A European consortium is testing shape-changing landing flaps as part of a project designed to reduce aircraft kerosene consumption.
Inspired by the ability of birds to spread their feathers to control the aerodynamic properties of their body, the flaps, developed in the framework of the EU-funded SARISTU project, rely on stretchable skin that attaches the flap to the wing instead of a conventional axis.
“We’ve come up with a silicon skin with alternate rigid and soft zones,” said Andreas Lühring from the Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM). “There are five hard and three soft zones, enclosed within a silicon skin cover extending over the top.”
The mechanism altering the shape of the landing flap itself sits underneath the soft zones covering the most stressed parts of the wings. The system uses smart algorithms calculating the best shape with regards to the required aerodynamic behaviour.
Four 90 centimetre-long prototypes made of flexible elastomeric foam are currently undergoing testing in a wind tunnel. The material used is extremely resilient and capable of withstanding temperatures between minus 55 and 80 degrees Celsius, making it suitable for aerospace applications.
More than 60 European research and industry organisations take part in the SARISTU project (short for Smart and Intelligent Aircraft Structures), aiming to address the environmental issues surrounding the growing aircraft transportation.
The project, expected to be completed next year, wants to find ways to reduce kerosene consumption of commercial aircraft by six per cent. The flexible landing flaps are only one of the many innovations explored. The Fraunhofer researchers have previously developed flexible wingtips that allow keeping air resistance at the minimum.
Airport congestion has reached staggering levels as some 2.2 billion people a year take to the skies for business or pleasure. As their numbers grow and more jets add to pollution in the atmosphere, the drawbacks to the popularity of flying become obvious. This has encouraged airlines, aircraft manufacturers and researchers to pull together to reduce airliners’ kerosene consumption and contribute to protecting the environment.