The lower the frictional resistance of an aircraft in the air, the lower its fuel consumption. Following nature's example, the aviation industry has long been conducting intensive research into reducing drag. In a joint project, Lufthansa Technik and BASF have achieved a breakthrough. "AeroSHARK," a surface film modeled on the fine structure of shark skin, is to be used on Lufthansa Cargo's entire freighter fleet starting in early 2022, making the aircraft even more fuel-efficient and lower in emissions.
The surface structure, which consists of ribs measuring around 50 micrometers - known as riblets - imitates the properties of sharkskin and thus optimizes aerodynamics at flow-relevant points of the aircraft. As a result, less fuel is needed overall. For use on Lufthansa Cargo's ten Boeing 777F freighters, Lufthansa Technik expects a friction reduction of more than one percent. This will enable annual savings of around 3,700 metric tons of kerosene and almost 11,700 metric tons of CO2 emissions. Extrapolated to the entire Lufthansa Cargo fleet, the annual CO2 emissions saved would be equivalent to 48 individual cargo flights from Frankfurt to Shanghai.
"Responsibility for the environment and society is a key strategic issue for us," says Christina Foerster, Member of the Executive Board of Deutsche Lufthansa AG responsible for sustainability. "We have always played a leading role in the introduction of environmentally friendly technologies. The new Sharkskin technology for aircraft shows what strong partners with great innovative strength can achieve together for the environment. This supports us in our goal of becoming climate-neutral by 2050."
"The aviation industry faces similar challenges to the chemical industry: Despite a high energy demand, continuous progress must be made in climate protection. Our close cooperation and the successful combination of our expertise in surface design and aerodynamics has now brought us a big step forward. This is an outstanding example of sustainability in action, achieved through partnership and innovative technologies," said Dr. Markus Kamieth, member of BASF's Board of Executive Directors.
"We are proud to be able to operate our entire freighter fleet even more efficiently in the future thanks to Sharkskin technology and to further reduce the carbon footprint of our modern fleet. Our investments for the introduction of 'AeroSHARK' at Lufthansa Cargo once again deliberately reaffirm our commitment to the United Nations' 'Climate Action' sustainability goal," explained Dorothea von Boxberg, Chairman of the Executive Board of Lufthansa Cargo.
In the cooperation with BASF, Lufthansa Technik is responsible for the specification of the material, the approval under aviation law, and the implementation of the aircraft modifications, which are carried out during regular maintenance layovers. With decades of expertise as an approved aviation development organization, the company will obtain a Supplemental Type Certificate (STC) for the B777F from the European Aviation Safety Agency (EASA).
"We have always used our great expertise as the world market leader for aircraft technical services also to make a contribution to reducing the ecological footprint of our industry. In doing so, we can extract significant savings potential from all aircraft generations," explains Dr. Johannes Bußmann, Chairman of the Executive Board of Lufthansa Technik AG. "I am therefore very proud that we will soon be able to transfer the positive findings of the practical test into series production with Lufthansa Cargo. The extremely constructive collaboration with BASF is also the best example of cross-industry cooperation in the service of aviation sustainability."
BASF's Coatings division develops innovative, functional films - such as Riblet surfaces - in its "Beyond Paint Solutions" unit, he said. Together with Lufthansa Technik, a solution was realized that meets the strict requirements of aviation, he said. In aviation applications, exterior surfaces are exposed to strong UV radiation as well as temperature and pressure fluctuations at high altitudes, among other things. BASF therefore focused on extreme durability and weather resistance during development. Decisive criteria for an aviation application, he said, are ease of application and handling, as well as uncomplicated reparability, for which a tailor-made concept was developed.
"As experts in surfaces, we implement customized solutions for our customers. With the innovative Sharkskin technology, we are helping Lufthansa to achieve its sustainability goals and make aviation a bit more environmentally friendly," says Dirk Bremm, head of BASF's Coatings division and in this position also responsible for functional films.
The aviation industry has long been conducting intensive research into a sharkskin for aircraft, but often only on a small scale.
At the end of 2019, Lufthansa Technik and BASF had equipped the lower half of the fuselage of a Lufthansa Boeing 747-400 for the first time with 500 square meters of such a jointly developed sharkskin surface and had this modification certified by EASA. This aircraft (registration D-ABTK) subsequently validated the savings potential of the technology in regular scheduled service on long-haul routes in more than 1,500 flight hours. This proved beyond doubt that the Sharkskin modification reduced emissions by around 0.8 percent. The savings potential for the Boeing 777F is expected to be higher, as the application here covers an even larger area, partly because of the absence of window rows on the freighter. For the validation of the savings, a software solution for consumption analyses developed by Lufthansa Technik will be used, with which the effectiveness of various aircraft modifications can be reliably proven on the basis of extensive data.
Lufthansa Technik and BASF intend to systematically develop the new technology further in the direction of additional aircraft types and even larger areas, so that in the future they will be able to provide airlines around the world with even more extensive support in achieving their emissions targets. In initial model calculations, the sharkskin technology in its maximum expansion stage could even avoid CO2 emissions on the scale of up to three percent.