An aircraft propulsion system nacelle

An aircraft propulsion system (100) has an engine assembly (110) having an axis of rotation (124), a fan assembly (120) operatively connected to the engine assembly (110) and comprising a plurality of fan blades (122) arranged circumferentially around the axis of rotation (124) and a monolithic nacelle assembly (130) which circumferentially encloses the fan assembly (120). The propulsion system (100) has a ratio of fan assembly outer diameter (128) to nacelle assembly outer diameter (138) of at least 0.87. As a result, the propulsion system (100) provides for a significantly larger fan assembly outer diameter (128) for a given nacelle assembly outer diameter (138) than a conventional prior art turbofan engine, thereby increasing the specific power output or the bypass ratio of the propulsion system (100), which will result in improved propulsive efficiency without an increase in nacelle drag.