Recent developments about hybrid propelled aircraft: a short review

Over the last decades, the rapid growth of the consumption of fossil fuel has generated an increased need for energy sustainability. The negative impact on the environment and now, as a global society, the dependence on fossil fuel have been questioned. For contrasting these adverse effects, NASA calls on the aeronautic industry to reduce aircraft fuel burn by 70% by 2025 in their N+3 concepts. Following high-profile government and industry studies, electric aircraft propulsion has emerged as an important research topic, this includes all-electric, hybrid electric, and turboelectric architectures. The paper overviews the recent state-of-art about the innovative propulsion systems exploring the operating logic, their technological requirements, the ongoing research, and development in all the components necessary to make this technological change a feasible option for the future of passenger flight. It will be also reported the existing commercial products, prototypes, demonstrators for having a precise picture of the situation.