Grenade

A hand grenade is a hand-held bomb, made to be thrown by a soldier. The word "grenade" has a Spanish origin in the word granada ("pomegranate"), in reference to the general size of early grenades. Grenadiers were originally a class of soldier specialized in throwing grenades. Some grenades are designed to be fired by a grenade launcher.

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, but works very much like a simple firecracker. A firecracker is made up of a paper body filled with gunpowder and has a small fuse. When you light the fuse, it burns down to the powder and blows the paper body apart. A grenade works exactly the same way, the main essential difference being that the grenade's fuse is lighted by a mechanical device rather than a match.

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 certain 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 pin that prevents the handle from coming off. After removing the pin and subsequently releasing the handle, the grenade will detonate in approximately four seconds.

When using a grenade, the objective is to have the grenade land with too little time for the enemy to throw it back.

One grasps the grenade in the strong hand. The grasp should include the handle. Then one pulls the pin out of the grenade. Then one estimates the time of flight to the enemy, and subtracts it from four. Then one releases the handle, counts the time not needed for flight, and throws the grenade at the intended target.

One of the classic mistakes is to grasp the grenade in the weak hand, pull the pin, and then throw the pin. (This mistake is a staple of humorous cartoons involving war.)

Another classic mistake is to fail to grasp the handle, and then pull the pin. In this case, the grenade might explode while one is calculating times.

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, yell "grenade." When a grenade is dropped into a enclosed space like a tunnel, the dropper should yell "Fire in the hole!" to alert his comrades that an explosive is about to detonate.

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. However, they contribute to the problem of unexploded ordnance.

Design and operation

The above sketch shows a cross-section of the grenade and fuse parts for a fragmentation grenade. The basic action is as follows:

1. Holding the grenade in the throwing hand, thumb over the safety lever, pull the safety pin (pull force of 10-35 pounds).
2. When the grenade is thrown (safety lever released), a spring throws off the safety lever and rotates the striker into the primer.
3. 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.
4. 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.
5. An igniter is a cap that burns rapidly. It basically sets fire to the filler causing a rapidly expanding gas which bursts the container.
6. The fragmentation grenade shown uses a detonator.

To make them easy to throw, modern US grenades are usually shaped and weigh the same as a baseball. 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 would fragment along deliberately cast weak points in the shell.

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.

Different types of hand grenades

Fragmentation grenades - designed to inflect casualties

The fragmentation grenade is an antipersonnel device that is designed to spew shrapnel in all directions. The body is made of hard plastic or steel, and flechettes or nicked wire provide the antipersonnel shrapnel fragments. Also the filler can consist of small metal balls to penetrate the target(s). (When the word "grenade" is used without qualification, and context does not suggest otherwise, this is the kind of grenade usually meant.) More info about the "frag" grenade above.

Smoke grenades

These are canister type grenades used as a ground-to-ground or ground-to-air signaling device, a target or landing zone marking device, or a screening device 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 are spread by explosive action. The 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 doubles as incendiary grenades (q.v.).

Riot control

Gas grenades to disperse large groups of people. Best known is the common teargas grenade (CS gas grenade). This grenade is in terms of shape and use similar to smoke grenades. Although, with teargas grenades, the filler consists of 80 to 120 grams of CS (Chlorobenzol malononitrile). This is a toxic chemical which (when it comes in contact with the face) causes an extreme burning sensation of the eyes and -when inhaled- throat. When the gas stays in the contact with someone for a long period of time (more than 10 minutes) it can cause burning blisters on the skin and irreversible damage to the lungs (for example lung cancer). For weak and older people CS-gas can even be fatal.

Incendiary grenades - used to destroy by heat

These kind of grenades produce extreme 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). A portion of the thermate mixture is converted to molten iron, which burns at 2204 degrees Celsius (4000 degrees Fahrenheit). It will fuse together the metallic parts of any object that it contacts. Thermate is an improved version of thermite, the incendiary agent used in hand grenades during World War II. The thermate filler of the AN-M14 grenade burns for 40 seconds and can burn through a 1/2-inch homogeneous steel plate. It produces its own oxygen and will burn under water. As a filler for incendiary grenades also white phosphorus is used, this burns at temperatures of 2760 degrees Celsius (5000 degrees Fahrenheit). (Thermate and phosphorus burns are the worst and most agonizing burns because thermate and phosphorus burn at such a high speed and temperature that one particle of those chemicals burns through almost everything (skin, nerves, muscles and even bones), even in places where there is none or little oxygen). White phosphorus is in addition, very poisonous. 50-100 milligrams are lethal.

Concussion grenades

Originally designed for the British Special Air Service, the concussion grenades are used to concuss, confuse, disorient, or momentarily distract a potential threat for up to five to six seconds. The best known is the XM84 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 will be used to apply the minimum force necessary by tactical and non-tactical forces while performing missions of hostage rescue and the capture of criminals, terrorists and other adversaries. 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 & ammonium perchlorate.

Stylized grenades used as ornament

Stylized early grenades, with a flame coming out, are used as ornaments on military uniforms, particularly in France (esp. French Gendarmerie) and Italy (Carabinieri).

Grenade is also the name of a commune in the Haute-Garonne département, in France.