Propulsive Effects of a Rotating Mass 



the supports. Thus, when the motor, and therefore the shaft, are in rotation, 

 the collar makes arm oAq rotate around the shaft (4), while the two toothed 

 wheels make it rotate around itself. Therefore, m rotates arovmd OAq that, in 

 turn, rotates around the shaft (4). 



K the weights of all the rotating parts are negligible with respect to the 

 weight (p) of the mass(m) and if the two arms are of equal length (r = r ), then 

 this peculiar fact is proved experimentally: when m reaches point P^ the de- 

 vice behaves as if it were struck by an external force passing through Pj . 

 The force is transmitted to the base (1) by means of the arms, the shaft, and 

 the supports; the base is thus forced to undergo a small displacement on the 

 plane of support in the direction indicated by the arrow. The same thing is not 

 repeated for Pq , symmetrical to p^ , nor for the other points. It follows from 

 this that the device, at each turn of the shaft (4), acquires a small displacement 

 in only one direction. And if the shaft rotates with continuity, the device com- 

 pletes a succession of small jerks, and therefore, a forward motion on the 

 supporting plane. 



Thus, the rotatory motion of the mass corresponds to a forward motion of 

 the device on the supporting plane. 



The experiment also demonstrates that the displacement occurs when the 

 angular speed (w) of the motor shaft (4) is adapted to the dimensions of the de- 

 vice. In fact, if o) is relatively low, the thrust brought about by the mass is not 

 sufficient to overcome the friction resistance from the contact of the base (1) 

 with the supporting plane, and the device remains motionless; if, instead, w is 

 relatively high, the device undergoes strong vibrations, and hops about on the 

 supporting plane in a disorderly fashion. 



The experiment demonstrates, finally, that the propulsive effect of the ro- 

 tating mass can also be obtained without making a complete 360° rotation of the 

 shaft. In fact, if it leaves p^ and is made to rotate the shaft a few degrees, 

 first in one direction and then in the other, each time m passes through Pj we 

 observe the formation of a force that displaces the device on the supporting 

 plane always in the same direction. 



The motion of the mass can be related to the system of orthogonal axes , 

 X, y, and z fixed with the device and having the origin on the point of intersec- 

 tion of the axis of the shaft (4) with the arm along r ; x parallel to the base (1) 

 of the device; y coinciding with the axis of the shaft (4); and z perpendicular 

 to the base. If point Pq belonging to the plane xy is assumed as the origin of 

 the motion, then point P^ is also found on plane xy, but rotated 180° in respect 

 to Pq ; i.e., from Pq it passes to P^, making the shaft (4) rotate 180°. 



The device accomplishes, as has already been said, a propulsive effect for 

 each turn of the shaft (4). If, however, (Fig. 3) we add an arm r' equal to r , 

 we weld to Aq' an arm R' equal to arm R, and we place in Pq ' a mass m' equal 

 to the mass m placed in Pq , we get as a result a device with two masses, 

 which, in one turn of the shaft, generates two propulsive effects. In fact, let 

 us assume point Pq as the origin of the motion. For a rotation of 180°, the 

 mass from Pq passes to Pj and generates a propulsive effect there. In the 



1375 



