Ballistic Design Support Tests - A Tool For Helicopter Vulnerability Reduction

The importance to the designer and to stress, weights, and vulnerability analysts of ballistic design support tests early in a new attack helicopter program are discussed. Such tests provide data for preliminary evaluations of various design approaches directed towards reducing helicopter vulnerability to ballistic impact. The significant differences between design support tests, the subject of this paper, and those ballistic tests contractually required under the Airworthiness Qualification Specification are noted. A number of specific tests using 12.7mm API and 23mm HEI threat projectiles, in support of the YAH-64 Advanced Attack Helicopter, are discussed and illustrated. These tests simulated the blast/fragment barrier separating the pilot and co-pilot/gunner, various critical control components, the tail rotor drive shaft, integral armor sleeves protecting bearings, main rotor control clevises, and the fuselage structure. Some generalized statements on test results, to the extent they are supported by available data, are presented.