b. Turn power switch to the on position.
c. Allow instrument approximately one-half hour to
Setting Range Setting per second) Peak-to-Peak
d. If the transducer or transducers being used are
not connected, they should be connected to meter
circuits as required.
e. Calibrate or match each transducer with the
f. Set the CHANNEL selector switch for connection
with the transducer whose output is desired.
g. If the transducer signal is to be metered without
the use of filters, or other modifying methods, turn
the INPUT NETWORK selector switch to OUT.
Operation and Range Selector Settings
h. If filtering of the signal is desired, turn the
INPUT NETWORK selector switch to 70 for 70 cps
filtering, or to 200 for 200 cps filtering of input signal.
1-50. EVALUATION OF VIBRATION TEST DATA.
i. To measure peak-to-peak displacement, set the
a. Compare the meter indications recorded on the
OPERATION selector switch to one of the D positions.
data sheet (figures 1-9 through 1-12) with the figures
Use the Dx1 position rather than the Dx0.1 position,
given in parentheses for the maximum permissible
engine vibration. If all recorded figures are below
the permissible vibration, the engine as installed,
j. To measure average velocity, set the OPERA-
has passed the vibration test.
TION selector switch to one of the V positions. Use
the Vx1 position rather than the Vx0.1 position,
b. Vibration measured with the 70 cps filter will
include installation, or airframe vibration. If the
recorded meter indication, using the 70 cps filter,
exceeds the maximum permissible engine vibration
k. Adjust the RANGE switch so that meter readings
figures but, using the 200 cps filter, is within permis-
will be above mid-scale. If set to 5, 50, or 500, read
sible figures, the excessive vibration is caused by the
the upper-scale figures. If set to 15, 150, or 1500,
airframe. Corrective action must be taken before the
read the lower group of figures.
aircraft is again tested for vibration, prior to accept-
ance for unrestricted flight.
l. Attach any desired readout equipment whose
characteristics are compatible with the vibration
c. Vibration measured with the 200 cps filter repre-
sents engine vibration only. If the recorded meter
indication exceeds the maximum permissible engine
m. Use a prepared form for the tabulation of all
vibration figures, corrective action must be taken
variables and readings. (See figures 1-9 through 1-12. )
before the engine is again tested for vibration, prior
to acceptance for unrestricted flight.
cations vs. dial settings.
1-51. MAINTENANCE INSTRUCTIONS, VIBRA-
TION METER TYPE 1-117-0105.
1-52. CLEANING AND LUBRICATING. The vibration
meter requires no lubrication or periodic cleaning
ohms or less and velocity sensitivities which
beyond keeping the unit free from dust and foreign
lie between 50 and 150 millivolts per inch per