TY - JOUR A1 - Finger, Felix A1 - Braun, Carsten A1 - Bil, Cees T1 - Impact of electric propulsion technology and mission requirements on the performance of VTOL UAVs JF - CEAS Aeronautical Journal N2 - One of the engineering challenges in aviation is the design of transitioning vertical take-off and landing (VTOL) aircraft. Thrust-borne flight implies a higher mass fraction of the propulsion system, as well as much increased energy consumption in the take-off and landing phases. This mass increase is typically higher for aircraft with a separate lift propulsion system than for aircraft that use the cruise propulsion system to support a dedicated lift system. However, for a cost–benefit trade study, it is necessary to quantify the impact the VTOL requirement and propulsion configuration has on aircraft mass and size. For this reason, sizing studies are conducted. This paper explores the impact of considering a supplemental electric propulsion system for achieving hovering flight. Key variables in this study, apart from the lift system configuration, are the rotor disk loading and hover flight time, as well as the electrical systems technology level for both batteries and motors. Payload and endurance are typically used as the measures of merit for unmanned aircraft that carry electro-optical sensors, and therefore the analysis focuses on these particular parameters. Y1 - 2018 U6 - http://dx.doi.org/10.1007/s13272-018-0352-x SN - 1869-5582 print SN - 1869-5590 online VL - 10 IS - 3 SP - 843 PB - Springer ER - TY - JOUR A1 - Finger, Felix A1 - Bil, Cees A1 - Braun, Carsten T1 - Initial Sizing Methodology for Hybrid-Electric General Aviation Aircraft JF - Journal of Aircraft Y1 - 2019 U6 - http://dx.doi.org/10.2514/1.C035428 SN - 1533-3868 VL - 57 IS - 2 SP - 245 EP - 255 ER - TY - CHAP A1 - Ludowicy, Jonas A1 - Rings, René A1 - Finger, Felix A1 - Braun, Carsten A1 - Bil, Cees T1 - Impact of Propulsion Technology Levels on the Sizing and Energy Consumption for Serial HybridElectric General Aviation Aircraft T2 - Asia Pacific International Symposium on Aerospace Technology. APISAT 2019 Y1 - 2019 ER - TY - CHAP A1 - Rings, René A1 - Ludowicy, Jonas A1 - Finger, Felix A1 - Braun, Carsten A1 - Bil, Cees T1 - Sensitivity Analysis of General Aviation Aircraft with Parallel Hybrid-Electric Propulsion Systems T2 - Asia Pacific International Symposium on Aerospace Technology. APISAT 2019 Y1 - 2019 ER - TY - CHAP A1 - Finger, Felix A1 - Braun, Carsten A1 - Bil, Cees T1 - Impact of Engine Failure Constraints on the Initial Sizing of Hybrid-Electric GA Aircraft T2 - AIAA Scitech 2019 Forum Y1 - 2019 U6 - http://dx.doi.org/10.2514/6.2019-1812 N1 - AIAA Scitech Forum, 2019; San Diego; United States; 7 January 2019 through 11 January 2019 ER - TY - CHAP A1 - Götten, Falk A1 - Finger, Felix A1 - Havermann, Marc A1 - Braun, Carsten A1 - Marino, Matthew A1 - Bil, Cees T1 - A highly automated method for simulating airfoil characteristics at low Reynolds number using a RANS - transition approach T2 - Deutscher Luft- und Raumfahrtkongress - DLRK 2019. Darmstadt, Germany Y1 - 2019 U6 - http://dx.doi.org/10.25967/490026 SP - 1 EP - 14 ER - TY - CHAP A1 - Finger, Felix A1 - Götten, Falk A1 - Braun, Carsten A1 - Bil, Cees T1 - Mass, Primary Energy, and Cost - The Impact of Optimization Objectives on the Initial Sizing of Hybrid-Electric General Aviation Aircraft T2 - Deutscher Luft- und Raumfahrtkongress 2019, DLRK 2019. Darmstadt, Germany Y1 - 2019 U6 - http://dx.doi.org/10.25967/490012 SP - 1 EP - 17 ER - TY - CHAP A1 - Götten, Falk A1 - Finger, Felix T1 - Conceptual Design of a Modular 150 kg Vertical Take-off and Landing Unmanned Aerial Vehicle T2 - Deutscher Luft- und Raumfahrtkongress - DLRK 2019. Darmstadt, Germany Y1 - 2019 SP - 1 EP - 10 ER - TY - CHAP A1 - Finger, Felix A1 - Götten, Falk A1 - Braun, Carsten A1 - Bil, C. T1 - On Aircraft Design Under the Consideration of Hybrid-Electric Propulsion Systems T2 - APISAT 2018: The Proceedings of the 2018 Asia-Pacific International Symposium on Aerospace Technology (APISAT 2018) N2 - A hybrid-electric propulsion system combines the advantages of fuel-based systems and battery powered systems and offers new design freedom. To take full advantage of this technology, aircraft designers must be aware of its key differences, compared to conventional, carbon-fuel based, propulsion systems. This paper gives an overview of the challenges and potential benefits associated with the design of aircraft that use hybrid-electric propulsion systems. It offers an introduction of the most popular hybrid-electric propulsion architectures and critically assess them against the conventional and fully electric propulsion configurations. The effects on operational aspects and design aspects are covered. Special consideration is given to the application of hybrid-electric propulsion technology to both unmanned and vertical take-off and landing aircraft. The authors conclude that electric propulsion technology has the potential to revolutionize aircraft design. However, new and innovative methods must be researched, to realize the full benefit of the technology. KW - Hybrid-electric aircraft KW - Aircraft design KW - Design rules KW - Green aircraft Y1 - 2019 SN - 978-981-13-3305-7 U6 - http://dx.doi.org/10.1007/978-981-13-3305-7_99 N1 - APISAT 2018 - Asia-Pacific International Symposium on Aerospace Technology. 16-18 October 2018. Chengdu, China. Lecture Notes in Electrical Engineering (LNEE, volume 459) SP - 1261 EP - 1272 PB - Springer CY - Singapore ER - TY - CHAP A1 - Götten, Falk A1 - Finger, Felix A1 - Braun, Carsten A1 - Havermann, Marc A1 - Bil, C. A1 - Gomez, F. T1 - Empirical Correlations for Geometry Build-Up of Fixed Wing Unmanned Air Vehicles T2 - APISAT 2018: The Proceedings of the 2018 Asia-Pacific International Symposium on Aerospace Technology (APISAT 2018) N2 - The results of a statistical investigation of 42 fixed-wing, small to medium sized (20 kg−1000 kg) reconnaissance unmanned air vehicles (UAVs) are presented. Regression analyses are used to identify correlations of the most relevant geometry dimensions with the UAV’s maximum take-off mass. The findings allow an empirical based geometry-build up for a complete unmanned aircraft by referring to its take-off mass only. This provides a bridge between very early design stages (initial sizing) and the later determination of shapes and dimensions. The correlations might be integrated into a UAV sizing environment and allow designers to implement more sophisticated drag and weight estimation methods in this process. Additional information on correlation factors for a rough drag estimation methodology indicate how this technique can significantly enhance the accuracy of early design iterations. KW - Unmanned Air Vehicle KW - Geometry KW - Correlations KW - Statistics KW - Drag Y1 - 2019 SN - 978-981-13-3305-7 U6 - http://dx.doi.org/10.1007/978-981-13-3305-7_109 N1 - APISAT 2018 - Asia-Pacific International Symposium on Aerospace Technology. 16-18 October 2018. Chengdu, China. Lecture Notes in Electrical Engineering (LNEE, volume 459) SP - 1365 EP - 1381 PB - Springer CY - Singapore ER - TY - CHAP A1 - Finger, Felix A1 - Götten, Falk A1 - Braun, Carsten A1 - Bil, Cees T1 - Cost Estimation Methods for Hybrid-Electric General Aviation Aircraft T2 - Asia Pacific International Symposium on Aerospace Technology. APISAT 2019 Y1 - 2019 SP - 1 EP - 13 ER - TY - CHAP A1 - Götten, Falk A1 - Finger, Felix A1 - Marino, Matthew A1 - Bil, Cees A1 - Havermann, Marc A1 - Braun, Carsten T1 - A review of guidelines and best practices for subsonic aerodynamic simulations using RANS CFD T2 - Asia-Pacific International Symposium on Aerospace Technology (APISAT), At Gold Coast, Australia, 04. - 06. Dezember 2019 Y1 - 2019 SN - 978-1-925627-40-4 ER - TY - CHAP A1 - Finger, Felix A1 - Khalsa, R. A1 - Kreyer, Jörg A1 - Mayntz, Joscha A1 - Braun, Carsten A1 - Dahmann, Peter A1 - Esch, Thomas A1 - Kemper, Hans A1 - Schmitz, O. A1 - Bragard, Michael T1 - An approach to propulsion system modelling for the conceptual design of hybrid-electric general aviation aircraft T2 - Deutscher Luft- und Raumfahrtkongress 2019, 30.9.-2.10.2019, Darmstadt N2 - In this paper, an approach to propulsion system modelling for hybrid-electric general aviation aircraft is presented. Because the focus is on general aviation aircraft, only combinations of electric motors and reciprocating combustion engines are explored. Gas turbine hybrids will not be considered. The level of the component's models is appropriate for the conceptual design stage. They are simple and adaptable, so that a wide range of designs with morphologically different propulsive system architectures can be quickly compared. Modelling strategies for both mass and efficiency of each part of the propulsion system (engine, motor, battery and propeller) will be presented. Y1 - 2019 ER - TY - JOUR A1 - Finger, Felix A1 - Götten, Falk T1 - Neue Ansätze für die Entwicklung von unbemannten Fluggeräten JF - Ingenieurspiegel N2 - Wie sieht das unbemannte Flugzeug von Übermorgen aus? Dieser Frage stellen sich Forscher an der Fachhochschule Aachen. Die weltweit rasant fortschreitende Entwicklung des Marktes für unbemannte Fluggeräte (UAVs - „Unmanned Aerial Vehicles“) bietet großes Potenzial für Wachstum und Wertschöpfung. Unbemannte fliegende Systeme können – für bestimmte Anwendungsgebiete – wesentlich günstiger, kleiner und effizienter ausgelegt werden als bemannte Lösungen. Dabei sind sich viele Unternehmen über das mögliche Potential dieser Technologie noch gar nicht bewusst. Y1 - 2019 SN - 1868-5919 N1 - Project: UAV Design VL - 2019 IS - 1 SP - 67 EP - 68 ER - TY - CHAP A1 - Götten, Falk A1 - Finger, Felix A1 - Havermann, Marc A1 - Braun, Carsten A1 - Marino, Matthew A1 - Bil, Cees T1 - Full Configuration Drag Estimation of Small-to-Medium Range UAVs and its Impact on Initial Sizing Optimization T2 - Deutscher Luft- und Raumfahrtkongress - DLRK 2020 Y1 - 2020 ER - TY - JOUR A1 - Finger, Felix A1 - Braun, Carsten A1 - Bil, Cees T1 - Comparative assessment of parallel-hybrid-electric propulsion systems for four different aircraft JF - Journal of Aircraft N2 - Until electric energy storage systems are ready to allow fully electric aircraft, the combination of combustion engine and electric motor as a hybrid-electric propulsion system seems to be a promising intermediate solution. Consequently, the design space for future aircraft is expanded considerably, as serial hybrid-electric, parallel hybrid-electric, fully electric, and conventional propulsion systems must all be considered. While the best propulsion system depends on a multitude of requirements and considerations, trends can be observed for certain types of aircraft and certain types of missions. This Paper provides insight into some factors that drive a new design toward either conventional or hybrid propulsion systems. General aviation aircraft, regional transport aircraft vertical takeoff and landing air taxis, and unmanned aerial vehicles are chosen as case studies. Typical missions for each class are considered, and the aircraft are analyzed regarding their takeoff mass and primary energy consumption. For these case studies, a high-level approach is chosen, using an initial sizing methodology. Only parallel-hybrid-electric powertrains are taken into account. Aeropropulsive interaction effects are neglected. Results indicate that hybrid-electric propulsion systems should be considered if the propulsion system is sized by short-duration power constraints. However, if the propulsion system is sized by a continuous power requirement, hybrid-electric systems offer hardly any benefit. Y1 - 2020 U6 - http://dx.doi.org/10.2514/1.C035897 SN - 1533-3868 VL - 57 IS - 5 PB - AIAA CY - Reston, Va. ER - TY - CHAP A1 - Hippe, Jonas A1 - Finger, Felix A1 - Götten, Falk A1 - Braun, Carsten T1 - Propulsion System Qualification of a 25 kg VTOL-UAV: Hover Performance of Single and Coaxial Rotors and Wind-Tunnel Experiments on Cruise Propellers T2 - Deutscher Luft- und Raumfahrtkongress - DLRK 2020 Y1 - 2020 ER - TY - JOUR A1 - Finger, Felix A1 - Götten, Falk A1 - Braun, Carsten A1 - Bil, Cees T1 - Mass, primary energy, and cost: the impact of optimization objectives on the initial sizing of hybrid-electric general aviation aircraft JF - CEAS Aeronautical Journal N2 - For short take-off and landing (STOL) aircraft, a parallel hybrid-electric propulsion system potentially offers superior performance compared to a conventional propulsion system, because the short-take-off power requirement is much higher than the cruise power requirement. This power-matching problem can be solved with a balanced hybrid propulsion system. However, there is a trade-off between wing loading, power loading, the level of hybridization, as well as range and take-off distance. An optimization method can vary design variables in such a way that a minimum of a particular objective is attained. In this paper, a comparison between the optimization results for minimum mass, minimum consumed primary energy, and minimum cost is conducted. A new initial sizing algorithm for general aviation aircraft with hybrid-electric propulsion systems is applied. This initial sizing methodology covers point performance, mission performance analysis, the weight estimation process, and cost estimation. The methodology is applied to the design of a STOL general aviation aircraft, intended for on-demand air mobility operations. The aircraft is sized to carry eight passengers over a distance of 500 km, while able to take off and land from short airstrips. Results indicate that parallel hybrid-electric propulsion systems must be considered for future STOL aircraft. Y1 - 2020 U6 - http://dx.doi.org/10.1007/s13272-020-00449-8 SN - 1869-5590 N1 - Corresponding author: Felix Finger VL - 2020 IS - 11 SP - 713 EP - 730 PB - Springer CY - Heidelberg ER - TY - CHAP A1 - Finger, Felix A1 - de Vries, Reynard A1 - Vos, Roelof A1 - Braun, Carsten A1 - Bil, Cees T1 - A comparison of hybrid-electric aircraft sizing methods T2 - AIAA Scitech 2020 Forum Y1 - 2020 U6 - http://dx.doi.org/10.2514/6.2020-1006 N1 - AIAA Scitech 2020 Forum, Driving aerospace solutions for global challenges, Orlando, 06. - 10. January 2020 ER - TY - CHAP A1 - Finger, Felix A1 - Braun, Carsten A1 - Bil, Cees T1 - Comparative assessment of parallel-hybrid-electric propulsion systems for four different aircraft T2 - AIAA SciTech Forum 2020, 06.01.2020 - 10.01.2020, Orlando Y1 - 2020 U6 - http://dx.doi.org/10.2514/6.2020-1502 ER -