Influence of surface characteristics on insect residue adhesion to aircraft leading edge surfaces

• Published in: Progress in organic coatings 2013-11, Vol.76 (11), p.1567-1575
• Main Authors: Kok, Mariana, Mertens, Tobias, Raps, Dominik, Young, Trevor M.
• Format: Article
• Language: English
• Subjects: Adhesion tests; Aircraft; Coatings; Drosophila; Insect contamination; Insects; Leading edge contamination; Leading edges; Residues; Surface roughness
• ISSN: 0300-9440; 1873-331X
• DOI: 10.1016/j.porgcoat.2013.06.013

•Coatings that could potentially mitigate insect adhesion were evaluated.•Surface roughness influenced the spreading mechanism of the insect haemolymph.•Surface roughness and energy must be optimized to ensure complete mitigation.•Area measurement of the contamination determined the effectiveness of a coating.•Polyurethane based superhydrophobic coatings showed no insect residue adhesion. Leading edge contamination caused by insects is problematic for modern aircraft utilizing laminar flow aerofoils. The residue of crushed insect bodies adhering to aircraft leading edge surfaces can cause transition of the boundary layer, from laminar to turbulent, resulting in a significant increase in drag and therefore causing an increase in fuel consumption. Consequently, current research is focused on the evaluation of novel low surface energy coatings that will reduce or prevent insect adhesion. Insect residue adhesion tests were conducted on a range of surfaces, from superhydrophobic to hydrophilic. Surface free energy of the investigated substrates was obtained from measured dynamic contact angle values and surface roughness was measured using profilometry. Live insect testing with Drosophila melanogaster and Drosophila hydei was conducted using an insect delivery device inserted into a medium-speed wind tunnel. Tests were conducted at speeds ranging from 90 to 100m/s (speeds representative of those on take-off and landing of a commercial passenger aircraft). Topography of insect residues was characterized using scanning electron microscopy and confocal laser scanning microscopy. Results obtained indicate that coatings with high surface roughness values and low wettability exhibit good anti-contamination properties.