Design and Construction of Reciprocating Engines

Design and Construction of Reciprocating Engines

Knowing the design and construction of the accident engine is crucial as an aircraft

accident investigator. Radial, in-line, "V" type and horizontally opposed are the different

types of reciprocating engines. They maybe classified according to cylinder arrangement,

liquid cooled and air cooled. The basic components of a reciprocating engine are the

crankcase, cylinders, pistons, connecting rods, valves, valve train, crankshaft, head and spark plugs.

Radial engine is known to be craggy, reliable and can have one or more rows

of cylinders arranged radically around a central crankcase. Three, five, seven or nine

cylinders can be found in a row and will have different power output from different sizes of

the engines. Typical in-line engine has even number of cylinders, a small frontal area

which helps in streamlining, higher weight-to-horsepower ratio and is either liquid cooled or

air cooled. When cylinders are operating below the crankshaft, it is called an inverted engine

V-type engine as compare to inline configuration, reduces the overall engine length,

height and weight. Most V-type engines are either liquid or air cooled and generally have 12

cylinders that are arranged 60 degree apart along the axis of the crankshaft. Opposed-type

engine has two cylinder heads on opposite sides of the crankshaft and is either liquid cooled

or air cooled. Due to its flat and narrow profile, it is capable for horizontal installation on

aircraft wings too. It has a low weight-to-horsepower ratio and able to offset vibration caused

by pistons movement.

Crankcase which supports and encloses the crankshaft for oil lubrication can be made

of cast, forged aluminum alloy and forged steel is the foundation of the engine. Failure of the

crankcase will lead to multiple problems like rough running engine, oil starvation and

misalignment of critical parts that halt the...