The "nazi bell" device was supposed to have used large amounts of mercury in order to generate some kind of anti grav effect.
Maybe this is similar technology?
For a heavy object to levitate itself without any visible exhaust (without a special magnet or super conducting platform placed on the ground directly below it), only one known class of particles --neutrinos-- would work.
Wheather they are jets, ramjets, scramjets or pulse detination wave engines, still conventional in that they have all been built and tested on other projects.
SARA is not a "fringe science" group. They carry out contracts for major companies such as Boeing and Lockheed.
Gravity Control by means of Electromagnetic Field through Gas or Plasma at Ultra-Low Pressure
Authors: Fran De Aquino
(Submitted on 8 Jan 2007 (v1), last revised 15 May 2008 (this version, v7))
Abstract: It is shown that the gravity acceleration just above a chamber filled with gas or plasma at ultra-low pressure can be strongly reduced by applying an Extra Low-Frequency (ELF) electromagnetic field across the gas or the plasma. This Gravitational Shielding Effect is related to recent discovery of quantum correlation between gravitational mass and inertial mass. According to the theory samples hung above the gas or the plasma should exhibit a weight decrease when the frequency of the electromagnetic field is decreased or when the intensity of the electromagnetic field is increased. This Gravitational Shielding Effect is unprecedented in the literature and can not be understood in the framework of the General Relativity. From the technical point of view, there are several applications for this discovery; possibly it will change the paradigms of energy generation, transportation and telecommunications