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finals Flashcards

1
Q

The basic principles of engine operation is the relationship between:

A

Pressure
* Volume
* Temperature

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2
Q

is a
device for converting heat energy into
mechanical energy.

A

internal combustion engine

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3
Q

is the distance the
piston moves from one end of the cylinder
to the other, specifically from top dead
center (TDC) to bottom dead center
(BDC), or vice versa.

A

stroke

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4
Q

Aircraft engines can be classified by several methods. They can be classed by:

A
  • Operating cycles
  • Cylinder arrangement
  • The method of thrust production
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5
Q

All are heat engines that convert fuel into 1._______that is converted to 2.______ to
produce thrust.

A

1.heat energy
2.mechanical energy

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6
Q

Most of the current aircraft engines are of the internal combustion type because

A

the
combustion process takes place inside the engine.

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7
Q

Reciprocating engines may be classified by:

A
  • the cylinder arrangement (in line, V-type, radial, and opposed).
  • method of cooling (liquid cooled or air cooled).
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8
Q

y. Today, most of
the engines currently (2005) manufactured by1._________ are used by
major manufacturers of light aircraft Cirrus, Cessna and so on.

A
  1. Lycoming and Continental
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9
Q

rely on the circulation of air
directly over heat dissipation fins or hot areas of
the engine to cool them in order to keep the engine
within operating temperatures.

A

Air-cooled engines

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10
Q

In all combustion
engines, a great percentage of the heat generated
(1.____) escapes through the exhaust, not
through the metal fins of an air-cooled engine (2.___).
About 3.____ of the heat energy is transferred to the oil,
which although primarily meant for lubrication, also
plays a role in heat dissipation via a cooler.

A

1.around 44%
2.12%
3. 8%

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11
Q

, the heat is transferred from the cylinders to the coolant, which is then sent through tubing
and cooled within a radiator placed in the airstream.

A

liquid-cooled engines

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12
Q

The main problem with liquid cooling is

A

the added weight of coolant, heat exchanger (radiator), and
tubing to connect the components.

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13
Q

If the engine is designed to
operate with the cylinders below the crankshaft, it
is called an

A

inverted engine

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14
Q

generally has an even number
of cylinders, although some three-cylinder
engines have been constructed.

A

inline engine

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15
Q

has two banks of
cylinders directly opposite each other with
a crankshaft in the center.

A

opposed-type engine

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16
Q

, the cylinders are
arranged in two in-line banks generally set
60° apart.

A

V-type engines

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17
Q

consists of a row, or rows, of
cylinders arranged radially about a central crankcase.

A

radial engine

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18
Q

Some radial
engines have two rows of seven or nine cylinders
arranged radially about the crankcase, one in front of
the other. These are called

A

double- row radials

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19
Q

There are several operating cycles in use:

A
  1. Four stroke
  2. Two stroke
  3. Rotary
  4. Diesel
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20
Q

,
sometimes called the Otto cycle after its originator, a German physicist.

A

four-stroke cycle

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21
Q

During the _______, the piston is pulled
downward in the cylinder by the rotation of the
crankshaft.

A

intake stroke

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22
Q

After the intake valve is closed, the continued upward
travel of the piston compresses the fuel/air mixture to
obtain the desired burning and expansion characteristics.

A

Compression Stroke

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23
Q

As the piston moves through the TDC position at the
end of the compression stroke and starts down on the

A

power stroke.

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24
Q

As the piston travels through BDC at the
completion of the power stroke and starts upward
on the

A

exhaust stroke

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25
Q

The timing of the valve and ignition
events is always specified in degrees of
crankshaft travel.

A

Valve Timing and Valve Overlap

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26
Q

has re-emerged
being used in ultra-light, light sport, and many
experimental aircraft.

A

two-stroke-cycle engine

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27
Q

has a three-sided rotor
that turns inside an elliptical housing,
completing three of the four cycles for
each revolution.

A

rotary cycle

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28
Q

depends on high
compression pressures to provide for the
ignition of the fuel/air charge in the
cylinder.

A

diesel cycle

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29
Q

The basic major components of a reciprocating engine are

A

the crankcase, cylinders, pistons, connecting
rods, valves, valve-operating mechanism, and crankshaft.

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30
Q

The foundation of an engine is the

A

crankcase.

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31
Q

The shape of the nose or front of the crankcase
section varies considerably. In general, it is either
.

A

tapered or round

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32
Q

usually is of cast
construction and the material may be either
aluminum alloy, which is used most widely, or
magnesium, which has been used to some extent.

A

accessory (rear) section

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33
Q

, containing both spur- and beveltype gears, are used in the different types of
engines for driving engine components and
accessories.

A

Gear trains

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34
Q

are generally
used to drive the heavier loaded accessories or
those requiring the least play or backlash in
the gear train.

A

Spur-type gears

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35
Q

permit angular
location of short stub shafts leading to the
various accessory mounting pads.

A

Bevel gears

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36
Q

is carried in a position parallel to the longitudinal axis of the crankcase and is
generally supported by a main bearing between each throw.

A

crankshaft

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37
Q

Its main purpose is to transform the reciprocating motion of the piston and connecting rod
into rotary motion for rotation of the propeller

A

crankshaft

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38
Q

, each crankshaft has
three main parts—

A

a journal, crankpin, and crank cheek.

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39
Q

is supported by, and rotates in, a main bearing. It
serves as the center of rotation of the crankshaft.

A

journal

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40
Q

is the section to which the connecting rod is
attached.

A

crankpin

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41
Q

and a crankpin make a throw. When a
force is applied 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.

A

Two crank cheeks

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42
Q

Excessive vibration in an engine not only results in fatigue failure of the metal structures, but also causes
the moving parts to wear rapidly.

A

Crankshaft Balance

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43
Q

is merely a pendulum that is fastened to the
crankshaft so that it is free to move in a small arc.

A

dynamic damper

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44
Q

is the link that transmits forces between the piston and the crankshaft.

A

connecting rod

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45
Q

There are four types of connecting-rod assemblies:

A
  1. Plain
  2. Fork and blade
  3. Master and articulated
  4. Split-type
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46
Q

are used in inline and opposed engines.

A

Plain-type connecting rods

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47
Q

is
commonly used in radial engines.

A

master-and-articulated rod assembly

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48
Q

serves as the connecting link between the
piston pin and the crankpin.

A

master rod

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49
Q

are attached to the
master rod by knuckle pins, which are pressed into holes
in the master rod flanges during assembly.

A

articulated rods

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50
Q

is used
primarily in V-type engines.

A

fork-and-blade rod assembly

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51
Q

___ of a reciprocating engine is a
cylindrical member which moves back and forth
within a steel cylinder.

A

piston

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52
Q

top of the piston, or head, may be

A

flat, convex, or concave.

53
Q

prevent leakage of gas pressure from the combustion chamber and reduce to a
minimum the seepage of oil into the combustion chamber.

A

piston rings

54
Q

is most often used in making piston rings.

A

Gray cast iron

55
Q

is to prevent the escape of combustion gases past the piston during
engine operation.

A

compression rings

56
Q

are placed in the grooves immediately below the compression rings and above the
piston pin bores.

A

Oil control rings

57
Q

usually has a beveled face and is installed in the groove at the bottom of the
piston skirt.

A

oil scraper ring

58
Q

The portion of the engine in which the power is developed
is called the

A

cylinder.

59
Q

Each cylinder is an
assembly of two major parts:

A

cylinder head and
cylinder barrel.

60
Q

is to provide a place for combustion of the fuel/air mixture and to give
the cylinder more heat conductivity for adequate cooling

A

cylinder head

61
Q

Aluminum alloy is used in the construction for a number of reasons:

A
  • It is well adapted for casting or for the machining of deep;
  • closely spaced fins;
  • it is more resistant than most metals to the corrosive attack of tetraethyl lead in gasoline.
62
Q

is made of a
steel alloy forging with the inner surface hardened to resist wear of the piston and the piston rings which
bear against it.

A

cylinder barrel

63
Q

The steel soaks up nitrogen from the gas, which forms iron nitrides on the exposed
surface. As a result of this process, the metal is said to be

A

nitrided.

64
Q

This is a process that plates chromium on the
surface of the cylinder barrel and brings it back to new standard dimensions.

A

chroming.

65
Q

The fuel/air mixture enters the cylinders
through the intake __ ports, and
burned gases are expelled through the
exhaust ___ ports.

A

valve

66
Q

The valves used in aircraft engines
are the

A

conventional poppet type

67
Q

acts as a pilot
for the valve head and rides in
the valve guide installed in
the cylinder head for this
purpose.

A

valve stem

68
Q

consists of a cam ring or camshaft equipped with lobes that work against
a cam roller or a cam follower

A

the valve operating mechanism

69
Q

The valve mechanism of a radial engine is operated by one or two
___, depending upon the number of rows of cylinders

A

cam rings

70
Q

The valve mechanism of an
opposed engine is operated by a

A

camshaft

71
Q

The function of the tappet assembly

A

is to convert the rotational
movement of the cam 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.

72
Q

The tappet assembly consists of:

A

A cylindrical tappet,
A tappet roller
A tappet ball socket or push rod socket;
and
4. A tappet spring

73
Q

, which slides in and
out in a tappet guide installed in one of
the crankcase sections around the cam
ring;

A

A cylindrical tappet

74
Q

, which follows the contour
of the cam ring and lobes;

A

tappet roller

75
Q

require the valve clearance to be adjusted manually by
adjusting a screw and lock nut.

A

Solid lifters or cam followers generally

76
Q

Some aircraft engines incorporate hydraulic tappets that automatically keep the valve clearance at zero,
eliminating the necessity for any valve clearance adjustment mechanism.

A

Hydraulic Valve Tappets/Lifters

77
Q

, tubular in form, transmits the lifting force from the valve tappet to the rocker arm. A
hardened-steel ball is pressed over or into each end of the tube.

A

push rod

78
Q

transmit the lifting force from the cams to the valves. Rocker arm assemblies are
supported by a plain, roller, or ball bearing, or a combination of these, which serves as a pivot.

A

rocker arms

79
Q

are to close the valve and to hold the valve securely on the valve seat.

A

valve springs

80
Q

is any surface which supports, or is supported by, another surface.

A

bearing

81
Q

are generally used for the crankshaft, cam
ring, camshaft, connecting rods, and the accessory drive
shaft bearings.

A

Plain bearings

82
Q

consists of grooved
inner and outer races, one or more sets of balls, in
bearings designed for disassembly, and a bearing
retainer

A

A ball bearing assembly

83
Q

are made in many types and
shapes, but the two types generally used in the
aircraft engine are the straight roller and the
tapered roller bearings

A

Roller bearings

84
Q

The increased brake horsepower delivered by a high horsepower engine results partly from increased
crankshaft rpm.

A

Propeller Reduction Gearing

85
Q

s. Many
types of reduction gearing systems are in use. The three types most commonly used are

A

spur
planetary, bevel planetary, and spur and pinion.

86
Q

Propeller shafts may be of three major types:

A

tapered, splined, or flanged.

87
Q

common unit of mechanical power is the

A

horsepower

88
Q

is a comparison of the volume of space in a cylinder when the piston is at
the bottom of the stroke to the volume of space when the piston is at the top of the stroke.

A

compression ratio

89
Q

is the horsepower calculated from the indicated mean
effective pressure and the other factors which affect the power output of an engine.

A

indicated horsepower

90
Q

The power delivered to the propeller
for useful work is known as

A

brake horsepower (bhp).

91
Q

is a measure of load

A

Torque

92
Q

There are numerous devices for measuring torque, such as a

A

dynamometer or a torque meter

93
Q

is the indicated horsepower minus brake horsepower.

A

Friction horsepower

94
Q

is the average pressure produced in the
combustion chamber during the operating cycle and is an expression of the theoretical, frictionless power
known as indicated horsepower.

A

indicated mean effective pressure (IMEP),

95
Q

The first power overcomes internal friction, and the
horsepower thus consumed is known as

A

friction
horsepower.

96
Q

The second power, known as ____
produces useful work at the propeller.

A

brake horsepower,

97
Q

That portion of IMEP that produces brake
horsepower is called

A

brake mean effective
pressure (BMEP).

98
Q

The remaining pressure used to overcome internal
friction is called

A

friction mean effective pressure
(FMEP).

99
Q

The ratio of useful work done by an engine to the heat energy of the fuel it uses, expressed in work or heat
units, is called the

A

thermal efficiency

100
Q

Reciprocating engines are only about ___ percent thermally efficient

A

34

101
Q

is the ratio that shows how much of the power developed by the expanding gases in
the cylinder is actually delivered to the output shaft.

A

Mechanical efficiency

102
Q

. It is a comparison of the volume of fuel/air
charge (corrected for temperature and pressure) inducted into the cylinders to the total piston displacement of
the engine.

A

Volumetric efficiency

103
Q

most common fuels are

A

AVGAS for reciprocating engines and Jet A for turbine engines.
AVGAS is generally either 80 (red) or 100LL (blue) octane.

104
Q

is a measure of a liquid’s tendency to vaporize under given conditions.

A

Volatility

105
Q

is a
com-plex blend of volatile hydrocarbon compounds that have a wide range of boiling points and
vapor pres-sures.

A

Gasoline

106
Q

three general causes of vapor lock are:

A
  • lowering of the pressure on the fuel;
  • high fuel temperatures;
  • and excessive fuel turbulence.
107
Q

When fuel
changes from liquid to vapor, it extracts heat from its
surroundings.

A

CARBURETOR ICING

108
Q

is the explosive, uncontrolled burning of the fuel-air charge.

A

Detonation

109
Q

is precisely timed in a properly func-tioning ignition system.

A

Combustion

110
Q

is caused by hot spots in the cylinder

A

Preignition

111
Q

The basic parts of a fuel system include .

A

tanks, boost pumps, lines, selector valves, strainers, engine-driven
pumps, and pressure gauges

112
Q

is a
passageway or tube in which there is a narrow portion called the throat.

A

Simple venturi

113
Q

To provide for engine operation under various loads and at different engine speeds, each
carburetor has six systems:

A
  1. Main metering
  2. Idling
  3. Accelerating
  4. Mixture control
  5. Idle cutoff
  6. Power enrichment or economizer
114
Q

supplies fuel to the engine at all speeds above idling. The fuel discharged
by this system is determined by the drop in pressure in the venturi throat.

A

main metering system

115
Q
  • separate system is necessary for idling because the main metering system can be erratic
    at very low engine speeds.
A

Idling system

116
Q

supplies extra fuel during sudden increases in engine power.

A

accelerating system

117
Q

determines the ratio of fuel to air in the mixture

A

mixture control system

118
Q

The carburetor has an ______so that the fuel can be shut off to stop the engine.

A

idle cutoff system

119
Q

automatically increases the richness of the mixture during high power
operation.

A

power enrichment system

120
Q

, the most common of all carburetor types, has several distinct disadvantages.

A

float-type carburetor

121
Q

essential subsystems of a float-type carburetor are:

A
  1. Float chamber mechanism system
  2. Main metering system
  3. Idling system
  4. Mixture control system
  5. Accelerating system
  6. Economizer system
122
Q

is provided between the fuel
supply and the main metering system of the
carburetor.

A

float chamber

123
Q

main metering system supplies fuel to
the engine at all speeds above idling and
consists of:

A
  1. Venturi
  2. Main metering jet
  3. Main discharge nozzle
  4. Passage leading to the idling system
  5. Throttle valve
124
Q

On float-type carburetors, two types of purely manual or cockpit controllable devices are in general use
for controlling fuel/air mixtures,

A

the needle type and the back-suction type.

125
Q

In this system, a certain amount of
venturi low pressure acts upon the fuel in the float chamber so that it opposes the low pressure existing at
the main discharge nozzle.

A

e back-suction-type

126
Q

is provided by a needle valve in the base of the float
chamber.

A

needle-type system

127
Q

When the throttle valve is opened quickly, a large volume of air rushes through the air passage of the
carburetor

A

Accelerating System

128
Q

For an engine to develop maximum power at full throttle, the fuel mixture must be richer than for
cruise.

A

Economizer System

129
Q
A

powerplant (1 decks)

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