CFI Notebook

Question 1

What defines a fixed‑pitch propeller?

Answer 1

Blade angle is fixed and cannot be changed.

This means that the propeller cannot adjust its pitch during flight.

Question 2

What are the advantages of a fixed‑pitch propeller?

Answer 2

• Light
• Simple
• Inexpensive

These features make fixed-pitch propellers popular for certain aircraft.

Question 3

What is the main limitation of a fixed‑pitch propeller?

Answer 3

RPM varies with airspeed.

This can affect performance during different phases of flight.

Question 4

What does a climb prop optimize?

Answer 4

Takeoff and climb performance.

Climb props are designed for maximum efficiency during ascent.

Question 5

Why does a climb prop improve takeoff/climb?

Answer 5

Low pitch → high RPM → more horsepower.

This configuration allows for better acceleration and climb rates.

Question 6

What does a cruise prop optimize?

Answer 6

Cruise efficiency.

Cruise props are designed for optimal performance during level flight.

Question 7

Why does a cruise prop improve cruise?

Answer 7

High pitch → lower RPM → better fuel economy.

This setup reduces drag and improves fuel efficiency.

Question 8

What is a compromise fixed‑pitch prop?

Answer 8

Middle‑ground pitch; not ideal for climb or cruise.

It aims to balance performance across different flight phases.

Question 9

In a direct‑drive engine, how does prop RPM compare to engine RPM?

Answer 9

Prop RPM equals engine RPM.

This means the propeller spins at the same rate as the engine.

Question 10

In a geared engine, how does prop RPM compare to engine RPM?

Answer 10

Prop RPM differs from engine RPM.

Gear ratios can change the relationship between engine and propeller speeds.

Question 11

What is a ground‑adjustable propeller?

Answer 11

Pitch can be changed on the ground only.

This allows for adjustments before flight but not during.

Question 12

How many pitch settings did early adjustable props have?

Answer 12

Two: low and high.

These settings allowed for basic adjustments to performance.

Question 13

What do modern adjustable‑pitch props allow?

Answer 13

A full range of pitch settings.

This provides greater flexibility for different flight conditions.

Question 14

What defines a constant‑speed propeller?

Answer 14

Governor automatically varies pitch to maintain selected RPM.

This allows for optimal performance across various flight conditions.

Question 15

What system adjusts blade angle in a constant‑speed prop?

Answer 15

A governor using oil (and sometimes nitrogen) pressure.

This system ensures the propeller maintains the desired RPM.

Question 16

Why is a constant‑speed prop more efficient?

Answer 16

Keeps engine at optimal RPM for any condition.

This maximizes performance and fuel efficiency.

Question 17

What is the main disadvantage of a constant‑speed prop?

Answer 17

Heavier and more complex.

This can increase maintenance and operational costs.

Question 18

What does the throttle control?

Answer 18

Engine power (manifold pressure).

Adjusting the throttle affects the engine’s performance.

Question 19

What happens when throttle is increased?

Answer 19

Engine RPM rises → governor increases pitch.

This helps maintain optimal performance during acceleration.

Question 20

What does the propeller lever control?

Answer 20

Propeller pitch and desired RPM.

This allows the pilot to adjust the propeller’s performance.

Question 21

What happens when the prop lever is pushed forward?

Answer 21

Low pitch → high RPM.

This setting is typically used for takeoff and climb.

Question 22

What happens when the prop lever is pulled aft?

Answer 22

High pitch → low RPM.

This setting is used for cruise to improve fuel efficiency.

Question 23

What does the governor do once RPM is set?

Answer 23

Automatically adjusts blade angle to hold that RPM.

This ensures consistent performance during flight.

Question 24

What does the manifold pressure gauge measure?

Answer 24

Absolute pressure in the intake manifold (MAP).

This is crucial for understanding engine performance.

Question 25

What three factors determine **propeller blade angle of attack**?

Answer 25

* Blade angle * Blade speed * Air velocity ## Footnote These factors influence the lift and drag experienced by the propeller.

Question 26

What defines a **fixed‑pitch propeller**?

Answer 26

Blade angle is fixed and cannot be changed. ## Footnote This means that the propeller cannot adjust its pitch during flight.

Question 27

What is the main **advantage** of a fixed‑pitch prop?

Answer 27

* Light * Simple * Inexpensive ## Footnote These characteristics make fixed-pitch props popular in smaller aircraft.

Question 28

What is the main **disadvantage** of a fixed‑pitch prop?

Answer 28

RPM varies with airspeed. ## Footnote This can lead to inefficiencies in different flight conditions.

Question 29

What does a **climb prop** optimize?

Answer 29

Takeoff/climb: low pitch → high RPM. ## Footnote This configuration allows for better performance during ascent.

Question 30

What does a **cruise prop** optimize?

Answer 30

Cruise efficiency: high pitch → lower RPM. ## Footnote This setup enhances fuel efficiency during level flight.

Question 31

What defines a **constant‑speed propeller**?

Answer 31

Governor automatically varies pitch to maintain selected RPM. ## Footnote This allows for optimal engine performance across various flight conditions.

Question 32

What system adjusts blade angle in a **constant‑speed prop**?

Answer 32

A governor using engine oil pressure. ## Footnote The governor ensures that the propeller maintains the desired RPM.

Question 33

Why is a **constant‑speed prop** more efficient?

Answer 33

Allows engine to run at optimal RPM for any condition. ## Footnote This results in better fuel efficiency and performance.

Question 34

What does the **throttle** control?

Answer 34

Engine power (manifold pressure). ## Footnote Adjusting the throttle changes the power output of the engine.

Question 35

What does the **propeller lever** control?

Answer 35

Propeller pitch → sets desired RPM. ## Footnote This lever allows the pilot to adjust the propeller's performance.

Question 36

What happens when the **prop lever** is moved forward?

Answer 36

Low pitch → high RPM. ## Footnote This setting is typically used for takeoff and climb.

Question 37

What happens when the **prop lever** is moved aft?

Answer 37

High pitch → low RPM. ## Footnote This setting is used for cruising to enhance efficiency.

Question 38

What is the governor’s job once **RPM** is set?

Answer 38

Automatically adjusts blade angle to hold selected RPM. ## Footnote This ensures consistent engine performance.

Question 39

What does the **manifold pressure gauge** measure?

Answer 39

Absolute pressure in the intake manifold (MAP). ## Footnote This gauge helps monitor engine performance.

Question 40

What three factors determine **propeller blade AoA**?

Answer 40

* Blade angle * Blade speed * Air velocity ## Footnote These factors influence the lift and efficiency of the propeller.

Question 41

What does the governor balance to maintain **RPM**?

Answer 41

Engine torque vs. aerodynamic load. ## Footnote This balance is crucial for stable engine operation.

Question 42

What happens when **airspeed increases**?

Answer 42

Prop speeds up → flyweights out → pitch increases. ## Footnote This adjustment helps maintain optimal performance.

Question 43

What happens when **airspeed decreases**?

Answer 43

Prop slows → flyweights in → pitch decreases. ## Footnote This adjustment helps prevent engine strain.

Question 44

Why cycle the prop during **warm‑up**?

Answer 44

Verify operation and circulate warm oil through the governor. ## Footnote This ensures that the propeller system is functioning correctly.

Question 45

What do pilots look for during **prop cycling**?

Answer 45

* RPM drop * Oil pressure change * Manifold pressure increase ## Footnote These indicators help ensure the propeller is operating as expected.