TY  - CHAP
A1  - Ludowicy, Jonas
A1  - Rings, René
A1  - Finger, Felix
A1  - Braun, Carsten
T1  - Sizing Studies of Light Aircraft with Serial Hybrid Propulsion Systems
T2  - Luft- und Raumfahrt - Digitalisierung und Vernetzung : Deutscher Luft- und Raumfahrtkongress 2018. 4. - 6. September 2018 - Friedrichshafen
Y1  - 2018
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  - CHAP
A1  - Ludowicy, Jonas
A1  - Rings, René
A1  - Finger, Felix
A1  - Braun, Carsten
T1  - Sizing Studies of Light Aircraft with Parallel Hybrid Propulsion Systems
T2  - Deutscher Luft- und Raumfahrtkongress 2018
Y1  - 2018
U6  - http://dx.doi.org/10.25967/480227
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  - 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
T1  - Comparative Performance and Benefit Assessment of VTOL and CTOL UAVs
T2  - Deutscher Luft- und Raumfahrtkongress (DLRK) 2016, 13.-15.9.2016
Y1  - 2016
ER  - 
TY  - CHAP
A1  - Finger, Felix
A1  - Braun, Carsten
A1  - Bil, Cees
T1  - The Impact of Electric Propulsion on the Performance of VTOL UAVs
T2  - Deutscher Luft- und Raumfahrtkongress 2017, DLRK , München
Y1  - 2017
ER  - 
TY  - CHAP
A1  - Finger, Felix
A1  - Braun, Carsten
A1  - Bil, Cees
T1  - A Review of Configuration Design for Distributed Propulsion Transitioning VTOL Aircraft
T2  - Asia-Pacific International Symposium on Aerospace Technology 2017, APISAT 2017, Seoul, Korea
Y1  - 2017
ER  - 
TY  - CHAP
A1  - Finger, Felix
A1  - Braun, Carsten
A1  - Bil, Cees
T1  - An Initial Sizing Methodology for Hybrid-Electric Light Aircraft
T2  - AIAA AVIATION Forum 2018 Aviation Technology, Integration, and Operations Conference, Atlanta, Georgia, June 25 - 29, 2018
Y1  - 2018
U6  - http://dx.doi.org/10.2514/6.2018-4229
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  - 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  -