In reply to Craig Haynie's message of Sun, 10 May 2015 18:07:28 -0400: Hi, [snip]
It doesn't cost any energy at all to support a car. The ground does this just fine with no energy expenditure. E = F . d. If d = 0, then E = 0. I'm not sure how this applies to an EM drive (if at all), but perhaps it needs to be taken into consideration? >Hello! > >I was hoping the Vorts could help me with this. Roger Shawyer, at minute >2:56 in this video, claims that the next generation EM Drive could >generation 1 tonne of thrust per kilowatt of power. This means that a 1 >tonne car should be able to hover above the ground for the price of one >kilowatt. However, my calculation shows that to be about 48 times a >theoretical maximum. > >Here is the video where he makes the claim at 2:56. > >http://tinyurl.com/ko5v6h7 > >But here is my calculation for a theoretical maximum, calculated two >different ways: > > - > > A joule is a watt-second > - > > A watt is a joule / second > - > > The power required to hover an object is the same power required to > increase the speed of the object from rest, in a weightless environment, to > 9.8 m/s in one second. We know this because the pull of gravity is 9.8 > meters/second2. > - > > The kinetic energy in an object travelling at 9.8 m/s = 1/2 * m * v2. So > for a car of 1000 kg, the energy = 1000 / 2 * 9.82 = 48,020 joules = 48 > kilowatts to do this in one second. > - > > This power should be 1/2 the power to raise an object of the same mass, > to a height of 9.8 meters in one second, since it would require twice as > much energy to do this. > - > > The formula to determining how much energy it takes to raise something > to height = E = m * g (gravitational constant) * h = 1000 * 9.8 * 9.8 = > 96,040 watts-seconds = 96 kilowatts to do this in one second. So it agrees > with the previous result. > >So, I don't understand how any device could hover an object with the mass >of a tonne for less than a theoretical 48 kilowatts. Any thoughts on this >would be appreciated. > >Craig Haynie ( Manchester, NH) Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
