Sound-producing pyrotechnics

The whistling sound produced by blowing over the open end of a pop bottle is a good model to introduce the mechanism of pyrotechnic whistles. 

In some cases, the typical pyrotechnic system—prime ignition, self-contained reaction, relatively slow completion, portable —is able to furnish pure products such as oxygen gas, a metal, or a special alloy in pure state. Such systems will also be described. Not included are explosives and propellants, except in a few limited functions such as explosive sound producers, light flashes and dust explosions small-scale rocketry and propellants for confined kinetic action. 

Ellem (Ref 138, p 181) also describes pyrotechnic means of producing explosive and whistling sound. Recent advances in the art of generating oscillating light signals are described in Section 8 of this article... 

PYROTECHNIC COMPOSITION Can be a substance or a mixture of substances used to produce effects (e.g. light, sound or smoke) as a result of non-detonative, self-sustaining exothermic chemical reactions. 

Two basic audible effects are produced by explosive and pyrotechnic devices a loud explosive noise (called a "report" or "salute" in the fireworks industry) and a whistling sound. 

A pyrotechnic substance is a substance or a mixture of substances designed to produce an effect by heat, light, sound, gas and smoke, or a combination of these as the result of non—detonative self-sustaining exothermic chemical reactions."... 

Although most pyrotechnic items produce some sound, for whistles and salutes sound is the primary effect. 

When a pyrotechnic composition, whose burn rate is quite pressure sensitive, burns in a tube, a whistling sound can be produced through a mechanism similar to a pop bottle whistle. 

Pyrotechnic whistle compositions seem to burn to produce an intrinsic coilection of high frequency sounds. These frequencies are characteristic of the formulation used. 

Pyrotechnic substances include those chemicals or mixtures that undergo combustion or explosive deflagration to produce heat, light, sound, gas, or smoke. 

In World War II, the Germans used picrate whistles as a psychological adjunct to bombs and they also used pyrotechnic whistles as gas alarms. In this country, the M] 19 Whistling Booby Trap Simulator, ignited by a pull cord, produces a shrill whistling sound for 31/2 sec from a 2-in. column of Formula 156. The A/I17 Booby Trap Fksh Simulator, pull-cord ignited, starts with a whistling sound followed by an explosive flash. 

Two basic audible effects are produced by pyrotechnic devices a loud explosive noise and a whistling sound. In the terminology for noise effects, the sound effect itself is a report. The device that prodnces a report in the fireworks industry is a salute, and in the military it is a simulator. The typical composition used to produce a report, whether in civilian or military applications, is an oxidizer-metal mixture that is termed a flash powder. 

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