Ok, well if it is used for static thrust only, it is then a coin toss if it would work opposing gravity as static on the surface of the earth experiences 1G of acceleration.
According to the equivalence principle... On Mon, May 11, 2015 at 4:27 PM, Craig Haynie <cchayniepub...@gmail.com> wrote: > Thanks Robin. You're right. He does say that this force of 1 tonne per > kilowatt is for 'static thrust'. > > "I found an answer from the website. He is referring specifically to a > 'static thrust', not used to do work. > > "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. Note however, because the EmDrive obeys the law > of conservation of energy, this thrust/power ratio rapidly decreases if the > EmDrive is used to accelerate the vehicle along the thrust vector. (See > Equation 16 of the theory paper). Whilst the EmDrive can provide lift to > counter gravity, (and is therefore not losing kinetic energy), auxiliary > propulsion is required to provide the kinetic energy to accelerate the > vehicle." > > Craig > > On Mon, May 11, 2015 at 12:19 AM, <mix...@bigpond.com> wrote: > >> In reply to Craig Haynie's message of Sun, 10 May 2015 23:43:04 -0400: >> Hi, >> >" IOW he creates a force, but as long as that force doesn't act over a >> >distance, then it need do no work." >> > >> >I'm the one who suggests that the thrust created by the EM Drive could be >> >used to levitate an object. Shawyer is saying that the EM Drive could >> >create 1 tonne of thrust for 1 kilowatt of power, implying that this >> thrust >> >would be used to accelerate a spacecraft. He's not siting these numbers >> as >> >an example of levitation. So he's implying that the thrust will be used >> to >> >do work, and therefore should not be able to violate a theoretical amount >> >of power needed to do that work. >> >> ...but he isn't stating how much work is done, and hence how much power >> would be >> required. He is just saying that his device even at it's most efficient >> still >> requires that some power be expended to create a force, even though in >> theory no >> power expenditure is required to create a force, see e.g. gravity , or >> even a >> simple spring, which will happily create a constant force, without >> expending any >> energy. IOW the (in)efficiency of the device is what causes the power >> requirement. >> >> What I am trying to say is that the power requirement that he gives, is >> for a >> device doing no work. If it has to do work as well, then the power >> requirement >> will increase accordingly. >> >> Consider for a moment the ultimate form of the drive, which is >> constructed from >> a perfect superconductor with a consequent infinite Q. As the Q increases >> so >> does the force. Or looked at from a different perspective, the power >> requirement >> to obtain a given force decreases as the Q increases. IOW in a perfect >> device, >> the power requirement would approach zero (as long as no additional work >> need be >> done). Which is exactly what a spring does. (And also a current in a >> superconducting loop BTW.) >> >> >> BTW, IIRC (it was some time ago that I read this) he does say somewhere >> that the >> power consumption changes as work is done, and that consequently the >> limits on >> the input power also limit the amount of work that can be done. >> >> Note also that the tests to date, have been done on stationary devices, >> i.e. >> anchored to the work bench, so that they could not move (as I understand >> it), >> and hence did no work. >> >> [snip] >> Regards, >> >> Robin van Spaandonk >> >> http://rvanspaa.freehostia.com/project.html >> >> >
