15 



2. Both the recorder and bh accelerometers may be expected to furnish 

 trouble-free performance over a period of weeks while installed aboard ship. 

 It is not expected that any appreciable servicing will be required between 

 trips. 



3. The equipment is relatively insensitive to variation in the supply 

 voltage. 



4. The records provide a clear, immediately visible trace and will not 

 be smudged by ordinary handling. 



5- The over-all accuracy of the system is sufficient for the intended 

 applications. It is believed to be accurate within 6 percent over the frequen- 

 cy range from d-c to 1 cycle per second. The recorder itself is accurate 

 within 5 percent over the same frequency range. 



6. The combination of two linear accelerometers to furnish an angular 

 acceleration signal is somewhat inconvenient to install. 



7. The recorder is a versatile unit which may be used as an ordinary 

 recording oscillograph or as a sampling device. It will provide the desired 

 information at a very low cost both in securing and analyzing the data. The 

 records obtained are readily analyzed in terms of the number of times that 

 given magnitudes have occurred. The phase relationship between the several 

 quantities can also be determined with an accuracy depending on the chart 

 speed used. 



8. The time required to make certain types of analyses can be reduced 

 to a minimum by adding a counter device to the recorder which will indicate 

 the number of times that given variations have occurred. 



9. The recorder in its present form has been used to record linear and 

 angular accelerations as well as angular displacements. In addition, it may 

 be used to record any quantity that is impressed on it provided a properly 

 matched input signal is furnished. 



RECOMMENDATIONS 



1 . An automatic date-stamping device should be incorporated in the 

 recorder. 



2. An angular accelerometer should be developed. 



3. Small stable elements should be made available for these recorders. 



4. Consideration should be given to the addition of channels to the 

 present 5 _ channel recorder. 



