06 Fakultät Luft- und Raumfahrttechnik und Geodäsie
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/7
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Item 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, AndreasElectric 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.Item Open Access High-performance properties of an aerospace epoxy resin loaded with carbon nanofibers and glycidyl polyhedral oligomeric silsesquioxane(2022) Guadagno, Liberata; Pantelakis, Spiros; Strohmayer, Andreas; Raimondo, MarialuigiaThis paper proposes a new multifunctional flame retardant carbon nanofiber/glycidyl polyhedral oligomeric silsesquioxane (GPOSS) epoxy formulation specially designed for lightweight composite materials capable of fulfilling the ever-changing demands of the future aerospace industry. The multifunctional resin was designed to satisfy structural and functional requirements. In particular, this paper explores the advantages deriving from the combined use of GPOSS and CNFs (short carbon nanofibers) to obtain multifunctional resins. The multifunctional material was prepared by incorporating in the epoxy matrix heat-treated carbon nanofibers (CNFs) at the percentage of 0.5 wt% and GPOSS compound at 5 wt% in order to increase the mechanical performance, electrical conductivity, thermal stability and flame resistance property of the resulting nanocomposite. Dynamic mechanical analysis (DMA) shows that the values of the Storage Modulus (S.M.) of the resin alone and the resin containing solubilized GPOSS nanocages are almost similar in a wide range of temperatures (from 30 °C to 165 °C). The presence of CNFs, in the percentage of 0.5 wt%, determines an enhancement in the S.M. of 700 MPa from −30 °C to 180 °C with respect to the resin matrix and the resin/GPOSS systems. Hence, a value higher than 2700 MPa is detected from 30 °C to 110 °C. Furthermore, the electrical conductivity of the sample containing both GPOSS and CNFs reaches the value of 1.35 × 10−1 S/m, which is a very satisfying value to contrast the electrical insulating property of the epoxy systems. For the first time, TUNA tests have been performed on the formulation where the advantages of GPOSS and CNFs are combined. TUNA investigation highlights an electrically conductive network well distributed in the sample. The ignition time of the multifunctional nanocomposite is higher than that of the sample containing GPOSS alone of about 35%.Item Open Access In-flight lift and drag estimation of an unmanned propeller-driven aircraft(2021) Bergmann, Dominique Paul; Denzel, Jan; Pfeifle, Ole; Notter, Stefan; Fichter, Walter; Strohmayer, AndreasThe high-power density and good scaling properties of electric motors enable new propulsion arrangements and aircraft configurations. This results in distributed propulsion systems allowing to make use of aerodynamic interaction effects between individual propellers and the wing of the aircraft, improving flight performance and thus reducing in-flight emissions. In order to systematically analyze these effects, an unmanned research platform was designed and built at the University of Stuttgart. As the aircraft is being used as a testbed for various flight performance studies in the field of distributed electric propulsion, a methodology for precise identification of its performance characteristics is required. One of the main challenges is the determination of the total drag of the aircraft to be able to identify an exact drag and lift polar in flight. For this purpose, an on-board measurement system was developed which allows for precise determination of the thrust of the aircraft which equals the total aerodynamic drag in steady, horizontal flight. The system has been tested and validated in flight using the unmanned free-flight test platform. The article provides an overview of the measuring system installed, discusses its functionality and shows results of the flight tests carried out.Item Open Access Hydrogen-powered aviation : design of a hybrid-electric regional aircraft for entry into service in 2040(2023) Eissele, Jona; Lafer, Stefan; Mejía Burbano, Cristian; Schließus, Julian; Wiedmann, Tristan; Mangold, Jonas; Strohmayer, AndreasOver the past few years, the rapid growth of air traffic and the associated increase in emissions have created a need for sustainable aviation. Motivated by these challenges, this paper explores how a 50-passenger regional aircraft can be hybridized to fly with the lowest possible emissions in 2040. In particular, the use of liquid hydrogen in this aircraft is an innovative power source that promises to reduce CO2 and NOx emissions to zero. Combined with a fuel-cell system, the energy obtained from the liquid hydrogen can be used efficiently. To realize a feasible concept in the near future considering the aspects of performance and security, the system must be hybridized. In terms of maximized aircraft sustainability, this paper analyses the flight phases and ground phases, resulting in an aircraft design with a significant reduction in operating costs. Promising technologies, such as a wingtip propeller and electric green taxiing, are discussed in this paper, and their potential impacts on the future of aviation are highlighted. In essence, the hybridization of regional aircraft is promising and feasible by 2040; however, more research is needed in the areas of fuel-cell technology, thermal management and hydrogen production and storage.Item Open Access Influence of electric wing tip propulsion on the sizing of the vertical stabilizer and rudder in preliminary aircraft design(2023) Albrecht, Alexander; Bender, Andreas; Strathoff, Philipp; Zumegen, Clemens; Stumpf, Eike; Strohmayer, AndreasDuring preliminary aircraft design, the vertical tail sizing is conventionally conducted by the use of volume coefficients. These represent a statistical approach using existing configurations’ correlating parameters, such as wing span and lever arm, to size the empennage. For a more detailed analysis with regard to control performance, the vertical tail size strongly depends on the critical loss of thrust assessment. This consideration increases in complexity for the design of the aircraft using wing tip propulsion systems. Within this study, a volume coefficient-based vertical tail plane sizing is compared to handbook methods and the possibility to reduce the necessary vertical stabilizer size is assessed with regard to the position of the engine integration and their interconnection. Two configurations, with different engine positions, of a hybrid-electric 19-seater aircraft, derived from the specifications of a Beechcraft 1900D, are compared. For both configurations two wiring options are assessed with regard to their impact on aircraft level for a partial loss of thrust. The preliminary aircraft design tool MICADO is used to size the four aircraft and propulsion system configurations using fin volume coefficients. These results are subsequently amended by handbook methods to resize the vertical stabilizer and update the configurations. The results in terms of, e.g., operating empty mass and mission fuel consumption, are compared to the original configurations without the optimized vertical stabilizer. The findings support the initial idea that the connection of the electric engines on the wing tips to their respective power source has a significant effect on the resulting torque around the yaw axis and the behaviour of the aircraft in case of a power train failure, as well as on the empty mass and trip fuel. For only one out of the four different aircraft designs and wiring configurations investigated it was possible to decrease the fin size, resulting in a 53.7% smaller vertical tail and a reduction in trip fuel of 4.9%, compared to the MICADO design results for the original fin volume coefficient.Item Open Access Integration of propelled yaw control on wing tips : a practical approach to the Icaré solar-powered glider(2022) Schneider, Johannes; Frangenberg, Michael; Notter, Stefan; Scholz, Werner; Fichter, Walter; Strohmayer, AndreasIn this practical approach to distributed propulsion, the solar-powered manned motorglider icaré 2 has been used as a testbed for wingtip propulsion. The large wingspan and slow cruising speed of icaré 2 are highly suitable to assess the influence and potential of propellers at the wingtips for yaw control. The paper describes the work of a multidisciplinary team consisting of researchers, engineers, pilots and students, starting from the initial idea to use propellers at the wingtips of icaré 2 up to the actual flight test campaign. First, the design and development of the modular wingtip pods are described to house the propeller, electric motor, battery and further sensors and control systems. Furthermore, the modifications required for integrating the wingtip pods on the aircraft itself are outlined and the electrical and mechanical interfaces are defined and described. To obtain a permit to fly for the new configuration of the aircraft, several tests on system level of the wingtip pods needed to be conducted and documented for the authorities. Finally, the flight test campaigns carried out to date are outlined and described including the planning, lessons learned and results.Item Open Access Refueling of LH2 aircraft - assessment of turnaround procedures and aircraft design implication(2022) Mangold, Jonas; Silberhorn, Daniel; Moebs, Nicolas; Dzikus, Niclas; Hoelzen, Julian; Zill, Thomas; Strohmayer, AndreasItem Open Access Editorial - special issue “9th EASN International Conference on Innovation in Aviation & Space”(2021) Pantelakis, Spiros; Strohmayer, AndreasItem Open Access Analysis leading to the design of a hybrid gas-electric multi-engine testbed(2023) Kuśmierek, Agata; Grzeszczyk, Rafał; Strohmayer, Andreas; Galiński, CezaryGiven the increase in air traffic, the main challenges in aircraft design are in-flight emissions and noise heard by the community. These problems have thus far been solved by incremental improvements in aerodynamics, engine technology and operation. To dramatically reduce aviation’s carbon footprint towards an environmentally friendly air transport system, alternative propulsion concepts are one of the promising areas of research and first applications. In this context, the goal of integrating a hybrid-electric powertrain with a suitable airframe is to increase efficiency while reducing in-flight emissions, reduce noise for the community, drive down direct operating costs and increase reliability. This article presents an inexpensive approach to testing small, manned aircraft with a hybrid fuel-electric propulsion system. First, the design assumptions of the research flying platform are presented. Next, modifications of the existing two-seater glider are analyzed. These modifications are necessary to fit the fuel–electric hybrid propulsion system. The analysis allows us to select the elements of an appropriate hybrid electric system. It also shows that this type of small experimental propulsion system can be mounted on a two-seater aerobatic glider without significant structural modifications and still comply with the most important points of the Certification Standard-22. Finally, the design of the ground test stand for the propulsion system is described. It is believed that a thorough examination of the propulsion system on the ground will reveal both the advantages and disadvantages of the system. This should facilitate the successful installation of the system under study on a flying aircraft.Item Open Access Editorial - special issue “10th EASN International Conference on Innovation in Aviation & Space to the Satisfaction of the European Citizens”(2021) Guadagno, Liberata; Pantelakis, Spiros; Strohmayer, Andreas