Aircraft Systems 1 Flashcards
Engines provide ____ to overcome DRAG.
THRUST
Piston engines run through the ___ cycle.
OTTO
Gas turbine engines run through the ______ cycle.
BRAYTON
Describe the parts in a standard piston engine cycle.
Inlet Valve
Piston
Crankshaft
Connecting Rod
Spark Plug
Outlet Valve
Describe the 4 stages of the piston (Otto) cycle.
Induction - Air drawn into cylinder through inlet valve.
Compression - Upward movement of piston compresses air.
Power - Spark used to ignite air/fuel mixture driving piston.
Exhaust - Hot gases expelled through outlet valve.
List the 5 different cylinder layouts
In-line
Inverted
Flat Opposed
V
Radial
2 main limitations of a piston engine
RPM
Temperature
List the types of gas turbines
Turbojet
Turbofan
Turboprop
Turboshaft
Describe the gas turbine work ‘cycle’
Intake - Air drawn into compressor
Compression - Inc T+P, dec Vol.
Combustion - Fuel injected and burned. Inc T+Vol.
Turbine - Work taken out of combustion gases to drive compressor.
Exhaust - Expelled from rear of turbine (possibly giving thrust).
List the sections in a Gas Turbine
Air Inlet
Compression
Combustion Chamber
Turbine
Exhaust
What sections make up the ‘Cold Section’ of a Gas Turbine?
Air Inlet
Compression
What sections make up the ‘Hot Section’ of a Gas Turbine?
Combustion Chamber
Turbine
Exhaust
In a turbojet, what proportion of the air goes into the combustion process?
100%
In an ‘optimal’ gas turbine the exhaust pressure is as close to ____ ______ to maximise energy efficiency.
INLET PRESSURE
Name the 2 types of air intake
Sub-sonic
Super-sonic
Name the 2 types of compressors
Axial
Centrifugal
Which type of compressor is “cheaper to produce”?
Centrifugal
Which type of compressor is “more difficult to manufacture”?
Axial
Which type of compressor has “lower maintenance and running costs”?
Centrifugal
Which type of compressor has “small mass flow rates”?
Centrifugal
Which type of compressor has a “large frontal area”?
Centrifugal
Which type of compressor has a “low compression ratio”?
Centrifugal
Which type of compressor has “higher maintenance and running costs”?
Axial
Which type of compressor is “multi stage”?
Axial
Which type of compressor has “air flowing radially”?
Centrifugal
Which type of compressor is “more expensive to produce”?
Axial
Which type of compressor is “single stage”?
Centrifugal
Which type of compressor has a “small frontal area”?
Axial
Which type of compressor has a “high compression ratio”?
Axial
Which type of compressor has “large mass flow rates”?
Axial
List the types of Combustion Chambers.
Multiple
Can-Annular
Annular
What is Turbine Creep?
Turbine blades lengthen under load and high temps.
What is Thermal Stress?
Rapid changes in temp causes uneven expansion and contraction in a turbine blade which increases the stress in the blade.
Advantage of a Turbofan
Increased thrust at low speeds results in better take-off performance.
Describe a Turbofan
Most common derivative of gas turbine
Has “By-pass”
In a Turboprop. The _____ absorbs the majority of the gas energy to drive the propeller
TURBINE
Advantage of a Turboprop
Less kinetic energy waste makes this the most efficient use of a gas turbine at low/medium altitudes and speeds up to 350 kt.
Advantage of a Turboshaft
More compact than the others.
Used on rotary assets
What gas turbines are designed for SUPERSONIC flight
Turbojet
What gas turbine is most efficient at low speeds?
Turboprop
A compressor stall occurs when a compressor operates _____ __ ___ ______.
Outside of its limits
List some causes of a compressor stall
Wrong RAF over comp blades.
A blade ‘stalls’.
All comp blades in stage at same angle/RAF.
Presented airflow is disrupted.
Disrupted airflow can cause following stages to stall.
What are the indications of a compressor stall?
Increase in engine vibration.
Increase in Turbine Gas Temp (TGT).
Describe a compressor surge
Not a high enough pressure in the compressor therefore flame will migrate through compressor and force flame out front.
Indications of compressor surge
Intake banging
Large rise in Turbine Gas Temp (TGT)
Loss of thrust
Possible catastrophic compressor failure
A STALL is a ____ breakdown of airflow through the compressor.
PARTIAL
A SURGE is a ____ breakdown of airflow through the compressor.
COMPLETE
What design features can help prevent comp stalls and surging.
Variable inlet guide/ stator vanes
Multi-spool compressors
Compressor bleeds
What are the 9 uses of oil in an aircraft?
Reduce friction
Reduce wear
Cleaning
Minimise corrosion
Cooling
Heating (fuel heat exchanger)
Hydraulic Fluid
Chip detection
Engine status (Oil T+P)
Fluid introduced between two load bearing surfaces is known as _____
LUBRICATION
What is hydrodynamic lubrication regime?
Relatively thick layer of oil between surfaces
What are the 3 lubrication regimes?
Hydrodynamic
Boundary
Mixed
What is Boundary layer lubrication?
Very thin layer of oil between surfaces.
Often seen during start up conditions.
Components of the Engine Oil system (6)
Oil Tank
Oil Pump
Oil Cooler
Filter Assembly
Magnetic Chip detection
Monitoring Instruments
What are the 2 key parameters we want to know about the engine oil system?
Temp and Pressure
Components of the Fuel system (7)
LP fuel cock
Fuel cooled oil cooler
Fuel filter
HP fuel pump
Throttle valve
Fuel control unit
HP shut-off valve
Everything upstream (before) the HP fuel pump is known as the ______ pressure part of the system
LOW pressure
Everything downstream (after) and inc. the HP fuel pump is known as the ______ pressure part of the system
HIGH pressure
List some uses of the air from the Air system
Engine cooling
Blade cooling
Air sealing
Bleed air
Anti-icing
Why is engine cooling required?
Internal temperatures are very high
What is used to cool the engine?
Combination of Air and Oil
Which blades typically require the most amount of cooling?
Turbine blades
How are blades in the engine cooled?
Through longitudinal holes in the internals of the blade structure
Film cooling on leading and trailing edges of the blades
What info/data about the engine is typically provided to the pilots?
Eng Temp
Eng Speed
Torque
Fuel Flow, T+P
Oil T+P
Bleed air can be used for
Airframe anti-icing
Cabin pressurisation
Fuel tank pressurisation
Pneumatic Services
Air blown flight controls
Anti-icing air can be supplied to
Engine intakes
Inlet guide vanes
Inlet cone
Engine temperature is measured using ______
THERMOCOUPLES
What piece of equipment is used to measure engine speed?
Tacho-Generator
List some accessory systems driven by the gearbox (9)
Fuel Control Unit (FCU)
HP Fuel Pump
LP Fuel Pump
Oil Pumps
Scavenger Pumps
Centrifugal breather
Tacho-generator
DC starter/generator
Air Con Compressor
The frequency of the Tacho-Generator is ______ proportional to the speed of the engine.
DIRECTLY
Torque is measured by the ________
TORQUEMETER
Name the 4 types of fuel
AVGAS
AVTUR
AVTAG
AVCAT
What 3 fuels include FSII?
AVTUR
AVTAG
AVCAT
Piston Engines use what fuel?
AVGAS
Turbine engines use what fuel?
AVTUR
At extreme low temps what fuel is used?
AVTAG
Naval aviation uses what type of fuel?
AVCAT
AVTAG is known as _____ fuel
“WIDE CUT”
List the 7 key terms associated with fuel
Density
Specific Gravity
Freezing point
Fuel System Icing Indicator (FSII)
Flash Point
Volatility
Viscosity
What is the FLASH POINT of a fuel?
Lowest temperature at which fuel begins to form combustible vapour
5 key properties of AVGAS
Anti-knock value
Volatility
Vapour locking tendency
Stability
Solvent and corrosion properties
7 key properties of AVTUR
Ease of flow under operating conditions
Quick start of engines
Complete combustion under ALL conditions
High calorific value
Non-corrosive
Minimal fire hazard
Lubrication of moving parts
The LP fuel cock _____ fuel from getting to the engine.
PREVENTS
The LP fuel pump is housed in the _______ ____
COLLECTOR TANK
The symbol for the jet pump is ….
two funnels + circle with internal cross
The symbol for the LP fuel pump is …
one funnel (at 12 oclock) of circle with internal cross
What devices are used to prevent the engine of an aerobatic aircraft being starved of fuel during aerobatic maneuvres?
Recuperator Tank
Double Entry LP fuel pump
Flop tube
The X-FEED cock allows ____ engine to be fed by ___ fuel tank
ANY engine
ANY tank
The FUEL TRANSFER cock allows fuel tanks to be ______
REBALANCE/ EQUALIZED
If the FUEL FILTER is blocked. Will this stop the engine from operating?
No. There is the bypass valve.
What is used to get rid of fuel?
Fuel Jettison
What are the 3 typical warnings associated with fuel?
Low Level
Pressure
Filter
Fire protection is made up of two independent systems. These are
Fire and Overheat detection
Fire extinguishing
The 3 most common sources of fire are
Fuel leaks in vicinity of hot equipment.
Hot gas leaks, from engines or ducting, impairing on inflammable materials.
Electrical or mech malfunctions in equipment
Symptoms of HALON poisoning
Itchy Throat
- Streaming eyes
The function of the fire detection systems are to
Monitor designated areas for rise in temp
Provide warning to the crew
Complete electrical circuits to allow crews to activate safety measures
Thermal switches are placed in areas of the a/c where a ____ may arise
FIRE
____ ____ is made of Stainless Tube, Filling Material and Central Electrode.
FIRE WIRE (CONTINUOUS ELEMENT)
The FIRE BOTTLE system is what is known as a _ ___ system
2 SHOT
HALON fire extinguishers turn the fire triangle into a ___ ______, adding a 4th side by interrupting the ______ of a fire
FIRE TETRAHEDRON, adding a 4th side by interrupting the combustion of a fire
Name the 3 different Ice Detection Devices
Visual Ice Detector
Differential static pressure Ice Detector
Frequency monitor Ice Detector
Where does bleed air get drawn from within the engine to feed the ice protection system?
COMPRESSOR
When you select the bleed air, will the engine become hotter or colder?
Hotter as the engine will be working harder
List areas on the A/C which are sensitive to ice formation
Aerofoil surfaces
Engine Intakes
Engine Internal Surfaces
Rotor blades and propellers
Windscreens
Control hinges and linkages
Instrumentation probes and vanes
Weapons and weapons carriers
Ice causes _____ to DECREASE because the engine will not perform as efficiently.
THRUST
Ice causes _____ to DECREASE because the shape of the wing changes with the build up of ice.
LIFT
Ice causes _____ to INCREASE because of the build up of ice disrupting the airflow across the wing, body and tail.
DRAG
Ice causes _____ to INCREASE because the ice adds to the overall mass of the aircraft.
WEIGHT
Ice protection system fall into 2 categories. These are:
ACTIVE
or
PASSIVE
Active Ice Protection is made up of ______
Anti-icing
De-icing
List some methods of alerting crew to the risk of ice formation
Met forecasts
External visible checks
Ice accretion probes
Flood lights
Alerts and automatic systems
Describe the “Visual Ice Detector”
HEATED AEROFOIL ROD
INSPECTION LAMP - For operating in darkness
Describe the “Differential static pressure Ice Detector”
Has a SERIES OF HOLES MEASURING PRESSURE.
System monitors the pressure difference along the probe.
Describe the “Frequency monitor Ice Detector”
Measured using a VIBRATING ROD
Utilises changes in the resonant freq of the probe which occurs with ice formation.
Engine anti-icing systems are an integral part of the engine and are _________ of the airframe anti-icing.
INDEPENDENT
How are windscreens protected against icing?
ELECTRICALLY HEATED WINDSCREEN
Ice, Snow and Slush deposits ____ be _____ prior to flight, by the ground crew.
MUST be REMOVED
Only following the removal of Ice, Snow and Slush deposits, should ______ _____ de-icing be applied.
CHEMICAL FLUID
Factors to be considered in the design of an aircraft are:
Stress
Strain
Stiffness
Design Limit Load (DLL)
Temperature
Corrosion
Natural/Environmental Hazards
Define Stress, Strain and Stiffness
Stress - Load per unit area of x-section
Strain - Deformation caused by stress
Stiffness - Ratio of stress over strain
What are the ideal properties of the materials used in aircraft construction? (4)
High strength and stiffness
Lightness
Low cost
Ease of construction and production
List some of the different materials used in aircraft construction
Aluminium alloys
Titanium alloys
Magnesium alloys (rarely used)
Steel
Carbon Fibre Comp. (CFCs)
Glass Reinforced Plastic (GRP)
Wood
Name the 3 different types of fuselage
Truss
Monocoque
Semi-monocoque
List some components in the mechanical structure of the fuselage
Bulkhead
Stringers
Longerons
Vert/Diag Web Members
Frames
Skin (Semi-Mono) / Stressed Skin(Mono)
List some components in the mechanical structure of the wing
Stringer
Spar (Front/Rear)
Skin
Ribs
Honeycomb Sandwich Core
Wing loading forces are carried by the ….. (4)
Spars
Stringers
Ribs
Skin
List the 3 different wing configurations
inc. some benefits of each
High wing - Ease of cargo loading
Mid-wing - Small radar cross section in modern ‘stealth’ a/c
Low wing - shorter undercarriage, crash protection
What does the word ‘EMPENNAGE’ refer to?
TAIL SECTION of an aircraft
List the types of EMPENNAGE (5)
Tailplane and Fin (Prefect)
All Flying Tailplane (C17/A400)
Taileron (Tornado)
Tailless (Vulcan)
V tail (MQ-9 Reaper/Protector)
The forward flight controls of the Typhoon are known as _____
CANARDS
List some key design features influencing design of combat a/c
Powerplant
Fuel and weapon carriage
Undercarriage stowage
Low-frontal area and x-section
Stealth technology
List some key design features influencing design of transport a/c
Cabin length
Cabin width
Freight Vol
Passenger and Weight distribution to maintain COG
Definition of stress
Load per unit area
Definition of strain
Deformation caused by stress
Definition of Stiffness
Ratio of stress over strain
Definition of DLL
Maximum load the designer would expect airframe to experience in service.
Ideal properties of aircraft materials
High Strength and Stiffness
Lightness
Low cost
Ease of construction and production
3 types of fuselage
Truss
Monocoque
Semi-monocoque
5 parts that make up the wing structure
R___
F___ S___
R___ S___
S___
S______
Ribs
Front Spar
Rear Spar
Skin
Stringer
Another name for tail section
EMPENNAGE
5 configs of tailplanes
S______
A___ F______ T______
T______
T______
V _____
Standard
All Flying Tailplane
Taileron
Tailless
V Tail
Key points of each tailplane type
Standard.
All Flying Tailplane. - Servo tabs used to aid in effective control of a/c trimming
Taileron. Operate ind. providing pitch and roll.
Tailless. Make use of ELEVONS.
V Tail. V and H components producing pitch and yaw.
3 axis of an aircraft
Longitudinal
Lateral
Normal
3 axis of an aircraft
Longitudinal
Lateral
Normal
Types of Icing detection
Differential
Visual
Frequency
Engine anti-icing and airframe anti-icing systems operate i________ of each other
INDEPENDENTLY
Only following the removal of Ice, Snow and Slush deposits, should ______ _____ de-icing be applied.
CHEMICAL FLUID
Windshields are e_______ h_____ to prevent ice build up.
ELECTRICALLY HEATED
In addition to FIRE, the fire detection system can detect H___ and S____
FIRE, HEAT and SMOKE
What is a 2 shot system?
2 separate cylinders
Independent but crossed linked
Where would you locate thermal switches in the aircraft?
As close to areas that have potential to produce fires.
____ ____ is made of Stainless Tube, Filling Material and Central Electrode.
FIRE WIRE
The two overarching systems associated with fire are…
Fire Detection
Fire Extinguishing
The 3 most common sources of fire are
Fuel leaks in vicinity of hot equipment.
Hot gas leaks, from engines or ducting, impairing on inflammable materials.
Electrical or mech malfunctions in equipment
Most common fuel on gas engines
AVTUR
What does FSII stand for and what does it protect against?
Fuel System Icing Inhibitor
Protects against icing and fuel fungus
Which fuel can be described as Wide Cut?
AVTAG
When do we use AVTAG ‘Wide Cut’ fuel?
Cold/Polar
AVTAG is a mix of ____ and ____
AVTUR and AVGAS
What is the purpose of the LP fuel cock?
Prevents fuel getting to the engine
Name 8 components that can form part of an airframe LP fuel system
Fuel tanks
Fuel pumps
LP cocks
Transfer valves
X-feed valves
Jet pumps
Dump valves
Recuperator tank
What parameters can be displayed in the fuel instrumentation?
Pressure
Flow
Temp
Quantity
De-totalizer
What fuel is used on aircraft carriers?
AVCAT
What 2 fuels make up AVCAT?
AVTUR and Diesel
Why do we mix AVTUR and diesel in AVCAT?
Les volatile higher flashpoint
What is the function of the x-feed valve?
Allow any tank to feed any engine
What transformation does AVTUR go through as it starts to freeze?
It turns to waxy crystals
What is the name of the valve that we use to move fuel from one tank to another?
Fuel transfer valve
What is the definition of ‘Flashpoint’?
The lowest temp at which the fuel will start to produce a combustible vapour
If 160kg/0.8 SG = 200 ltrs
How many litres would be required to give a 140kg fuel uplift?
140kg /0.8 = 175 ltrs
What are the fuel supply options available to ensure engines can continue to operate during aerobatic manoeuvres?
Recuperator Tank
Double Entry LP fuel pump
Flop tube
Which fuel is used on Piston engine aircraft and whatdoes 100LL refer to ?
AVGAS
100 Low Lead
Describe the gas turbine work ‘cycle’
Intake - Air drawn into compressor
Compression - Inc T+P, dec Vol.
Combustion - Fuel injected and burned. Inc T+Vol.
Turbine - Work taken out of combustion gases to drive compressor.
Exhaust - Expelled from rear of turbine (possibly giving thrust).
How would you describe an axial flow compression?
Expensive
Small frontal area
Large mass flowrates of air
High compression ratio
Multi-stage
What is the purpose of the turbine in a turbine fan for?
There to extract the maximum amount of energy from the combusted gases.
What do we use the oil system for?
Reduce friction
Reduce wear
Cleaning
Minimise corrosion
Cooling
Heating (fuel heat exchanger)
Hydraulic Fluid
Chip detection
Engine status (Oil T+P)
What are the 3 lubrication regimes?
Hydrodynamic
Boundary
Mixed
3 key components of the HP side of the fuel system.
HP fuel cock
HP fuel pump
HP FCU (fuel control unit)
What is one of the most popular things bleed air is used for?
Pressurisation and cabin conditioning (heating)
A filter is used to remove d____
DEBRIS
Turboprop the m_____ of energy is absorbed by the turbines
MAJORITY
A COMPLETE breakdown of air flow through the compressor is known as a s___.
SURGE
A PARTIAL breakdown of air flow through the compressor is known as a s___.
STALL
A Tacho-Generator measures ….
ENGINE SPEED
Purpose of an Oil Tank is to …
HOLD/STORE oil
