Fraunhofer has successfully measured Lufthansa’s aircraft wings during flight so the airline can better optimise its anti-drag coatings.
A technology inspired by sharkskin, Lufthansa’s AeroShark coating significantly reduces frictional drag and thus emissions. To attach the coating optimally, however, it is necessary to conduct flow simulations which take the actual wing shape during flight into account.
Aircraft aerodynamics can be performed on the ground to measure flow and create 3D models. However, this does not represent how wings behave during flight: aerodynamic uplift and the change in tank load can cause these parts to deflect upward by several metres.
Using models that reflect the actual aircraft shape during flight, computer-aided flow simulations of the sharkskin technology can be carried out to determine its optimum position and orientation.
Usually, at least two cameras are needed to create such a 3D model, which can be challenging to set up in a passenger aircraft. The new method developed at the Fraunhofer Institute of Optronics, System Technologies and Image Exploitation only requires one camera – the missing distance information is obtained by additional measurements on the ground.
For this purpose, the upper surface of the wing is covered with numerous measurement marks whose positions are measured with the help of a tachymeter. A single camera permanently mounted in the aircraft cabin records and locates these marks several times an hour in different flight conditions.
The positions of the measurement marks can be determined in the measurement images and converted into spatial coordinates.
On a regular flight from Zurich to San Francisco and back, the team was able to obtain the 3D model of the wing of a Boeing 777-300ER and make it available to Lufthansa Technik.
