The surface structuring of metallic sheets or foils to create riblets – which reduce the skin friction drag of an aircraft – has been developed by EADS as an alternative to the currently-available polymeric foils.
The metallic riblet foils developed at EADS show higher mechanical stability than the commercially available polymeric foils. They are manufactured either by rolling, embossing or spraying of metallic nano-powders.
Shaped surfaces that are inspired by the ridged scales of sharks have been applied on aircraft to reduce skin friction and drag, thereby lowering fuel consumption and CO2 emissions. Compared to existing polymeric riblet foils and paints, the EADS-developed metallic foils offer a significantly improved stability against mechanical impacts such as erosion by sand and rain. The metallic riblet structures can
either be manufactured by state-of-the-art technologies like rolling or embossing, or by spraying metallic nano-powders on an already-structured mold or roller. The metallic foils are functionalized to ensure a durable bonding to the substrate (metallic or fiber reinforced composite) and also are functionalized on the top to protect the micro-structures from contamination.
Reduction of skin friction drag of civil and military aircraft, rotor blades, as well as for ships (using other riblet structure dimensions).
Reduction of fuel consumption and CO2 emission by reduction of the skin friction drag. Improved durability against mechanical impacts when compared to polymeric foils and paints. Potential contribution to lightning strike protection.