@inproceedings{MayntzKeimerDahmannetal.2022,
  author    = {Mayntz, Joscha and Keimer, Jona and Dahmann, Peter and Hille, Sebastian and Stumpf, Eike and Fisher, Alex and Dorrington, Graham},
  title     = {Electrical Drive and Regeneration in General Aviation Flight with Propellers},
  series = {Deutscher Luft- und Raumfahrtkongress 2020},
  booktitle = {Deutscher Luft- und Raumfahrtkongress 2020},
  publisher = {DGLR},
  address   = {Bonn},
  doi       = {10.25967/530100},
  pages     = {8 Seiten},
  year      = {2022},
  abstract  = {Electric flight has the potential for a more sustainable and energy-saving way of aviation compared to fossil fuel aviation. The electric motor can be used as a generator inflight to regenerate energy during descent. Three different approaches to regenerating with electric propeller powertrains are proposed in this paper. The powertrain is to be set up in a wind tunnel to determine the propeller efficiency in both working modes as well as the noise emissions. Furthermore, the planned flight tests are discussed. In preparation for these tests, a yaw stability analysis is performed with the result that the aeroplane is controllable during flight and in the most critical failure case. The paper shows the potential for inflight regeneration and addresses the research gaps in the dual role of electric powertrains for propulsion and regeneration of general aviation aircraft.},
  language  = {en}
}
@misc{KeimerGirbigMayntzetal.2022,
  author    = {Keimer, Jona and Girbig, Leo and Mayntz, Joscha and Tegtmeyer, Philipp and Wendland, Frederik and Dahman, Peter and Fisher, Alex and Dorrington, Graham},
  title     = {Flight mission optimization for eco-efficiency in consideration of electric regeneration and atmospheric conditions},
  series = {AIAA AVIATION 2022 Forum},
  journal   = {AIAA AVIATION 2022 Forum},
  publisher = {AIAA},
  address   = {Reston, Va.},
  doi       = {10.2514/6.2022-4118},
  year      = {2022},
  abstract  = {The development and operation of hybrid or purely electrically powered aircraft in regional air mobility is a significant challenge for the entire aviation sector. This technology is expected to lead to substantial advances in flight performance, energy efficiency, reliability, safety, noise reduction, and exhaust emissions. Nevertheless, any consumed energy results in heat or carbon dioxide emissions and limited electric energy storage capabilities suppress commercial use. Therefore, the significant challenges to achieving eco-efficient aviation are increased aircraft efficiency, the development of new energy storage technologies, and the optimization of flight operations. Two major approaches for higher eco-efficiency are identified: The first one, is to take horizontal and vertical atmospheric motion phenomena into account. Where, in particular, atmospheric waves hold exciting potential. The second one is the use of the regeneration ability of electric aircraft. The fusion of both strategies is expected to improve efficiency. The objective is to reduce energy consumption during flight while not neglecting commercial usability and convenient flight characteristics. Therefore, an optimized control problem based on a general aviation class aircraft has to be developed and validated by flight experiments. The formulated approach enables a development of detailed knowledge of the potential and limitations of optimizing flight missions, considering the capability of regeneration and atmospheric influences to increase efficiency and range.},
  language  = {en}
}
@misc{MayntzKeimerTegtmeyeretal.2021,
  author    = {Mayntz, Joscha and Keimer, Jona and Tegtmeyer, Philipp and Dahmann, Peter and Hille, Sebastian and Stumpf, Eike and Fisher, Alex and Dorrington, Graham},
  title     = {Aerodynamic Investigation on Efficient Inflight Transition of a Propeller from Propulsion to Regeneration Mode},
  series = {AIAA SCITECH 2022 Forum},
  journal   = {AIAA SCITECH 2022 Forum},
  publisher = {AIAA},
  address   = {Reston, Va.},
  doi       = {10.2514/6.2022-0546},
  year      = {2021},
  abstract  = {This paper discusses a new way of inflight power regeneration for electric or hybrid-electric driven general aviation aircraft with one powertrain for both configurations. Three different approaches for the shift from propulsion to regeneration mode are analyzed. Numerical cal-culation and wind tunnel results are compared and show the highest regeneration potential for the "Windmill" approach, where the propeller blades are flipped, and rotation is reversed. A combination of all regeneration approaches for a realistic flight mission is discussed.},
  language  = {en}
}