Propeller

Question 1

Describe the original propeller?

Answer 1

Hartzell
4 bladed
Aluminum
105" diameter (104" minimum)
Full Feathering
Reversible
Constant Speed
Hydraulically Actuated

Question 2

Describe the MT Propeller?

Answer 2

Scimitar
5 bladed
Composite Blades
102.4" diameter (101.2" minimum)
Full Feathering
Reversible
Constant Speed
Hydraulically Actuated

Question 3

Why do we anchor the propeller when parked?

Answer 3

To prevent rotation of the RGB without lubrication.

Question 4

Propeller Limitations

Answer 4

Normal Operating 1,700 RPM
Max Transient 1,870 RPM
Max Reverse 1,650 RPM
Prohibited Ranged 350-950 RPM
Minimum Angle in flight is 6 degrees.

Question 5

Describe the pitch change mechanism?

3

Answer 5

Mounted in the propeller hub.

• Fixed Cylinder
• Sliding Piston
• Feathering Spring

Question 6

How is the propeller driven to fine pitch?

Answer 6

Oil pressure from the primary governor.

Question 7

How is the propeller driver to coarse pitch?

Answer 7

Feathering Spring and Counterweights.

Question 8

What is the primary low pitch stop set at?

Answer 8

19 degrees.

Question 9

CAWS “PROP LOW P” indicates?

Answer 9

Propeller pitch less that 6 degrees in flight.

Question 10

Max reverse pitch is?

Answer 10

17.5 degrees.

Question 11

Feather Pitch is?

Answer 11

79.6 degrees.

Question 12

What is the CSU?

What does it do?

What else does it contain?

Answer 12

The Constant Speed Unit.

Maintains propeller speed as regulated by the primary governor.

Also contains the NF governor.

Question 13

Where is the CSU located?

Answer 13

12 o’clock position on the RGB.

Question 14

What is the prop speed at Ground Idle?

Answer 14

1,060 approximately.

Question 15

How does the primary governor maintain prop speed?

Answer 15

Using a speeder spring with tension set for 1,700 RPM.

Flyweights adjust the pilot valve position to increase or decrease oil pressure in the propeller hub.

Question 16

Where is the NF governor located?

Answer 16

CO-located with the primary governor in the CSU at the 12 o’clock position on the RGB.

Question 17

How does the NF Governor limit propeller speed?

Limiting speed?

Answer 17

Vents PY air to the Fuel Control Unit (FCU) limiting engine/propeller speed.

Will limit NP to 1853 RPM (109%)

Question 18

What does the NF governor rely on to function?

Answer 18

The primary governor flyweights.

Question 19

Where is the Overspeed Governor located?

Answer 19

The 9 o’clock position on the RGB.

Question 20

What is the Overspeed Governors responsibility?

Answer 20

To prevent propeller overspeed in the event of a CSU failure.

Question 21

How does the overspeed governor function?

Limiting speed?

Answer 21

Uses a speeder spring and flyweights to detect an overspeed condition.

Will limit NP to 1802 RPM (106%).

Question 22

What does the Beta Valve do?

Answer 22

Allows propeller pitch to reduce to -17.5.

Upon reaching -17.5 the slip/beta feedback will pull the beta valve out blocking additional oil from reaching the hub.

Question 23

As the PCL is moved aft the beta valve allows propeller pitch to reduce to -17.5 degrees, futher movement of the PCL will?

Answer 23

Increase engine speed.

Question 24

How is propeller feathering accomplished?

Answer 24

The dump valve opens allowing oil pressure to drain from the prop hub.

(Using the feathering solenoid in the overspeed governor which is energized when the CL is moved to CUTOFF/FEATHER)

Question 25

What must be powered in order to feather the prop?

Answer 25

Battery Bus.

Question 26

How does the NF governor function?

Answer 26

Relies on primary governor flyweights.

Vents PY air to the FCU limiting engine/prop speed.

Question 27

What limits the propeller in reverse operations?

Answer 27

NF Governor.

Question 28

What speed does the NF Governor limit NP to?

RPM and %

Answer 28

1853 RPM

109%

Question 29

What speed does the Overspeed Governor limit NP to?

RPM and %

Answer 29

1802 RPM

106%