US Patent 11891899 Dual engine system

A dual-engine system of an aircraft that includes at least one main engine is provided. The dual-engine system includes a sustainer engine, a booster engine configured to augment a power output of the sustainer engine, and a gearbox coupled to the sustainer engine and the booster engine. An output of the gearbox is configured to selectively combine the power output of the sustainer engine with the booster engine.