17.2 - Propeller Construction - 4q

Question 1

What material is a modern propeller made from?

Answer 1

Aluminium propellers are the most widely used types of propellers in aviation.

Steel propellers are found primarily on transport aircraft

Question 2

Which is the best propeller material for engine cooling?

Answer 2

Aluminium propellers

Question 3

Where are the cuffs of a blade and what are they for?

Answer 3

1. Reduce Aerodynamic losses (airfoil section is carried all the way from the tip to the hub by means of blade cuffs)
2. Increase cooling airflow into the engines

Question 4

Where are the blade stations located?

Answer 4

A blade is broken up into segments which are located by station numbers in inches from the centre of the blade hub (out towards the tip)

Question 5

Describe the following parts of a propeller:

Blade Shank

Answer 5

The blade shank is the thick, rounded portion of the propeller blade near the hub, which is designed to give strength to the blade

Question 6

Describe the following parts of a propeller:

Blade Butt

Answer 6

The blade butt, also called the blade base or root, is that end of the blade, which fits in the propeller hub.

Question 7

Describe the following part of a prop:

Blade Back

Answer 7

The cambered side of a blade is called the blade back.

Question 8

Describe the following parts of a prop:

Blade Face

Answer 8

The flat side of the blade is called the blade face

Question 9

Which type of aircraft use fixed pitch propellers?

Answer 9

Light Aircraft

The fixed-pitch propeller is used on aircraft of low power, speed, range, or altitude.

Question 10

Where is the lowest blade angle (root or tip)?

Answer 10

Tip

Question 11

What are the 3 ways of installing a propeller to a crankshaft?

Answer 11

1. The flanged shaft (a)
2. The tapered shaft (b)
3. The splined shaft (c)

Question 12

What is used to prevent a propeller being installed wrongly?

Answer 12

Dowel pins may be used so can only be fit in one position

or as specified in the aircraft or engine maintenance manual

Question 13

What is the minimum contact area on a tapered crankshaft and on a splined crankshaft?

Answer 13

minimum of 70% contact area for both tapered crankshaft and splined crankshaft

Question 14

Which type of crankshaft installation is used for a low powered aircraft?

Answer 14

Tapered crankshaft

Question 15

Which type of crankshaft installation is used for a high powered aircraft?

Answer 15

Flanged crankshaft

Question 16

What is the greatest force that a propeller is subjected to?

Answer 16

Centrifugal force

Question 17

What types of wood are used on wooden propellers and which wood is most popular? (5)

Answer 17

Many woods such as:

• Mahogany
• Cherry
• Black Wallnut
• Oak
• Birch

Birch is the most widely used

Question 18

Usually between five and nine separate layers of wood are used, each about 3/4 inch thick in the constrution of the blade.

These layers are glued together with a waterproof, _________ and allowed to set.

These planks of wood which are glued together are called a _______

Answer 18

resinous glue

Blank

Question 19

The blank is then roughly shaped to the approximate size and shape of the propeller.

The roughly shaped blank is called a ______

Answer 19

White

Question 20

A metal tipping is fastened to most of the leading edge and tip of each blade to protect the _____________

The most common material used is ______

Answer 20

propeller from damage

brass

Question 21

The primary purpose of the blade cuffs are to …

Answer 21

increase cooling airflow to the engine

Question 22

The cambered side of a blade is called the blade _____

The flat side of the blade is called the blade ______

Answer 22

The cambered side of a blade is called the blade back

The flat side of the blade is called the blade face

Question 23

Where is information about the prop

builders name

model designation

serial no.

type cert no.

production cert no.

printed?

Answer 23

The information should be printed on the propeller hub or on the butts of the blades

Question 25

Explain the McCauley Designation system:

1B90/CM7246

Answer 25

1B90/CM7246

1B90 = basic designation

CM = type of crankshaft

72 = diameter of the propeller in inches

46 = geometric pitch

Question 26

geometric pitch is taken at the ___% station

Answer 26

75% station

Question 27

Any defects found on a propeller should be repaired in accordance with the _______

Answer 27

Engine manufacturer’s recommendations

Question 28

Use the following torque values when tightening bolts on a flanged shaft:

metal props = _______

wooden props = ______

Answer 28

metal props = 35 foot-pounds or higher

wooden props = 25 foot-pounds or higher

Question 29

A full spinner prop consists of what forward and aft of the prop

Answer 29

Question 30

A ____________ inspection of the keyway area is advisable each time the propeller is removed

(tapered shaft)

Answer 30

dye-penetrant

Question 31

Inspect the hub and bolts with _______ or _______ inspection methods

Answer 31

dye penetrant or magnetic particle

Question 32

The fit of the hub on the crankshaft should be checked by the use of transfer ink such as _______

Answer 32

Engineer’s blue

Question 33

Inspect the splines on the crankshaft and on the hub for wear by using a ‘‘go/no-go’’ gauge

The crankshaft or spline is serviceable if the gauge cannot be inserted between the splines for more than ____%

Answer 33

20%

Question 34

If no engineer blue is transferred from the rear cone during the transfer check, a condition known as _________ exists

Answer 34

rear cone bottoming

Question 35

When the hub is loose on the shaft after the retaining nut has been torqued and there is no tranfer of Engineer’s Blue to the front hub seat.

Correct front cone bottoming using a _____

Answer 35

spacer

Question 36

Fiber lock nuts, which require no safetying, but the nuts. should be _______

Answer 36

replaced each time the prop is removed