Propellers

Question 1

What type of device is used on propeller blades to remove ice that has formed on them?

Answer 1

Electrically heated deicer boots.

Question 2

What is used to prevent ice forming on a propeller blade?

Answer 2

A mixture of ethylene glycol and isopropyl alcohol slung out along the blades.

Question 3

Should an adjustable-pitch propeller be in high pitch or in low pitch for takeoff?

Answer 3

In low pitch.

Question 4

What is done to cause a Hydromatic propeller to feather?

Answer 4

High-pressure engine oil is directed into the propeller through the governor.

Question 5

What is done to cause a McCauley propeller to feather?

Answer 5

Oil is allowed to drain out of the propeller.

Question 6

Does centrifugal twisting moment on a propeller blade tend to move the blades toward high pitch or toward low pitch?

Answer 6

Toward low pitch.

Question 7

Do the flyweights on a propeller tend to move the blades toward high pitch or toward low pitch?

Answer 7

Toward high pitch.

Question 8

What is the difference between a controllable propeller and a constant-speed propeller?

Answer 8

Basically, it is the control system. A controllable-pitch propeller uses a manually operated oil valve to control the pitch, and a constant-speed propeller uses a governor to control the valve.

Question 9

When making a magneto check on an engine equipped with a constant-speed propeller, should the propeller control be in the LOW PITCH or the HIGH PITCH position?

Answer 9

It should be in the LOW PITCH position.

Question 10

What can be done to prevent the front cone from bottoming when installing a propeller on a splined shaft?

Answer 10

Install a spacer behind the rear cone to move the propeller forward on the shaft.

Question 11

What is the purpose of the small holes that are drilled in the end of a wooden propeller?

Answer 11

These holes vent the inside of the propeller blade and allow moisture that collects in the wood to be released.

Question 12

What is the function of the snap ring inside the hub of a propeller that is mounted on a tapered or splined shaft?

Answer 12

The snap ring allows the propeller to be pulled off of the shaft when the retaining nut is backed off.

Question 13

What is adjusted inside the governor for a constant-speed propeller to change the speed at which the propeller is operating?

Answer 13

The compression of the speeder spring.

Question 14

What is the function of the accumulator that is used with some McCauley feathering propellers?

Answer 14

The accumulator stores oil under pressure when the engine is operating normally. This oil is used to help the propeller blades move toward low pitch when the propeller is being unfeathered.

Question 15

What is meant by the beta range of operation of a turboprop propeller?

Answer 15

This is the mode of ground operation, and it includes starting, taxiing, and ground reverse operation.

Question 16

What is meant by the alpha range of operation of a turboprop propeller?

Answer 16

This is the in-flight mode of operation from takeoff to landing.

Question 17

Is the flat surface of a propeller blade the face of the blade or the back of the blade?

Answer 17

It is the face of the blade.

Question 18

What keeps a McCauley feathering propeller from feathering when the engine is shut down on the ground?

Answer 18

A spring-loaded latch mechanism prevents the blades moving into the feather position when the engine is shut down on the ground. In the air, aerodynamic forces keep the propeller rotating, and centrifugal force holds the blades unlatched so they can move to the feather position when oil pressure is taken out of the propeller.