Browsing by Author "Geiß, Ingmar"

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Open Access
Sizing of the series hybrid-electric propulsion system of general aviation aircraft
(2020) Geiß, Ingmar; Voit-Nitschmann, Rudolf (Prof. Dipl.-Ing.)
Hybrid-electric aircraft possess the potential to reduce the CO2 emissions of general aviation aircraft. However, optimized propulsion systems are needed to leverage the advantages and lower the fuel consumption. In order to identify optimized designs, the characteristics of the individual propulsion elements are needed and suitable trends for mass, power and efficiency are required for modern propulsion components. Additionally, part load efficiency and altitude characteristics need to be investigated. The fuel consumption of an aircraft depends further on the aircraft mass and the aerodynamic drag. Hence, the influence of an increased propulsion system mass on the aircraft mass and the parasitic and induced drag is considered. Additionally, the required power reserve is determined to compensate a failure of a combustion engine or a battery pack during take-off. In a further investigation, the energy reserve is identified which is required after such component failure during cruise flight. The derived trends are implemented into a sizing program and optimized propulsion systems are determined for a 4-seat hybrid-electric aircraft with a cruise speed of 220 km/h as well as a 9-seat hybrid-electric aircraft with a cruise speed of 400 km/h.
Open Access
Technology selection for holistic analysis of hybrid-electric commuter aircraft
(2022) Zumegen, Clemens; Strathoff, Philipp; Stumpf, Eike; Wensveen, Jasper van; Rischmüller, Carsten; Hornung, Mirko; Geiß, Ingmar; Strohmayer, Andreas
Electric powertrains have different characteristics than conventional powertrains with combustion engines and require unconventional aircraft designs to evolve their full potential. Therefore, this paper describes a method to identify potential aircraft designs with electrified powertrains. Promising technology options in the fields of powertrain architecture, aerodynamic interactions, onboard systems and operating strategies were collected by the project partners of the LuFo project GNOSIS. The effect of the technology options on a commuter aircraft was evaluated in terms of global emissions ( CO2), local emissions ( NOXand noise) and operating costs. The evaluation considers an entry into service in 2025 and 2050 and is based on the reference aircraft Beechcraft 1900D. Literature review and simplified calculations enabled the evaluation of the aerodynamic interactions, systems and operating strategies. A preliminary aircraft design tool assessed the different powertrain architectures by introducing the two parameters ’power hybridization’ and ’power split’. Afterwards, compatible technology options were compiled into technology baskets and ranked using the shortest euclidean distance to the ideal solution and the farthest euclidean distance to the worst solution (Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method). An analysis of the CS 23 regulations leads to a high-wing design and excluded the partial turbo-electric powertrain architecture with the gas turbine in the aircraft tail. For 2025, a partial turbo-electric powertrain with two additional electric driven wingtip propellers was selected. A serial hybrid powertrain, which uses a gas turbine or fuel cell in combination with a battery, powers distributed electric propulsors at the wing leading edge in 2050. In both scenarios, the aircraft design includes an electric environmental control system, an electric driven landing gear and electro-hydraulic actuators for the primary flight control and landing gear.