Rocket-propelled grenade

A rocket-propelled grenade (often abbreviated RPG) is a shoulder-fired, anti-tank weapon system that fires rockets equipped with an explosive warhead. These warheads are affixed to a rocket motor and stabilized in flight with fins. Some types of RPG are reloadable, while others are single-use. RPGs, with the exception of self-contained versions, are loaded from the muzzle. RPGs with HEAT warheads are very effective against armored vehicles such as armored personnel carriers (APCs).

Etymology of "RPG"
RPG is an initialism from the Russian language РПГ or ручной противотанковый гранатомёт (transliterated as "ruchnoy protivotankovy granatomyot"), meaning "hand-held anti-tank grenade launcher". Thus, "rocket-propelled grenade" is an acronym.

There were Soviet weapons preceding the rocket-propelled grenade that were also designated with the "RPG" acronym (RPG-40, RPG-43 and RPG-6) but those were anti-tank hand grenades, and the acronym stood for ручная противотанковая граната, or "hand-held anti-tank grenade", they were not launchers. The projectile of RPG launchers is similarly designated PG, (PG-7, etc.), which similarly stands for противотанковая граната, "anti-tank grenade".

History
The RPG has its roots in the 20th century with the early development of the explosive shaped charge. The development of practical rocketry provided a means of delivering such an explosive. Research occasioned by World War II produced such weapons as the American bazooka and German Panzerfaust, which combined portability with effectiveness against armored vehicles such as tanks.

The Soviet Union-developed RPG-7 is the most widely distributed, recognizable and used RPG in the world. The basic design of this RPG was developed by the Soviets shortly after World War II in the form of the RPG-2, which is similar in function to the bazooka and the Panzerfaust.

An early method of disabling shaped charges developed during World War II was to apply thin skirt armor or meshwire at a distance around the hull and turret of the tank. The skirt or mesh armor (cage armor) triggers the RPG on contact and much of the molten jet that a shaped charge produces dissipates before coming into contact with the main armor of the vehicle. Well-sloped armor also gives some protection because the shaped charge is forced to penetrate a greater amount of armor due to the oblique angle. The benefits of cage armor are still considered great in modern battlefields in the Middle East, and although similar effects can be obtained using spaced armor, either as a part of the original design or as appliqué armor fitted later, cage armor is preferable due to its low weight and ease of repair.

Today, technologically advanced armies have implemented composite armors such as Chobham armor, which provide superior protection to steel. For added protection, vehicles may be retrofitted with reactive armor; on impact, reactive tiles explode or deform, disrupting the normal function of the shaped charge. Russian and Israeli vehicles also use active protection systems like Drozd, Arena APS or Trophy. Such a system detects and shoots down incoming projectiles before they reach the vehicle.

As in all arms races, these developments in armor countermeasures have led to the development of RPG rounds designed specifically to defeat them, with methods such as a tandem-charge warhead, which has two shaped charges, of which the first is meant to activate any reactive armor, and the second to penetrate the vehicle.

Description
An RPG comprises two main parts: the launcher and a rocket equipped with a warhead. The most common types of warheads are high explosive (HE) or high explosive anti-tank (HEAT) rounds. These warheads are affixed to a rocket motor and stabilized in flight with fins. Some types of RPGs are single-use disposable units similar to the RPG-22; others are re-loadable, such as the Soviet RPG-7.

The launcher is designed such that the rocket exits the launcher without discharging an exhaust that would be dangerous to the operator. In the case of the RPG-7, the rocket is launched by a gunpowder booster charge, and the rocket motor ignites only after 10 metres. In some other designs, the propellant charge burns completely within the tube.

An RPG is an inexpensive way to deliver an explosive payload over a distance with moderate accuracy. Substantially more expensive, wire-guided rockets are used when accuracy is important; these rockets trail a thin wire behind them during firing and steering corrections can be sent by the operator (see Missile guidance) while in flight, such as in the AT-3 Sagger.

Warheads
The HE (high explosive) warhead is a general-purpose explosive warhead for use against soft targets such as infantry, unarmored vehicles and fixed positions. The HE warhead detonates on impact or when the fuse runs out; usually the fuse is set to the maximum burn of the rocket motor but it can be shortened for improvised anti aircraft purposes. The warhead case and charge generate a moderate amount of fragmentation, which can pass through many obstacles without stopping.

The HEAT (high explosive anti-tank) round is a standard shaped charge warhead, similar in concept to those used in tank cannon rounds. In this type of warhead, the shape of the explosive material within the warhead focuses the explosive energy on a copper (or similar metal) lining. This heats the metal lining and propels some of it forward at a very high velocity in a highly plastic state. The resulting narrow jet of metal can defeat armor several hundred milimeters of RHA equivalent, such as that used in light and medium armored vehicles. However, heavily armored vehicles such as main battle tanks are generally too well armored to be penetrated by an RPG, unless weaker sections of the armor are exploited. Various warheads are also capable of causing secondary damage to vulnerable systems (especially sights, tracks, rear and roof of turrets) and other soft targets.

Specialized warheads are available for illumination, smoke, tear gas, and white phosphorus. Russia, China, and many former Warsaw Pact nations have also developed a fuel-air explosive (thermobaric) warhead. Another recent development is a tandem HEAT warhead capable of penetrating reactive armor.

So-called PRIGs (Propelled Recoilless Improvised Grenade) were improvised warheads used by the Provisional IRA.

Effectiveness
The RPG-29 uses a tandem-charge high explosive anti-tank warhead to penetrate explosive reactive armor (ERA) as well as composite armor behind it. It is capable of penetrating MBTs such as the M1 Abrams, older model Mark II version of the Merkava, Challenger 2, or T-90.

In August 2006 in al-Amarah, a Soviet RPG-29 damaged the front underside of a Challenger 2, detonating ERA in the area of the driver's cabin. The driver lost part of his foot and two more of the crew were also injured but the driver was able to reverse 1.5 mi (2.4 km) to an aid post. The incident was not made public until May 2007, and in response to accusations, the MoD said "We have never claimed that the Challenger 2 is impenetrable." Since then, the ERA has been replaced with a Dorchester block and the steel underbelly lined with armour, as part of the 'Streetfighter' upgrade, which was a direct response to this incident. In May 2008, The New York Times disclosed that an American M1 tank had also been damaged by an RPG-29 in Iraq. The American army is ranking the RPG-29 threat to American armor as high; they have refused to allow the newly formed Iraqi army to buy it, fearing it will fall into the insurgent hands.

Various armies and manufacturers have developed add-on tank armor and other systems for urban combat, such as the Tank Urban Survival Kit (TUSK) for M1 Abrams, slat armor for the Stryker, ERA kit for the FV432, AZUR for Leclerc, and others. Similar solutions are active protection systems, engaging closing projectiles such as the Russian Drozd and Arena, as well as the recent Israeli Trophy system.

The RPG-30 was designed to address the threat of active protection systems on tanks by using a false target to trick the APS.

Tactics
RPGs were used extensively during the Vietnam War (by the Vietnam People's Army and Vietcong), Soviet invasion of Afghanistan by the Mujahideen and against South Africans in Angola and Namibia (formerly South West Africa) by SWAPO guerillas during what the South Africans called the South African Border War. Twenty years later, they are still being used widely in recent conflict areas such as Chechnya, Iraq, and Sri Lanka.

One of the first instances when it was used by militants was on 13 January 1975 at the Orly airport in France, when Carlos the Jackal, together with another member from the PFLP, used two Soviet RPG-7 grenades to attack an Israeli El Al airliner. Both missed, and one of them hit a DC-9 of Yugoslav Airlines instead.

RPGs can also be used to achieve a mobility kill, because no matter how thick the tank's armor is, its tracks remain the weakest components. Once a tank has been immobilized, if the tank crew cannot provide covering fire (e.g., from a .50 cal machine gun), the tank may be destroyed easily as it unable to move to protect itself. However, if the tank is recovered and towed out of the battle zone, the tank can easily be repaired and ready for action.

Due to the lack of a guidance system in the RPG rockets, the operator must fire relatively close to the intended target, increasing the chances of being spotted. Most modern armies deploy anti tank guided missiles (ATGM) as their primary infantry anti-tank weapon, but the RPG still remains a potent threat to armored vehicles, especially in situations such as urban warfare or jungle warfare, where they are favored by guerrillas. They are most effective when used in restricted terrain as the availability of cover and concealment can make it difficult for the intended target to spot the RPG operator. Note that this concealment is often preferably outdoors, because firing an RPG within an enclosed area may create a dangerous backblast.

When deployed against personnel, the warhead can be aimed at a solid surface to detonate; popular choices being trees or buildings. Another option is an indirect method of firing the warhead over the intended target area at ranges of 800–1000 m where the warhead would detonate automatically. More skilled shooters can use the RPG self-destruct feature to make it explode over the enemy at closer range. When used in this fashion, the RPG is being used almost like an artillery weapon.

Although they can be—and often are—used against hovering helicopters, they should not be confused with anti-aircraft shoulder fired surface-to-air missile (MANPADS) systems such as the Stinger or SA-7 Grail/SA-14. MANPADS are capable of actively tracking the target as opposed to flying in a ballistic trajectory as the unguided RPG-missiles do; allowing kills at high altitude (which are too far to be hit by an unguided projectile). Furthermore, firing at steep angles poses a danger to the user, because the backblast from firing reflects off the ground. In Somalia, militia members sometimes welded a steel plate in the exhaust end of an RPG's tube to deflect pressure away from the shooter when shooting up at US helicopters. RPGs are used in this role only when more effective weapons are not available.

Afghanistan
In Afghanistan, Mujahideen guerrillas used RPG-7s to destroy Soviet vehicles. To assure a kill, two to four RPG shooters would be assigned to each vehicle. Each armor-vehicle hunter-killer teams can have as many as 15 RPG. In areas where vehicles were confined to a single path (a mountain road, swamps, snow, urban areas), RPG teams trapped convoys by destroying the first and last vehicles in line, preventing movement of the other vehicles. This tactic was especially effective in cities. Convoys learned to avoid approaches with overhangs and to send infantrymen forward in hazardous areas to detect the RPG teams.

Multiple shooters were also effective against heavy tanks with reactive armor: The first shot would be against the driver's viewing prisms. Following shots would be in pairs, one to set off the reactive armor, the second to penetrate the tank's armor. Favored weak spots were the top and rear of the turret.,

Afghans sometimes used RPG-7s at extreme range, exploded by their 4.5-second self-destruct timer, which translates to roughly 950m flight distance, as a method of long distance approach denial for infantry and reconnaissance.

Angola
During the South African Border War, the Soviet RPGs used by SWAPO guerilllas and their Angolan supporters posed a serious threat to South Africa's lightly armored APCs, which could be easily targeted as soon as they stopped to disembark troops. In response to such ambushes, police and military units, such as the infamous Koevoet, used the Cantabrian circle tactic of driving their vehicles in widening circles, using automatic weapons fire from one side to destroy the RPG teams. By staying on the move and refusing to halt as normal, the APCs were difficult to target. This peculiar tactic was developed informally in the field and passed on to new personnel as it demanded precise coordination skills from everyone involved.

Chechnya
During the First (1994–1996) and Second Chechen Wars (1999–2009), Chechen rebels used RPGs to attack Russian tanks from basements and high rooftops. This tactic was effective because tank main guns could not be depressed or raised far enough to return fire, in addition, armor on the very top and bottom of tanks is usually the weakest. Russian forces had to rely on artillery suppression, good crew gunners and infantry screens to prevent such attacks. Tank columns were eventually protected by attached self-propelled anti-aircraft guns (ZSU-23-4, Tunguska-M1) used in the ground role to suppress and destroy Chechen ambushes.

Chechen fighters formed independent "cells" that worked together to destroy a specific Russian armored target. Each cell contained small arms and some form of RPG (RPG-7V or RPG-18, for example). The small arms were used to button the tank up and keep any infantry occupied, while the RPG gunner struck at the tank. While doing so, other teams would attempt to fire at the target in order to overwhelm the Russians' ability to effectively counter the attack. To further increase the chance of success, the teams took up positions at different elevations where possible. Firing from the third and higher floors allowed good shots at the weakest armor (the top). When the Russians began moving in tanks fitted with explosive reactive armor (ERA), the Chechens had to adapt their tactics, because the RPGs they had access to were unlikely to result in the destruction of the tank.

Iraq
In the period following the 2003 invasion of Iraq, the RPG became a favorite weapon of the insurgent forces fighting U.S. troops. Since most of the readily-available RPG-7 rounds cannot penetrate M1 Abrams tank armor from the front, it is primarily effective against soft-skinned or lightly armored vehicles, and infantry. Even if the RPG hit does not completely disable the tank or kill the crew, it can still damage external equipment, lowering the tank's effectiveness or forcing the crew to abandon and destroy it.

Newer RPG-7 rounds are more capable, and in August 2006, an RPG-29 round penetrated the frontal ERA of a Challenger 2 tank during an engagement in al-Amarah, Iraq, and wounded several crew members.

Northern Ireland
The RPG-7 has been used during The Troubles by both the Provisional Irish Republican Army, the Ulster Volunteer Force, and other Republican and Loyalist paramilitaries. The RPG-7 has been used on British armoured personal carriers and static observation points throughout the conflict, especially in Republican West Belfast and South Armagh.

El Salvador
RPGs were a main tool used by the FMLN's guerrilla forces in the Salvadoran Civil War. For example, during the June 19, 1986 overrun of the San Miguel Army base, FMLN sappers dressed only in black shorts, their faces blacked out with grease, sneaked through barbed wire at night, avoiding the searchlights, they made it to within firing range of the outer wall. Using RPGs to initiate the attack, they blew through the wall and killed a number of Salvadorean soldiers. They eliminated the outermost sentries and searchlights with the rockets, then made it into the inner wall, which they also punched through. They were then able to create mayhem as their comrades attacked from the outside.

Yugoslavia
During the Yugoslav Wars (1991-1995), RPGs were used by all sides with great effect. RPGs used were M-79 Osa{Wasp}, RPG-7, RB M-57 and M-64 'Zolja'. RPGs were used with great effect in the famous Battle of Vukovar by the Croatian army, during which more than 300 tanks, APCs and vehicles were put out of action by the defenders.

Anti-aircraft
Using RPGs as improvised anti aircraft batteries has proved successful in Somalia, Afghanistan and Chechnya. Helicopters are typically ambushed as they land, take off or hover.

In Afghanistan, the Mujahideen often modified RPGs for use against Soviet helicopters by adding a curved pipe to the rear of the launcher tube, which diverted the backblast, allowing the RPG to be fired upward at aircraft from a prone position. This made the operator less visible prior to firing and decreased the risk of injury from hot exhaust gases. Mujahideen also utilised the 4.5-second timer on RPG rounds to make the weapon function as part of a flak battery, using multiple launchers to increase hit probabilities. At the time, Soviet helicopters countered the threat from RPGs at landing zones by first clearing them with anti-personnel saturation fire. The Soviets also varied the number of accompanying helicopters (two or three) in an effort to upset Afghan force estimations and preparation. In response, the Mujahideen prepared dug-in firing positions with top cover, and again, Soviet forces altered their tactics by using air-dropped fuel-air bombs on such landing zones. As the U.S.-supplied Stinger surface-to-air missiles became available to them, the Afghans abandoned RPG attacks as the smart missiles proved especially efficient in the destruction of unarmed Soviet transport helicopters, such as Mil Mi-17.

In Somalia, both of the UH-60 Black Hawk helicopters lost by U.S. forces during the Battle of Mogadishu in 1993 were downed by RPG-7s.

Russian RPGs
RPGs currently in service in the Russian Ground Forces:
 * Anti-personnel explosives
 * RPG-7V2: Reloadable RPG launcher, TBG-7V thermobaric rocket and OG-7V fragmentation grenade
 * RPG-27 "Tavolga": One-shot disposable RPG launcher, RShG-1 thermobaric rockets
 * RPG-29 "Vampir": Reloadable RPG launcher, TBG-29 thermobaric rockets
 * Anti-tank explosives'''
 * RPG-7V2: Reloadable RPG launcher, PG-7VL with ~500 mm RHA penetration, PG-7VR with ~600 mm RHA penetration after ERA
 * RPG-16: Reloadable RPG launcher, PG-16 with ~300 mm RHA penetration, higher accuracy and four times the range of the RPG-7
 * RPG-18 "Muha (Fly)": One-shot disposable RPG launcher, PG-18 with ~375 mm RHA penetration
 * RPG-22 "Netto (Nett)": One-shot disposable RPG launcher, PG-22 with ~400 mm RHA penetration
 * RPG-26 "Aglen": One-shot disposable RPG launcher, PG-26 with ~500 mm RHA penetration
 * RPG-27 "Tavolga": One-shot disposable RPG launcher, PG-27 with ~750 mm RHA penetration after ERA
 * RPG-28: One-shot disposable RPG launcher, with ~1000 mm RHA penetration after ERA
 * RPG-29 "Vampir": Reloadable RPG launcher, PG-29V with ~750 mm RHA penetration after ERA
 * RPG-30 One-shot disposable RPG launcher, with a 'precursor' forerunner additional sub-munition, intended to defeat Active Defense Systems like Trophy
 * RPG-32 "Hashim": Latest variant of RPG 105 mm Caliber, PG-32V with ~650 mm RHA penetration