The Survivability Of Helicopters To Rotor Blade Ballistic Damage

This paper describes a program to investigate the survivability of helicopters to rotor blade ballistic damage. The ballistic threat used in the investigation was the 23mm HEI-T. Ballistic damage to the rotor blade will alter the dynamics of the helicopter, impair the strength of the rotor, and change the aerodynamics in the region of the damage. These results were studied parametrically and the results are presented. A Survivability Model was developed to compute the damage inflicted by the projectile and to assess the capability of the helicopter to survive. This required developing a new helicopter dynamic simulation program and separate fatigue analyses for metal and composite blades. Ballistic and fatigue tests were performed to evaluate predictions made by the Survivability Model.