Inline engine (aeronautics)

In aviation, an inline engine is a reciprocating engine with banks of cylinders, one behind another, rather than rows of cylinders, with each bank having any number of cylinders, although more than six is uncommon. The major reciprocating-engine alternative configuration is the radial engine, where the cylinders are placed in a circular or "star" arrangement.

The term "inline" is used somewhat differently for aircraft engines than automotive engines. For automotive engines, the term ‘inline’ refers only to straight engines (those with a single bank of cylinders). But for aircraft, ‘inline’ can also refer to engines which are not of the straight configuration, such as V, H, or horizontally opposed.^{[citation needed]}