IMPROVEMENT IN QUALITY OF MANUFACTURING THE LARGE-CALIBER ARTILLERY PROJECTILES (122, 152, 155) FOR GUNS WITH A RIFLED TUBE

Abstract

An analysis of the technique of manufacturing the large-caliber artillery projectiles (122, 152,155 mm) on modern screw-cutting lathes was carried out taking into account normalized tolerances for metalworking of the projectile components in accordance with international standards in force. It has been established that regardless of the qualifications of the personnel and the use of modern machines in compliance with the requirements of international standards for metalworking, the quality of projectiles from one batch can differ significantly in the value of drift. The reason for the drift of the projectile in the air is the torque of forces arising from the discrepancy in the location of the center of gravity and aerodynamic pressure in reference to the dynamic axis. Since the projectile rotates rapidly in the air, it has been suggested that because of the presence of manufacturing tolerances in metalworking, the center of gravity of the projectile can shift in the transverse plane in reference to the dynamic axis of rotation, and this is the second probable reason which, together with the first one, can affect the kinematics of the flying projectile and drift value. Thus, shocks which deviate the projectile away from the trajectory in space and have a direct impact on the value of drift are exactly caused by the presence and ratio of the forces of two torques caused by a shift in the location of the center of gravity and the center of aerodynamic pressure in reference to the dynamic axis of rotation. To reduce the range of variation (scatter) of drift values, it is proposed to improve the quality control of artillery projectiles by introducing an additional manufacturing operation into the engineering process for calibrating projectiles, and, if necessary, balancing them, by means of the determining parameter in the value of residual disbalance. Both procedures can be carried out on a balancing machine using special manufacturing equipment. Theoretically, projectiles calibrated by the residual disbalance parameter in the same weather conditions of firing will have a reduced range of variation (scatter) of drift values, but it is desirable to check this in practice.