Aircraft Systems Flashcards
Classification of 2 engine types
Cylinder arrangement, radial, inline, vtype, opposed
Operating cycle, 2 or 4
Cooling, air or liquid
Fixed pitch prop
Climb vs cruise prop, low vs high pitch
Some engines have shaft geared
Tachometer in rpm engine and prop
Adjustable pitch prop
Constant speed prop most common, maintains constant rpm despite air load
Most efficient
2 controlls: throttle for power output and prop for engine rpm
Constant speed prop governor maintains set rpm
Increase in airspeed or decrease in prop load causes prop angle to increase to maintain rpm
Decrease in airspeed or increase in prop load causes prop angle to decrease
Manifold pressure gauge
Absolute pressure of fuel-air mixture inside intake manifold
Color coded indicating engine ops range
Change manifold pressure and rpm in this order to avoid engine overstress
Reduce manifold pressure before rpm
Increase rpm before increasing manifold
Radial engines: minimize ops time at max rpm and manifold pressures
2 induction systems
- Carburetor mixes fuel and air before intake manifold
- Fuel injection mixes fuel and air immediately before each cylinder or injects fuel into cylinder
Types of carburetors
Flow type
Pressure type
Float type carburetor
Outside air through filter through venturi = narrow throat in carb
Low pressure area created forcing fuel to flow through main fuel jet at throat. Fuel then flows into airstream, mixed with air, drawn into intake manifold and combustion chamber
Float type disadvantages
Bad with abrupt maneuvers
Discharge of fuel at low pressure leads to incomplete vaporization
Icing tendency
Mixture Control
Full rich at sea level
Lower air density at altitude requires reduction in fuel density
Otherwise carbon build up occurs due to incomplete combustion causing loss of power
Increase mixture when descending
Monitor engine temp or exhaust gas temp
Carboator icing
Due to fuel vaporization and decrease in air pressure in venturi
Below 70F and above 80% humidity
Notice vibration, engine roughness
Use carboator heat to counter, will reduce engine power, use for a few min to melt ice
Temperature gauges
For outside air and carburetor air temp
Fuel injection system components
Engine driving fuel pump for after engine start
Fuel air control unit
Fuel manifold
Discharge nozzles
Auxiliary fuel pump for engine start
Fuel pressure/flow indicators
Fuel injection advantages
Reducing evaporation icing
Better fuel flow
Faster throttle response
Precise control of mixture
Better fuel distribution
Easier cold weather starts
Disadvantages
Difficulty starting hot engine, during hot days or restarting
Superchargers and Turbosuperchargers
Increase air pressure running through engine and therefor increase service ceiling of aircraft
Supercharger
Uses engine driven air compressor
1, 2 or variable speed
One or more stages
Intake air passes through ducts to carburetor, fuel-air charge ducted to supercharger blower impeller, accelerates outward, passes through diffuser, velocity traded for pressure, directed to cylinder
Turbocharger elements
Compressor and turbine
Induction air accelerated by impeller, large volume into compressor producing high pressure, high density air
Engine exhaust gas used to drive turbine wheel and impeller - adjusted with amount of exhaust gas directed to turbine vs waste gate
Use intercooler to cool compressed air
Overboost
Produce manifold pressure that exceeds engine limitations
Manual vs oil pressure control of waste gate
Advance throttle carefully
Oil temp in normal range first
Allow turbocharger to cool and turbine to slow before shutting off engine
Ignition system
2x magnetos, spark plugs, hich tension leads, ignition switch
Engine oil system functions
Lubrication of engine moving parts
Cooling of engine by reducing friction
Removing heat from cylinders
Seal between cylinder walls and pistons
Carrying away contaminants
Wet sump vs dry sump
Wet sump part of engine, pump drawing from sump routing into engine, then returns to sump
Dry sump external to the engine in a separate oil tank allowing for greater volumes of oil
Engine air cooling system
Air inlet, baffles, fins in cylinders, cowl flaps
Exhaust system
Exhaust valve and piping attached to cylinders
Muffler and Muffler shroud
EGT probe to measure exhaust manifold temp
Starting system
Direct cranking in small aircraft
Battery or external power, wiring, switches, solenoids
Combustion: causes of detonation
Too low fuel grade than specified
Low rpm and very high manifold pressures
High power settings plus excessively lean mix
Extended ground ops or steep climbs with reduced cylinder cooling
Preignition
Residual hot spot in cylinder
Carbon deposit on spark plug or cracked spark plug insulator or other damage
Severe engine damage, lose power
FADEC
Full Authority Digital Engine Control
Eliminates need for magnetos, carburetor heat, mix control, engine priming
Turbine engine consists of
Air inlet, compressor, combustion chambers, turbine section, exhaust
types of compressors
Centrifugal flow
Axial flow
Centrifugal-axial flow
Types of turbine engine
Turbo jet
Turboprop
Turbo fan
Turboshaft
Turbojet
Compressor passes inlet air to combustion chamber with fuel and igniter, expanding air drives turbine, connected to shaft, connected to compressor
Turboprop
Exhaust gas drives turbine with shaft connected to reduction gear assembly for prop
Turbofan
Secondary airflow bypass combustion chamber, increases thrust, cools engine, aids with noise suppression
Turbine engine instruments
Oil pressure, oil temp, engine speed, exhaust gas temp, fuel flow
Engine pressure ratio, turbine discharge pressure, torque
Engine pressure ratio EPR
For power output
Ratio of turbine discharge to compressor inlet pressure
Exhaust gas temp EGT
Prevent overheating of turbine with temp sensors
Turbine inlet temp, turbine outlet temp, interstage turbine temp, turbine gas temp
N1 N2 Indicators
N1 rotational speed of low pressure compressor
N2 rotational speed of high pressure compressor
Turbine engine operations
Temp limits
Thrust variations
Forgein object damage
Hot/Hung start
Compressor stalls
Flameout
Performance comparisons 3 options
Brake horsepower - usable hp delivered to output shaft
Net thrust - produced by turbojet or turbofan
Thrust hp - hp equivalent of the thrust produced by turbojet and turbofan
Equivalent shaft hp - sum of shaft hp to prop and thrust hp by exhaust => in turboprop
Airframe systems
Fuel, electrical, hydraulic, oxygen systems
Fuel systems
Gravity fed in high wing planes
2 fuel pumps in low wing planes, one engine driven, one electrical for starting and backup
Fuel primer helps evaporate fuel during cold start
Fuel strainers, sumps, drains
Removes water and sediments, settle in sump, remove through drain before every flight
Fuel contamination
Inadequate pre flight
Service with improperly filtered fuel from small tanks, drums
Store with partially filled tanks
Lack of maintenance
Fuel system icing
Undisolved or dissolved
Entrained = minute water particles suspended in fuel
Free water through bad refueling or settling
Prevent icing
Additives
Hexylene glycol, methanol derivatives, ethylene glycol monoethyl ether
Refueling
Avoid static electricity
Ground wire to aircraft
Ground refueling drum
Connect nozzle to aircraft
Heating systems
Fuel fired heaters
Exhaust heating systems
Combustion heater systems
Bleed air heating systems
Electrical system
Alternator/generator
Battery
Master/battery switch
Alternator/generator switch
Bus bar, fuses, circuit breakers
Voltage regulator
Ammeter/load meter
Electrical wiring
Equipment that needs power
Position lights
Anticollision lights
Landing lights
Taxi lights
Cabin lights
Instrument lights
Radio equipment
Turn indicator
Fuel.gauges
Electric fuel pump
Stall warning
Pitot heat
Starting motor
Hydraulic systems used for..
Wheel brakes
Retractable landing gear
Constant speed prop
Flight control surfaces
Wing flaps
Spoilers
Hydraulic systems consist of
Reservoir
Pump
Filter
Selector valve
Relief valve
Actuator
Tricycle landing gear
Can brake harder
Better visibility
Prevent swerving
Nose gear either steerable or castering
Pressurized aircraft
Aircraft Altitude
Ambient temp
Ambient pressure
Cabin altitude
Differential pressure
Decompression
Explosive vs rapid
Hypoxia and unconsciousness
Oxygen systems
Flight crew between 12500-14000ft
Everyone above 15000ft
Some have issues at 15000ft
Oxygen system types
Oxygen mask
Cannula
Diluter demand
Pressure demand
Continuous flow
Electrical pulse demand
Anti ice and deice wing systems
Boot system
Thermal anti ice
Weeping wing
Windscreen and prop anti ice
Using alcohol or wires producing electrical heat
Or prop boots
CLHAND
150s and 96X has Continental
Carburetor
Lycoming
Horizontally opposed
Air cooled
Naturally aspirated
Direct drive
