@article{GoettenHavermannBraunetal.2021,
  author    = {G{\"o}tten, Falk and Havermann, Marc and Braun, Carsten and Marino, Matthew and Bil, Cees},
  title     = {Aerodynamic Investigations of UAV Sensor Turrets - A Combined Wind-tunnel and CFD Approach},
  series = {SciTech 2021, AIAA SciTech Forum, online, WW, Jan 11-15, 2021},
  journal   = {SciTech 2021, AIAA SciTech Forum, online, WW, Jan 11-15, 2021},
  publisher = {AIAA},
  address   = {Reston, Va.},
  doi       = {10.2514/6.2021-1535},
  pages     = {1 -- 12},
  year      = {2021},
  language  = {en}
}
@article{GoettenFinger2020,
  author    = {G{\"o}tten, Falk and Finger, Felix},
  title     = {PhoenAIX - Die modulare Transportdrohne},
  series = {Ingenieurspiegel},
  volume    = {2020},
  journal   = {Ingenieurspiegel},
  number    = {1},
  publisher = {Public Verlag},
  address   = {Bingen},
  isbn      = {1868-5919},
  pages     = {38 -- 40},
  year      = {2020},
  abstract  = {Die autonome, unbemannte Luftfahrt ist einer der Schl{\"u}sselsektoren f{\"u}r die Zukunft der Luftfahrt. In diesem rasant wachsenden Bereich nehmen senkrecht startende und senkrecht landende Flugzeuge (Vertical Take-Off and Landing - VTOL) einen besonderen Platz ein. Ein VTOL-Flugzeug (manchmal auch „Transitionsflugger{\"a}t" genannt) verbindet die Eigenschaft des Helikopters, {\"u}berall starten und landen zu k{\"o}nnen, mit den Geschwindigkeits-, Reichweiten und Flugdauervorteilen des Starrfl{\"u}glers. Grunds{\"a}tzlich wird die Senkrechtstart- und -landef{\"a}higkeit sowohl von zivilen als auch von milit{\"a}rischen Betreibern unbemannter Flugger{\"a}te (UAVs) gew{\"u}nscht. Trotzdem bietet der Markt nur eine geringe Anzahl von VTOL-UAVs, da qualitativ hochwertige Entw{\"u}rfe eine ausgesprochene Herausforderung in der Entwicklung darstellen. An der FH Aachen wird deshalb seit {\"u}ber 5 Jahren an der Auslegung und Analyse von solchen unbemannten VTOL Flugzeugen geforscht. Das neuste Projekt ist der Eigenentwurf einer großen, senkrechtstartenden Transportdrohne. Das „PhoenAIX" getaufte Flugger{\"a}t wird von Falk G{\"o}tten und Felix Finger im Rahmen einer EFRE-F{\"o}rderung entwickelt.},
  language  = {de}
}
@article{FingerGoetten2019,
  author    = {Finger, Felix and G{\"o}tten, Falk},
  title     = {Neue Ans{\"a}tze f{\"u}r die Entwicklung von unbemannten Flugger{\"a}ten},
  series = {Ingenieurspiegel},
  volume    = {2019},
  journal   = {Ingenieurspiegel},
  number    = {1},
  isbn      = {1868-5919},
  pages     = {67 -- 68},
  year      = {2019},
  abstract  = {Wie sieht das unbemannte Flugzeug von {\"U}bermorgen aus? Dieser Frage stellen sich Forscher an der Fachhochschule Aachen. Die weltweit rasant fortschreitende Entwicklung des Marktes f{\"u}r unbemannte Flugger{\"a}te (UAVs - „Unmanned Aerial Vehicles") bietet großes Potenzial f{\"u}r Wachstum und Wertsch{\"o}pfung. Unbemannte fliegende Systeme k{\"o}nnen - f{\"u}r bestimmte Anwendungsgebiete - wesentlich g{\"u}nstiger, kleiner und effizienter ausgelegt werden als bemannte L{\"o}sungen. Dabei sind sich viele Unternehmen {\"u}ber das m{\"o}gliche Potential dieser Technologie noch gar nicht bewusst.},
  language  = {de}
}
@article{GoettenHavermannBraunetal.2020,
  author    = {G{\"o}tten, Falk and Havermann, Marc and Braun, Carsten and Marino, Matthew and Bil, Cees},
  title     = {Improved Form Factor for Drag Estimation of Fuselages with Various Cross Sections},
  series = {Journal of Aircraft},
  journal   = {Journal of Aircraft},
  publisher = {AIAA},
  address   = {Reston, Va.},
  issn      = {1533-3868},
  doi       = {10.2514/1.C036032},
  pages     = {1 -- 13},
  year      = {2020},
  abstract  = {The paper presents an aerodynamic investigation of 70 different streamlined bodies with fineness ratios ranging from 2 to 10. The bodies are chosen to idealize both unmanned and small manned aircraft fuselages and feature cross-sectional shapes that vary from circular to quadratic. The study focuses on friction and pressure drag in dependency of the individual body's fineness ratio and cross section. The drag forces are normalized with the respective body's wetted area to comply with an empirical drag estimation procedure. Although the friction drag coefficient then stays rather constant for all bodies, their pressure drag coefficients decrease with an increase in fineness ratio. Referring the pressure drag coefficient to the bodies' cross-sectional areas shows a distinct pressure drag minimum at a fineness ratio of about three. The pressure drag of bodies with a quadratic cross section is generally higher than for bodies of revolution. The results are used to derive an improved form factor that can be employed in a classic empirical drag estimation method. The improved formulation takes both the fineness ratio and cross-sectional shape into account. It shows superior accuracy in estimating streamlined body drag when compared with experimental data and other form factor formulations of the literature.},
  language  = {en}
}
@inproceedings{GoettenFingerBraunetal.2019,
  author    = {G{\"o}tten, Falk and Finger, Felix and Braun, Carsten and Havermann, Marc and Bil, C. and Gomez, F.},
  title     = {Empirical Correlations for Geometry Build-Up of Fixed Wing Unmanned Air Vehicles},
  series = {APISAT 2018: The Proceedings of the 2018 Asia-Pacific International Symposium on Aerospace Technology (APISAT 2018)},
  booktitle = {APISAT 2018: The Proceedings of the 2018 Asia-Pacific International Symposium on Aerospace Technology (APISAT 2018)},
  publisher = {Springer},
  address   = {Singapore},
  isbn      = {978-981-13-3305-7},
  doi       = {10.1007/978-981-13-3305-7_109},
  pages     = {1365 -- 1381},
  year      = {2019},
  abstract  = {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.},
  language  = {en}
}
@inproceedings{FingerGoettenBraunetal.2019,
  author    = {Finger, Felix and G{\"o}tten, Falk and Braun, Carsten and Bil, C.},
  title     = {On Aircraft Design Under the Consideration of Hybrid-Electric Propulsion Systems},
  series = {APISAT 2018: The Proceedings of the 2018 Asia-Pacific International Symposium on Aerospace Technology (APISAT 2018)},
  booktitle = {APISAT 2018: The Proceedings of the 2018 Asia-Pacific International Symposium on Aerospace Technology (APISAT 2018)},
  publisher = {Springer},
  address   = {Singapore},
  isbn      = {978-981-13-3305-7},
  doi       = {10.1007/978-981-13-3305-7_99},
  pages     = {1261 -- 1272},
  year      = {2019},
  abstract  = {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.},
  language  = {en}
}
@article{GoettenHavermannBraunetal.2020,
  author    = {G{\"o}tten, Falk and Havermann, Marc and Braun, Carsten and Marino, Matthew and Bil, Cees},
  title     = {Wind-tunnel and CFD investigations of UAV landing gears and turrets - Improvements in empirical drag estimation},
  series = {Aerospace Science and Technology},
  volume    = {107},
  journal   = {Aerospace Science and Technology},
  number    = {Art. 106306},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1270-9638},
  doi       = {10.1016/j.ast.2020.106306},
  year      = {2020},
  abstract  = {This paper analyzes the drag characteristics of several landing gear and turret configurations that are representative of unmanned aircraft tricycle landing gears and sensor turrets. A variety of these components were constructed via 3D-printing and analyzed in a wind-tunnel measurement campaign. Both turrets and landing gears were attached to a modular fuselage that supported both isolated components and multiple components at a time. Selected cases were numerically investigated with a Reynolds-averaged Navier-Stokes approach that showed good accuracy when compared to wind-tunnel data. The drag of main gear struts could be significantly reduced via streamlining their cross-sectional shape and keeping load carrying capabilities similar. The attachment of wheels introduced interference effects that increased strut drag moderately but significantly increased wheel drag compared to isolated cases. Very similar behavior was identified for front landing gears. The drag of an electro-optical and infrared sensor turret was found to be much higher than compared to available data of a clean hemisphere-cylinder combination. This turret drag was merely influenced by geometrical features like sensor surfaces and the rotational mechanism. The new data of this study is used to develop simple drag estimation recommendations for main and front landing gear struts and wheels as well as sensor turrets. These recommendations take geometrical considerations and interference effects into account.},
  language  = {en}
}
@inproceedings{GoettenFingerHavermannetal.2020,
  author    = {G{\"o}tten, Falk and Finger, Felix and Havermann, Marc and Braun, Carsten and Marino, Matthew and Bil, Cees},
  title     = {Full Configuration Drag Estimation of Small-to-Medium Range UAVs and its Impact on Initial Sizing Optimization},
  series = {Deutscher Luft- und Raumfahrtkongress - DLRK 2020},
  booktitle = {Deutscher Luft- und Raumfahrtkongress - DLRK 2020},
  year      = {2020},
  language  = {en}
}
@inproceedings{HippeFingerGoettenetal.2020,
  author    = {Hippe, Jonas and Finger, Felix and G{\"o}tten, Falk and Braun, Carsten},
  title     = {Propulsion System Qualification of a 25 kg VTOL-UAV: Hover Performance of Single and Coaxial Rotors and Wind-Tunnel Experiments on Cruise Propellers},
  series = {Deutscher Luft- und Raumfahrtkongress - DLRK 2020},
  booktitle = {Deutscher Luft- und Raumfahrtkongress - DLRK 2020},
  year      = {2020},
  language  = {en}
}
@inproceedings{GeibenGoettenHavermann2020,
  author    = {Geiben, Benedikt and G{\"o}tten, Falk and Havermann, Marc},
  title     = {Aerodynamic analysis of a winged sub-orbital spaceplane},
  series = {Deutscher Luft- und Raumfahrtkongress - DLRK 2020},
  booktitle = {Deutscher Luft- und Raumfahrtkongress - DLRK 2020},
  year      = {2020},
  language  = {en}
}