Recently, a team composed of Boeing, GE, and Georgia Tech completed an 18-month study on future commercial airplane concepts under the NASA N+3 Program. The goal of the program is to explore revolutionary aircraft concepts aimed at entry into service date of 2030 and beyond, with aggressive noise, emissions, and fuel burn targets. The program looked at both subsonic and supersonic aircraft concepts. The Boeing-led team looked at five different subsonic concepts as part of the Subsonic, Ultra Green Aircraft Research (SUGAR) project. Concepts ranged from a conventional tube and wing design (SUGAR Free and Refined SUGAR) to a high span, strut-braced wing aircraft (SUGAR High and SUGAR Volt), and a hybrid wing body configuration (SUGAR Ray). To read more about Boeing’s technology research and the future of aircraft design, click here.
While not all concepts met the ambitious goal set by NASA, the SUGAR Volt concept, which adds an electric battery gas turbine hybrid propulsion system, can reduce fuel burn by greater than 70%. It also reduces overall energy use by 55% when battery energy is included. With the fuel burn improvement, the aircraft has an added benefit of large reductions of CO2 and nitrous oxide emissions.
What’s preventing engineers from designing such aircraft today? One major challenge is battery technology. While there are rapid advancements in battery technology, a level of energy density suitable for aerospace application is still years away. Will a hybrid electric open rotor propulsion be the game changing technology the industry is seeking? We hope so. There have been many innovative aircraft concepts that were not adopted due to either the infrastructural or operational constraints. As the price of fuel continues to increase, the industry will hopefully be more acceptable to these innovations.