Turbofan arrangement

A bypass turbofan engine comprising a first propulsion system and a second propulsion system, the first propulsion system comprising a first fan rotor, a core engine, a first low pressure turbine and a first fan shaft drivingly connecting the first turbine and the first fan rotor, the second propulsion system comprising a second fan shaft drivingly connecting to a second fan rotor, the second fan shaft being drivingly connected to the first propulsion system characterised in that the first and second shafts are not coaxial with one another and wherein the engine further comprises a nacelle defining a bypass duct, the bypass duct comprising an inlet and a bypass exhaust nozzle, the bypass duct substantially surrounds and extends downstream of a fan rotor and transitions from a substantially circular cross-section to a part-ring shaped cross-section at its exhaust nozzle.