G. Harry Stine made a sideline of looking into alleged reactionless drives. He knew how incredibly useful such a thing would be, he really wanted some such thing to be practical, so (typical of the man) he was rigorously skeptical. I went along for the ride on at least one of his visits, to a local guy who was trying to produce thrust mechanically. (As usual, strange things happened when you turned the rpm high enough just before the device flew apart, and as usual, there was no actual thrust involved.)
Harry was actually very kind and polite in letting the guy know it wasn't real. Again, typical of the guy.
(Enough reminiscing, cut to the chase.) I recall Harry explaining that he considered a convincing demo to be: Hang the device on the end of a pendulum in a vacuum, and demonstrate a repeatable constant displacement of the pendulum with power on versus power off.
And it occurs to me to add, twenty years later, since presumably power of some sort is being routed to the device down the pendulum, set things up so the device can be reoriented relative to the pendulum and power feed, to distinguish between pendulum displacement due to the device actually thrusting along some axis, and pendulum displacement due to some power-on mechanical reaction of the power feed.
Henry On 8/2/2014 10:06 PM, Michael Clive wrote:
I bought the paper. I personally don't care about the physics of how it works YET. All I care about is verifying if it works. So I am gonna build one. Here is where yall come in. Let us define what would be a two factor test for this. I want two high accuracy sensors to measure force. I am thinking a diaphragm backed by an ultra high accuracy pizeo pressure transducer, an lvdt to measure displament against the diaphragm and possibly a laser interferometer for measuring distance. Background on me: I work at spacex, used to work at xcor, I live in a giant warehouse with three phase power. I am on first name basis with half the machine shops in los angeles. I build test systems everyday all day. Never done microwaves before but I am a quick learner. What I need from the people on this list is help on design for an ultra sensitive verification system. Then I will start a kickstarter, collect the fifty grand or so from the cloud, and build the thing. I will build it in a portable self contained unit. I will run the first batch of experiments. If there are positive results, I will freely hand it off to the first university that wants to play with it, and so on. If there are negative results, I want to make sure I am the one to put a bullet in this things head. Why do I want to do this? This would change the entire game as far as mars colonization and settlement is concerned. Also, I have many of the required skills to build test and verification equipment, and I am perfectly willing to accept a negative result. If anyone wants to team up, I am based out of los angeles. Here is what I need 1. A primary way to verify operation or non operation of the device, by direct force measument. 2. A secondary indirect system to verify the device. 3. A tertiary analog system to rule out electro magnetic interference. 4. An electrical engineer to help 5. An RF engineer to help. Jb plz 6. Money. Which I will try to kick start cloudfund after I work out a budget for this. Goal is to have a running test bed by January. The paper is pretty clear on expemient setup. If we triple down on verification systems, I think we can nail this to a wall, one way or another. Who's with me? On Aug 2, 2014 5:09 PM, "Ian Woollard" <ian.woollard@xxxxxxxxx <mailto:ian.woollard@xxxxxxxxx>> 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 <wschlanger@xxxxxxxxx <mailto: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 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 Schlanger On Sat, Aug 2, 2014 at 1:26 PM, Satadru Pramanik <satadru@xxxxxxxxx <mailto: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 He 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 <daze39@xxxxxxxxxxxxx <mailto:daze39@xxxxxxxxxxxxx>> wrote: William Blair (Redacted sender wbblair3@xxxxxxxxx <mailto: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 was pumped down to vacuum.) -dave w -- -Ian Woollard