Experimental Study of Automatic Weapon Vibrations when Burst Firing

The article presents a new approach to finding the dynamic characteristics of automatic weapons, mainly in case of burst firing. The experiments were tested out on a 30 mm AGS-17 grenade launcher mounted on a tripod in the event of a shot. The obtained results are the basis for evaluating the firing stability of an automatic weapon when burst firing, which allows modernising the existing weapons and evaluating similar weapon systems. Furthermore, the outputs can be used to validate a dynamic model of an automatic weapon system mounted on the tripod. The procedure can be used as an example of practical technique and methodology for other weapon systems.

Constructional Aspects for Safe Operation of 120 × 570 mm Ammunition

This paper provides a characteristic of the design of 120 × 570 mm tank ammunition with particular reference to the cartridges in service in the Polish Army. The presentation of the design and technological details was primarily focused on emphasising their influence on the phenomena occurring or likely to occur during the process of ammunition operation, and to a much lesser extent related with the reference of the characteristics of the performance of the ammunition. Due to the sheer bulk of this subject matter, this paper narrowed the issues of ammunition primarily to the aspects of entry into service, transport, storage, and operation of the specified ammunition cartridges. During these operational stages, there was major focus on the issues of ammunition safety and reliable performance. Note that these aspects are not exhaustive for the topic; this paper also serves as an introduction to a future paper which will deal with safety issues during combat operation using the 120 × 570 mm tank ammunition cartridges.

Concept MSBS GROT Rifle Upper Receiver Shield to Protect Against Foreign Objects

This paper presents a concept for shielding the MSBS (Modular Firearms System) Grot rifle upper receiver against foreign objects. The concept guidelines involve feedback from Grot operators concerning the regular operation of the rifle plus an extensive analysis of desktop patent research into foreign debris shields (or dust shields) for protection of the upper receiver interior in firearms. The completed patent desktop research included solutions used with automatic, semi-automatic and non-automatic firearms. The research work drove the formulation of the requirements for an upper receiver dust shield for the 5.56 mm calibre MSBS Grot rifle as part of the ongoing improvement process. This paper presents three concepts of the carrier charging handle assembly dust shield (for the protection of the upper receiver against foreign objects) for the MSBS-5.56 rifle system. The concepts described vary in terms of the level of structural complexity of the dust shield, and the extent of the modifications required to the upper receiver of the rifle. With test units of the upper receiver dust shield manufactured and comparative tests completed on the three concepts, the version selected should be the one which improves the protection of the rifle internals from foreign objects found in the local environment, including sand, clay, silt, and mud, the latter being an aqueous suspension of these particles.

G-Force Test Stand for the Evaluation of Weapon Component Strength

This paper discusses the design of a G-force test stand intended to examine of the effects of mechanical loads present during firing of a weapon and applied to the electronic components contained in the 155 mm calibre guided projectile. The G-force test stand is used to develop and test the effects of using high mechanical loads by decelerating a test specimen through the use of a purpose-designed fender assembly. For the purpose of testing, it is irrelevant whether a load is developed by acceleration or deceleration of the test specimen, as a test result obtained by the deceleration of a test specimen is equivalent to a test result obtained by the acceleration of a test specimen, as used in a 155 mm calibre artillery guided projectile. The G-force test stand was used to test and determine the velocities developed by the test specimens and the G-forces applied to them. The maximum velocity to which a test specimen was accelerated was approx. 72 m/s. The test stand was able to propel the test specimens to velocities an order of magnitude higher than the velocities obtained with a Kast and Masset ram. The tests were performed with rubber and copper fender assemblies. The effect of the specific fender used was demonstrated on the trend of the generated G-force. The test stand could develop G-forces in excess of 10,000 with a duration of more than 500 µs.

Quasi-Static and Dynamic Mechanical Properties of a Ti-6Al-4V Titanium Alloy Produced Using Unconventional Manufacturing Methods

The purpose of this paper was to determine the mechanical properties of a Ti-6Al-4V titanium alloy produced by traditional CIP (Cold Isostatic Pressing) and by LENS (Laser Engineered Net Shaping), an additive manufacturing process. A reference material, being a commercial Ti-6Al-4V alloy, was also tested. The strength test specimens were produced from a high-quality, Grade 5 titanium powder. Each specimen had its density, porosity, and hardness determined. Compression curves were plotted for the tested materials from the strength test results with static and dynamic loads. These tests were performed on an UTS (Universal Testing Machine) and an SHPB (Split Hopkinson Pressure Bar) stand. The test results obtained led to the conclusion that the titanium alloy produced by CIP had lower strength performance parameters than its commercially-sourced counterpart. The LENS-produced specimens outperformed the commercially-sourced alloy both in static and dynamic load conditions.

Dilatometry of Steel for the Production of 5.56 mm Calibre Rifle Barrels

During high rates of fire, the bore of the firearm barrel is exposed to high temperatures. This exposure induces structural changes in the barrel material, which is especially significant for the substrate of the galvanic chrome plating. The alloy steel grades used currently for firearm barrels, when exposed to heating above the ferrite stability limits, develop a phase transition with a discrete negative change in the material volume, which results in typical crazing in the bore. This effect is destructive to the galvanic chrome plating, leading to a loss of adhesion, which reduces the ballistic performance of the firearm, especially its muzzle velocity. This can be prevented by manufacturing barrels from steels having a limited range of phase transitions. The primary method for determining the presence of distinct volume changes in steel due to phase transition is dilatometry over a wide temperature range, which includes the interval within which the barrel bore is heated. This paper presents the dilatometry results for four steel grades, which included a steel grade currently used for firearm barrels, and an analysis of the effects of phase transition on the degradation of the barrel bore.

A Method for Predicting Efficiency of Perforated Muzzle Brakes

This paper presents a method for predicting a value of a gasdynamic efficiency coefficient for perforated muzzle brakes. The method is based on the interior ballistics modelling for determining gasdynamic flow parameters at the brake inlet and 2D modelling the processes inside the brake with treating vents as circumferential slots. The modelling provides information about the mass flux time changes at the inlet and at the outlet of the brake. Using this information, the mass partition coefficient values and the gasdynamic efficiency coefficient values are calculated. It has been shown that the mass partition coefficient establishes very quickly and it is determined only by the geometry of the brake. The gasdynamic efficiency coefficient establishes after a relatively long time, what demands carrying out calculations for a relatively long time period. However, it has been shown that this problem can be solved by making use of the established ratio of mass fluxes at the outlet and the inlet. So, flow parameters’ values at the inlet are sufficient for determining the gasdynamic efficiency coefficient to the moment of attaining the final value. It has been shown that this value depends on the ballistics and on the vents inclination angle.

Review of Modern Helicopter Constructions and an Outline of Rotorcraft Design Parameters

This work contains the results of a modern helicopter construction analysis. It includes the comparison of almost seventy rotorcraft constructions in terms of size in line with EASA requirements – large and small helicopters. The helicopters are also divided because of a mission purpose. The proposed division for large aircrafts is: transport, multipurpose, attack and for small aircrafts: observation, training, and utility. The aircraft construction features are described. Average dimension values of airframes and rotors are shown. Helicopter rotor arrangements are presented in terms of an operational purpose. Next, the rotorcraft design inputs are described. The mathematical formulas for design inputs are given. The ratios are calculated and gathered for the compared aircrafts. Correlation between the analysed parameters is presented on charts. Design inputs are also presented in the paper as a function of MTOW. The function trends are determined to provide an evaluation tool for helicopter designers. In addition, the parameters are presented as possible optimisation variables.

Dynamics of Short Recoil-Operated Weapon

In this article, the authors mentioned the function of short-recoil-operated weapons with a vertical sliding-wedge breechblock. The dynamic simulation was conducted and then the results were compared with the corresponding experimental data to verify reliability of the model. The model is calculated and tested out on the 37 mm twin anti-aircraft gun. Besides, the article presents the effect of some structural parameters on functionality of the automatic weapon. The reported results are an important theoretical basis to determine the rate of fire and the forces acting on the guns. The movement of the breechblock also affects stability of the weapon and can therefore be used to a math model or to simulate the movement of the weapon. Calculated and verified data could be used for the design of an automatic firing system as well as for solving vibration on automatic guns when burst firing.

Probability of an Intermediate (Reduced Operational) State

This work examines with the form of the well-known sum: p + q = 1 – which is the sum of the probabilities of opposite events, in particular: the sum of the probabilities of the operational and non-operational (failure) states of a single element (a creation characterised by one output and any number of inputs). It was found that without significantly compromising the accuracy of the previous analyses, it was possible to introduce an additional component to the sum: iiipq3, a component that embodies the probability of an intermediate state, or a reduced operational state. With a constant value of the sum of the components in question, their variation as a function of probability q was determined, following which in the function of the same variable the variation of the entropy of an element's i state was examined using Chapman-Kolmogorov equations; here the focus was on investigating the intensity of the transition from the operational state to the non-operational state or an intermediate state, and from an intermediate state to the non-operational state. The meaning of intermediate probability was also referenced to the object: its diagnostic program, the entropy of structure, the full set of discriminable states, and the relevant transition intensities. It became indispensable in this respect to describe the object using the language of graph theory, in which the basic concepts are layers and an availability matrix. It should be noted that the subject object is an entity that comprises a set of individual elements, with a number and structure of connections that are consistent with the purpose of this entity.