Overview and Preliminary Results of the Scalability Investigation of Hybrid Electric Concepts for Next-Generation Aircraft (SIENA) Project

This paper presents an overview and preliminary system architecture evaluation results of the project SIENA developed under the European Union Clean Sky 2 Program Thematic Topics. The ambition of the project is to accelerate the development of novel aircraft propulsion technologies by identification of technologies that are scalable across different aircraft categories. One of the main tasks within this process is the aircraft-level evaluation of the various system architecture and technology options. For this, a conceptual aircraft design software developed at Politecnico di Milano, and an aircraft on-board systems design and analysis method developed at Collins Aerospace Applied Research and Technology are combined. Utilizing these joint capabilities, the paper presents system architecture performance studies for two aircraft categories, a regional turboprop (ATR 72) and a short/medium-range turbofan (A320neo). The studies compare novel propulsion system concepts, for which kerosene is replaced with hydrogen as the main energy source on board, against traditional reference systems. In this context, two future technology scenarios are considered reflecting conservative and optimistic assumptions, respectively.