DLR, the German aerospace centre, has announced the first flight of the experimental HY4, billed as the world’s first four-seat passenger aircraft powered solely by a hydrogen fuel cell system. The 15-minute test flight took place at Stuttgart Airport on 29th September.
The HY4 was developed by the DLR Institute of Engineering Thermodynamics together with partners Hydrogenics, Pipistrel, H2FLY, the University of ULM and Stuttgart Airport. DLR researchers were responsible for developing the hydrogen fuel cell power train and installing it in the aircraft. The twin-fuselage airframe is based on Pipistrel’s Taurus G4 electric aircraft, a technology demonstrator originally built for the NASA Google Green Flight Challenge 2011.
The power train consists of a hydrogen storage system, a low-temperature hydrogen fuel cell and a battery. The fuel cell converts hydrogen directly into electrical energy. The only waste product from this process is water. An electric motor uses the power thus generated to propel the aircraft.
A high-performance lithium battery covers peak power loads during take-off and when climbing. If the hydrogen required for the fuel cell is generated via electrolysis using power from renewable energy sources, the HY4 can fly without generating any emissions at all. The aircraft is operated by the DLR spin-off H2FLY.
André Thess, Head of the DLR Institute of Engineering Thermodynamics explains that the goal is to further improve the fuel cell power train and, in the long term, use it on regional aircraft with up to 19 passengers. DLR is currently involved in electric aviation together with industry partners Airbus Group and Siemens, as well as 20 university institutes and Helmholtz centres as part of the Helmholtz Association's DLR@Uni Electric Flight initiative.
The HY4 has a motor output of 80kW, a maximum speed of approximately 200km/h and a cruising speed of 145km/h. Depending on speed, altitude and load, it can achieve a range of between 750 and 1,500km. The maximum weight of the aircraft is 1,500kg.