Robinsons R66 - 18-70 Fan Shaft and Engine Shaft Balancing; 18-71 Preparing Helicopter for Fan Shaft and Engine Shaft Balancing

MAY 2015 Chapter 18 Track and Balance Page 18.33
18-70 Fan Shaft and Engine Shaft Balancing
NOTE
Calibrate track and balance equipment per manufacturer's
recommendation, at least once a year, or if equipment is
dropped, misused, or calibration is suspect.
NOTE
The Chadwick-Helmuth Vibrex system, the TEC ACES system,
the Dynamic Solutions Systems’ MicroVib system, or equivalent
equipment is required to perform dynamic rotor balancing and
in-flight track checks.
18-71 Preparing Helicopter for Fan Shaft and Engine Shaft Balancing
NOTE
Use the following balance procedures in conjunction with
approved equipment manufacturer’s balancing instructions.
1. Remove tailcone cowling per § 53-23. Clean F196-1 fan shaft weldment, G174-
1 fanwheel assembly, and F642 shaft weldment. Inspect condition of flex plates,
weldment flanges, and adjacent yokes. Verify proper fastener installation and unbroken
torque stripe.
2. Refer to Figure 18-12.
a. Fan Shaft: Using a #8 screw, attach vibration transducer and photocell (cables
pointed up) to mounting bracket(s). Secure bracket(s) to top of tailcone at the
forward nutplate, aiming photocell toward center of shaft.
b. Engine Shaft: Using appropriate hardware, attach photocell (cable pointed
outboard toward access door) to mounting bracket. Secure bracket to F020-1
frame assembly using MS21919WDG16 clamp and associated hardware, aiming
photocell toward center of shaft.
3. Install a target tape on each shaft weldment and align tape with a flange arm. Verify
photocell beam will hit target tape. (Tape becomes the 12 o'clock position.)
4. Route cable(s) forward into cabin; secure cables to cabin with duct tape.
5. Connect cable(s) to balancer. Verify security of installation.