A challenge in civil aviation future propulsion systems is expected to be the integration with the airframe, coming as a result of increasing bypass ratio or above wing installations for noise mitigation. The resulting highly distorted inlet flows to the engine, make a clear demand for advanced gas turbine performance prediction models. Since the dawn of jet engine several models have been proposed and the present work comes to add a model that combines two well established compressor performance methods in order to create a quasi three dimensional representation of the fan of a modern turbofan. A streamline curvature model is coupled to a parallel compressor method, covering radial and circumferential directions respectively. Model testing has shown a close agreement to experimental data, making it a good candidate for assessing the loss of surge margin on a high bypass ratio turbofan, semi-embedded on the upper surface of a broad wing airframe
