SOME GRAPHIC STUDIES OF THE ACTIVE GYRO STABILIZER. 187 



plant will be less than one-third, and the space required less than one-tenth of 

 that required by anti-rolling tanks as practically located and applied to vessels for 

 equal roll quenching power. 



Plate 115 shows the active gyro stabilizer to the left and the controller to the 

 right with the precession motor between. This plant is designed to deliver to a 

 model of the 32,000-ton battleship, having a ratio of 30 to i and a period of 2.97 sec- 

 onds, a control impulse of from 4 degrees to 5 degrees per half period or up to 10 

 degrees per period. Such a model really amounts to a boat of quite large propor- 

 tions, whereas the comparatively small size of the stabilizing plant itself, even when 

 running at extremely low stresses, is brought out by the fact that the wheels are 

 only 5 inches (13 cm.) in diameter by 2 inches (5 cm.) face. They run at only 

 about 2,000 pounds per square inch (146 kg. per square centimeter) maximum 

 fiber stress for the wheel. 



Plate 116 shows the back view of the cycloid-pendulum and the stabilizing plant. 

 The pendulum load approaches one-third of a ton, having the various characteris- 

 tics described in the paper. This view also shows some of the elevated weights. 



Plate 117 shows the forward view of the cycloid-pendulum and also the wave 

 maker consisting of the platform upon which reciprocates the solid iron roller. The 

 end of the long pitman is also shown in this plate. These impressed forces act al- 

 most perfectly as a pure sine wave function. 



Plate 118 shows the operating end of the long pitman of the wave maker and 

 also the double recording device, by means of which most of the records were taken, 

 giving the exact relative timing of both the impressed forces and the resulting be- 

 havior of the "ship" under conditions of various friction factors, various stabilizing 

 moments and a wide range of phase relations. 



DISCUSSION. 



The Chairman : — 'Mr. Sperry's paper is now before you for discussion, gentlemen. I 

 do not know whether it is with you, as it is with me, but I think there are probably few 

 people who understand all the mysteries of this system, so most of us do not feel competent 

 to discuss it; but, undoubtedly, there are some gentlemen who have gone into it carefully 

 and do understand it, and they may be able to discuss it, to some extent. 



Mr. Sperry: — Possibly there may be some questions; I will be glad to tell you any- 

 thing we have learned. 



The Chairman : — Of course the object of discussion is to throw light on the ques- 

 tion, and if there is any gentleman who would like to ask questions that will shed light on 

 the matter, we would be glad to hear them. 



