(...) the water float idea is probably the best of all for seeing thrust directly - and its dynamics. (...)
As far as I understand, with this test setup it can't be due to the air buoyancy or air heating up in general.
That 720 mN came from about 1 KW of power. The Baby EmDrive uses not kilowatts, not Watts, but milliwatts. You need to adjust your expectations accordingly.
Quote from: deltaMass on 06/11/2015 08:22 amThat 720 mN came from about 1 KW of power. The Baby EmDrive uses not kilowatts, not Watts, but milliwatts. You need to adjust your expectations accordingly.It doesn't need to float 1 ton of force for me... no need for floating cars as evidence...just a few hundreds of mN , not to be attributed to any already (thermal, magnetic, etc) known effect, would be enough, i think...
Quote from: PaulF on 06/11/2015 05:41 amQuote from: dustinthewind on 06/11/2015 01:45 amQuote from: Rodal on 06/11/2015 01:13 amDisturbing to se the EM Drive's strange preference of one direction vs. another (reminds me of the issue with NASA turning it around by 180 degrees). I have been wondering if a preferred frame means that there is a specific velocity at which it appears one should be at rest. I would suspect that this might be so. Far away from a gravity well, maybe we can assume space is stationary, and light speed is about the same in any direction from a 3rd observer displaced from all gravity. Inside a gravity well however, lets assume space time is moving into the gravity well. With a black hole, at the event horizon lets say, space is moving in at the speed of light. At that point light cant escape because space is moving in at the same speed it propagates. Maybe we are not at rest in our own frame inside earths gravity well with respect to space. ...While reading this, I asked myself the following:How is that, as spacetime expands, the matter in our universe is dragged outward along with it (or is this my misconception?) and that the invisible part is receding from us at greater than the speed of light (Vgalaxies + Vspacetime), while with a black hole spacetime is dragged in, and acceleration toward the black hole is solely due to gravity. Vmax = c, not c + speed of dragged spacetime. Why is that? Due to time dilation / length compression? Is this a proprietary property of a black hole, being able to stretch spacetime into itself without dragging in matter at V > c ?Can anyone clear this up for me with a good explanation?-PS maybe a better question is: Why can expanding spacetime without gravity well expell matter from "us"at V>c while a blackhole with it's monster gravity can suck in spacetime so brutally but fail to suck in matter at V>c ?This article kind of helped me with your question. Here is a quote, "how we could possibly see a galaxy that is moving away from us faster than the speed of light! The answer is that the motion of the galaxy now has no effect whatsoever on the light that it emitted billions of years ago. The light doesn't care what the galaxy is doing; it just cares about the stretching of space between its current location and us. So we can easily imagine a situation where the galaxy was not moving faster than the speed of light at the moment the light was emitted; therefore, the light was able to "outrun" the expansion of space and move towards us, "http://curious.astro.cornell.edu/about-us/104-the-universe/cosmology-and-the-big-bang/expansion-of-the-universe/616-is-the-universe-expanding-faster-than-the-speed-of-light-intermediateSo in a sense I think that when the light was emitted the velocity of the space it passed through never went above the speed of light so it made it to us but was still stretched due to the expansion (red shifted). This seems to imply that if the space light passes through does go above the speed of light then the light doesn't reach us and may be similar to a black hole but with an event horizon that surrounds us. In a sense everything freezes at the event horizon and time stops so it doesn't go above light speed but then maybe the universe does that to hide anything that does go above c. It is an interesting subject in that it seems to suggest space is moving and dragging us with it.
Quote from: dustinthewind on 06/11/2015 01:45 amQuote from: Rodal on 06/11/2015 01:13 amDisturbing to se the EM Drive's strange preference of one direction vs. another (reminds me of the issue with NASA turning it around by 180 degrees). I have been wondering if a preferred frame means that there is a specific velocity at which it appears one should be at rest. I would suspect that this might be so. Far away from a gravity well, maybe we can assume space is stationary, and light speed is about the same in any direction from a 3rd observer displaced from all gravity. Inside a gravity well however, lets assume space time is moving into the gravity well. With a black hole, at the event horizon lets say, space is moving in at the speed of light. At that point light cant escape because space is moving in at the same speed it propagates. Maybe we are not at rest in our own frame inside earths gravity well with respect to space. ...While reading this, I asked myself the following:How is that, as spacetime expands, the matter in our universe is dragged outward along with it (or is this my misconception?) and that the invisible part is receding from us at greater than the speed of light (Vgalaxies + Vspacetime), while with a black hole spacetime is dragged in, and acceleration toward the black hole is solely due to gravity. Vmax = c, not c + speed of dragged spacetime. Why is that? Due to time dilation / length compression? Is this a proprietary property of a black hole, being able to stretch spacetime into itself without dragging in matter at V > c ?Can anyone clear this up for me with a good explanation?-PS maybe a better question is: Why can expanding spacetime without gravity well expell matter from "us"at V>c while a blackhole with it's monster gravity can suck in spacetime so brutally but fail to suck in matter at V>c ?
Quote from: Rodal on 06/11/2015 01:13 amDisturbing to se the EM Drive's strange preference of one direction vs. another (reminds me of the issue with NASA turning it around by 180 degrees). I have been wondering if a preferred frame means that there is a specific velocity at which it appears one should be at rest. I would suspect that this might be so. Far away from a gravity well, maybe we can assume space is stationary, and light speed is about the same in any direction from a 3rd observer displaced from all gravity. Inside a gravity well however, lets assume space time is moving into the gravity well. With a black hole, at the event horizon lets say, space is moving in at the speed of light. At that point light cant escape because space is moving in at the same speed it propagates. Maybe we are not at rest in our own frame inside earths gravity well with respect to space. ...
Disturbing to se the EM Drive's strange preference of one direction vs. another (reminds me of the issue with NASA turning it around by 180 degrees).
The guys from hackaday.io posted an update with some raw data graphs: https://hackaday.io/project/5596-em-drive/log/19330-original-recordingsI am greatly enjoying the discussion here on NSF, its a great learning experience and should be used in lessons at schools and universities as an example of the scientific method (which many scientists are forgetting nowadays).
I'm trying to deduce the thrust from the Baby Emdrive data, and failing.Let q represent dw/dt or the angular acceleration (always < 0), whereq0 is the acceleration with the drive off = -29.408q+ is the acceleration with the drive prograde (impeding decay) = -24.987q- is the acceleration with the drive retrograde (assisting decay) = -35.007where the numbers have been read off from the interpolated graphical slopes.Let b = the constant frictional force acting against the motion (Newtons)Let F = the drive force (Newtons)Let a = I/R, so that a*q is also in Newtons (torque = moment of inertia * dw/dt)Then we have 3 equations in 3 unknowns:1. a q0 = -b2. a q+ = -b + F3. a q- = -b - FFor consistency we are forced to have 2 q0 = q+ + q- and from the interpolated graphical slopes, this is quite nicely the case (58.82 vs. 59.99).However, we cannot solve for F independently of a or b.Bummer. Or am I being stupid?
Well, someone might built a one meter frustum and connect it to a couple megawatts (continuous power) klystron at 300 Mhz but no one will spend such amount of money without clear evidence.
Quote from: Paul Novy on 06/11/2015 09:31 amWell, someone might built a one meter frustum and connect it to a couple megawatts (continuous power) klystron at 300 Mhz but no one will spend such amount of money without clear evidence.Chicken and egg thing. Well, this is what I advocate too. It should be built by some lab. They must accept the risk that it will prove nothing, or it may be a breakthrough. It is expensive for a Diy-er, but it's a peanut for the Defense industry...
Quote from: Vix on 06/11/2015 11:27 amQuote from: Paul Novy on 06/11/2015 09:31 amWell, someone might built a one meter frustum and connect it to a couple megawatts (continuous power) klystron at 300 Mhz but no one will spend such amount of money without clear evidence.Chicken and egg thing. Well, this is what I advocate too. It should be built by some lab. They must accept the risk that it will prove nothing, or it may be a breakthrough. It is expensive for a Diy-er, but it's a peanut for the Defense industry...(...)Before research and development of the EMdrive goes any further it will have to build up some credibility first. None of the established institutes wants to participate in what could turn out the biggest hoax of this decade...
Flight Thruster build update:From the best photo of the Flight Thruster I could find and allowing for 2mm thick walls, to add thermal mass and reduce the rate of thermal expansion, the following internal Flight Thruster dimensions were obtained:Length: 138.6mmSmall diameter: 125.7mmBig diameter: 231.4mmApplying those to my spreadsheet generated:Df: 0.638Frequency: 3.85GHzMode: TE013I then asked Roger Shawyer did I get close? His reply:Df: 0.635Frequency: 3.9003GHzMode: TE013I'm VERY happy with that as my Rf gen can easily go to that frequency. Time now to finalise drawings and get some copper sheet laser cut.Roger also mentioned it is best to give the internal frustum surfaces a nice bright shinny polish. No need for Silver or Gold overcoats.
Quote from: TheTraveller on 05/28/2015 04:43 pmFlight Thruster build update:From the best photo of the Flight Thruster I could find and allowing for 2mm thick walls, to add thermal mass and reduce the rate of thermal expansion, the following internal Flight Thruster dimensions were obtained:Length: 138.6mmSmall diameter: 125.7mmBig diameter: 231.4mmApplying those to my spreadsheet generated:Df: 0.638Frequency: 3.85GHzMode: TE013I then asked Roger Shawyer did I get close? His reply:Df: 0.635Frequency: 3.9003GHzMode: TE013I'm VERY happy with that as my Rf gen can easily go to that frequency. Time now to finalise drawings and get some copper sheet laser cut.Roger also mentioned it is best to give the internal frustum surfaces a nice bright shinny polish. No need for Silver or Gold overcoats.I was reviewing the data for the Flight Thruster to include in the EM Drive wiki, and I noticed the following differences: Length(m) BigDiameter(m)TheTraveller: 0.1386 0.2314Shawyer's paper: 0.164 0.265Difference: 18% 15%Where Shawyer's paper reference means this paper:page 9 of IAC- 08 – C4.4.7, MICROWAVE PROPULSION – PROGRESS IN THE EMDRIVE PROGRAMME, Roger Shawyer (http://www.emdrive.com/IAC-08-C4-4-7.pdf)QUESTION: What is the reason for the 18% difference ? (If this was previously discussed in other posts, I forgot)and how do we know which one is correct?If the difference is due to using external dimensions (Shawyer's paper) or internal dimensions (TheTraveller) then this would imply that the wall thicknesses (assuming given by the difference in radii) are:lateral walls=((265-231.4)/2) mm= 16.8 mm (0.661 inches)which are much, much thicker than what NASA Eagleworks used
Quote from: deltaMass on 06/10/2015 03:40 am(...) the water float idea is probably the best of all for seeing thrust directly - and its dynamics. (...)1. Place the device on the old fashioned Foucault test bench.2. See the air currents around.3. ??4. PROFIT
History repeats itself. Which reminds me of Leo Szilard in the 1930'es. Skeptics need a proof first. As it looks now, it could easily happen that the Chinese will provide it...
Quote from: Rodal on 06/11/2015 02:53 pm...I was reviewing the data for the Flight Thruster to include in the EM Drive wiki, and I noticed the following differences: Length(m) BigDiameter(m)TheTraveller: 0.1386 0.2314Shawyer's paper: 0.164 0.265Difference: 18% 15%Where Shawyer's paper reference means this paper:page 9 of IAC- 08 – C4.4.7, MICROWAVE PROPULSION – PROGRESS IN THE EMDRIVE PROGRAMME, Roger Shawyer (http://www.emdrive.com/IAC-08-C4-4-7.pdf)QUESTION: What is the reason for the 18% difference ? (If this was previously discussed in other posts, I forgot)and how do we know which one is correct?If the difference is due to using external dimensions (Shawyer's paper) or internal dimensions (TheTraveller) then this would imply that the wall thicknesses (assuming given by the difference in radii) are:lateral walls=((265-231.4)/2) mm= 16.8 mm (0.661 inches)which are much, much thicker than what NASA Eagleworks used Any dimensional data Shawyer provides is always external overall dimensions. Then you use photos to estimate internal dimensions. I used 2mm thick walls for the Flight Thruster to give more thermal mass & less dimensional movement during thrust pulses.
...I was reviewing the data for the Flight Thruster to include in the EM Drive wiki, and I noticed the following differences: Length(m) BigDiameter(m)TheTraveller: 0.1386 0.2314Shawyer's paper: 0.164 0.265Difference: 18% 15%Where Shawyer's paper reference means this paper:page 9 of IAC- 08 – C4.4.7, MICROWAVE PROPULSION – PROGRESS IN THE EMDRIVE PROGRAMME, Roger Shawyer (http://www.emdrive.com/IAC-08-C4-4-7.pdf)QUESTION: What is the reason for the 18% difference ? (If this was previously discussed in other posts, I forgot)and how do we know which one is correct?If the difference is due to using external dimensions (Shawyer's paper) or internal dimensions (TheTraveller) then this would imply that the wall thicknesses (assuming given by the difference in radii) are:lateral walls=((265-231.4)/2) mm= 16.8 mm (0.661 inches)which are much, much thicker than what NASA Eagleworks used
Quote from: TheTraveller on 06/11/2015 03:06 pmQuote from: Rodal on 06/11/2015 02:53 pm...I was reviewing the data for the Flight Thruster to include in the EM Drive wiki, and I noticed the following differences: Length(m) BigDiameter(m)TheTraveller: 0.1386 0.2314Shawyer's paper: 0.164 0.265Difference: 18% 15%Where Shawyer's paper reference means this paper:page 9 of IAC- 08 – C4.4.7, MICROWAVE PROPULSION – PROGRESS IN THE EMDRIVE PROGRAMME, Roger Shawyer (http://www.emdrive.com/IAC-08-C4-4-7.pdf)QUESTION: What is the reason for the 18% difference ? (If this was previously discussed in other posts, I forgot)and how do we know which one is correct?If the difference is due to using external dimensions (Shawyer's paper) or internal dimensions (TheTraveller) then this would imply that the wall thicknesses (assuming given by the difference in radii) are:lateral walls=((265-231.4)/2) mm= 16.8 mm (0.661 inches)which are much, much thicker than what NASA Eagleworks used Any dimensional data Shawyer provides is always external overall dimensions. Then you use photos to estimate internal dimensions. I used 2mm thick walls for the Flight Thruster to give more thermal mass & less dimensional movement during thrust pulses.OK, I understand you are saying that the dimensions given by Shawyer are external dimensions, but I don't understand the difference between the dimensions and your saying that you used 2mm walls.Please take a gander at my message again, I calculate the walls to be 16.8mm based on the discrepancy between the data, while you give 2 mm. Those are off by a huge factor of 8. (2*8= 16)Any further comments as to why there is this discrepancy?
...Maybe LOOK at the photos. Notice the really wide & thick flanges on the ends. Need to subtrace 2x the flange width, then 2mm for wall thickness from the 265mm overall width to get big end internal diameters.