Editing Engine configuration (section)

==== Other layouts ====
[[Radial engine]]s have cylinders mounted radially around a central crankcase. [[Rotary engine]]s have a similar configuration, except that the crankshaft is fixed and the cylinders rotate around it. (This is different from the [[Wankel engine]] configuration described below.) Radial and rotary engine designs were widely used in early [[aircraft engine]]s.

[[U engine]]s consist of two separate straight engines (complete with separate crankshafts) joined by gears or chains. Most U engines have four cylinders (i.e. two straight-two engines combined), such as [[U engine#Square four engine|square four engines]] and [[U engine#Tandem twin engine|tandem twin engines]]. Similar to U engines, [[H engine]]s consist of two separate flat engines joined by gears or chains. H engines have been produced with between 4 and 24 cylinders.

An [[opposed-piston engine]] is similar to a flat engine in that pairs of pistons are co-axial but rather than sharing a crankshaft, instead share a single combustion chamber per pair of pistons. The crankshaft configuration varies amongst opposed-engine designs. One layout has a flat/boxer engine at its center and adds an additional opposed-piston to each end so there are two pistons per cylinder on each side.

An [[X engine]] is essentially two V engines joined by a common crankshaft. A majority of these were existing V-12 engines converted into an X-24 configuration.

The [[Cam_engine#Wobble_plate_engine|Swashplate engine]] with the K-Cycle engine is where pairs of pistons are in an opposed configuration sharing a cylinder and combustion chamber.

A Delta engine has three (or its multiple) cylinders having opposing pistons, aligned in three separate planes or 'banks', so that they appear to be in a Δ when viewed along the axis of the main-shaft. An example of this type of layout is the [[Napier Deltic]].