Paul March is one of the NASA researchers who did the work on the EMdrive, Q drive and Woodward Mach effect propulsion. Paul has some comments about how they did not make a simple thermal error in discussion at Talk Polywell.
Most of the observed forces in the Eagleworks Lab frustum devices were prompt with the same rise and fall times as our electrostatically derived calibration forces and therefore are not thermal in origins. That’s not to say we didn’t see thermal effects, especially with input RF power levels greater than ~35W, but the thermal effects with these large copper plus dielectric test articles, (2.5 to 5.0kg), always take tens of seconds to develop and are easily distinguished from the prompt E and M or more interesting force inputs since they always exhibit exponential rise and fall times.
BTW, the copper frustum’s temperature never rose more than 1.0 degree F. when using the above average power levels and test articles.
Previous coverage of the NASA Cannae drive and EMdrive tests
The 21 page Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum paper is online at Libertarian News.
Abstract – Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum
This paper describes the test campaigns designed to investigate and demonstrate viability of using classical magnetoplasmadynamics to obtain a propulsive momentum transfer via the quantum vacuum virtual plasma. This paper will not address the physics of the quantum vacuum plasma thruster (QVPT), but instead will describe the recent test campaign. In addition, it contains a brief description of the supporting radio frequency (RF) field analysis, ssons learned, and potential applications of the technology to space exploration missions. During the first (Cannae) portion of the campaign, approximately 40 micronewtons of thrust were observed in an RF resonant cavity test article excited at approximately 935 megahertz and 28 watts. During the subsequent (tapered cavity) portion of the campaign, approximately 91 micronewtons of thrust were observed in an RF resonant cavity test article excited at approximately 1933 megahertz and 17 watts. Testing was performed on a low-thrust torsion pendulum that is capable of detecting force at a single-digit micronewton level. Test campaign results indicate that the RF resonant cavity thruster design, which is unique as an electric propulsion device, is producing a force that is not attributable to any classical electromagnetic phenomenon and therefore is potentially demonstrating an interaction with the quantum vacuum virtual plasma.
From the Full paper
Talk Polywell had an intersting comment on the full paper
Eagleworks tested one tapered (frustum) cavity, aka Shawyer’s EmDrive; and two Cannae drives which are also asymmetric but different resonant cavities. The Cannae drive is said to work on a purported different principle than the EmDrive, according to its inventor Guido Fetta (a net Lorentz force imbalance of electrons upon top vs bottom wall of the cavity). According to this purported working principle, one Cannae drive had radial slots on its rim as required by Fetta in order to produce net thrust, and the second Cannae drive didn’t have those slits and was intended to be a “null test device”. But the Cannae null test article… also produced net thrust (20 to 40 µN of net thrust depending of the forward or backward direction).
The null device having thrust means that the Cannae drive theory that the slits mattered was not true. However, this is irrelevant as to whether the Cannae drive produces thrust. Another theoretical explanation is needed but the anomalous thrust remains
We’re talking of net thrust because of course the setup was also tested with a null 50 ohm load connected, in order to cancel the effect from the drives and detect any detect any spurious force due to EM coupling with the whole apparatus (which exists, at 9.6 µN) and this “null” spurious force was evidently subtracted from any thrust signal due to the drives then tested on the pendulum.
All tests articles (the EmDrive version, the Cannae drive version, and even the Cannae “null test” version) had a dielectric embedded within. This is a hint for a different theoretical explanation involving EM fields, proper acceleration, mass fluctuation and dielectrics. Maybe Mach effects (due to Mach’s principle), as supposed by Woodward and Fearn within the GR theory, or within a scalar-tensor theory of gravity according to Minotti.
The Cannae drive website from 2011 is still available on the web archive. Guido Fetta’s Q drive work and his expectation to revolutionize space travel are on the site.
Fetta’s experimental results are detailed. Also, numerical work and what he believes are the Principles.
EMDrive thrust does not seem to scale with higher Q with these tests
What space missions are possible with early versions if this is true?
Based on test data and theoretical model development, the expected thrust to power for initial flight applications is expected to be in the 0.4 newton per kilowatt electric (N/kWe) range, which is about seven times higher than the current state of the art Hall thruster in use on orbit today. The following figures show the value proposition for this class of electric propulsion. A conservative 300 kilowatt solar electric propulsion roundtrip human exploration class mission to Mars/Deimos. A 90 metric ton 2 megawatt (MW) nuclear electric propulsion mission to Mars that has considerable reduction in transit times due to having a thrust to mass ratio greater than the gravitational acceleration of the Sun (0.6 milli-g’s at 1 AU). The same spacecraft mass performing a roundtrip mission to the Saturn system spending over a year around two moons of interest, Titan and Enceladus. Even in this last class of mission which requires only a single heavy lift launch vehicle, the mission has less mission duration than is common with a current conjunction-class Mars mission using chemical propulsion systems and which would require multiple heavy lift launch vehicles. 300 kW SEP Roundtrip Mission to Mars Deimos (50 day stay) departing from DRO 300 kW SEP
What are the next research steps ?
The lessons learned with antenna design and location have been factored in and the design of both the drive and sense antenna s have been explicitly optimized to excite the RF thruster at the target frequency and mode (e.g.,the optimal location has been analytically determined). The thrust performance of this next generation tapered test article has been analytically determined to be in the 0.1 newton per kilowatt regime. Vacuum compatible RF amplifiers with power ranges of up to 125 watts will allow testing at vacuum conditions which was not possible using our current RF amplifiers due to the presence of electrolytic capacitors. The tapered thruster has a mechanical design such that it will be able to hold pressure at 14.7 pounds per square inch (psi) inside of the thruster body while the thruster is tested at vacuum to preclude glow discharge within the thruster body while it is being operated at high power. A phase lock loop (PLL) solution has already been implemented and evaluated at the 1 GHz frequency range, and is being tailored to be able to support testing at multiple set points all the way up to 2.5 GHz. The near term objective is to complete a Q -thruster breadboard test article that is capable of being shipped to other locations which possess the ability to measure low thrust for independent verification and validation (IV&V) of the technology. The current plan is to support an IV&V test campaign at the Glenn Research Center (GRC) using their low thrust torsion pendulum followed by a repeat campaign at the Jet Propulsion Laboratory (JPL) using their low thrust torsion pendulum. The Johns Hopkins University Applied Physics Laboratory has also expressed an interest in performing a Cavendish Balance style test with the IV and V shipset
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