Conceptual design of small aircraft with hybrid-electric propulsion systems

Abstract

Stakeholders envision the introduction of electric and hybrid-electric aircraft into operation by 2035. First developments of such aircraft have demonstrated that the existing technologies do not allow realization of hybrid-electric aircraft matching the performance of traditional aircraft with the same load factors. The major challenge of future hybrid-electric aircraft development is the considerable improvement of the energetic efficiencies. This paper evaluates the (i) problems and barriers (ii) emerging and required future technologies of effective hybrid-electric propulsion systems and (iii) adaptation of the aircraft conceptual design process for the development of hybrid-electric aircraft. The developed methodology is applied to the conceptual design of a small aircraft with hybrid-electric propulsion system. The results demonstrate that the adapted conceptual design methods with (i) constrains on mass fraction adapted to new technologies and solutions, (ii) constraints defined for energy fractions for flight mission legs, (iii) considering radically new elements and technologies in aircraft design and (iv) developing unconventional aircraft, aircraft operations may allow the development of small hybrid-electric aircraft with acceptable performance.