Ammunition - Aeroplane Bombs

AMMUNITION - AEROPLANE BOMBS Types of Bombs.—Bombs are of two main types, explosive and chemical bombs. The explosive bombs are further subdivided into demolition and fragmentation bombs. The demolition bombs are intended for destruction of enemy works and depend pri marily upon blast or shock effect for the destruction of these structures. The destructive effect is the result of the detonation of the high explosive content of the bombs, which is usually TNT. The explosive charge constitutes approximately 5o% of the total weight of bombs. The largest size of demolition bomb ever manu factured is one weighing 4,000 pounds. Most of the bombs are streamline in shape. The present tendency in design is towards bombs which have a cylindrical body and a nose in the form of a modified ellipse either secured to or integral with the cylindrical portion. Fragmentation bombs are intended for use against per sonnel. They depend upon the fragmentation of the metal case at or above the surface of the ground to produce casualties. These bombs are much smaller than the demolition bombs, the largest weight of bomb being approximately 5o pounds. They are filled with about 15% of TNT. The main type of chemical bomb is the smoke bomb. These bombs are intended for use as obscuring agents. At present the formation of smoke screens is employed to mask known enemy observation posts, to conceal and protect the front flanks of attacking troops from enemy observation and to blind hostile machine-guns. Titanium tetrachloride and white phosphorus are the two chief chemicals used as smoke producing agents.

Bomb

Fuses.—Demolition bombs are usually equipped with both nose and tail fuses, while fragmentation bombs and chem ical bombs are equipped with nose fuses only. The fuses are of two types, the arming vane type and arming pin type. When assembled to the bomb, prior to the release of the bomb from the plane, the fuses are usually in an unarmed condition, that is, mechanical restraints prevent the fuses from firing the primer or detonator which initiates the detonation. In the case of the arm ing pin type of fuse these mechanical restraints are removed im mediately upon release from the plane, while in the case of the arming vane type of fuse all the mechanical restraints are removed only after the arming vanes have made a definite number of revo lutions due to the action of the air and the bomb has fallen a considerable distance from the aeroplane. Upon impact the firing pin of the fuse fires the primer or detonator which initiates the detonation. Where it is not desired that the bombs detonate, they are released so that the mechanical restraints within the fuses will not be removed. On impact the firing pin of the fuse is thus prevented from coming into contact with either the primer or detonator which in turn prevents detonation of the bomb. Frag mentation and chemical bombs are equipped with detonators which permit them to function instantaneously upon impact, while demolition bombs are equipped with detonators which permit of either instantaneous or delay functioning after impact.

BIBLIOGRAPHY.-Tschappat, Ordnance and Gunnery; Hime, GunBibliography.-Tschappat, Ordnance and Gunnery; Hime, Gun- powder and Ammunition; LeRoy Hodges, Post War Ordnance; L. P. Alford, Ed., Manufacture of Artillery Ammunition; Benedict Crowell, America's Munitions, 1917-1918; Whelen, The American Rifle; Mattern, Handloading Ammunition. (T, WH.)