Nonlinear Response of Airfoil Section with Control Surface Freeplay to Gust Loads

A nonlinear response analysis of a typical airfoil section with control surface freeplay excited by periodic gust loads in low subsonic flow is presented along with a companion wind-tunnel test program. The analytical model uses Peter's finite state model for the two-dimensional aerodynamic flow over the airfoil (Peters, D.A., "Finite-State Airloads for Deformable Airfoils on Fixed and Rotating Wings," Symposium on Aeroelasticity and Fluid/Structure Interaction, American Society of Mechanical Engineers, Winter Annual Meeting, Nov. 1994, rev. 3, May 1996).