Theory of a Mach Effect Thruster
Heidi Fearn · James F. Woodward · Keith Wanser
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In one page
A Mach effect thruster is a stack of ceramic capacitor discs driven hard at its mechanical resonance which, its builders report, pushes without expelling anything. Heidi Fearn presented this paper with James Woodward, Keith Wanser and Adam Zachar at the AIAA Joint Propulsion Conference in Cleveland in July 2014, and it comes in two halves. The experiment: eight lead-zirconium-titanate discs clamped between an aluminium cap and a brass reaction mass, bolted inside a Faraday cage on a torsion balance, driven at 39.3 kilohertz on about 170 watts, giving a clear thrust of just over two micro-newtons that reverses when the cage is turned round — which is how they subtract everything that does not reverse. The theory: Mach’s principle, that a body’s inertia is its gravitational interaction with all the rest of the mass-energy in the universe. Accelerate a body whose internal energy is changing and its mass fluctuates; push while it is heavy, pull while it is light, and the result is steady thrust with no propellant. Fearn then derives Woodward’s mass-fluctuation formula from first principles.
Why it matters hereChapter 8 asks how you get force without throwing mass overboard, and this is that claim in its most instrumented form — a named resonance, a named power, a micro-newton number, and a reversal test that kills the obvious artefacts. Chapter 3 cares about the reason it is supposed to work: inertia as an interaction with the rest of the universe rather than a property a body simply owns. The expanded journal version of this same paper is on the site in full at /library/stm-832f9faf1b.
What it claims
01The Mach effect thruster uses Mach’s principle — the statement that the inertia of a body is the result of the gravitational interaction of that body with the rest of the mass-energy in the universe — to produce a constant acceleration in a device undergoing internal energy changes and mass fluctuations. It requires no propellant, needing only 100 to 200 watts of electric power, and the thrusts at present are on the order of a few micro-newtons.Abstract and Introduction
On the bench now02The operating principle is to push on the object while its fluctuating mass is larger and pull back while it is smaller, which produces a steady linear acceleration detectable in the laboratory. Rapid energy fluctuations are made by applying high alternating voltages to a stack of lead-zirconium-titanate dielectric crystals, whose piezoelectric and electrostrictive properties also force the stack to accelerate. Simply charging and discharging a capacitor will not do it — only the ordinary energy-over-c-squared mass change appears unless the capacitor is also undergoing bulk accelerations.Section A, The MET Experiment
Published and peer-reviewed03The device tested was eight discs of lead-zirconium-titanate, two millimetres thick and nineteen millimetres across, glued together with an embedded accelerometer, clamped between a 4.5 millimetre aluminium cap and a 16 millimetre brass disc and bolted inside a Faraday cage on a sensitive torsion balance. Driven at its 39.3 kilohertz resonance at 185 volts, drawing about 170 watts, it produced a clear thrust of just over two micro-newtons across a fourteen-second pulse.Section A, with Figs. 3 and 4
On the bench now04Spurious signals are removed by running the device facing forward on the balance beam and then reversed, by rotating the Faraday cage through 180 degrees, averaging a dozen runs each way and taking the difference, so that every thrust signal which does not reverse cancels. Thermal expansion is excluded because the six stainless steel bolts hold the stack under compression and the aluminium and brass expand faster than the ceramic, and Dean drive bearing vibration is excluded because it would not reverse and so averages to zero.Section A, run protocol and control tests
On the bench now05Woodward’s mass fluctuation formula can be derived from the linearised Einstein field equations written in Maxwell-like gravito-electromagnetic form, by taking the momentum form of the geodesic equation and allowing the rest mass to vary with time — a route the authors obtained independently three ways. The result adds to the ordinary Poisson equation two mass-fluctuation terms, one in the square of the first time derivative of the mass and one in its second time derivative, together with a term in the square of the acceleration over the square of the speed of light.Section B, New derivation of the Woodward mass change equation, Eq. (27)
Published and peer-reviewed06The linearised theory can produce the mass fluctuation but cannot explain how the accelerating device and the rest of the universe exchange momentum, so the authors turn to the Hoyle-Narlikar theory of gravitation, a fully Machian direct-particle theory in which mass arises only from interaction with all other mass, written in terms of half-retarded and half-advanced mass waves and reducing to Einstein’s field equations in the smooth-fluid limit. Its extra terms reproduce Woodward’s mass fluctuation terms up to numerical factors of three and four. Hawking’s 1965 objection — that advanced waves blueshift to infinite energy in an expanding universe — is answered by admitting negative energy density, which is what present-day cosmology already attributes to dark energy.Section B, Hoyle and Narlikar, and Conclusions
What to watch
The way in
https://doi.org/10.2514/6.2014-3821LICENCE. AIAA 2014-3821 is a conference paper presented in the Nuclear and Future Flight Propulsion technical session of the 50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Propulsion and Energy Forum, Cleveland, Ohio, 28 to 30 July 2014 as printed on the paper’s cover page; the Crossref record dates it 25 July 2014. The American Institute of Aeronautics and Astronautics holds the copyright and the Unpaywall record for this DOI reports the paper as closed, with no open-access location and no licence. An author manuscript of the same paper circulates on the open web, but it carries no Creative Commons statement, so no text is reproduced here and this sheet carries the summary and the claims only, drawn from that manuscript and from the AIAA record. The published Crossref record names three authors, Fearn, Woodward and Wanser; the author manuscript adds a fourth, Adam Zachar of the Space Studies Institute, who built the data-acquisition system and is credited in the acknowledgements. WHERE TO READ IT. The following year the same group published the expanded version under a Creative Commons licence as Theory of a Mach Effect Thruster I, Journal of Modern Physics 6, 1510 to 1525 (2015), and that paper — which supersedes and completes this one — is reproduced in full on this site at /library/stm-832f9faf1b.
How to cite it
Heidi Fearn, James F. Woodward, Keith Wanser (2014) Theory of a Mach Effect Thruster. doi:10.2514/6.2014-3821
Where it sits in the curriculum
Inertial mass reduction and transmedium craftInertia and gravity from the vacuumThe evidence ladder