Fraunhofer Institute for High-Speed Dynamics, Ernst-Mach-Institut, EMIRain and hail damage aircraft wings—with noticeable consequences for aerodynamics and fuel consumption. New materials promise a solution.
April, 2026. To reduce the environmental footprint of short- and medium-haul aircraft, the design of the wings can be optimized. The “Ultra Performance Wing” (UP Wing) project, in which Fraunhofer EMI is also involved, is making a significant contribution to this effort. The goal is to reduce fuel consumption by 30 percent.
Fraunhofer EMI is collaborating with the lead partner, Fraunhofer IFAM, on two subprojects that investigate the resistance of new coatings to rain and sand erosion as well as the robustness of an innovative wing structure against hail impact.
In this context, Fraunhofer EMI contributes its expertise in the simulation of impact processes and in highly dynamic experiments.
Repeated high-speed droplet impacts increase the surface roughness of wing leading edges by forming small craters—and thus increase drag. To investigate this effect,our scientists developed a method that, for the first time, simulates the repeated impact of hundreds of raindrops on the same spot in three dimensions.
The simulations were performed using the EMI software "APOLLO Blast Simulator," coupled with the EMI structural solver "SOPHIA." Soft aluminum, which is frequently used in aircraft construction as a corrosionprotective coating, served as the test material.
The results reveal new details about crater formation: as the crater depth increases, the pressure at the crater center rises. The reason is the increasing acceleration of the water towards the deepest point in the center of the crater. Currently, Fraunhofer EMI is currently investigating how the pressure loading on the undamaged surface changes when coatings developed by project partners are applied.
In the second subproject, Fraunhofer EMI is analyzing hail impact on fiber-reinforced plastic panels. This material is intended for use in adaptively variable wing leading edges that optimize airflow. Following impact testing with ice spheres, ultrasonic inspections determined the impact velocities at which delamination occurs in the fiber layers. The results are incorporated into a material model that will enable realistic simulations of hail damage in the future.
UP Wing is part of the “Clean Aviation” research program funded by the European Union. The three-year research project brings together an interdisciplinary consortium of industry, research institutes, and universities.
