Turboprop Engines
Based on the criteria of efficiency of an
engines weight to the power it produces,
which type of engine is the best choice for
an aircraft operating at speeds of 300mph at
altitudes between 20,000-25,000 ft?
its firing order is 1-3-5-7-9-2-4-6-8
An aircraft engine has 9 cylinders. From this
information alone we can deduce that
The crankcase of an aircraft engine Is the foundation of the engine containing crankshaft bearings and cylinder pads
by studs mounted in threaded holes in the crankcase
The cylinders of an engine are mounted on
cylinder pads that are machined onto the
crankcases. The common method of
attachment of the cylinders to the crankcase
is
The crankpin is Hardened by nitriding and is hollow to reduce weight
Which statement is correct about radial Moveable counterweights serve to reduce the dynamic vibrations in an aircraft
engine aircraft? reciprocating engine.
Master rod bearings are generally what Plain
type?
provide a better fit at operating temperatures
Cam-ground pistons are installed in some
aircraft engines to
Full-floating piston pins are those which the piston and the small end of the connecting rod.
allow motion between the pin and
How is the oil collected by the piston oil ring Through holes drilled in the piston oil ring grooves
returned to the crankcase?
An initial precision fit.
Which is the primary factor in ensuring a gas
tight joint between a cylinder barrel and the
cylinder head?
opposed cylinders from the rear to the front.
Which is the typical firing order on a 4
cylinder opposed aircraft engine?
reduced valve operating temperatures.
What is the advantage of using sodium filled
exhaust valves in aircraft reciprocating
engines?
What is the purpose of the stem keys To hold the valve spring retaining washer in position.
installed on the valve stems?
To eliminate valve spring vibration or surging.
What is the purpose of installing two or more
springs on each valve in an aircraft engine?
Radial engine.
Cam roller, cam rings, and cam tracks are a
part of the valve operating mechanisms of
which engine type?
decreases valve overlap
Excessive valve clearance in a piston engine
replacing the pushrod
valve clearance changes on opposed-type
engines using hydraulic lifters are
accomplished by
, Deep-grooved ball
Which of the following is a characteristic of a
thrust bearing used in most radial engines?
What is the primary advantage of using To enable the engine RPM to increase with an accompanying increase in power and
propeller reduction gears? allow the propeller shaft to remain at a lower rpm.
Number 1 @ TDC
On a smaller aircraft engine with a keyed
propeller shaft, to what is the keyway
aligned with during installation of the
propeller?
both closed
During the power stroke of a 4-stroke
engine, which are correct positions of the
valves?
On which stroke are both valves on a four- Intake and exhaust
stroke cycle reciprocating engine open?
Just after TDC at the beginning of the power stroke.
If fuel/air ratio is proper and ignition timing is
correct, the combustion process should be
completed
Brake HP
The actual power delivered to the propeller
of an aircraft engine is called
The compression ratio of an engine is equal The volume of the cylinder with the piston at BDC divided by the volume of the cylinder
at TDC
to
The intake valve closes.
During a 4 stroke cycle, which of the
following event occurs at about 60 degrees
after BTC
3
How many of the following are factors in
establishing the maximum compression ratio
limitations of an aircraft engine?
Indicated HP
The HP developed in the cylinders of a
reciprocating engine is known as the
Friction HP May be as high as 10-15% of the indicated HP on a modern aircraft engine.
Indicated HP
What is defined by the equation: _______ =
PLANK/33,000
The thermal efficiency of an engine Affects the fuel consumption of an engine
3. Improper valve timing
Which of the following will decrease 4. Sharp bends in the induction system
volumetric efficiency in a reciprocating 5. high carburetor air temperatures
engine?
Propulsive efficiency is maximized through the use of a constant-speed prop
Turbofan engines
Most modern airliners that fly in the .8 mach
speed range are fitted with
Driven at reduced speed from the high pressure compressor via a reduction gear box
Accessories such as electric generators and
hydraulic pumps on turbine powered aircraft
are...
supply air in sufficient quantity for combustion
The primary function of the compressor on a
gas turbine engine is to?
A compressor with vanes on both sides of the impeller
What is meant by a double entry centrifugal
compressor?
, increase air pressure.
What is the primary purpose of stator vanes
in the compressor of an axial flow turbine
engine?
What is the function of the inlet guide vane Directs air onto the first stage rotor blades at the proper angle.
assembly on an axial-flow compressor?
Diffuser
Which component of a centrifugal flow
compressor performs the most similar work
as does the rear stator vanes in an axial flow
compressor?
Number of compressor stages
The compression ratio of an axial flow
compressor is a function of the
What is referred to as blade profile of a A cutout that reduces blade tip thickness
turbine engine compressor blade?
Greater pressure ratio
What is the primary advantage of an axial
flow compressor over a centrifugal flow
compressor?
N2 compressor
In the dual axial-flow or twin spool
compressor system, the first stage turbine
drives the
What is the purpose of the diffuser section of To increase air pressure and decrease its velocity
a turbine engine?
What turbine engine section provides for Combustion section
proper mixing of fuel and air?
Used to support combustion and to cool the engine
The air passing through the combustion
chamber of a turbine engine is
Turbine inlet nozzle vanes
The highest heat to metal contacts in a jet
engine are the
Exposure to high operating temperatures
Why are turbine blades generally more
susceptible to operating damage than
compressor blades?
The function of an exhaust cone assembly of Straighten and collect the exhaust gases into a solid exhaust jet
a turbine engine is to
Provide and oil film between the outer race and the bearing housing in order to reduce
The oil dampened also known as hydraulic vibration tendencies in the rotor system and to allow for slight misalignment
main bearing utilized in some turbine
engines is used to
Labyrinth and/or carbon rubbing
Mean bearing oil seals used in turbine
engines are usually what type?
Additional turbine stages
The energy to turn the propeller on a
turboprop engine is typically produced by
Based on the criteria of efficiency of an
engines weight to the power it produces,
which type of engine is the best choice for
an aircraft operating at speeds of 300mph at
altitudes between 20,000-25,000 ft?
its firing order is 1-3-5-7-9-2-4-6-8
An aircraft engine has 9 cylinders. From this
information alone we can deduce that
The crankcase of an aircraft engine Is the foundation of the engine containing crankshaft bearings and cylinder pads
by studs mounted in threaded holes in the crankcase
The cylinders of an engine are mounted on
cylinder pads that are machined onto the
crankcases. The common method of
attachment of the cylinders to the crankcase
is
The crankpin is Hardened by nitriding and is hollow to reduce weight
Which statement is correct about radial Moveable counterweights serve to reduce the dynamic vibrations in an aircraft
engine aircraft? reciprocating engine.
Master rod bearings are generally what Plain
type?
provide a better fit at operating temperatures
Cam-ground pistons are installed in some
aircraft engines to
Full-floating piston pins are those which the piston and the small end of the connecting rod.
allow motion between the pin and
How is the oil collected by the piston oil ring Through holes drilled in the piston oil ring grooves
returned to the crankcase?
An initial precision fit.
Which is the primary factor in ensuring a gas
tight joint between a cylinder barrel and the
cylinder head?
opposed cylinders from the rear to the front.
Which is the typical firing order on a 4
cylinder opposed aircraft engine?
reduced valve operating temperatures.
What is the advantage of using sodium filled
exhaust valves in aircraft reciprocating
engines?
What is the purpose of the stem keys To hold the valve spring retaining washer in position.
installed on the valve stems?
To eliminate valve spring vibration or surging.
What is the purpose of installing two or more
springs on each valve in an aircraft engine?
Radial engine.
Cam roller, cam rings, and cam tracks are a
part of the valve operating mechanisms of
which engine type?
decreases valve overlap
Excessive valve clearance in a piston engine
replacing the pushrod
valve clearance changes on opposed-type
engines using hydraulic lifters are
accomplished by
, Deep-grooved ball
Which of the following is a characteristic of a
thrust bearing used in most radial engines?
What is the primary advantage of using To enable the engine RPM to increase with an accompanying increase in power and
propeller reduction gears? allow the propeller shaft to remain at a lower rpm.
Number 1 @ TDC
On a smaller aircraft engine with a keyed
propeller shaft, to what is the keyway
aligned with during installation of the
propeller?
both closed
During the power stroke of a 4-stroke
engine, which are correct positions of the
valves?
On which stroke are both valves on a four- Intake and exhaust
stroke cycle reciprocating engine open?
Just after TDC at the beginning of the power stroke.
If fuel/air ratio is proper and ignition timing is
correct, the combustion process should be
completed
Brake HP
The actual power delivered to the propeller
of an aircraft engine is called
The compression ratio of an engine is equal The volume of the cylinder with the piston at BDC divided by the volume of the cylinder
at TDC
to
The intake valve closes.
During a 4 stroke cycle, which of the
following event occurs at about 60 degrees
after BTC
3
How many of the following are factors in
establishing the maximum compression ratio
limitations of an aircraft engine?
Indicated HP
The HP developed in the cylinders of a
reciprocating engine is known as the
Friction HP May be as high as 10-15% of the indicated HP on a modern aircraft engine.
Indicated HP
What is defined by the equation: _______ =
PLANK/33,000
The thermal efficiency of an engine Affects the fuel consumption of an engine
3. Improper valve timing
Which of the following will decrease 4. Sharp bends in the induction system
volumetric efficiency in a reciprocating 5. high carburetor air temperatures
engine?
Propulsive efficiency is maximized through the use of a constant-speed prop
Turbofan engines
Most modern airliners that fly in the .8 mach
speed range are fitted with
Driven at reduced speed from the high pressure compressor via a reduction gear box
Accessories such as electric generators and
hydraulic pumps on turbine powered aircraft
are...
supply air in sufficient quantity for combustion
The primary function of the compressor on a
gas turbine engine is to?
A compressor with vanes on both sides of the impeller
What is meant by a double entry centrifugal
compressor?
, increase air pressure.
What is the primary purpose of stator vanes
in the compressor of an axial flow turbine
engine?
What is the function of the inlet guide vane Directs air onto the first stage rotor blades at the proper angle.
assembly on an axial-flow compressor?
Diffuser
Which component of a centrifugal flow
compressor performs the most similar work
as does the rear stator vanes in an axial flow
compressor?
Number of compressor stages
The compression ratio of an axial flow
compressor is a function of the
What is referred to as blade profile of a A cutout that reduces blade tip thickness
turbine engine compressor blade?
Greater pressure ratio
What is the primary advantage of an axial
flow compressor over a centrifugal flow
compressor?
N2 compressor
In the dual axial-flow or twin spool
compressor system, the first stage turbine
drives the
What is the purpose of the diffuser section of To increase air pressure and decrease its velocity
a turbine engine?
What turbine engine section provides for Combustion section
proper mixing of fuel and air?
Used to support combustion and to cool the engine
The air passing through the combustion
chamber of a turbine engine is
Turbine inlet nozzle vanes
The highest heat to metal contacts in a jet
engine are the
Exposure to high operating temperatures
Why are turbine blades generally more
susceptible to operating damage than
compressor blades?
The function of an exhaust cone assembly of Straighten and collect the exhaust gases into a solid exhaust jet
a turbine engine is to
Provide and oil film between the outer race and the bearing housing in order to reduce
The oil dampened also known as hydraulic vibration tendencies in the rotor system and to allow for slight misalignment
main bearing utilized in some turbine
engines is used to
Labyrinth and/or carbon rubbing
Mean bearing oil seals used in turbine
engines are usually what type?
Additional turbine stages
The energy to turn the propeller on a
turboprop engine is typically produced by
