Propellers

Question 1

What is the function of a propeller?

Answer 1

Create thrust to pull or push an airplane through the air.

Question 2

How are some wooden propeller blades protected from wear and damage?

Answer 2

By metal tipping fastened to the leading edge and tip.

Question 3

What is the difference between a fixed pitch propeller and a controllable pitch propeller?

Answer 3

Fixed Pitch – Cannot be changed by the pilot. (Blade angle changed by the manufacturer)
Controllable Pitch Propeller – Can be changed by the pilot (Blade angle changed by the governor), some are provide with reverse pitch and feathering.

Question 4

What happens to the blade angle of a constant speed propeller during constant power dive?

Answer 4

The blade angle increases to prevent an overspeed.

Question 5

What are the functions of a constant speed propeller governor?

Answer 5

(1)It boosts engine oil pressure before it enters the propeller hub, (2)it senses rotational speed of the propeller,(3) and the adjusts the oil flow to the propeller hub to change pitch and therefore speed of the propeller.

Question 6

What is an unfeathering accumulator?

Answer 6

It is an oil accumulator used to

->provide oil pressure to unfeather a propeller

Question 7

What is meant when a propeller governor in an “on-speed” condition?

Answer 7

Is not accelerating or disaccelerating and the speeder spring and flyweight forces are in balance.

Question 8

How is a constant speed feathering propeller feathered?

Answer 8

By releasing oil pressure in the governor. The counterweights and feathering
spring move the propeller into feather or can be moved by the pilot moving the propeller control into the feathering detent.

Question 9

What is the purpose of propeller blade counterweights?

Answer 9

Forces the blade to a high pitch angle.

Question 10

To what do the terms alpha range and beta range pertain?

Answer 10

Those pertain to the operating modes of turboprop reversible-pitch propellers.

Question 11

What is the ALPHA range of a turboprop?

Answer 11

ALPHA – Operates in the standard constant speed mode (which is usualy in flight.)

Question 12

What is the BETA range of a turboprop?

Answer 12

BETA – Operates in the minimum thrust range and negative thrust or reverse thrust mode (which is usualy on ground).

Question 13

What two forces are balanced in a propeller governor in an on-speed condition?

Answer 13

Speeder spring and flyweight.

Question 14

What happens to a constant speed feathering propeller when the propeller governor oil pressure drops to zero?

Answer 14

The propeller will feather.

Question 15

How do you determine the reparability of a damaged propeller blade?

Answer 15

By reference to manufacturer’s maintenance manual.

Question 16

What systems are commonly used for propeller ice control?

Answer 16

Fluid (alcohol) and electrical heat applied to the propeller blade root.

Question 17

What propeller repairs can be performed by a certified mechanic with a powerplant rating?

Answer 17

-> Only MINOR REPAIRS and alterations,

major repairs or alterations are made in a certified repair station, the propeller manufacturer’s maintenance manual outlines the scope of repairs.

Question 18

How are wooden propellers generally cleaned?

Answer 18

Whit a brush or cloth and warm water with mild soap.

Question 19

Where would you find the correct method and technique for cleaning an aluminum propeller and Hub?

Answer 19

The propeller manufacturer’s manual.

Question 20

What type of nondestructive testing should be accomplished to a propeller after bending?

Answer 20

The procedures recommended by the manufacturer.

Question 21

What are the two criteria used by many manufactures to determine the amount of bend damage that can be repaired by cold bending of aluminim propellers?

Answer 21

The extent of the bend and its blade station location.

Question 22

How can repair file marks be removed from an aluminum propeller?

Answer 22

With a very fine sandpaper.

Question 23

When performing a static balance on a two bladed propeller, what positions must the propeller be placed in when measurements are taken?

Answer 23

Vertical and horizontal positions.

Question 24

What is a propeller protactor used for?

Answer 24

It is used to measure the propeller blade angle.

Question 25

What blade conditions can cause engine vibration?

Answer 25

Propeller out of track or balance, as well incorrect blade angle setting.

Question 26

What is blade tracking?

Answer 26

It is the position of the propeller blade tips relative to each other.

Question 27

What controls both manifold pressure and RPM on an engine equipped with a fixed pitch propeller?

Answer 27

The throttle.

Question 28

Other than maintaining constant speed, what are two actions of some controllable propellers?

Answer 28

Reverse pitch and feathering.