Ejection charge (commonly Black Powder), also called expelling charge, is a

pyrotechnic composition A pyrotechnic composition is a substance or mixture of substances designed to produce an effect by heat, light, sound, gas/smoke or a combination of these, as a result of non-detonative self-sustaining exothermic reaction, exothermic chemical reac ...

, a type of a pyrotechnic

gas generator A gas generator is a device for generating gas. A gas generator may create gas by a chemical reaction or from a solid or liquid source, when storing a pressurized gas is undesirable or impractical. The term often refers to a device that uses a ...

designed to produce a small short-term amount of thrust to burst open a container and eject its content. In

model rocketry A model rocket is a small rocket designed to reach low altitudes (e.g., for a model) and #Model rocket recovery methods, be recovered by a variety of means. According to the United States National Association of Rocketry, National Associati ...

, ejection charges are used to deploy a recovery system (usually

parachute A parachute is a device designed to slow an object's descent through an atmosphere by creating Drag (physics), drag or aerodynamic Lift (force), lift. It is primarily used to safely support people exiting aircraft at height, but also serves va ...

or streamer). The ejection charge is ignited through a layer of

delay composition Delay composition, also called delay charge or delay train, is a pyrotechnic composition, a sort of pyrotechnic initiator, a mixture of oxidizer and fuel that burns in a slow, constant rate that should not be significantly dependent on temperature a ...

, to fire shortly after the main engine burns out. Ejection charges can be also triggered by a timer or an

altimeter An altimeter or an altitude meter is an instrument used to measure the altitude of an object above a fixed level. The measurement of altitude is called altimetry, which is related to the term bathymetry, the measurement of depth under water. Ty ...

. A small amount of

black powder Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, charcoal (which is mostly carbon), and potassium nitrate, potassium ni ...

is usually used, but

smokeless powder Finnish smokeless powder Smokeless powder is a type of propellant used in firearms and artillery that produces less smoke and less fouling when fired compared to black powder. Because of their similar use, both the original black powder formula ...

and other compositions are possible. Ejection charge is granular black powder. Ejection charges are also used in some

flares A flare, also sometimes called a fusée, fusee, or bengala, bengalo in several European countries, is a type of pyrotechnic that produces a bright light or intense heat without an explosion. Flares are used for distress signaling, illuminatio ...

to eject the light or smoke producing components out of the flare casing. In countermeasure flares, ejection charges are used to propel the flares out of their casing, or to eject

pyrophoric A substance is pyrophoric (from , , 'fire-bearing') if it ignites spontaneously in air at or below (for gases) or within 5 minutes after coming into contact with air (for liquids and solids). Examples are organolithium compounds and triethylb ...

fluids from their containers. In

cluster bomb A cluster munition is a form of air-dropped or ground-launched explosive weapon that releases or ejects smaller submunitions. Commonly, this is a cluster bomb that ejects explosive bomblets that are designed to kill personnel and destroy vehi ...

s, ejection charges are used to disperse the submunitions. Burst charges are also used to dispense leaflets from leaflet bombs. In

chemical weapon A chemical weapon (CW) is a specialized munition that uses chemicals formulated to inflict death or harm on humans. According to the Organisation for the Prohibition of Chemical Weapons (OPCW), this can be any chemical compound intended as ...

s, ejection charges are used to disperse the chemical agent from the bomb, submunition, grenade, or warhead.

References

Pyrotechnic compositions Model rocketry {{Pyrotechnics-stub

See also

References