Analysis of parachute opening dynamics with supporting wind-tunnel experiments

The equation of motion for parachutes inflating under finite mass conditions in a horizontal flow wind tunnel is established and organized in view of the nonsteady terms of canopy size, velocity, included and apparent masses, and the time derivatives of these terms. Windtunnel experiments are described, the results of which yield graphical and numerical time functions for the terms of the equation of motion. In the test range under investigation, these functions appear to be unique. The wind-tunnel results are compared with full-size test information and certain identities are shown. The numerical functions are substituted in the equation of motion and force-time histories calculated. Calculated and measured forces agree fairly well, and the calculations show the contributions of the various terms to the total force.