eRay, Polaris, AirBox One: Innovative Concepts for the Aircraft of the Future

Two aviation research institutes, one competition: The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) and the National Aeronautics and Space Administration (NASA) in the United States set students from both countries a Design Challenge. They were asked to come up with fresh, eco-friendly ideas for the aviation of tomorrow and the aircraft of the future. The sky was the limit in terms of creativity, but the designs submitted did have to use alternative fuels, be energy-efficient and quiet. After the award ceremony in Braunschweig in August 2018, the winning team travelled to NASA in the USA to exchange ideas. InnoFRAtor presents the winners of the Design Challenge and their innovative projects.

First Prize – The eRay Aircraft Concept

With their concept, the winning team from Technical University of Munich – Alexander Frühbeis, Isa Held, Patrick Sieb and Artur Usbek – focused on improving aerodynamics and reducing weight compared to the reference aircraft, Airbus A321. The turbo-electric propulsion units on the trailing edge of the wings allow the eRay Aircraft Concept to exploit airflows more effectively. The units absorb the boundary layer – which actually raises aerodynamic drag – directly from the wings, thus increasing the engines’ efficiency. In addition, the eRay’s smaller tail surfaces reduce air resistance. For the fuselage, the Munich-based team’s design uses more structural components made of carbon-reinforced plastics, and replaces windows in the cabin with projections to reduce fuselage mass. Near airports, the eRay is powered by batteries to minimize noise emission. This also contributes significantly to the eRay Aircraft Concept’s 64 percent reduction in energy consumption.

Second Prize – Polaris Aircraft Design Concept

A design featuring a novel turbo-electric propulsion architecture that uses liquid hydrogen for fuel was the key to success for the team awarded second prize – Tobias Dietl, Jonas Karger, Katrin Kaupe, Andreas Pfemeter, Philipp Weber and Alexander Zakrzewski from the University of Stuttgart. Unlike the reference aircraft, the A320, the Polaris does not have a vertical stabilizer on the fuselage. Instead, the horizontal stabilizers situated on the tail curve upwards. Located between these and the fuselage, contra-rotating propellers on each side increase the propulsion efficiency. Split winglets also contribute to the reduction in fuel consumption. The liquid hydrogen that fuels the aircraft is contained in hydrogen tanks in the storage space under the passenger cabin. For long haul flights, the Polaris can be fitted with optional additional tanks.

Third Prize – AirBox One

For short and medium-haul aircraft, take-off and ascent account for a relatively large part of the total flight. In these phases, fuel consumption is at its highest. With this in mind, the third prize winners – Hendrik Fuest, Joel Rösick, Marc-Antoine Le Gars, Philipp Podzus and Thomas Lürkens from RWTH Aachen University – developed an external booster module, the AirBox Booster, for their aircraft design, AirBox One. The AirBox Booster, an autonomous aircraft, detaches itself from the plane after the ascent phase and returns automatically to the airport. A further weight-reducing feature of the AirBox One is that it does not carry its own landing gear, but lands on a three-wheeled base at the airport. This battery-operated system brings the aircraft into its parking position and supplies it with power. The AirBox One owes its name to the wings, which extend like a box from the front of the aircraft along its sides, and then over the fuselage to the rear.

Text by Marion Frahm
Illustrations: Technical University of Munich (2), University of Stuttgart, RWTH Aachen University