A demonstration of the Thornson Inertial Engine – an off-center rotator design shown propelling a canoe through a swimming pool during testing by Brandson R. Thornson. The Thornson drive is one of many mechanical-implementations inertial propulsion concepts, and this clip appears to support proponents claims about its workability.
In US Patent #4631971, inventor Brandson R. Thornson published schematics indicating that a force-balanced off-center rotator could produce a net-directional thrust without expelling reaction-mass — a familiar concept investigated by a number of inventors, including Robert Cook with the comment, “In 1990, a 16 foot Grumman canoe and two passengers with a gross weight of 450 pounds demonstrated a low acceleration rate and propulsion of one mph after traveling 75 feet in a swimming pool. The 60 pound Thornson prototype was totally sealed inside a plywood case…”
The scientific basis for inertial propulsion is generally attributed to Mach’s Principle, which states that “the inertia of any system is the result of the interaction of that system and the rest of the universe”. However, recent experimental research by Dr. James Woodward and colleagues has called into question the conventional wisdom that Mach’s Principle can be tested using mechanical systems. In Woodward’s view, the problem becomes an issue of phase-matching that is best solved by a conventional electromagnetic ineraction that serves as the basis for his “Mach-Lorentz Thruster” technology.