Two giants of German engineering have joined forces to market their revolutionary drag-reducing LEAF technology. The laser-guided treatment adds shark skin ‘riblets’ to the top surface of aircraft paint. It is expected to save the aviation industry $150b of avgas annually.
German laser specialist 4JET and aircraft paint whiz Mankiewicz are in the final throws of the development of next-generation shark skin paint. The companies’ Laser Enhanced Air Flow technology (LEAF) involves the use of lasers to create patterns of grooves (‘riblets’) in the top layer of aircraft paint.
The presence of the riblets is known to reduce aircraft drag by 10%; the ensuing drag reduction leads to fuel savings of around 1%. That equates to worldwide commercial airliner savings of around $150 billion per year, according to JoltCapital.
The two companies will this year announce their intention to market the technology commercially.
What is the shark skin effect?
The LEAF system etches billions of tiny channels into the surface of aircraft paint. These riblets reduce the air-flow resistance of a fast-moving object.
The process mimics the surface contours of a shark’s skin, which is covered in millions of rows of small, tooth-like structures. These scaly knurls are often only a fifth of a centimetre in length but their presence reduces drag.
As a consequence of this evolutionary glitch the shark is able to pass through water relatively unhindered.
The Mako shark – which is thought to possess these scales in abundance – can swim through water at speeds of up to 60mph. It is believed the species could reach a top speed of around 80mph.
Natural features that lend sharks their exceptional manoeuvrability and speed have for a long time influenced our development of friction-reducing materials.
According to Maggie Hiufu Wong writing for CNN, German carrier Lufthansa undertook a study of shark skin paint technology in 2013. Its research was buoyed by Airbus and the Fraunhofer Institute for Manufacturing Technology and Advanced Materials.
The programme saw the testing of new shark skin surface coatings on the wings of two A340-300s. The coating significantly reduced drag, and was observed to be ‘dirt-repellent, UV-stable and abrasion- and erosion-resistant,’ writes Wong.
Old-style vs. new-style
However, laser systems intended to create shark skin have up until now proved slow and impractical. Early techniques could not agitate a paint surface quickly or accurately enough to make the paint process financially viable.
4JET’s innovative design creates laser interference patterning at 500 times the rate of anything that has come before, reports David Belforte of Industrial Laser Solutions. The LEAF technology etches numerous riblets within a single linear operation, which leads to greater productivity.
According to Belforte, the greater precision affected by LEAF enables, ‘the creation of 15 kilometers of riblets—equal to about 1 m2 of riblet surface—within less than one minute.’
Tiny adjustments to riblet geometries are also possible. LEAF lasers easily navigate variable targets such as curved and riveted surfaces. Furthermore, the process renders little need for a post-process clean-up, and can be operated by robots.
Partnership for the future
Commercial availability of the ground-breaking shark skin paint system is eagerly anticipated.
It is predicated 4JET and Mankiewicz will make an official joint announcement at the IntAirCoat Conference on the 14th and 15th May in Hamburg, Germany.
According to JoltCapital, Andreas Ossenkopf, Director Head of Aviation at Mankiewicz said, ‘We are looking forward to actively writing another chapter in the history of aviation coatings and shaping the future of sustainable aircraft.’
With 4JET we are glad to have such a competent partner of the laser industry at our side and look forward to the future cooperation and commercialization of this ground breaking new method to save fuel and thus contribute to a greener future.’
In March of this year the USAF revealed its latest foray into the use of shark skin technology. Alex Matthews-King for The Independent writes that Boeing and the US Army are part-funding research into drag-resistant paints.