The Improvements of Ballistic Characteristics of Artillery Projectiles of 152 and 155 mm Calibers

Abstract

The existing methods of manufacturing artillery projectiles with calibration and markingonly in one parameter for measuring the total mass by statically weighing do not take into accountthe dynamics when a projectile moves in the air, namely, the dynamic unbalance of the mass owing tounevenly distributing the mass throughout the geometric shape of the projectile. When flying alonga ballistic trajectory, projectiles rotate in the air with a high angular velocity in the range of 200–500rev/min and, therefore, they are similar in the dynamics of the rotating motion to the rotation of rigidrotors. Based on the presence of manufacturing tolerances in the metalworking of the body, artilleryprojectiles can have dynamic unbalance and a large amount of unbalance, which can exceed theallowable norm for rigid rotors by 15–20 times and unpredictably affect the dynamics of a projectilewhen moving along a ballistic trajectory. The solution to this problem is seen in the improvement ofthe methods being used for manufacturing artillery projectiles by performing an additional manufacturingoperation for correcting (diminishing) the unbalance vector, which will reduce the lateraldeviation and drift of the projectiles in flight as well as stabilize their dynamic parameters whenmoving along a ballistic trajectory in the air, and that will certainly lead to an increase in the rangeof the projectiles and enhancement of the accuracy of hitting the target. The article proposes severaloptions for the practical implementation of the manufacturing operation for correcting the unbalancevector of projectiles in one plane. When applying the method of balancing the projectiles by addingmissing metal (mass), it is proposed to place the corrective weight in a special “corrective groove” onthe outer surface of the projectile body, which can be preliminarily made on a metalworking machineduring the general processing of the projectile body. To ensure the strength of fixing in the grooves ofthe corrective weights from the influence of the pressure of powder gases on them when firing froma gun, it is proposed to make the geometrical profile of the groove in the cross section of a trapezoidalshape of the dovetail type. When applying the method of removing excess metal (mass), it is proposedto make holes on the outer surface of the projectile body by milling (or drilling). The mass and place (angle) of the correction, the geometric dimensions, and the number of corrective weights or correctiveholes shall be preliminarily determined in the course of balancing the projectiles on a balancingstand. It is proposed to introduce the marking of projectiles in five classes through two parametersof mass and their deviations from the norm: the first of which is the measurement of the total massof the projectile in statics, and the second one is the measurement of unbalance of the mass of theprojectile in the form of the amount of unbalance in dynamics.Keywords: projectiles, ballistic characteristics, balancing, calibrating, unbalance vector