Above is what Woodward hopes to eventually build for propellentless space travel
Here is the kind of device they are testing now
February 2018, James Woodward loaned a good Mach Effect Thruster (accompanied by a specially designed isolation transformer) to Martin Tajmar at TU Dresden, Germany.
But for an unknown reason Tajmar and his team didn’t use the mandatory stepup/isolation transformer: Therefore they operated the device at the wrong frequency, one that could never trigger any thrust signature.
Even worse: as the Dresden team saw nothing conclusive, they increased the voltage for too long and the temperature in the PZT stacks, so they also managed to toast the initially good-working device before returning it to Woodward in California four months later.
Martin Tajmar previously had good results on an 18 year old test device he had received from Woodward.
Woodward team did not know the details of Martin’s lab at Dresden but Woodward knew Tajmar to be a careful experimenter and gifted at getting the latest, best equipment for his lab. Indeed, from his Sevilla conference paper, and the following slides, it is easy to see that their assumptions regarding his lab were justified.
Running without the transformer had led them to run at the wrong frequency. But this aside, those in the popular and semi-popular press latched onto his ambiguous low power results and took them to be grounds for claiming that Mach effects had been falsified. Most of the press attention was lavished on the EM drive for there is no plausible physics to explain its operation should real thrust actually be generated in it. Mach effects were collateral damage. So the question is: what would Martin and students have seen if they had run the device at the correct frequency with a voltage amplitude two to two and a half times the 75 volts they used?
The condition of the demo device when returned was different from that when sent. It had obviously been subjected to a thermal event. The power circuit was falling off the device and its insulation had been singed. The epoxy encapsulation of the PZT stack showed discoloration characteristic of thermal shock. The power wiring was reattached. To my surprise, the device, when tested, worked. Not as well as before sent. But well enough to warrant serious refurbishment.
Piezzoelectrical materials are “ferroelectrical”, for, like ferromagnetic materials, when heated above a “Curie” temperature, they lose their polarization (imprinted on them at fabrication) and cease to show electromechanically inducable behavior. This behavior is critical to the operation of a Mach effect thruster as theory says that the rest mass fluctuations needed are only produced when the “internal” energy of an extended accelerating body changes.
Lead zirconium titanate – so-called “PZT” – is the preferred material for making stacks of (sintered powder and “poled”) crystals designed for operation in the tens of kilohertz range. The stacks must be preloaded, or otherwise they would tear themselves apart when operated at high power. Along with other technical considerations we gloss here, these considerations lead to the construction of devices like that shown in the next slide, the device sent to Dresden for testing.
Over the years two run protocols have been developed by Woodward and his team:
* One involves a sweep of a range of frequencies, used to search for auspicious resonances that amplify the effects that produce thrust. It consists of selecting some frequency and specifying a range of frequencies to be swept. The device is turned on at the center frequency of the sweep for 2 or 3 seconds before the sweep is initiated and again for 2 or 3 seconds at center frequency after the sweep is terminated. This is shown schematically in the next slide.
* The other is operation at constant frequency for sufficient time to allow the balance to settle, about 5 seconds, so that any steady thrust present can manifest itself. In the following runs 8 seconds was chosen, long enough to show steady thrust, but short enough to minimize heating.
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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