Method for the Measurement of the Inertia Propertiesof Bodies with Aerofoils

A method for the measurement of the inertia properties of bodies with aerofoils (such as spacecraft or aircraft) is dealt with. Two different test rigs have been realized and used to validate the proposed method. Each test rig is a spatial multicable pendulum carrying the body under investigation. The method is based on a simple procedure. The spatial pendulum is displaced from its rest configuration, and then a free motion evolves in a complex manner under the action of the gravitational field. The motion and the forces acting on the pendulum are measured, and then the inertia parameters are identified offline by a suitable and very quick numerical procedure. The proposed method does not require any dynamic excitation device, and it could be applied to measure the inertia properties of huge bodies, such as those pertaining to spacecraft or aircraft. The paper focuses particularly on how the aerodynamic forces acting on the body under investigation can influence the measurement uncertainties. Such a problem is of relevant importance for bodies with aerofoils (such as aircraft, spacecraft, or their subsystems). It is shown, both analytically and experimentally, that the developed method could be applied for the measurement of the inertia properties of full-scale aircraft or spacecraft.