TEST RESULTS 
BENCH TESTS 
Figure 6 is a calibration curve that relates the electrical indicator resistance to 
peak-to-peak piston throw (twice the amplitude of piston motion). 
Shakedown tests proceeded without problems. The V-belt (fig 4) was judged less 
efficient than had been expected and was replaced by a Berg “‘“Min-E” chain with matching 
sprockets. 
TRANSDEC TESTS 
The Transdec tests went without difficulties. Figure 7 gives the measured output 
spectrum with the basic NRAP frequency set at 15 Hz, and with the amplitude set at three - 
values of peak-to-peak piston throw: 0.391 inch, 0.124 inch, and 0.039 inch. The air over- 
pressure in the NRAP was maintained at about 2 psi. The calculated sound pressure levels 
at 1 m for these values (based on a water density of 1.00 g/cm and a sound velocity of 
147 950 cm/s, as reported by LJ Orysiek, manager of the Transdec Facility) are 170.64, 
160.66, and 150.61 dB re | wPa, while the corresponding values given by the Transdec 
instrumentation are 173.3, 162.7, and 152.4 dB re 1 wPa at 1 m. The discrepancies are all 
less than 2.66 dB, which is consistent with the +2 dB stated accuracy (from Orysiek) of the 
Transdec instrumentation, for a measurement taken under the conditions of the test. 
0.3 Wi 
NOTE: MAX EXCURSION (e) 
1S 0.391 INCH P-P ne 
AND 1S OFF SCALE 
FOR INDICATOR 
0.2 
na PROJECTOR THROW VS 
. REMOTE INDICATOR 
READING GOP/TES 4-3-80 
PISTON EXCURSION, inches peak-to-peak 
ole. ae | SASS asta (a 
(¢) 1 2 3 4 5 6 7 8 
INDICATOR RESISTANCE, kQQ. 
Figure 6. Piston throw vs linear transducer resistance. 
