Turbofan engine

A turbofan engine, comprising:

• a core engine including at least one high pressure spool assembly and a combustion chamber;
• a modified fan retrofittably mechanically coupled to a low pressure turbine that is in turn driven by hot gases generated by the core engine;
• wherein said modified fan is derived from or replaces an unmodified fan;
• wherein said modified fan is configured for generating a reduced bypass flow during operation of the turbofan engine relative to the unmodified fan, effective for said low pressure turbine to generate an excess shaft power above a baseline power required for driving said modified fan during operation of the turbofan engine;
• wherein the modified fan comprises a plurality of modified fan blades, wherein each said modified fan blade of said plurality of modified fan blades of the modified fan includes a corresponding inner blade portion having an inner radial portion geometry and an angle of attack;
• wherein said inner blade portion of each fan blade of the modified fan radially extends from a respective blade root to a radial position corresponding to the radial position of a leading edge of a casing of the core engine;
• and
• wherein at least an outer radial portion of the fan blades is absent from the modified fan.

A turbofan engine, comprising:

• a core engine including at least one high pressure spool assembly and a combustion chamber;
• a modified fan retrofittably mechanically coupled to a low pressure turbine that is in turn driven by hot gases generated by the core engine;
• wherein said modified fan is derived from or replaces an unmodified fan;
• wherein said modified fan is configured for generating a reduced bypass flow during operation of the turbofan engine relative to the unmodified fan, effective for said low pressure turbine to generate an excess shaft power above a baseline power required for driving said modified fan during operation of the turbofan engine;
• wherein the modified fan comprises a plurality of modified fan blades, wherein each said modified fan blade of said plurality of modified fan blades of the modified fan includes a corresponding inner blade portion having an inner radial portion geometry and an angle of attack;
• wherein said inner blade portion of each fan blade of the modified fan radially extends from a respective blade root to a radial position corresponding to the radial position of a leading edge of a casing of the core engine;
• and
• wherein said inner blade portion of each fan blade of the modified fan includes a respective modified blade tip radially spaced from a respective blade root by said radial position.

A turbofan engine, comprising:

• a core engine including at least one high pressure spool assembly and a combustion chamber;
• a modified fan retrofittably mechanically coupled to a low pressure turbine that is in turn driven by hot gases generated by the core engine;
• wherein said modified fan is derived from or replaces an unmodified fan;
• wherein said modified fan is configured for generating a reduced bypass flow during operation of the turbofan engine relative to the unmodified fan, effective for said low pressure turbine to generate an excess shaft power above a baseline power required for driving said modified fan during operation of the turbofan engine;
• wherein the modified fan comprises a plurality of modified fan blades, wherein each said modified fan blade of said plurality of modified fan blades of the modified fan includes a corresponding inner blade portion having an inner radial portion geometry and an angle of attack;
• wherein said inner blade portion of each fan blade of the modified fan radially extends from a respective blade root to a radial position corresponding to the radial position of a leading edge of a casing of the core engine;
• and
• an exhaust diffuser fitted to the core engine, wherein the exhaust diffuser is configured for reducing a core engine thrust.