The Todeschini/Di Bella Device Part I

Inertial Propulsion

In my blog post of 14 April 2014, I raised the idea of a perpetual motion machine having a number of inertial propulsion devices arrayed around its rim. Of course, these would have to work very efficiently, if the device was to achieve a net energy gain. But even if we set aside the question of efficiency for now, is any inertial propulsion device even possible?

In my next few posts, I'll look at some ideas that could generally be described as inertial propulsion, which I have personally found interesting and worthy of further investigation.

The first Di Bella device

In 1968 Professor Alfio Di Bella of the Institute of Naval Architecture, University of Genoa, published a paper titled "On Propulsive Effects of a Rotating Mass." This paper discussed in detail the extensive testing that was done on some real physical devices constructed by Di Bella and his team. 

(Reference: "On Propulsive Effects of a Rotating Mass", Prof. Alfio Di Bella, Proceedings of the 7th Symposium of Naval Hydrodynamics, Rome, 1968, pp1373 - 1396.)

This paper is one of the less well known, but most interesting and well-researched documents on inertial propulsion. I'll devote this post to Di Bella's original device, and two more to developments of it.

Not an inertial propulsion
 

Fig. 2 from Di Bella's US Patent 3,404,854

Initially, Di Bella's paper discusses this device, from his US Patent 3,404,854. Briefly, the motor 1 turns frame 4, carrying axle 9, counterweight 11 and bevel gear 10, which meshes with the fixed bevel gear 14. This causes the out-of-balance mass m to follow the locus drawn below, known to mathematicians as the "Window of Viviani".

Locus for the mass of Di Bella's original device: the Window of Viviani

Tests

Di Bella says "The device was tested extensively on the ground and on the surface of the water with satisfying results on the whole." Nevertheless, it's apparent (as Di Bella realises and points out) that this device relies entirely on interaction with its surroundings, generally by friction, in order to operate at all.

My own version

For reasons I'll give in my next post, I decided to make a modified version of Di Bella's device. First step: design and make the bevel gears!

Two bevel gears, to my design (but not made by me — bevel gears
require a specialised tooth generating machine, which I don't have)