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ATPL - [Mod 2] AGK - Engines > 09. Piston Engine Power, Efficiency and Control > Flashcards

09. Piston Engine Power, Efficiency and Control Flashcards

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1
Q

Power

The power of an engine is dicated by which 2 things in relation to the cylinders

A
  1. MASS - mass of charge into the cylinder
  2. TIMING - number of times per second mass of charge is put int

Pg 200

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2
Q

Power

On a fixed propeller engine, which instrument gives an indication of power being produced

A

RPM INDICATOR
(Tachometer)

Increased RPM roughly equates to an increased power for a given air density

Pg 201

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3
Q

Power

On a variable pitch propeller which 2 indicators should be monitored to gauge power

A
  1. RPM
  2. MAP

Resolution per minute
Manifold Absolute Pressure

Pg 201

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4
Q

Power

What is the dedicated guage for indicating power on a larger more sophisticated engine

This usually means Constant Speed Propeller Unit according to Padpilot

A

TORQUE GAUGE

Pg 202

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5
Q

GENERAL REVISION

Pressure
Length
Area
Number of cylinders
Engine power (proportional to RPM)

A

Pg 202

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6
Q

Power

What is the formula derived from Torque to determine power

A

POWER = TORQUE x RPM

T P R

Pg 202

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7
Q

Power

Where is torque measured

A

GEARBOX
Betwee engine and propeller

Pg 202

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8
Q

Efficiency

THe mechanical efficiency of a piston engine is never more than ____%

A

80%

This is the ratio of the actual power produced at the propeller shaft to the theoretical power

Pg 203

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9
Q

Efficiency

What is the greatest contributor to the loss of mechanical efficiency in a piston engine

A

POOR THERMAL EFFICIENCY

Thermal efficiency is the ratio of work done by the engine to the mechanical equivalent of the heat energy released by combusting fuel

Pg 203

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10
Q

Effiency

Thermal efficiency is expressed as a ratio of what to what

A

WORK DOWN to HEAT ENERGY

Thermal efficiency is the ratio of work done by the engine to the mechanical equivalent of the heat energy released by combusting fuel

Pg 203

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11
Q

Efficiency

Modern piston engines are around ____% thermally efficient

A

33%

Pg 203

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12
Q

Efficiency

As the compression ratio is increase, ____ is also increased

A

THERMAL EFFICIENCY

Pg 203

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13
Q

Efficiency

Thermal efficiency indcreases with what

A

INCREASED COMPRESSION RATIO

Pg 203

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14
Q

Efficiency

When the piston is at TDC, the tight space between the top of the piston and cylinder is known as what

A

CLEARANCE VOLUME

Pg 204

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15
Q

Efficiency

WHen the piston is at BDC, the larger space between the top of the piston and the cylinder is known as what

A

TOTAL VOLUME

Pg 204

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16
Q

Efficiency

What is the name given to the difference between the clearance volume and the total volume

A

SWEPT VOLUME

Pg 204

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17
Q

Efficiency

What is the swept volume derived from

A

CLEARANCE VOLUME and TOTAL VOLUME
Difference between

Pg 204

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18
Q

Efficiency

What does a HIGH compression ratio improve

A

THERMAL EFFICIENCY

Pg 204

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19
Q

Efficiency

What is the formula for working out displacement

A

Displacement = Piston area x stroke x no. of cylinders

Swept volume multipled by the numebr of cylinders gives displacement

Pg 205

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20
Q

Efficiency

The ____ volume multipled by ____ gives the displacement

A
  1. SWEPT
  2. No. of CYLINDERS

Pg 205

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21
Q

Efficiency

Modern aero engines have a relatively short stroke. A short stroke INCREASES or DECREASES the width of the engine

A

DECREASES

Pg 205

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22
Q

Efficiency

On a modern aero engine, what effect does a short stroke have on the engine

A

DECREASES OVERALL WIDTH

Pg 205

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23
Q

Efficiency

What is signfiicant about the connecting rods on a short stroke engine

A

SHORTER = LESS INERTIA

Pg 205

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24
Q

Efficiency

What is the less inertia created in a short stroke engine

A

SHORTED CONNECTING RODS

Pg 205

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25
# Efficiency In regards to the engine, what happens as a result of *shorted connecting rods*
MORE RESPONSIVE to RPM CHANGE ## Footnote Pg 205
26
# Efficiency How do aero engines compensate for *shorter strokes*
LARGE PISTON AREA ## Footnote Pg 205
27
# Efficiency What is the name given when the cylinder diameter equals the stroke
SQUARE or SQUARE CAGED ## Footnote Pg 205
28
# Effciency *Square* or *square caged* is the term given when what condition exists
CYLINDER DIAMETER equals the STROKE ## Footnote Pg 205
29
# Efficiency If a cylinder diameter *exceeds* the stroke, what name is given
OVER SQUARE ## Footnote Pg 205
30
# Efficiency *Over square* is a term used when what conditions exists
CYLINDER DIAMETER > stroke | Cylinder diameter is greater than stroke ## Footnote Pg 205
31
# Efficiency What is defined by the term *volumetric efficiency*
RATIO of **MASS** OF MIXTURE to **MASS** OF AIR introduced to the cylinder ## Footnote Pg 206
32
# Efficiency The ratio of *mass of mixture* to the *mass of air* introduced into the cylinder is known as what
VOLUMETRIC EFFICIENCY ## Footnote Pg 206
33
# Efficiency What happens as a result of *increased volumetric efficiency*
INCREASED ENGINE POWER ## Footnote Pg 206
34
# Efficiency What 3 factors influence volumetric efficiency in a *normally aspirated engine*
1. MIXTURE - ease mixture can enter cylinder 2. DENSITY - density of air (alt, temp, humidity) 3. EXHAUST - ease exhaust can leave cylinder ## Footnote Pg 206
35
# Efficiency Why does volumetric efficiency in a *normally aspirated engine* _increase_ with altitude (when MAP remains constant)
REDUCED AIR DENSITY ## Footnote Pg 206
36
# Efficiency Why does volumetric efficiency in a *normally aspirated engine* _increase_ with RPM
INCREASED MOMENTUM OF GASES ## Footnote Pg 206
37
# Efficiency Volumetric efficiency in *normally aspirated engines* increases under which 2 circumstances
1. ALTITUDE - increased altitude means reduced density (*ONLY* while MAP remains constant) 2. RPM - Increased momentum of the gases ## Footnote Pg 206
38
# Efficiency In a *normally aspirated engine* the maximum obtainable MAP will INCREASE or DECREASE with altitude. Why does this happen
1. DECREASE 2. REDUCING ATMOSPHERIC PRESSURE ## Footnote Pg 207
39
# Efficiency What will happen to the MAP as altitude increases and why
1. DECREASE 2. REDUCING ATMOSPHERIC PRESSURE ## Footnote Pg 207
40
# Efficiency Maximum power in a *normally aspirated engine* is obtained where in terms of altitude
LOW PRESSURE ALTITUDE ## Footnote Pg 207
41
# Efficiency What will happen to *power* as altitude *increases* in a normally aspirated engine
REDUCES ## Footnote Pg 207
42
# Efficiency On a normally aspirated engine with a variable pitch propeller, if the aircraft climbs at maximum *continuous power* (NOT MAX POWER!), ____ and ____ can be kept constant by using which 2 levers
1. MAP 2. RPM 3. THROTTLE & RPM ## Footnote If an aircraft is climbing intially at less than full power, for example at max continuous power, both MAP and RPM can be kept constant using the throttle and RPM levers. Pg 207
43
# Efficiency On a normally aspirated engine with a variable pitch propeller, if the aircraft climbs at maximum *continuous power* and MAP and RPM are kept constant, power would INCREASE or DECREASE with altitude until the throttle is ____ and MAP can no longer be obtained
1. INCREASE 2. OPENED ## Footnote Pg 207
44
# Control and handling Piston engine instrumentation *may* include which following instruments 1. RPM Gauge [ ] 2. MAP Gauge [ ] 3. Boost Pressure Gauge [ ] 4. Oil Pressure Gauge [ ] 5. Oil Temperature Gauge [ ] 6. CHT gauge [ ] 7. EGT Gauge [ ] 8. Fuel Pressure Gauge [ ] 9. Induction System Temperature Gauge [ ]
ALL CORRECT | 1, 2, 3, 4, 5, 6, 7, 8, 9 ## Footnote Pg 208
45
# Control and handling What does the *RPM gauge* measure
CRANKSHAFT RPM ## Footnote Pg 208
46
# Control and handling What does the *Manifold Absolute Pressure (MAP) gauge* measure and in what unit
MANIFOLD PRESSURE (Hg in) ## Footnote Pg 208
47
# Control and handling Where does the *oil pressure gauge* measure the oil pressure
AFTER PRESSURE FILTER | Pressure filter immediately after the pressure pump ## Footnote Pg 208
48
# Control and handling Where does the *oil temperature gauge* measure the oil temperature
OIL RETURN LINE ## Footnote Pg 208
49
# Control and handling Specifically, what does the *cylinder head temperature gauge (CHT)* measure
HOTTEST CYLINDER ## Footnote Pg 208
50
# Control and handling On a *carburettor engine*, what does the *fuel pressure gauge* measure
FUEL PUMP OUTPUT PRESSURE ## Footnote Pg 208
51
# Control and handling On a *fuel injected engine* what does the *fuel pressure gauge* measure
MINFOLD OUTPUT PRESSURE ## Footnote Pg 208
52
# Control and handling What does an *induction system temperature gauge* measure
TEMPERATURE at CARBURETTOR INLET ## Footnote Pg 208
53
# Control and handling Piston engine controls *may* include the following; 1. Throttle lever [ ] 2. RPM lever [ ] 3. Mixture control [ ] 4. Carburettor heat control [ ] 5. Alternate air [ ] 6. Cowl flap lever [ ] 7. Ignition switch [ ] 8. Engine priming pump [ ] 9. Engine prime switch [ ]
ALL CORRECT | 1, 2, 3, 4, 5, 6, 7, 8, 9 ## Footnote Pg 210
54
# Control and handling On a *fixed pitch* propeller, the throttle lever alters the position of what component to control MAP or engine RPM
BUTTERFLY VALVE ## Footnote Pg 210
55
# Control and handling What sort of engine uses an RPM lever, and what does it set the RPM on
1. CONSTANT SPEED ENGINE 2. ENGINE/PROPELLER RPM ## Footnote Pg 210
56
# Control and handling What does the *mixture control* adjust
FUEL FLOW from CARBUERETTOR ## Footnote Pg 210
57
# Control and handling What does the *carburettor heat control* select
HOT, UNFILTERED ALTERNATE AIR ## Footnote Pg 210
58
# Control and handling What sort of engine has an *alternate air* control, and why would this be used
1. INJECTED ENGINES 2. If FILTERED AIR becomes BLOCKED ## Footnote Pg 210
59
# Control and handling What is the purpose of adjusting the *cowl flap lever*
REGULATE CHT | ADjust position of cowl flap to introduce or remove cooling air to CHT ## Footnote Pg 210
60
# Control and handling What are 2 overriding principles of engine management that must be adopted for all types of engines
1. MINIMISE THERMAL STRESS 2. AVOID OVERBOOSTING ## Footnote Pg 212
61
# Control and handling What sort of system does the term *"Rev UP, Throttle BACK"* apply to
CONSTANT SPEED PROPELLER UNIT ## Footnote Pg 212
62
# Control and handling What is meant by the term *"Rev UP, Throttle BACK"*.
INCREASEING SPEED - (REV UP) - Increase RPM (rev) *_before_* Throttle (MAP) DECREASE SPEED - (THROTTLE BACK) - Decrease Throttle (MAP) *_before_* RPM (rev) | ON A CONSTANT SPEED PROPELLER UNIT ## Footnote Pg 212
63
# Control and handling Where are fuel drains situated on an aircraft and why
LOWEST POINT of fuel system WATER HEAVIER than fuel ## Footnote Pg 213
64
# Control and handling What are 2 reasons why starting an engine in cold temperatures is difficult when considering the fuel and electrical systems
1. FUEL VAPORISING - ability is reduced in the cold 2. BATTERY PERFORMANCE - reduced in cold ## Footnote Pg 213
65
# Control and handling Why should carb heat be avoided when the engine is running on the ground
UNFILTERED AIR | Risk of drawing particles up into the engine from the ground ## Footnote Pg 214
66
# Control and handling What is a risk of prolonged idling of the engine in regards to spark plugs
EXCESSIVE FOULING ## Footnote Pg 214
67
# Control and handling What are the 2 power ratings that *some* high performance rated engines will have
1. TAKE-OFF POWER 2. MAX CONTINUOUS POWER ## Footnote Pg 214
68
# Control and handling On *some* high performance rated engines, there are 2 power modes, *Take-off* and *max continuous power*. What is the main difference between the 2 in regards to time and when should each be used
_TAKE OFF POWER_ Time limited Used for take-off and go around _MAX CONTINUOUS POWER_ **NOT** time limited Used for prolonged climb ## Footnote Pg 214
69
# Control and handling When changing power settings, how should the throttle lever be operated
SLOWLY and SMOOTHLY | Reduce stress on the engine ## Footnote Pg 214
70
# Control and handling What power setting should the engine be set to as soon as possible after take-off
MAX CONTINUOUS POWER ## Footnote Pg 214
71
# Control and handling How can *thermal shock* be avoided on engine shut-down
RUN ON LOW RPM | Run engine on low RPM for a few minutes to be allowed to cool ## Footnote Pg 214
72
# Control and handling 1. What can excessively *weak* mixture cause to the cylinder heads. 2. What does this increase the risk of
1. EXCESSIVELY HOT CHT 2. DETONATION ## Footnote Pg 215
73
# Control and handling What 4 things could cause rough running in a SEP engine | I See Moist Fuel
1. ICING - carb icing 2. COMPRESSION - uneven compression in cylinder 3. MOISTURE - in the ignition circuit 4. FUEL - issues with fuel delivery ## Footnote Pg 215
74
# Control and handling 1. What does *black smoke* in the exhaust indicate 2. *Black smoke* in the exhaust immediately after engine start may indicate what
1. EXCESSIVELY RICH MIXTURE 2. OVER PRIMING or UNLOCKED PRIMER PUMP ## Footnote Pg 215
75
# Control and handling 1. *Blue smoke* in the exhaust is caused by what 2. This may indicate what problem
1. OIL BURNING 2. WORN or BROKEN PISTON RINGS ## Footnote Pg 215
76
# Control and handling A *HIGH* or *LOW* CHT may indicate cowl flaps being left *closed*
HIGH ## Footnote Pg 215
77
# Control and handling If the cowl flaps are left closed during ground running and taxing, what might likely be a probable result
EXCESSIVE CHT ## Footnote Pg 215
78
# Control and handling What is the technique to attempt to extinguish a carburettor fire as a result of excessive priming
CRANK THE ENGINE | This should ingest all the excess fuel into the engine ## Footnote Pg 215
79
# Control and handling What does FADEC stand for
**F**ull **A**uthority **D**igital **E**ngine **C**ontrol ## Footnote Pg 216
80
# Control and handling A FADEC monitors multiple parameters. It is able to adjust fule flow to injectors. To achieve this, specifically what 4 things will it be monitoring to make these adjustments
1. AIR - Temperature and pressure 2. THROTTLE - lever angle 3. ENGINE - Internal conditions ## Footnote Pg 216
81
# Control and handling a FADEC controls fuel and air ratio. This means that there is no need for what control by the pilot
MIXTURE CONTROL ## Footnote Pg 216
82
# Control and handling A FADEC system is critical to engine control and therefore must be provided with what
REDUNDANCY ## Footnote Pg 216
83
On a modern FADEC system, to provide electrically isolated channels, each channel has a dedicated what
PERMANENT MAGNET ALTERNATOR (PMG) ## Footnote Pg 216
84
# summary Power increasaes with increased ____. This is the ratio of ____ mixture to mixture at ____.
1. VOLUMETRIC EFFICIENCY 2. COMPRESSED 3. AMBIENT TEMPERATURE ## Footnote Summary

ATPL - [Mod 2] AGK - Engines (23 decks)

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