Propeller Systems (Variable Pitch) Flashcards

1
Q

What are the definitions of the following terms?
Coarse Pitch
Fine Pitch
Feather Pitch
Revering Pitch

A
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2
Q

How is pitch changed in a variable speed prop?

A

Via a hydraulic system using engine oil controlled by the propeller governor to change the pitch of the blades

In a non-feathering system (single engines), the pitch is increased with increased oil pressure

In a full-feathering system (multi-engines), the pitch is decreased with increased oil pressure

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3
Q

As you add oil to a full-feathering system, what happens to the pitch of the blades?

A

The pitch is decreased/becomes more fine

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4
Q

As you add oil into a non-feathering system, what happened to the pitch of the blades?

A

The pitch increases/becomes more coarse

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5
Q

What kind of pitch would moving the lever full-forward give?

A

Fine = Low angle of incidence = low/small angle of attack

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6
Q

What do you use in aircraft with a variable prop instead of RPM?

A

Manifold Pressure

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7
Q

If the outside air pressure is 29.92, what will the Manifold Pressure guage read at full throttle?

A

Just below 30”. The MP guage should be reading close to whatever the pressure it. There is a little bit of loss but should be close.

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8
Q

If the throttle is pulled to idle, what will the MP guage read regardless of the outside air pressure?

A

Super low, around 10”

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9
Q

When there is a MP guage, what do it and the RPM guage mean now?

A

MP: The power I have availible
RPM: How efficiently I am using that power with the pitch of my prop

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10
Q

What is the perfect angle of attack for a prop blade?

A

2 to four degrees

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11
Q

While within the governing range, if there are any changes in engine power and/or airspeed, the governer will…

A

Maintain a steady RPM if a constant-speed propeller system is used

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12
Q

What drives the propeller blades of a full-feathering system towards coarse pitch?

A

Counterweights and internal springs

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13
Q

Oil pressure boosted by the governor has the purpose of moving the propeller towards…

A

coarse pitch in a single-engine aeroplane

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14
Q

As the oil pressure drops on a constant-speed non-feathering system, the governor would make the propeller…

A

full fine

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15
Q

What happens to a centrifugal counterweight and springs propeller system when the engine quits during flight?

A

Because the engine is still windmilling, the gear still drives the governor. The governor will still operate as usual and change the blade angle so as to keep the RPM setting.

So the blades move towards the selected propeller RPM by becoming more fine

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16
Q

What drives the governor?

A

The engine

17
Q

After startup a twin-engine aeroplane’s oil pressure…

A

rises, moving the propeller into fine pitch

18
Q

During takeoff in a constant-speed aeroplane, the propeller blades initially move towards…

A

Full fine for maximum power (kayak analogy)

19
Q

Which aeroplane operation would move the propeller pitch towards the high pitch stop?

A

High speed descent

20
Q

During an engine failure in a twin-engine, what guage is best to shaw which engine has failed?

A

EGT, temperature will drop because no combustion = no heat