The Woodward-Effect is different than the "offcenter rotator" designs that we've seen promoted online as inertial propulsion devices. In principle, the claim is that these devices use a partially-constrained rotation to produce directional kinetic thrust -- similar to throwing a yo-yo and hoping that it carries you with it. In practice, these devices are difficult to build, self-destruct quite often, and none of them seem to reliably violate Newtons 3rd Law of motion (for every reaction, there exists an equal and opposite reaction).

The Woodward-Effect relies on a Piezo-electric transducer that flexes in response to an electrical current. This overview explains the difference between this approach and the traditional "throwing mass" approach, and provides a bit of illumination on how March & Woodward are verifiably generating thrust in the laboratory:

The basic difference between the “hundreds “ of inertia drives that have failed like the Dean Drive, is based on the issue of scale and energy storage.  The scale portion of this issue drives the magnitude of the available accelerations and quite possibly the type of gravity / inertial coupling to the Far Off Active Matter (FOAM) in the universe.  Where as the Dean drive type devices can only generate accelerations on the order of 1,000s of gees of the constituent atoms of their metallic counter weights, the piezoelectrics can produce atomic accelerations that are on the order of BILLONS of gees or higher.  And since we are talking about relative motion between atomic particles as well, we also may have quantum mechanical effects such as quantum entanglements going on that may be an alternate explanation to the older Machian - Wheeler/Feynman radiation reaction forces that are also effectively instantaneous at work as well or instead of.  This is one area that needs more research and more data.

The other major difference between the Dean Drives and the piezoelectrics is that each active ion in the piezoelectric that is producing the Woodward Effect is traversing an electric field potential gradient while being accelerated at the already noted humongous gee loadings.  And Woodward has already found out that without this potential gradient, there are no mass fluctuations generated in the dielectric.  As to the why of this, we believe that it has to do with the issue of changing the piezoelectrics’ overall energy state relative to the FOAM.  It’s the E=mc^2 bit and since the 4pGr0 varies in lock step with the instantaneous potential energy of dielectric, i.e., the E=C*V^2, this has to be the underlying causative agent in generating the mass fluctuations in the piezoelectric dielectrics.  

So now that we have the first and most important thing required to generate the W-E, i.e., the mass fluctuations, what can we do with them?  Without some type of force rectification system in place, these mass fluctuations will time average to zero over one cycle.  So we now have to supply a force rectification signal to the mass with the mass fluctuations to get a unidirectional force from same.  This is the other key difference between the Dean Drives and the piezoelectrics since if memory serves the Dean drives don’t have this capability either or at least I don’t think they do.  This is where the Slepian vxB business comes to bear and it is what we use to convert the interesting but useless mass fluctuations into a unidirectional force that can do work and lift objects like you and me off the ground. 

After a bit of reflection on the issue of whether Dean Drives have a force rectification function, I now have to say that they actually do have one and it’s wrapped up in their asymmetric, counter rotating counter weight arrangement that could provide a pulsed unidirectional force, IF they had the appropriately timed differential mass fluctuations to react on.  But since the Dean Drive’s mass fluctuations are so small in comparison to the piezoelectrics approach, (nano-grams at best in comparison to grams in the piezoelectrics and yes they should generate mass fluctuations in their accelerated masse, due to their metallic ion’s accelerations in a centripetal gee field that acts like the E-field in the piezoelectrics), all they can do in a freely suspended configuration while in a vacuum will be to just sit there and vibrate around their center of gravity. 

Why?  Because with a net force being generated that it is so small that it’s effectively not there, you will have a thrust to weight ratio of 1x10-9 to 1 or smaller, so you would have to wait a long, long time in a gravity free environment to see if anything is really happening.  But when you can push and pull on gram+ mass differentials as seems to be the case in these piezoelectric vxB devices, the thrust to weight ratios can start to be interesting for engineering purposes.  In fact, our very conservative W-E performance spreadsheet indicates that the Vishay/Draloric TOS based door-knob caps could have thrust to weight ratios on the order of 5-to-1 at a minimum and could be as high as 500-to-1 dependent on their operating point and the actual scaling rules that have yet to be nailed down.

What our community needs is enthusiasm and big picture thinking.  I'm hoping to convey the idea that we’ve been there, done that and are well aware of what the big picture could be like if we can actually make the MLTs live up to their apparent potential.  But there is this hugh “IF” sitting in the way to our solar system and star fairing dreams that has to be removed by detail examination of the technical minutia, with iterative theoretical musing, followed by more experimentation and data taking.  That’s what we’ve been doing for seven plus years and we will continue to do so until we prove the effect isn’t what we though it was, or we have the MLTs levitating in a repeatable manner.  I’m hoping for the later, but I’m prepared for the former if that is the true case.  Thus my repeated comments in this group that we can’t let ourselves get too excited most of the times until we see the MLTs move on their own in such an unambiguous way that there can be no doubt to the reality of the effect.  Then we can go shout it to the roof tops!  But only then…

Here's the short version in the difference between the operation of the off center rotators (OFR)s and the W-E MLT’s.  In a nutshell, the mechanical Dean drive like OFRs operate very close to their at rest inertial equilibrium states, which means that they don’t generate mass fluctuations to any notable degree, and what little they do generate aren’t force rectified into a single vector unidirectional force.  Its all about degrees of performance and to date and as you noted, none of these OFR approaches have even come close to generating anything useable force wise. 

The W-E on the other hand presents the user with some fairly straight forward requirements for them to work.  The MLTs have to a.) produce large amplitude mass fluctuations in a material and b.) they have to be able to force rectify these mass fluctuations into a unidirectional force.  Provided mass fluctuation are real, and all the known data to date says they most probably are, there are a number of ways to do each of these tasks and they can be accomplished in any material that can be electrically manipulated at high frequency.  Why electrically?  Because that is the only currently know way to generate mass fluctuations large enough to be useful.  Mechanical OFRs can only run up to several tens of thousands of rpm’s before they blow themselves apart from internal centrifugal forces.  But what’s needed is hundreds of thousands of revolutions per second or higher to even get started into the operating range of interest. 

But there’s a simpler and safer way to do this.  Use electrical dielectrics that can store and discharge energy and accelerate ions at the same time.  That’s why we are using ceramic capacitors for our mass fluctuation material.  Its internal components can be oscillated into the gigahertz range where their ionic acceleration forces can be huge.  They also can simultaneously store and transform potential energy into kinetic energy and back again, which is the other main ingredient to the formation of these mass fluctuations per our current theory. 

But the proof is in the experimental verification and Jim and I have supplied enough data now to be convinced that we are on the right trail to viable MLT’s that can power my noted Mars bound SUV.  But we still need to make a test article that can move under its own power either on a ballistics pendulum or air bearing table before anyone should take us really seriously.  So with that said I’m going back to the lab and see how my 1-to-5 step-up transformer that I wound this afternoon actually works being powered by the signal generator.  See we are back to the technical minutia again, but even then we can still feel the siren call of the stars…