Aerodynamics issues related to hybrid electric propulsion

The use of hybrid electric propulsion for commercial transport aircraft could be strongly limited by available battery power density. Nevertheless, specific characteristics of electric motors could be used to design non-conventional configurations using innovative solutions such as distributed electrical propulsion (DEP), wing-tip propeller and boundary-layer ingestion. All these aspects have to be taken into account in the preliminary design phase. Preliminary design tools are based on a classical approach and are unable to evaluate these effects. Extensive CFD has been performed and used to derive simplified methods to simulate DEP, tip propeller and BLI in the preliminary design.