That's true only until we discover that it's not. Remember, According to the standards at the time, man would never fly, never go faster than the speed of sound, etc. I'm not talking about perpetual motion but there are just so many things we think we know only to find out later that what we thought we knew was only the tip of the iceberg.
Robert At 06:09 PM 8/2/2014, you wrote:
There's essentially no chance that a thruster can work where you turn it on, feeding only electricity through it, and with nothing leaving it; where you switch it off, and you're now moving faster. This is what the emdrive is claimed to do.If you could do that, we're in perpetual motion territory; because it violates both conservation of momentum, and (more subtly) it can be shown to violate conservation of energy.The emdrive paper tried to fix that by using the kinetic energy equation in one frame of reference, but you can show that energy is violated in every other frame of reference except the one he did the calculation in. So he's done something wrong. You can fix it, if you introduce an efficiency variable, and set the variable to zero.On 2 August 2014 23:44, Willow Schlanger <<mailto:wschlanger@xxxxxxxxx>wschlanger@xxxxxxxxx> wrote:I just bought the AIAA paper (it's a 21 page PDF) from this location: <http://arc.aiaa.org/doi/abs/10.2514/6.2014-4029>http://arc.aiaa.org/doi/abs/10.2514/6.2014-4029 I also discovered I have an old paper on the EmDrive from "Satellite Propulsion Research Ltd." The filename is "theory paper V9.3.doc" and I received it September 16, 2006 from (if I remember correctly) Roger Shawyer. Here is the first sentence from the Abstract: "A new principle of electric propulsion for spacecraft is introduced, using microwave technology to achieve direct conversion of d.c. power to thrust without the need for propellant." It's been a while since I've read that paper (and I'm surprised I was able to find a copy of it saved from all those years ago), but I don't think it mentioned anything quantum related. I'm taking a quick look; I think he attempted to use only special relativity and non-quantum physics to describe the effect. I'm not sure I'll be able to figure out what any of this means, but I'll try to do some reading and post my thoughts here, if I can decipher what they're all talking about. The AIAA paper was $25.00, and the old "theory paper" mentioned above was sent to me back in 2006 for free (but both documents are copyrighted so I can't share them). Willow SchlangerOn Sat, Aug 2, 2014 at 1:26 PM, Satadru Pramanik <<mailto:satadru@xxxxxxxxx>satadru@xxxxxxxxx> wrote: There's some discussion of the merits of this paper on reddit by this user here:<http://www.reddit.com/user/dalovindj>http://www.reddit.com/user/dalovindjHe says that the null article wasn't a control, but used to test under which conditions the effect occurred:"The null configuration (not the RF load - not the control but the central subject of a test) was one of two test articles. There are two competing theories as to how the phenomenon works. Fetta believes that it works based on asymmetry in the design, while White believes it works by pushing against the quantum vacuum.They tested an asymetric and a symetric design. The symmetric design (neither were "broken") is what they refer to as the null. It was meant to test a prediction of Fetta's theory on how the device produces thrust. He believes that the force is produced by an imbalance of the lorentz force caused by the asymmetric chamber. This test seems to indicate that Fetta's theory is incorrect (or at the very least innacurate). Dr. White's theory on how thrust is produced (pushing against the quantum vacuum), however, predicted that both test articles should produce thrust, which they did. It would seem an endorsement of White's theory over Fetta's."This is stated in the paper as such:Prior to testing, Cannae theorized that the asymmetric engraved slots would result in a force imbalance (thrust). As a result, a second (control) test article was fabricated without the internal slotting (a.k.a. the null test article).Let me know if anybody wants a copy of the paper. Seriously discussing the merits of the physics in this paper is currently above my pay grade.On Sat, Aug 2, 2014 at 11:15 AM, David Weinshenker <<mailto:daze39@xxxxxxxxxxxxx>daze39@xxxxxxxxxxxxx> wrote: William Blair (Redacted sender <mailto:wbblair3@xxxxxxxxx>wbblair3@xxxxxxxxx for DMARC) wrote: > How could they then be certain that air movement caused by the differential heating > of the air within the RF cavity hadn't caused the measured micro-thrust? I must be > missing something because this seems to be too obvious of a potential flaw in the test.Well, the abstract (is the full text available anywhere?) did mention a comparison run they did with an "RF load" replacing the test device, which seems to be intended to control for effects such as you suggest. (If the test device wasn't designed and baked out for operation in vacuum, escaping air from crevices, and outgassing of surfaces, could conceivably create spurious forces of their own if the chamber waspumped down to vacuum.) -dave w -- -Ian Woollard