The No Ice Rotor consortium this week reported what it claims is a breakthrough in the development, testing, and integration of a novel ice protection system (IPS) for rotor blades. The group of companies have been working as part of the European Union-backed Clean Sky 2 project to develop more environmentally-sustainable aviation technology—initially for Leonardo's Next Generation Civil Tilt Rotor (NGCTR).
This technology promises both anti-icing and deicing capabilities by incorporating embedded “heating mats” within the rotor blades. To achieve this, two heater mats were stacked on top of each other with a mechanical and electrical insulation layer between them.
“To ensure the total thickness of the heater 'sandwich' was kept as thin as possible [so as not to compromise aerodynamic performance], a special manufacturing process had to be devised and tested for the production of the demonstrator, representing a significant achievement,” said Vincent Foucart, a project officer with the EU Clean Aviation venture.
The concept was first tested for structural and environmental performance using small material test samples and full-scale rotor blade sections. During the testing phase, the system was subjected to realistic operating conditions using two demonstrators at the Rail Tec Arsenal (RTA) icing wind tunnel in Vienna, Austria.
The first demonstrator represented the root section of the rotor blade, where ice typically accumulates, and featured a primary and secondary deicing zone. Upon activation, the IPS efficiently melted the ice within minutes. A second demonstrator represented the midspan section of the rotor blade and incorporated a primary and secondary deicing and anti-icing zone.
Continuous operation of the additional anti-ice zone effectively prevented ice buildup, acting “like a parting strip between the suction side [upper] and pressure side [lower] of the airfoil [the rotor blade],” according to the Clean Aviation statement.
Over the course of 12 successful test runs, conducted under various conditions in the icing wind tunnel, the No Ice Rotor consortium collected a vast amount of data, confirming the performance of the IPS. "To take this technology to the flight test stage would require further development to ensure that the IPS system is sufficiently robust to cope with the high loads associated with tiltrotor aircraft," Foucart said.
The $1.1 million project with Leonardo was first launched in January 2017 with an original timeline of 48 months but was later extended to 73 months due to the Covid pandemic. Austrian company Villinger coordinated the No Ice Rotor consortium, receiving support from several organizations, including RTA, the Austrian Institute of Technology and its Leichtmetallkompetenzzentrum Ranshofen division, CEST Kompetenzzentrum für elektrochemische Oberflächentechnologie, and Aviatest.
The NGCTR program is a flagship Clean Sky 2 demonstrator project under the European Commission's Horizon 2020 Framework Program for Research and Innovation.