E. Benini, M. Bertolini, L. Dal Toso, M. Kerr, M.S. Faraoni, A. Dal Monte, G. Misté, R. Ponza
Università di Padova,
Keywords: windscreen, hydrophobicity, solgel coating
Summary:Aircraft canopies and windshields must keep pilots’ visibility at excellent levels under several operating conditions, particularly under heavy rain occurring during flight. To this purpose, the majority of modern commercial aircrafts use wipers to shed water from the windshields. Use of wipers is no longer foreseen in some future civil aircrafts such as the Next Generation Civil Tilt Rotor (NGCTR) while, for example, fighter jets do not possess windshield wipers since a long time due to their operational requirements of high speeds and for the low observable (stealth) constraints of modern aircrafts. A durable, surface coating on the windshield to shed water would be an ideal solution to maintain visibility without using wipers and will be of fundamental importance to limit the formation of rain-induced ice on windscreen. Today’s commercially available rain repellent treatments have poor durability and weather resistance, and they cannot be applied to polymeric transparent substrates, such as aircraft canopies/windshields. In fact, liquid treatments rubbed onto the surface of the windshield must be applied periodically or as needed as their performance degrades rapidly over time. The HaSU project, funded by the European Commission under the ClanSky2 platform - currently at its final stages - is about the design and development of a rain repellent substrate capable of forming highly durable hydrophobic coatings for windshields based on a particulate inorganic homogenously distributed throughout a polymeric matrix. The present paper describes the results achieved so far in the HaSU project. In particular, results dealing with experimental testing and qualification on hydrophobic specimens according to RTCA DO-160 (Environmental Conditions and Test Procedures for Airborne Equipment) are presented: evidences from tests on hydrophobicity, taber abrasion, UV stability, transparency, abrasion resistance, ice-adhesion and solvent resistance will be shown and discussed.