2 upvotes, 1 direct replies (showing 1)
View submission: xkcd: Quantum Vacuum Virtual Plasma
I can't find non-paywalled access to the actual PDF describing the tests (and can't even find the cost without creating an account -- even at a research university's network) [1] only the brief summary[2].
1: http://arc.aiaa.org/doi/abs/10.2514/6.2014-4029
2: http://ntrs.nasa.gov/search.jsp?R=20140006052
Describing it as just "two drives/test articles" is accurate - as well as your description tests of a third test with just an RF load (which in the summary they don't call a drive or a test article). From the summary:
**Several different test configurations were used, including two different test articles as well as a reversal of the test article orientation. In addition, the test article was replaced by an RF load to verify that the force was not being generated by effects not associated with the test article. The two test articles were designed by Cannae LLC of Doylestown, Pennsylvania.**
...
Approximately six days of test integration were required, followed by two days of test operations, during which, technical issues were discovered and resolved. Integration of the two test articles and their supporting equipment was performed in an iterative fashion between the test bench and the vacuum chamber. In other words, the test article was tested on the bench, then moved to the chamber, then moved back as needed to resolve issues. Manual frequency control was required throughout the test. **Thrust was observed on both test articles, even though one of the test articles was designed with the expectation that it would not produce thrust. Specifically, one test article contained internal physical modifications that were designed to produce thrust, while the other did not (with the latter being referred to as the “null” test article).**
There were more than two tests and you describe a third test that wasn't an EmDrive, but an RF load (a simple RF terminator[3]).
3: http://en.wikipedia.org/wiki/Dummy_load#Radio
The fact that their "null" test article found significant thrust (even if smaller in magnitude in the null configuration) is to me a big flag to view their results very skeptically.
Comment by altrocks at 07/08/2014 at 01:56 UTC
1 upvotes, 1 direct replies
It should be viewed skeptically anyway. This is a simple proof of concept test that was only looking at whether or not the devices were producing detectable thrust in various configurations. From the looks of it they were doing everything they could to eliminate outside influences, though there's always room for unknown errors to creep in. This isn't the first time an EM drive has been said to produce detectable thrust, but it's arguable that this is the first time it's coming from a credible source.
If there is an unknown process going on here it's worth investigating. If there is an error causing the readings that's also worth finding as it may indicate problems with the measurement equipment that was unknown before. Either way, this needs to be scaled up and replicated on different equipment by a different team just as the superluminal-neutrino result was.