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PPL - AGK > Propeller & Variable Pitch Propeller > Flashcards

Propeller & Variable Pitch Propeller Flashcards

1
Q

Creating forward movement from a propeller is the method of turning ____ motion into ____

A

Method of turning reciprocal motion into thrust

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2
Q

What are the 2 types of propeller

A
  1. Fixed pitch
  2. Variable pitch
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3
Q

The amount of lift produced by a propeller blade is dependant on what 2 factors

A
  1. Speed
  2. AoA
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4
Q

Why is an propeller designed to have less AoA at the tip than at the hub

A

Tips travel faster
More lift would be produced
More AoA at hub than at tips

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5
Q

If a propeller blade had the same AoA across its entire length, which section of the propeller would produce more lift?

A

THE TIP
The tip has greater distance to travel
It travels faster so would produce more lift with the same AoA as the centre of the blade

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6
Q

At the hub of a propeller blade, AoA is HIGHER or LOWER than the AoA at the tip

A

Hub = HIGHER
Tip = LOWER

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7
Q

The AoA of a propeller blade is dependent on which 2 factors

A
  1. Propeller Pitch (Blade angle)
  2. Forward Velocity
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8
Q

You can determine how far a propeller moves forward in one revolution based on what?

A

GEOMETRIC PITCH

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9
Q

The efficiency of fixed pitch propeller varies with what

A

AIRSPEED

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10
Q

Fixed pitched propeller in a climb, assuming power (throttle) constant

Airspeed INCREASES or DECREASES

A

DECREASES

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11
Q

Fixed pitched propeller in a climb, assuming power (throttle) constant

Relative airflow angle INCREASES or DECREASES

A

INCREASES

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12
Q

Fixed pitched propeller in a climb, assuming power (throttle) constant

Propeller AoA INCREASES or DECREASES
This has what effect on efficiency

A
  1. AoA INCREASES
  2. Efficiency DECREASES
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13
Q

Fixed pitched propeller in a climb, assuming power (throttle) constant

Propeller is EASIER or HARDER to push through the air
This has what effect on engine workload

A
  1. HARDER
  2. Workload INCREASES
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14
Q

Fixed pitched propeller in a climb, assuming power (throttle) constant

Engine RPM INCREASES or DECREASES

A

DECREASES

AoA has increased, prop takes bigger bites of the air
This takes more effort. Engine works harder and turns more slowly

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15
Q

Fixed pitched propeller in a descent, assuming power (throttle) constant

Airspeed INCREASES or DECREASES

A

INCREASES

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16
Q

Fixed pitched propeller in a descent, assuming power (throttle) constant

Relative airflow angle INCREASES or DECREASES

A

DECREASES

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17
Q

Fixed pitched propeller in a descent, assuming power (throttle) constant

Propeller AoA INCREASES or DECREASES
This has what effect on efficiency

A
  1. AoA DECREASES
  2. Efficiency INCREASES
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18
Q

Fixed pitched propeller in a descent, assuming power (throttle) constant

Propeller is HARDER or EASIER to push through the air
This has what effect on engine workload

A
  1. EASIER
  2. Workload DECREASES
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19
Q

Fixed pitched propeller in a descent, assuming power (throttle) constant

Engine RPM INCREASES or REDUCES

A

INCREASES

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20
Q

On an RPM gauge what is meant by the following

  1. Green Arc
  2. Red Line
A
  1. Normal Operating Range
  2. Never Exceed
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21
Q

What are 2 examples of propeller aerofoil damage
What effect does this have on efficiency

A
  1. Stone Chips
  2. Tip Damage
  3. Propeller less efficient
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22
Q

A propeller under high stress loads could suffer from what

A

STRUCTURAL FATIGUE

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23
Q

If a small part of a propeller tip were to detach, what could this result in

A

SEVERE VIBRATION

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24
Q

What is a key reasons for an engineering filing out nicks on a propeller blade

A

Prevent fatigue cracks forming and spreading

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25
Q

A variable pitch propeller

With a higher AoA;
1. ____ Lift
2. ____ to push through the air

A
  1. GREATER LIFT
  2. MORE DIFFICULT
26
Q

A variable pitch propeller creates

With a lower AoA;
1. ____ Lift
2. ____ to push through the air

A
  1. LESS LIFT
  2. LESS DIFFICULT
27
Q

A variable pitch propeller

Why do you change the blade angle at different airspeeds

A

Maintain best AoA

28
Q

A variable pitch propeller

With a low forward speed (start of take off run), what happens to the flyweight, and what pitch angle is selected as a result

A
  1. MOVE IN
  2. FINE PITCH

Low blade angle

29
Q

A variable pitch propeller

With a high forward speed (high speed descent), what happens to the flyweight, and what pitch angle is selected as a result

A
  1. MOVE OUT
  2. COARSE PITCH

High blade angle

30
Q

A variable pitch propeller

Beyond what 2 limits will a variable pitch propeller become inefficient

A
  1. FINE PITCH STOP
  2. COARSE PITCH STOP
31
Q

The mechanism that does automatic blade angle adjustment is known as what

A

CONSTANT SPEED UNIT
(CSU)

32
Q

Variable pitched propeller in a climb, with power (throttle) constant

Propeller adjusts blade angle to INCREASE or REDUCE AoA

A

REDUCE AoA

33
Q

Variable pitched propeller in a climb, with power (throttle) constant

When the propeller adjusts the blade angle, this makes the propeller EASIER or HARDER to push through the air
What effect does this have on engine workload

A
  1. EASIER
  2. REDUCED workload
34
Q

Variable pitched propeller in a climb, with power (throttle) constant

If the propeller blade angle is adjusted and engine workload reduces, what effect does this have on RPM

A

RPM RECOVERS

Engine RPM reduces on climb
Blade angle reduces the blade AoA
Propeller is easier to push through air, reducing engine workload
This allows RPM to recover

35
Q

In a CSU unit, what mechanism does oil pressure act against

36
Q

In a CSU Unit

  1. What does the spring try to do to the propeller pitch
  2. What is the oil pressure doing in response to this
A
  1. Force fully coarse pitch
  2. Acts against spring (fine pitch)
37
Q

Variable pitch propeller

If a pilot sets low RPM, what pitch angle is set

A

LOW RPM = HIGH PITCH

High pitch = Coarse Pitch

38
Q

Variable pitch propeller

If a pilot sets high RPM, what pitch angle is set

A

HIGH RPM = LOW PITCH

Low pitch = Fine pitch

39
Q

With an increased RPM in a CSU, what will happen to the flyweight

A

MOVE OUTWARDS

40
Q

In a CSU, if the flyweight move out, what effect does this have on;

  1. Oil pressure
  2. Spring position
A
  1. DECREASED PRESSURE
  2. COARSE AoA
41
Q

In a CSU, if the flyweight moves in, what effect does this have on;

  1. Oil pressure
  2. Spring position
A
  1. INCREASED PRESSURE
  2. FINE AoA
42
Q

Variable pitch propeller

An aircraft accelerating (descending) results in MORE or LESS inflow, which INCREASES or DECREASES the effective AoA. The flyweight will move IN or OUT

A
  1. MORE inflow
  2. DECREASED AoA
  3. OUT
43
Q

Variable pitch propeller

An aircraft decelerating (climbing) results in MORE or LESS inflow, which INCREASES or DECREASES the effective AoA. The flyweight will move IN or OUT

A
  1. LESS inflow
  2. INCREASED AoA
  3. IN
44
Q

Variable pitch propeller

As AoA decreases, the propeller is doing MORE or LESS work. RPM INCREASES or DECREASES

A
  1. LESS work
  2. INCRESED rpm
45
Q

Variable pitch propeller

As AoA increases, the propeller is doing MORE or LESS work. RPM INCREASES or DECREASES

A
  1. MORE work
  2. DECREASED rpm
46
Q

Variable pitch propeller

A pilot adjusts RPM control to LOW RPM. What effect does this have on the prop pitch

A

MORE COARSE

47
Q

Variable pitch propeller

A pilot adjusts RPM control to HIGH RPM. What effect does this have on the prop pitch

48
Q

What colour is the RPM lever

49
Q

What colour is the Throttle lever

50
Q

Constant Speed Unit (CSU)

The blue lever controls ____ and instrumentation shows ____ via the ____ gauge

A
  1. RPM
  2. RPM
  3. RPM gauge
51
Q

Constant Speed Unit (CSU)

The black lever controls ____ and instrumentation shows ____ via the ____ gauge

A
  1. POWER
  2. POWER PRODUCED
  3. MANIFOLD PRESSURE GAUGE
52
Q

What does a Manifold Pressure (MAP) gauge messure

A

Pressure in the throat of the carburettor

Mounted after the butterfly valve

53
Q

When the butterfly vavle is shut, the MAP gauge will indicate a HIGH or LOW pressure reading

A

LOW READING

54
Q

When the butterfly valve is fully open, the MAP gauge will indicate a HIGH or LOW pressure reading

A

HIGH READING

55
Q

Under what circumstance may a MAP gauge indicate a much higher than atmospheric pressure

A

Super or Turbo Charged engines

56
Q

What happens to the engine if the wrong order of altering the MAP and RPM is applied?

A

LABOURED ENGINE

57
Q

CSU and Engine management

What are the 3 steps to INCREASE power

A
  1. Increase REVS
  2. Increase PRESSURE
  3. Check MIXTURE

REMEMBER: Increase R P M, throttle FORWARD RPM
–> RPM –>

58
Q

CSU and Engine management

What are the 3 steps to DECREASE power

A
  1. Check MIXTURE
  2. Reduce PRESSURE
  3. Reduce REVS

REMEMBER: Decrease RPM, throttle BACK RPM
<– RPM <–

59
Q

Where can a pilot find the allowable combinations of MAP and RPM for a given flight configuration

A

PIlot Operating Handbook
(POH)

60
Q

CSU and Engine Management

During descent, what will happen to atmospheric pressure
What will happen to MAP if unchecked

A
  1. INCREASE
  2. INCREASE
61
Q

CSU and Engine Management

During ascent, what will happen to atmospheric pressure
What will happen to MAP if unchecked

A
  1. DECREASE
  2. DECREASE
62
Q

What are 3 possible failure scenarios of a variable pitch propeller

A
  1. Oil Pressure
  2. CSU
  3. Pilot Action

PPL - AGK (20 decks)

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