Methodology for Sizing and Performance Assessment of Hybrid Energy Aircraft

The Strategic Research and Innovation Agenda and NASA N+3 goals have set new challenges for the aeronautical community via declaration of dramatic efficiency improvements. Because further evolutionary improvements do not appear to be sufficient, envisioning disruptive technologies turn out to be essential to reach the set of future targets. The design of innovative integrated energy-power systems is certainly a major promising element as can be shown by the increasing interest toward hybrid energy and universally electric aircraft. The consideration of these new types of aircraft represents a new challenge for conventional aircraft sizing and performance methods. As an extension of the conventional methods used for fuel-energy aircraft, a sizing and performance methodology for hybrid-energy aircraft is proposed. A design study of a battery and fuel hybrid-energy single-aisle retrofit is conducted to demonstrate the methodology and to analyze the implications of the associated new design variables on the sizing and performance. The benchmark against a conventional reference aircraft shows a potential block fuel-burn reduction up to 16% for a 900n mile off-design mission stage length (using a mix of fuel energy to electrical energy of 82:18%). Clean sheet designs will be part of future work to assess the full potential of hybrid-energy aircraft.