OF GYRO-STABILIZER FOR SHIPS. 45 



From the characteristics of the Widgeon the position selected and the fact 

 that a little gasoline-electric generator installed for the purpose was available for 

 driving the gyro, a wheel of 3 feet diameter by 10 inch face was adopted as the size 

 best suited to the conditions. This wheel, shown in Fig. 2, Plate 30, is run at very 

 low fiber stress, giving a very large factor of safety, the maximum stress being 

 about 12,000 pounds. The current supply being direct current, a direct-current 

 motor was constructed practically as a part of the rotor shaft, as is shown in Fig. 

 3, Plate 30. 



In reviewing this figure it is interesting to note how small a motor is really re- 

 quired to maintain such a wheel as this at a speed of about 2,750 revolutions per 

 minute, this motor having run the wheel repeatedly to 3,500 for over-stressing and 

 test purposes, the motor shown being in excess of the actual spinning require- 

 ments by fully 300 per cent for quickly energizing the mass in getting up to speed. 



At the ends of the shaft are located the main bearings which, though specially 

 made, are the ordinary annular ball type, ample provision being made for taking 

 care of the end thrust. In each end of the casing there are oil wells and a little 

 slowly rotating oil pump which circulates the oil upwardly through the coolers, a 

 strainer seen in Fig. 4, Plate 31, and back over the top of the bearings, thus insur- 

 ing both ample lubrication and cooling of the bearings. The temperature difference 

 between the incoming and outgoing oil is just noticeable when the gyro is doing full 

 duty in heavy weather, this temperature practically equalizing when the gyro is not 

 precessing. 



It is interesting to note that while the radial load on these bearings varies be- 

 tween practically zero and about 6 tons, the power varies only slightly — one ob- 

 servation showed a change of from 35 to 40 amperes only between these two con- 

 ditions. This indicates that the power consumption is due in small degree only to 

 the bearings, be they loaded or otherwise, but largely to windage, which is constant 

 for constant speed, which was maintained in these tests. 



The system of control is practically identical with that which was finally 

 adopted in the last experiments on the Worden, that is, a small auxiliary gyro, 

 shown in Fig. 5, Plate 31, is employed to feel out the incipient rolling of the ship by 

 closing small electrical contacts plainly to be seen, as soon as the ship rolls very 

 slightly one way or the other. These contacts are required to handle only a very few 

 watts, in fact about one-quarter of the energy of an ordinary incandescent lamp, 

 and through a relay switch serve to actuate a small reversing motor which consti- 

 tutes the precession motor shown in Fig. 6, Plate 32. This motor precesses the 

 gyro upon its main supporting gudgeons at the ends of the frame ; it is here that the 

 gyro lays hold upon the ship to control its movements. 



To follow the motion of the precession motor, it is transmitted through a cen- 

 trally located flexible coupling on the periphery of which is seen the solenoid-con- 

 trolled brake, which always goes "on" when the motor is "ofif," and vice versa. 

 The coupling drives a worm engaging a worm gear within the oil-tight housing 

 to the left in the figure (Fig. 5). The steel pinion seen in the foreground at the end 



