Flares are pyrotechnic devices designed to emit intense electromagnetic radiation at wavelengths in the visible region (i.e., light), the infrared region (i.e., heat), or both, of the electromagnetic radiation spectrum without exploding or producing an explosion. Conventionally, flares have been used for signaling, illumination, and defensive countermeasure decoys in both civilian and military applications.
Decoy flares produce electromagnetic radiation through the combustion of a primary pyrotechnic material that is conventionally referred to as the “grain” of the flare. Flares, including decoy flares, configured to emit light in a visible spectrum of light may include a grain that includes magnesium and fluoropolymer-based materials. Including or excluding certain metals or other materials in the primary pyrotechnic material may alter the peak emission wavelength emitted by the decoy flare.
Decoy flares are one particular type of flare used in military applications for defensive countermeasures. Decoy flares emit intense electromagnetic radiation at wavelengths in the infrared region of the electromagnetic radiation spectrum and are designed to mimic the emission spectrum of the exhaust of a jet engine on an aircraft.
Many conventional anti-aircraft heat-seeking missiles are designed to track and follow an aircraft by detecting the infrared radiation emitted from the jet engine or engines of the aircraft. As a defensive countermeasure, decoy flares are launched from an aircraft being pursued by a heat-seeking missile. When the aircraft detects that a heat-seeking missile is in pursuit of the aircraft, one or more decoy flares may be launched from the aircraft. The heat seeking missile may, thus, be “decoyed” into tracking and following the decoy flare instead of the aircraft.
FIGS. 1 and 2 illustrate a conventional flare 10, such as a decoy flare. Such conventional flares 10 include an elongated grain 22 that is inserted into a casing 12. The casing 12 may have a first end 14, i.e., the aft end, from which an aft end 23A of the decoy flare 10 is ignited, and a second end 16, i.e., the forward end opposite from the aft end, from which the grain 22 is ejected upon ignition. The flare 10 also includes a weighted end cap 40 that is attached to a forward end 23B of the grain 22. In some flares 10, the weighted end cap 40 may include an elongated rod 42 that is configured to be inserted into an internal bore 44 within the grain 22 to attach the weighted end cap 40 to the grain 22.
The weighted end cap 40 may be formed of a metal, e.g., brass, and may have a weight in the range of 30 grams to 50 grams. The weighted end cap 40 may be formed as a solid (i.e., monolithic) structure. The weighted end cap 40 is relatively small sized, compared to the grain 22, and relatively more dense than the grain 22. The majority of the weight of the grain 22 and weighted end cap 40, combined, is therefore distributed toward the forward end 23B of the grain 22 and, thus, of the flare 10. By locating the center of gravity toward the second end 16 of the flare 10, the weighted end cap 40 is configured to provide a stable trajectory to the flare 10 once ejected from the casing 12. In use, once the grain 22 of the flare 10 is combusted, the weighted end cap 40 remains essentially intact and falls to the ground below. The weighted end cap 40 falls below and behind the aircraft from which the flare 10 is ejected and, thus, presents danger to other airborne aircraft and ground-based building, vehicles, and personnel. Since multiple flares 10 may be fired at once during many evasive maneuvers, multiple weighted end caps 40 may form a so-called “cloud” of debris that is a danger to aircraft, building, vehicles, and personnel below.