency (RF) resonant cavities generated anomalous thrust on a low-thrust torsion pendulum [1,2] in spite of the apparent lack of a propellant or other medium with which to exchange momentum. It is shown here that a dielectrically loaded, tapered RF test article excited in the transverse magnetic 212 (TM212) mode (see Fig. 1) at 1937 MHz is capable of consistently generating force at a thrust-to-power level of 1.2 +/-0.1 mN∕kW with the force directed to the narrow end under vacuum conditions."
http://arc.aiaa.org/doi/pdf/10.2514/1.B36120
p.s. Remember, advice received can work for or against you. Use discretion
-
#2450 by RotoSequence on 10 Feb, 2017 14:07
-
I agree with you. The sidelines might talk thermal and fluid dynamics, but what you can be comfortable with is any force present will occur much faster than it will take for the assembly to reach thermal equilibrium. Hobby theorists aside, note the displacements from a cold start, then over a protracted period of time as the assembly reaches a relative thermal stability as I did. Note you have an advantage over my testing as you have a air box which will contain the heat longer than my open air testing. This will work to your advantage as better thermal management.1) Are you happy with the screen/computer on the torsional balance? Will it generate heat, and does it matter?
The mini-computer has a pretty hefty aluminum case that is attached directly to the aluminum torsional pendulum beam. I've not seen much heat there using an IR camera. The greatest heat seems to be coming from the USB spectrum analyser - but even that is tiny and probably negligible. Heat problems are infinitesimal compared to when I was using a 600W magnetron.
As for the HD monitor, it is used mostly for set-up and calibration. It will be unpluged during tests as I will be using remote desktop from another PC to access the mini-pc.
Since you worked with IR measurements, you know that copper absorbs and radiates heat slowly. Sudden displacements are not an instantaneous thermal event (oversimplification). Also, be sure to state both the absolute force displacement as well as the benchmark xx/kW, with 1kW being the reference as per the EW paper. 18.4 mN was my absolute, while 24.5 mN/kW was my benchmark:
"IT WAS previously reported that radio-frequency (RF) resonant cavities generated anomalous thrust on a low-thrust torsion pendulum [1,2] in spite of the apparent lack of a propellant or other medium with which to exchange momentum. It is shown here that a dielectrically loaded, tapered RF test article excited in the transverse magnetic 212 (TM212) mode (see Fig. 1) at 1937 MHz is capable of consistently generating force at a thrust-to-power level of 1.2 +/-0.1 mN∕kW with the force directed to the narrow end under vacuum conditions."
http://arc.aiaa.org/doi/pdf/10.2514/1.B36120
p.s. Remember, advice received can work for or against you. Use discretion
It remains hard to be sure that the initial displacement is caused by something other than lorentz forces. Even at low power, their effect can be fairly large.
-
#2451 by rfmwguy on 10 Feb, 2017 14:15
-
Which is why builders should follow the advice of potomacneuron whose paper was based on actual experimentation and not conjecture. He has been counseling just about every builder that I am aware of.
I agree with you. The sidelines might talk thermal and fluid dynamics, but what you can be comfortable with is any force present will occur much faster than it will take for the assembly to reach thermal equilibrium. Hobby theorists aside, note the displacements from a cold start, then over a protracted period of time as the assembly reaches a relative thermal stability as I did. Note you have an advantage over my testing as you have a air box which will contain the heat longer than my open air testing. This will work to your advantage as better thermal management.1) Are you happy with the screen/computer on the torsional balance? Will it generate heat, and does it matter?
The mini-computer has a pretty hefty aluminum case that is attached directly to the aluminum torsional pendulum beam. I've not seen much heat there using an IR camera. The greatest heat seems to be coming from the USB spectrum analyser - but even that is tiny and probably negligible. Heat problems are infinitesimal compared to when I was using a 600W magnetron.
As for the HD monitor, it is used mostly for set-up and calibration. It will be unpluged during tests as I will be using remote desktop from another PC to access the mini-pc.
Since you worked with IR measurements, you know that copper absorbs and radiates heat slowly. Sudden displacements are not an instantaneous thermal event (oversimplification). Also, be sure to state both the absolute force displacement as well as the benchmark xx/kW, with 1kW being the reference as per the EW paper. 18.4 mN was my absolute, while 24.5 mN/kW was my benchmark:
"IT WAS previously reported that radio-frequency (RF) resonant cavities generated anomalous thrust on a low-thrust torsion pendulum [1,2] in spite of the apparent lack of a propellant or other medium with which to exchange momentum. It is shown here that a dielectrically loaded, tapered RF test article excited in the transverse magnetic 212 (TM212) mode (see Fig. 1) at 1937 MHz is capable of consistently generating force at a thrust-to-power level of 1.2 +/-0.1 mN∕kW with the force directed to the narrow end under vacuum conditions."
http://arc.aiaa.org/doi/pdf/10.2514/1.B36120
p.s. Remember, advice received can work for or against you. Use discretion
It remains hard to be sure that the initial displacement is caused by something other than lorentz forces. Even at low power, their effect can be fairly large. -
#2452 by Fan Boi on 10 Feb, 2017 14:23
-
If this is a thermal affect, would testing this in ambient air that was maybe 20 or 30 degrees below zero enhance the affect? It might take a while to warm up the device but wouldn't a greater temperature differential make thermal movements greater? Maybe someone in Alaska might test in their garage, or maybe someone could set one up in a large walk-in freezer. Just a thought.
-
#2453 by RotoSequence on 10 Feb, 2017 14:25
-
It remains hard to be sure that the initial displacement is caused by something other than lorentz forces. Even at low power, their effect can be fairly large.
Which is why builders should follow the advice of potomacneuron whose paper was based on actual experimentation and not conjecture. He has been counseling just about every builder that I am aware of.
I'm not looking to heckle you and your fellow builders from the peanut gallery. I want this to work, but proving an anomalous force, which should be the end goal of these endeavors, is difficult. Every non-thrusting element contributing to the force measurements, at least as a whole and ideally in each part, needs to be understood and characterized to the same degree of precision as the claimed thrust to eliminate the possibility that there are uncharacterized, but ordinary forces at work. -
#2454 by rfmwguy on 10 Feb, 2017 14:31
-
If this is a thermal affect, would testing this in ambient air that was maybe 20 or 30 degrees below zero enhance the affect? It might take a while to warm up the device but wouldn't a greater temperature differential make thermal movements greater? Maybe someone in Alaska might test in their garage, or maybe someone could set one up in a large walk-in freezer. Just a thought.
It was my thought to conduct the data runs from cold start to full warm-up. Roughly speaking, the full warm-up period on the magnetron and copper was only about 20 minutes according to the IR readings of the mag core and cavity. There was little to no thermal conductivity from the cavity or power supply wires to the beam.
Very low temperatures are reported to increase Q and thus, the EmDrive force, but this is at cryogenic temperatures. I'd just suggest the simpler the thermal management the better. Monomorphic is making an improvement in testing by confining ambient to a much smaller physical area. -
#2455 by aero on 10 Feb, 2017 14:39
-
Talk to SeeShells about it. She lives high in the mountains and it gets very cold in the winter. Heck, it gets very cold in the winter in much of the world.
-
#2456 by rfmwguy on 10 Feb, 2017 14:43
-
This is very true. Suffice it to say that this has been drilled into our heads for a while now both here and more "coarsely" on other forums. Believe it or not, the builders I know are well aware of the pitfalls. The key here is that EmDrive experiments are yielding much higher displacement readings than any of Woodward's efforts to date. This has been a criticism of his work along with the usefulness of microNewton thrust levels.It remains hard to be sure that the initial displacement is caused by something other than lorentz forces. Even at low power, their effect can be fairly large.
Which is why builders should follow the advice of potomacneuron whose paper was based on actual experimentation and not conjecture. He has been counseling just about every builder that I am aware of.
I'm not looking to heckle you and your fellow builders from the peanut gallery. I want this to work, but proving an anomalous force, which should be the end goal of these endeavors, is difficult. Every non-thrusting element contributing to the force measurements, at least as a whole and ideally in each part, needs to be understood and characterized to the same degree of precision as the claimed thrust to eliminate the possibility that there are uncharacterized, but ordinary forces at work.
Getting the signal up and out of the "noise" is paramount in EmDrive testing. Note that monomorphic will be increasing power one step at a time and should be able to exceed Lorentz forces as forecast by potomacneuron once he views his setup and has the voltage and current values moving through the wire harnesses.
-
#2457 by Rodal on 10 Feb, 2017 14:46
-
If this is a thermal affect, would testing this in ambient air that was maybe 20 or 30 degrees below zero enhance the affect? It might take a while to warm up the device but wouldn't a greater temperature differential make thermal movements greater? Maybe someone in Alaska might test in their garage, or maybe someone could set one up in a large walk-in freezer. Just a thought.
Talk to SeeShells about it. She lives high in the mountains and it gets very cold in the winter. Heck, it gets very cold in the winter in much of the world.
The diffusivity equations show that the temperature difference (not the absolute temperature) as a function of time is governed by the (induction heating) power input and the initial conditions. Take a look at the equations.
The induction heating power input gives you a temperature differential, a temperature increase over the reference conditions.
-
#2458 by Monomorphic on 10 Feb, 2017 14:48
-
If we want to look for asymmetric heat convection then we could use Schlieren photography.
-
#2459 by M.LeBel on 10 Feb, 2017 15:01
-
The concept of space-time is a bridge between two truth systems (both choiceless) we created in order to keep doing physics in our reality knowing well what the real universe is made of; the time process alone. Only one stuff; here is why.
It is strange for you to talk about logic, because you seem to not be able to follow basic logic at all.
Knowing that the universe is well described by maths and that maths is based on logic... it is easy to conclude that the universe works, at its most basic level, on logical operations. And a logical system may be operational on the only condition that it is all made of one type of stuff (one nature; many variations). No system containing “apples and oranges” can be operational on logic; ever.
Think about this when you shuffle your equations.
Food for thought...
Your system seems to only deal with attractive forces, when Electromagnetism (and other forces) can attract or repel based on properties like charge. There is no way to generate behavior like this from a claim "everything is made out of time." You should learn what equations we already have, so that you will realize there is no way to shuffle them to be consistent with what you are claiming.
Meberbs, I see that you understand very well my theory and that you place the highest value on its scope and power. Coming from you, it means a lot to me. The electrodynamics is coming...
Thanks,
Marcel,
