Aviation Powerplant Systems & Components: How Aircraft Engines and Their Systems Work

Powerplant

The complete engine installation that produces thrust, including the engine and major supporting systems.

Reciprocating engine

An engine that converts pressure from burning fuel-air into linear piston motion.

Gas turbine engine

An engine that uses continuous airflow for compression, combustion, and expansion.

Engine cycle

The repeating sequence of events that converts chemical energy into mechanical work.

Lean mixture

Condition where an engine runs with too little fuel in relation to air, raising combustion temperatures.

Compressor efficiency

The performance level at which a compressor can pressurize air.

Four-stroke cycle

The engine cycle that includes intake, compression, power, and exhaust strokes.

Volumetric efficiency

The effectiveness of an engine to ingest air.

Turbine engine sections

Inlet, compressor, combustor, turbine, and exhaust/nozzle.

Airflow machine

A term describing turbines, focusing on airflow management for combustion.

Mixture control

The system that regulates the air-fuel mixture entering the engine.

Camshaft

The component that controls valve timing in an engine.

Crankcase

The main structural body of the engine that houses crankshaft bearings.

Crankshaft

The part that converts piston motion into rotation.

Piston rings

Components that seal the combustion chamber and control oil flow.

Valve train

The assembly that controls the timing of airflow in and out of the engine.

Reduction gearbox

A mechanical component that adjusts engine rotation to optimize propeller RPM.

Carburetor ice

Ice that forms in the carburetor due to pressure drops and fuel evaporation.

Supercharger

An air compressor that is mechanically driven by the engine.

Turbocharger

An air compressor driven by exhaust gas energy.

Fuel metering

The process of delivering the correct amount of fuel to the engine combustion chamber.

Venturi

A tube that narrows to create a pressure drop to draw fuel in carburetors.

Fuel injection

A system that delivers fuel directly into the combustion chamber for more precise control.

Ignition system

The system responsible for providing the spark for combustion.

Magnetos

Self-contained electrical generators used in piston engines for ignition.

Turbine ignition

An ignition system in turbine engines that uses exciters and igniter plugs.

Lubrication system

A system that reduces friction and carries away heat and contaminants from engine components.

Wet sump

A lubrication system where oil is stored in the engine crankcase.

Dry sump

A lubrication system where oil is stored in a separate external tank.

Cooling system

The method of managing heat within the engine to prevent overheating.

Air-cooled engine

An engine that relies on airflow to dissipate heat via cooling fins.

Liquid-cooled engine

An engine that uses coolant to regulate temperature, less common in aircraft.

Exhaust system

The component that routes exhaust gases away from the engine.

Wastegate

A valve that regulates exhaust flow to control turbocharger boost.

Fire detection system

A safety feature that senses overheat or fire conditions in engine compartments.

Fixed-pitch propeller

A propeller with blades set at a fixed angle, varying RPM with airspeed.

Constant-speed propeller

A propeller that adjusts blade angle to maintain selected RPM.

Governor

A device that controls the blade pitch of a constant-speed propeller based on RPM.

Horsepower

A measure of engine power output related to RPM and torque.

Turbine start problems

Issues like hot starts or hung starts during turbine engine startup.

Inspection and troubleshooting

The process of diagnosing and resolving engine problems using symptoms and indications.

Typical symptoms of low oil pressure

Can be caused by low oil quantity, overheated oil, or worn bearings.

Common failure patterns

Trends in engine issues often related to maintenance mistakes or process breakdowns.

Torque

A measure of rotational force that is linked to horsepower in engines.

Engine instruments

Devices that provide feedback on engine performance parameters.

Manifold pressure

A measure of pressure in the intake manifold, indicating engine airflow.

Cylinder head temperature (CHT)

A measure of the thermal stress experienced by the cylinder head during operation.

Exhaust gas temperature (EGT)

A measurement used to indicate the efficiency and health of the combustion process.