The Woodward Effect (W-E), the supposition that energy-storing ions experience a transient mass fluctuation near their rest mass when accelerated, has been tentatively verified using linear electrical thrusters based on the Heaviside-Lorentz force transformation. This type of electromagnetic field thruster, or Mach-Lorentz Thruster (MLT), purports to create a transient mass differential that is expressed in a working medium to produce a net thrust in the dielectric material contained in several capacitors. These mass differentials are hypothesized to result from gravity/inertia-based Wheeler-Feynman radiation reactions with the rest of the mass in the universe (per Mach's Principle) in order to conserve momentum. Thus if a net unidirectional force is produced in such a device, then mass fluctuations in the working media should be present. A net unidirectional and reversible force on the order of +/- 3.14 milli-Newton or 0.069% of the suspended test article mass was recorded by us in our first high frequency 2.2 MHz test article. The authors also developed a W-E model that integrates the various engineering parameters affecting the design, construction, and performance of W-E based MLTs for the next generation of systems. When Woodward's (2004a, 2004b, 2005) and our test results were compared with the model's predictions, the test results exceeded predictions by one to two orders of magnitude. Efforts are underway to understand the discrepancies and update the model. The test results imply that these devices, when fully developed, could be competitive with ion engines intended for use on satellite station keeping and/or orbital transfers.