17.6 Propeller Maintenance

Question 1

Where is static balancing carried out

Answer 1

Off aircraft

Question 2

Which propellers are normally not dynamically balanced

Answer 2

Small propellers

Question 3

A body rotating about a fixed point is what

Answer 3

Static balance

Question 4

Balancing propeller to reduce moment of imbalance is known as

Answer 4

Dynamic balancing

Question 5

When must dynamic balancing be carried out on

Answer 5

Running engine

Question 6

What is the universal blade protractor used to measure

Answer 6

• propeller blade angle at specific blade station to ensure propeller is properly adjusted

Question 7

What is the protractor frame made out of

Answer 7

Aluminium

Question 8

Aerodynamic balancing are used on what kind of propellers

Answer 8

• necessary for propellers with high performance

Question 9

Reference station is normally set at either 30, 36 or 42 inch measurement on the propeller blade (T or F)

Answer 9

T

Question 10

What is blade tracking

Answer 10

Ability of one blade to follow the same plane of rotation

Question 11

What are the 2 main methods to check a blades tracking

Answer 11

• flat bench method
• block or pointer method

Question 12

To check tracking, place smooth board under tip of lower blade

Answer 12

True

Question 13

Explain flat tracking method

Answer 13

• smooth board placed under tip of lower blade and paper taped to it
• draw line with pencil
• lines should be separated by not more than 3mm

Question 14

Explain block or pointer tracking method

Answer 14

• means of a heavy block or pointer method
• within 1/16 inch from opposite blades track

Question 15

Airworthy damage limits described within?

Answer 15

AMM ATA chapter 61

Question 16

Explain erosion

Answer 16

• loss of material from blade surface by small particles like sand/water etc

Question 17

Ultrasonic inspections can be carried out on what materials

Answer 17

Wood, composites, ferrous, non-ferrous metals

Question 18

Explain Eddy current inspection

Answer 18

• generates and measures an electric field that detects flaws or slightly be.ow surface of component being inspected

Question 19

Cracks in the pain across the blade is a sign of what

Answer 19

Flexural vibrations

Question 20

Indentations in the metal tipping can be filled by what

Answer 20

Soldering

Question 21

Surface damage to wooden propeller blades can be repaired using what

Answer 21

Wood filler or mix of sawdust and aeroglue

Question 22

Metal blades require thorough inspection after cleaning when

Answer 22

Every 100 hours or annually

Question 23

As a protection against corrosion what can be applied to the hub after cleaning

Answer 23

Lubricant spray

Question 24

Sub-classification of damage may also be sub-divided as what

Answer 24

• skin perforated damage
• skin not perforated damage

Question 25

Explain airworthy damage and unairworthy damage

Answer 25

Airworthy - can be repaired in field
Unairworthy - damage exceeds limits of airworthy damage

Question 26

What material is the tap test carried out on and with what

Answer 26

Composite blades with a metal coin

Question 27

Why is the erosion strip attached to the composite blade LE for

Answer 27

• to show erosion effect on blade

Question 28

Corrosion on metal propeller components can be classified into 3 types

Answer 28

• surface corrosion
• pitting
• intergranular corrosion

Question 29

Metal propellers must be checked thoroughly after how long

Answer 29

• 100 hours/annually

Question 30

Is repair permissible on blade root

Answer 30

No

Question 31

Repair of damage

Answer 31

10x depth of nick for the leading and trailing edge

30x depth for the blade face and back

Question 32

Explain steel propellers

Answer 32

• extremely durable and resistant to damage

Question 33

What are static checks

Answer 33

• checks carried out without the need to run engines