Aircraft Powerplant - Chapter 1 Vocabulary

Vocabulary flashcards covering key terms and concepts from the Aircraft Powerplant lecture notes.

Reciprocating engine

An engine that uses one or more pistons to convert pressure from combustion into rotating motion via a crankshaft.

Turboprop

A jet engine that drives a propeller through a turbine–propeller connection.

Jet engine

A turbine engine that produces thrust by expelling high‑speed exhaust; includes turbojet and turbofan types, plus APU in some applications.

Turbojet

A jet engine in which all thrust is produced by the jet of exhaust; air is compressed, combusted, and expelled.

Turbofan

A jet engine with a large fan at the front that provides additional thrust and efficiency, especially at subsonic speeds.

APU

Auxiliary Power Unit; a small turbine used to start the main engines or provide electrical/hydraulic power while on the ground.

Rocket engine

An engine that produces thrust by expelling stored propellants without atmospheric oxygen.

Piston

A moving cylindrical component that compresses/receives the air–fuel mixture and transfers force to the crankshaft.

Cylinder

The chamber in which a piston moves and combustion occurs.

Crankshaft

The shaft that converts the piston’s linear motion into rotating motion to drive the propeller or accessories.

Connecting rod

The rod connecting the piston to the crankshaft, transmitting force during a cycle.

Camshaft

A shaft with cam lobes that operate the opening/closing of valves at set timing.

Spark plug

A device that provides the electric spark to ignite the air–fuel mixture inside the cylinder.

Intake

The port or manifold through which the air–fuel mixture enters the cylinder.

Exhaust

The path through which burnt gases exit the cylinder after combustion.

Water jacket

Coolant-filled passages around the cylinders used to remove heat from the engine.

Valves

Intake and exhaust valves that control the flow of air, fuel, and spent gases in the cylinder.

Fuel-air mixture

The combination of air and fuel prepared for combustion in the cylinder.

Ignition

The process of initiating combustion in the air–fuel mixture, typically by a spark plug.

Four-stroke engine

A cycle consisting of intake, compression, power, and exhaust strokes.

Internal-combustion engine

An engine that converts chemical energy from fuel into mechanical work via combustion inside the engine; some variants (like jet engines) may not use pistons.

Deadweight

Non-payload weight that reduces aircraft payload capacity.

Drag

Air resistance that slows the aircraft; a key design consideration for powerplants.

Payload

The useful load carried by the aircraft, excluding fuel and crew.

Cruise power (%)

The typical percentage of full power used during cruise, often around 65%–75% in general aviation.

Maximum takeoff power

The brief high-power setting used during takeoff, usually for a few minutes.

Lightweight design

Aims to minimize deadweight to maximize payload and performance.

Reliability

Dependable operation and safety of the powerplant during flight.

Redundancy

Duplication of critical components to improve reliability and safety.

Duplicate parts

Using extra or spare parts to ensure continued operation in case of failure.

Rotary-type radial engine

A radial engine where the crankshaft is stationary and the cylinders rotate with the crankcase; propeller attached to the engine case.

Radial engine (single-row)

Cylinders arranged around the crankshaft in a single circular row; common in WWI era.

Radial engine (double-row)

Radial with two concentric rows of cylinders, increasing displacement and power.

Inline engine

Cylinders arranged in a single row along the crankshaft; often upright or inverted.

Inverted inline

Inline engine mounted upside-down to improve pilot visibility and ground clearance.

V-type engine

Engines with two cylinder banks arranged in a V around the crankshaft; commonly 60°, 45°, or 90° apart.

Opposed/flat/boxer engine

Cylinders lie horizontally in two banks on opposite sides of the crankshaft; commonly called a boxer engine.

Boxer engine

Another term for an opposed/two‑bank flat engine with horizontally opposed cylinders.

Multi-row radial

Radial engines with more than one cylinder row, offering high power in a compact form.

R-4360 Wasp Major

28-cylinder four‑row radial engine by Pratt & Whitney, up to about 3,500 hp.

Pratt & Whitney

A major American aircraft engine manufacturer responsible for many piston and turbine engines.

Wasp Major horsepower

Maximum output around 3,500 horsepower for the R-4360 in certain configurations.

Water-cooled engine

Engine cooled by circulating liquid coolant through passages around the cylinders.

Air-cooled engine

Engine cooled by air flowing over the cylinder fins; common in many GA piston engines.

Displacement

The swept volume of all cylinders, typically measured in cubic inches or liters.

Displacement designation (e.g., IO-360)

Codes in engine names indicating configuration and displacement; IO indicates fuel injection and horizontally opposed cylinders, 360 is the displacement in cubic inches.

IO-360-L2A

A Lycoming fuel-injected, horizontally opposed engine with 360 cubic inches displacement (used on some Cessna 172 variants).

O-235-N2C

An opposed-cylinder engine designation; 235 cubic inches displacement with certain features (e.g., fuel delivery type).

Lycoming

A major manufacturer of piston aircraft engines, known for IO and O series engines.

Cylinder arrangement classification

Classification by how cylinders are arranged relative to the crankshaft (inline, V, radial, opposed, etc.).

Cooling method classification

Classification by how engines are cooled (air-cooled vs water-cooled).

Post-World War I engines

Engines developed after WWI, including radial, multiple-row radial, and opposed/flat (O-type) designs.

World War I rotary engine (rotary radial)

A radial engine where the crankshaft remains stationary and the cylinders rotate; propeller attached to the engine case.

World War I inline engine

Cylinders arranged in a single row; typically upright or inverted for cooling and visibility.

World War I V-type engine

Cylinders arranged in two banks forming a V around the crankshaft.

World War I radial advantages

Air cooling is effective; fewer moving parts near the propeller; compact frontal area.

World War I radial disadvantages

Large gyroscopic and torque effects; lubrication challenges with castor oil; higher drag.

World War I inline advantages

Smaller frontal area and streamlined nacelle; better visibility when inverted.

World War I inline disadvantages

Lower power-to-weight and more complex cooling for rear cylinders.

World War I V-type advantages

Higher horsepower-to-weight than inline with manageable frontal area.

Opposed/Flat/Boxer advantages

Efficient, compact, low drag; good for streamlined nacelles and balanced weight.

Opposed/Flat/Boxer disadvantages

Coolant and lubrication considerations; complex for large displacements.

Cylinder arrangement importance

Crucial factor in engine design affecting drag, cooling, vibration, and maintenance.