The Todeschini/Di Bella Device Part III

Maybe an inertial propulsion?

Early on in the paper On Propulsive Effects of a Rotating Mass, Prof. Di Bella discusses a development of his device which is essentially that shown below. I have also drawn the locus of one of its two out-of-balance masses, from the equations given in Di Bella's paper. 

The Todeschini device, very similar to Di Bella's second device

Mass locus of Di Bella's second device

As far as I know, this device was first invented by Professor Marco Todeschini in 1933, see http://www.circolotodeschini.com.

As can be seen, the relatively minor design change from a single mass to a pair of offset masses, causes these masses to move along loci that are very different from the original. Provided that the design proportions are correct, each mass now has what Di Bella calls a "checkpoint", i.e. a sharp discontinuity in its motion. At this point, which is the only such point in its operating cycle, he says "...the device behaves as if it were struck by an external force..."

Tests

Di Bella and his team subjected various versions of this developed device to extensive testing. These ranged from large versions that could move an automobile sideways, or propel a boat, to smaller versions that were investigated under extremely low friction conditions, e.g. mounted on dry ice sliding across a horizontal smooth slate surface, or on a balanced arm on a very low friction point-pivot, in a 98.4% vacuum.

In these tests, the device behaved just as well in the vacuum as it did in air, whereas a small motor-driven propeller that worked well in air on the same test rig failed to work at all in the vacuum. In the dry ice/slate tests, a running device that was pushed out against its desired direction of movement would slow down, stop and return backwards.

Discussion

In discussing his results, Di Bella wrestles with the obvious problem:—

"...It seems very difficult to give an explanation for this forward motion. On the one hand, we have definite proof that the device advances, even in the presence of an extremely small amount of friction; on the other, we have the theorem of the motion of the center of gravity, which excludes the possibility of the device advancing, unless there is a friction resistance."

Limits to Newton's laws?

Although the large versions of this device were no doubt interacting with their surroundings, it's hard to see how that could entirely explain the performance of the smaller, extremely low-friction versions. These at least raise the possibility that William O. Davis, a former Director of the US Air Force Office of Scientific Research, was right in suspecting that Newton's second law of motion might not deal properly with cases where higher derivatives of displacement than just velocity (dx/dt) or acceleration (d²x/dt²) are involved. Shock loads, as would occur at the "checkpoint", have many such higher derivatives.

(Reference: "The bigger they are, the harder they fall," Prof. Eric Laithwaite, Electrical Review, 14 February 1975, citing Davis, W.O. "The fourth Law of Motion," Analog Science Fact and Fiction, August 1962 (British Edition), pp. 96-107).

What I should have built

With hindsight, it's easy to see that, rather than the model discussed in my last blog post, with its "smooth" mass locus, I should have built a version of this device with the "checkpoint" in its locus. I may yet do that in future, but currently I have other things higher on my priority-list. 

3D drawing of Di Bella's second device

I did prepare this somewhat schematic 3D drawing, which would be easy enough to turn into a 3D computer model for dynamic analysis. But if it really does depend on non-Newtonian physics, then any model built with currently available modelling software would not be valid.