RPL Engines and Systems Flashcards
1
Q
What is a cylinder?
A
A chamber in which fuel and air is burned
2
Q
What is a piston?
A
Helps to burn fuel and the motion of the piston drives the plane
3
Q
What is the purpose of piston rings?
A
Seals combustion chamber
Supporting heat transfer from piston to cylinder wall
Regulating engine oil consumption
4
Q
What do spark plugs do?
A
Ignites fuel air mixture in the cylinders
5
Q
What are the inlet/exhaust valves?
A
Inlet valves allow fuel and air into the cylinders and exhaust valves open to release burnt gases after combustion
6
Q
What is the purpose of mixture?
A
To mix fuel and air to a correct ratio in order for optimal efficiency of engine
7
Q
What is the result of perfectly mixed fuel?
A
No remaining fuel after burning
8
Q
What is the perfect fuel:air ratio?
A
15 air : 1 fuel
9
Q
What is the normal cruise mixture?
A
13 air : 1 fuel
10
Q
Whats the difference between richer mixture and leaner mixture?
A
Richer - more fuel/less air
Leaner - less fuel/more air
11
Q
At which air : fuel ratio will fuel not burn and what are other effects?
A
8 air : 1 fuel will not burn fuel and can also cause flooding and engine problems
12
Q
What happens during flight when the mixture is too lean?
A
EGT temperature will rise
13
Q
What are possible effects if mixture too rich?
A
Engine down on power
Carbon build up
Spark plug fouling
14
Q
What are the possible effects if the mixture is too lean?
A
Engine down on power (not enough fuel in cylinders_
Engine easily overheats
Detonation can occur
15
Q
What are the 4 engine strokes?
A
Intake (down)
Compression (up)
Power (down)
Exhaust (up)
16
Q
What happens on the intake stroke?
A
Inlet valve is open and exhaust valve is closed
Piston moves down barrel
Fuel and Air is drawn into combustion chamber
17
Q
What happens on the compression stroke?
A
Both valves are closed
Piston moves down
Fuel/Air is compressed
Temperature is increased
18
Q
What happens on the power stroke?
A
Both valves are open
Spark plug ignites the fuel/air mixture
Pressure of combustion forces piston down the barrel
19
Q
What happens on the exhaust stroke?
A
Final stroke
Piston is forced up the barrel
Gases produced are exited into the exhaust system
20
Q
What is the modified otto cycle?
A
Ignition and valve timing are adjusted to extract maximum output of the engine
21
Q
How are valve timings adjusted?
A
Camshafts
22
Q
What are the factors effecting engine output?
A
Quantity of gas in cylinders Temperature reached during combustion Position of throttle control Engine RPM Mixture condition Supercharging/Turbocharging
23
Q
What are the 2 types of abnormal combustion?
A
Detonation and pre-ignition
24
Q
What is detonation?
A
Occurs when fuel is too hot then ignited by spark plugs in which causes an explosion rather than a controlled burn
25
What are the primary causes of detonation?
Excessive air temperature
Over-lean mixture at high settings
Excessive manifold pressure
Overheated engine
26
What to do if detonation is suspected?
Richen mixture
Throttle back to reduce pressure in cylinders
Increase airspeed to reduce cylinder head temerpatures
27
What is pre ignition?
Ignition that commences before the spark from the plug in which is caused by a hot spot in cylinder
28
Primary causes of pre ignition?
Lead deposit
High power when mixture is too lean
Overheated spark plugs
29
What are the results from pre-ignition?
Rough running
Possible back fire
Rise in cylinder head temperature
Possible engine damage
30
What is the purpose of an ignition system?
To provide a correctly timed spark to the combustion chamber to ignite fuel/air mixture
31
How doe the ignition system work?
A high tension is generated and is made to jump the gap a the tip of a spark plug in which a low tension current cannot
32
What are the components of the ignition system?
Battery
Starter motor
Impulse Coupling
Magnetoss
33
What is the magneto ignition?
Magneto uses a permanent magnet to generate an electrical current in which is sufficient enough to jump across the spark plug gap
34
What is a magneto?
An electrical generator mounted on the rear of the engine
35
What are the advantages of a magneto ignition?
Spark cannot be produced where the crankshaft is not turning
| Magneto is independant of the remainder of the aircraft electrical system
36
What are the disadvantages of a magneto ignition?
Expensive
| Currents produced are weaker at low RPM such as engine start
37
How does dual ignition systems work?
Magneto of each ignition system supplies one of the two spark plugs per cylinder
38
What are the advantages of dual ignition systems?
Offer safety in the event of failure of one ignition system
| They result in more efficient fuel combustion when both are active
39
What is the ignition switch?
Allows ignition system to be turned off and the selection of either left or right magnetos only or both simultaneously
40
What is the impulse coupling?
The generation of high voltage at low rpm via a rapid turn of the magneto via tension enough to release a spring
41
What problem does impulse coupling solve?
Producing a strong enough spark to start up the engine whilst the magneto magnet is on idle or weak
42
What are spark plugs?
A conductor of electricity that accepts the high voltage from the magneto in which is utilised for the ignition of fuel/air mixture within the cylinder
43
What are some precautions of the magneto system?
Prolonged use of starter motor will drain battery and overheat the starter
Severely discharged battery can explode
Prolonged use of the starter motor could also cause it to overheat and possibly ignite
44
What should be done if the starter has been used for over 30 cumulative seconds?
Allow system to cool for several minutes
45
What happens if only a single magneto is selected?
Combustion efficiency is reduced in which will result in less power on regular throttle settings due to more time taken for a full combustion to occur
The opposite magneto is grounded
46
What happens if there is not a drop in RPM when a single magneto is selected?
Opposite magneto still supplies a spark or the opposite magneto was not working when both was selected
47
How can the ignition system be checked before take off?
Switch from both magnetos to L then return to both, note the rpm drop and regain, apply to R too
48
What are the typical figures for the magneto system?
Check both at 2000rpm
Max drop on a single magneto is 125rpm
Difference between L and R drop should not exceed 50rpm in difference
49
How could the ignition system still be live if the off position is selected?
Loose or broken wires or by swinging the propellor manually
50
What is a dead-cut?
Temporarily turning the magneto off to note a sudden loss in power then returning to both
51
What happens if the ignition is off but the engine continues to run?
The magneto system is not grounded and therefore still live
52
What is carburetor icing?
The build up of ice within the carburetor
53
What are the symptoms of carburetor icing?
Rough Running
| Power loss resulting in RPM drop
54
What is the solution to carburetor icing?
Activate carburetor heat
55
What happens when carburetor heat is activiated?
The hot air released creates a richer mixture due to the low air density and therefore result in less power and rpm
56
When should carburetor heat be used?
Unexplained drops in RPM
| Unexplained rough running
57
What would happen when the carburetor heat is activated whilst ice is present?
RPM would initially drop then would increase after the icing has melted
58
What is the components electrical system?
Lights
Avionics (Radio)
Some instruments
Flaps
59
What is the bus bar?
The main conductor and distribution centre of the electrical system in which the alternator and battery supply power into the bus bar
60
What does the battery do within the electrical system?
Provides initial electrical power to rotate engine
| Back up or emergency electrical power
61
What does the alternator do?
Powers the aircraft systems and recharges the battery after the engine has started in which its output is between 14-28 volts
62
What does the ammeter do?
An instrument that measures the amount of current flowing through the load
Monitor the performance of the aircraft electrical system
Shows if alternator/generator is producing adequate electricity
63
What does the centre zero ammeter indicate if the reading is in the negative and if it is in the positive?
Negative - Current is being drawn from the battery more than its being charged
Positive - The rate of charge of the battery
64
What does a full scale negative and positive indicate on the centre zero ammeter reveal?
Full scale negative - malfunction of alternator/generator
| Full scale positive - malfunction of regulator
65
What is the left zero ammeter?
Indicates only when the alternator is delivering a load
66
When will the ammeter read zero?
Battery on and engine off
| Engine on and alternator off
67
What should the left zero ammeter indicate when the battery is charged and the alternator is operating?
Slightly above zero reading
68
What would the left zero ammeter read if the electrical systems are turned on?
Ammeter reading would increase
69
What does it mean if the left zero ammeter drops to zero mid-flight?
Alternator failed
70
What is the purpose of the exhaust system?
Expel burnt hot gases from the cylinders into the atmosphere
Cabin heating
Carburetor heat for carburetor engines
71
What is the plenum chamber?
Where cold and hot air is mixed for cabin distribution
72
What are the disadvantages of the heating system?
A leak in the heat exhaust manifold can allow carbon monoxide to enter the cabin when heat is on
73
What are the colours of the carbon monoxide detector and what do they indicate?
Orange - normal conditions
| Black - carbon monoxide leakage
74
What should be done in a case of suspected carbon monoxide leak?
Cabin heat turned off
All possible sources of fresh air opened and oxygen to be used if possible
Land ASAP
75
What are some carbon monoxide poisoning symptoms?
Headache
Dizziness
Nausea
76
What is the purpose of the lubrication system?
Supply oil to the engine for the lubrication and cooling of all parts of the engine prone to heating via surface friction
77
What happens if oil is too cool or hot?
Cool - Thick and sticky in which may not flow through small engine clearances and therefore oil pressure rises
Hot - Thin and running in which oil pressure will drop
78
What is the oil sump?
Gathering of oil in a reservoir attached to the lower part of the engine after going through the engine
79
Identify and describe the 2 different oil sumps?
Wet Sump - engine where sump is attached to it in which most light aircraft use
Dry Sump - Has scavenge pumps that extracts oil from the sump and places it back to the external oil tank (utilised by aerobatic aircraft)
80
What are the components of the lubrication system?
```
Oil Pump
Oil filter
Bypass valve
Pressure relief valve
Oil cooler
Temperature gauge
Pressure gauge
Filler Cap
```
81
Why do aircrafts require the right additives?
To prevent foaming, undesirable carbon/sludge deposits and corrosion
82
What compound oil do aircraft engines use?
Asheless dispersant
83
What is oil viscosity?
Measures an oil's flow properties
High viscosity - Slow flow
Low viscosity - Faster flow
84
What do high and low oil levels indicate during pre-flight inspection?
Low - Inadequate lubrication that can lead into engine overheating
High - Excess oil to pass through piston rings into the combustion chamber in which means oil is burnt in the cylinders
Burnt oil is indicated by blue smoke out of the exhuast
85
Why is excessive heat in an aircraft engine undesirable?
Affects the way fuel/air burns
Weakens and reduces life of the engine parts
Impairs adequate lubrication
86
How much percent of heat energy released during combustion is actually useful?
25%
87
How is the engine temperature kept within acceptable limits?
Oil circulates within the engine
Expulsion of heat energy via exhaust
Air cooling circulates cool air
88
How are most modern aircraft engines cooled?
Cooled by the openings at the front of the engine cowling in which the air flows into the cylinders and around the engine via baffles
89
What is the purpose of engine baffles?
Reduces uneven cooling and prevents hot spots
90
When is air cooling least effective?
High power and low airspeed such as take off and go around
91
When should cowl flaps be open?
When taxiing
Take off
Climb
Cruise
92
What are the effects of high engine temperature?
```
Loss of power
Reduction of lubrication efficiency
Excessive oil consumption
Negatively affects fuel/air mixture
Causes detonation
Weaken engine components
```
93
How can high engine temperatures be avoided?
Open cowl flaps
Richen mixture
Reduce engine power
Increase airspeed
94
What is the purpose of the fuel system?
Provide fuel storage and the supply an adequate flow to the carburetor and fuel injection unit for operating conditions
95
What is the fuel system required to do?
Continuously provide fuel and positive fuel pressure during changes of altitude, attitude and sudden power changes
96
What are the components of the fuel system?
```
Fuel tanks
Fuel tank vents
Sumps/drains
Filters/strainers
Fuel pumps
Selector valve
Priming system
Gauges
```
97
What is the difference in fuel tanks in high and low wing aircraft?
Low wing - Fuel delivered to engine via fuel pump
| High wing - Fuel is gravity fed to the engine
98
When should the electric fuel pump be switched on?
Critical maneuvers such as take off, landing and low flying as will prevent fuel starvation if the mechanical fuel pump fails
99
How is priming achieved?
Manual priming pump
| Electric boost pump and the accelerator pump
100
How does priming work?
Sending fuel directly to the inlet manifold just before the cylinders
Bypassing the carburetor
101
What does the selector valve do?
Selects which tank the fuel is sourced from
102
Which fuel does a piston engine aircraft utilise?
AVGAS
103
What are the 2 grades of fuel used in Australia?
100/130 Green
| Low lead fuel 110LL Blue
104
Which fuel does jet engines use?
AVTUR (kerosine)
105
What are the most common causes of malfunction?
```
Fuel pump failure
Vapour locks
Blocked fuel tank vents
Incorrect grade fuel
Fuel contamination
```
106
How is the failure of an engine driven fuel pump indicated?
Zero fuel pressure on gauge
107
What should be done to restore fuel pressure?
Activate electric fuel pump and land as soon as practicable
108
What is the result of fuel vaporising in the wrong place?
Fuel starvation
109
How is fuel grade measured?
Combustion stability (anti-knock/anti-detonation) in which is indicated by octane rating
110
What does higher octane rating indicate?
Greater fuel stability and detonation resistance
111
What are possible effects of lower grade fuel?
Increased risk of detonation
Spark plug fouling
Corrosion of exhaust valve
112
What are the 3 primary contaminants of fuel in order of importance?
1) Water
2) Other petroleum products
3) Solid matter
113
How can fuel be checked for contamination?
By checking the fuel sump/drain with a tube before every flight
114
What is the purpose of the unusable fuel line?
For contaminants to sink down the bottom to be prevented from flowing into the engine and to be drained
115
What can be done to reduce contamination?
Fill tanks overnight to prevent condensation and water in the tanks
Make sure correct fuel is being used
Checking visually for water and particles
116
What are the refueling distance limits?
15m of exposed public building
9m of unsealed building
6m of stationary aircraft
5m of sealed building
117
What should be done if the fuelling equipment is immobile?
Aircraft to be placed where it can be rapidly be moved to a place of safety
118
What should a pilot in command do after fuelling is complete?
Fuel and oil tanks are securely refitted and a fuel drain is carried out
119
What happens if there is a fuel spill within 15m an aircraft?
Do not turn on or operate nearby aircraft
120
What should be done if a tachometer fails?
Use known power settings (half throttle = 2000rpm)
| Land as soon as practicable
121
What does the cylinder heat temperature indicate?
That the temperature of the hottest cylinder is within limits
122
What are the reasons for the CHT reading being too high?
```
Fuel/Air mixture too lean
Detonation/Pre-ignition
Too low airspeed at high power settings
Cowl flaps malfunctioning
Blocked cylinder cooling fins
```
123
What are the actions to be taken if the CHT reading is excessive?
```
Richen the mixture
Open cowl flaps
Reduce power
Increase airspeed
Land as soon as possible if CHT remains excessively high
```
124
What does the Exhaust Gas Temperature (EGT) indicate?
To source temperature readings for the best economy mixture
125
When does the oil temperature gauge measure oil temperature?
After oil passes through the oil cooler
126
What can abnormally high oil temperature be attributed to?
Low oil quality
Oil cooler blockage
Faulty temperature gauge
Incorrect oil type
127
What can be done when there is a high oil temperature reading?
Reduce power or increase airspeed (or both)
Richen mixture
Open cowl flaps
Land as soon as practible
128
When does the oil pressure gauge measure oil pressure?
After the oil comes out of the cooler and feeds into the engine parts
129
What does low oil pressure mean?
Insufficient oil pressure in the engine to maintain adequate lubrication
130
What are the factors/malfunctions that may lead to a lack of oil pressure?
Oil pump failure
Failed bearings
Leaking oil lines
Insufficient oil supply
131
What should be done if a faulty oil pressure gauge is suspected?
Check for oil temperature gauge, a normal reading usually means a faulty oil pressure gauge
Land as soon as practicable
132
What can be suspected from a sudden loss of oil pressure and a rise in oil temperature and what actions should be taken?
Engine failure
Reduce power
Land as soon as practicable
133
What does a complete loss of fuel pressure indicate and what actions should be taken?
Engine driven pump is inoperative
Switch on the boost pump
Land as soon as practicable
134
What does a gradual loss of fuel pressure indicate?
Blocked fuel vent
