問題一覧
1
Increased water vapor (higher relative humidity) in the incoming air to a reciprocating engine will normally result in which of the following?
Decreased engine power at a constant RPM and manifold pressure.
2
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.
3
Which fuel/air mixture will result in the highest engine temperature (all other factors remaining constant)?
A mixture leaner than a manual lean mixture of .060
4
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.
5
Which bearing is least likely to be a roller or ball bearing?
Master rod bearing (radial engine)
6
On which strokes are both valves on a four-stroke cycle reciprocating aircraft engine open?
Exhaust and intake
7
To reduce the power output of an engine equipped with a constant-speed propeller and operating near maximum BMEP, the
manifold pressure is reduced with the throttle control before the RPM is reduced with the propeller control.
8
Which of the following would indicate a general weak-engine condition when operated with a fixed-pitch propeller or test club?
Lower than normal static RPM, full throttle operation
9
Some cylinder barrels are hardened by
nitriding.
10
Why does the smoothness of operation of an engine increase with a greater number of cylinders?
The power impulses are spaced closer together.
11
Which of the following is a characteristic of a thrust bearing used in most radial engines?
Deep-groove ball
12
Which condition would be the least likely to be caused by failed or failing engine bearings?
Low oil temperatures
13
Valve clearance changes on opposed-type engines using hydraulic lifters are accomplished by
push rod replacement
14
The floating control thermostat, used on some reciprocating engine installations, helps regulate oil temperature by
controlling air flow through the oil cooler
15
Which of the following would most likely cause a reciprocating engine to backfire through the induction system at low RPM operation?
Lean mixture
16
What is the purpose of a power check on a reciprocating engine?
To determine satisfactory performance
17
To what altitude will a turbo charged engine maintain sea level pressure?
Critical altitude
18
Before attempting to start a radial engine that has been shut down for more than 30 minutes,
turn the propeller by hand three to four revolutions in the normal direction of rotation to check for liquid lock.
19
If the crankshaft run out readings on the dial indicator are plus .002 inch and minus .003 inch, the run out is
.005 inch
20
Full-floating piston pins are those which allow motion between the pin and
both the piston and the small end of the connecting rod
21
During overhaul, the disassembled parts of an engine are usually degreased with some form of mineral spirits solvent rather than water-mixed degreasers primarily because
water-mixed degreaser residues may cause engine oil contamination in the overhauled engine.
22
When does valve overlap occur in the operation of an aircraft reciprocating engine?
At the end of the exhaust stroke and the beginning of the intake stroke
23
Which statement is correct regarding engine crankshafts?
Moveable counterweights serve to reduce the torsional vibrations in an aircraft reciprocating engine.
24
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
25
Which of the following is most likely to occur if an overhead valve engine is operated with inadequate valve clearances?
The valves will not seat positively during start and engine warm up
26
If metallic particles are found in the oil filter during an inspection,
the cause should be identified and corrected before the aircraft is released for flight
27
The five events of a four-stroke cycle engine in the order of their occurrence are
intake, compression, ignition, power, exhaust.
28
Ignition occurs at 28° BTDC on a certain four-stroke cycle engine, and theintake valve opens at 15° BTDC. How many degrees of crankshaft travel after ignition does the intake valve open? (Consider one cylinder only).
373°
29
What is required by 14 CFR Part 43 Appendix D when performing an annual/100-hour inspection on a reciprocating engine aircraft?
Cylinder compression check.
30
Backfiring through the carburetor generally results from the use of
an excessively lean mixture.
31
Reduced air density at high altitude has a decided effect on carburetion, resulting in a reduction of engine power by
excessively enriching the fuel/air mixture.
32
Which of the following conditions would most likely lead to detonation?
Use of fuel with too low an octane rating.
33
How many of the following are factors in establishing the maximum compression ratio limitations 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
34
Cam-ground pistons are installed in some aircraft engines to
provide a better fit at operating temperatures
35
What is an advantage of using metallic-sodium filled exhaust valves in aircraft reciprocating engines?
Reduced valve operating temperatures.
36
The operating temperature valve clearance of a radial engine as compared to cold valve clearance is
greater
37
When cleaning aluminum and magnesium engine parts, it is inadvisable to soak them in solutions containing soap because
some of the soap will become impregnated in the surface of the material and subsequently cause engine oil contamination and foaming.
38
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 700: BBDC. Intake closes 45°: ABDC. Exhaust closes 10°: ATDC.
245°
39
What tool is generally used to measure the crankshaft rotation in degrees?
Timing disk
40
How is proper end-gap clearance on new piston rings assured during the overhaul of an engine?
By placing the rings in the cylinder and measuring the end-gap with a feeler gauge.
41
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 temperatures for takeoff have been reached. When can this condition be expected?
During normal operation
42
Compression ratio is the ratio between the
cylinder volume with piston at bottom dead center and at top dead center
43
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.
44
If an engine operates with a low oil pressure and a high oil temperature, the problem may be caused by a
leaking oil dilution valve
45
What is likely to occur if a reciprocating engine is operated at high power settings before it is properly warmed up?
Oil starvation of bearings and other parts.
46
What is the basic operational sequence for reducing the power output of an engine equipped with a constant-speed propeller?
Reduce the manifold pressure, then the RPM.
47
Which of the following will be caused by excessive valve clearance of a cylinder on a reciprocating aircraft engine?
Reduced valve overlap period.
48
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.
49
(1) Pre-ignition is caused by improper ignition timing. (2) Detonation occurs when an area of the combustion chamber becomes incandescent and ignites the fuel/air mixture in advance of normal timed ignition. Regarding the above statements,
neither No. 1 nor No. 2 is true.
50
If an engine cylinder is to be removed, at what position in the cylinder should the piston be?
Top dead center
51
During overhaul, reciprocating engine exhaust valves are checked for stretch
with a contour or radius gauge
52
The actual power delivered to the propeller of an aircraft engine is called
brake horsepower
53
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
54
If the oil pressure gauge fluctuates over a wide range from zero to normal operating pressure, the most likely cause is
low oil supply
55
What is the purpose of the safety circlet installed on some valve stems?
To prevent valves from falling into the combustion chamber.
56
If the oil pressure of a cold engine is higher than at normal operating temperatures, the
engines lubrication system is probably operating normally.
57
(1) Cast iron piston rings may be used in chrome-plated cylinders. (2) Chrome-plated rings may be used in plain steel cylinders. Regarding the above statements,
both No. 1 and No. 2 are true