Multiengined

Multiengined is an adjective describing machines or vehicles equipped with more than one engine or propulsion unit. The term is commonly used in aviation but can apply to ships, trains, and, less commonly, road vehicles. In aviation, multiengined aircraft have two or more propulsion systems, offering redundancy in case of an engine failure and enabling greater overall power or range. The design and operation considerations differ by number of engines: two-engine (twin) aircraft must meet engine-out performance requirements, while four-engine aircraft emphasize reliability and thrust distribution. Certification regimes, such as ETOPS for twin-engined long-range airliners, influence routes and maintenance.

In maritime contexts, ships may use multiple engines to provide redundancy, maneuverability, and controllable power. Some vessels have independent propulsion systems for each engine, while others use a single shaft with multiple engines coupled to it.

In rail and road transport, multiengined configurations appear in diesel-electric locomotives with several prime movers, or in high-performance or experimental road vehicles featuring multiple power sources. Hybrid or plug-in electric layouts may incorporate several engines or motors to improve efficiency or power delivery.

Operational implications include increased weight, fuel consumption, maintenance complexity, and cost, balanced by improved reliability, thrust, or performance. The prevalence and configuration of multiengined systems vary by industry, technology, and regulatory requirements.