torpedo-borne instrument development , external photographic 

 equipment 9 external instrumentation, underwater trajectory 

 determination, torpedo control studies and operation of the 

 launching facilities. 



Various general schemes for accelerating and launching 

 the torpedo were studied leading to a final decision for the 

 construction of a 300-foot tube for compressed air launching. 

 After a number of improvements in design and construction, 

 the launching tube met general design specifications for 

 entry angle and velocity and put the torpedo into the water 

 with very small amounts of random pitch and yaw. 



For determination of underwater trajectories an acoustic 

 range was designed and installed, utilizing an array of 

 twelve hydrophones with sxiitable amplifiers and a recording 

 oscillograph. Various noise sources within the torpedo were 

 tried, leading finally to a timing device installed in a 

 torpedo hand hold which fired detonating caps at suitable in- 

 tervals. Eventually a mechanical computing device was de- 

 veloped for reduction of oscillograph data to actual trajectories 



In addition to standard motion picture cameras for record- 

 ing the actual water entry from the rear and the side, a 

 rotating disc camera was developed which gave on a single 

 photographic plate the position of the torpedo at each thou- 

 sandth of a second during entry. Special flares were produced 

 for mounting on the torpedo to give sharply defined slit images 

 on a photographic plate which could be accurately measured on 

 a comparator. From these position-time records the velocity 

 and deceleration during entry could be determined with a high 

 legree of accuracy. 



Dummy torpedoes were designed and built to serve as flying 

 laboratories to carry deceleration measuring instruments, 

 structural elements and portions of actual torpedo mechanism. 

 These dummies were built to receive various types of head and 

 tail structures for entry behavior studies, and to permit 

 changes in the dynamic constants of the torpedo . 



Depth Ch arges and Bombs . 



Work was also done on the development of fuzes for fast 

 sinking depth charges. Two special types of firing mech- 

 anisms were developed. 



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