The present paper describes research activities related to the Active Aeroelastic Aircraft Structures Project, fulfilled by Politecnico di Milano, dealing with the aeroelastic demonstrator named X-DIA. This aircraft is a onetenth geometrically and dynamically scaled model of a regional transport airplane, and it has been built to become a wind-tunnel benchmark for experimenting with new aeroelastic concepts. All movable foreplane surfaces and wings with distributed multiple control surfaces are here installed to improve overall aeroelastic response and thus to improve airplane stability and even fuselage flight comfort. An identical location of accelerations and forces-based control system has been implemented: numerical and experimental results show a remarkable capability of this\ud device in damping fuselage bending and torsion modes. The following pages will provide information about the research project, describing methodologies adopted and experiment results taken in wind-tunnel testing

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Nomenclature a, b, c, d, e, f = active control law parameters b = damping of aileron with actuation and additional regulator EPa = Young's modulus f, G, g,regulator force amplitude Hm = height k = stiffness of aileron with actuation and additional regulator kN:m −1 = spring constant mkg = mass m = mass of aileron with actuation and additional mass of regulator n1 = load factor ny1 = Poisson's ratio Rm = radius ts = time xm = aileron actuation rod deflection ym = spring deflection y 0 m = spring initial stretch

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This article deals with aeroelastic certification analyses of the new-generation Czech twin turboprop utility aircraft. The article is focused on the first phase of analyses before the ground vibration test (GVT) of the prototype. It describes the analytical model as well as the used tools and methods. The description of specific blocks of analyses follows afterwards. It includes the preliminary flutter analyses, static aeroelastic analyses (control reversal and divergence), modal analyses, and large parametric flutter analyses (surface, control surfaces, and tab flutter). The flutter characteristics of the structure with respect to changes of the selected parameters are presented. Furthermore, the preparation of the GVT (i.e. the optimization of the exciter and accelerometer positions based on the analytical results, and the whirl flutter analyses by means of an optimization-based approach to find the critical stability boundaries are explained). Finally, the performed activities are summarized and the next phase of aeroelastic certification (GVT, final analyses, and flight flutter tests) and the aircraft development are outlined.