Conceptual studies of a future hybrid-electric regional aircraft
The research Bauhaus Luftfahrt conducted in recent years was continued and performed for several use cases on aircraft level. For a short-range aircraft seating 70 and 180 passengers, studies were performed to evaluate the feasibility and technical requirements for realisation of hybrid propulsion. The analysis of different morphologies led to an optimised power distribution between electric motors and conventional engines. In case of electric motors, high-temperature superconducting (HTS) motors were also considered. The required electric energy is provided by batteries placed within the aircraft. Thus, generators at the gas turbines for power generation could be spared. Following these considerations, a tri-fan was the consequent configuration, similar to the Boeing 727. The configuration consists of two conventional under-wing engines supported by an electric motor mounted in the aft tail.
The 180 passenger version operated with an electric power of 8.5 MW and a battery cell-level gravimetric specific energy of 940 Wh/kg. This resulted in a block fuel reduction of 15 %, compared to a conventional reference aircraft with the same technology standard. The design range of 1,100 nm (2,037 km) is close to that of modern regional aircraft. A further reduction of the design range to 900 nm (1,667 km) could further increase the fuel reduction potential to 20 %. However, the increased efficiency would come with a penalty of higher maximum take-off weight, compared to the conventional reference aircraft.
- Comparison between the A320, a year 2035 conventional and a year 2035 hybrid aircraft
- Impact of battery cell-level gravimetric specific energy on range and block fuel reduction for a hybrid-electric aircraft: Representation of the dependencies between block fuel reduction, range and battery cell-level gravimetric specific energy of the batteries for a hybrid-electric aircraft with 180 passengers using HTS motors. The diagram is based on an increase of accepted cash and additional operating costs of 10 %.