Figure 8. Optical RPM Sensor Mounting Bracket
It there is any tape remaining from previous balance
routines, this must be completely removed to ensure a
clear and accurate tachometer signal to the DAU.
e. Place a single, 3-inch strip of reflective tape on the inside of one of the tail rotor blades at the approximate
location as the beam of the optical interrupter, see figure 9. This becomes the target (TGT) blade.