The German research project, funded by the Federal Ministry of Education and Research (BMBF) under grant 20Y1702F, ran from 1 January 2018 to 31 December 2022 and was coordinated by Prof. Dr.-Ing. Michael Sinapius of the Institute for Mechanics and Adaptronics at the Technical University of Braunschweig. Its goal was to develop an electro‑mechanical anti‑icing system for helicopters that uses piezoelectric energy converters instead of conventional thermal heaters. The system is designed to be non‑rotating, eliminating moving parts and reducing energy consumption, which is critical for small and medium‑size helicopters that cannot afford the high power demands of existing thermal de‑icing solutions.

The technical work focused on the design, construction, and testing of a piezoelectric actuator array mounted on a horizontal stabilizer of an EC 145 helicopter supplied by Airbus Helicopters. The stabilizer was shortened to 1200 mm to fit the test rig at the TU Braunschweig wind tunnel, which has a 450 mm wide test section. Actuators were positioned outside the icing zone to avoid thermal interference, and the system was driven at specific frequencies determined by modal analysis. A finite‑element model in Ansys 18.2 was validated by experimental modal testing of the real stabilizer. The piezoelectric array was capable of generating vibrations up to 30 m/s wind speeds, matching the most severe icing conditions encountered in flight.

Ice removal experiments were carried out in a climate wind tunnel at –5 °C with clear ice layers of varying thickness. The results, summarized in a table in the report, show that the system effectively removes ice when the layer thickness is between 3 mm and 6 mm. For layers thinner than 3 mm or thicker than 7 mm, no measurable de‑icing effect was observed. The successful removal was associated with specific resonant frequencies: 260 Hz for 4 mm ice, 900 Hz for 5 mm, and 1.5 kHz for 6 mm. The experiments also revealed local ice shedding, cracking, and delamination, confirming that the piezoelectric vibrations can disrupt ice adhesion without heating the surface. Mixed and rough ice tests at –10 °C did not yield significant de‑icing, indicating that the system’s effectiveness is limited to clear ice under the tested conditions.

The project also produced a demonstrator component and integrated the piezoelectric system into a full‑scale test rig. The demonstrator was evaluated in collaboration with the German Aerospace Center (DLR) using a centrifuge test stand, and the results were documented in the final report. Minor delays in the work packages 4.1.3, 4.5.3, and 4.6.3 were absorbed by a cost‑neutral extension of the overall project, ensuring that all planned milestones were met.

Collaboration within the consortium was tightly coordinated. Airbus Helicopters supplied the stabilizer and provided aerodynamic data; DLR contributed the centrifuge test facility and expertise in high‑speed testing; and the TU Braunschweig team handled design, simulation, and on‑site testing. No external partners outside the consortium were involved. The project’s outcomes demonstrate a viable, energy‑efficient alternative to thermal de‑icing for helicopters, with clear performance metrics for clear ice removal in the 3–6 mm thickness range at –5 °C.