US Patent 11939077 Fan clutch for convertible engine

Systems and methods include providing an aircraft with a fuselage and a convertible engine disposed within the fuselage. The convertible engine is operable as a turbofan engine in a thrust mode and a turboshaft engine in a shaft power mode. The convertible engine includes a housing, an engine core having a low pressure turbine shaft, and a bypass fan system. The bypass fan system includes a bypass fan having a fan clutch. The fan clutch selectively couples at least a portion of the bypass fan to the low pressure turbine shaft when the convertible engine is operated in the thrust mode and decouples at least a portion of the bypass fan from the low pressure turbine shaft when the convertible engine is operated in the shaft power mode.