Flash Charges

Because the ignition of the aluminum in flash bulbs requires a powerful igniter mixture, special first-fire mixtures containing zirconium and potassium perchlorate have been developed and are reported in the literature.  

An unusual flash powder consists of a mixture of powdered aluminum and pyrophoric iron. The mixture is made from ferrous oxalate and aluminum heated to 475 C. The iron ignites spontaneously on exposure to air and is said to ignite the aluminum powder. 

Illumination for photographic reconnaissance at night in wartime is performed by powder mixtures or, exceptionally, by metal powders alone dispersed in air by an explosive charge. Depending on the altitude at which the unit is released, a relatively small cartridge or a much larger bomb is used. Table 12 shows five U. S. and two German items and pertinent data taken from several sources.  

Because of the destructively explosive force of the flash powder, the cartridge must be ejected from its dispenser and not exploded before a certain minimum time has passed. The M112 cartridge is furnished with delays of 1, 2 or 4 sec the larger Ml23 with 2, 4, or 6 sec. As with 

Type of Munition Altitude, ft Charge, lb Total weight Teak cp, million cp sec, million cp sec/g metal Formula 

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Flash-age fixation Flash charges Flashing membranes Flash memories Flash photolysis Flash point... 

Flash Charge of Electric Squib. Its compn is DADNPh (JAN-D-552) 20 2%, KC10g (MIL-P. 150C Grade I, Class C) 60 5%, powdered wood charcoal (JAN-C-178A) 15 2%, Nitro-starch (N 12.75% min) 5i0.5%. Another oompn... 

Moisture. Transfer an accurately weighed portion of approx 1 g of the flash charge compn to a tared moisture dish 2 inches in diameter. Place the moisture dish and contents in a drying oven at 80°—85 °C for 2 hours, cool in a desiccator and weigh. Calculate the loss in weight of die dish and contents to percent moisture in die sample... 

C percent solubility of DADNPh in ethylene chloride obtd as follows Place 0.1900 .0010g of the dry Diazodinitrophenol from the lot used in the manufacture of the flash charge composition being analyzed in a 250ml beaker and add 150ml of ethylene chloride. Heat the beaker and contents on a steam bath for 2 hours with occasional... 

Ref J. Campisi, "Development of Methods of Analysis of the Flash Charge for Electric... 

The Germans used anti-flash charges containing potassium chloride in their cannon propellants. The charges, in bags of artificial silk or cotton cloth, were loaded between the base of the projectile and the propellant. Obviously, all the additions described above increased the smoke formed when the rounds were fired. 

Zr/Ba(N03)2 46.6/53.4 1105 14 4000 215 (DTA) Flash Charge excellent stability in presence of BlkPdr, moisture, double base propint, ammonia, high altitude... 

Flash charges are also used to provide a visible indication of the functioning of an item or component such as a warhead fuze. The flash signal provides a brilliant light flash, and can be photographically recorded by remote cameras, providing... 

Ref J. Campisi, "Development of Methods of Analysis of the Flash Charge for Electric Squib , Report from the Chemical Laboratory of Picatinny Arsenal, Dover, NJ, Rept No 126836, 14 July, 1949... 

Igniter Squibs. The squibs are essentially electric detonators except that they produce a flash not an explosion. The commercial type squib, which is also used for military purposes, consists of an aluminum shell 7/8 to l-l/2w long with the flash charge in the bottom of the... 

Salutes (photo flash charges) that burn like fountains. 

The efficiency in terms of cp sec/g metal for flash charges is much inferior to that for flares. Since a much larger part of radiant emission is in that part of the infrared that can be made photographically useful with special IR sensitive film, efforts have been made along these lines. ... 

A peculiarity of the class of high-altitude flash charges is that (undoubtedly in connection with spectral emission) they are as effective in the highly rarefied atmosphere as at low altitude." " " As shown in Formulas 47—50, the spectral effects are produced by calcium either as metal or as compound, and additional advantages are gained by the presence of a sodium compound. Information on these developments is found in several Picatinny Arsenal reports." -" ... 

Flash charges are also used to indicate the point of impact of practice bombs and of small caliber spotting rounds shot from a small arms weapon with a trajectory identical to that of a larger gun. Formerly, black powder was used for such purposes, fM oviding both flash and smoke. Nowadays, a zirconium-based flash composition of 1.5 million... 

Another mixture, more modem than Hack powder but obviously also a smoky flash (though all flash charges end up as a more or less evanescent smoke puff), is described in a recent I catinny Arsenal report. It consists of a mixture of equal parts of red phosphorus and magnesium, ejected and ignited by meal powder. 

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