1
Q
foundation of an engine; usually made in two halves
A
crankcase
2
Q
contains the bearings and bearing supports in which the cranshaft revolves
A
crankcase
3
Q
Besides supporting itself, the crankcase must provide a _________ for the lubricating oil and must support various external and internal mechanisms of the engine
A
tight enclosure
4
Q
Crankcase also provides support for attachment of the cylinder assemblies, and the _______ to the aircraft.
A
powerplant
5
Q
A crankcase must be sufficiently rigid and strong to prevent _____________ and its bearings.
A
misalignment of the crankshaft
6
Q
__________ is generally used for crankcase construction because it is light and strong.
A
cast or forged aluminum alloy
7
Q
It is subjected to may variations of mechanical loads and other forces.
A
crankcase
8
Q
Since the cylinders are fastened to the crankcase, the tremendous forces placed on the cylinder tend to _____________.
A
pull the cylinder off the crankcase
9
Q
The unbalanced centrifugal and inertia forces of the crankshaft acting through the main bearings subject the crankcase to ______ which change continuously in direction and magnitude.
A
bending moments
10
Q
The crankcase must have sufficient ______ to withstand these bending moments without major deflections.
A
stiffness
11
Q
The shape of the nose or front of the crankcase section varies considerably, it is either _______ or ____>
A
tapered, round
12
Q
The machined surfaces on which the cylinders are mounted are called ______ or ______.
A
cylinder pads, cylinder mounting pads
13
Q
They are provided with a suitable means of retaining or fastening the cylinders to the crankcase.
A
cylinder pads, cylinder mounting pads
14
Q
The general practice in securing the cylinder flange to the pad is to mount ______ in threaded holes in the crankcase.
A
studs
15
Q
The inner portion of the cylinder pads are sometimes chamfered or tapered to permit the installation of a ________ around the _______, which effectively seals the joint between the cylinder and the crankcase pads against oil leakage.
A
large rubber O-ring, cylinder skirt
16
Q
Types of engine crankcases
A
opposed engine crankcase, radial engine crankcase
17
Q
A typical horizontally opposed engine cranckase consists of two halves of cast aluminum alloy that are manufactured either with ______ or by using ______.
A
sand castings, permanent molds
18
Q
Radial engine crankcases are divided into distinct sections. The number of sections can be as few as _____ or as many as ______ depending on the size and type of engine.
A
three, seven
19
Q
Four main sections of a typical radial engine crankcase
A
nose section, power section, supercharger section, accessory section
20
Q
It is mounted at the front of a radial engine crankcase and bolts directly to the power section.
A
Nose section
21
Q
It usually houses and supports a propller governor drive shaft, the propeller shaft, a cam ring, and a propeller reduction gear assembly if required.
A
nose section
22
Q
It represents the section of the crankcase where the reciprocating motion of the pistons is converted to the rotary motion of the crankshaft; supports cranshaft bearings, where cylinders are mounted.
A
main or power section
23
Q
It is located behind the power section and is generally made of cast aluminum alloy or magnesium.
A
diffuser or supercharger section
24
Q
This section houses the supercharger and its related components; provides housing for attachments of induction pipes and manifold pressure lines.
A
diffuser or supercharger section
25
The diffues or supercharger is also called as "________."
fuel induction and distribution section
26
It houses gear trains containing both spur- and bevel-type gears that drive various engine components and accessories; has mounting pads for fuel pump, oil pump, tachometer generators, etc.
accessory section
27
It is a shaft composed of one or more cranks located at specified points along its length.
crankshaft
28
The ____ or ____ are formed by forging offsets into a shaft before it is machined.
cranks, throws
29
Since crankshafts must be very strong, they generally are forged from a very strong alloy, such as ___________.
chromium-nickel-molybdenum steel
30
The crankshaft is carried in a position parallel to the _______ axis of the crankcase and is generally supported by a main bearing between each throw.
longitudinal
31
The crankshaft main bearings must be supported rigidly in the crankcase, usually accomplished by means of ______ in the crankcase, one for each main bearing.
transverse webs
32
The ________ form an integral part of the structure and, in addition to supporting the main bearings, add to the strength of the entire case.
transverse webs
33
A cranshaft may be of _____ or ____ construction.
single-piece, multi-piece
34
The _____ construction may be used either on four cylinder horizontal opposed or four-cylinder inline engines.
four-throw
35
The _____ shaft is used on six-cylinder inline engines, 12-cylinder V-type engines, and six-cylinder opposed engines.
six-throw
36
Cranshafts of radial engines may be the _____, ____< or _____ type, depending on whether the engine is the single-wor, twin-row, or four-row type.
single-throw, two-throw, four-throw
37
Three main parts of crankshaft
journal, crankpin, crank cheek/crank arm
38
_______ and _____, although not a true part of a crankshaft, are usually attached to it to reduce engine vibration.
counterweights, dampers
39
The ______ is supported by, and rotates in, a main bearing. It serves as the center of rotation of the crankshaft. It is surface-hardened to reduce _____.
journal, wear
40
The ______ is the section to which the connecting rod is attached.
crankpin
41
The crankpin is off-center from the main journals and is often called the _____.
throw
42
What makes a throw?
two crank cheeks and a crankpin
43
When a force is appiled to the crankpin in any direction other than parallel or perpendicular to and through the center line of the crankshaft, it causes the crankshaft to ______.
rotate
44
The crankpin is usually ______ which reduced the total weight of the crankshaft and provides a passage for the transfer of lubricating oil.
hollow
45
The outer surface is hardened by ______ to increase its resistance to wear and to provide the required bearing surface.
nitriding
46
It connects the crankpin to the main journal.
crank cheek
47
In some designs, the cheek extends beyond the journal and carries a _______ to balance the crankshaft.
counterweight
48
The crank cheek must be of sturdy construction to obtain the required rigidity between the ______ and the _____.
crankpin, journal
49
In all cases, the type of crankshaft and the number of crankpins must correspond with the _______ of the engine.
cylinder arrangement
50
The position of the cranks on the crankshaft in relation to the other cranks of the same shaft is expressed in _____.
degrees
51
The simplest crankshaft is the single-throw or _____ type.
360 deg
52
This type is used in a single-row radial engine and can be constructed in one or two pieces.
single-throw or 360 deg type
53
Two main bearings, one on each end, are provided when this type of crankshaft is used.
single-throw or 360 deg type
54
The _______ or _____ crankshaft is used on double-row radial engines. In the radial-type engine, one throw is provided for each row of cylinders.
double-throw, 180 deg
55
_______ in an engine not only result in fatigue failure of the metal structures, but also causes the moving parts to wear rapidly.
excessive vibration
56
In some instances, excessive vibration is caused by a crankshaft that is not ______.
balanced
57
Crankshafts are balanced for _____ and ______.
static balance, dynamic balance
58
A crankshaft is _______ when the weight of the entire assembly of crankpins, crank cheeks, and counterweights is balanced around the axis of rotation.
statically balanced
59
A crankshaft is __________ when all the forces created by crankshaft rotation and power impulses are balanced within themselves so that little or no vibration is produced when the engine is operating.
dynamically balanced
60
To reduce vibration to a minimum during engine operation, _____ are incorporated on the crankshaft.
dynamic dampers
61
A _______ is merely a pendulum that is fastened to the crankshaft so that it is free to move in a small arc. It is incorporated in the _________.
dynamic damper, counterweight assembly
62
In a dynamic damper, the difference in the diameter between the pins and the holes provides a ______.
pendulum effect
63
The portion of the engine in which the power is developed is called the ______.
cylinder
64
The cylinder provides a ________ where the burning and expansion of gases take place, and it houses the piston and the connecting rod.
combustion chamber
65
four major factors that need to be considered in the design and construction of the cylinder assembly
- must be strong enough to withstand internal pressures developed during engine operation
- be constructed of a lightweight metal to keep down engine weight
- have good heat-conducting properties for efficient cooling
- be comparatively easy and inexpensive to manufacture, inspect, and maintain
66
The cylinder head of an air-cooled engine is generally made of ______ because it is a good conductor of heat and its light weight reduces the ___________.
aluminum alloy, overall engine weight
67
Cylinder heads are ______ or _____ for greater strength.
forged, die-cast
68
The inner shape of a cylinder head is generally _______. This shape is generally stronger than other designs and aids in a more rapid and thorough scavenging of the exhaust gases.
semi-spherical
69
The cylinder used in the air-cooled engine is the ________.
overhead valve type
70
Two major parts of each cylinder
cylinder head, cylinder barrel
71
The majority of the cylinders used are constructed in the manner of gas-tight joint using an _____ head and a _____ barrel.
aluminum, steel
72
Its purpose is to provide a place for combustion of the fuel/air mixture and to give the cylinder more heat conductivity for adequate cooling.
cylinder head
73
The fuel/air mixture is ignited by the spark in the _________ and commences burning as the piston travels TDC on the compression stroke.
combustion chamber
74
The ignited charge is rapidly expanding at this time, and _______ is increased drastically so that the piston is driven downward on the power stroke.
pressure
75
The intake and exhaust valve ports are located in the _________ along with the spark plugs and the intake and exhaust valve actuating mechanisms.
cylinder head
76
__________ spark plug inserts are used in many engines currently manufactured.
Stainless steel Heli-Coil
77
The cylinder heads of air-cooled engines are subjected to ___________; it is therefore necessary to provide adequate cooling fin area and to use metals that conduct heat rapidly.
extreme temperatures
78
It is well adapted for casting or for the machining of deep, closely spaced fins, and it is more resistant than most metals to the corrosive attack.
Aluminum alloy
79
The ___________ is the hottest part of the internal surface; therefore, more fin area is provided around the outside of the cylinder head in this section.
exhaust valve region
80
This is where the piston operates; must be made of a high-strength material, usually steel; must be as light as possible, yet have the proper characteristics for operating under high temperatures and pressures; must be made of a good bearing material and have high tensile strength.
cylinder barrel
81
The cylinder barrel is made of a steel alloy forging with the inner surface hardened to resist wear of the __________ that bear against it.
piston and piston rings
82
The hardening in the cylinder barrel is usually done by exposing the steel to ______ or ______ while the steel is very hot. The metal is also said to be nitrided.
ammonia, cyanide gas
83
As the cylinder barrels wear due to use, they can be repaired by ________.
chroming
84
This is a process that plates chromium on the surface of the cylinder barrel and brings it back to new standard dimensions.
chroming
85
______ the cylinder walls is a process that brings it to the correct dimensions.
honing
86
Some engine cylinder barrels are choked at the top, or they are smaller in diameter to allow for _________ and _______.
heat expansion, wear
87
The valves used in aircraft engines are the ______________.
conventional poppet type
88
The valves are also typed by their shape and are called either ______ or _____ because of their resemblance to the shape of these plants.
mushroom, tulip
89
The valves in the cylinders are subjected to _______, _________, and __________; thus, the metal alloy in the valves must be able to resist all these factors.
high temperatures, corrosion, operating stresses
90
Because intake valves operate at lower temperatures than exhaust valves, they can be made of ________.
chromic-nickel steel
91
Exhaust valves are usually made of ______, ________, or ____________ because these materials are much more heat resistant.
nichrome, silchrome, cobalt-chromium steel
92
The valve head has a _____ that forms a seal against the __________ in the cylinder head when the valve is closed.
ground face, ground valve seat
93
The face of the valve is usually ground to an angle of either ____ or ____.
30 deg, 45 deg
94
In some engines, the intake-valve face is ground to an angle of _____, and the exhaust valve face is ground to a _____ angle.
30 deg, 45 deg
95
Some installations have the valves and valve seats ground ______ different to enhance the seal formed between the face of the valve and the valve seat.
1/2 deg
96
Valve faces are often made more durable by the application of a material called _________. About ______ inch of this alloy is welded to the valve face and ground to the correct angle.
stellite, 1/16
97
It is resistant to high temperature corrosion and also withstands the shock and wear associated with valve operation.
stellite
98
The _____ is the part that forms the junction between the head and the stem.
neck
99
The tip of the valve is hardened to withstand the hammering of the ______ as it opens the valve.
valve rocker arm
100
The ________ acts as a pilot for the valve head and rides in the valve guide installed in the cylinder head for this purpose. It is surface hardened to resist wear.
valve stem
101
A machined groove on the stem near the tip receives the _______. These form a lock ring to hold the valve spring retaining washer in place.
split-ring stem keys
102
The metallic sodium melts at approximately _____ and the reciprocating motion of the valve circulates the liquid sodium, allowing it to carry away heat from the valve head to the valve stem where it is dissipated through the valve guide to the cylinder head and the cooling fins.
208 deg fahrenheit
103
Some intake and exhaust valve stems are hollow and partially filled with _________. It is used because it is an excellent heat conductor.
metallic sodium
104
Intake valves for low-power engines are usually ______ headed.
flat
105
With the melted sodium, the operating temperature of the valve may be reduced as much as ____ deg Fahrenheit to _____ deg Fahrenheit.
300, 400
106
In some engines, the intake valve may be the tulip type and have a smaller stem than the exhaust valve or it may be similar to the exhaust valve but have a __________.
solid stem and head
107
Although these valves are similar, they are not interchangeable since the faces of the valves are constructed of _________.
different material
108
Under no circumstances should a sodium-filled valve be cut open or subjected to treatment that may cause it to rupture. Exposure of the sodium in these valves to the outside air results in _____ or _______ with possible personal injury.
fire, explosion
109
The most commonly used intake valves have ______, and the head is either flat or tulip shaped.
solid stems
110
The intake valve usually has a ______ on the tip to identify it. Also, the head of the intake valve typically has a larger diameter than the exhaust valve.
flat milled
111
It permits better volumetric efficiency and lowers the cylinder operating temperature.
valve overlap
112
This timing of the valves is controlled by the valve-operating mechanism and is referred to as the ______.
valve timing
113
The valve lift and valve duration are both determined by the shape of the _____.
cam lobes
114
The portion of the lobe that gently starts the valve operating mechanism moving is called a ____ or ____.
ramp, step
115
It is machined on each side of the cam lobe to permit the rocker arm to be eased into contact with the valve tip and thus reduce the shock load that would otherwise occur.
ramp
116
The valve operating mechanism consists of a cam ring (for radial engines) or camshaft equipped with lobes that work against a ____ or a _____.
cam roller, cam follower
117
It pushes a push rod and ball socket, actuating a rocker arm, which in turn opens the valve.
cam follower
118
_________, which slip over the stem of the valves and are held in place by the valve-spring retaining washer and stem key, close each valve, and push the valve mechanism in the opposite direction.
springs
119
It is a circular piece of steel with a series of cams or lobes on the outer surface.
cam ring
120
The surface of these lobes (cam rings) and the space between them (on which the cam rollers ride) is known as the _______.
cam track
121
As the cam ring revolves, the lobes cause the cam roller to raise the _______ in the tappet guide, thereby transmitting the force through the push rod and rocker arm to open the valve.
tappet
122
The _______ is mounted concentrically with the crankshaft and is driven by the crankshaft at a reduced rate of speed through the cam intermediate drive gear assembly.
cam ring
123
The timing of the valve events is determined by the ________ of these lobes and the speed and direction at which the cam rings are driven in relation to the speed and direction of the crankshaft.
spacing
124
It operates the valve mechanism of an opposed engine; it is driven by a gear that meshes with another gear attached to the crankshaft.
camshaft
125
The camshaft always rotates at ____ the crankshaft speed.
one-half
126
slides in an out in a tappet guide installed in one of the crankcase sections around the cam ring
cylindrical tappet
127
follows the contour of the cam ring and lobes
tappet roller or face
128
tappet/valve lifter assembly consists of the following
- cylindrical tappet
- tappet roller or face
- tappet ball socket or push rod socket
- tappet spring
129
Its function is to convert the rotational movement of the lobe into reciprocating motion and to transmit this motion to the push rod, rocker arm, and then to the valve tip, opening the valve at the proper time.
tappet assembly
130
Its purpose is to take up the clearance between the rocker arm and the valve tip to reduce the shock load when the valve is opened.
tappet spring
131
A hole is drilled through the tappet to allow engine oil to flow to the hollow push rods to lubricate the ___________.
rocker assemblies
132
generally require the valve clearance to be adjusted manually by adjusting a screw and lock nut
solid lifters or cam followers
133
needed to assure that the valve has enough clearance in the valve train to close completely
valve clearance
134
A number of aircraft engines in service today continue to use _______. This is especially the case with radial engines.
solid lifters
135
Some aircraft engines incorporate ___________ that automatically keep the valve clearance at zero when the engine is running, eliminating the necessity for any valve clearance adjustment mechanism.
hydraulic tappets
136
When the engine valve, intake or exhaust, is closed, the face of the tappet body (cam follower) is on the ______ or back of the cam.
base circle
137
The _________ lifts the hydraulic plunger so that its outer end contacts the push rod socket, exerting a light pressure against it, thus eliminating any clearance in the valve linkage.
light plunger spring
138
As the plunger moves outward, the ________ moves off its seat.
ball check valve
139
Oil from the supply chamber, which is directly connected with the engine lubrication system, flows in and fills the pressure chamber. As the camshaft rotates, the cam pushes the tappet body and the hydraulic lifter cylinder outward. This action forces the ball check valve onto its seat; thus, the body of oil trapped in the pressure chamber acts as a ________. Immediately after the valve closes, the amount of oil required to fill the pressure chamber flows in from the supply chamber, preparing for another cycle of operation.
cushion
140
The _______, tubular in form, transmits the lifting force from the valve tappet to the rocker arm.
push rod
141
Why is the push rod tubular in form?
because of its lightness and strength
142
The push rod further permits the engine lubricating oil to pass through the hollow rod and the drilled ball ends to lubricate the ______, _____, and ______.
ball ends, rocker-arm bearing, valve-stem guide
143
The push rod is enclosed in a tubular housing that extends from the crankcase to the cylinder head, referred to as ______.
push rod tubes
144
_____________ will cause the valve to open late and close early.
Excessive valve clearance
145
Too little clearance will have the opposite effect of causing the valves to open early and close late and may even prevent the valves closing at all, thereby producing an event called “________________."
popping back into the carburetor
146
These are self-adjusting and operate with no clearance and thus there is no tappet noise.
hydraulic tappets
147
made in two main parts, one sliding within the other
hydraulic tappet
148
supplied under pressure, causes the tappet to lengthen and take up any clearance when the engine is running
oil
149
Each valve is closed by _____ helical springs.
two or three
150
If a single spring were used, it would ______ or surge at certain speeds. To eliminate this difficulty, two or more springs (one inside the other) are installed on each valve.
vibrate
151
Two or more springs also reduce danger of weakness and possible failure by breakage due to __________.
heat and metal fatigue
152
Each spring vibrates at a different engine speed and _________ out of all spring-surge vibrations during engine operation results.
rapid damping
153
The springs are held in place by _______ installed in the recess of the valve spring upper retainer or washer and engage a groove machined into the valve stem.
split locks
154
The functions of the valve springs are to close the valve and to hold the valve securely on the ______.
valve seat
155
a cylindrical member that moves back and forth within a steel cylinder
piston
156
acts as a moving wall within the combustion chamber
piston
157
As the piston moves down in the cylinder, it draws in the __________.
fuel/air mixture
158
machined in the outside surface of the piston to receive the piston rings
grooves
159
top of the piston, or head, may be ____, _____, or ______
flat, convex, concave
160
may be machined in the piston head to prevent interference with the valves
recesses
161
modern engines use ______ that have a larger diameter perpendicular to the piston pin
cam-ground pistons
162
At low temperatures, the piston is ______ and when it warms to operating temperature, it becomes ______.
oval shaped, round
163
As many as ___ grooves may be machined around the piston to accommodate the compression rings and oil rings.
six
164
The _________ are installed in the uppermost grooves and the __________ are installed immediately above the piston pin.
compression rings, oil control rings
165
The piston is usually drilled at the _____________ to allow surplus oil scraped from the cylinder walls by the oil control rings to pass back into the crankcase.
oil control ring grooves
166
An ________ is installed at the base of some pistons to prevent excessive oil consumption.
oil scraper ring
167
The portions of the piston walls that lie between ring grooves are called the ________.
ring lands
168
In addition to acting as a guide for the piston head, the ______ incorporates the piston-pin bosses.
piston skirt
169
The _________ are of heavy construction to enable the heavy load on the piston head to be transferred to the piston pin.
piston-pin bosses
170
The majority of aircraft engine pistons are machined from ____________.
aluminum alloy forgings
171
joins the piston to the connecting rod
piston pin
172
sometimes called a wristpin because of the similarity between the relative motions of the piston and the connecting or articulated rod and that of the human arm
piston pin
173
also known as gudgeon pin
piston pin
174
The piston pin used in modern aircraft engines is the _________, so called because the pin is free to rotate in both the piston and in the connecting rod piston-pin bearing.
full-floating type
175
The ________ must be held in place to prevent the pin ends from scoring the cylinder walls.
piston pin
176
A plug of relatively _________ in the pin end provides a good bearing surface against the cylinder wall.
soft aluminum
177
________ are usually machined in the form of a tube from a nickel steel alloy forging, casehardened and ground.
Piston pins
178
prevent leakage of gas pressure from the combustion chamber and reduce to a minimum the seepage of oil into the combustion chamber
piston rings
179
The ________ fit into the piston grooves but spring out to press against the cylinder walls; when properly lubricated, the rings form an effective gas seal.
piston rings
180
Since their purpose is to seal the clearance between the piston and the cylinder wall, they must fit the cylinder wall snugly enough to provide a gas-tight fit.
piston ring construction
181
A piston ring construction must exert equal pressure at all points on the cylinder wall, and must make a gas-tight fit against the sides of the _______.
ring grooves
182
Its purpose is to prevent or minimize the escape of combustion gases past the piston during engine operation.
Compression Ring
183
They are placed in the ring grooves immediately below the piston head.
compression ring
184
The number of compression rings used on each piston is determined by the _____ and _______, although most aircraft engines use _____ compression rings plus one or more oil control rings.
type of engine, its design, two
185
The cross-section of the compression ring is either _______ or wedge shaped with a __________.
rectangular, tapered face
186
It presents a narrow bearing edge to the cylinder wall, which helps to reduce friction and provide better sealing.
tapered face
187
These are placed in the grooves immediately below the compression rings and above the piston pin bores.
oil control rings
188
There may be one or more oil control rings per piston; ____ rings may be installed in the same groove, or they may be installed in __________.
two, separate grooves
189
It regulates the thickness of the oil film on the cylinder wall.
oil control rings
190
If too much oil enters the combustion chamber, it burns and leaves a thick coating of ________ on the combustion chamber walls, the piston head, the spark plugs, and the valve heads.
carbon
191
If too much oil enters the combustion chamber, it burns and leaves a thick coating of carbon on the ____________, the __________, the ______, and the ________.
combustion chamber walls, piston head, spark plugs, valve heads
192
This carbon left if too much oil enters the combustion chamber can cause the valves and piston rings to stick if it enters the _________ or _________.
ring grooves, valve guides
193
The carbon can cause __________ as well as detonation, pre-ignition, or excessive oil consumption.
spark plug misfiring
194
The carbon can cause spark plug misfiring as well as _______, _________, or ____________.
detonation, pre-ignition, excessive oil consumption
195
To allow the surplus oil to return to the crankcase, holes are drilled in the _____ of the oil control piston ring grooves or in the lands next to these grooves.
bottom
196
Most piston rings are made of _________. After the rings are made, they are ground to the cross-section desired. Then they are split so that they can be slipped over the _________ and into the ___________ that are machined in the piston wall.
high-grade cast iron, outside of the piston, ring grooves
197
_____________ is most often used in making piston rings.
gray cast iron
198
In some engines, ____________ piston rings are used in the top compression ring groove because these rings can better withstand the __________ present at this point.
chrome-plated mild steel, high temperatures
199
Chrome rings must be used with ________. Never use chrome rings on _______. Technicians must correctly select, fit, and install piston rings to ensure proper engine operation.
steel cylinder walls, chrome cylinders
200
It is the link that transmits forces between the piston and the crankshaft.
connecting rod
201
___________ must be strong enough to remain rigid under load and yet be light enough to reduce the inertia forces that are produced when the rod and piston stop, change direction, and start again at the end of each stroke.
Connecting rods
202
This type of connecting rod is used in inline and opposed engines.
plain-type connecting rods
203
The end of the plain-type connecting rod attached to the ______ is fitted with a cap and a two-piece bearing.
crankpin
204
The bearing cap in a plain-type connecting rod is held on the end of the rod by _____ or ______.
bolts, studs
205
This connecting rod assembly is used primarily in V-type engines.
fork-and-blade rod assembly
206
In a fork-and-blade rod assembly, the forked rod is split at the crankpin end to allow space for the blade rod to fit between the _____.
prongs
207
A _______ bearing is used on the crankshaft end of the rod in a fork-and-blade rod assembly.
single two-piece
208
This rod assembly is commonly used in radial engines.
master-and-articulated rod assembly
209
In a radial engine, the piston in one cylinder in each row is connected to the crankshaft by a _______. All other pistons in the row are connected to the master rod by ________.
master rod, articulated rods
210
The _______ serves as the connecting link between the piston pins and the crankpin.
master rod
211
The crankpin end, or the big end, contains the _______ or ________.
crankpin, master rod bearing
212
_______ around the big end provide for the attachment of the articulated rods.
flanges
213
he articulated rods are attached to the master rod by ________, which are pressed into holes in the master rod flanges during assembly.
knuckle pins
214
A _________, usually called a ________, is installed in the piston end of the master rod to receive the piston pin.
plain bearing, piston-pin bushing
215
A _____ connecting rod assembly is a special type of master and articulated rod assembly.
split-type
216
In engines that use the one-piece type of crankshaft, the big end of the master rod is _______, as is the master rod bearing.
split
217
The master and articulated rods are assembled and then installed on the ________; the ___________ are then joined together.
crankpin, crankshaft sections
218
The centers of the knuckle pins do not coincide with the center of the crankpin. Thus, while the crankpin center describes a true circle for each revolution of the crankshaft, the centers of the knuckle pins describe an _________.
elliptical path
219
The main part of the master rod is installed on the _______; then the ___________ is set in place and bolted to the master rod.
crankpin, bearing cap
220
The elliptical paths are symmetrical about a center line through the master rod cylinder. It can be seen that the major diameters of the ellipses are not the same. Thus, the link rods have varying degrees of angularity relative to the __________.
center of the crank throw
221
Because of the varying _________ of the link rods and the _________ of the knuckle pins, all pistons do not move an equal amount in each cylinder for a given number of degrees of crank throw movement. This variation in piston position between cylinders can have considerable effect on engine operation.
angularity, elliptical motion
222
To minimize the effect of these factors (angularity variation, elliptical motion) on valve and ignition timing, the knuckle pin holes in the master rod flange are _________ from the center of the crankpin, thereby offsetting to an extent the effect of the link rod angularity.
not equidistant
223
The _________ are of solid construction except for the oil passages drilled in the pins, which lubricate the knuckle pin bushings.
knuckle pins
224
These pins may be installed by pressing into holes in the master rod flanges so that they are prevented from turning in the master rod.
knuckle pins
225
Knuckle pins may also be installed with a ________ so that they can turn in the master rod flange holes, and also turn in the articulating rod bushings.
loose fit
226
Knuckle pins installed with a loose fit are called ______________.
full-floating knuckle pins
227
In either type of installation, a _______ on each side retains the knuckle pin and prevents a lateral movement.
lock plate
228
The increased brake horsepower delivered by a high horsepower engine results partly from ____________.
increased crankshaft rpm
229
It is necessary to provide reduction gears to limit the __________ to a value at which efficient operation is obtained.
propeller rotation speed
230
Whenever the speed of the blade tips approaches the speed of sound, the efficiency of the propeller ___________.
decreases rapidly
231
Reduction gearing for engines allows the engine to operate at a _______, developing _________ while slowing down the __________ which prevents the propeller efficiency from decreasing.
higher rpm, more power, propeller rpm
232
three most commonly used type of propeller reduction gearing
- spur planetary
- bevel planetary
- spur and pinion
233
The _________ reduction gearing consists of a large driving gear or sun gear splined (and sometimes shrunk) to the crankshaft, a large stationary gear, called a bell gear, and a set of small spur planetary pinion gears mounted on a carrier ring.
spur planetary
234
The spur planetary reduction gearing consists of a large driving gear or sun gear splined (and sometimes shrunk) to the crankshaft, a large stationary gear, called a ________, and a set of small spur planetary pinion gears mounted on a ________.
bell gear, carrier ring
235
The _________ is fastened to the propeller shaft and the planetary gears mesh with both the sun gear and the stationary bell or ring gear.
carrier ring
236
The stationary gear is bolted or splined to the front section housing. When the engine is operating, the _______ rotates. Because the planetary gears are meshed with this ring, they also must rotate.
sun gear
237
Since the planetary gears also mesh with the stationary gear, they walk or roll around it as they rotate, and the ring in which they are mounted rotates the _________ in the same direction as the crankshaft but at ______ speed.
propeller shaft, reduced
238
In the _________ reduction gearing system, the driving gear is machined with beveled external teeth and is attached to the crankshaft.
bevel planetary
239
In the bevel planetary reduction gearing system, the driving gear is machined with _________ and is attached to the crankshaft.
beveled external teeth
240
A set of mating bevel pinion gears is mounted in a cage attached to the _______________-.
end of the propeller shaft
241
In bevel planetary, the _________ are driven by the drive gear and walk around the stationary gear, which is bolted or splined to the front section housing.
pinion gears
242
This type of planetary reduction assembly is more compact and can be used where a smaller propeller gear step-down is desired.
bevel planetary
243
In the case of ______________, more than one stage of reduction gearing is used due to the high output speeds of the engine.
gas turbine turboprop engines
244
Several types of lower powered engines can use the _______ reduction gear arrangement.
spur and pinion
245
Since reduction gearing must withstand extremely high stresses, the gears in the spur and pinion reduction gear arrangement are machined from _______.
steel forgings
246
Three types of propeller shafts
tapered, splined, flanged
247
This type of propeller shafts were used on most of the early, low-powered engines.
tapered propeller shafts
248
On a tapered propeller shaft, the ________ tapers toward the end of the shaft.
shaft diameter
249
To prevent a propeller hub from rotating on a tapered shaft, one or more _________ are milled into the shaft. In addition, the end of the shaft is threaded to receive a ___________.
key slots, propeller retaining nut
250
The propeller shaft of high-output radial engines is generally ________. It is threaded on one end for a ________.
splined, propeller hub nut
251
A ______ is a rectangular groove that is machined into the propeller shaft.
spline
252
Most splined shafts have a _______ that is approximately ________ the size of any other spline.
master spline, twice
253
The master spline assures that a propeller is attached to a propeller shaft a specific way so that vibration is kept to a ________.
minimum
254
The ________ assures that a propeller is attached to a propeller shaft a specific way so that vibration is kept to a minimum.
master spline
255
__________ are used on most modern reciprocating and turboprop engines.
Flanged propeller shafts
256
In a flanged propeller shaft, the shaft is forged with a _______ on its end. A propeller is bolted directly to the flange.
flat flange
257
To provide additional support for the propeller, most flanged propeller shafts incorporate a _______ forward of the flange and a ________ around the flange circumference.
short shaft, series of studs
258
On some engines, it is cast in one piece and provided with means for mounting the accessories, such as magnetos, carburetors, fuel, oil, vacuum pumps, starter, generator, tachometer drive, etc., in the various locations required to facilitate accessibility.
Accessory Section
259
The part of an engine that provides
the necessary mounting pads for accessory units such
as magnetos, fuel pumps, oil pumps, and generators.
Accessory Section
260
_________ are mounted in suitable drive arrangements that are carried out to the accessory mounting pads.
Accessory drive shafts
261
Through the accessory drive shafts being mounted in suitable drive arrangements that are carried out to the accessory mounting pads, the various ________ can be arranged to give the proper _______ to magnetos, pumps, and other accessories to obtain correct timing or functioning.
gear ratios, drive speed
262
The accessory (rear) section usually is of ________ and the material may be either ________, which is used most widely, or ______, which has been used to some extent.
cast construction, aluminum alloy, magnesium
263
_________, containing both spur- and bevel-type gears, are used in the different types of engines for driving engine components and accessories.
Gear trains
264
________ are generally used to drive the heavier loaded accessories or those requiring the least play or backlash in the gear train.
Spur-type gears
265
________ permit angular location of short stub shafts leading to the various accessory mounting pads.
Bevel gears
266
Bevel gears permit angular location of _________ leading to the various accessory mounting pads.
short stub shafts
267
On ________ reciprocating engines, the accessory gear trains are usually simple arrangements. Many of these engines use simple gear trains to drive the engine’s accessories at the proper speeds.
opposed
268
Reciprocating aircraft engines have ______ that are used as part of the oil system located at the low point of the engine.
sumps
269
These are used to collect oil circulating through the engine after the oil has completed its tasks.
sumps
270
Two types of sump
wet sump, dry sump
271
A _______ engine pumps the oil from the engine’s crankcase to an external tank that stores the oil. This system uses a scavenge pump, some external tubing, and an external tank to store the oil.
dry sump
272
______ engines use the sump as the storage tank for the oil. Oil departs the oil sump, passes through the engine, and returns to the oil sump beneath the engine.
wet sump
273
Because the oil remains in the engine, with the exception that it may travel to a remote oil cooler, the engine is classified as a ____ sump design.
wet
274
_______ engines store their oil in a remote tank; have oil quantities that are comparatively large than that of in the other sump engine. It would not be practical to keep those quantities of oil within the engine.
dry sump
275
The _______ is used to collect the oil that has passed through the engine and return the oil to the oil tank.
oil sump
276
A ________ is used to transfer the oil from the dry sump to the oil tank.
scavenge oil pump
277
The oil returning to the oil tank from the sump passes through an _______.
oil cooler
Powerplant I
flashcards
Decks in class (3)
# Cards
