TY - CHAP A1 - Blome, Hans-Joachim T1 - Über die kulturelle Bedeutung der Raumfahrt T2 - Überleben im Weltraum. Auf dem Weg zu neuen Grenzen. 21. Berliner Kolloquium der Daimler und Benz Stiftung 24. Mai 2017 Y1 - 2018 SP - 5 EP - 5 ER - TY - CHAP A1 - Finger, Felix A1 - Braun, Carsten A1 - Bil, Cees T1 - Case studies in initial sizing for hybrid-electric general aviation aircraft T2 - 2018 AIAA/IEEE Electric Aircraft Technologies Symposium, Cincinnati, Ohio Y1 - 2018 U6 - http://dx.doi.org/10.2514/6.2018-5005 ER - 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 - CHAP A1 - Finger, Felix A1 - Götten, Falk A1 - Braun, Carsten T1 - Initial Sizing for a Family of Hybrid-Electric VTOL General Aviation Aircraft T2 - 67. Deutscher Luft- und Raumfahrtkongress 2018 Y1 - 2018 ER - TY - JOUR A1 - Funke, Harald A1 - Beckmann, Nils A1 - Keinz, Jan A1 - Abanteriba, Sylvester T1 - Comparison of Numerical Combustion Models for Hydrogen and Hydrogen-Rich Syngas Applied for Dry-Low-Nox-Micromix-Combustion JF - Journal of Engineering for Gas Turbines and Power N2 - The Dry-Low-NOx (DLN) Micromix combustion technology has been developed as low emission combustion principle for industrial gas turbines fueled with hydrogen or syngas. The combustion process is based on the phenomenon of jet-in-crossflow-mixing (JICF). Fuel is injected perpendicular into the air-cross-flow and burned in a multitude of miniaturized, diffusion-like flames. The miniaturization of the flames leads to a significant reduction of NOx emissions due to the very short residence time of reactants in the flame. In the Micromix research approach, computational fluid dynamics (CFD) analyses are validated toward experimental results. The combination of numerical and experimental methods allows an efficient design and optimization of DLN Micromix combustors concerning combustion stability and low NOx emissions. The paper presents a comparison of several numerical combustion models for hydrogen and hydrogen-rich syngas. They differ in the complexity of the underlying reaction mechanism and the associated computational effort. The performance of a hybrid eddy-break-up (EBU) model with a one-step global reaction is compared to a complex chemistry model and a flamelet generated manifolds (FGM) model, both using detailed reaction schemes for hydrogen or syngas combustion. Validation of numerical results is based on exhaust gas compositions available from experimental investigation on DLN Micromix combustors. The conducted evaluation confirms that the applied detailed combustion mechanisms are able to predict the general physics of the DLN-Micromix combustion process accurately. The FGM method proved to be generally suitable to reduce the computational effort while maintaining the accuracy of detailed chemistry. Y1 - 2018 U6 - http://dx.doi.org/10.1115/1.4038882 SN - 0742-4795 N1 - Article number 081504; Paper No: GTP-17-1567 VL - 140 IS - 8 PB - ASME CY - New York, NY ER - TY - CHAP A1 - Grundmann, Jan Thimo A1 - Bauer, Waldemar A1 - Biele, Jens A1 - Boden, Ralf A1 - Ceriotti, Matteo A1 - Cordero, Federico A1 - Dachwald, Bernd A1 - Dumont, Etienne A1 - Grimm, Christian D. A1 - Herčík, David A1 - Ho, Tra-Mi A1 - Jahnke, Rico A1 - Koch, Aaron D A1 - Koncz, Alexander A1 - Krause, Christian A1 - Lange, Caroline A1 - Lichtenheldt, Roy A1 - Maiwald, Volker A1 - Mikschl, Tobias A1 - Mikulz, Eugen A1 - Montenegro, Sergio A1 - Pelivan, Ivanka A1 - Peloni, Alessandro A1 - Quantius, Dominik A1 - Reershemius, Siebo A1 - Renger, Thomas A1 - Riemann, Johannes A1 - Ruffer, Michael A1 - Sasaki, Kaname A1 - Schmitz, Nicole A1 - Seboldt, Wolfgang A1 - Seefeldt, Patric A1 - Spietz, Peter A1 - Spröwitz, Tom A1 - Sznajder, Maciej A1 - Tardivel, Simon A1 - Tóth, Norbert A1 - Wejmo, Elisabet A1 - Wolff, Friederike A1 - Ziach, Christian T1 - Small spacecraft based multiple near-earth asteroid rendezvous and landing with near-term solar sails and ‘Now-Term ‘technologies T2 - 69 th International Astronautical Congress (IAC) N2 - Physical interaction with small solar system bodies (SSSB) is the next step in planetary science, planetary in-situ resource utilization (ISRU), and planetary defense (PD). It requires a broader understanding of the surface properties of the target objects, with particular interest focused on those near Earth. Knowledge of composition, multi-scale surface structure, thermal response, and interior structure is required to design, validate and operate missions addressing these three fields. The current level of understanding is occasionally simplified into the phrase, ”If you’ve seen one asteroid, you’ve seen one asteroid”, meaning that the in-situ characterization of SSSBs has yet to cross the threshold towards a robust and stable scheme of classification. This would enable generic features in spacecraft design, particularly for ISRU and science missions. Currently, it is necessary to characterize any potential target object sufficiently by a dedicated pre-cursor mission to design the mission which then interacts with the object in a complex fashion. To open up strategic approaches, much broader in-depth characterization of potential target objects would be highly desirable. In SSSB science missions, MASCOT-like nano-landers and instrument carriers which integrate at the instrument level to their mothership have met interest. By its size, MASCOT is compatible with small interplanetary missions. The DLR-ESTEC Gossamer Roadmap Science Working Groups‘ studies identified Multiple Near-Earth asteroid (NEA) Rendezvous (MNR) as one of the space science missions only feasible with solar sail propulsion. The Solar Polar Orbiter (SPO) study showed the ability to access any inclination, theDisplaced-L1 (DL1) mission operates close to Earth, where objects of interest to PD and for ISRU reside. Other studies outline the unique capability of solar sails to provide access to all SSSB, at least within the orbit of Jupiter, and significant progress has been made to explore the performance envelope of near-term solar sails for MNR. However, it is difficult for sailcraft to interact physically with a SSSB. We expand and extend the philosophy of the recently qualified DLR Gossamer solar sail deployment technology using efficient multiple sub-spacecraft integration to also include landers for one-way in-situ investigations and sample-return missions by synergetic integration and operation of sail and lander. The MASCOT design concept and its characteristic features have created an ideal counterpart for thisand has already been adapted to the needs of the AIM spacecraft, former part of the NASA-ESA AIDA missionDesigning the 69th International Astronautical Congress (IAC), Bremen, Germany, 1-5 October 2018. IAC-18-F1.2.3 Page 2 of 17 combined spacecraft for piggy-back launch accommodation enables low-cost massively parallel access to the NEA population. KW - multiple NEA rendezvous KW - solar sail KW - GOSSAMER-1 KW - MASCOT KW - small spacecraft Y1 - 2018 N1 - 69th International Astronautical Congress (IAC), Bremen, Germany, 1-5 October 2018. https://www.bho-legal.com/1-5-october-2018-69th-international-astronautical-congress-2018-in-bremen-germany/ SP - 1 EP - 18 ER - TY - CHAP A1 - Grundmann, Jan Thimo A1 - Bauer, Waldemar A1 - Biele, Jens A1 - Boden, Ralf A1 - Ceriotti, Matteo A1 - Cordero, Federico A1 - Dachwald, Bernd A1 - Dumont, Etienne A1 - Grimm, Christian A1 - Herčík, David A1 - Herique, Alain A1 - Ho, Tra-Mi A1 - Jahnke, Rico A1 - Koch, Aaron A1 - Kofman, Wlodek A1 - Koncz, Alexander A1 - Krause, Christian A1 - Lange, Caroline A1 - Lichtenheldt, Roy A1 - Maiwald, Volker A1 - Mikschl, Tobias A1 - Mikulz, Eugen A1 - Montenegro, Sergio A1 - Pelivan, Ivanka A1 - Peloni, Alessandro A1 - Plettemeier, Dirk A1 - Quantius, Dominik A1 - Reershemius, Siebo A1 - Renger, Thomas A1 - Riemann, Johannes A1 - Ruffer, Michael A1 - Sasaki, Kaname A1 - Schmitz, Nicole A1 - Seboldt, Wolfgang A1 - Seefeldt, Patric A1 - Spietz, Peter A1 - Spröwitz, Tom A1 - Sznajder, Maciej A1 - Tardivel, Simon A1 - Toth, Norbert A1 - Wejmo, Elisabet A1 - Wolff, Friederike A1 - Ziach, Christian T1 - Efficient massively parallel prospection for ISRU by multiple near-earth asteroid rendezvous using near-term solar sails and'now-term'small spacecraft solutions T2 - 2nd Asteroid Science Intersections with In-Space Mine Engineering – ASIME 2018 N2 - Physical interaction with small solar system bodies (SSSB) is key for in-situ resource utilization (ISRU). The design of mining missions requires good understanding of SSSB properties, including composition, surface and interior structure, and thermal environment. But as the saying goes "If you've seen one asteroid, you've seen one Asteroid": Although some patterns may begin to appear, a stable and reliable scheme of SSSB classification still has to be evolved. Identified commonalities would enable generic ISRU technology and spacecraft design approaches with a high degree of re-use. Strategic approaches require much broader in-depth characterization of the SSSB populations of interest to the ISRU community. The DLR-ESTEC GOSSAMER Roadmap Science Working Groups identified target-flexible Multiple Near-Earth asteroid (NEA) Rendezvous (MNR) as one of the missions only feasible with solar sail propulsion, showed the ability to access any inclination and a wide range of heliocentric distances as well as continuous operation close to Earth's orbit where low delta-v objects reside. Y1 - 2018 N1 - 2nd Asteroid Science Intersections with In-Space Mine Engineering – ASIME 2018 16-17 April 2018, Belval, Luxembourg SP - 1 EP - 33 ER - TY - CHAP A1 - Grundmann, Jan Thimo A1 - Bauer, Waldemar A1 - Borchers, Kai A1 - Dumont, Etienne A1 - Grimm, Christian D. A1 - Ho, Tra-Mi A1 - Jahnke, Rico A1 - Lange, Caroline A1 - Maiwald, Volker A1 - Mikulz, Eugen A1 - Quantius, Dominik A1 - Reershemius, Siebo A1 - Renger, Thomas A1 - Riemann, Johannes A1 - Sasaki, Kaname A1 - Seefeldt, Patric A1 - Spietz, Peter A1 - Spröwitz, Tom A1 - Toth, Norbert A1 - Wejmo, Elisabet A1 - Biele, Jens A1 - Krause, Christian A1 - Cerotti, Matteo A1 - Peloni, Alessandro A1 - Dachwald, Bernd T1 - Small Spacecraft Solar Sailing for Small Solar System Body Multiple Rendezvous and Landing T2 - 2018 IEEE Aerospace Conference : 3-10 March 2018 Y1 - 2018 SN - 978-1-5386-2014-4 ER - TY - JOUR A1 - Götten, Falk A1 - Finger, Felix A1 - Havermann, Marc A1 - Braun, Carsten A1 - Gomez, Francisco A1 - Bill, C. T1 - On the flight performance impact of landing gear drag reduction methods for unmanned air vehicles JF - Deutscher Luft- und Raumfahrtkongress 2018 N2 - The flight performance impact of three different landing gear configurations on a small, fixed-wing UAV is analyzed with a combination of RANS CFD calculations and an incremental flight performance algorithm. A standard fixed landing gear configuration is taken as a baseline, while the influence of retracting the landing gear or applying streamlined fairings is investigated. A retraction leads to a significant parasite drag reduction, while also fairings promise large savings. The increase in lift-to-drag ratio is reduced at high lift coefficients due to the influence of induced drag. All configurations are tested on three different design missions with an incremental flight performance algorithm. A trade-off study is performed using the retracted or faired landing gear's weight increase as a variable. The analysis reveals only small mission performance gains as the aerodynamic improvements are negated by weight penalties. A new workflow for decision-making is presented that allows to estimate if a change in landing gear configuration is beneficial for a small UAV. Y1 - 2018 U6 - http://dx.doi.org/10.25967/480058 PB - DGLR CY - Bonn ER - TY - CHAP A1 - Götten, Falk A1 - Havermann, Marc A1 - Braun, Carsten A1 - Gomez, Francisco A1 - Bil, Cees T1 - On the Applicability of Empirical Drag Estimation Methods for Unmanned Air Vehicle Design Read More: https://arc.aiaa.org/doi/10.2514/6.2018-3192 T2 - 2018 Aviation Technology, Integration, and Operations Conference, AIAA AVIATION Forum Y1 - 2018 U6 - http://dx.doi.org/10.2514/6.2018-3192 SN - 1533-385X N1 - AIAA 2018-3192 SP - Article 3192 ER -