NASA, coating technology, and the lotus leaf phenomenon
NASA researchers are testing a new lotus leaf-inspired coating to repel bug residue and increase aircraft efficiency.
It only takes a brief journey during the summer months to end up with a car looking like it has driven through a plague of insects. Amplify this effect by the power of a space shuttle wingspan and splattered bugs result in a significant increase in drag.
The problem is that when an insect hits an aircraft at speed its mass ruptures and undergoes some chemical changes which make it stickier. Flying through a swarm of insects leads to an accumulation of debris on the leading edge of wings which creates drag and increases fuel consumption.
NASA researchers, in collaboration with engineers at Langley and Boeing, studied the microscopically-rough texture of lotus leaves in order to understand how the surface is so effective at repelling dirt, dust and water. Although smooth to the naked eye, the plant’s leaves are in fact covered in rough, pointy features that stop matter adhering to the surface. An evolution which helps keep the plant’s leaves clear for photosynthesis.
Inspired by the lotus leaf, researchers developed more than 200 coatings which were then tested in a wind tunnel. The top five surface coatings were then selected for flight testing by NASA and Boeing engineers in Louisiana, US – a location partly chosen due to its significant bug population.
Early indication, following 15 flights and a number of takeoffs and landings, show that the best performing coating reduced bug count by 40 per cent versus a control surface mounted next to it.
NASA’s lotus leaf project is one of many Environmentally Responsible Aviation (ERA) research projects the organisation is currently undertaking. Many cite the 75 per cent reduction of aviation emissions by 2050 as an industry target – although this is one of several targets being mooted.
Several NASA-led ERA projects are currently underway and the innovative use of materials to reduce aircraft weight and drag is central to many of these projects. We will endeavour to bring you the latest on any surface coating developments here.
The lotus leaf project is one of many biomimicry R&D projects that are looking to make exciting coating developments. Read how dolphins are inspiring aerodynamic coatings for the aerospace industry and discover more on biomimetics in our recent Blog items.
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