There can be no reconciliation where there is no open warfare. There must be a battle, a brave boisterous battle, with pennants waving and cannons roaring, before there can be peaceful treaties and enthusiastic shaking of hands.
War does not determine who is right; War determines who is left.
Interests:Eliminating all those who will oppose me and caring for those who will follow me by giving them the spoils of war. Bwa-Ha-Ha-Ha-Ha! Expertise:Leading a band of fighting men to World Conquest, slowly but surely...Bwa-HA-HA-HA-HA-HA!
Now, where were we? Occupation:Military Industry:Other
They house 6,000 crew members and 70 to 80 aircraft.
They are constructed of about 1 billion individual pieces.
What this means is that an aircraft carrier is worth between $4 billion and $5 billion -- it is a substantial investment by itself. Plus, it is carrying a small town's worth of people as well as a billion dollars in aircraft.
Photo courtesy Department of Defense - Defense Visual Information Center Nimitz battle group -- USS Nimitz aircraft carrier, guided-missile cruiser USS Port Royal, and nuclear-powered submarine USS Annapolis -- in the North Persian Gulf during Operation Southern Watch
In other words, an aircraft carrier is extremely valuable. And without protection, an aircraft carrier is extremely vulnerable. That's why aircraft carriers never leave home alone. They are always escorted by an extensive flotilla of other ships. The aircraft carrier plus the flotilla is known as the carrier battle group. A modern carrier battle group is nearly invincible. In this article, you will learn about these powerful collections of military force and see why they have become so important to U.S. naval operations.
The Carrier
An aircraft carrier allows the U.S. navy to move an entire airport, along with 70 to 80 fighters, bombers and support aircraft, anywhere in the world where there is an ocean. This ability gives the United States incredible flexibility, because there is no need for treaties or permission from other nations. With a speed of approximately 700 nautical miles per day and bases on both the east coast of the United States and in Hawaii, aircraft carriers can arrive anywhere in the world in less than two weeks.
Photo courtesy Department of Defense - Defense Visual Information Center Left: Nuclear-powered aircraft carrier USS Enterprise Right: USS Sacramento support ship, USS Reid frigate
Because aircraft carriers are so valuable, because they are so powerful and because they are so few in number (the U.S. has only 12 of them, with two under construction [ref]), they are very obvious targets for enemy forces. Aircraft carriers are also huge and impossible to hide. They are vulnerable from several different angles:
The enemy can attack from the sea with boats equipped with long-range cannons and cruise missiles.
The enemy can attack from underwater with submarines, mines and torpedoes.
The enemy can attack from the air with airplanes, bombs and missiles.
The carrier battle group is responsible, therefore, for protecting the aircraft carrier at the center of the group.
The Carrier Battle Group
The U.S. Navy forms carrier battle groups on an as-needed basis and assigns ships to the group based on the mission. Therefore, no two carrier battle groups are the same. However, a typical carrier battle group consists of the following ships:
The aircraft carrier itself
Photo courtesy Department of Defense - Defense Visual Information Center Aircraft carrier USS Kitty Hawk launching a radar-guided, air-to-air missile during a live-fire exercise
Two guided-missile cruisers These are offensive ships loaded with cruise missiles to strike land targets
Two destroyers Destroyers traditionally are defensive ships. They can defend against attacks by submarines and aircraft (Wikipedia: Destroyer provides a very nice description of the evolution of destroyers). Destroyers now also come equipped with the ability to launch cruise missiles.
Photo courtesy Department of Defense - Defense Visual Information Center Guided-missile destroyer USS Winton S. Churchill launching a Tomahawk Missile during Operation Iraqi Freedom
One frigate The frigate is used for anti-submarine defense.
Photo courtesy Department of Defense - Defense Visual Information Center Guided-missile frigate USS Talbot launching a target drone during a training exercise off the coast of Chile
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Photo courtesy Department of Defense - Defense Visual Information Center Guided-missile frigate USS Kauffman in Souda Bay, Crete, Greece, during Operation Enduring Freedom
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Photo courtesy Department of Defense - Defense Visual Information Center Guided-missile frigate USS Klakring on its way to the Pacific Phase of Exercise Unitas 43-02 (click here for information about Exercise Unitas)
Two submarines The submarines are defensive ships that can attack enemy ships and submarines.
A supply ship The supply ship carries fuel, food and ammunition for the group.
There may be other ships that travel with the group. For example, there may be troop ships, amphibious ships for the marines, cargo ships carrying tanks and other equipment, mine sweepers, etc. It all depends on the mission.
Photo courtesy Department of Defense - Defense Visual Information Center Aerial view of guided-missile destroyer USS MacDonough and nuclear-powered submarine USS Scamp traveling through the Panama Canal during a training exercise
The Carrier Battle Group in Action
When a carrier battle group arrives at its destination, the 10 or so ships deploy and begin operations. There are approximately 80 aircraft available, and perhaps 8,000 men and women at work. There are two goals:
Accomplish the assigned mission
Defend the battle group against any type of enemy attack
The defensive role is an around-the-clock operation. In times of peace, carrier battle groups are on station around the world and must be constantly vigilant against attack.
A carrier air wing typically consists of nine squadrons, with 70 to 80 total aircraft. The more notable aircraft include:
The F/A-18 Hornet - A single-seat strike fighter jet designed to take out enemy aircraft as well as ground targets
The F-14 Tomcat - A two-seat fighter jet optimized for air superiority (A carrier's F-14 squadron is a crucial weapon in protecting the carrier battle group.)
Photo courtesy Department of Defense - Defense Visual Information Center Flight deck personnel aboard the USS Kitty Hawk aircraft carrier preparing to launch an F-14 Tomcat
The E-2C Hawkeye - A tactical warning and control system aircraft (The aircraft's advanced radar system lets the air wing keep the fighter jets updated on enemy activity.)
To provide a defensive view of the area, the destroyers have powerful radar systems that look upward to search for incoming aircraft. The E-2C Hawkeye aircraft launched from the carrier fly overhead and use their radar to look downward, letting them see low-flying aircraft and ships that may be approaching from over the horizon. The destroyers and frigate use sonar and magnetic sensors to look for submarines approaching from underwater. The goal is to create a sealed bubble around the carrier, with nothing able to enter the bubble without approval.
To learn more about carrier battle groups, aircraft carriers and related topics, check out the links below.
Impact grenades work like a bomb launched from an airplane -- they explode as soon as they hit their target. Typically, soldiers don't throw impact grenades as they would a time-delay grenade. Instead, they use a grenade launcher to hurl the grenade at high speed.
U.S. ground forces typically use grenade launchers that attach to assault rifles. In one conventional gun-mounted launcher design, grenades are propelled by the gas pressure generated by firing a a blank cartridge. Some launcher grenades have their own built-in primer and propellant.
Photo courtesy U.S. Department of Defense A soldier prepares to fire an M-203 grenade launcher mounted to an M-16 assault rifle. U.S. forces typically use rifle-attached grenade launchers like this one.
Afghan fighters and many other forces around the world use rocket-propelled grenade launchers, once mass produced by the Soviet Union. Like missiles, these grenades have a built-in rocket propulsion system.
Impact grenades must be unarmed until they are actually fired because any accidental contact might set them off. Since they are usually shot from a launcher, they must have an automatic arming system. In some designs, the arming system is triggered by the propellant explosion that drives the grenade out of the launcher. In other designs, the grenade's acceleration or rotation during its flight arms the detonator.
The diagram below shows the elements in a simple impact grenade with a rotation arming mechanism.
The grenade has an aerodynamic design, with a nose, a tail and two flight fins. The impact trigger, at the nose of the grenade, consists of a movable, spring-mounted panel with an attached firing pin facing inward. As in the time-delay grenade, the fuze mechanism has a percussion cap and a detonator explosive that ignites the main explosive. But it does not include a chemical delay element.
Photo courtesy Department of Defense A Kurdish refugee with a Soviet RPG-7 grenade launcher, a common weapon in smaller armies and resistance forces
When the grenade is unarmed, the fuze mechanism is positioned toward the tail end, even though it has a spring pushing it toward the nose. It is held in this position by several spring-mounted, weighted pins. The firing pin is not long enough to reach the percussion cap when the fuze is in this position. If the trigger plate is pressed in accidentally, the pin will slide back and forth in the air, and nothing will happen.
When the grenade is fired it begins to spin (like a well-thrown football). This motion is caused by the shape and position of the fins, as well as spiraled grooves inside the barrel of the grenade launcher.
The spinning motion of the grenade generates a strong centrifugal force that pushes the weighted pins outward. When they move far enough out, the pins release the fuze mechanism, and it springs forward toward the nose of the grenade. When the grenade hits the ground, the nose plate pushes in, driving the firing pin against the percussion cap. The cap explodes, igniting the detonator explosive, which ignites the main explosive.
There are dozens of variations on this idea, some with much more elaborate arming and ignition systems. But the basic principle in most of these weapons is the same.
In the future, grenade mechanisms will continue to evolve. Already, some modern grenades use an electronic fuze system instead of a mechanical or chemical fuze. In time-delay electronic grenades, the fuze consists of a digital clock and an electrically operated firing pin. When the firing button or lever is activated, the electronic system starts a precise timer. At the end of the count, the fuze mechanism releases the firing pin. Since it uses an actual clock instead of a combination of chemicals, this timing system is much more accurate than conventional fuzes.
Some cutting-edge launcher-style grenades also have electronic fuzes and arming systems. The U.S. military is currently developing miniature grenades with electronic position sensors. With advanced grenade launchers, soldiers can program a grenade to explode after it has travelled a certain distance. In this way, a soldier can pinpoint particular targets, even ones behind barriers, with extremely high precision.
To learn more about grenades, including their role in military history, check out the links below.
Grenades have played a part in warfare for hundreds of years. They were originally developed around 1000 AD by the Chinese, just one application of their revolutionary gunpowder technology. Europeans came up with their own versions in the 15th and 16th centuries, with mixed results.
Photo courtesy U.S. Marine Corps, photographer Lain A. Schnaible A U.S. Marine tosses a grenade during training exercises.
The typical design of these early grenades was a hollow metal container filled with gunpowder. Soldiers simply lit a wick and tossed the grenade -- as fast as they could. By the 18th century, these weapons had fallen out of favor: They weren't especially useful in the battle style of the time, and the simple design made them extremely dangerous.
The weapon saw a resurgence in the 20th century with the development of new modes of combat. In the trench warfare of World War I, soldiers could use grenades to take out machine gunners without ever revealing themselves to the enemy. Thanks to mechanical ignition systems that made the weapons relatively practical and safe, grenades took their place as an indispensable element in modern warfare.
In this series of blogs that I stole from this site, we'll look inside some typical grenades to find out what sets them off and see what happens when they explode. We'll also look at those invaluable elements that keep everything from exploding too early.
Grenade Basics
Broadly speaking, a grenade is just a small bomb designed for short-range use. The idea of a bomb is very simple: Combustible material is ignited to produce an explosion -- a rapid expansion of gases that produces strong outward pressure. The essential elements of a grenade, then, are combustible material and an ignition system.
The term grenade comes from the French term for pomegranate. In the 16th century, French soldiers (as well as other European armies) used round, pomegranate-sized bombs containing large grains of gunpowder, which resembled a pomegranate's seeds. The French army established the Grenadiers, troops trained to lob these grenades toward the enemy line.
The name "grenade" was picked up again when the weapon was reintroduced in the early 20th century. Soldiers in World Wars I and II had several other names for the weapons, however, such as pineapples, in reference to their shape and bumpy shells.
There are all sorts of combustible materials used in grenades, and they generate a range of explosion types. Some explosions will spread fire, and others will just release a lot of smoke. Some produce little more than a loud noise and a flash of light. Some release toxic gases.
Ignition systems also vary, but they generally fall into one of two categories: time-delay igniters and impact igniters. The function of both systems is to set off the explosion after the grenade is a good distance away from the thrower. As you might expect, the igniter in an impact grenade is activated by the force of the grenade landing on the ground. With a time-delay grenade, the thrower sets off a fuze, a mechanism that ignites the grenade after a certain amount of time has passed (generally a few seconds).
One very simple impact grenade is a container filled with nitroglycerine or another material that combusts easily when jarred. In this case, the flammable liquid itself is the impact igniter. One simple but effective time-delay grenade is the Molotov cocktail, a bottle of flammable liquid with a rag sticking out of it. The rag acts as a crude fuze -- the thrower lights it and tosses the bottle, hoping the flame won't reach the liquid until the grenade is a safe distance away.
The problem with both of these grenades is they can easily explode before the thrower gets rid of them. Proper grenades used by soldiers and police officers have safer, more sophisticated ignition systems, as we'll see in the following sections.
Time-Delay Grenade
The most common type of grenade on the battlefield is the time-delay fragmentation anti-personnel hand grenade. The primary function of this grenade is to kill or maim nearby enemy troops. To ensure maximum damage, the grenade is designed to launch dozens of small metal fragments in every direction when it explodes.
These sorts of grenades, which played a major role in World War I, World War II, Vietnam and many other 20th century conflicts, are designed to be durable, easy to use and easy to manufacture. The conventional design uses a simple chemical delay mechanism. The diagram below shows a typical configuration of this system, dating back to the first World War.
The outer shell of the grenade, made of serrated cast iron, holds a chemical fuze mechanism, which is surrounded by a reservoir of explosive material. The grenade has a filling hole for pouring in the explosive material.
The firing mechanism is triggered by a spring-loaded striker inside the grenade. Normally, the striker is held in place by the striker lever on top of the grenade, which is held in place by the safety pin. The soldier grips the grenade so the striker lever is pushed up against the body, pulls out the pin and then tosses the grenade. Here's what happens inside once the grenade is released:
Photo courtesy Department of Defense The proper way to throw a hand grenade: Depress the striker lever, pull the pin, hurl the grenade.
With the pin removed, there is nothing holding the lever in position, which means there is nothing holding the spring-loaded striker up. The spring throws the striker down against the percussion cap. The impact ignites the cap, creating a small spark.
The spark ignites a slow-burning material in the fuze. In about four seconds, the delay material burns all the way through.
The end of the delay element is connected to the detonator, a capsule filled with more combustible material. The burning material at the end of the delay ignites the material in the detonator, setting off an explosion inside the grenade.
The explosion ignites the explosive material around the sides of the grenade, creating a much larger explosion that blows the grenade apart.
Pieces of metal from the outer casing fly outward at great speed, imbedding in anybody and anything within range. This sort of grenade may contain additional serrated wire or metal pellets for increased fragmentation damage.
Time-delay grenades are very effective, but they do have some significant disadvantages. One problem is their unpredictability: In some chemical fuzes, the delay time may vary from two to six seconds. But the biggest problem with time-delay grenades is that they give the enemy an opportunity to counterattack. If a soldier doesn't time a grenade toss just right, the enemy may pick it up and throw it back before it explodes.
For this reason, soldiers must use impact grenades in certain situations. An impact grenade explodes wherever it lands, so there is no chance for the enemy to throw it back. In the next blogs, we'll see how this sort of grenade works.
As the technology of camouflage has advanced over the past hundred years, so has the technology of seeing through camouflage. These days, military forces can use thermal imaging to "see" the heat emitted by a person or piece of equipment. Additionally, they may use radar, image enhancement, satellite photography and sophisticated listening devices to detect the enemy.
Photo courtesy United States Military U.S. Marine Corps guns concealed with camouflage netting
To hide from this scanning technology, military forces have to think past visual concealment. In modern warfare, camouflage for equipment and soldiers may be made of material that keeps excess heat from escaping, so their thermal "signature" does not show in thermal imaging. In ships, the major heat source is the engine exhaust. To reduce this thermal emission, some modern ships cool the exhaust by passing it through sea water before it is expelled. Some tanks have a similar cooling system to mask the heat of their exhaust.
To counteract image enhancement -- the amplification of tiny amounts of light (including low-frequency infrared light) -- some armies are developing sophisticated smoke screens. A heavy cloud of smoke blocks the path of light, imparting a sort of invisibility to whatever is behind the smoke screen. According to one report, the United States is working on a smoke screen that would be impenetrable to night vision technologies while still allowing advanced U.S. thermal imagers to function correctly. On a larger scale, the British shipbuilder Vosper Thorneycroft has developed a system that uses a series of water nozzles to produce a constant fog all around a ship, obscuring it from view.
Photo courtesy United States Military U.S. Air Force airmen concealing a shelter in Operation Desert Shield: The airmen's uniforms, as well as the camouflage net, are designed to blend in with the desert environment.
Stealth technology allows militaries to hide equipment from radar. In stealth equipment, the surface of a vehicle is made up of many flat planes, interconnected at odd angles. These planes serve to deflect the radar radio waves so they don't bounce straight back to the radar station, but instead bounce off at an angle and travel in another direction. Equipment may also be coated with a layer of "radar-absorbent" material. When a radio wave hits an object, the electrons in that object are excited to some degree, so the wave has passed on some of its energy. In a good conductor, such as a metal radio antenna, the electrons move very easily, so the radio wave doesn't lose much energy in getting those electrons excited. Radar-absorbent material, on the other hand, is a very poor conductor, so there is greater resistance to moving the electrons. Because of this resistance, the radio wave loses more energy, which is emitted as heat. This reduces the overall reflected radio signal.
Photo courtesy United States Military Military vehicles painted with a desert camouflage design for use in Operation Desert Storm
Decoy technology has also advanced in response to modern detection systems. The U.S. Army and other military forces have developed easily-transported, inflatable dummies that not only resemble tanks and other equipment visually, but also replicate the thermal or radar signature of that equipment. To radar and other long-range scanners, these dummies are virtually indistinguishable from real equipment. A less precise decoy strategy is to flood an area with all sorts of objects that show up on radar, thermal-imaging and listening devices, making it harder for the enemy to focus in on any particular piece of equipment.
As detection and spy equipment continues to advance, military engineers will have to come up with more sophisticated camouflage technologies. One interesting idea that is already in the works is "smart camouflage" -- outer coverings that alter themselves based on computer analysis of changing surroundings. No matter how advanced camouflage gets, the basic strategy will still be the approach used by the first human hunters: Figure out how your enemy sees you, and then mask all of the elements that make you stand out.
In the last section, we saw that camouflage material helps soldiers blend in with their environment so the enemy won't detect them. But in modern warfare, hiding individual soldiers is often of secondary importance. Since World War I, opposing forces have used aircraft to seek each other out from the air. In order to hide equipment and fortifications from these "eyes in the sky," ground forces have to use camouflage on a larger scale.
Photo courtesy United States Military An airman in the U.S. Air Force covers military trucks with camouflage netting.
Since World War II, almost all U.S. military equipment has been colored in dull green and brown colors so it blends in with natural foliage. Additionally, soldiers almost always carry camouflaged netting and chicken wire, which they can throw over military vehicles to conceal them better. Soldiers are also trained to improvise camouflage by gathering natural foliage from an area and covering tanks and other vehicles. Using these means, Allied and Axis forces in World War II camouflaged tanks, jeeps, planes, guns, manufacturing plants and entire army bases.
Photo courtesy United States Military A Republic of Korea Army soldier camouflages his tank with tree branches as part of a battle-simulation exercise.
Camouflaging warships has proved more difficult because they are always floating on a wide background that has a uniform color. In World War I, military forces realized that there was no way to make ships "blend in" with the surroundings, but that there might be a way to make them less susceptible to attack. The dazzle camouflage design, developed in 1917, accomplishes this by obscuring the course of the ship (its direction of travel). The dazzle design resembles a cubist painting, with many colored geometric shapes jumbled together. Like the mottling in camouflage wear, this design makes it difficult to figure out the actual outlines of the ship and distinguish the starboard side from the port side. If submarine or ship crews don't know which way a ship is moving, it is a lot harder for them to accurately aim a torpedo.
Militaries also make extensive use of decoys as a means of camouflage. Unlike traditional camouflage, the purpose of decoys is not to conceal forces and equipment, but to divert the enemy from their locations. In the Battle of Britain, Allied forces set up more than 500 false cities, bases, airfields and shipyards, consisting of flimsy structures that resembled actual buildings and military equipment. These remarkable dummies, built in remote, uninhabited areas, significantly diminished the damage to actual cities and fortifications by causing the Axis forces to waste their time and resources.
Photo courtesy United States Military The HMS Belfast, a British ship that served in World War II, is now a floating museum on the River Thames in London. The ship is painted with a variation on the classic "dazzle" camouflage scheme.
This sort of camouflage is still used today, to good effect. Many modern equipment decoys have advanced pneumatic systems, which give them the movement you would expect to see in real equipment. Traditional camouflage is also used today, but it is not always effective. As we'll see in the next section, modern technology makes it much easier for your enemy to find you, no matter how well you blend in with the colors of your surroundings.
