Powerplant Oral ASA
Study online at https://quizlet.com/_he7jzf
1. What is the main advantage of a horizontally op- smaller frontal area and easi-
posed engine over a radial engine for powering er to streamline.
modern aircraft?
2. How many throws are there in the crankshaft of a six
six-cylinder horizontally opposed engine?
3. What kind of connecting rod arrangement is used in a master rod connects the
a radial engine? single throw of the crankshaft
with a piston. all other pistons
are connected to the master
rod with link rods
4. Of what material are most piston rings made? grey cast iron
5. What is the reason for using hydraulic valve lifters in keep all of the clearance out
an aircraft engine? of the valve operating mecha-
nism, decreases wear of valve
train components
6. At what speed does the camshaft turn, relative to camshaft is one half the
the crankshaft speed in a horizontally opposed en- speed of crankshaft
gine?
7. What kind of main bearings are used in a horizon- steel backed lead alloy bear-
tally opposed engine? ings
8. On what stroke is the piston of a reciprocating en- exhaust
gine when the intake valve begins to open?
9. On what stroke is the piston of a reciprocating en- power
gine when the exhaust valve begins to open?
10.
, Powerplant Oral ASA
Study online at https://quizlet.com/_he7jzf
Why are both the hot and cold valve clearances hot clearance is for valve
given for most radial engines? timing. timing adjusted with
valves in cylinder 1 set with
hot clearance then adjusted
to cold clearance
11. What is meant by a cam-ground piston A piston that is not perfect-
ly round. . When the pis-
ton reaches operating tem-
perature, the metal expands
enough that the piston be-
comes perfectly round.
12. Where is the piston in a reciprocating engine when before top dead center on the
the ignition spark occurs? compression stroke
13. What is meant by a full-floating wrist pin? pin not clamped in either pis-
ton or connecting rod
14. Why do most aircraft reciprocating engines use for different frequen-
more than one spring on each valve? cies/rpms
15. Would excessive valve clearance cause the valves to open late close early
open early or late?
16. What is the purpose of valve overlap in a reciprocat- Valve overlap allows the iner-
ing engine? tia of the exhaust gases leav-
ing the cylinder to help the
fresh induction charge start
flowing into the cylinder.
17. What type of piston rings are installed on the pis- compression, oil control, oil
tons of an aircraft reciprocating engine? wiper
, Powerplant Oral ASA
Study online at https://quizlet.com/_he7jzf
18. Why are some exhaust valves partially filled with The metallic sodium melts at
metallic sodium? engine operating tempera-
ture 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
19. What causes detonation in an aircraft engine? Excessive heat and pressure
in the engine cylinder , the
mixture explodes rather than
burns.
20. Why is a compression check important for deter- to check condition of seals
mining the condition of an aircraft reciprocating en- between piston ring and
gine? cylinder wall and valves and
thier seats
21. What is meant by the compression ratio of a recip- ratio of volume of cylinder
rocating engine? with piston at bottom vs pis-
ton at top
22. What are the two basic sections of a turbine engine? hot and cold
23. What are the two basic types of compressors that axial flow and centrifugal
are used in aircraft turbine engines?
24. What is the purpose of the stators in an axial-flow convert velocity energy to
compressor? pressure energy and change
direction of air
25. What are three types of combustors used on aircraft can, annular, can-annular
turbine engines?
, Powerplant Oral ASA
Study online at https://quizlet.com/_he7jzf
26. How many igniters are there normally in an aircraft two
turbine engine?
27. What is the main purpose of the turbine nozzle in an direct gasses as they leave
aircraft turbine engine? combustors so they will turn
turbine wheel with maximum
efficiency
28. What is meant by a free-turbine turboshaft engine A turboshaft engine that has
a turbine wheel, that is not
used to drive the compres-
sor of the gas generator sec-
tion of the engine. This free
turbine drives the propeller
in a turboprop engine or the
transmission and rotor of a
helicopter.
29. Why do some axial-flow turbine engines have more A two-spool turbine en-
than one set of turbines and compressors gine has a low-pressure and
a high-pressure compressor,
each driven by its own tur-
bine. The two independent
systems operate at the speed
at which they are most effi-
cient.
30. What kind of bearings are used to support the rotor anti fiction, ball, roller
shaft of an aircraft turbine engine
31. What is meant by a turbofan engine An axial-flow turbine en-
gine in which the first stage
of compressor blades are
Study online at https://quizlet.com/_he7jzf
1. What is the main advantage of a horizontally op- smaller frontal area and easi-
posed engine over a radial engine for powering er to streamline.
modern aircraft?
2. How many throws are there in the crankshaft of a six
six-cylinder horizontally opposed engine?
3. What kind of connecting rod arrangement is used in a master rod connects the
a radial engine? single throw of the crankshaft
with a piston. all other pistons
are connected to the master
rod with link rods
4. Of what material are most piston rings made? grey cast iron
5. What is the reason for using hydraulic valve lifters in keep all of the clearance out
an aircraft engine? of the valve operating mecha-
nism, decreases wear of valve
train components
6. At what speed does the camshaft turn, relative to camshaft is one half the
the crankshaft speed in a horizontally opposed en- speed of crankshaft
gine?
7. What kind of main bearings are used in a horizon- steel backed lead alloy bear-
tally opposed engine? ings
8. On what stroke is the piston of a reciprocating en- exhaust
gine when the intake valve begins to open?
9. On what stroke is the piston of a reciprocating en- power
gine when the exhaust valve begins to open?
10.
, Powerplant Oral ASA
Study online at https://quizlet.com/_he7jzf
Why are both the hot and cold valve clearances hot clearance is for valve
given for most radial engines? timing. timing adjusted with
valves in cylinder 1 set with
hot clearance then adjusted
to cold clearance
11. What is meant by a cam-ground piston A piston that is not perfect-
ly round. . When the pis-
ton reaches operating tem-
perature, the metal expands
enough that the piston be-
comes perfectly round.
12. Where is the piston in a reciprocating engine when before top dead center on the
the ignition spark occurs? compression stroke
13. What is meant by a full-floating wrist pin? pin not clamped in either pis-
ton or connecting rod
14. Why do most aircraft reciprocating engines use for different frequen-
more than one spring on each valve? cies/rpms
15. Would excessive valve clearance cause the valves to open late close early
open early or late?
16. What is the purpose of valve overlap in a reciprocat- Valve overlap allows the iner-
ing engine? tia of the exhaust gases leav-
ing the cylinder to help the
fresh induction charge start
flowing into the cylinder.
17. What type of piston rings are installed on the pis- compression, oil control, oil
tons of an aircraft reciprocating engine? wiper
, Powerplant Oral ASA
Study online at https://quizlet.com/_he7jzf
18. Why are some exhaust valves partially filled with The metallic sodium melts at
metallic sodium? engine operating tempera-
ture 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
19. What causes detonation in an aircraft engine? Excessive heat and pressure
in the engine cylinder , the
mixture explodes rather than
burns.
20. Why is a compression check important for deter- to check condition of seals
mining the condition of an aircraft reciprocating en- between piston ring and
gine? cylinder wall and valves and
thier seats
21. What is meant by the compression ratio of a recip- ratio of volume of cylinder
rocating engine? with piston at bottom vs pis-
ton at top
22. What are the two basic sections of a turbine engine? hot and cold
23. What are the two basic types of compressors that axial flow and centrifugal
are used in aircraft turbine engines?
24. What is the purpose of the stators in an axial-flow convert velocity energy to
compressor? pressure energy and change
direction of air
25. What are three types of combustors used on aircraft can, annular, can-annular
turbine engines?
, Powerplant Oral ASA
Study online at https://quizlet.com/_he7jzf
26. How many igniters are there normally in an aircraft two
turbine engine?
27. What is the main purpose of the turbine nozzle in an direct gasses as they leave
aircraft turbine engine? combustors so they will turn
turbine wheel with maximum
efficiency
28. What is meant by a free-turbine turboshaft engine A turboshaft engine that has
a turbine wheel, that is not
used to drive the compres-
sor of the gas generator sec-
tion of the engine. This free
turbine drives the propeller
in a turboprop engine or the
transmission and rotor of a
helicopter.
29. Why do some axial-flow turbine engines have more A two-spool turbine en-
than one set of turbines and compressors gine has a low-pressure and
a high-pressure compressor,
each driven by its own tur-
bine. The two independent
systems operate at the speed
at which they are most effi-
cient.
30. What kind of bearings are used to support the rotor anti fiction, ball, roller
shaft of an aircraft turbine engine
31. What is meant by a turbofan engine An axial-flow turbine en-
gine in which the first stage
of compressor blades are
