Lilium has completed the first phase of integration testing for the electric propulsion system that will power its eVTOL aircraft. On August 21, the German company said the results achieved at its electrical power system laboratory near Munich represent a significant milestone in its efforts to secure flight conditions approval and type certification for its four- to six-passenger Lilium Jet.
The equipment assembled in the laboratory replicates the eVTOL aircraft’s powertrain, which will consist of 30 tilting ducted fan electric engines installed in the wing and canard. The ground test rig allows Lilium’s engineers to assess its performance in a controlled environment. Meanwhile, elsewhere in the company’s headquarters, work continues to build the first two full-scale prototypes.
The laboratory is also equipped to integrate low-voltage systems that support the aircraft’s avionics and cabin systems. It also has onboard energy isolation units that prevent hazardous energy release and a battery charging station.
Test Data Goes to EASA
Using Lilium’s own software, engineers plot flight profiles and gather real-time data from the propulsion system test runs. This data is collated to provide evidence for EASA, which is handling the initial type certification process the manufacturer aims to complete by the end of 2025. The company recently announced it will not start test flights with its prototype until early 2025, having previously targeted this to begin by the end of 2024.
Lilium developed the laboratory with Italian partner EN4, with software support having come from NI. The facility allows engineers to inject faults into the propulsion system to check whether it is sufficiently robust to deal with equipment failures.
Honeywell and Japan's Denso are key partners in developing the electric propulsion system for Lilium, with SKF and Aerononamic also contributing expertise. Lilium started assembling the powertrain in September 2023.
Since 2022, Lilium has conducted flight tests with a pair of its Phoenix full-scale technology demonstrator aircraft. During exercise conducted in Spain, it has achieved transitions from vertical to horizontal flight and cruise speeds of up to 136 knots.