Quote from: Prober on 01/06/2015 08:25 amGuys, Guys......I stopped reading some time ago.....now we are into the 2nd thread.Not being read or heard. There is absolutely nothing related to spaceflight here.Again, NASA tested what, a 20 watt setup ? That is within power budget of a 3U cubesat. Flight model ? Demonstrate torque, if not directional thrust ?
Guys, Guys......I stopped reading some time ago.....now we are into the 2nd thread.
"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*) 0.01176lengths in meterrfFrequency in 1/second (microwave frequency during test)power in wattsforce in milliNewtonsforce per PowerInput in milliNewtons/kWc= 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 = 10.5Q = 1.1*(10^7)measured force = 8 to 10measured ForcePerPowerInput = 761.9 to 952.4Force/PowerInput of a Photon Rocket =0.003336measured 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 = 18.82Force/PowerInput of a Photon Rocket =0.003337measured ForcePerPowerInput to the one of a photon rocket =5,640(* Shawyer Demo *)rfFrequency=2.45*10^9;cavityLength=0.345;bigDiameter=0.28;smallDiameter= 0.128853power = 421 to 1200Q = 45000(measured force = 102.30 milliNewtons only reported for 421 watts, 243 milliNewtons/kW )measured ForcePerPowerInput = 80 to 243Force/PowerInput of a Photon Rocket =0.003337measured ForcePerPowerInput to the one of a photon rocket =23,980 to 72,830All 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 = 7320measured force = 0.0912measured ForcePerPowerInput = 5.396Force/PowerInput of a Photon Rocket =0.003337measured ForcePerPowerInput to the one of a photon rocket =1,617.2 (* Brady b TM mode*) rfFrequency=1.9367*10^9;power = 16.7Q = 18100measured force = 0.0501measured ForcePerPowerInput = 3.000Force/PowerInput of a Photon Rocket =0.003337measured ForcePerPowerInput to the one of a photon rocket =899.12 (* Brady c TE mode *)rfFrequency = 1.8804*10^9;power = 2.6Q = 22000 measured force = 0.05541measured ForcePerPowerInput = 21.31Force/PowerInput of a Photon Rocket =0.003337measured ForcePerPowerInput to the one of a photon rocket =6,386.7(* Fearn, Zachar, Woodward & Wanser*)rfFrequency = 39,300;power = 170measured force = 0.002measured ForcePerPowerInput = 0.01176Force/PowerInput of a Photon Rocket =0.003337measured ForcePerPowerInput to the one of a photon rocket = 3.526
Quote from: savuporo on 12/31/2014 05:15 pmQuote from: Rodal on 12/30/2014 03:21 pmNone of these experiments have demonstrated a linear acceleration: all of them have measured rotational accelerations. None of the EM Drives have been tested in a vacuum. None of the measured forces are high enough to levitate the drive. Forget about levitation. I havent read much or anything about it, but are the forces even in the same ballpark as existing magnetic torquer rods for cubesats ? If yes, in theory this could assist with attitude control in deep space, at least for desaturation.Anyone ? Anyone ? I mean, actual spaceflight application. Desaturation spends fuel. Can we get a propellantless desaturation device, with main attitude control provided by reaction wheels ? Again, from the claimed experimental setups, are the reported angular momentums even on a scale where they could turn a cubesat - even if it takes a long time to do so ? Its not like torquer rods are fast or anything, but they only work within earths magnetic field.And if it cannot turn a cubesat, the entire thing is no better than Steorn Orbo, is it ?
Quote from: Rodal on 12/30/2014 03:21 pmNone of these experiments have demonstrated a linear acceleration: all of them have measured rotational accelerations. None of the EM Drives have been tested in a vacuum. None of the measured forces are high enough to levitate the drive. Forget about levitation. I havent read much or anything about it, but are the forces even in the same ballpark as existing magnetic torquer rods for cubesats ? If yes, in theory this could assist with attitude control in deep space, at least for desaturation.
None of these experiments have demonstrated a linear acceleration: all of them have measured rotational accelerations. None of the EM Drives have been tested in a vacuum. None of the measured forces are high enough to levitate the drive.
....Ok, let's break it down a bit simpler.How many units of energy are being used to produce how many units of thrust? Newtons as the unit of measure could work.
Throwing around ideas/stuff to think about here:Since the thrust/power ratio of these devices is pretty bad, they are severely limited by the amount of electrical power you can put on orbit.
Quote from: Mulletron on 01/06/2015 10:12 pmThrowing around ideas/stuff to think about here:Since the thrust/power ratio of these devices is pretty bad, they are severely limited by the amount of electrical power you can put on orbit. If it works as Shawyer claims, the superconducting version will be producing far more thrust:http://emdrive.com/faq.html"The second generation engines will be capable of producing a specific thrust of 30kN/kW. Thus for 1 kilowatt (typical of the power in a microwave oven) a static thrust of 3 tonnes can be obtained, which is enough to support a large car. This is clearly adequate for terrestrial transport applications. The static thrust/power ratio is calculated assuming a superconducting EmDrive with a Q of 5 x 109. This Q value is routinely achieved in superconducting cavities."
You meant to write "assuming a superconducting EmDrive with a Q of 5 * 10^9" = 5,000,000,000 (five billion) (rather than Q = 5 x 109 =545).In his IAC 2014 October 2014 presentation Shawyer (in his slide #3 in http://www.emdrive.com/iac2014presentation.pdf ) instead uses a projected Q = 5*(10^7), which is 100 times less than the value assumed by Shawyer for the above 30kN/kW projection.Reviewing actual published data, the maximum Q actually measured for a superconducting EM Drive I have seen reported is for the Canae superconducting drive experiment which gave a Q = 1.1*(10^7), this is 500 times less than the value assumed by Shawyer for the above 30kN/kW projection.Also comparing with actual experimental data, Canae's measured ForcePerPowerInput for the superconducting Canae experiment was only 0.7619 to 0.9524 N/kW, which is 31500 times less than the 30kN/kW projection, therefore besides the decrease in thrust by a factor of 500 due to the lower actual Q, there was another factor of decrease in thrust (by a factor of 63 times) in the actual performance of the experiment (500*63=31500).
Quote from: Rodal on 01/07/2015 12:15 pmYou meant to write "assuming a superconducting EmDrive with a Q of 5 * 10^9" = 5,000,000,000 (five billion) (rather than Q = 5 x 109 =545).In his IAC 2014 October 2014 presentation Shawyer (in his slide #3 in http://www.emdrive.com/iac2014presentation.pdf ) instead uses a projected Q = 5*(10^7), which is 100 times less than the value assumed by Shawyer for the above 30kN/kW projection.Reviewing actual published data, the maximum Q actually measured for a superconducting EM Drive I have seen reported is for the Canae superconducting drive experiment which gave a Q = 1.1*(10^7), this is 500 times less than the value assumed by Shawyer for the above 30kN/kW projection.Also comparing with actual experimental data, Canae's measured ForcePerPowerInput for the superconducting Canae experiment was only 0.7619 to 0.9524 N/kW, which is 31500 times less than the 30kN/kW projection, therefore besides the decrease in thrust by a factor of 500 due to the lower actual Q, there was another factor of decrease in thrust (by a factor of 63 times) in the actual performance of the experiment (500*63=31500).On the plus side, with the right power source, 0.7619 Newtons from a kilowatt of electricity is still, probably, enough thrust to displace rockets for orbital insertion. It's not competing with airplanes, but it is an exciting number.
Quote from: savuporo on 01/06/2015 03:18 pmQuote from: Prober on 01/06/2015 08:25 amGuys, Guys......I stopped reading some time ago.....now we are into the 2nd thread.Not being read or heard. There is absolutely nothing related to spaceflight here.Again, NASA tested what, a 20 watt setup ? That is within power budget of a 3U cubesat. Flight model ? Demonstrate torque, if not directional thrust ?I suggest those of you concerned that NASA is not testing this yet in space make your representations to them.
The future? More power.Two interesting things I found about high power space flight projects at none other than JSC. What is also interesting is that both of these mention Q-thrusters.http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140004802.pdfhttp://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140004416.pdf
it may be that i have an outdated reader but those pdfs fail to load for me. the first gets 2/3s of the way loaded according to the progress bar and then hangs. the second gets 1/4 of the way loaded and then hangs.
Quote from: Stormbringer on 01/08/2015 05:35 amit may be that i have an outdated reader but those pdfs fail to load for me. the first gets 2/3s of the way loaded according to the progress bar and then hangs. the second gets 1/4 of the way loaded and then hangs.NTRS does that a lot with firefox, try chrome or curl/wget
The near term focus of the laboratory work is focused on gathering performance data to support development of a Q-thruster engineering prototype targeting Reaction Control System (RCS) applications with force range of 0.1-1 N with corresponding input power range of 0.3-3 kW. Up first will be testing of a refurbished test article to duplicate historical performance on the high fidelity torsion pendulum (1-4 mN at 10-40 W). The team is maintaining a dialogue with the ISS national labs office for an on orbit DTO.How would Q-thrusters revolutionize human exploration of the outer planets? Making minimal extrapolation of performance, assessments show that delivery of a 50 mT payload to Jovian orbit can be accomplished in 35 days with a 2 MW power source [specific force of thruster (N/kW) is based on potential measured thrust performance in lab, propulsion mass (Q-thrusters) would be additional 20 mT (10 kg/kW), and associate power system would be 20 mT (10 kg/kW)]. Q-thruster performance allows the use of nuclear reactor technology that would not require MHD conversion or other more complicated schemes to accomplish single digit specific mass performance usually required for standard electric propulsion systems to the outer solar system. In 70 days, the same system could reach the orbit of Saturn.
In this report http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110023492.pdf NASA's Dr. White wrote of his continuing "dialogue with the (International Space Station) ISS national labs office for an on orbit DTO (On Orbit Detailed Test Objectives)" of the EM Drive (which he calls "Q-Thruster"):
The "Q-Thruster" in this case appears to be a Woodward/ME device.
Quote from: Rodal on 01/09/2015 12:23 amIn this report http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110023492.pdf NASA's Dr. White wrote of his continuing "dialogue with the (International Space Station) ISS national labs office for an on orbit DTO (On Orbit Detailed Test Objectives)" of the EM Drive (which he calls "Q-Thruster"):The "Q-Thruster" in this case appears to be a Woodward/ME device.
QuoteThe "Q-Thruster" in this case appears to be a Woodward/ME device. Yes. No. Sort of.Despite claimed differing operating principles, the 'Q-Thruster' and Woodward/ME device appear to differ in minor detail, in terms of construction and results. At least that is my (possibly badly flawed) understanding. Heated debates about this in the old thread contributed to its demise. We attempt to keep Woodward/Mach out of this thread, but the equations and thoughts keep heading that way.