Integration of Grid Fins for the Optimal Design of Missile Systems

Abstract

Grid fins are unconventional missile control and stabilization devices that produce unique aerodynamic characteristics that are vastly different from that of the conventional planar fin. History has shown that grid fins are able to achieve much higher angles of attack than planar fins without experiencing any effects of stall. They are also able to produce much lower hinge moments than planar fins, which allows for the use of smaller actuators for fin control. However, the major drawback of grid fins that has prevented them from seeing more applications in missile control is the high drag that is associated with the lattice structure, which is substantially larger than that of a comparable planar fin. Despite the high drag produced by grid fins, there are still several applications where the grid fin is an ideal candidate for missile control. One such application is the maximization of the target strike capability of a missile that is released from an airplane at a designated altitude. The goal of this work is to integrate a set of grid fin aerodynamic prediction algorithms into a missile system preliminary design code in an effort to maximize the target strike area of a missile using both planar fins and grid fins as aerodynamic control devices. It was found that a missile system using grid fins for aerodynamic control is able to strike a larger target area with a higher degree of accuracy than a similar missile system using equivalent planar fins for aerodynamic control.