@inproceedings{FingerKhalsaKreyeretal.2019,
  author    = {Finger, Felix and Khalsa, R. and Kreyer, J{\"o}rg and Mayntz, Joscha and Braun, Carsten and Dahmann, Peter and Esch, Thomas and Kemper, Hans and Schmitz, O. and Bragard, Michael},
  title     = {An approach to propulsion system modelling for the conceptual design of hybrid-electric general aviation aircraft},
  series = {Deutscher Luft- und Raumfahrtkongress 2019, 30.9.-2.10.2019, Darmstadt},
  booktitle = {Deutscher Luft- und Raumfahrtkongress 2019, 30.9.-2.10.2019, Darmstadt},
  pages     = {15 Seiten},
  year      = {2019},
  abstract  = {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.},
  language  = {en}
}
@article{FingerBraunBil2018,
  author    = {Finger, Felix and Braun, Carsten and Bil, Cees},
  title     = {Impact of electric propulsion technology and mission requirements on the performance of VTOL UAVs},
  series = {CEAS Aeronautical Journal},
  volume    = {10},
  journal   = {CEAS Aeronautical Journal},
  number    = {3},
  publisher = {Springer},
  issn      = {1869-5582 print},
  doi       = {10.1007/s13272-018-0352-x},
  pages     = {843},
  year      = {2018},
  abstract  = {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.},
  language  = {en}
}
@article{FunkeBeckmannAbanteriba2019,
  author    = {Funke, Harald and Beckmann, Nils and Abanteriba, Sylvester},
  title     = {An overview on dry low NOx micromix combustor development for hydrogen-rich gas turbine applications},
  series = {International Journal of Hydrogen Energy},
  volume    = {44},
  journal   = {International Journal of Hydrogen Energy},
  number    = {13},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0360-3199},
  doi       = {10.1016/j.ijhydene.2019.01.161},
  pages     = {6978 -- 6990},
  year      = {2019},
  language  = {en}
}
@inproceedings{FingerdeVriesVosetal.2020,
  author    = {Finger, Felix and de Vries, Reynard and Vos, Roelof and Braun, Carsten and Bil, Cees},
  title     = {A comparison of hybrid-electric aircraft sizing methods},
  series = {AIAA Scitech 2020 Forum},
  booktitle = {AIAA Scitech 2020 Forum},
  doi       = {10.2514/6.2020-1006},
  pages     = {31 Seiten},
  year      = {2020},
  abstract  = {The number of case studies focusing on hybrid-electric aircraft is steadily increasing, since these configurations are thought to lead to lower operating costs and environmental impact than traditional aircraft. However, due to the lack of reference data of actual hybrid-electric aircraft, in most cases, the design tools and results are difficult to validate. In this paper, two independently developed approaches for hybrid-electric conceptual aircraft design are compared. An existing 19-seat commuter aircraft is selected as the conventional baseline, and both design tools are used to size that aircraft. The aircraft is then re-sized under consideration of hybrid-electric propulsion technology. This is performed for parallel, serial, and fully-electric powertrain architectures. Finally, sensitivity studies are conducted to assess the validity of the basic assumptions and approaches regarding the design of hybrid-electric aircraft. Both methods are found to predict the maximum take-off mass (MTOM) of the reference aircraft with less than 4\% error. The MTOM and payload-range energy efficiency of various (hybrid-) electric configurations are predicted with a maximum difference of approximately 2\% and 5\%, respectively. The results of this study confirm a correct formulation and implementation of the two design methods, and the data obtained can be used by researchers to benchmark and validate their design tools.},
  language  = {en}
}
@inproceedings{ThenentDahmann2011,
  author    = {Thenent, N. E. and Dahmann, Peter},
  title     = {Increasing aircraft design flexibility - The development of a hydrostatic transmission for gliders with self-launching capability},
  series = {Deutscher Luft- und Raumfahrtkongress 2011 : Bremen, 27. bis 29. September 2011 ; Tagungsband},
  booktitle = {Deutscher Luft- und Raumfahrtkongress 2011 : Bremen, 27. bis 29. September 2011 ; Tagungsband},
  publisher = {Dt. Gesellschaft f{\"u}r Luft- und Raumfahrt},
  address   = {Bonn},
  isbn      = {978-3-9321-8274-7},
  pages     = {865 -- 883},
  year      = {2011},
  language  = {en}
}
@inproceedings{FingerGoettenBraun2018,
  author    = {Finger, Felix and G{\"o}tten, Falk and Braun, Carsten},
  title     = {Initial Sizing for a Family of Hybrid-Electric VTOL General Aviation Aircraft},
  series = {67. Deutscher Luft- und Raumfahrtkongress 2018},
  booktitle = {67. Deutscher Luft- und Raumfahrtkongress 2018},
  pages     = {14 S.},
  year      = {2018},
  language  = {en}
}
@incollection{McInnesBothmerDachwaldetal.2014,
  author    = {McInnes, Colin R. and Bothmer, Volker and Dachwald, Bernd and Geppert, Ulrich R. M. E. and Heiligers, Jeannette and Hilgers, Alan and Johnson, Les and Macdonald, Malcolm and Reinhard, Ruedeger and Seboldt, Wolfgang and Spietz, Peter},
  title     = {Gossamer roadmap technology reference study for a Sub-L1 Space Weather Mission},
  series = {Advances in solar sailing},
  booktitle = {Advances in solar sailing},
  publisher = {Springer},
  address   = {Berlin [u.a.]},
  isbn      = {978-3-642-34906-5 (Print) ; 978-3-642-34907-2 (E-Book)},
  pages     = {227 -- 242},
  year      = {2014},
  abstract  = {A technology reference study for a displaced Lagrange point space weather mission is presented. The mission builds on previous concepts, but adopts a strong micro-spacecraft philosophy to deliver a low mass platform and payload which can be accommodated on the DLR/ESA Gossamer-3 technology demonstration mission. A direct escape from Geostationary Transfer Orbit is assumed with the sail deployed after the escape burn. The use of a miniaturized, low mass platform and payload then allows the Gossamer-3 solar sail to potentially double the warning time of space weather events. The mission profile and mass budgets will be presented to achieve these ambitious goals.},
  language  = {en}
}
@article{GoettenFingerHavermannetal.2018,
  author    = {G{\"o}tten, Falk and Finger, Felix and Havermann, Marc and Braun, Carsten and Gomez, Francisco and Bill, C.},
  title     = {On the flight performance impact of landing gear drag reduction methods for unmanned air vehicles},
  series = {Deutscher Luft- und Raumfahrtkongress 2018},
  journal   = {Deutscher Luft- und Raumfahrtkongress 2018},
  publisher = {DGLR},
  address   = {Bonn},
  doi       = {10.25967/480058},
  pages     = {11 S.},
  year      = {2018},
  abstract  = {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.},
  language  = {en}
}
@article{SchildtBraunMarzocca2019,
  author    = {Schildt, Ph. and Braun, Carsten and Marzocca, P.},
  title     = {Metric evaluating potentials of condition-monitoring approaches for hybrid electric aircraft propulsion systems},
  series = {CEAS Aeronautical Journal},
  journal   = {CEAS Aeronautical Journal},
  publisher = {Springer},
  address   = {Berlin},
  issn      = {1869-5590},
  doi       = {10.1007/s13272-019-00411-3},
  pages     = {1 -- 14},
  year      = {2019},
  language  = {en}
}
@inproceedings{LudowicyRingsFingeretal.2019,
  author    = {Ludowicy, Jonas and Rings, Ren{\´e} and Finger, Felix and Braun, Carsten and Bil, Cees},
  title     = {Impact of Propulsion Technology Levels on the Sizing and Energy Consumption for Serial HybridElectric General Aviation Aircraft},
  series = {Asia Pacific International Symposium on Aerospace Technology. APISAT 2019},
  booktitle = {Asia Pacific International Symposium on Aerospace Technology. APISAT 2019},
  pages     = {14 Seiten},
  year      = {2019},
  language  = {en}
}
@article{DachwaldWurm2011,
  author    = {Dachwald, Bernd and Wurm, Patrick},
  title     = {Mission analysis and performance comparison for an Advanced Solar Photon Thruster},
  series = {Advances in Space Research},
  volume    = {48},
  journal   = {Advances in Space Research},
  number    = {11},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0273-1177},
  pages     = {1858 -- 1868},
  year      = {2011},
  language  = {en}
}
@article{ScholzLeyDachwaldetal.2010,
  author    = {Scholz, A. and Ley, Wilfried and Dachwald, Bernd and Miau, J. J. and Juang, J. C.},
  title     = {Flight results of the COMPASS-1 picosatellite mission},
  series = {Acta Astronautica. 67 (2010), H. 9-10},
  journal   = {Acta Astronautica. 67 (2010), H. 9-10},
  isbn      = {0094-5765},
  pages     = {1289 -- 1298},
  year      = {2010},
  language  = {en}
}
@inproceedings{ThenentDahmann2011,
  author    = {Thenent, N. E. and Dahmann, Peter},
  title     = {Hydrostatic propeller drive},
  series = {Proceedings of the conference : 18 - 20 May, 2011 Tampere, Finland / the Twelth Scandinavian International Conference on Fluid Power, SICFP'11. Ed.: Harri Sairiala ... Vol. 1},
  booktitle = {Proceedings of the conference : 18 - 20 May, 2011 Tampere, Finland / the Twelth Scandinavian International Conference on Fluid Power, SICFP'11. Ed.: Harri Sairiala ... Vol. 1},
  address   = {Tampere},
  isbn      = {978-952-15-2517-9},
  pages     = {217 -- 227},
  year      = {2011},
  language  = {en}
}
@inproceedings{KorschDafnisReimerdesetal.2006,
  author    = {Korsch, Helge and Dafnis, Athanasios and Reimerdes, Hans-G{\"u}nther and Braun, Carsten and Ballmann, Josef},
  title     = {Dynamic qualification of the HIRENASD elastic wing model},
  series = {Motto: Luft- und Raumfahrt: Lehre, Forschung, Industrie - gemeinsam innovativ. Deutscher Luft- und Raumfahrtkongress 2006 : Braunschweig, 06. bis 09. November 2006. Jahrbuch / Deutsche Gesellschaft f{\"u}r Luft- und Raumfahrt. 2006},
  booktitle = {Motto: Luft- und Raumfahrt: Lehre, Forschung, Industrie - gemeinsam innovativ. Deutscher Luft- und Raumfahrtkongress 2006 : Braunschweig, 06. bis 09. November 2006. Jahrbuch / Deutsche Gesellschaft f{\"u}r Luft- und Raumfahrt. 2006},
  publisher = {Dt. Gesellschaft f{\"u}r Luft- und Raumfahrt - Lilienthal-Oberth (DGLR)},
  address   = {Bonn},
  pages     = {1441 -- 1450},
  year      = {2006},
  language  = {en}
}
@inproceedings{NiedermeierClemensKowalskietal.2014,
  author    = {Niedermeier, H. and Clemens, J. and Kowalski, Julia and Macht, S. and Heinen, D. and Hoffmann, R. and Linder, Peter},
  title     = {Navigation system for a research ice probe for antarctic glaciers},
  series = {IEEE/ION Position, Location and Navigation Symposium (PLANS) ; 5-8 May 2014, Monterey, Calif.},
  booktitle = {IEEE/ION Position, Location and Navigation Symposium (PLANS) ; 5-8 May 2014, Monterey, Calif.},
  publisher = {IEEE},
  address   = {Piscataway, NJ},
  organization    = {Position, Location and Navigation Symposium <2014, Monterey, Calif.>},
  isbn      = {978-1-4799-3319-8},
  pages     = {959 -- 975},
  year      = {2014},
  language  = {en}
}
@inproceedings{SeboldtBlomeDachwaldetal.2004,
  author    = {Seboldt, Wolfgang and Blome, Hans-Joachim and Dachwald, Bernd and Richter, Lutz},
  title     = {Proposal for an integrated European space exploration strategy},
  series = {55th International Astronautical Congress of the International Astronautical Federation, the International Academy of Astronautics, and the International Institute of Space Law},
  booktitle = {55th International Astronautical Congress of the International Astronautical Federation, the International Academy of Astronautics, and the International Institute of Space Law},
  pages     = {1 -- 10},
  year      = {2004},
  abstract  = {Recently, in his vision for space exploration, US president Bush announced to extend human presence across the solar system, starting with a human return to the Moon as early as 2015 in preparation for human exploration of Mars and other destinations. In Europe, an exploration program, termed AURORA, was established by ESA in 2001 - funded on a voluntary basis by ESA member states - with a clear focus on Mars and the ultimate goal of landing humans on Mars around 2030 in international cooperation. In 2003, a Human Spaceflight Vision Group was appointed by ESA with the task to develop a vision for the role of human spaceflight during the next quarter of the century. The resulting vision focused on a European-led lunar exploration initiative as part of a multi-decade, international effort to strengthen European identity and economy. After a review of the situation in Europe concerning space exploration, the paper outlines an approach for a consistent positioning of exploration within the existing European space programs, identifies destinations, and develops corresponding scenarios for an integrated strategy, starting with robotic missions to the Moon, Mars, and near-Earth asteroids. The interests of the European planetary in-situ science community, which recently met at DLR Cologne, are considered. Potential robotic lunar missions comprise polar landings to search for frozen volatiles and a sample return. For Mars, the implementation of a modest robotic landing mission in 2009 to demonstrate the capability for landing and prepare more ambitious and complex missions is discussed. For near-Earth asteroid exploration, a low-cost in-situ technology demonstration mission could yield important results. All proposed scenarios offer excellent science and could therefore create synergies between ESA's mandatory and optional programs in the area of planetary science and exploration. The paper intents to stimulate the European discussion on space exploration and reflects the personal view of the authors.},
  language  = {en}
}
@article{MaiwaldDachwald2010,
  author    = {Maiwald, Volker and Dachwald, Bernd},
  title     = {Mission Design for a Multiple-Rendezvous Mission to Jupiter's Trojans},
  pages     = {3},
  year      = {2010},
  language  = {en}
}
@inproceedings{WellmerChenBraunetal.2007,
  author    = {Wellmer, Georg and Chen, B.-H. and Braun, Carsten and Ballmann, Josef},
  title     = {Numerical prediction of aeroelastic effects on twin-sting-rig mounted models for rear fuselage and empennage flow investigation in transonic windtunnel},
  series = {Proceedings / IFASD 2007, CEAS/AIAA/KTH International Forum on Aeroelasticity and Structural Dynamics, June 18 - 21, 2007, Stockholm, Sweden},
  booktitle = {Proceedings / IFASD 2007, CEAS/AIAA/KTH International Forum on Aeroelasticity and Structural Dynamics, June 18 - 21, 2007, Stockholm, Sweden},
  publisher = {KTH},
  address   = {Stockholm},
  organization    = {Confederation of European Aerospace Societies ; American Institute of Aeronautics and Astronautics, Reston, Va. ; Kungliga Tekniska H{\"o}gskolan, Stockholm},
  pages     = {1 CD-ROM},
  year      = {2007},
  language  = {en}
}
@article{FingerBraunBil2020,
  author    = {Finger, Felix and Braun, Carsten and Bil, Cees},
  title     = {Impact of Battery Performance on the Initial Sizing of Hybrid-Electric General Aviation Aircraft},
  series = {Journal of Aerospace Engineering},
  volume    = {33},
  journal   = {Journal of Aerospace Engineering},
  number    = {3},
  publisher = {ASCE},
  address   = {Reston, Va.},
  issn      = {1943-5525},
  doi       = {10.1061/(ASCE)AS.1943-5525.0001113},
  year      = {2020},
  abstract  = {Studies suggest that hybrid-electric aircraft have the potential to generate fewer emissions and be inherently quieter when compared to conventional aircraft. By operating combustion engines together with an electric propulsion system, synergistic benefits can be obtained. However, the performance of hybrid-electric aircraft is still constrained by a battery's energy density and discharge rate. In this paper, the influence of battery performance on the gross mass for a four-seat general aviation aircraft with a hybrid-electric propulsion system is analyzed. For this design study, a high-level approach is chosen, using an innovative initial sizing methodology to determine the minimum required aircraft mass for a specific set of requirements and constraints. Only the peak-load shaving operational strategy is analyzed. Both parallel- and serial-hybrid propulsion configurations are considered for two different missions. The specific energy of the battery pack is varied from 200 to 1,000 W⋅h/kg, while the discharge time, and thus the normalized discharge rating (C-rating), is varied between 30 min (2C discharge rate) and 2 min (30C discharge rate). With the peak-load shaving operating strategy, it is desirable for hybrid-electric aircraft to use a light, low capacity battery system to boost performance. For this case, the battery's specific power rating proved to be of much higher importance than for full electric designs, which have high capacity batteries. Discharge ratings of 20C allow a significant take-off mass reduction aircraft. The design point moves to higher wing loadings and higher levels of hybridization if batteries with advanced technology are used.},
  language  = {en}
}
@inproceedings{CarzanaDachwaldNoomen2017,
  author    = {Carzana, Livio and Dachwald, Bernd and Noomen, Ron},
  title     = {Model and trajectory optimization for an ideal laser-enhanced solar sail},
  series = {68th International Astronautical Congress},
  booktitle = {68th International Astronautical Congress},
  year      = {2017},
  abstract  = {A laser-enhanced solar sail is a solar sail that is not solely propelled by solar radiation but additionally by a laser beam that illuminates the sail. This way, the propulsive acceleration of the sail results from the combined action of the solar and the laser radiation pressure onto the sail. The potential source of the laser beam is a laser satellite that coverts solar power (in the inner solar system) or nuclear power (in the outer solar system) into laser power. Such a laser satellite (or many of them) can orbit anywhere in the solar system and its optimal orbit (or their optimal orbits) for a given mission is a subject for future research. This contribution provides the model for an ideal laser-enhanced solar sail and investigates how a laser can enhance the thrusting capability of such a sail. The term "ideal" means that the solar sail is assumed to be perfectly reflecting and that the laser beam is assumed to have a constant areal power density over the whole sail area. Since a laser beam has a limited divergence, it can provide radiation pressure at much larger solar distances and increase the radiation pressure force into the desired direction. Therefore, laser-enhanced solar sails may make missions feasible, that would otherwise have prohibitively long flight times, e.g. rendezvous missions in the outer solar system. This contribution will also analyze exemplary mission scenarios and present optimial trajectories without laying too much emphasis on the design and operations of the laser satellites. If the mission studies conclude that laser-enhanced solar sails would have advantages with respect to "traditional" solar sails, a detailed study of the laser satellites and the whole system architecture would be the second next step},
  language  = {en}
}