Hand grenade
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- For the alcoholic beverage sold in New Orleans, see hand grenade (drink).
A hand grenade is a hand-held bomb designed to be thrown by hand. The word "grenade" is derived from the Spanish granada ("pomegranate"), in reference to the general size of early grenades, and because its shrapnel pellets reminded soldiers of the seeds of this fruit. Grenadiers were originally soldiers who specialized in throwing grenades.
Not all grenades are thrown by hand. Several types are fired from rifles or purpose-designed grenade launchers. For example, tear gas grenades used in riot control are fired from riot guns, and the M203 is a grenade launcher that can be fitted to several types of rifles.
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History
The origin of the hand grenade is not a cohesive history, but rather involves the use of lightly ported, approximately fist-sized containers filled with noxious, explosive, or flammable substance, and designed to be thrown to release the held substance on impact with destructive effect.
Archaic grenades were usually made of paper, ceramics, or primitive glass and could contain any sort of dangerous or unpleasant substance, ranging from botanical or animal toxins, skin irritants, lye, acids, flammable naptha, petroleum and unstable gunpowder, diseased matter, parasite eggs (such as locusts, lice, fleas), or even the teeth of a captured dignitary etched with sacred curses.
The use of word grenade in the English language seems to originate in the English Civil War, where cricket ball-sized iron spheres packed with gunpowder and fitted with slow-burning wicks were first used against the Jacobites in the battles of Killiecrankie and Glen Shiel.1
These grenades were deemed not particularly effective, and they saw little use. In World War I the conditions favoured the grenade and among those developed were the Mills bomb, the first modern fragmentation grenade, became available to British front-line troops. The Mills bomb was an explosive-filled steel canister with a triggering pin and a distinctive deeply notched surface; although this segmentation aided fragmentation effect on explosion, this design feature was simply intended to make it easier to grip. This basic "pin-and-pineapple" design is still used in modern grenades.
Parallel to the Mills bomb and its similar counterparts, the Germans issued the Stielhandgranate, or stick grenade, which featured an explosive charge encased in a metal can and mounted on a wooden shaft for throwing. This simple design continued to evolve throughout the First and Second World Wars, with the Model 24 grenade becoming one of the most easily recognised of all small arms, and synonymous with the German soldier.
The Molotov cocktail, an improvised grenade prepared from a glass bottle filled with gasoline (petrol) ignited by a burning strip of cloth when it burst, was first used by poorly-equipped Finnish Army soldiers against Soviet forces during their 1939 Winter War.
Design and usage
Grenades come in different sizes and shapes, for different purposes, but all have two things in common. First, they are hollow so they can be filled with the explosive or chemical filler. Second, they contain a threaded hole into which a fuse can be screwed or inserted.
A grenade is essentially a small bomb, and works very much like a simple firecracker. A firecracker is made up of a paper body filled with gunpowder and has a small fuse. Once lit, the fuse burns down to the powder and blows the paper body apart.
In modern hand grenades, the fuse is lit by an internal mechanical, electronic, and/or pyrotechnic device rather than an external flame. Most are designed to project shrapnel i.e. sharp pieces of the casing or serrated wire or an incendiary material.
Characteristics
Hand grenades share the following three common characteristics:
- Their employment range is short.
- Their effective casualty radius is small.
- Their delay element permits safe throwing.
Hand grenades have the following main parts:
- Body -- contains filler and, in most grenades, also provides fragmentation.
- Filler -- chemical or explosive substance in the grenade, which determines grenade use and characteristics.
- Fuse assembly -- causes the grenade to function by igniting or detonating the filler.
Using grenades
A classic hand grenade has a handle and a removable safety pin that prevents the handle from coming off. After the pin is removed and the handle subsequently released, the grenade will detonate in approximately three to five seconds, depending on grenade type.
When using a grenade, the objective is to have the grenade land with too little time for the enemy to counter-act (such as throwing it back or finding shelter).
One grasps the grenade, including the handle, in the strong hand. Next, one estimates the time of flight to the enemy and subtracts it from four. Then one pulls the pin out of the grenade, releases the handle, waits the time not needed for flight and throws the grenade at the intended target.
US and other NATO soldiers (with the exception of the US Marines) are trained not to "burn off" or "cook off" grenades in this way because of the danger of it exploding in hand if the soldier is distracted or shot and because grenade timers are generally unreliable and can vary up to about two seconds.
A common mistake is to not to grasp the handle before pulling the pin. In this case, the grenade might explode while one is cooking off.
A basic safety precaution is to always throw a grenade from cover. Therefore, if anything goes wrong, it can be thrown quickly out of the cover.
When a grenade is out of control, meaning when it has left one's hand, one should yell "grenade." When a grenade is dropped into a enclosed space like a tunnel, the dropper should yell "Fire in the hole!" to warn that an explosive is about to detonate. Common U.S. military procedure for the fragmentation grenade, unless stealth is of the essence, is to yell "Frag out!" to indicate that a fragmentation grenade has been dispatched.
Grenades are often used in the field to construct booby-traps. The basic concept is to use some action of the intended target (such as opening a door, or starting an auto) to trigger the grenade. These grenade-based booby-traps are simple to construct in the field using readily available material.
Abandoned booby-traps, however, contribute to the problem of unexploded ordnance. The use of tripwire-triggered grenades (along with Claymores and landmines in general) is banned under the Ottawa Treaty and may be treated as a war crime wherever it is ratified. However, China, the United States and the Russian Federation have not signed, citing self-defence needs.
Design and operation
The sketch to the right shows a cross-section of the grenade and fuse parts for a fragmentation grenade. The basic action is as follows:
- Holding the grenade in the throwing hand, thumb over the safety lever, pull the safety pin (pull force of 10–35 pounds or 45–155 newtons).
- When the grenade is thrown (safety lever released), a spring throws off the safety lever and rotates the striker into the primer.
- The primer contains material like the head of a match. When struck by the striker, it ignites and sets fire to the fuse, or powder train. The fuse burns at a controlled rate, providing a time delay (usually 4–5 seconds). When the flame of the fuse reaches the detonator or igniter, it causes action on the filler.
- A detonator is similar to a small blasting cap. Very sensitive to heat, when the fuse burns into it, it causes the grenade to explode.
- An igniter is a cap that burns rapidly. It sets fire to the filler causing a rapidly expanding gas which bursts the container.
- The fragmentation grenade shown uses a detonator.
Hand grenades are usually designed to make them easy to throw. For example they weigh around 500 g (1 lb) and have a diameter of 100 mm. The average grenade can be thrown about 25 to 35 meters by the average soldier. They use a compound of RDX, composition B or TNT as their explosive.
Classical "pineapple" grenades, such as the Mills bomb, used smokeless powder and cast-iron shells, which (in theory) would fragment along deliberately cast weak points in the shell—although the pattern on the grenade body was actually intended to allow the user to have a firm grip on the grenade. In practice, external grooves in the grenade body turned out to have little or no effect on the size and shape of fragments formed.
Grenades have also been made to release smoke, tear gas ("CS"), and illumination. Special forces use "flash-bang" grenades to disorient people during an entry into a room, without the intent of causing lasting injury.
Some grenade designs were made to be thrown longer distances. The German "potato-masher" grenade had a long wooden handle that extended range by fifty percent. It was detonated by a friction igniter in the head, which was activated by a pull string threaded through the hollow stick, by pulling a little plastic ring attached to a string attached to a friction igniter, time fuse, and detonator designed to explode after delay. It is often incorrectly thought to have an impact fuse, though this was the case with an early (1908) British stick grenade design.
Different types of hand grenades
Fragmentation grenades
The fragmentation grenade is an antipersonnel device that is designed to damage its target with a burst of flying shrapnel. The body is made of hard plastic or steel, and flechettes or notched wire provide the antipersonnel shrapnel fragments. The filler may also consist of small metal balls to penetrate the target. When the word "grenade" is used without qualification, and context does not suggest otherwise, this is the kind of grenade usually meant.
These grenades are usually classed as defensive grenades because the effective casualty radius is greater than the distance it can be thrown.
It is assumed the thrower can operate from cover.
The hand sized Mills bomb with a cast iron casing is an example of a defensive grenade.
All grenades for use against personnel based around a simple explosive device, whether the action is enhanced deliberately with a metal casing or not, can be considered part and parcel with the fragmentation grenade.
Concussion grenades
The concussion or overpressure grenade is an antipersonnel device that is designed to damage its target with explosive power alone. Compared to fragmentation grenades, the explosive filler is usually of a greater weight and volume. Also the body far thinner and designed to fragment as little as possible. The shock waves (overpressure) produced by this grenade when used in enclosed areas are greater than those produced by the fragmentation grenade. It is therefore especially useful in enclosed areas.
These grenades are usually classed as offensive grenades because the effective casualty radius is smaller than the distance it can be thrown.
The hand sized US MK3A2 concussion offensive hand grenade an example of an offensive grenade. A more famous is example is the German M24 'Stick Grenade' with a standard tin body.
The term concussion is often applied to stun grenades. This is incorrect. The term concussion arises from the fact the grenade relies on its explosive power and not any other effects.
Smoke grenades
Smoke grenades are canister-type grenades used as ground-to-ground or ground-to-air signaling devices, target or landing zone marking devices, or a screening devices for unit movements. The body consists of a sheet steel cylinder with a few emission holes on top and at the bottom to allow smoke release when the grenade is ignited. The filler consists of 250 to 350 grams of colored (red, green, yellow or violet) smoke mixture (mostly potassium chlorate, lactose and a dye). Another type of smoke grenades are the bursting kind. These are filled with white phosphorus (WP), which is spread by explosive action. White phosphorus catches fire in the presence of air, and burns with a brilliant yellow flame, while producing copious amounts of white smoke (phosphorus pentoxide). These double as incendiary grenades (q.v.).
Smoke grenades are sometimes used in paintball, though these are not necessarily of military grade.
Riot control
Gas grenades designed to disperse large groups of people. Best known is the common teargas grenade. This grenade is similar to the smoke grenade in terms of shape and use. However, in teargas grenades, the filler consists of 80 to 120 grams of CS gas (chlorobenzylidene malononitrile). This toxic chemical causes an extreme burning sensation in the eyes and—when inhaled—in the throat. If the gas stays in the contact with someone for longer than 10 minutes it can cause burning blisters on the skin and irreversible damage to the lungs (for example lung cancer). CS gas can even be fatal to weak and older people. Also, if CS gas is exposed to high temperatures it will release cyanide. (See also the Branch Davidian siege and riot control agents.)
Incendiary grenades
These kind of grenades produce heat by means of a chemical reaction. The body is practically the same as smoke and gas grenades. The filler consists mostly of 600 to 800 grams thermate (TH3), which is an improved version of thermite, the incendiary agent used in hand grenades during World War II. A portion of the thermate mixture is converted to molten iron, which burns at 2200 degrees Celsius (4000 degrees Fahrenheit). It will fuse together the metallic parts of any object that it contacts. The thermate filler of the AN-M14 grenade burns for 40 seconds and can burn through a 1/2-inch (13 mm) homogeneous steel plate. It does not need an external oxygen source and can burn underwater. White phosphorus (also used in smoke grenades) also has a potent incendiary effect, burning at a temperature of 2800°C (5000°F).
Thermate and phosphorus cause some of the worst and most painful burn injuries because they combust so quickly and at such a high temperature. A single lit particle can burn through skin, nerves, muscles and even bones. In addition, white phosphorus is very poisonous: a dose of 50-100 milligrams is lethal to the average human.
A common use of these devices is to destroy equipment to prevent its use by the enemy. A thermite grenade can disable large guns by destroying the breech or barrel. US Army issues thermite grenades to artillery units for this purpose.
Stun grenades
Stun grenades, also known as flashbangs, were originally designed for the British Special Air Service. Stun grenades are used to confuse, disorient, or momentarily distract a potential threat for up to five to six seconds. A "flashbang" can seriously degrade the combat effectiveness of affected personnel for up to a minute. The best known is the M84 Stun Grenade, commonly known as the "Flashbang", so called because it produces a blinding (1 million Candela) flash and deafening (170-180 decibel) blast. This grenade can be used to incapacitate people, generally without causing serious injury.
Upon detonation, the fuse/grenade body assembly remains intact and produces no fragmentation. The body is a steel hexagonal tube with holes along the sides which allow a blast of light and sound to be emitted. The filler consists of about 4.5 grams of a pyrotechnic metal-oxidant mix of magnesium and ammonium perchlorate.
Impact Stun Grenades - Blank Firing
A more recent development is the Blank Firing Grenade (BFIG or Blank Firing Impact Grenade). Preferred in many situations, especially training, for two main reasons; they are re-usable - and therefore more economical - because the charge is a standard ammunition blank, and they are subject to very few transport restrictions when unloaded. The BFIG contains a mechanism to fire a blank cartridge when dropped at any angle onto a hard surface from a height of a metre or more. Firing will occur in any combination of positions only on impact.
Anti-tank grenades
The first anti-tank grenades were improvised devices usually made by putting a number of fragmentation grenades into a sandbag or by tying them together. Due to their weight, these were normally thrown from very close range or directly placed in vulnerable spots onto an enemy vehicle.
Purpose-designed anti-tank grenades invariably use the shaped charge principle to produce an armour penetrating effect. This means that the grenade has to hit the vehicle at an exact right angle for the effect to work properly, which is usually achieved by the grenade deploying a small drogue parachute or fabric streamers after being thrown. The British put the first version into the field with the rifle fired No 68 AT Grenade during the Second World War, but the most widely-distributed types are Russian designs of the 1950s and later, mainly the RKG-3.
Grenades as ornamentation
Stylized pictures of early grenades, with a flame coming out, are used as ornaments on military uniforms, particularly in France (esp. French Gendarmerie) and Italy (Carabinieri). The British Grenadier Guards took their name and cap badge of a burning grenade from repelling an attack of French Grenadiers at Waterloo.
See also
- Nils Waltersen Aasen, the inventor of the hand grenade
- The grenade is also a charge in heraldry.
- Grenade is also the name of a commune in the Haute-Garonne département, in France.
References
- Cramb, Auslan (23 Feb 2004). "Battlefield gives up 1689 hand grenade." Scotland Correspondent.
- "Field Manual FM 3-23.30: Grenades and Pyrotechnic Signals." (23 Sep 2003). Department of the Army, Washington, DC.
