twinradialengine

A twin radial engine is an aircraft propulsion arrangement that combines two radial piston engines to power a single airframe, or to provide redundancy in a compact installation. The two engines are typically mounted on a common frame and may drive a single propeller through a gearbox or, less commonly, drive separate propellers.

There are two main configurations: tied-crankcase units built to share a single crankcase or case assembled from two independent engine modules, and paired engines mechanically linked by a geared connection to drive a single propeller. In some layouts, one or both engines may have their own cooling systems; in others, airflow is shared or optimized by nacelle design. Mechanical coupling requires careful balancing, synchronization of firing order where possible, and a robust propeller reduction gear to handle combined torque.

Advantages include higher total power in a compact footprint and potential redundancy, useful for research aircraft or missions requiring extra thrust. Disadvantages are increased weight, complexity, maintenance, and cooling or vibration management challenges; engine-out performance and reliability may not be straightforward.

Historically, twin radial configurations were explored in the interwar and early postwar periods as an approach to exceed single-engine power limits before large, high-power radials became available. They remained relatively rare and mostly confined to experimental or prototype airframes.

See also: Radial engine; Twin-engine aircraft; Coupled engine; Aircraft propulsion.