Conceptual Design of a Hybrid-Electric Aircraft Based on a Dornier 328 Demonstrator

Air travel contributed 3.5% to global warming in 2020, with a rising tendency. Only one third of the climate impact is caused by CO2. Other exhaust gases that cause harm to the climate are nitrogen oxides, soot, and water vapor, creating contrails with a negative impact on earth’s albedo. Hence, it is important to reduce any type of emission. As the effects of global climate change become an unneglectable threat to society, calls for quick changes become prominent. Recognizing the need for disruptive changes in air transport, the LuFo-project 328eHY-TECH was initiated to investigate the potential of regional hybrid-electric aircraft. This article focuses on conceptual aircraft design. An aircraft resembling the D328eco is modeled as a baseline aircraft, on which the sizing of the hybrid-electric propulsion systems is performed. As aircraft are mostly operated on a typical mission, which is shorter than the design mission, a distance of 400 nm is found to be a feasible range for this regional aircraft. In a conducted range study, the potential of state-of-the-art battery properties is being investigated and found to be insufficient. Subsequently conducted trade-off studies show that a 104 kW horsepower electric motor and a battery of 1.8 kWh/kg are needed to save 5% block fuel on a mission with 40 passengers of 95 kg over a distance of 400 nm. It is concluded that changing solely the propulsion system will not yield feasible aircraft designs in the near and midterm future.