問題一覧
1
When is the fuel/air mixture ignited in a conventional reciprocating engine?
Shortly before the piston reaches the top of the compression stroke.
2
Direct mechanical push-pull carburetor heat control linkages should normally be adjusted so that the stop located on the diverter valve will be contacted
before the stop at the control lever is reached in both HOT and COLD positions.
3
At what speed must a crankshaft turn if each cylinder of a four-stroke cycle engine is to be fired 200 times a minute?
400 RPM
4
Excessive valve clearance in a piston engine
decreases valve overlap.
5
On which part of the cylinder walls of a normally operating engine will the greatest amount of wear occur?
Near the top of the cylinder.
6
During the inspection of an engine control system in which push-pull control rods are used, the threaded rod ends should
Be checked for the amount of thread engagement by means of the inspection holes.
7
Some aircraft engine manufactures equip their product with choked or taper-ground cylinders in order to
Provide a straight cylinder bore at operating temperatures.
8
An unsupercharged aircraft reciprocating engine, operated at full throttle from sea level, to 10,000 feet, provided the RPM is unchanged, will
Lose power due to the reduce density of the air drawn into the cylinders.
9
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.
10
The valve clearance of an engine using hydraulic lifters, when the lifters are completely flatl, or empty, should not exceed
a specified amount above zero.
11
What does valve overlap promote?
Better scavenging and cooling characteristics.
12
During ground check an engine is found to be rough-running, the magneto drop is normal, and the manifold pressure is higher than normal for any given RPM. The trouble may be caused by
a dead cylinder.
13
During routine inspection of a reciprocating engine, a deposit of small , bright , metallic particles which do not cling to the magnetic drain plug is discovered in the oil sump and on the surface of the oil filter. This condition
may be a result of abnormal plain type bearing wear and is cause for further investigation.
14
Master rod bearings are generally what type?
plain
15
A hissing sound from the exhaust stacks when the propeller is being pulled through manually indicates
exhaust valve blow-by
16
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
17
When will small induction system air leaks have the most noticeable effect on engine operation?
At low RPM.
18
What special procedure must be followed when adjusting the values of an engine equipped with a floating cam ring?
Eliminate cam bearing clearance when making valve adjustment.
19
Valve overlap is defined as the number of degrees of crankshaft travel
during which both valves are off their seats.
20
Which of the following engine servicing operations generally requires engine pre-oiling prior to starting the engine?
Engine installation.
21
What is the best indication of worn valve guides?
High oil consumption.
22
How may it be determined that a reciprocating engine with a dry sump is pre-oiled sufficiently?
Oil will flow from engine return line or indicator port.
23
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.
24
Excessive valve clearances will cause the duration of valve opening to
decrease for both intake and exhaust valves.
25
Which statement is correct regarding a four-stroke cycle aircraft engine?
The intake valve closes on the compression stroke.
26
A characteristic of dyna-focal engine mounts as applied to aircraft reciprocating engines is that the
shock mount point toward the engine’s center of gravity.
27
Which statement pertaining to fuel/air ratios is true?
The mixture ratio which gives the best power is richer than the mixture ratio which gives maximum economy.
28
One cause of after firing in an aircraft engine is
an excessively rich mixture.
29
The horsepower developed in the cylinders of a reciprocating engine is known as the
indicated horsepower
30
An increase in manifold pressure with a constant RPM will cause the bearing load in an engine to
increase
31
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
32
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
33
The primary purpose in setting proper valve timing and overlap is to
obtain the best volumetric efficiency and lower cylinder operating temperatures.
34
Engine crankshaft run out is usually checked 1. during engine overhaul. 2. during annual inspection. 3. after a “prop strike” or sudden engine stoppage. 4. during 100–hour inspection.
1 and 3
35
A condition that can occur in radial engines but is unlikely to occur in horizontally opposed engines is
hydraulic lock.
36
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.
37
Excessive valve clearance results in the valves opening
late and closing early.
38
What will be the likely result if the piston ring gaps happen to be aligned when performing a differential-pressure compression check on a cylinder?
A worn or defective ring(s) indication.
39
Engine operating flexibility is the ability of the engine to
run smoothly and give the desired performance at all speeds
40
An engine misses in both the right and left positions of the magneto switch. The quickest method for locating the trouble is to
check for one or more cold cylinders.
41
After spark plugs from an opposed engine have been serviced, in what position should they be reinstalled?
Next in firing order to the one from which they were removed and swapped bottom to top.
42
Grinding the valves of a reciprocating engine to a feather edge is likely to result in
Pre-ignition and burned valves.
43
Which of these conditions 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, 3
44
Standard aircraft cylinder oversizes usually range from 0.010 inch to 0.030 inch. Oversize on automobile engine cylinders may range up to 0.100 inch. This is because aircraft engine cylinders
have relatively thin walls and may be nitrided.
45
The purpose of two or more valve springs in aircraft engines is to
eliminate valve spring surge.
46
What could cause excessive pressure buildup in the crankcase of a reciprocating engine?
Plugged crankcase breather.
47
By use of a differential pressure compression tester, it is determined that the No. 3 cylinder of a nine-cylinder radial engine will not hold pressure after the crankshaft has been rotated 2600 from top dead center compression stroke No. 1 cylinder. How can this indication usually be interpreted?
A normal indication.
48
One of the best indicators of reciprocating engine combustion chamber problems is
spark plug condition.
49
If the ignition switch is moved from BOTH to either LEFT or RIGHT during a magneto check, a normal operation is usually indicated by
slight drop in RPM.
50
The primary concern in establishing the firing order for an opposed engine is to
provide for balance and eliminate vibration to the greatest extent possible.