OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. This is an author-deposited version published in : http://oatao.univ-toulouse.fr/ Eprints ID : 16020 LAPLACE(CNRS/INPT/UPS), Université de Toulouse, 31071, Toulouse, FranceThis article assesses the benefits of hybridization within the regional aircraft scale using a conventional twin-turbo propeller aircraft as reference. For a fair comparison, this reference aircraft was designed assuming a 2035 technology level. The propulsion system of the reference aircraft is analyzed along the mission and the phases of flight with low efficiencies are highlighted. Then the potential benefits of new power management through the use of secondary power generation systems but also through the variation of the size of prime movers are presented and discussed. In particular, the effect of the gas turbine size on its efficiency is studied. Finally, the article focuses on aerodynamic improvements enabled by new propeller or fan integrations and the associated concepts such as differential thrust, blown wing and boundary layer ingestion. For each topic, simplified analyses provide estimated potential of energy saving. These results can be used as indicators for selecting the most promising hybrid architecture concepts for a regional aircraft. Nomenclature

This is an author-deposited version published in: http://oatao.univ-toulouse.fr/ Eprints ID: 16687Open Archive Toulouse Archive Ouverte (OATAO) OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. Abstract-This article assesses the potential benefits of transient energy storage for a hybrid regional aircraft. The mission profile of a reference aircraft is analyzed according to energetic intermittence and the results are compared to typical figures for cars, trains, and ships. Also, the opportunity of recovering energy in descent and during landing is studied. This article shows that energy saving potential brought by transient energy storage is much smaller than for ground-based transportation. In addition, energy recovering does not bring benefit on a hybrid aircraft in normal operation. Nevertheless, the best energy management strategies in descent are highlighted and the use of a hybrid propulsion system in this phase shows significant potential energy savings. Finally, the article addresses other strategies enabled by hybrid propulsion to improve the aircraft energy efficiency. To cite this version: