Preliminary aircraft design for a midrange reference aircraft taking advanced technologies into account as part of the AVACON project for an entry into service in 2028 / S. Woehler and J. Hartmann (German Aerospace Center (DLR), Hamburg, Germany), E. Prenzel and H. Kwik (Airbus S.A.S., Hamburg, Germany) ; Deutscher Luft- und Raumfahrtkongress 2018