Internal Ballistic Theory of the One-Charge, Variable-Vent Mortar

(Эдвард Л. Лайнс, Карл Дж. Кампэгнуоло. Внутребаллистическая теория миномета с одним пороховым зарядом и зарядной камерой переменного объема).Technical report. -Adelphi USA: Harry Diamond Laboratories, 1977. – 37 p.This paper presents a study of the interior ballistics of the one-charge mortar. The one-charge mortar is a design which was recently granted a U.S. Patent. The essential idea is of a vent of variable cross section in the mortar tube. When the projectile is fired, the vent permits part of the high-pressure combustion gases to exhaust. The area of the opening controls the muzzle velocity. This concept is believed to be an improvement over the design of existing mortars, such as the 81-mm mortar, where the muzzle velocity is controlled by the amount of propellant attached to the round. If a lower muzzle velocity is desired, the ammunition handler manually removes and discards the excess charges before loading. In the one-charge mortar concept, the propellant is not handled at all. Any adjustments are made by removing the lever or handle that controls the vent area.Contents:
Introduction.
Derivation of governing equations.
Equation of Motion of Projectile.
Burning Solid Propellant.
Combustion Gases in the Mortar Tube.
Governing Equation System and Solution Procedure.
Results.
Description of 81-mm Mortar.
Results for Basic Charge.
Other Design Considerations.
Conclusions.