- For the thrash metal band, see Artillery (band)
Historically, artillery refers to any engine used for the discharge of projectiles during war. The term also describes ground-based troops with the primary function of manning such weapons.
Continental Artillery crew from the American Revolution
Modern artillery is distinguished by its large calibre, firing an explosive shell or rocket, and being of such a size and weight as to require a specialized mount for firing and transport. Weapons covered by this term in the include "tube" artillery such as the howitzer, cannon, mortar, and field gun and "rocket" artillery.
The term "artillery" has traditionally not been used for projectiles with internal guidance systems , even though some artillery units employ surface-to-surface missiles. Recent advances in terminal guidance systems for small munitions has allowed large calibre shells to be fitted with precision guidance fuses, blurring this distinction.
The types of tube artillery are generally distinguished by their ballistic trajectory . Cannons or guns (such as infantry support guns or those on a naval ship) are typically longer-barreled, low-trajectory weapons designed for a direct-fire role. Typically the length of a cannon barrel is greater than 25 times its caliber (inner diameter).
Howitzers are typically shorter- and thinner-barreled. Capable of both high- and low-angle fire, they are most often employed in a close indirect-fire role, operating in defilade. Typically the length of a howitzer barrel is between 15 and 25 times in caliber (inner diameter).
Mortars are smaller, very short-barrel, high-angle weapons capable of only high-trajectory fire at a short-range, compared to the other types. Typically the length of a mortar barrel is less than 15 times its caliber (inner diameter).
Modern field artillery can also be split into two other categories: towed and self-propelled. As the name implies, towed artillery has a prime mover, usually a jeep or truck, to move the piece, crew, and ammunition around. Self-propelled howitzers are permanently mounted on a carriage or vehicle with room for the crew and ammunition and capable of moving independently in order to move quickly from one firing position to another - to both support the fluid nature of modern combat and to avoid 'counter-battery fire'. There are also mortar carrier vehicles, many of which allow the mortar to be removed from the vehicle and be used dismounted, potentially in terrain the vehicle can't get to or in order to avoid immediate detection.
Types of artillery:
- field artillery - mobile weapons used to support armies in the field. Subcategories include:
- infantry support guns - directly support infantry units (mostly obsolete).
- mountain guns - lightweight weapons that can be moved through difficult terrain.
- howitzers - capable of high angle fire.
- gun howitzers - capable of high or low angle fire with a long barrel.
- mortars - lightweight weapons that fire projectiles at an angle of over 45 degrees to the horizontal.
- self-propelled artillery - typically guns, mortars or gun howitzers mounted on a vehicle.
- naval artillery - cannons mounted on warships and used either against other ships or in support of ground forces. The crowning achievement of naval artillery was the battleship, but the advent of airpower and missiles have rendered this type of artillery largely obsolete.
- coastal artillery - Fixed-position weapons dedicated to defense of a particular location, usually a coast (e.g. the Atlantic Wall in WW 2) or harbor. Not needing to be mobile, coastal artillery can be much larger than equivalent field artillery pieces, giving them longer range and more destructive power. Since World War II, however, modern weapons and tactics have made them largely obsolete.
- anti-aircraft artillery - weapons, usually mobile, dedicated to attacking aircraft from the ground.
All forms of artillery require a propellant to fire the projectile at the target. A number of different configurations have been developed, each with varying characteristics. They include:
- Tube fired - utilise the pressure of burnt propellant inside a barrel to force a projectile out of the mouth of the barrel.
- Spin stabilised - Use helical grooves or ridges on the inside of the barrel to impart a rotation to the projectile as it is travelling in the barrel.
- Fin stabilised - Use fins at the rear of the projectile in the airflow to maintain correct orientation.
- Inverted tube - Some weapons have been built with the tube built into the projectile and fitted onto a rod fitted to the carriage.
- Recoilless - A tube fired weapon with a breech designed to perforate a bursting disk at firing, and permit a mass of burnt propellant gases with momentum equal to the projectile to exit from the rear of the barrel, to prevent recoil from affecting the weapon.
- Rocket propelled - Tube or rail launched - A reaction propulsion system mounted to the projectile provides continuous thrust for an initial period of the flight.
- Rocket assist - A combination of tube fired and rocket propelled - uses a rocket motor in the base of the projectile to extend the range by about 30%.
- Base bleed - Similar to a rocket assist projectile, uses a small pyrotechnic charge at the base of the projectile. The charge introduces sufficient combustion products into the low-pressure region behind the base of the projectile responsible for a large proportion of the drag to substantially (> 30%) increase range. Like a rocket assist projectile, trajectory is changed to non-ballistic, which may complicate counter-battery location.
High-explosive; shrapnel, canister or anti-personnel; illuminating or star-shell; armour-piercing; incendiary (white phosphorus, "Willie Pete"); gas or aerosol, chemical or biological; smoke; nuclear.
Quick or super-quick; delay; hardened-delay or concrete-piercing; timer; proximity.
Modern artillery operations
Depending on the calibre of the weapons, artillery is used in a variety of roles. Mortars fire relatively short range and small- to medium-calibre (up to about 120 mm) projectiles. Modern mortars, because of their lighter weight and simpler, more transportable design, are usually organic to infantry and armor units, allowing greater responsiveness and negating their shorter range.
Howitzers are generally used in direct support of infantry and armor, where the guns of a battery or even a battalion will be massed to fire simultaneously onto a single point or area target. Howitzers are usually between about 105 mm and 155 mm in calibre.
Attacks aimed at enemy artillery rather than infantry or fortifications are known as counter battery fire.
Radar coupled to computers can accurately track a projectile in flight back to its firing point. This can be used as targeting information for an enemy artillery site.
When artillery fire is directed via radio by a forward observer (FO), the location of FO's transmitter can be calculated and attacked with artillery as well. If successful, this counter-attack will limit the effectiveness of the FO's artillery fire. Radar also improves the all-weather flexibility of modern artillery.
The rise in counter-battery abilities has driven field artillery to adopt "shoot-and-scoot" tactics emphasizing constant maneuver within an designated position area, usually from hide point to firing point and back again. This has required reliance on sometimes temperamental technology and increased the cost of modern field artillery systems.
The field artillery team
Modern field artillery (Post-World War I) has three distinct parts: the forward observer (or FO), the fire direction center (FDC) and the actual guns themselves.
Because artillery is an indirect fire weapon, the forward observer must take up a position where he can observe the target using tools such as binoculars and laser range finders and designators and call back fire missions on his radio. This position can be anywhere from a few thousand meters to 20-30 km distant from the guns.
Using a standardized format, the FO sends either an exact target location or the position relative to his own location or a common map point, a brief target description, a recommended munition to use, and any special instructions such as "danger close" (the warning that friendly troops are within 600 metres of the target, requiring extra precision from the guns). Once firing begins, if the rounds are not accurate the FO will issue instructions to adjust fire and then call "fire for effect."
The FO does not talk to the guns directly - he deals solely with the FDC. The forward observer can also be airborne and in fact one of the original roles of aircraft in the military was airborne artillery spotting.
Typically, there is one FDC for a battery of six guns. The FDC computes firing data, fire direction, for the guns. The process consists of determining the precise target location based on the observer's location if needed, then computing range and direction to the target from the guns' location. These data can be computed manually, using special protractors and slide rules with precomputed firing data. Corrections can be added for conditions such as a difference between target and howitzer altitudes, propellant temperature, atmospheric conditions, and even the curvature and rotation of the Earth. In most cases, some corrections are omitted, sacrificing accuracy for speed. In recent decades, FDCs have become computerized, allowing for much faster and more accurate computation of firing data.
The final piece of the puzzle is the "gun line" itself. The FDC will transmit the fire order to the guns, specifying the number of volleys, a particular shell and fuze combination, the specific charge, a deflection (horizontal direction) and quadrant elevation (vertical direction) both specified in mils, and any special instructions, such as to wait for the observer's command to fire relayed through the FDC. The crews load the howitzers and traverse and elevate the tube to the required point, using either hand cranks (usually on towed guns) or hydraulics (on self-propelled models).
It is actually possible for very modern computer-controlled artillery to fire more than one volley at a target and have all the shells arrive simultaneously, which is called MRSI (Multiple Rounds Simultaneous Impact). This is because there is more than one trajectory for the rounds to fly to any given target - typically one is below 45 degrees from horizontal and the other is above it, and if you can vary the amount of propellant with each shell, you can create more trajectories. Because the higher trajectories cause the shells to arc higher into the air, they take longer to reach the target and so if the shells are fired on these trajectories for the first vollies (starting with the shell with the most propellant and working down) and then after the correct pause more vollies are fired on the lower trajectories, the shells will all arrive at the same time. This is useful because many more shells can land on the target with no warning. With traditional volleys along the same trajectory, anybody at the target point will have a certain amount of time (however long it takes to reload and re-fire the guns) to run away or take cover between volleys. In addition, if guns in more than one location are firing on one target, with careful timing it can be arranged for all their shells to land at the same time for the same reason.
Examples of MRSI guns are South Africa's Denel G6-52 (which can land six rounds simultaneously at targets at least 25 km away) and Germany's Panzer Haubitze 2000 (which can land five rounds simultaneously at targets at least 17 km away). The United States Crusader programme (now cancelled) was slated to have MRSI capability.
When an effect similar to that of MRSI is achieved using separate batteries of traditional artillery, using varying fuses to account for the variant distances or trajectories to cause all shells to detonate on the target at the same time, it is called TOT (Time On Target). The logic behind this practice is the same as that for MRSI: to surprise the enemy and to sow confusion when guns heard to be firing at different times nonetheless result in deadly explosions in the same instant.
An additional wrinkle can be added when some or all of the shells are set for airburst, meaning they explode in the air above the target instead of upon impact. This is a very effective tactic against infantry and light vehicles because it scatters the shrapnel over a larger area and prevents the blast shockwave from being blocked by terrain elements, but usually proves ineffective against troops or equipment protected by even rudimentary fortifications. However, airbursts are probably more likely to impact units protected by trenches and revetments, since the shrapnel can enter them from above, while a ground-burst nearby would simply cause the shrapnel to impact the walls or fly overhead.
The word as used in the current context originated in the Middle Ages. It comes from the Old French atellier meaning "to arrange", and attillement meaning "equipment". From the 13th century an artillier referred to a builder of any war equipment, and for the next 250 years the sense of the word "artillery" covered all forms of military weapons.
Older engines like the catapult, onager, trebuchet and ballista are artillery, but the modern term really dates from the mid 15th century with bombards and then cannon.
Bombards are the earliest of gunpowder artillery, distinguished by their lack of a field carriage, immobility once emplaced, highly individual design, and noted unreliability. The use of the word cannon marks the introduction of a dedicated field carriage with axle, trail and horse-drawn limber - this produced mobile field pieces that could move and support an army in action rather than being found only in siege and static defences. Cannon were always muzzle-loaders, casting technology having standardised and removed the often dangerous breech-loading design.
Cannon operation was still a complex technical task, often undertaken at high-speed and in stressful conditions, where a mistake could easily be lethal. The field carriage eased movement in general, but traverse and elevation were still very limited and slow - the crew ramming levers, handspikes, to force a movement of a few degrees. Larger movements were by brute force shoves of the entire unit, as was repositioning after recoil, an extremely enervating task.
The combining of shot and powder into a single unit, a cartridge, occurred in the 1620s with a simple fabric bag, and was quickly adopted by all nations. It speeded loading and made it safer, but unexpelled bag fragments were an additional fouling in the gun barrel and a new tool - a worm - was introduced to remove them. Shells, explosive-filled fused projectiles, were also developed - problems with the fuses were extremely common.
The development of specialised pieces - shipboard artillery, howitzers and mortars - was also begun in this period. More esoteric designs, like the multi-barrel ribaudequin , were also built.
Oddly the development of cannon almost halted until the 19th-century, improvements in metallurgy, chemistry, manufacturing, and so on, did not alter the basic design and operation of a cannon. From the 1860s artillery was forced into a series of rapid technological and operational changes, accelerating through the 1870s and on. The main impetus was the improvements in small arms, which certainly had not spent 200 years in the doldrums. Artillery could no longer be deployed in the battle line, the large crews and stocks of ammunition were vulnerable to rifle fire, but had to either become smaller, lighter, more mobile and stay with the troops or get much further away. The second type, using indirect fire, forced the development of the technologies and doctrines that produced modern artillery.
technical - metal, propellant, recuperation, manufacturing - obturation, etc.
doctrine - direct vs indirect fire, predicted fire, observed fire - forward observation, pre-planned fire - registered fire, barrage, creeping barrage, STOP (simultaneous time on top)
- I do not have to tell you who won the war. You know, the artillery did. - Gen George S. Patton
- "Our artillery... The Germans feared it almost more than anything we had." - Ernie Pyle "Brave Men", AD 1944
- Artillery is the god of war. - Stalin
- "Contrary to popular belief, we at artillery command do not believe we're God. We merely borrowed his "Smite" button." - Anonymous
- The Mission of the Artillery is to give some class to what would otherwise be merely a vulgar brawl. - Some Redleg.