Rotor Track and Balance Product Support ACES SystemsTEC

Rotor Track and Balance Product Support ACES Systems/TEC Aviation Division support@acessystems. com 06/06/2011 #1

Overview Q Rotor Balance Q Types of Balance Q Equipment Q Installation Q Data Acquisition and Making Adjustments Q Troubleshooting 06/06/2011 #2

Rotor Balance Q What is an imbalance? Q Advantages and disadvantages Q Causes of imbalance Q Other sources of vibration 06/06/2011 #3

Rotor Balance What is an imbalance? Q A condition where there is more weight distributed on one side of a rotating component than on the other side 06/06/2011 #4

Rotor Balance Advantages Q Simple Q Cost efficient Q Cost effective 06/06/2011 #5

Rotor Balance Disadvantages Q Noise Q Vibration 06/06/2011 #6

Rotor Balance Causes of Imbalance Q Manufacturing tolerances Q Shimming and alignment Q Rotor track Q Static track Q Dynamic track 06/06/2011 #7

Rotor Balance Rotor Track Q Static track Q Perfect track if all blades produce the same lift Q Assumes that blade twist, profile, and stiffness are equal on all blades Q Assumed then to give equal lift on all surfaces of the blade 06/06/2011 #8

Rotor Balance Rotor Track Q Dynamic track Q How the rotors fly during operation Q More important to sacrifice a perfect tip path track for a rotor that is perfectly balanced 06/06/2011 #9

Rotor Balance Other Sources of Vibration Q Mechanical looseness Q Misalignment Q Track Q Worn bearings 06/06/2011 #10

Types of Balance Q Dynamic track and balance Q Purpose of balancing Q Types of imbalance 06/06/2011 #11

Types of Balance Dynamic Track and Balance Q First introduced in the late 1950’s Q Operators found that virtually all statically balanced rotors were out of balance dynamically when installed. 06/06/2011 #12

Types of Balance Purpose of Balancing Q Static Q Knife edge Q Suspended arbor Q Bubble balance 06/06/2011 #13

Types of Balance Purpose of Balancing Q Dynamic Q Performed during operation Q All of the rotating components are balanced as an assembly 06/06/2011 #14

Types of Balance Types of Imbalance Q Mass imbalance Q Distribution of the mass Q Spanwise or chordwise Q Aerodynamic imbalance Q Out-of-track condition exists 06/06/2011 #15

Types of Balance Benefits to Dynamic Balance Q Enhance comfort Q Reduce wear Q Increase safety by reducing component stress Q Lower operating costs 06/06/2011 #16

Equipment Q Sensors Q Tach sources Q Vibration measurements Q Amplitude and phase 06/06/2011 #17

Equipment Sensors Q Accelerometers Q Displacement sensors Q Velocity sensors 06/06/2011 #18

Equipment Accelerometers Q Measure acceleration Q Typically reported in g’s Q More sensitive to higher frequencies Q Directly related to force caused by unbalance Q Used in balancing (after conversion to velocity or displacement) 06/06/2011 #19

Equipment Displacement Sensors Q Measure change in position Q Typically reported in mils (. 001 of an inch) peak to peak Q More sensitive to Low frequencies Q Directly related to movements due to imbalance Q Seldom used in balance (however, displacement units are often used) 06/06/2011 #20

Equipment Velocity Sensors Q Measure velocity Q Typically reported in IPS peak Q More sensitive to medium frequencies Q Directly related to energy from imbalance Q Often used in balance 06/06/2011 #21

Equipment Sensor Construction 06/06/2011 #22

Equipment Tach Sources Q Magnetic pickup Q Phototach 06/06/2011 #23

Equipment Magnetic Pickup 06/06/2011 #24

Equipment Phototach 06/06/2011 #25

Equipment Vibration Measurements Q Amplitude and phase Q Correlation between the trigger of the tach source and the time until the sensor registers the maximum amplitude. Q The result will be a phase angle in degrees or time (clock angle) 06/06/2011 #26

Installation Q Sensor Q Tach Source Q Tip Targets 06/06/2011 #27

Installation Sensor 06/06/2011 #28

Installation Tach Source 06/06/2011 #29

Installation Tip Targets 06/06/2011 #30

Installation Optical Tracker Q Optical devices obsolete tip targets 06/06/2011 #31

Data Acquisition and Making Adjustments Q Polar plotting Q Automated solutions Q Rotor track and balance Q Rules 06/06/2011 #32

Data Acquisition and Making Adjustments Polar Plotting Q IPS and phase values are taken from the analyzer and manually plotted on charts to obtain a correction. 06/06/2011 #33

Data Acquisition and Making Adjustments Automated Solutions Q The analyzer is used to collect the phase and IPS readings then calculates a solution Q The calculated solution is then implemented by the user eliminating manual calculations 06/06/2011 #34

Data Acquisition and Making Adjustments Rotor Track and Balance Q Pitch links Q Tab Q Sweep Q Tip weight Q Hub weight Q Blade chordwise weight 06/06/2011 #35

Data Acquisition and Making Adjustments Pitch Links Q Changes the lift of the blade by adjusting the angle of attack at the rotor hub Q Characteristically changes the tip path plane throughout speed range Q Characteristically has large drag changes resulting in a strong effect on lateral balance 06/06/2011 #36

Data Acquisition and Making Adjustments Pitch Links Eurocopter SA 330 Puma AW 139 Agusta. Westland 06/06/2011 #37

Data Acquisition and Making Adjustments Tab Q Changes the lift of the blade by adjusting the twist in the blade aerodynamically Q Characteristically changes the tip path plane at higher airspeeds Q Characteristically has small drag changes resulting in little affect on the lateral vibrations 06/06/2011 #38

Data Acquisition and Making Adjustments Tab Eurocopter EC 135 Agusta. Westland AW 139 06/06/2011 #39

Data Acquisition and Making Adjustments Sweep Q Changes the balance of the rotor head by adjusting the center of mass Q Characteristically changes the mass at all air speeds Q Characteristically it has little effect on the lift of the rotor and the vertical vibration 06/06/2011 #40

Data Acquisition and Making Adjustments Sweep Bell 206 Series Sweep Adjustment 06/06/2011 #41

Data Acquisition and Making Adjustments Tip Weight Q Changes the mass of the rotor head by adjusting blade weight Q Characteristically no change to tip path plane Q Characteristically has a large effect on lateral vibration 06/06/2011 #42

Data Acquisition and Making Adjustments Tip Weight M/R MI 8/17/24 Tip Weight Adjustment T/R 06/06/2011 #43

Data Acquisition and Making Adjustments Hub Weight Q Changes the mass of the rotor by changing rotor head mass Q Characteristically has large effects on the lateral vibration Q Characteristically has no effect on tip path plane 06/06/2011 #44

Data Acquisition and Making Adjustments Tip Weight BO 105 M/R Hub Weight - Hollow Bolt EC 155 M/R Hub Weight - Washer 06/06/2011 #45

Data Acquisition and Making Adjustments Hub Weight Bell 407 T/R Irregular Bell 206 Series T/R Regular 06/06/2011 #46

Data Acquisition and Making Adjustments Blade Chord Weight Q Changes the center of gravity of the blade Q Characteristically changes tip path with changes in collective force Q Characteristically has large effects on verticals Q Characteristically has large effects on laterals at ground/hover and in letdowns 06/06/2011 #47

Data Acquisition and Making Adjustments Blade Chord Weight Bell 407 Chord/Product Weight 06/06/2011 #48

Troubleshooting Q Polar Plotting - Human error Q Worn components Q Structural resonance 06/06/2011 #49

Troubleshooting Polar Plotting Q Human Error Q The result of an adjustment increases the IPS or the moveline 180 degrees out 06/06/2011 #50

Troubleshooting Worn Components Q A specific vibration level is achieved and continued adjustments result in IPS levels that do not change and phase angle walks around the chart. Q A large amount of weight added to a location results in no change in IPS or phase 06/06/2011 #51

Troubleshooting Structural Resonance Q Unrepeatable reading Q Adjustments result in varying results Q Phase angles and IPS levels are very erratic and unpredictable when known good solutions are implemented. 06/06/2011 #52

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