An elastic element of the forced oscillation apparatus for dynamic wind tunnel measurements

In this paper an elastic element of the forced oscillation apparatus for dynamic measurements in the T-38 wind tunnel is described. The forced oscillation apparatus consists of the elastic element, dynamic balance, actuator arm, hydraulic driving mechanism and sting. The front part of the apparatus is installed into a model during wind tunnel measurements. This element supports large aerodynamic loads and enables primary oscillatory motion of wind tunnel models. It has to enable high compliance in the apparatus primary rotational degree of freedom and high stiffness in the secondary degrees of freedom. The elastic element is formed from a pair of symmetrical cross-flexures with variable cross-section of the strips. The oscillatory motion sensor is realized on the cross-flexures. This sensor provides clean referent signal for data reduction in the dynamic wind tunnel tests.