Railguns are a type of linear motor device that utilizes electromagnetic force to launch high velocity projectiles. Typically designed as weapons, they rely on the projectile's high speed, mass, and kinetic energy to inflict damage, without using any explosives. The railgun operates through a pair of parallel conductors known as rails, which propel a sliding armature through the electromagnetic effects of a current that flows down one rail, into the armature and then back along the other rail.
One of the most significant advantages of railguns is their ability to impart very high kinetic energy to a projectile utilizing electromagnetic forces. Explosive-powered military guns cannot easily achieve a muzzle velocity of more than approximately 2 km/s (Mach 5.9), while railguns can exceed 3 km/s (Mach 8.8). The range of railguns may also surpass that of conventional guns. The force of a projectile depends on its kinetic energy at the point of impact, which can be significantly higher for a railgun-launched projectile than for a conventionally launched one of the same mass. Furthermore, railguns do not require explosive propellants or warheads, and their projectiles are relatively inexpensive compared to those of traditional weaponry.
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Test firing at the United States Naval Surface Warfare Center Dahlgren
Division in January 2008 |
Despite decades of research and development, railguns are still primarily at the experimental stage. It remains to be seen if they will be deployed as practical military weapons in the near future. The use of electromagnetic propulsion systems as opposed to chemical propellants for weapons applications must consider their durability, availability, and economics, as well as the complexity and energy demand of the pulsed power supplies required for electromagnetic launcher systems.
Working Principle and Specifications of Railguns
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| How does a railgun fire? |
A railgun is an advanced weapon system that accelerates projectiles to high speeds using electricity and magnetic fields. Unlike traditional electric motors, railguns require no additional field windings or permanent magnets. Instead, a single loop of current is used to produce accelerations and muzzle velocities that require high currents, typically on the order of one million amperes. Some railguns use augmented configurations to increase the magnetic field and reduce the current required for acceleration. The armature of a railgun can be metallic sliding conductors, plasma, or hybrid. Military railgun designs aim for muzzle velocities in the range of 2,000–3,500 m/s with muzzle energies of 5–50 megajoules. Railguns require high launch currents of a few million amperes, and their power supply can be provided by capacitors, pulse generators, or disc generators. The elimination of explosives from a railgun weapon system decreases its vulnerability to enemy fire, making it an attractive option for military applications.
Video: How the railgun works
Electric Gun Technology in the United States Armed Forces
The United States Armed Forces has been interested in developing electric gun technology since the late 20th century. These guns do not require propellants, making them safer to operate and reducing logistics costs. Railgun systems, in particular, have the potential to increase the velocity of projectiles, thus increasing accuracy for anti-tank, artillery, and air defense by reducing the time it takes for the projectile to reach its target destination.
The U.S. Army invested more than $150 million in electric gun research in the early 1990s. The University of Texas at Austin Center for Electromechanics developed military railguns capable of delivering tungsten armor-piercing bullets with kinetic energies of nine megajoules. Nine megajoules is enough energy to deliver 2 kg of projectile at 3 km/s. The United States Naval Surface Warfare Center Dahlgren Division demonstrated an 8 MJ railgun firing 3.2 kg projectiles in October 2006, as a prototype of a 64 MJ weapon to be deployed aboard Navy warships. However, one of the problems that the Navy faced in implementing a railgun cannon system was that the guns wear out because of the immense pressures, stresses and heat generated by the millions of amperes of current required to fire projectiles with megajoules of energy. Despite this, the development of railguns continued, and in 2007, BAE Systems delivered a 32 MJ prototype (muzzle energy) to the U.S. Navy.
Video: The Railgun firing test achieved a velocity of Mach 7
On 31 January 2008, the U.S. Navy tested a railgun that fired a projectile at 10.64 MJ with a muzzle velocity of 2,520 m/s. The Office of Naval Research set a world record by conducting a 33 MJ shot from the railgun in December 2010. The U.S. Navy had plans to integrate a railgun that has a range of over 160 km onto a ship by 2016. As of 2014, the only U.S. Navy ships that could produce enough electrical power to get the desired performance were the three Zumwalt-class destroyers. They could generate 78 megawatts of power, more than is necessary to power a railgun.
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| Zumwalt-class destroyers |
However, the Zumwalt has been canceled, and no further units will be built. Engineers are working to derive technologies developed for the DDG-1000 series ships into a battery system so other warships can operate a railgun.
US Navy Cancels Electromagnetic Railgun Program After 15-Year Investment
The US Navy has announced that it is halting the research and development of its electromagnetic railgun (EMRG) program after investing approximately $500 million over the past 15 years. The decision to pause the program is attributed to fiscal constraints, combat system integration challenges, and the technological advancements in other weapon systems, such as directed energy, hypersonic missiles, and electronic warfare systems.
The EMRG technology promised to revolutionize the Navy's artillery systems by launching projectiles at hypersonic speeds using electromagnetic force rather than traditional gunpowder. However, the technology failed to meet the Navy's expected range capabilities, and the cost of its development had exceeded the budget, leading to the decision to cancel the program.
The Navy's Chief of Naval Operations, Adm. John Richardson, had warned Congress as early as 2018 that the EMRG program was facing challenges with its barrel engineering, the materials required to sustain the power pulse, and the heat and pressure involved in launching the projectiles. Despite the Navy's efforts to improve the program's technological capabilities, it was deemed not cost-effective compared to other weapon systems currently under development.
The decision to cancel the EMRG program is part of the Navy's reform initiative to prioritize offensive and defensive capabilities that are more practical, effective, and affordable. The Navy's budget request for the fiscal year 2022 shows that funding for gun-launched guided projectiles had been canceled.
The Navy's decision to halt the EMRG program is a reminder that investing in advanced technology is not always a guarantee of success. In today's rapidly changing world, organizations must carefully evaluate the feasibility, practicality, and affordability of new technology before investing large sums of money and resources. The US Navy's decision to cancel the EMRG program demonstrates that it is essential to strike a balance between innovation and practicality, especially when dealing with limited resources.
Railgun technology in 2023: What's next?
The US Navy invested heavily in researching and developing the technology, but recently announced a shift towards other emerging weapon technologies such as hypersonic missiles and directed energy weapons. In 2023, however, Chinese researchers are taking up the mantle, experimenting with various methods to improve the durability and performance of railguns. Using liquid metal as a cooling material for the rails has proven effective in reducing wear and tear, and recent reports suggest that the Chinese railgun prototype has been a success. It has the ability to launch projectiles at a higher velocity and longer range than the US Navy's version, with one test launching a projectile past Mach 7 to a target 155.3 miles away.
While verified news on the Chinese railgun is limited, it remains to be seen if railguns will be a technological dead-end or if they will eventually become part of standard military equipment. For now, the focus is on seeking alternative and more reliable means of long-range destruction, but with ongoing research, railgun technology may still have breakthroughs in the coming years.