Metal to replace gunpowder
Already that century is the basis of the vast majority weapons is gunpowder. Until now, the invention of the ancient Chinese has not lost its relevance and will not lose it in the near future. Moreover, the very concept of throwing ammunition with the help of explosive release of gases with a special mixture will remain practically applicable even when mankind will also fight in space. In this case, firearms, with a number of relevant modifications, will be one of the most formidable arguments of the space forces. If the laser beam can be “fought off” with a suitable mirror coating, then kinetic ammunition will be stopped only by armor, which makes the equipment heavier, and therefore increases the cost of its launch into space. Only by the time of the first fights in space could metallurgy have time to make new light sorts of armor. Not to refuse on this occasion the shells, hitting the target due to the kinetic energy? Yes, and on Earth there is still where to fight.The existing powder ammunition has reached its limits. Weapon chemistry has already “welded” almost all possible types of gunpowder with maximum propelling properties. The heat of combustion of the most "strong" varieties does not reach 4 MJ / kg. Accordingly, it would be logical to use other substances instead of gunpowder, with large numbers of heat of combustion, for example, metals, which have this indicator many times more. So, to achieve the same effect, you can put in the sleeve less active substance. This concept of ammunition was called pneumoelectric cartridge / projectile. Now we will consider this idea in more detail, and it will become clear why it was called this way.
What is a pneumatic cartridge. In appearance, it vaguely resembles ordinary powder, although it has smaller dimensions, especially length. Instead of a capsule, a flammable element (a spiral or something similar) is placed in it, and instead of powder there is metal powder and a certain amount of compressed oxidant gas (oxygen or even fluorine). There is also a certain amount of another gas, it may be a substance from the right edge of the periodic table - an inert gas, or an excess amount of oxidizer. The principle of operation of the cartridge is simple: the electric igniter of the weapon applies voltage to the igniting element, which ignites the metal powder. It, in turn, burns in an oxygen atmosphere at high speed and produces a large amount of heat. Since the volume of gases generated during combustion is insufficient for firing, the heat heats up the inert gas and that, respectively, adds the missing pressure. Combustion products together with heated inert gas push the bullet out of the cartridge and the barrel. "Electro" in the name of the ammunition says about the method of ignition, and "pneumatic" - about the method of acceleration of the bullet. The fact is that the main impulse is given to it by a heated and expanded “additional” gas.
Pneumoelectric cartridges in the "laboratory conditions" have the following advantages over powder:
- large specific power charge. This will allow both to increase the initial speed of the bullet / projectile, and to reduce the size of the ammunition while maintaining the characteristics. Accordingly, it is possible to increase the capacity of the ammunition of an individual fighter.
- no need to spend part of the energy of gases on the work of automation. It should be noted that this thesis requires the use of batteries of sufficient capacity and power on weapons. If they are not there, then instead of the gas engine that is traditional for powder automatons, a generator with suitable characteristics can be installed, which will ensure the work, or you can keep the usual gas automatics adapted to the new working conditions.
- simplifying the design of the weapon and reducing the number of moving parts. Completely get rid of the latter will not succeed, but the layout and operation should become easier.
- complete failure of any external power source or built-in battery. When using the relevant material of the igniting spiral in pneumoelectric weapons, it is possible to use a piezoelectric element associated with a trigger as a generator. However, in this case, you will have to either take away some of the gases for the gas engine, or do mechanics similar to double-action revolvers, where when you press the trigger the drum rotates, the trigger is cocked and lowered.
Nevertheless, the creation of practically applicable pneumoelectric ammunition requires the solution of a number of problems:
- thermal. The high heat of combustion of the metallic charge of the cartridge requires the use of new materials with better heat resistance. Otherwise, if the barrel of a weapon, etc. to do with current technology, a gun or machine gun can melt down or even catch fire in the hands of the shooter. Also, a metal barrel, under certain circumstances, can also react with an oxidizing gas or its excess, intended to disperse a bullet.
- chemical and abrasive properties. In the pneumoelectric weapon, as in the powder, carbon deposits are formed. Moreover, the soot from the metal charge will have greater abrasive properties than powder. This problem can be solved in conjunction with the previous one by applying special barrel coatings like Teflon. Additionally, the weapon can be equipped with a purge system with “outboard” air, which will partially cool and clean the barrel. Also, metals can be replaced by other substances whose oxides have a lower hardness.
- reaction time. The burning rate of most metals under normal conditions is insufficient for use in weapons "as is". To accelerate the combustion reaction is proposed using catalysts, changing the shape or size of the particles of the working substance. As an alternative, you can consider the increased pressure of the oxidant gas or even use it in a liquefied form.
- features of the electrical circuit. The use of a large number of electrical parts in weapons requires appropriate sealing in order to avoid short circuits and failure. For this, the electrical igniter assembly can be made as a separate unit having a good seal.
For example, the entire electrical “stuffing” on a pneumatic electric weapon with a gas engine of automation (piezoelectric element connected with the trigger, a set of capacitors and contacts of the igniter) can be placed in a single case, additionally filled with epoxy resin or other similar material. However, the repair node will have to perform a complete replacement.
Despite the fact that pneumoelectric charges do not constitute an explosive in the classical sense, they can be used not only for throwing ammunition. One of the “alternative” applications of pneumoelectric weapons is to increase the effectiveness of high-explosive fragmentation projectiles. In this connection, the following example is often cited: the surface of the internal cavity of the projectile is made of zirconium or of an alloy based on it, and the cavity itself is filled with oxygen or oxygen mixed with another gas. In a twenty kilogram-like projectile, if it hits the target, it is only due to the impact that the combustion reaction can start, due to which per kilogram of oxygen accounts for about 2,8 kg of reacted zirconium. During the reaction with this amount of the starting materials, about 80 MJ of thermal energy is released, which corresponds to approximately 20-22 kilograms of TNT. The remaining three or four kilograms of oxygen, for example, heat up sharply and tear up the shell of the projectile, scattering the surrounding space with shrapnel and causing the surrounding objects to ignite. Also, instead of an excess amount of oxygen, a more effective oxidizing agent fluorine or heat-resistant toxic substances can be pumped into the projectile.
However, the greater interest is not the substance used in the projectile, but its quantity: in the specified example, the projectile weighs 20 kg, and the reacted substances are less than four, which is less than 20% of the total mass. If we add to them the four kilograms of substances that lead to the rupture of the projectile, then all of its chemical part is only 40%. Thus, firstly, you can increase the power of the munition, keeping the same dimensions, and secondly, to create fragments, a sufficient amount of metal remains comparable to existing projectiles. But the most interesting fact in the practical aspect is that the zirconium-oxygen pneumoelectric projectile is similar in mass and heat indicators to a projectile entirely made of TNT.
As for the reliability of the projectile, it is unlikely that the designers, when it comes to at least prototypes, will rely on the heat generated upon impact. It will be much more profitable to use an electric or chemical fuse, which releases the energy necessary to start the reaction. In addition to the creation of artillery shells, it is possible to create hand grenades, mortar mines, anti-tank mines and aviation bombs with a similar principle of action.
However, despite all the advantages of the pneumoelectric weapon and the patent on the principle of action, the work on the topic is going extremely slowly and sluggishly. Coupled with a whole range of problems that prevent the use of pneumoelectric ammunition, this slowness does not give reason for optimism. If all the works go the same way as now, then the first prototypes will be dealt with by the year 2020, and then, with good luck and no additional difficulties have arisen.
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