- Over the next four years, DLR (German Aerospace Center) wants to develop a concept that brings together visions for sustainable air transport.
- The focus is on propulsion system concepts for short-haul aircraft that enable significantly reduced emissions and less noise. Use of batteries, fuel cells and hydrogen is examined.
- Investigated will be the impact on the environment and the entire air transport system.
How can airborne electric mobility be achieved while greatly reducing the emissions due to air transport? How can aircraft with alternative propulsion systems be constructed – both environmentally friendly and economically viable? Will such an aircraft lead to changes to other parts of the air transport system, such as airports or maintenance facilities? The German Aerospace Center intends to answer these questions over the next four years.
Since the beginning of 2020, 45 researchers from 20 different DLR institutes have been working together on the “Exploration of Electric Aircraft Concepts and Technologies” (EXACT) project. The project’s goal is to develop new technological components for an environmentally friendly commercial aircraft.
The overall objective is to make advances in the technologies necessary to build a passenger aircraft with at least 70 seats and a range of 2000 kilometres (1080 nautical miles).
Different hybrid-electric propulsion concepts and possible aircraft configurations are being investigated during the initial stage. However, the researchers will also look at airport infrastructure and the likely effect of new propulsion systems on our atmosphere and climate.
Project leader is the DLR Institute of System Architectures in Aeronautics.↗︎
“DLR has a globally unique competence for conducting such complex studies. Our 45-person team is combining expertise from their various fields of research. This will enable us to achieve both the thematic breadth and the scientific depth that this subject merits.”
Johannes Hartmann, DLR Institute of System Architectures in Aeronautics
Digital design process
The researchers draw upon data from an aircraft’s entire life cycle. All the way from design to production, operation and subsequent decommissioning. The specified objectives are that the aircraft’s emissions should not have a negative effect on the climate, and that its operation should be economically viable.
The design process takes a whole-system view and is aligned with these goals. The planning of production, operation and maintenance are an integral part of the design from the very start.
In the past, aircraft design was primarily driven by cost considerations, with climate impact only being analysed later on. Hartmann says that for the first time they would now reverse this process. The researchers have to adopt a revolutionary approach to their work.
Climate-neutral propulsion systems
Aircraft with an improved carbon footprint require fundamentally new propulsion technologies. The project team is investigating which propulsion concepts for short-haul aircraft would result in significantly reduced emissions and less noise during operation. At the same time, these concepts have to remain compatible with the business interests of the operators. Batteries, fuel cells and hydrogen offer the potential to meet these requirements.
For several years already, the DLR Institute of Engineering Thermodynamics↗︎︎ has been analysing and evaluating the performance of different types of fuel cells for use in air transport. Fuel cells are put together in the laboratory and tested using the Hy4↗︎ passenger aircraft. The knowledge gained in the EXACT project, coupled with simulation models and pilot applications, will now be harnessed to assess how hybrid energy concepts can interact and be used in high performance aircraft.
Air transport system 2040
New types of aircraft will have an impact on the entire air transport system. Kai Wicke of the DLR Institute of Maintenance, Repair and Overhaul↗︎ is looking at the operational and environmental integration of new aircraft configurations as part of the EXACT project. He explains that the researchers take a “whole-system approach” to fully examine the impact on the ecosystem and the air transport system by a new hydrogen, fuel cell or battery powered aircraft.
The team is developing models for climate impact, noise, product and energy lifecycles. Alongside the effects on the environment, the researchers will also examine the required investment and the costs of operation and maintenance. Special refuelling systems would be required if aircraft are to be powered with hydrogen. Batteries will need to be charged, stored and recycled.
Photo Credit: DLR (CC-BY-3.0)