Missile tail fin assembly

Abstract

An improved missile tail fin assembly. The missile utilizes four tail fin assemblies, each assembly comprising a fitting having three locking portions, each of which comprises a gudgeon having a pair of locking teeth, and a fin having mating recesses for the locking portions. A portion of the material associated with recesses of the two forward locks of each fin is removed, leaving clearances which permit limited rotation about the fin pivot axis in one direction only. When the fin is loaded in a direction to produce clockwise torque, all three locks which form the lock assembly are loaded approximately equal and this locates the elastic axis of the tail lock approximately just aft of the center of pressure which produces a small increase in cant angle with load. When the tail fin is loaded in the direction to produce a counterclockwise torque, the aft lock of the assembly will take all the torque. This moves the elastic axis further aft thus producing a larger increase in cant angle with load. The difference of these two changes in cant angle will be a net torque in the counterclockwise direction. When the deflection at the two forward lock positions reaches the clearance limit, all three locks will pick up the load and the surface will have the same stiffness as an unmodified tail fin.