問題一覧
1
Which of the following will be caused by excessive valve clearance of a cylinder on a reciprocating aircraft engine?
Reduced valve overlap period.
2
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
3
During overhaul, reciprocating engine exhaust valves are checked for stretch
with a contour or radius gauge
4
What is the purpose of a power check on a reciprocating engine?
To determine satisfactory performance
5
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.
6
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
7
What tool is generally used to measure the crankshaft rotation in degrees?
Timing disk
8
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
9
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.
10
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.
11
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.
12
Which of the following conditions would most likely lead to detonation?
Use of fuel with too low an octane rating.
13
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
14
On which strokes are both valves on a four-stroke cycle reciprocating aircraft engine open?
Exhaust and intake
15
Valve clearance changes on opposed-type engines using hydraulic lifters are accomplished by
push rod replacement
16
Full-floating piston pins are those which allow motion between the pin and
both the piston and the small end of the connecting rod
17
Backfiring through the carburetor generally results from the use of
an excessively lean mixture.
18
If an engine cylinder is to be removed, at what position in the cylinder should the piston be?
Top dead center
19
(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.
20
The operating temperature valve clearance of a radial engine as compared to cold valve clearance is
greater
21
Which statement is correct regarding engine crankshafts?
Moveable counterweights serve to reduce the torsional vibrations in an aircraft reciprocating engine.
22
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.
23
Compression ratio is the ratio between the
cylinder volume with piston at bottom dead center and at top dead center
24
If the crankshaft run out readings on the dial indicator are plus .002 inch and minus .003 inch, the run out is
.005 inch
25
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.
26
What is the purpose of the safety circlet installed on some valve stems?
To prevent valves from falling into the combustion chamber.
27
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
28
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.
29
Which condition would be the least likely to be caused by failed or failing engine bearings?
Low oil temperatures
30
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.
31
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°
32
If the oil pressure of a cold engine is higher than at normal operating temperatures, the
engines lubrication system is probably operating normally.
33
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
34
Which of the following would most likely cause a reciprocating engine to backfire through the induction system at low RPM operation?
Lean mixture
35
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.
36
To what altitude will a turbo charged engine maintain sea level pressure?
Critical altitude
37
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
38
(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
39
What is an advantage of using metallic-sodium filled exhaust valves in aircraft reciprocating engines?
Reduced valve operating temperatures.
40
Some cylinder barrels are hardened by
nitriding.
41
The five events of a four-stroke cycle engine in the order of their occurrence are
intake, compression, ignition, power, exhaust.
42
The actual power delivered to the propeller of an aircraft engine is called
brake horsepower
43
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.
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
Which bearing is least likely to be a roller or ball bearing?
Master rod bearing (radial engine)
46
Cam-ground pistons are installed in some aircraft engines to
provide a better fit at operating temperatures
47
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.
48
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.
49
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°
50
If the oil pressure gauge fluctuates over a wide range from zero to normal operating pressure, the most likely cause is
low oil supply
51
Why does the smoothness of operation of an engine increase with a greater number of cylinders?
The power impulses are spaced closer together.
52
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.
53
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.
54
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
55
The floating control thermostat, used on some reciprocating engine installations, helps regulate oil temperature by
controlling air flow through the oil cooler
56
Which of the following is a characteristic of a thrust bearing used in most radial engines?
Deep-groove ball
57
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