Dale Crane Q's Flashcards
The pressure of moving gas is a measure of ______ energy (potential or kinetic)
potential
The velocity of moving gas is a measure of its ________ energy (potential or kinetic)
kinetic
Force is a vector quantity that has both ______ and _____
direction
magnitude
Work is the product of _______ and ______
force
distance
Power is the rate at which _____ is done
work
The rate at which an object is travelling in a given direction is the _______ (speed or velocity) of the object
velocity
Bernoulli’s principle explains that if energy is neither added to nor taken from a body of moving fluid, any increase in its velocity will result in a corresponding ________ (increase or decrease) in its pressure
decrease
When air flows through a converging nozzle at a subsonic speed, its velocity will ________ and its pressure will ________
(increase or decrease)
When air flows through a converging nozzle at a subsonic speed, its velocity will increase and its pressure will decrease
When air flows through a converging nozzle at a supersonic speed, its velocity will _______ and its pressure will ______
(increase or decrease)
When air flows through a converging nozzle at a supersonic speed, its velocity will decrease and its pressure will increase
When air flows through a diverging nozzle at a subsonic speed, its velocity will _______ and its pressure will _______
(increase or decrease)
When air flows through a diverging nozzle at a subsonic speed, its velocity will decrease and its pressure will increase
When air flows through a diverging nozzle at a supersonic speed, its velocity will _______ and its pressure will _______
(increase or decrease)
When air flows through a diverging nozzle at a supersonic speed, its velocity will increase and its pressure will decrease
An exhaust nozzle that prevents gases from flowing through it faster than the speed of sound is said to be a ______ nozzle
choked
The function of the turbine in a turbojet engine is to drive the ______
compressor
The six basic components in a turbojet engine are the:
- Air intake
- compressor
- diffuser
- combustor or burners
- turbine
- Tailpipe and jet nozzle
The portion of a turboprop engine that produces the hot gases that drive the turbines is called the _____ engine
core
A turboprop engine that uses a separate turbine to drive the propeller reduction gearing is called a/an ______ engine
free-turbine
A gas turbine engine used to drive the transmission of a helicopter is called a/an _____ engine
turboshaft
Three advantages of a turbofan engine over a turbojet engine are:
- Increased propulsion efficiency (fuel burn to useful thrust)
- lower noise level
- lower specific fuel consumption ( amount of fuel burned in one hour to produce one unit of thrust)
The ratio of the amount of air that passes through the fan to the amount of air that flows through the core engine is called the _____ ratio of the engine
bypass
The thermodynamic cycle of a gas turbine engine is the ______ cycle
Brayton
The Brayton thermodynamic cycle is the constant ________ (pressure or volume) cycle
pressure
The thrust produced by a turbofan engine is the sum of the thrust produced by the _______ and that produced by the ______
core engine
fan
An increase in the airspeed, with all else remaining the same, will cause turbine engine thrust to ________
(increase or decrease)
decrease
An increase in temperature of the inlet air, with all else remaining the same, will cause turbine engine thrust to ________
(increase or decrease)
decrease
An increase in the pressure of the inlet air, with all else remaining the same, will cause turbine engine thrust to _________ (increase or decrease)
increase
An increase in altitude will cause turbine engine thrust to ________ (increase or decrease)
decrease
(density factor greater than low temp factor)
An efficient cruising altitude for a turbojet- or turbofan powered aircraft is near 36,000 feet.
Above this altitude, the thrust produced by the engine ________
(increases or drops off more rapidly)
drops off more rapidly
An increase in ram effect, with all else remaining the same, will cause turbine engine thrust to _______
(increase or decrease)
increase
The speed of the high-pressure compressor in a dual-compressor turbofan engine is called _______
(N1 or N2)
N2
A pressure identified as Pt2 is ________ (static or total) pressure measured at the __________ (compressor or turbine) ________ (inlet or outlet)
static
compressor
inlet
What is customer bleed air?
Air that is tapped off a turbine engine compressor and used for such airframe functions as air conditioning and pressurisation. (not engine related stuff)
What are inlet guide vanes?
Inlet guide vanes are a set of stator vanes in front of the first stage of compression in a gas turbine engine
The two sections into which a gas turbine can be divided are the ________ section and the _______ section
cold
hot
The inlet ducts are actually part of the _______ (airframe or engine)
airframe
Inlet ducts for turbine engines may be divided into two classifications according to the speed of the aircraft on which they are installed. These are:
- Subsonic
- Supersonic
Most subsonic inlet air ducts are _________ (convergent or divergent)
divergent
The airspeed at which the ram effect of the air flowing into a divergent inlet air duct causes the pressure at the front of the compressor to be the same as the ambient pressure is called the ________ speed
ram recovery
Supersonic inlet ducts are of the __________ type
(convergent, divergent, convergent-divergent)
convergent-divergent
When supersonic air flows through the convergent portion of a CD duct, its velocity ______
(increases or decreases)
decreases
When supersonic air flows through a CD inlet duct, its velocity at the compressor inlet is _________
(subsonic or supersonic)
subsonic
Energy added to the air by a compressor initially increases the ______ of the air
(pressure or velocity)
velocity
The velocity of the air passing through a compressor is a measure of its ________ energy
(kinetic or potential)
kinetic
The pressure of the air passing through a compressor is a measure of its ______ energy
(kinetic or potential)
potential
After passing through the compressor, the air flows through a diffuser, which converts some of the _______ energy into pressure energy
velocity / kinetic
Two types of compressors used in gas turbine engines are ______ and ______ compressors
centrifugal
axial flow
The three components of a centrifugal compressor are:
- Impeller
- Diffuser
- Manifold
The ducts in the (compressor) diffuser are _______
(convergent or divergent)
divergent
A centrifugal compressor that has vanes on both sides is called a/an ________ compressor
double-entry
A centrifugal compressor that has vanes on both sides is called a/an _______ compressor
double-entry
The stators used with an axial-flow compressor cause the air to _______ (speed up or slow down)
slow down
After the air leaves the compressor, it flows through a/an _____ before it enters the combustion area
diffuser
The overall compression ratio of an axial-flow compressor is _______ (higher or lower) than that of a centrifugal compressor
lower
The blades of an axial-flow compressor can stall if the angle of attack becomes too ______ (high or low)
high
Two variables that affect the angle of attack of a compressor rotor blade are:
- Compressor Rotational speed (RPM)
- Velocity of the air through the compressor
The direction of the air entering the first stage of an axial-flow compressor is changed by the __________ so that it enters at the correct angle
inlet guide vanes
Two design features that may be used to prevent or minimize compressor stalls are:
- Variable inlet guide vanes
- Interstage bleed valves
An axial-flow compressor that has two separate compressors, each driven by its own turbine, is called a/an ________ compressor
dual-spool
The rearmost compressor in a dual-spool engine is the ______-pressure compressor
(high or low)
high
The low-pressure compressor is called the _______ compressor
(N1 or N2)
N1
The ratio of the mass of air moved by the fan to the mass of air moved by the core engine is called the ________ of a turbofan engine
bypass ratio
The angle of the inlet guide vanes is variable on some engines. The angles are changed hydraulically by the ________
fuel control
The air that flows through the combustion section but is not used in the combustion process is used for _____
cooling
Three types of combustors
- Annular
- Can-annular
- Multiple-can
A combustion in which the air leaving the compressor makes a 180^ turn, flows through the combustor, and makes another 180^ turn before it flows through the turbine, is a/an _______ combustor
reverse-flow
The air used in the combustion process is called ________ air
primary
There are normally ________ (how many) igniters used to ignite the fuel-air mixture in a gas turbine engine
2
The fuel-air mixture in cans not having an ignitor is ignited by flames from the other cans that travel through _____________
flame propagation tubes
A combustion section that has individual cans, but in which the hot gases from all of the cans are collected before they go to the turbine, is called a/an ______ combustor
can-annular
When the length of an engine must be kept as short as possible, a/an _______ combustor can be used
reverse-flow
The greater portion of the energy released from the fuel in a turbojet engine is used _________ (for thrust or to drive the compressor)
to drive the compressor
Turboprop and turboshaft engines use additional stages of ______ to produce the shaft horsepower needed to drive the propeller or helicopter rotors
turbines
The type of turbine used in a gas turbine engine is the _________ type
(axial or radial inflow type)
axial
The stationary vanes in a turbine section are located in the airflow path _______ the turbine rotors
(before or after)
before
The component in the turbine section that directs hot gases from the combustion section into the turbine is the ringe of turbine ______ or _____
guide vanes or nozzles
When gases flowing through a turbine nozzle can no longer accelerate, the nozzle is said to be operating in a/an ______ condition
choked
The point in a gas turbine engine at which the temperature is the highest is the _________
turbine inlet
The turbine inlet guide vanes form a series of __________ nozzles (convergent or divergent_
convergent
Three things the turbine inlet guide vanes do to the air as it passes through them are:
- increase its velocity
- decrease its pressure
- change its direction
Turbine disks are normally made of a _______ alloy
nickel
Turbine blades are normally attached to the disk by the _______ method
fir-tree
Three types of turbine blades are:
- reaction
- impulse
- reaction-impulse
When the hot gases drive an impulse turbine, their direction is changed, and their speed is ________
(increase, decreases, or remains the same)
remains the same
When the hot gases drive a reaction turbine, their direction is changed, and their speed _______
(increases, decreases, or remains the same)
increases
Some turbine engines have used shrouded turbine blades to reduce _______ and minimise tip losses
vibration
Some modern high-performance turbofan engines reduce turbine blade tip losses by shrinking the turbine case when the engine is producing its maximum power. The case is shrunk by blowing a stream of _________ over it
fan-discharge air
The primary factor that limits the amount of power a gas turbine engine can produce is the maximum temperature that can be tolerated at the __________
turbine inlet
Air used to cool the turbine blades is taken from the __________ stages of the compressor
(higher or lower)
higher
The propeller reduction gearing used by a turboprop engine is normally of the multistage _______ type
planetary (epicyclical)
Turbine engines carry a _______ (larger or smaller) quantity of oil than reciprocating engines
smaller
Most of the heat absorbed by oil in a turbine engine lubricating system comes from the __________
turbine shaft bearings
Five functions of the oil in a turbine engine lubrication system are:
- reduce friction
- absorbs heat from the bearings
- protects against corrosion
- Picks up and carries contaminants into the filters
- warms fuel to prevent formation of ice crystals
Most turbine engine oil has a ________ base
(mineral or synthetic)
synthetic
Turbine engine oil has a _________ (lower or higher) viscosity than that used in a reciprocating engine
lower
Synthetic oils _________ (are or are not) interchangeable with straight mineral oils
are not
A turbine engine lubrication system that carries all of the oil in the engine itself is a ________ sump system
(wet or dry)
wet
The most popular type of lubrication system used on modern gas turbine engines is the _________ sump system
dry
In a hot-tank, dry-sump lubrication system, the oil cooler is located in the ________ subsystem
(pressure or scavenge)
pressure
If the oil filter should clog, the -_________ valve will unseat and allow unfiltered oil to flow through the system
filter bypass
After lubricating the bearings, oil is returned to the tank by the ______ pumps
scavenger
In a cold-tank, dry-sump lubrication system, the oil cooler is located in the _______ subsystem
(pressure or scavenger)
scavenger
The three basic subsystems of a turbine engine lubrication system are:
- pressure
- scavenger
- vent (slight positive pressure to pump to prevent cavitation)
Two types of bearings that are used to support the turbine/compressor shaft in a turbine engine are:
- Roller
- ball
Two types of air and oil seals used in a turbine engine are:
- layrinth seals
- carbon seals
The type of seal that allows the minimum amount of leakage is the ________ (carbon or labyrinth) seal
carbon
Oil returned to the oil tank by the scavenger pump contains a large amount of air. This air is removed by a/an
________
DeAerator
A labyrinth seal _________ seal by rubbing against its race
(does or does not)
does not
(carbon one does)
The air returned to the oil tank with the scavenged oil is used to ________ the oil tank
pressurise
Turbine engine oil tanks are pressurised to prevent the pressure pump from _______
cavitating
The two most generally used types of oil pressure pumps are:
- Spur gear type
- Gerotor type
A scavenger pump has a _________ capacity than a pressure pump
(larger or smaller)
larger
Approx. 150% larger due to the air which exists in the line coming back to reservoir
Vane-pumps are sometimes used as ________ pumps
(scavenger or pressure)
scavenger
Spur-gear, gerotor, and vane-type pumps are all ________-displacement pumps
(positive or variable)
positive
The weakened section of the drive shaft of an oil pump designed to break if the pump should seize is called a/an _____ section
shear
The effecitiveness of oil filters is measured in terms of ______
microns
One micron is one millionth of a/an _______.
This is approximately 0.000 039 Inch
meter
If a technician finds an oil filter with the red indicator button popped out, it means that the filter is partially ______
clogged
Two types of oil coolers used on a turbine engine are:
- Oil-to-Air
- Oil-to-Fuel
The oil-tank pressurizing system uses air returned to the tank with the oil by the ______ pump to maintain a positive air pressure above the oil in the tank
(pressure or scavenger)
scavenger
An early warning of metal particle contamination in the lubricating oil is provided to the flight crew by an indicator light actuated by a/an _________
chip detector
Three types of oil quantity indicators used on turbine engines are:
- dipstick
- sight gage
- Electrical oil quantity indicator
Two areas of an oil analysis program for turbine engines are:
- (SOAP) -Spectrometric Oil Analysis Program
- Evaluation of the filter element contents
About 75% of the air that passes through a gas turbine engine is used for _______
cooling
The hottest point in a gas turbine engine is found at the _______________
Turbine inlet guide vanes
The turbine blades in some high-performance turbine engines are hollow and are cooled by a flow of _______
compressor bleed air
what does it mean to ‘vaporise’ in terms of fuel nozzles?
The changing of a liquid into a vapor
What does ‘atomize’ mean in terms of fuel nozzles?
The process of breaking a liquid down into tiny droplets or a fine spray
What orifice(s) is the image from?
What is the following orifice(s) from?
What is a flow divider?
A component in a turbine engine fuel system that routes all of the fuel to the primary nozzles or primary orifices when starting the engine or when the RPM is low
Explain hydromechanical
Any device that combines fluid pressures with mechanical actions to achieve a desired result
What is meant by EPR?
EPR = Engine Pressure Ratio
The ratio of the turbine discharge total pressure to the compressor inlet total pressure
Turbine engine fuel pumps often have two stages: the low-pressure stage uses a ________ element, and the high-pressure stage uses a __________ element.
(centrifugal or spur-gear type)
centrifugal
spur-gear type
If the fuel filter should clog, fuel will flow to the engine through the ________ valve
filter bypass
If the gears should jam in an engine-driven fuel pump, extensive damage is prevented by a/an _______ in the drive shaft
shear section
The pressure produced by an engine-driven fuel pump is maintained by a/an _________
pressure relief valve
A jet engine fuel control, in its normal mode of operation, _________ give the pilot direct control of the amount of fuel metered into the engine
(does or does not)
does not
The fuel flowmeter used with a turbine engine measures the _______ (mass or volume) of the fuel and displays the information on the instrument panel in units of _______ (pounds or gallons) per hour
mass
pounds
Two basic types of fuel nozzles used in turbine engines are:
- atomising
- vaporising
Two types of atomizing fuel nozzles are:
- Simplex
- Duplex
In a duplex fuel nozzle, the fuel used to start the engine and for idling is the _______ fuel
(primary or secondary)
Primary
The spray pattern of the primary fuel is _______ than the pattern of both the primary and secondary fuel flowing together
wider
The component in a single-line duplex nozzle that opens the passage to the secondary discharge orifices when the fuel pressure is sufficiently high is the ________ valve
flow divider
When an engine equipped with a pressurizing and dump valve is shut down, the fuel in the nozzle manifolds _______
drains
The most critical temperature in a gas turbine engine is the _______ temperature
turbine inlet temperature
(TIT)
Four of the most basic parameters sensed by a turbine engine fuel control are:
- Power lever angle
- compressor inlet total temperature
- compressor RPM
- burner pressure
When the engine RPM is held constant by the fuel control, an increase in ambient or compressor inlet air temperature will cause the thrust to _________
(increase or decrease)
decrease
When the engine RPM is held constant by the fuel control, a decrease in ambient or compressor inlet air temperature will cause the TIT to ________
(increase or decrease)
increase
TIT = Turbine Inlet Temperature
Modern turbine engine fuel controls maintain the ______ (TIT or RPM) constant and allow the ________ (TIT or RPM) to vary with changing atmospheric conditions
TIT
RPM
TIT = Turbine Inlet Temperature
If the fuel flow to the engine is increased too rapidly during acceleration, the fire will likely go out because the mixture will be too ______ (rich or lean)
rich
The tendancy of a turbine engine to surge _______ (increases or decreases) with an increase in altitude
increases
The two basic classifications of turbine engine fuel controls are:
- Hydromechanical
- Electronic
A full-authority digital electronic control (FADEC) _______ (does or does not) control a hydromechanical fuel control
does not
The thrust setting parameter for a FADEC is the _______ (EPR or RPM)
EPR
When a turbine engine is controlled by a FADEC, the EPR is maintained constant for any position of the _______ as the flight environment conditions chnage
throttle lever
THe amount of water absorbed in jet fuel is determined by the temperature of the fuel.
Warm fuel will absorb and hold ________ water than cold fuel
(more)
more
Microscopic organisms that live in water that collects in a jet aircraft fuel tank form a scum that holds the water in contact with the metal of which the tank is made and causes ______
corrosion
Turbine engines normally have _______ (how many) igniter plugs
2
The fuel-air mixture in combustors that have no igniter is ignited by flames carried from other combustors through ________
flame tubes
The conditions for igniting the fuel-air mixture in a turbine engine is ________ severe than they are in a reciprocating engine
(more or less)
more
Turbine engine ignition systems are rated according to the energy in the spark in units of ________
(joules or watts)
joules
The duration of the spark across the gaps of a turbine engine igniter is _______
(short or long)
short
A high-energy ignition system produces the high current in each spark by storing electrons in a/an _________
capacitor
In a dual-spool turbine engine, the starter rotates the _______ pressure compressor
(high or low)
high
The engines on most jet transport aircraft are started with _______ starters
(air or electric)
air
Air for starting the engines on a jet transport aircraft is normally supplied by the ______
APU
The primary advantage of an air turbine starter is its low weight to ________ ratio
power/torque
An air turbine starter requires a ______ (large or small) volume of _______ (high or low)-pressure compressor air
large
low
Three sources of compressed air to operate an air turbine starter are:
- APU
- GPU
- Cross-flow from an operating engine
The air turbine starter described in this text is disconnected from the engine when the engine starts by a/an _________
sprag clutch
If the air valve does not shut off after the engine has started, the turbine will be protected from reaching its burst speed by the turbine nozzle operating in a/an _______condition
choked
The type of starter used by most small business jet turbine engines is a/an _______
starter-generator
The APU in most modern jet transports are located in the _____________
(airplane tail cone or in the landing gear wheel well)
airplane tail cone
The two things supplied by an APU are:
- electrical power
- compressed air
The type of fuel control used on most APUs is a/an __________
(Hydromechanical control or FADEC)
FADEC
The most common type of exhaust duct for smaller turboket and turbofan engines is a ________ duct
(convergent or divergent)
convergent
The exhaust cone is considered to be an _________ component
(engine or airframe)
engine
Exhaust gases leave the exhaust nozzle in most turbojet and low-bypass turbofan engines at the speed of _______
sound
A convergent-divergent exhaust nozzle increases the thrust produced at supersonic flights by increasing the ________ (pressure or velocity) of the exhaust gases
velocity
The amount of noise a turbojet engine produces is related to the _________ of the exhaust gases
velocity
Low frequency sound waves travel a ________ distance through the air than high-frequency waves
(greater or shorter)
greater
The two types of thrust reversers are those that use ______ doors and _____ vanes
clamshell
cascade
When the afterburner is being used, the area of the exhaust nozzle is ________
(increased or decreased)
increased
Most powerplant fire protection systems _______ automatically discharge the extinguishing agent when the fire is detected
(do or do not)
do not
A fire that involves combustible liquid as its fuel is a Class ______ fire
B
Two classes of detectors used in a powerplant fire protection system are:
- Fire detector
- Overheat detector
A thermoswitch detector system ________ an overheat detector
(is or is not)
is not
Thermoswitches are connected in ________
(series or parallel)
parallel
If the wire between two single-loop thermoswitch detectors is broken, the system _______ detect a fire
(will or will not)
will
A high-rate of temperature rise triggers a fire warning by a __________ detection system
(thermoswitch or thermocouple)
thermocouple
The thermocouple sensors in a thermocouple fire detection system are connected in _________
(series or parallel)
series
In a thermocouple fire detection system, current in the thermocouple circuit flows through the coil of the _________ relay
(sensitive or slave)
sensitive
The current that flows in a thermocouple circuit is proportional to the ___________ between the various junctions
temperature difference
Two types of continuous loop fire and overheat detectors are:
- thermistor
- pneumatic
The resistance of a thermistor material ________ as its temperature increases
(increases or decreases)
decreases
Pneumatic continuous-loop fire detection systems contain an element that _________ gas when it gets hot
(absorbs or releases)
releases
The sensor element of a Systron-Donner pneumatic fire detection system is filled with helium gas.
The pressure of the helium varies with its temperature, and it is used to close the pressure switch if a/an _________ occurs
(fire or overheat condition)
overheat condition
The center wire in a Systron-Donner pneumatic fire detector absorbs hydrogen and releases it to close the pressure switch if a/an _________ occurs
(fire or overheat condition)
fire
If a break should occur in a Systron-Donner pneumatic fire detector, the ________ gas will escape, which opens the integrity switch
(helium of hydrogen)
helium
The warning light in the Systron-Donner fire detection system will not illuminate if the integrity switch is ______ (open or closed)
open
Four fire-extinguishing agents that can be used for powerplant fires are:
- Carbon Dioxide
- Liquid nitrogen
- Halon 1211
- Halon 1301
One limitation of liquid nitrogen is that because it is a cryogenic liquid, it must be stored in a ______ bottle
Dewar
If an installed CO2 fire-extinguishing system is discharged in the normal manner, the ________ disk on the outside of the fuselage is blown out
(yellow or red)
yellow
The agent in an HRD container is discharged when the sealing disk is ruptured by a cutter driven by a _______
ignited powder charge
The Freon, or Halon, fire-extinguishing agent in an HRD bottle is propelled from the bottle by a charge of compressed _______
nitrogen
If an HRD fire extinguishing bottle is discharged because of an overheat condition, the _______ (yellow or red) disk on the outside of the fuselage is blown out
red
Halon 1301 ______ corrosive to aluminium
(is or is not)
is not
Six things that happen when the fire-pull handle in the cockpit is pulled are:
- Engine fuel shutoff valve closes
- Generator field relay trips
- Engine bleed air valve closes
- Anti-ice valve closes
- Hydraulic supply shutoff valve closes
- Hydraulic pump low-pressure warning light turns off
The fire extinguishing agent ________ discharged when the fire-pull handle is pulled
(is or is not)
is not
The tubing that carries fire-extinguishing agents is color coded with a stripe of _______ (colour) tape and a series of ______ (what symbols)
brown
diamonds
When installing a grommet around a continuous-loop element, the slit in the grommet should face the _________ of the nearest bend
(inside or outside)
outside
