ASA POWERPLANT ORAL EXAM 2 LATEST
VERSIONS ACTUAL EXAM COMPLETE 400
QUESTIONS AND CORRECT DETAILED ANSWERS
|ALREADY GRADED A+
What are two locations water may be injected into a turbine engine?
- ANS-At the compressor inlet and at the inlet to the diffuser
section.
What is meant by a duplex nozzle in a turbine engine fuel metering
system? - ANS-one that has two fuel discharge passages
What is the function of a float carburetor? - ANS-The float
carburetor's function is to measure airflow through the engine
induction system and measure out the appropriate amount of
gasoline into the air for all engine operating perimeters and
conditions. It must also provide the fuel in as complete a vaporized
state as possible by the time ignition occurs in the engine cylinders.
Does the fuel-air mixture provided by a float carburetor become
richer or leaner as the aircraft goes up in altitude? - ANS-richer if it is
not adjusted
Does the fuel-air mixture provided by a float carburetor become
richer or leaner when carburetor heat is applied? - ANS-richer
What would happen to the fuel-air mixture ratio in a float carburetor
if the main air bleed were to become plugged? - ANS-mix would be
excessively rich
How does the automatic mixture control in a pressure carburetor
keep the fuel-air mixture constant as the aircraft changes altitude? -
,ANS-It automatically, and progressively, bleeds the air between the
two sides of the air diaphragm and decreases the air metering force.
This leans the mixture as the aircraft goes up in altitude.
What are two purposes of the manifold valve (or flow divider) in the
fuel injection system of a horizontally opposed aircraft engine? -
ANS-It provides a constant discharge fuel pressure for idling, and it
provides a positive shutoff for the fuel when the engine is shut down
What is the main advantage of a horizontally opposed engine over a
radial engine for powering modern aircraft? - ANS-smaller frontal
area and easier to streamline.
How many throws are there in the crankshaft of a six-cylinder
horizontally opposed engine? - ANS-six
What kind of connecting rod arrangement is used in a radial engine?
- ANS-a master rod connects the single throw of the crankshaft with
a piston. all other pistons are connected to the master rod with link
rods
Of what material are most piston rings made? - ANS-grey cast iron
What is the reason for using hydraulic valve lifters in an aircraft
engine? - ANS-keep all of the clearance out of the valve operating
mechanism, decreases wear of valve train components
At what speed does the camshaft turn, relative to the crankshaft
speed in a horizontally opposed engine? - ANS-camshaft is one half
the speed of crankshaft
,What kind of main bearings are used in a horizontally opposed
engine? - ANS-steel backed lead alloy bearings
On what stroke is the piston of a reciprocating engine when the
intake valve begins to open? - ANS-exhaust
On what stroke is the piston of a reciprocating engine when the
exhaust valve begins to open? - ANS-power
Why are both the hot and cold valve clearances given for most radial
engines? - ANS-hot clearance is for valve timing. timing adjusted
with valves in cylinder 1 set with hot clearance then adjusted to cold
clearance
What is meant by a cam-ground piston - ANS-A piston that is not
perfectly round. . When the piston reaches operating temperature,
the metal expands enough that the piston becomes perfectly round.
Where is the piston in a reciprocating engine when the ignition spark
occurs? - ANS-before top dead center on the compression stroke
What is meant by a full-floating wrist pin? - ANS-pin not clamped in
either piston or connecting rod
Why do most aircraft reciprocating engines use more than one
spring on each valve? - ANS-for different frequencies/rpms
Would excessive valve clearance cause the valves to open early or
late? - ANS-open late close early
What is the purpose of valve overlap in a reciprocating engine? -
ANS-Valve overlap allows the inertia of the exhaust gases leaving
, the cylinder to help the fresh induction charge start flowing into the
cylinder.
What type of piston rings are installed on the pistons of an aircraft
reciprocating engine? - ANS-compression, oil control, oil wiper
Why are some exhaust valves partially filled with metallic sodium? -
ANS-The metallic sodium melts at engine operating temperature It
picks up heat from the valve head and transfers it into the valve
stem, so it can be transferred to the cylinder head through the valve
guide
What causes detonation in an aircraft engine? - ANS-Excessive heat
and pressure in the engine cylinder , the mixture explodes rather
than burns.
Why is a compression check important for determining the
condition of an aircraft reciprocating engine? - ANS-to check
condition of seals between piston ring and cylinder wall and valves
and thier seats
What is meant by the compression ratio of a reciprocating engine? -
ANS-ratio of volume of cylinder with piston at bottom vs piston at
top
What are the two basic sections of a turbine engine? - ANS-hot and
cold
What are the two basic types of compressors that are used in
aircraft turbine engines? - ANS-axial flow and centrifugal
VERSIONS ACTUAL EXAM COMPLETE 400
QUESTIONS AND CORRECT DETAILED ANSWERS
|ALREADY GRADED A+
What are two locations water may be injected into a turbine engine?
- ANS-At the compressor inlet and at the inlet to the diffuser
section.
What is meant by a duplex nozzle in a turbine engine fuel metering
system? - ANS-one that has two fuel discharge passages
What is the function of a float carburetor? - ANS-The float
carburetor's function is to measure airflow through the engine
induction system and measure out the appropriate amount of
gasoline into the air for all engine operating perimeters and
conditions. It must also provide the fuel in as complete a vaporized
state as possible by the time ignition occurs in the engine cylinders.
Does the fuel-air mixture provided by a float carburetor become
richer or leaner as the aircraft goes up in altitude? - ANS-richer if it is
not adjusted
Does the fuel-air mixture provided by a float carburetor become
richer or leaner when carburetor heat is applied? - ANS-richer
What would happen to the fuel-air mixture ratio in a float carburetor
if the main air bleed were to become plugged? - ANS-mix would be
excessively rich
How does the automatic mixture control in a pressure carburetor
keep the fuel-air mixture constant as the aircraft changes altitude? -
,ANS-It automatically, and progressively, bleeds the air between the
two sides of the air diaphragm and decreases the air metering force.
This leans the mixture as the aircraft goes up in altitude.
What are two purposes of the manifold valve (or flow divider) in the
fuel injection system of a horizontally opposed aircraft engine? -
ANS-It provides a constant discharge fuel pressure for idling, and it
provides a positive shutoff for the fuel when the engine is shut down
What is the main advantage of a horizontally opposed engine over a
radial engine for powering modern aircraft? - ANS-smaller frontal
area and easier to streamline.
How many throws are there in the crankshaft of a six-cylinder
horizontally opposed engine? - ANS-six
What kind of connecting rod arrangement is used in a radial engine?
- ANS-a master rod connects the single throw of the crankshaft with
a piston. all other pistons are connected to the master rod with link
rods
Of what material are most piston rings made? - ANS-grey cast iron
What is the reason for using hydraulic valve lifters in an aircraft
engine? - ANS-keep all of the clearance out of the valve operating
mechanism, decreases wear of valve train components
At what speed does the camshaft turn, relative to the crankshaft
speed in a horizontally opposed engine? - ANS-camshaft is one half
the speed of crankshaft
,What kind of main bearings are used in a horizontally opposed
engine? - ANS-steel backed lead alloy bearings
On what stroke is the piston of a reciprocating engine when the
intake valve begins to open? - ANS-exhaust
On what stroke is the piston of a reciprocating engine when the
exhaust valve begins to open? - ANS-power
Why are both the hot and cold valve clearances given for most radial
engines? - ANS-hot clearance is for valve timing. timing adjusted
with valves in cylinder 1 set with hot clearance then adjusted to cold
clearance
What is meant by a cam-ground piston - ANS-A piston that is not
perfectly round. . When the piston reaches operating temperature,
the metal expands enough that the piston becomes perfectly round.
Where is the piston in a reciprocating engine when the ignition spark
occurs? - ANS-before top dead center on the compression stroke
What is meant by a full-floating wrist pin? - ANS-pin not clamped in
either piston or connecting rod
Why do most aircraft reciprocating engines use more than one
spring on each valve? - ANS-for different frequencies/rpms
Would excessive valve clearance cause the valves to open early or
late? - ANS-open late close early
What is the purpose of valve overlap in a reciprocating engine? -
ANS-Valve overlap allows the inertia of the exhaust gases leaving
, the cylinder to help the fresh induction charge start flowing into the
cylinder.
What type of piston rings are installed on the pistons of an aircraft
reciprocating engine? - ANS-compression, oil control, oil wiper
Why are some exhaust valves partially filled with metallic sodium? -
ANS-The metallic sodium melts at engine operating temperature It
picks up heat from the valve head and transfers it into the valve
stem, so it can be transferred to the cylinder head through the valve
guide
What causes detonation in an aircraft engine? - ANS-Excessive heat
and pressure in the engine cylinder , the mixture explodes rather
than burns.
Why is a compression check important for determining the
condition of an aircraft reciprocating engine? - ANS-to check
condition of seals between piston ring and cylinder wall and valves
and thier seats
What is meant by the compression ratio of a reciprocating engine? -
ANS-ratio of volume of cylinder with piston at bottom vs piston at
top
What are the two basic sections of a turbine engine? - ANS-hot and
cold
What are the two basic types of compressors that are used in
aircraft turbine engines? - ANS-axial flow and centrifugal
