Impulse Drive – Mach Effect Thruster

The Mach Effect Thruster (MET) is a device which utilizes fluctuations in the rest masses of accelerating objects (capacitor stacks, in which internal energy changes take place) to produce a steady linear thrust. The theory has been given in detail elsewhere and references therein, so here we discuss only an experiment. We show how to obtain thrust using a heavy reaction mass at one end of our capacitor stack and a lighter end cap on the other. Then we show how this thrust can be eliminated by having two heavy masses at either end of the stack with a central mounting bracket. We show the same capacitor stack being used as a thruster and then eliminate the thrust by arranging equal brass masses on either end, so that essentially the capacitor stack is trying to push in both directions at once. This arrangement in theory would only allow for a small oscillation but no net thrust. We find the thrust does indeed disappear in the experiment, as predicted. The device (in thruster mode) could in principle be used for propulsion. Experimental apparatus based on a very sensitive thrust balance is briefly described. The experimental protocol employed to search for expected Mach effects is laid out, and the results of this experimental investigation are described.

Suggestion from Advanced Space Propulsion Workshop in Huntsville Alabama for a null experiment. If we were to place identical brass masses on either side of our active PZT stack, then the mass fluctuations would result in pushes and pulls of equal magnitude and the device should just oscillate a little but show no average thrust. This appeared to be worth testing. It would show that we were able to eliminate any unwanted vibration, noise effects.


We have shown using a Mach Effect Thruster (MET) it is possible to produce a linear thrust with no propellant (1 to 2 micronewtons is the test in this paper). We have utilized the Mach Principle which says in brief, that the inertial mass of a body is determined by its gravitational interaction with the rest of the matter and energy flow in the universe. We sought to prove that we had managed to eliminate all vibration effects from our data and attempted a null experiment. We attached equal size reaction masses to each end of the active PZT stack, this would cause the induced mass fluctuation to push and pull in both directions at once, and the device should not produce a net thrust. In section 3 we have shown that by using equal masses at both ends of our device we can indeed eliminate the net thrust. This is a rather nice way to show that the methods we employ are sufficient to eliminate any systematic “Dean Drive” noise caused by vibration in the system.

In addition we also tried to determine the optimal brass reaction mass to give maximal thrust. We tried several different brass reaction masses, 0.5, 0.625, 0.75, 0.875 and 1.0 inch with masses 64.7g, 80.9g, 96.8g, 112.6g and 128.3g respectively. We found that for the stack N4, the preferred brass reaction mass was 0.625 inch and 80.9g. We have not put all the data here since for a different device one would have to run this kind of test again. But it is clearly something that would be worthwhile to optimize the thrust for a given device.

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