Development of a novel active muzzle brake for an artillery weapon system

Abstract

A conventional muzzle brake is a baffle device located at some distance in front of the muzzle exit of a gun. The purpose of a muzzle brake is to alleviate the force on the weapon platform by diverting a portion of the muzzle gas resulting in a forward impulse being exerted on the recoiling parts of the weapon. A very efficient muzzle brake unfortunately gives rise to an excessive cover pressure in the crew environment due to the deflection of the emerging shock waves. The novel active muzzle brake of this dissertation is based on a concept developed by Qinetiq. The novel technique involves the main brake chamber being closed for a very short period of time after the projectile has uncorked from the barrel eliminating the main emerging shock wave from developing to full strength with the result that the novel muzzle brake gives rise to a very low over pressure. This has the advantage that the gun crew suffers from less strain to the ears and vulnerable organs. Inherently the novel brake suffers a loss in efficiency due to the chamber being closed for a while and a method had to be developed to improve the efficiency of the conventional part. This dissertation deals with the development of a novel active muzzle brake intended for a 155 mm artillery weapon, but scaled to an 88 mm 25 pounder G 1 as an interim phase. Several constraints and requirements have been set regarding the physical properties and performance criteria of the prototypes. The interim phase of the project was executed within three years in which six prototypes were developed and evaluated. Major challenges in the development were to design a control and restoring mechanism that would survive the harsh conditions at muzzle exit and to enhance the efficiency. The establishment of linear movement of the closure mechanism and friction springs as the restoring mechanism was a major breakthrough in this respect. The first four prototypes were designed using empirical data and first order modeling as background while a CFD technique was used to refine the last two prototypes. Of the six prototypes developed, the first two were unsuccessful in demonstrating the novel technique. The one was unable to survive the muzzle exit conditions and the control mechanism on the second muzzle brake opened too soon. Of the remaining four, the last prototype passed all the specified constraints and proved to be a candidate for the 155mm upgrade. Not only was the structure robust enough, the general appearance of the novel muzzle brake is futuristic. This prototype is also a candidate if a much more efficient muzzle brake, with similar over pressure characteristics of a less efficient muzzle brake, is needed.