Flare (pyrotechnic)
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- This article is about pyrotechnic flares. For other uses, see flare (disambiguation).
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A flare, also sometimes called a fusee, is a type of pyrotechnic that produces a brilliant light or intense heat without an explosion. Flares are used for signaling, illumination, or defensive countermeasures in civilian and military applications.
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[edit] Delivery and composition
Flares generally produce their light through the combustion of a pyrotechnic composition, sometimes based on magnesium, sometimes colored by the inclusion of pyrotechnic colorants. Calcium flares are used for underwater illumination.
Flares may be ground pyrotechnics, projectile pyrotechnics, or parachute-suspended to provide maximum illumination time over a large area. Projectile pyrotechnics may be dropped from aircraft, fired from rocket or artillery, or deployed by flare guns or handheld percussive tubes. Flares may also be dropped in the water to illuminate submerged objects.
[edit] Civilian use
In the civilian world, flares are commonly used as signals, and may be ignited on the ground or fired as an aerial signal from a pistol-like flare gun. Flare guns are commonly found in marine survival kits.
Another type of flare is the fusee, which burns for 15-60 minutes with a bright red light. Fusees are commonly used to indicate obstacles or advise caution on roadways at night; in this usage they are also called highway flares, road flares, or ground flares. They are commonly found in roadside emergency kits.
In forestry and firefighting, fusees are sometimes used in wildland fire suppression and in the ignition of controlled burns. They are especially effective in igniting burnouts or backburns in very dry conditions, but not so effective when fuel conditions are moist. Since controlled burns are often done during relatively high humidity levels (on the grounds that they could not be safely contained during periods of very low humidity), the driptorch is more effective and more often used. Fusees are also commonly carried by wildland firefighters for emergency use, to ignite an escape fire in surrounding fuels in case of being overrun by a fire if no other escape routes are available.
Fusees are also known as railroad flares and are used to perform hand signals in rail transport applications. Since they can be used only once, fusees nowadays are usually intended for emergency use (as opposed to the incandescent lanterns typically used during normal operating conditions). However, in the days before train radio communications, fusees were used to keep trains apart on un-signaled lines. A railroad fusee was timed to burn for 5 minutes and quantities were dropped behind a train to ensure a safe spacing. If a following train encountered a burning fusee it was not to pass until the fusee burned out.
Flares are routinely used in countries around Europe and South America in order to aid the build up of atmosphere. Prominent countries in Europe that use flares regularly include Germany, Serbia, Croatia, Italy and France where groups of extreme football supporters known as Ultras light flares at the beginning of games or when their team have scored.
The red flares are pyrotechnic compositions usually based on strontium nitrate and sometimes potassium nitrate or potassium perchlorate, mixed with a fuel (charcoal, sulfur, sawdust, aluminium, magnesium, or a suitable polymeric resin). [1]
[edit] Military use
[edit] Land
Ground military forces in need of a large-area illumination for artilleries or for an attack, often request the delivery of parachute-flares. Ground forces may also deploy hand-held flares for aerial or ground signaling to indicate the correct area for releasing ordnance, deploying paratroopers, or landing an aircraft. In World War II, clusters of coloured flares were deployed by reconnaissance aircraft or pathfinders to mark targets for bomber missions and supply drops.
In many militaries, the use of night vision devices has reduced the need for the use of illumination flares.
[edit] Sea
Naval flares may be employed by naval forces to illuminate undersea targets such as submarines at depth. Naval flares are also launched from anti-submarine aircraft from fixed, multi-barrel, ejectors on the sides of the fuselage.
Calcium phosphide is often used in naval flares, as in contact with water it liberates phosphine which self-ignites in contact with air; it is often used together with calcium carbide which releases acetylene.
[edit] Air
A special variety of flare is used in military aircraft as a defensive countermeasure against heat-seeking missiles. These flares are usually discharged individually or in salvoes by the pilot or automatically by tail-warning devices, and are accompanied by vigorous evasive maneuvering. Since they are intended to deceive infrared missiles, these flares burn at temperatures of thousands of degrees, incandescing in the visible spectrum as well. Soids are floating flares that are effective only in the terminal phase of missiles with infrared signature seeker heads.
[edit] Distinguish from
- Other meanings of "fusee"
