Imitating nature: Sharkskin for airplanes

The lower a plane’s frictional resistance in the air, the lower its consumption of fuel. That’s why the aviation industry has been researching how aircraft surfaces can be given an aerodynamically optimized design for several years now.

Imitating nature: Sharkskin for airplanes

The lower a plane’s frictional resistance in the air, the lower its consumption of fuel. That’s why the aviation industry has been researching how aircraft surfaces can be given an aerodynamically optimized design for several years now.
Therefore, it has taken its inspiration from nature: for example, from sharkskin, which has a particularly low flow resistance. The project “FAMOS” – which was just recently successfully wrapped up by Lufthansa Technik, aircraft manufacturer Airbus and bwm (Bremer Werk für Montagesysteme) in Hamburg – has made great progress in this area. During the project, a robot system was developed that applies sharkskin-like structures – what are called “riblets” – over a large surface on planes.

FAMOS stands for “Guidance System for Automated Application of Multifunctional Surface Structures” in German. Despite its cumbersome name, it does offer airlines a number of crucial advantages: “Our research has shown that the riblets make it possible for us to reduce airflow resistance by five to eight percent, thus allowing airline operators to save around one and a half percent in fuel,” says project manager Dr. Mathias Nolte from Lufthansa Technik. This results in a reduction of operating costs and environmental pollution. For the Lufthansa fleet alone, this innovation may result in a savings of about six million liters of kerosene per year and thereby reduce CO2 emissions to 200,000 tons.

The “FAMOS” robot cleans, removes paint and applies coats fully automatically.

The project funded by the German Federal Ministry of Economics and Energy builds upon previous research, in which new paints were developed and the fuel-saving coating was able to successfully endure over the long run under real flight-operation conditions. Previously, no solution existed as to how sharkskin can be cost-efficiently applied to large surfaces such as wings at a high level of quality in an industrial process. Success, however, has now been achieved. Similar to a stamp, the newly developed robot arm embosses the sharkskin onto the surface with a freshly applied special coating. The coating is then cured to harden with UV light and forms an aerodynamically optimized structure measuring 0.1 mm in height. The robotic system also takes over the previous cleaning of the aircraft surface and removes old layers of paint.

ALL AIRCRAFT TYPES CAN BE COATED WITH SHARKSKIN STRUCTURES

The coating can be used on all types of aircraft, however, “FAMOS” has set its focus on long-haul aircraft, such as the Airbus A330, A340 and A350. For the time being, the sharkskin has been applied to the upper side of the wings as well as to the upper and lower sides of the tailplane. Until the new coating technology from Airbus can be used in aircraft production or by Lufthansa Technik during maintenance, further application areas, especially on the fuselage, are to be tested.
Text by Gesine Oltmanns
Photos: ZAL/Michael Lindner
The project funded by the German Federal Ministry of Economics and Energy builds upon previous research, in which new paints were developed and the fuel-saving coating was able to successfully endure over the long run under real flight-operation conditions. Previously, no solution existed as to how sharkskin can be cost-efficiently applied to large surfaces such as wings at a high level of quality in an industrial process. Success, however, has now been achieved. Similar to a stamp, the newly developed robot arm embosses the sharkskin onto the surface with a freshly applied special coating. The coating is then cured to harden with UV light and forms an aerodynamically optimized structure measuring 0.1 mm in height. The robotic system also takes over the previous cleaning of the aircraft surface and removes old layers of paint.

All aircraft types can be coated with sharkskin structures

The coating can be used on all types of aircraft, however, “FAMOS” has set its focus on long-haul aircraft, such as the Airbus A330, A340 and A350. For the time being, the sharkskin has been applied to the upper side of the wings as well as to the upper and lower sides of the tailplane. Until the new coating technology from Airbus can be used in aircraft production or by Lufthansa Technik during maintenance, further application areas, especially on the fuselage, are to be tested.
The “FAMOS” robot cleans, removes paint and applies coats fully automatically.
Text by Gesine Oltmanns
Photos: ZAL/Michael Lindner