Electrically coupled supercharger for a turboshaft engine

A turboshaft engine (10) for use in an aircraft, includes a spool (14) having a turbine (18) and a gas generator compressor (20) mounted thereto, a source of heat (22) positioned between the turbine (18) and the compressor (20), a first shaft (12) and a free turbine (24) mounted to the first shaft (12), a free compressor (40) driven by a second shaft (42), and a control system (30) for transferring power between the spool (14) and the first shaft (12). The operating speed of the gas generator compressor (20) is re-matched in order to improve the efficiency and surge margin of the gas generator compressor (20) and to improve the transient performance of the turboshaft engine (10).