WMU AVS 1225-140: Part 1 Engine Lecture

Reciprocating engines

A type of heat engine that changes the reciprocating (back and forth) motion of the piston inside the cylinders to rotary motion of a crank-shaft

Four-stroke cycle example

Motorcycle engines

Two-stroke cycle example

Ultralight aircraft + water vehicles

Powerplant

The complete installation of an aircraft engine, propeller, and all accessories needed for its proper function

Heat Engine

A mechanical device that converts the chemical energy in a fuel into heat energy which is then used for work

External combustion engine (EC)

A form of heat engine in which the fuel releases its energy outside of the engine (ex: steam engine)

Internal combustion engine (IC)

A type of heat engine where the fuel and air mixture is burned inside the engine to heat and expand the air (ex: car engines)

Reaction Engines

A form of heat engine that produces thrust by heating a mass of air inside the engine and discharging it at a high velocity through a specially shaped nozzle (ex: Turbojets, Rockets, Ramjets, etc)

Four-strole cycle

Constant-volume cycle of energy transformation where there are separate strokes for intake, compression, power, and exhaust.

Two-stroke cycle

Constant-volume cycle of energy transformation that completes its operating cycle in two strikes of the piston, one up and one down.

Diesel cycle

The air inside the cylinder is raised to the fuel ignition temp/pressure, and then the fuel is injected (no need for a spark plug to ignite the fuel)

Reciprocating engines + Reaction engines w/prop are measured in?

Horsepower

What units are used to measure reaction engine thrust?

Pounds

What happens when an engine is coupled to a wheel or propeller?

The power developed enables mechanical work to be done (Work = Force x Distance)