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Weapon Design Practice
Published in Donald E. Carlucci, Sidney S. Jacobson, Ballistics, 2018
Donald E. Carlucci, Sidney S. Jacobson
Recoil is generated on the gun by the reaction of its moveable parts to the impulse of the gas pressure both while the projectile is in the tube and while the propelling gases are being exhausted after the projectile exits. After projectile exits, we may simplify the actual process to one that assumes that the breech pressure decays linearly with time. This period is called the gas exhaust aftereffect and is shown in Figure 5.8.
Threat/vulnerability assessments and risk analysis
Published in Michael L. Madigan, First Responders Handbook, 2017
Firearms: used in a ballistic tactic to attack facility assets from a distance and in the forced-entry tactic to overpower guards. These include pistols, rifles, shotguns, and submachine guns, both military and civilian. Weapons capabilities are outlined in the Security Engineering Manual.
3D printing of gun propellants based on laminated object manufacturing
Published in Materials and Manufacturing Processes, 2022
Moru Wang, Guorui Jin, Weidong He, Fengqiang Nan
The combustion of the gun propellants in the chamber of the weapon produces gases that form a high pressure to propel the projectile. The combustion performance of gun propellants is therefore reflected in the pattern of pressure changes. The pressure history (p-t curve) of rosette-shaped 61-perf double-base gun propellant could be gained directly from the closed vessel test, as shown in Fig. 9a. It can be seen from the figure that the printed gun propellant with a loading density of 0.16 g·cm−3 reached a pressure of 205.7 MPa in 12.8 ms. This means that the printed gun propellant had a high energy level.
Science And Technology of Aircraft Seat Ejection: Advanced Concepts
Published in Cogent Engineering, 2022
The modern fighter seat ejection is installed with explosive cartridges. They are installed on the main gun in the aircraft cockpit. The main gun is propelled by energy derived after propellant burning inside it. During an emergency, these cartridges are used to operate the main ejection system when the pilot pulls the firing handle situated between his thighs. The whole system is fully automatic once initiated by the pilot. As the sear is withdrawn from the firing mechanism, the pin strikes the cap. This generates the flash and ignites the primary cartridge. The resultant flash passes through the flash holes and ignites a booster composition. This subsequently ignites the propellant. The pressure developed inside the primary cartridge break the copper foil and releases the gas pressure. The telescopic tube gets expanded. The ports of the intermediate tube are uncovered due to the expansion of the telescopic tube. This is the only means to rescue the pilot in the emergency from the disabled aircraft within the shortest possible time. The principle of the telescopic gun is used for the ejection of the pilot. The system comprises the innermost tube, an intermediate tube and an external tube. This concept helps to avoid the requirement of a single tube considering the space constraint in the cockpit. The outermost tube is fitted to the aircraft structure. The various stages of the expansion of the telescopic tube with the total mass (pilot and seat) till the expansion of the full system are illustrated in Figure 4. The actual position of the telescopic tube in the steady-state in the aircraft system is depicted at stage 1. The primary cartridge with a firing mechanism is fitted inside the innermost tube. The first primary cartridge is fired by the percussion firing mechanism. The expansion of an intermediate tube takes place due to a high temperature and pressure generated by the propellant burning inside the primary cartridge, as indicated at stage 2. The mass is lifted upward and secondary cartridges are fired as these cartridges are exposed to high pressure and temperature because of the port opening. This is shown at stage 3. At the end of the stroke, the pilot with an innermost tube is ejected out. This is shown at stage 4. During the seat ejection, the pilot will experience the force. Those forces are well within the permissible physiological limits. The idea behind the limitations is that the human body comprises a heterogeneous man with solid, liquid, and visco-elastic components. Each system has a different response to accelerative force and different systems will fail under the different loading conditions. The ejection velocity achieved using a telescopic tube is not sufficient to clear the aircraft’s tail fin. Therefore, rocket motor with multiple rocket units having a nozzle arrangement situated below the seat pan gives additional thrust for the safe escape of personnel from the disabled fighter aircraft in the shortest possible time. The rocket motor is illustrated in Figure 5. The speed for the aircraft is 1,300 km/h, and the force experienced by the pilot is well within permissible physiological limits (acceleration 12–14 g).