160 
MOTOR INPUT POWER, W 
80 
0 100 200 300 400 500 
DEPTH, fr 
Figure A17. Motor input power vs depth (prior to bearing cun-in). 
accounting for the 14.7 psi atmospheric pressure and the 5 psi overpressure, represents zero 
internal gas pressure and hence no windage loss. [t follows that the vertical distance from 
the horizontal line EF to the sloping line at any depth represents the windage losses at that 
depth, and the value of the ordinate at line EF represents the other losses. 
Input Power vs Time 
MEASUREMENTS. The input power to the HAW-15 projector decreased 
appreciably during the continuous periods of operation at the 500 ft depth. Figure A18 isa 
graph based on the tabulations of input power. The break between 1540 and 1715 is due to 
a failure of shore power. No tabulations of drive current were made between 1715 and 1830 
because of temporary failure of the drive current monitor. Two measurements of input 
power were made on the morning of 22 May (around 0800). The second measurement is 
considered more reliable than the first because of a number of distractions, such as changing 
recorder tape and calibrations, that were occurring simultaneously. The straight line con- 
necting the data between 1900 of 21 May and 0815 of 22 May covers the period when 
HAW-15 operated unattended. 
It was expected that a further drop in input power would be observed when HAW-15 
was again operated at the surface, where the windage losses are minimum. On 29 May, 
therefore, the HAW-15 was operated at NOSC in the air with 5 psi internal overpressure. The 
initial power input was 93.5 watts, 3 watts Jess than measured in air at the beginning of the 
test at Lake Pend Oreille. After 10 minutes the power dropp: * from 93.5 to 79.4 watts. 
CONCLUSIONS ON INPUT POWER VS TIME. The HAW-15 projector required 
less input power with time during the prolonged tests. The initial rapid drop could be due 
to decreasing friction as the bearings warm up and the lubricating grease becomes less 
viscous. This effect might have been evident again on figure Al8 if power measurements 
38 
Ft err tn i A ER RN EAMES AD PRE RRL ap a RE TTI S SEIT LETTE A AITO I 
