Development and Demonstration of a Low Power Electrothermal Wing Ice Protection System for Regional Aircraft

Under the EU Clean Sky 2 research project InSPIRe – Innovative Systems to Prevent Ice on Regional Aircraft, numerical and experimental studies have been performed to investigate the potential to minimise the electrical power required for wing ice protection on a regional aircraft wing. In a standard electrothermal de-ice protection scheme there is a parting strip heater which runs along the full spanwise protected extent and is permanently powered. This splits the ice formation on the leading edge into an upper and lower region, which makes it easier to shed. However, the parting strip is relatively energy intensive and contributes a significant portion of the overall power demand. Developing a system which is able to provide the desired ice protection function without a parting strip would therefore offer a substantial power saving. The great difficulty with such a system is in ensuring that acceptable ice shedding occurs. Through numerical design studies a heater layout and power scheme was developed and a system demonstrator was then manufactured and tested in an icing wind tunnel. The testing confirmed the difficulties in achieving good shedding performance without the parting strip, but a number of cases, including down to -20°C, were successful in providing reasonable ice protection performance. The main outcome of the testing was the sensitivity of shedding performance to the aircraft condition. Whereas robust de-ice scheme solutions with a parting strip can generally be developed using relatively few aircraft parameters as input (e.g. Static and Total Air Temperature), the results from testing showed that there is a much higher sensitivity to parameters such as the angle-of-attack when no parting strip is used. Overall, the results show significant potential to deliver an electrothermal ice protection scheme with power much lower than would be achievable with a standard de-icing system.