Propeller Principles Flashcards
What drag acts 90 degrees to the axis of rotation on a propeller aircraft?
Torque.
What is the propeller disc?
The area in which the propeller rotates?
Whats the dome of a propeller called?
Spinner
Most propellers have approximately blank rpm.
1000
What is the component parallel to the rotational axis on a propeller aircraft?
Thrust.
• To preserve the same angle of attack along the whole length of the blade, the blade pitch angle must be progressively increased/decreased from root to tip.
Decreased.
In a variable pitches propeller, what angle is course?
Large angle.
In a variable pitches propeller, what angle is fine?
Small angle,
What is variable pitch propeller alpha range?
Flight range.
What is variable pitch propeller beta range?
Ground range
When would you put a propeller in feathered position?
Engine shut down.
When would you use reverse pitch on a variable pitch propeller?
Reverse thrust.
What does feathering do to a propeller?
Reduce drag.
What can you do to the prop leaver to feather the propeller?
Reduce it
When is a propeller on speed?
When propeller torque drag equals engine torque drag.
What is a propeller spinner susceptible to?
Icing,
What is a propeller driven by?
Engine torque (RPM)
What opposes engine torque on a propeller?
Torque drag.
The propeller is driven by Engine
Torque (RPM)
• Opposing this is Torque drag which
changes in magnitude with blade angle
• These forces are detected and balanced by the blank?
Constant speed unit.
The centrifugal twisting moment in a propeller have a tendency to cause the blade to blank off.
Fine.
An aerodynamic twisting moment atempts to blank off the propeller.
Course.
When would propeller windmilling occur?
When the engine has failed.
What controls the oil in a double Acting Variable Pitch Propeller?
Control speed unit.
In a twin engined aircraft, what position does the spring want to move the propeller (Single Acting Variable Pitch Propeller)
Feathering.
In a single engined aircraft, what position does the spring want to move the propeller (Single Acting Variable Pitch Propeller)
Fine.
The centrifugal latch prevents the blades entering a
Blank condition during engine shut down under
normal operations on a propeller aircraft.
Feathered.
As the csu moves up and the governor weights go out, what happens to the pitch of the propeller fins?
Coarser.
CSU on Speed
•When propeller torque and engine
output are exactly matched the landed
valve shuts off the supply of high-
pressure blank into the valve chamber
• This creates a hydraulic blank which
holds the propeller at the selected
pitch angle.
Oil - Lock
When under speed where do the governor weights move in a csu?
They move in.
What is synchro phased condition on a propeller?
Pressure wave taking turns.
The “slipstream effect” of a propeller is most prominent at… high/low airspeeds with a high/low power setting
Low speed with high power
power lever is moved to the reverse position and the blades move from low pitch ( directly to/via high to )reverse pitch.
Directly to
The main advantage of a constant speed propeller compared to a fixed pitch propeller is that a constant speed propeller…maintains its maximum propeller efficiency over a wider range of blanks.
Airspeeds.
During cruising flight, when the throttle is pulled back on an aeroplane equipped with a constant speed-propeller, the propeller pitch automatically decreases/increases and the RPM increases/decreases/does nothing.
Decreases and does nothing
One of the primary purposes of a propeller reduction gearing system is to…limit the x x x to a value below which efficient operation can be obtained.
Propeller rotation speed.
On an aeroplane equipped with a manual feathering system the pilot can feather the propeller by…pulling the propeller control lever forwards/rearwards.
Rearwards
In the event of an engine failure during flight in a single-engine aeroplane not fitted with a feathering system, the blades of a constant speed propeller tend to move…towards the smallest/biggest blade angle by blank twisting moment and/or spring force.
Smallest - centrifugal
The blade angle of a constant-speed propeller…increases / decreases with true air speed.
Increases
An aircraft is performing a go-around having had a critical engine failure. Which of the following combinations gives the BIGGEST stress on the rudder? Forward/aft CG and 1/2slip/no slip
Aft and no slip
Assuming the RPM and throttle levers are not altered, when TAS increases the blade angle of a constant speed propeller will… increase/decrease?
Increase
A multi-engine piston aircraft both the propellers rotate clockwise as seen from the cockpit. In a go-around, one of the engines fails. Which of the following situations will most probably need the pilot to use full rudder deflection?
Tachometer
A multi-engine piston aircraft both the propellers rotate clockwise as seen from the cockpit. In a go-around, one of the engines fails. Which of the following situations will most probably need the pilot to use full rudder deflection? Left/right failure with a left/right crosswind.
Left
Consider two twin-engine airplanes:
Airplane 1 has clockwise-rotating propellers.
Airplane 2 has inward-rotating propellers.
If, on both airplanes, the left engine fails, which will give the largest yawing moment, and from which side will it be?
Airplane 1 will have the greatest yaw moment, and it will produce a yaw to the left.
For take-off, the correct combination of propeller pitch (high/low), and propeller lever position (forward/aft) for a piston engine at brake release is…
Low / forward
After an engine failure on a twin-engined aircraft, which of the following configurations will put the least strain on the rudder? Forward/aft CG and 1/2slip / no slip towards the OPERATIVE ENGINE.
Forward / 0.5 slip
What direction do you pull the prop for feathering?
Rearwards
One of the primary purposes of a propeller reduction gearing system is to…limit the propeller blank blank to a value below which efficient operation can be obtained.
Rotation speed
