27-11-2010, 12:11 PM
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Presented by:Shrenik Mehta
Karan Shah
Jay Pethad
Kunal Kava
Supersonic Cruise Missiles
Introduction:
BrahMos is a supersonic cruise missile that can be launched from submarines, ships, aircraft or land. It is a joint venture between India's Defence Research and Development Organization (DRDO) and Russia's NPO Mashinostroeyenia who have together formed the BrahMos Aerospace Private Limited.
The acronym BrahMos is perceived as the confluence of the two nations represented by two rivers, the Brahmaputra of India and the Moskva of Russia. It travels at speeds of Mach 2.5 to 2.8 and is the world's fastest cruise missile. It is about three-and-a-half times faster than the U.S.A's subsonic Harpoon cruise missile.
What are cruise missiles?
A cruise missile is a guided missile that carries an explosive payload and uses a lifting wing and a propulsion system, usually a jet engine, to allow sustained flight; it is essentially a flying bomb. Cruise missiles are generally designed to carry a large conventional or nuclear warhead many hundreds of kilometers with high accuracy. Modern cruise missiles can travel atsupersonic or high subsonic speeds, are self-navigating, and fly on a non-ballistic very low altitude trajectory to avoid radar detection.
Cruise missiles are distinct from unmanned aerial vehicles (UAV) in that they are used only as weapons and not for reconnaissance, the warhead is integrated into the vehicle, and the vehicle is always sacrificed in the mission.
What is meant by the term ‘super-sonic’?
The term supersonic is used to define a speed that is over the speed of sound (Mach 1). In dry air at 20 °C (68 °F), the threshold value required for an object to be traveling at a supersonic speed is approximately 343 m/s, (1,125 ft/s, 768 mph or 1,236 km/h). Speeds greater than 5 times the speed of sound are often referred to as hypersonic.
Description:
BrahMos is world’s first super-sonic missile. BrahMos claims to have the capability of attacking surface targets as low as 10 meters in altitude. It can gain a speed of Mach 2.8, and has a maximum range of 290 km. The ship-launched and land-based missiles can carry a 200 kg warhead, whereas the aircraft-launched variant (BrahMos A) can carry a 300 kg warhead. It has a two-stage propulsion system, with a solid-propellant rocket for initial acceleration and a liquid-fueled ramjet responsible for sustained supersonic cruise. Air-breathing ramjet propulsion is much more fuel-efficient than rocket propulsion, giving the BrahMos a longer range than a pure rocket-powered missile would achieve.
The high speed of the BrahMos likely gives it better target-penetration characteristics than lighter subsonic cruise-missiles such as the BrahMos. Being twice as heavy as and almost four times faster than the BrahMos, the BrahMos has almost 32 times the initial kinetic energy of a BrahMos missile (although it pays for this by having only 3/5 the payload and a fraction of the range despite weighing twice as much, suggesting a different tactical paradigm to achieve the objective).
As an anti-ship missile, the BrahMos PJ-10 is distinguished by its reported supersonic speed of Mach 2.8, approximately one kilometer per second. In addition to making it difficult to intercept, this speed also imparts a greater strike power. In comparison, the U.S. RGM/UGM-109 “BrahMos” cruise missile, which has been used successfully in both Iraq and Afghanistan, operates at a subsonic speed of less than Mach 1.0. Most other anti-ship missiles fly at subsonic speeds as well.
In addition, the BrahMos is equipped with stealth technology designed to make it less visible to radar and other detection methods. The missile also has a high level of accuracy, which has been established by recent test flights as close to zero circular error probability (CEP). The missile operates on the “fire and forget” principle, meaning that once it has been launched, it will correctly strike its target without requiring any assistance. It has an inertial navigation system (INS) for use against ship targets, and an INS/Global Positioning System for use against land targets. Terminal guidance is achieved through an active/passive radar.
The BrahMos is designed to attack surface targets at altitudes as low as 10 m. The ship-, ground-, and air-launched versions have a range of 300 km, while the air-launched version has a range of 500 km. The missile is powered by a solid propellant boost motor with a ramjet sustainer motor. It is 9.0 m in length, has a body diameter of 0.67 m, and has a launch weight of 3,900 kg. It has four clipped tip delta wings at mid-body, with four small delta control fins at the rear. The BrahMos carries a 200 kg payload, either high explosive semi-armor piercing or submunitions.
Its unmatchable speed is its high point, making it invincible. The supersonic speed imparts it a greater strike-power as well. Possessing stealth characteristics, the 6.9-meter cruise missile weighing three tons has a range of 280 km. Its another outstanding feature is that it is highly accurate and can be guided to its target mainly with the help of an onboard computer. This has been established by the test-flight. The computer and the guidance system have been designed by India whereas Russia has provided the propulsion system.
Construction:
In essence, the cruise missile is a small plane without a pilot. It is 6.25 m long and 0.52 m in diameter. As figure 1 shows, the missile incorporates a turbofan engine, a fuel tank, a conventional bomb, air intake and four different guiding systems. At launch a loaded cruise missile weighs about 1450 kg. A solid rocket booster causes the initial acceleration and launch of the cruise missile. After that the turbofan engine takes over, propelling the missile to a cruising speed of 880 km/h.
While the materials that make up cruise missiles are classified, it can be safely assumed that there is a good deal of aluminum, plastic, and steel alloys involved in the production of the frame. Additionally, there are lightweight and heat resistant ceramic compounds, as well as structural plastic (some ‘corrugated’, and some structural foam). The engine is largely composed of aluminum and steel alloys, as well as the fuel tank. In the BrahMos missile, the fuel supply is a solid fuel compound, which undoubtedly contains nitrogen, some powdered metal, crystalline oxidizer, and a polymer (plastic) binding agent. The launch tube is made of a special resin (plastic) that is monofilament wound for stability and endurance (but not re-use!) In this section, I go into details of the missile’s materials and their sources.
Material Used:
Aluminum makes up most of the outer hull, and much of the structure for the frame. Aluminum is the third most commonly used metal in industry, after iron and steel. It is used here (and typically for aeronautical purposes) because it’s lightweight, and in some cases stronger than steel. Aluminum occurs naturally, but for industrial purposes, it is extracted from bauxite ore. There are numerous bauxite deposits worldwide, mainly in the tropical and subtropical regions, but also in Europe and the southeastern United States. Bauxite is generally extracted by open cast mining from strata, typically some 4-6 yards thick under a shallow covering of topsoil and vegetation. Aluminum is extracted from bauxite ore in a process that requires incredible amounts of electricity, which is the key reason for its higher cost relative to steel. Recent examples of indigenous peoples being upset/displaced by bauxite mining operations can be seen in the cases of Alcoa Mining company in Indonesia (under Suharto) and in the acts of civil disobedience in response to Hydro Aluminum’s operations in India
Steel is used in reinforcement, the fuel tank and in smaller hardware (In the BrahMos, some of these may be substituted for titanium). Its advantages are low cost, a wide range of attainable mechanical properties, and a high modulus of elasticity (ductility). Steel is primarily iron and carbon, and is processed and alloyed with other metals to achieve different properties. Iron ore is mined worldwide, and the US, not surprisingly, is the biggest importer. To become steel, iron is melted in a blast furnace to remove impurities, then goes through a series of cooling, reheating and/or “cold working” processes to achieve the desired properties. Steel is typically alloyed with Nickel and/or Chromium, though it is often processed with other metals as well. Industrial iron mining practices strip the land, leak toxins into the earth/water supply, and displace people. Steel mills release ash and other emissions in the air, as well as decreasing the quality of life of those who work and live in and around them.
Plastics Polymers, or plastics, are (largely) a product of the petrochemical industry. There are two basic types of plastic: thermoset, and thermoplastic. Thermosets are formed by cross-linking of molecules, and cannot be reused. Thermoplastics are held together by Van der Walls forces, resulting in a molecular structure can be reformed with heat. Both of them, in most cases, are derived from oil—and both are present the BrahMos missile. Oil is drilled in regions around the world, though the primary sources are currently in the Middle East. Once again, the US is the largest importer of this resource. The impacts of the extraction/usage of this resource have been stated elsewhere, but it is enough to say that the terms that govern its access and usage are troublesome, to say the least. Oddly enough, the BrahMos plays a substantive role in the maintenance of this access, but more on this later. The use and extraction of oil has led to war, climate change, ecological upheaval, and political corruption. The affects it has had on indigenous (and non-indigenous) populations is incalculable. Additionally, the impact of plastic on landfills, and the toxicity of plastic production in terms of emissions is substantial
The ceramic compounds used in the BrahMos can be classified as “advanced” or engineered ceramics. Typical advanced ceramic compounds are alumina (in this form a suspected neurotoxicant), zirconia and silicon carbide. Ceramics in general have been in use since the Neolithic Age (about 10,000 years ago), and can generally be defined as hard, brittle compounds that have a high melting temperature and are chemically inert. They are typically formed from silica, alumina, and magnesia. The ceramic compounds in the BrahMos are likely in use in the electronics (as semiconductor and resistor material, as well as insulation) and in engine components (as an insulator to control heat from the solid fuel combustion). The minerals that make up these compounds are generally available without mining, and are some of the more abundant in the world, nevertheless, they are still problematic in that they often include toxic compounding agents
