mod 17 mcq june 2010
TRANSCRIPT
MODULE 17 PRACTICE MCQ
http://www.aircrafttechtrng.com
1
Which of the following propeller blades are most affected by fatigue?
Aluminium alloy Wood Composite a
When fitting a propeller to an engine that has a splined shaft
a master spline will determine the correct position
the splines in the hub will fit in any position on the shaft
the front and rear cones must not touch to cause interference
a
When engine power is increased, the constant-speed propeller tries to function so that it will
maintain the RPM, decrease the blade angle
increase the RPM, decrease the blade angle
maintain the RPM, increase the blade angle c
When engine power is increased the constant speed propeller will
maintain RPM by decreasing the blade angle
increase RPM by decreasing the blade angle
maintain the RPM by increasing the blade angle
c
When cleaning an aluminum propeller for inspection, use
mild soap and water steel wool MEK a
When a force is applied to the speeder spring, the blade angle
goes coarser goes finer does not alter b
Variable pitch propellers must be stored in a damp, cool environment to prevent seals drying
dry environment to prevent corrosion
dark environment to prevent oxidation b
Torque acts in opposition to the direction of rotation
in the same direction as the plane of rotation
at right angles to the plane of rotation a
Thrust produced on a propeller is a result of an area of low pressure on
the face of the propeller blades the back of the propeller blades
both surfaces of the propeller blades b
Thrust is generally greatest at 70 to 80% of prop length
equal along the entire length of the prop
greatest in the first 50% of prop length b
The use of a blade station is required when measuring blade angle indexing blades propeller balancing
The thrust face, or side, of a propeller blade is the
rear face or flat side front face or curved side root to which the gear segment is installed a
The synchronisation governor monitors prop tip speeds thrust tip speeds RPM c
The shelf life of a fixed pitch propeller is normally
up to 2 years up to 5 years indefinite c
The shank of the propeller is generally permitted to have
minor repairs no repairs no decals attached b
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2
The purpose of prop twist is to maintain Angle of Attack at the same value along the blade
to maintain Blade Angle along the blade
coarsen the blade angle at the root a
The purpose of blade twist is to reduce the angle of attack at the blade root
even out thrust distribution across the propeller
ensure that tip speed does not go faster than Mach 1
b
The purpose of an arbor used in balancing a propeller is to
support the propeller on the balance knives
level the balance stand mark the propeller blades where weights are to be attached
a
The purpose of an accumulator in a double acting propeller system is to
provide back up to the governor pump
accelerate the un-feathering process
port oil to assist in feathering the propeller b
The propeller tip clearance of a single engine tail wheel aircraft is measured with the aircraft
tail wheel on the ground tail wheel in the take off position
in the rigging position b
The propeller synchronising system is put into operation by
adjusting the engine RPM at required cruise speed then switching on the synchroniser
adjusting the engine RPM then prop RPM to required speed then switching on
switching on the synchroniser then adjust the engine RPM so that all engines adjust together
a
The propeller spinner is used for distributing anti ice fluid propeller balancing decreasing drag c
The propeller governor controls oil to and from the pitch changing mechanism
tension on the internal speeder spring
linkage and counterweight movement
a
The propeller control lever regulates the engine RPM fuel mixture power output a
The propeller blade angle is defined as the acute angle between the airfoil section chord line (at the blade reference station) and the
plane of rotation relative wind propeller thrust line
a
The primary purpose of front and rear cones for propellers that are installed on splined shafts is to
position the hub on the splined shaft
to prevent metal to metal contact between the hub and shaft
to relieve stress in the splines of the shaft a
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3
The primary purpose of a feathering propeller is to
prevent engine damage if it is shut down in flight
prevent propeller damage if the engine is shut down in flight
eliminate drag created by a windmilling propeller of a failed engine
c
The primary purpose of a cuff on a propeller is to distribute anti-ice fluid strengthen the propeller shank
improve the airflow over the blade shank c
The power on a piston engine with a constant-speed propeller is measured by
Manifold Pressure RPM Torque a
The pitch angle of a propeller is the angle between the
propeller reference chord line and the relative airflow
reference chord line and the propeller plane of rotation
propeller reference chord line and the extremity of the propeller
b
The pitch angle of a constant-speed propeller decreases with increasing true air speed
only varies with engine RPM
increases with increasing true air speed c
The output of an anti-icing pump is controlled by a cyclic timer a switch the hand pump b
The optimum angle for a fixed-pitch propeller is 2 - 4 degrees 6 - 10 degrees 15 degrees a
The operational force that tends to increase the blade angle is the
centrifugal twisting force aerodynamic twisting force
thrust bending force b
The operational force that tends to bend the blades forward is the
thrust bending force torque bending force centifugal twisting force a
The operational force that causes the greatest stress on a propeller is the
aerodynamic twisting force centrifugal force thrust bending force b
The operational force that causes the blade tips to lag in the opposite direction to the rotation is the
thrust bending force aerodynamic twisting force
torque bending force c
The main advantage of a constant speed propeller compared to a fixed-pitch propeller is a
higher efficiency in all operating ranges
constant efficiency in all operating ranges
lower propeller blade stress a
The geometric pitch of a propeller is the distance the propeller would move forward in one revolution at the blade angle
angle the propeller chord makes to the plane of rotation
distance the propeller actually moves forward in one revolution a
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4
The gear type pump in a constant speed unit (CSU) or PCU (prop control unit)
lubricates the entire propeller system
boosts engine oil system pressure
assists the governor valve to move b
The function of the automatic propeller synchronising system on a multi-engine aircraft is to control
the blade angle of all propellers.
the engine RPM to reduce vibration.
the power output of each engine to reduce noise.
b
The forces acting on a propeller are centrifugal, twisting, and bending
torsion, tension and thrust
torque, thrust and centrifugal c
The force that turns the blades towards fine pitch is
Torque ATM (aerodynamic twisting moment)
CTM (centrifugal twisting moment) c
The force that tends to decrease the blade angle of a propeller is the
aerodynamic twisting force centrifugal twisting force torque bending force b
The curved surface of a propeller blade is known as the
blade back blade front blade face a
The constant speed unit (CSU) governor works on the principle of
manual selection through a gearbox
centrifugal twisting moments
spring pressure acting against centrifugal force c
The centrifugal latches in a single acting propeller are used to prevent
centrifugal twisting moment (CTM)
feathering of the prop on shutdown
the propeller moving to superfine b
The centrifugal latch is installed to maintain RPM above ground idle
prevent overstress on propeller
prevent propeller feathering on shut down c
The cambered, or curved side of a propeller blade is identified as the blade
back chord leading edge a
The blade angle of a propeller is the angle between the
root chord and the tip chord of the propeller
chord and the airflow relative to the propeller
propeller chord and the plane of rotation of the propeller
c
the blade angle of a constant speed propeller will be greatest during
approach to landing climb high speed, high altitude cruise flight
The blade angle at the root is greater than the tip less than the tip same from tip to root a
The blade angle is constant along the propeller blade
decreases from root to tip
increases from root to tip b
The Beta range of a propeller is from the feather stop to the flight fine pitch stop
feather stop to the ground fine pitch stop
flight fine pitch stop to the reverse pitch stop c
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5
The best method of inspecting an aluminium propeller to detect cracks is the use of
a bright light eddy current dye penetrant c
The angle-of-attack of a rotating propeller blade is measured between the blade chord or face and which of the following?
the plane of blade rotation full low-pitch blade angle the relative airstream
c
The angle of attack of a fixed-pitch propeller depends on
forward speed only forward speed and engine rotational speed
engine rotational speed only b
The angle between the resultant airflow direction and the propeller blade plane of rotation is known as the
angle of attack helix angle or angle of advance
blade angle c
The alpha range of a variable pitch propeller is between
feather and flight fine pitch stop
feather and ground fine pitch stop
flight fine pitch stop and reverse stop a
The alpha range of a variable pitch propeller is between
feather and flight fine pitch stop
feather and ground fine pitch stop
flight fine pitch stop and reverse stop a
The actual distance a propeller moves through the air during one revolution is known as the
effective pitch geometric pitch relative pitch a
The "matrix" in a composite blade is the bonding material reinforcing material foam core a
Synchronisation is used to preset the phase angle of propellers
reduce vibration and noise
reduce the pitch of the fastest running blade b
Stored propellers must be maintained regularly to
replace seals restore them to "zero time since overhaul"
check the torque loadings a
Running an engine with a fixed-pitch propeller at full throttle, with the aircraft stationary and nose into a strong wind will result in
an increase in full throttle rev/min
full throttle rev/min being unaltered
a decrease in full throttle rev/min a
Reverse pitch propellers provide aerodynamic braking reverse the direction of rotation of the propeller
reduce drag a
Removal of material from the propeller blade tips, resulting in a reduction in propeller diameter is called
tipping topping cropping c
Propeller blade stations are measured from the index mark on blade shank hub center line blade tip b
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6
Propellers with adjustable blades can be adjusted
in flight on the ground with the engine running
on the ground with the engine stationary c
Propeller tracking is a procedure for stores acquisition vibration analysis determining blade tip clearance b
Propeller torque is the resistance offered by the propeller to
changing pitch rotation feathering b
Propeller torque is the tendency of the propeller to twist around its longitudinal axis
helical path of the propeller through the air
turning moment produced by the propeller about the axis of the crankshaft
c
Propeller slip rings convey oil for PCU (prop control unit) to pitch change mechanism
minimize Slip conduct electrical power for de icing c
Propeller defects such as nicks and scratches should be repaired promptly to prevent
corrosion unbalanced aerodynamics
fatigue failure c
Propeller blade tracking is the process of determining the
plane of rotation with respect to the aircraft longitudinal axis
blade angles are within the specified tolerance of each other
position of the blade tips relative to each other c
Propeller blade angle increases from root to tip decreases from root to tip
is constant along the blade length b
On a reversing prop moving to the max reversing angle, the prop goes from fine pitch, through plane of
rotation, fine reverse, then coarse reverse
fine pitch, through plane of rotation, coarse reverse, then fine reverse
coarse pitch, through plane of rotation, coarse, reverse, then fine reverse
a
On a piston engine aircraft with a constant speed propeller, the power is set with the
engine RPM and prop RPM manifold pressure and engine RPM gauge
torque and prop RPM gauge b
On a free turbine engine it is possible to vary the propeller RPM while the engine RPM remains constant by operating the
PCU (prop control unit) control lever
power lever reduction gearbox gear lever a
Oil pressure for propeller pitch actuation is provided by
the engine lubrication pump a variable displacement pump
a pump in the governor c
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7
Most engine-propeller combinations have a critical range where continuous operation is not permitted, because it may cause
severe propeller vibration low to negative thrust conditions
inefficiency due to low pitch angles a
Minor transverse cracks on an alloy blade are not repairable may be dressed out with a combination of files
will be removed at overhaul a
Minor repairs to composite propellers may be carried out by
the operator any part 145 maintenance organization
any approved composite repair facility c
In the governor of a constant speed propeller, the pilot valve is activated by
engine oil pressure governor flyweights governor oil pressure b
In the event of an engine failure during flight, the blades of a constant speed propeller in a single engine airplane, not equipped with a feathering system, will move to
the lowest pitch position by centrifugal force
low pitch position by oil pressure created by the windmilling propeller
a predetermined pitch position depending on windmilling RPM
a
If pressure is increased on the speeder springs, the RPM increases and the blade angle
increases decreases remains unchanged b
If a blade of a metal propeller is shortened because of damage, repair to the tip of the remaining blade(s) must be
reset in blade angle to compensate
returned to manufacturer to be matched
shortened to conform with the shortened blade c
Ice is removed from propeller blades by boots that are heated in sequence through the action of a timer
a continuously heated electrical boot
rubber boots inflated in sequence using compressor hot air
a
High speed airfoils are employed at the tips the master station the root a
Ground adjustable propellers allow the propeller blade pitch angles to be set on the ground
the pilot to select only one pitch angle on the ground for local conditions
one adjustment only and cannot be changed
a
Geometric pitch of a propeller is the effective pitch minus slippage effective pitch plus slippage
angle between the blade chord and the airflow b
Geometric Pitch is the distance the propeller moves in one revolution
without slip when slip is maximum with the optimal pich setting a
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8
For takeoff, a constant-speed propeller is normally set in the
high pitch, high RPM position low pitch, low RPM position
low pitch, high RPM position c
For take off, a constant speed propeller is set in the
high pitch high RPM position high pitch low RPM position
low pitch high RPM position c
Fluid and electrical de-icing equipment.
Effective pitch is geometric pitch minus slip distance moved in one revolution
pitch measured at the master station a
Dynamic balance is confirmed by use of knife edges and mandrel a tracking check a vibration analyzer c
During the take-off run, a fixed-pitch propeller is at
too coarse an angle for maximum efficiency
too fine an angle for maximum efficiency
the optimum angle for efficiency a
During take-off an increase in RPM at fixed throttle setting is caused by
the engine over-speeding a more efficient angle of attack of the blades
the propeller blades slipping b
De-icing of the propeller can be monitored by viewing the blade and observing ice falling off
an ammeter in the flight deck
viewing the de-icing boot pulsing action b
Counterweights on constant-speed propellers are generally used to aid in
increasing blade angle decreasing blade angle unfeathering the propellers a
Composite blades are protected against electro-static build up by
braided tapes in the core metal strips in the envelope
using carbon fibre spars b
Coarse pitch is used for take off and climb maximum economical cruise in level flight
landing and power checks b
Centrifugal twisting moment (CTM) in a propeller is a force that
acts at right angles to the plane of rotation of a propeller
twists the blade to fine twists the blade to coarse b
Centrifugal twisting moment (CTM) changes the pitch of a blade
about it’s twisting axis towards the feather plane
bending forward a
Blade station numbers increase from hub to tip tip to hub leading edge to trailing edge a
Blade cuffs are installed to the root of the blades to increase
thrust the strength of the blade flow of air around the blade shank c
Blade angle is taken from the chord and relative airflow propeller shaft plane of rotation c
Blade angle is measured using a bevel protractor propeller protractor clinometer b
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9
As a safety precaution when tracking the propeller, it is advisable the engineer
removes the spark plugs stands well out of the arc of the blades
chocks the aircraft wheels a
As a propeller moves from fine pitch to feather, it passes through
reverse flight fine only coarse c
Anti icing fluid is fed to individual propeller blades by
a pump to each blade rubber feed boot
a pump to a slinger ring gravity to the slinger ring then on to the blade b
Aircraft electrical power for propeller de-icer systems is transferred from the engine to the propeller hub assembly by
slip-rings and segment plates slip-rings and brushes flexible electrical connectors b
Aerodynamic Thrust imbalance can be corrected by
correcting pitch setting static balancing blade tracking a
A vibration caused by a problem with the propeller installation, would have a vibrating frequency that is
higher than turbine vibration the same as turbine vibration
lower than turbine vibration c
A typical propeller governor has the following components
oil pump and cooler speeder spring and diaphragm
speeder spring and fly weights c
A turbo -prop aircraft, reverse thrust is obtained by pulling back the
power lever propeller speed lever condition lever a
A three piece spinner assembly consists of a dome, a
backplate and forward plate back bulkhead and forward bulkhead
backplate and forward bulkhead c
A right hand propeller rotates in a clockwise direction when viewed from the rear
cannot be installed on a left hand engine
rotates in an anti-clockwise direction when viewed from the rear
a
A propeller system BETA range is used to produce zero or negative thrust
is used to produce maximum thrust for take-off
refers to the most fuel efficient pitch range to use at a given RPM
a
A propeller is centralized on the propeller shaft by the
front dirt seal rear pre-load shims front and rear cones c
A propeller control unit (PCU) hydraulic system is supplied with oil from the
aircraft hydraulic system PCU (prop control unit) oil tank
engine lubrication system c
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10
A propeller blade is twisted, so as to keep the local angle of attack constant along the blade
avoid the appearance of sonic phenomena
decrease the blade tangential velocity from the blade root to the tip
a
"Scurfing" a propeller blade is the process carried out to
re-profile the blade tips remove surface cracks prepare the surface for anodising b
"Resonant vibration" generally affects wooden blades aluminium alloy blades composite blades b
"Blending" of propeller blade defects refers to the
repainting of blade tips after cropping
corrosion prevention process of the repair
conversion of rough or sharp edges into smooth depressions
c
Aerodynamic twisting moment tends to turn the blades to a high angle of attack
bend the blades forward turn the blades to low angle of attack a
When un-feathering a propeller, to prevent overspeed, the blades should be put into
coarse pitch fine pitch negative pitch a
When tracking a propeller, it is rotated at idle RPM by hand at cruise RPM b
When the centrifugal force on the fly weights overcomes the tension of the speeder spring, the governor is
on speed underspeed overspeed c
When the fly weights fly outwards in a PCU (prop control unit), this is known as
on-speed under-speed over-speed c
When running up an aircraft into wind, the static RPM will
increase with an increase in wind speed
decrease with an increase in wind speed
remain constant with any wind speed a
When re-installing a propeller, the dynamic balance is maintained by
aligning index marks on the spinner
the location of the dowl pins
torqueing in the correct sequence a
When operating a constant speed propeller, it is usually preferable to have a
high manifold pressure and low engine RPM
high engine RPM and low manifold pressure
balanced prop and engine RPM b
When manufacturing aluminum blades, the final profile of the blade is obtained by
chemical etching milling machine, cutting the airfoil shape
twisting the blade c
When increasing true airspeed with a constant engine RPM, the angle of attack of a fixed-pitch propeller
stays constant increases reduces c
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11
When in reverse pitch, centrifugal twisting moment (CTM) tends to move the propeller blades towards a
negative pitch positive pitch position depending on RPM b
Prior to using a universal propeller protractor check the date stamp for serviceability
determine the reference blade station
ensure the propeller blade is at the horizontal position
b
Operation of electric de-icing boots on individual propeller blades may best be determined by
feeling the boots to see if they are heating
observing the ammeter or load meter for current flow
checking the resistance of each slip ring a
One advantage of a wooden propeller is wood allows more efficient blade construction
does not have a fatigue life
is more cost effective b
On an engine which is operating in the constant speed range, moving the throttle further to the open position will
increase the blade angle increase the RPM have no effect on the blade angle a
On a spinner assembly, the index marks are used to align the
backplate and forward bulkhead with the spinner dome
hub and propeller assembly
hub and spinner dome a
On a scheduled servicing, a propeller spinner would normally be checked for
balance cracks correct lubrication b
In an ‘on speed’ condition of a constant speed unit, (CSU), oil flows
to the propeller from the propeller to the engine c
In a propeller with counterweights, the force used to move the propeller to fine pitch is the
aerodynamic twisting moment (ATM)
centrifugal force acting on the counterweights
governor oil pressure c
If the tension on the speeder spring is increased in the governor, the blade angle will
increase and RPM will decrease
decrease and RPM will decrease
decrease and RPM will increase c
If the speeder spring pressure of a constant speed unit (CSU) is increased the blade will
fine off coarsen off not move a
Synchronisation is used in flight at all times in flight except landing and take off
whenever the engine is running b
If the RPM and manifold pressure (MAP) levers are not moved and the true air speed (TAS) increases, the pitch angle of a constant speed propeller
first reduces and after a short time increases to its previous value
reduces increases
c
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12
If the governor fly wheel overcomes the speeder spring, it indicates
over-speed under-speed on-speed a
If the blade angle is increased the pitch becomes finer. the pitch becomes coarser
lateral stability decreases. b