問題一覧
1
At what point in an axial-flow curbojet engine will the highest gas pressures occur?
At the compressor outlet
2
The actual power delivered to the propeller of an aircraft engine is called
brake horsepower
3
On a twin-engine aircraft with fuel-injected reciprocating engines, one fuel-flow indicator reads considerably higher than the other in all engine operating configurations. What is the probable cause of this indication?
One or more fuel nozzle are clogged
4
Which statement is correct regarding a four-stroke cycie aircraft engine?
The intake valve closes on the compression stroke
5
When does valve overlap occur in the operation of aircraft reciprocating engine?
At the end of the exhaust stroke and the beginning of the intake stroke
6
Which of the following bearing types must be continuously lubricated by pressure oil?
Plain
7
Valve clearance changes on opposed-type engines using hy draulic lifters are accomplished by
push rod replacement
8
A manifold pressure gauge is designed to
indicate absolute pressure in the intake manifold
9
Which of the following is most likely to occur if an overhead valve engine is operated with inadequate valve clearances?
The valve will not seat positively during start and engine warm-up
10
A hissing sound from the exhaust stacks when the propeller is being pulled through manually indicates
exhaust valve blow-by
11
You are performing a 100-hour inspection on an R985-22 aircraft engine. What does the 985" indicate?
The total piston displacement of the engine
12
In addition to fuel quantity. a computerized fuel system (CFS) with a totalizer-indicator provides indication of how many of the following? 1. Fuel flow rate 2. Fuel used since reset or initial sart-up. 3. Fuel time remaining at curent power seting. 4. Fuel termperature.
Three
13
Basically, the indicator of a tachometer system is responsive to change in
frequency
14
The fuel flow meter used with a continuous-fuel injection system installed on an aircraft horizontally opposed reciprocating engine measures the fuel pressure drop across the
fuel nozzle
15
What does valve overlap promote?
Better scavenging and cooling characteristics
16
What is the principal advantage of using propeller reduction gears?
To enable the engine RPM to be increased with an accompanying increase in power and allow the propeller to remain at a lower, more efficient RPM.
17
An unsupercharged air oraft reciprocating engine, operated at full throttle from sea level to 10,000 feet, provided the RPM is unchanged, will
lose power due to the reduced density of the air drawn into the cylinders.
18
The principle fault in the pressure type fuel flow meter indicating system, installed on a horizontally opposed continuous-flow fuel injected aircraft reciprocating engine, is that a plugged fuel injection nuzzle will cause a
higher than normal fuel flow indication
19
Increased engine heat wIll cause volumetric efficiency to
decrease
20
Which bearing is least likely to be a roller or ball bearing?
Master rod bearing (radial engine)
21
Which of the following is a characteristic of a thrust bearing used in most radial engines?
Deep-groove ball
22
The operating temperature valve clearance of a radial engine as compared to cold valve clearance is
greater
23
Which statement is true regarding bearings used in high-powered reciprocating aircraft engines?
There is less rolling friction when ball bearings are used than when roller bearings are employed.
24
What basic meter is used to indicate cylinder head temperature in most aircraft?
Galvanometer
25
How are the piston pins of most aircraft engines Iubricated?
By oil which is sprayed or thrown by the master or connecting rods.
26
The norsepower develor 2d in the cylinders of a reciprocating engine is known as the
indicated horsepower
27
If the exhaust valve of a four-stroke cycle engine is closed and the intake valve is just closed, the piston is on the
compression stroke
28
What is the profile of a turbine engine compressor blade?
A cutout that reduces blade tip thickness
29
Some cylinder barrels are hardened by
nitriding
30
If air is heard coming from the crankcase breather or oil filler during a differential compression check, what is this an indication of?
Piston ring leakage
31
On which strokes are both valves on a four-stroke cycle reciprocating engine open?
Exhaust and intake
32
Full-floating piston pins are those which allow motion between the pin and
both the piston and the small end of the connecting rod.
33
Which of the following types of electric motors are commonly used in electric tachometers?
Synchronous motors
34
The volume of a cylinder equals 70 cubic inches when the piston is at bottom center. When the piston is at the top of the cylinder, the volume equals 10 cubic inches. What is the compression ratio?
7:1
35
If an engine with a stroke of 6 inches is operated at 2,000 RPM, the piston movement within the cylinder will be
at maximum velocity 90° after TDC
36
The fuel-flow indication data sent from motor driven impeller and turbine, and motorless type fuel flow transmitters is a measure of
fuel mass-flow
37
If fuel/air ratio is proper and ignition timing is correct, the combustion process should be completed.
just after top center at the beginning of the power stroke.
38
Which statement is correct concerning a thermocouple-type temperature indicating instrument system?
It requires no external power source
39
Excessive valve clearance results in the valves opening
late and closing early
40
The primary purpose in setting proper valve timing and overlap is to
obtain the best volumetric efficiency and lower cylinder operating temperatures
41
Newton's First Law of Motion, generally tenned the Law of Inertia, states:
Every body persists in its state of rest, or of motion ina straight line, unless acted upon by some outside force.
42
An increase in manifold pressure with a constant RPM will cause the bearing load in an engine to
increase
43
Using the following information, determine how many degrees the crankshaft will rotate with both the intake and exhaust valves seated. Intake opens 15° BTDC. Exhaust opens 70° BBDC. Intake closes 45° ABDC. Exhaust closes 10° ATDC.
245°
44
Excessive valve clearances will cause the duration of valve opening to
decrease for both intake and exhaust valves
45
Compression ratio is the ratio between the
cylinder volume with piston at bottom dead center and at top dead center.
46
Some aircraft engine manufacturers equip their product with choked or taper-ground cylinders in order to
provide a straight cylinder bore at operating temperatures
47
Using standard atmospheric conditions, the standard sea level temnperature is
59°F
48
Which of these conditicns will cause an engine to have an increased tendency to detonate? 1. High manifold pressure. 2. High intake air temperature. 3. Engine overheated. 4. Late ignition timing.
1, 2, and 3
49
Oil accumulation in the cylinders of an inverted inline engine and in the lower cylinders of a radial engine is normally reduced or prevented by
extended cylinder skirts
50
Why does the smoothness of operation of an engine increase with a greater number of cylinders?
The power impulses are spaced closer together
51
Which of the following is a primary engine instrument
Tachometer
52
What unit in a tachometer system sends information to the indicator?
The three-phase AC generator
53
As the pressure is applied during a reciprocating engine compression check using a differential pressure tester, what would a movement of the propeller in the direction of engine rotation indicate?
The piston was positioned past top dead center
54
What is the purpose of the safety circlet installed on some valve stems?
To prevent valves from falling into the combustion chamber.
55
One function of the nozzle diaphragm in a turbine engine is to
direct the flow of gases to strike the turbine blades at a desired angle.
56
Some high-volume turboprop and turbojet engines are equipped with two-spool or split compressors. When these engines are operated at high altitudes, the
low-pressure rotor will increase in speed as the compressor load decreases in the lower density air.
57
What is an advantage of using metallic-sodium filled exhaust valves in aircraft reciprocating engines?
Reduced valve operating temperatures
58
The five events of a four-stroke cycle engine in the order of their occurence are
intake, compression, ignition, power, exhaust
59
Where are sludge chambets, when used in aircraft engine lubrication svstems, usually located?
In the crankshaft throws
60
When is the fuel/air mixture ignited in a conventional reciprocating engine?
Shortly before the piston reaches the top of the compression stroke.
61
The purpose of an exhaust gas analyzer is to indicate the
fuel/air ratio being burned in the cylinders
62
A nine-cylinder engine with a bore of 5.5 inches and a stroke of 6 inches will have a total piston displacement of
1,283 cubic inches
63
How is the oil coilected by the piston oil ring returned to the crankcase?
Through holes drilled in the piston oil ring groove
64
Valve overlap is defined as the number of degrees of crankshaft travel
during which both valves are off their seats
65
If the hot clearance is used to set the valves when the engine is cold, what will occur during operation of the engine?
The valves will open late and close early
66
Excessive oil is prevented from accurmulating on the cylinder walls of a reciprocating engine by
oil control rings on the pistons
67
Which statement is correct regarding engine crankshafts?
Moveable counterweights serve to reduce the dynamic vibraions in an aircraft reciprocating engine.
68
Which statement is true regarding a thermocouple type cylinder head temperature measuring system?
The voltage output of a thermocouple system is determined by the temperature difference between the two ends of the thermocouple.
69
Turbine nozzle diaphrags located on the upstream side of each turbine wheel are used in the gas turbine engine to
increase the velocity of the heated gases flowing past this point.
70
Excessive valve clearance in a piston engine
decrease valve overlap
71
Which of the following will decrease volumetric efficiency in a reciprocating engine? 1. Full throttle operation. 2. Low cylinder head temperatures. 3. Improper valve timing. 4. Sharp bends in the induction system. 5. High carburetor air temperatures.
3, 4, and 5
72
The primary concerm in establishing the firing order for an opposed engine is to
provide for balance and eliminate vibration the greatest extent possible.
73
Ignition occurs at 28° BTDC on a certain four-stroke cycle engine, and the intake valve opens at 15° BTDC. Aow many degrees of crankshrft travel after ignition does the intake valve open? (Consider one cylinder only.)
373°
74
An aircraft reciprocating engine using hydraulic valve lifters is observed to have no clearance in its valve-operating mechanism after the minimum inlet oil and cylinder head tenperatures for takeoff have been reached. When can this condition be expected?
During normal operation
75
At what speed nust a crankshaft turn if each cylinder of a four-stroke cycle engine is to be fired 200 times a minute?
400 RPM
76
A condition that can occur in radial engines but is uniikely to occur in horizontally opposed engines is
hydraulic lock
77
What is the purpose of a power check on a reciprocating engine?
To determine satisfactory performance
78
Wnat special procedure must be followed when adjustiug the valves of an engine equipped with a floating cam ring?
Eliminate cam bearing clearance when making valve adjustment
79
What section in the instructions for continued airworthiness is FAA approved?
Airworthiness limitations section
80
How many of the following are factors in establishing the maximum compression ratio limitation of an aircraft engine? 1. Detonation characteristics of the fuel used. 2. Design limitations of the engine. 3. Degree of supercharging. 4. Spark plug reach.
Three
81
If the oil pressure gauge fluctuates over a wide range from zero to normal operating pressure, the most likely cause is
low oil supply
82
Cam-round pistons are installed in some aircraft engines to
provide a better fit at operating temperature
83
If the intake valve is opened too early in the cycle of operation of a four-stroke cycle engine, it may result in
backfiring into the induction system
84
Master rod bearings are generally what type?
Plain
85
Which of the following results in a decrease in volumetric efficiency?
Part-throttle operation
86
Sodium-filled valves are advantageous to an aviation engine because they
dissipate heat well
87
The fuel-flow indicator rotor and needle for a motor-impeller and turbine indicating system is driven by
an electrical signal
88
standard sea level pressure is
29.92” Hg
89
The fuel-flow indication system used with many fuel-injected opposed engine airplanes utilizes a measure of
Fuel pressure
90
The purpose of two or more valve springs in aircraft engines is to
eliminate valve spring surge
91
Which unit most accurately indicates fuel consumption of a reciprocating engine?
Fuel flowmeter
92
The valve clearance of an engine using hydraulic lifters when the lifters are completely flat, or empty, should not exceed
a specified amount above zero
93
In an aircraft equipped with a pressure-drop type fuel-How indicating system. if one of the injector nozzles becomes restricted, this would cause a decrease in fuel flow with
an increase fuel flow indication on the gauge
94
Motor driven impeller and turbine fuel flow transnitters are designed to transmit data
using aircraft electrical system power
95
The undersides of pistons are frequently finned. The principal reason is to
provide for greater heat transfer to the engine oil
96
Where are the hot and cold junctions located in an engine cylinder temperature indicating system?
The hot junction is located at the cylinder and the cold junction is located at the instrument.
97
What could cause excessive pressure buildup in the crankcase of a reciprocating engine?
Plugged crankcase breather
98
Which of the following will be caused by excessive valve clearance of a cylinder on a reciprocating aircraft engine?
Reduced valve overlap period
99
Before attempting to starta radial engine that has been shut down for more than 30 minutes,
turn the propeller by hand hree to four revolutions in the normal direction of rotation to check for liquid lock.
100
The valve assemblies of opposed reciprocating engines are lubricated by means of a
pressure system