Most skeptics to Biefeld-Brown Effect research would suggest that the best way to determine if this effect is Ion-Wind or a true field-effect propulsion would be quite simply to test it in a complete vacuum. However, for the last several years, the idea of verifying the effect through vacuum-chamber testing has led to inconclusive results, and remained a touchy subject in Biefeld-Brown Experimentation, for a variety of reasons:
1. The required vacuum needs to be about 10E-7 torr, which means a professional pump-down lasting days, usually. Otherwise you simply have a nice neon-lamp. Chambers like this are expensive, and it's tough to maintain seals on the power leads, because odds are you won't be able to put the entire power supply inside the chamber.
2. When a Lifter is operated in a chamber, odds are that it's resting on the floor of the chamber. The skirt of the Lifter often creates a mirror charge causing the Lifter to stick to the bottom of the chamber. Not having charge transfer to reduce the capacitance on the skirt makes the mirror charging more profound, which is basically like superglue holding the Lifter down.
Contrary to NASA's wonderful 1986 tests, the mirror charge dissipates with the square of the distance, giving it an effective range of 6 inches at most. I read an older test report claiming that a Lifter rose in a vacuum due to mirror charges on the 12-foot tall ceiling.
3. Several experiments HAVE been conducted in a vacuum. They all show different results, making them all inconclusive. The Army saw *some* thrust. Jonathan Campbell at NASA saw none. Hector Serrano & Gravitec (Purdue spinoff) saw significant thrust in 2000.
4. It's entirely possible that this is a hybrid effect: if the Biefeld-Brown Effect changes mass, perhaps the entirety of the thrust comes from Ion-Wind, but it acts more efficiently because the mass of the device has been reduced, or the mass of the air has been increased. Thus, perhaps simply charging an object changes its gravitational / inertial properties (actually, this is true: reference the Nordstrom Metric and it's relationship to charge-potential effects on the gravitational constant).
5. Vacuum chamber tests will not explain the obvious anomaly of why a Lifter inside a sealed enclosure will quit spinning when power is applied (and the direction of thrust is up or down, meaning that it's not acting for or against rotational spin). Saviour did an excellent test of this that I have video of, and it clearly violates conservation of angular momentum. Not a sorta-kinda thing: it's obvious. 20 rpm to zero in about 2 seconds, with about 50 watts of HV inside a sealed, rotating container.
6. Of course, the agendas of the test groups also come into play, as well as minor experimental variables that might change things. Do the support-struts conduct? If they change temperature during pumpdown, the salts in balsa or dried-sweat on plastics may become conductive, meaning that charge dissipation will happen regardless of vacuum state.
These are but a few factors underlining the difficulty in validating this effect, and hopefully also providing us with more insight into how complex this research may sometimes be. In the final analysis, the Biefeld-Brown Effect has remained a riddle for the last 40+ years, and will continue to haunt us as an unknown factor for at least several more...
Wired calls him "The Linus Torvalds of Antigravity", but NASA still won't return his calls. Since the birth of American Antigravity in 2002, Tim has been featured on a multitude of television networks, such as Nippon TV and the BBC, as well as extensively covered in print by sources as diverse as Wired Magazine and Jane's Defense Weekly.