The evolution of Riblet technology

Sir James Gray, who was a British zoologist focusing on animal motion, claimed, that dolphin skin must have special drag reducing properties due to the seeming mismatch of a dolphin‘s physical power and its swimming speed. This so-called Gray‘s paradox was disproved in 2008.

Based on Gray's Paradox, the German aviation engineer Max Kramer created the hypothesis, that the dolphin's skin interacts with the water by stabilizing the flow and delaying the transition to turbulence.

First fundamental studies on Riblets were conducted in the 1970s by the NASA Langley Research Center. The respective paper was published in 1978 by Walsh and Weinstein.

Another study of Walsh at the NASA Langley Research Center, published in 1986, showed the immense potential for drag reductions and according economic savings by Riblets in aviation.

3M suggested, that Riblets should be molded on lightweight plastic film.

In 1987, the racing yacht 'Stars and Stripes 87’, equipped with Riblets from NASA and 3M, won the America's Cup.

Results of first experiments of Riblets on a Boeing airplane were published in 1987 by McLean et al. .

Airbus conducted experiments with Riblet film applied to an A320.

The effects of Riblets on flat plates and on boat hulls were investigated in wind tunnels and towing tunnels by Choi et. al. .

Szodruch estimated a drag reduction of 2% for an Airbus A320 by covering 70% of its surface with Riblets.

Koury & Virk conducted experiments on pipe flows and tested 3M foil in pipes.

In 1995 Goldstein et al. developed a numerical model to analyze a turbulent flow over a surface with Riblet structures.

Multiple experiments and flight tests on reducing aerodynamic drag with Riblets were led by the German aerospace engineer D. W. Bechert.

Bechert and his team won several international science awards for their work on Riblet surfaces.

Bechert et al. experimentally investigated a three-dimensional Riblet structure with interlocking surface elements like on actual sharkskin.

In 2002, Brennan developed sharkskin inspired surfaces to prevent fouling of submarine and ship surfaces together with the US Office of Naval Research.

The Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM) investigated painted Riblets and holds a patent for the respective application technology.

IFAM tested the painted Riblets in terms of stability on an airplane in operation.

bionic surface technologies GmbH completed their first aerodynamic flight tests with a Zivko Edge 450 V2, which was fully covered with Riblets.

The effects of Riblets on flat plates and on boat hulls were investigated in wind tunnels and towing tunnels by Choi et. al. .

The 33. America's Cup in 2010 was won by the BMW Oracle Team, whose racing yacht was covered with 3M Riblet foil.

In the same year bionic surface technologies GmbH performed their first full scale wind tunnel test with a GT race car.

bionic surface technologies GmbH successfully realized Riblet applications in the DTM (Deutsche Tourenwagen-Masters), which brought significant performance advantages. Unfortunately, Riblets were banned from the DTM by regulations 3 years later in 2013.

Sareen investigated different Riblet sizes with a sawtooth geometry on a DU-96-W-180 wind turbine airfoil.

bionic surface technologies GmbH conducted their first Riblet tests on a Formula 1 car.

IFAM and the Hamburg Ship Model Basin (HSVA) tested painted Riblets on ship surfaces. They indicated a possible drag reduction of 3,5% - 5%.

The Swiss Air Race Team won the Reno Air Race in 2013. Their racing aircraft “Scarlet Screamer” was covered with Riblets designed and applied by bionic surface technologies GmbH.

IFAM and Lufthansa Technik performed their first durability tests of painted Riblets on a civil aircraft in service.

Peugeout presented their concept car 'Peugeot Exalt' at the Peking motor show. The rear wing was covered with Riblet structures.

Riblets, designed by bionic surface technologies GmbH, were used in bobsleigh races at the Olympic Winter Games 2014 in Sochi.

bionic surface technologies GmBH simulated Riblets on a Boeing 747-400 in cooperation with Lufthansa. Potential fuel savings were estimated at around 3%.

Riblets were applied to aircraft at the Red Bull Air Race for the first time. The design and realization was performed by bionic surface technologies GmbH.

Eschmann Textures developed a scratch-resistant surface, inspired by sharkskin.

Painted Riblets were tested on wind turbines in service by IFAM and bionic surface technologies GmbH. A significant performance increase was indicated.

The EU-funded research project ReSiSTant (“Large Riblet Surfaces with Super Hardness, Mechanical and Temperature Resistance by Nano Functionalization”) was started by bionic surface technologies GmbH, General Electric, MAN, Lufthansa and others.

bionic surface technologies GmbH applied Riblets on the Vattenfall Solar Team’s (today Brunel Solar Team) solar car “NunaX”.

The Red Bull Air Race was discontinued in 2019. Until then, 49% of all podium positions and 51% of all victories were flown with Riblets.

NIKON Corporation and bionic surface technologies GmbH announced a Joint Development Agreement, focusing on the development of laser manufactured Riblet surfaces.

The athlete Dario Costa performed the world record breaking “Red Bull Tunnel Pass”. Equipped with Riblets on his Zivko Edge 540 V2, he flew through 2 highway tunnels with a total length of 2,26 km.

BASF and Lufthansa Technik receive the permit for applying their AeroSHARK foil on the passenger airplanes Boeing 777-300ER & Boeing 777F.

SWISS became the first airline to use Riblet foil on a passenger airplane in regular operations with the BASF AeroSHARK technology. It saves over 1% in fuel consumption, meaning a yearly CO2 reduction of over 1200 tons per plane.

A Boeing B777-F from Lufthansa Cargo started its route service as the first cargo plane equipped with Riblet foil.