Ground resonance test and aeroelastic model validation of an innovative regional aircraft fitted with innovative wing tip (IWT) and adaptive morphing winglet (AMW)

These last years, many economic and financial efforts have been made by the European Commission in order to encourage more and more the manufacturing of Innovative Regional Aircraft all over the world. Leonardo is leading several research project launched in the CLEAN SKY 2 (CS2) field. The major challenges here presented are the design and the related aeroelastic qualification of newer systems aimed at in-flight load control & alleviation, such as the innovative wingtips (IWT) and the adaptive morphing winglets (AMW) that have been tested on-ground and the IWT also in-flight, installed on the CS2 FTB#1 (Flight Test Bed) demonstrator, used to achieve the TRL6. The first flight in configuration FTB#1+IWT has been performed in 12/02/2024. On the roadmaps that bring to the permit to fly, aeroelastic clearances must be provided by theoretical analysis using a mathematical model validated by Ground Resonance Test (GRT) data. GRT is always focused to measurement of each resonance structural mode in terms of frequency, structural damping and modal shape; it has always been a critical issue causing by both significant delay about the aircraft preparation for the flights and how much time is allowed for testing. All this hardly ever fit to the massive time frame asked for GRT. This paper describes the GRT performed on the CS2 FTB#1 demonstrator and the Leonardo Aircraft Division’s validation methods applicable for the matching between experimental data and theoretical ones coming from the aeroelastic models. The validated models are used to provide initial flight clearances as concerns the aeroelastic aspects.