Abstract: This invention provides a multi-fan system separated core engine type turbofan engine in which high pressure air is used as the working fluid for a turbine which drives a fan, thereby reducing the manufacturing costs of the turbofan engine and simplifying the constitution thereof. A turbine for driving a fan 11 which is provided in a propulsion device 3 of the multi-fan system separated core engine type turbofan engine 1 is an air turbine 13 which is driven by the supply through a duct 9 of a part of high pressure air compressed in a compressor 5 of a core engine 2. Since the working fluid of the air turbine 13 for driving the fan 11 is not high temperature combustion gas, there is no need to use expensive heat-resistant material for the turbine, and thus the propulsion device 3 can be manufactured at low cost, the constitution thereof can be simplified, and operational control can be ameliorated.

Abstract: A low-noise separated core engine type turbofan engine is provided in which noise generated by a control propulsion device is reduced by using high pressure air as the working fluid of a turbine for driving a control fan used in the attitude control of the airframe. A control fan 17 of a separated core engine type turbofan engine 1, which is comprised in a control propulsion device 4 provided for attitude control of the aircraft, is driven by an air turbine 19 which uses as working fluid high pressure air compressed by a compressor 6 of the core engine 2 and supplied through a duct 10. The speed of the working fluid which is discharged from the control fan 17 and air turbine 19 is sufficiently low for attitude control and not as high as the speed of the working fluid which is discharged from a propulsion device 3 which is provided for thrust, and thus noise generated by the control propulsion device 4 can be reduced.

Abstract: This invention provides a multi-fan system separated core engine type turbofan engine in which high pressure air is used as the working fluid for a turbine which drives a fan, thereby reducing the manufacturing costs of the turbofan engine and simplifying the constitution thereof. A turbine for driving a fan 11 which is provided in a propulsion device 3 of the multi-fan system separated core engine type turbofan engine 1 is an air turbine 13 which is driven by the supply through a duct 9 of a part of high pressure air compressed in a compressor 5 of a core engine 2. Since the working fluid of the air turbine 13 for driving the fan 11 is not high temperature combustion gas, there is no need to use expensive heat-resistant material for the turbine, and thus the propulsion device 3 can be manufactured at low cost, the constitution thereof can be simplified, and operational control can be ameliorated.

Abstract: A low-noise separated core engine type turbofan engine is provided in which noise generated by a control propulsion device is reduced by using high pressure air as the working fluid of a turbine for driving a control fan used in the attitude control of the airframe. A control fan 17 of a separated core engine type turbofan engine 1, which is comprised in a control propulsion device 4 provided for attitude control of the aircraft, is driven by an air turbine 19 which uses as working fluid high pressure air compressed by a compressor 6 of the core engine 2 and supplied through a duct 10. The speed of the working fluid which is discharged from the control fan 17 and air turbine 19 is sufficiently low for attitude control and not as high as the speed of the working fluid which is discharged from a propulsion device 3 which is provided for thrust, and thus noise generated by the control propulsion device 4 can be reduced.