Rocket propelled grenade

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A (RPG) is a hand-held, shoulder-launched anti-tank weapon capable of firing an unguided rocket equipped with an explosive warhead. Most modern main battle tanks (MBTs) are largely immune to unguided anti-tank weapons due to advances in armor design requiring more precise aiming to hit weak spots. RPGs, however, are still used very effectively against light-skinned vehicles such as armored personnel carriers (APCs) or unarmored wheeled vehicles, as well as against buildings and bunkers. They can still be a threat to an MBT under certain tactical conditions (see below).

RPG is the Russian acronym of "Ruchnoy Protivotankovy Granatomyot" (Ручной противотанковый гранатомёт, РПГ) and is translated into English as "handheld antitank grenade-launcher" The commonly used term "rocket-propelled grenade" is a mistranslation, backformed from the acronym RPG and does not follow correct naming conventions used by English speaking militaries to describe these weapons.

Contents

1 Description
2 Warheads
3 Tactics
4 History
5 See also
6 External links

Description

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An RPG is composed of two main parts: the launcher and the 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 U.S. M72 LAW; others are reloadable such as the Soviet RPG-7.

The RPG launcher is a hollow tube that concentrates the rocket exhaust to create an over-pressure within the tube. This over-pressure propels the warhead at a higher speed than from the specific impulse of the rocket alone. This higher speed is necessary for the rocket to be stable in flight. The launcher is also designed so that the rocket burns completely within the tube and exits the launcher without dishcharging an exhaust that would be dangerous to the operator. The high-temperature rocket exhaust is hazardous 15 to 20 metres to the rear of an RPG launcher. The launcher must be cleaned periodically, as built-up residue will result in an excess of over-pressure, causing the sighting mechanism to be driven into the operator's eye when the rocket is fired. Blindness in one eye often results.

All RPGs are similar in concept, however, there are significant differences in their operation. In the RPG-7, the warhead is loaded into the front of the launcher. Pulling the trigger strikes a percussion cap. The cap ignites a solid-fuel rocket. The rocket propels the 85 mm warhead forward without significant recoil. As the warhead emerges from the launcher, fins spring out from the base of the rocket tube, stabilizing the warhead's flight.

According to the US Army Training and Doctrine Command (TRADOC) Bulletin 3u (1977) Soviet RPG-7 Antitank Grenade Launcher -- Capabilities and Countermeasures, the RPG-7 munition has 2 sections: a "booster" section and a "warhead and sustainer motor" section. These must be assembled into the ready-to-use grenade. The booster consists of a "small strip powder charge" that serves to propel the grenade out of the launcher at 117 meters/s. Once the grenade is 10 meters or so from the launcher, the sustainer motor ignites and propels the grenade for the next few seconds, reaching a speed of 294 meters/s. The TRADOC bulletin provides anectdotal commentary that the RPG-7 has been fired from within buildings, which agrees with the two-stage design. It's stated that only a 2-meter standoff to a rear obstruction is needed for use inside rooms or fortifications.

The fins not only provide drag stabilization, but are designed to impart a mild rotation to the grenade. A video of an RPG-7 grenade in flight was shown on one report from Iraq on the American ABC TV network's Nightline program. This included a close-up view of an incoming RPG-7 projectile, wobbling slowly, illustrating the extent of the spin.

Due to the configuration of the RPG-7 sustainer/warhead section, it responds counter-intuitively to crosswinds. A crosswind will tend to exert pressure on the stabilizing fins, causing the projectile to turn into the wind. While the rocket motor is still burning, this will cause the flight path to curve into the wind. The TRADOC bulletin explains aiming difficulties for more distant moving targets in crosswinds at some length, as the RPG-7 optical sight's reticle is somewhat challenging.

An RPG is an inexpensive way to deliver an explosive payload a distance of 100 yards with moderate accuracy. Substantially more expensive shoulder-fired, wire-guided rockets are used when accuracy is important. These rockets trail a thin wire behind them during firing and can be steered by the operator while in flight. In 1982, British troops were sent to the Falklands War armed with a number of wire-guided anti-tank missiles even though there were no Argentinean tanks in the Falklands Islands. The British used these expensive weapons to destroy Argentinean bunkers because they did not have any cheap unguided rockets available. This prompted the U.S. military to field the SMAW, the U.S. equivalent of the RPG.

Warheads

The HE warhead is a general-purpose explosive warhead for use against unarmored targets such as infantry, unarmored wheeled vehicles, and fixed positions. The HE warhead detonates upon impact. The warhead case and charge generate moderate amounts of shrapnel.

The HEAT (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 crushes the metal lining and propels some of it forward at a very high velocity. The resulting narrow jet of metal can punch through Rolled Homogeneous Armor (RHA) used in many armored vehicles including some types of main battle tanks. Although the warhead on RPG systems is too small to penetrate the main armor of most modern battle tanks, it is still capable of secondary damage to vulnerable systems (especially sights, tracks, rear and roof of turrets) and can also penetrate most lightly armored or unarmored vehicles.

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 warhead. Another recent development is a tandem HEAT warhead capable of penetrating reactive armor.[link]

Accuracy limits the standard RPG-7 to a practical range of 50 m, although it can reach 150 or even 300 m in skilled hands. It has an indirect fire (bombardment) range to 920 m, limited by the 4.5 second self-destruct timer.

Tactics

RPGs are a low-cost, low-tech, direct fire man-portable weapon, used primarily to engage thinly-armored and unarmored vehicles and personnel. It also can be used as an anti-aircraft weapon, usually against hovering helicopters. RPGs were used extensively against the Soviet intervention forces in Afghanistan by the Mujahedin and against South Africans in Angola by the UNITA rebels.

Because of the inherent inaccuracy of the RPG, the operator must fire relatively close to the intended target, increasing the chances of being spotted and suppressed. Most modern armies use the ATGM as their primary infantry anti-tank weapon, but the RPG can still be used effectively under certain tactical conditions, especially urban warfare, where they are favored by low-tech armies and terrorist organizations. 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 before moving into his kill zone.

The operator must move after firing the RPG as the ignition of the rocket generates a flash visible to the enemy, and usually leaves a smoke trail leading back to the firing position. In Afghanistan, Mujahideen RPG shooters who remained in position after firing were often killed by Soviet counter-fire.

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. 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 as a screen in hazardous areas.

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. Chechen guerillas also attacked Russian tanks from basements. This was effective because the tanks' guns could not depress far enough to return fire. Both artillery suppression and infantry screens prevented antitank attacks by RPG teams. Russian tank columns were eventually protected by attached mobile antiaircraft artillery used in the ground role to suppress and destroy Chechen ambushes.

South African and Soviet APCs would be targeted as soon as they stopped to let off troops. The South Africans developed a doctrine of driving the APC in widening circles, using automatic gunfire from one side to destroy the RPG teams. This prevented the APCs from becoming stationary targets as they would if they stopped to let off troops.

The RPG is somewhat useful in the anti-aircraft role. Helicopters would typically be ambushed as they landed or hovered. The Mujahedin would modify the RPGs to make them more effective against helicopters. By adding a curved pipe to the rear of the launcher tube to divert exhaust, the RPG can be fired upward at aircraft from a prone position, making the shooter less obvious prior to firing and decreasing the risk of injury from hot exhaust gasses. Again, multiple launchers were needed in order to increase the chances of a hit. Both of the Blackhawk helicopters lost by the U.S. in Mogadishu, Somalia, were downed by RPG-7s. In Afghanistan, Soviet helicopters countered by clearing landing zones (LZs) with antipersonnel saturation fire. They also began arriving with unpredictable numbers of wingmen (two or three), to upset Afghan force estimations and preparation. The Afghans countered by digging prepared firing positions with top cover. The Soviets countered this by using air-dropped fuel-air bombs to clear LZs. The Afghans were able to counter this by using U.S.-supplied Stinger surface-to-air missiles and finally prevailed.

Afghans sometimes used RPG-7s at extreme long range, exploded by their 4.5 second self-destructs, which calculates to an almost 1 km range. This performed expedient indirect antipersonnel bombardment, and sometimes was used to discourage reconnaissance by aircraft.

RPG launchers in Iraq

During the 2003 U.S invasion of Iraq and the subsequent occupation, the RPG has become a favorite weapon of the Iraqi guerillas fighting U.S. troops. Since most readily-available RPG-7 rounds cannot penetrate M1 Abrams tank armor, it is primarily used to attack soft-skinned Humvees in supply convoys and unarmored trucks, and also as an anti-personnel weapon against infantry foot patrols.

History

The most widely distributed and used RPG in the world is the RPG-7, developed by the Soviet Union. The Soviets developed the basic design of the RPG during WW II, imitating and combining important design features of the US Bazooka and the German Panzerfaust.

External links

[M72 LAW]
[RPG-7]
[Countering The RPG Threat]
[Most Valuable Weapon: the RPG], Gary Brecher on the history and use of the RPG
[Nazarian's Gun's Recognition Guide]