Design and manufacturing of an aileron for a high-aspect ratio wing with active flutter control

Abstract For future passenger aircraft, high aspect ratio wings offer significant fuel savings compared to current models. However, they also introduce a major challenge: flutter becomes a critical issue, requiring the wing to become structurally stiffer and therefore heavier. Active flutter suppression can alleviate this problem, leading to lighter structures and more flexible wings. The aim of the LuFo project WISDOM is to demonstrate an active flutter control system, combined with Maneuver Load Alleviation (MLA) and Gust Load Alleviation (GLA), by actuating the ailerons. This paper focuses on designing the aileron for structural testing, which requires addressing two key challenges: achieving a sufficient stiffness to not dampen the high actuation frequencies and introducing the loads within the small profile thickness. To meet these demands a novel structural concept has been developed for the aileron. Primarely made from Carbon-Fiber Reinforced Polymers (CFRP) Prepreg, this design features a boxed CFRP spar and load-bearing skins, minimizing the need of tooling. The structural design was calculated using finite element and analytical methods. Three ailerons were manufactured in-house at the institute of lightweight systems, utilizing a conventional autoclave process with three negative molds. During manufacturing extensive sensor systems such as Fiber-Bragg-Grating-Sensors, Fiber optical sensors, DC-based cure monitoring sensors and temperature sensors are integrated into the parts and provide valuable information about the behavior of the part and material during the curing process. While the chosen method for joining the separate composite parts is secondary bonding, the design is well-suited for alternative methods like primary bonding or Same Qualified Resin Transfer Molding (SQRTM).