Abstract: An improved procedure for collecting experimental data reflecting the behavior of a time varying aerodynamic parameter at an airfoil in a cascade of airfoils vibrating harmonically in a fluid stream including the steps of vibrating the center airfoil of the cascade at a selected frequency and amplitude while each of the other airfoils is held rigid, measuring the time varying parameter at the center airfoil and expressing it as a function of the position of the center airfoil in its vibratory cycle, vibrating each of the other airfoils in turn at the selected frequency and any amplitude while maintaining all the remaining airfoils rigid, measuring the time varying parameter at the center airfoil for each individual airfoil vibration and expressing the measurement as a function of the position of the individual vibrating airfoil, expressing the position of each individual vibrating airfoil as a function of the position of the center airfoil, and combining the time varying parameter expressions and position exp