antiaircraft weapons

Air attack, including tactical attacks against ground troops, ground installations, and naval targets as well as strategic attacks against cities, factories, and other ostensibly civilian targets as well as major military installations, was a major component of combat in World War II. Accordingly, the warring powers made extensive use of a variety of antiaircraft weapons. The antiaircraft artillery (AAA) of this period consisted of conventional artillery, sometimes improved to achieve greater muzzle velocity and, therefore, to hurl projectiles higher, and improved ammunition. Some ammunition was not only designed to maximize velocity and, therefore, altitude, but also to explode in the air, broadcasting hundreds of large, jagged-edged metal fragments, or shrapnel. This meant that a fired antiaircraft weapons 57 round did not actually have to hit an enemy aircraft to destroy it—and a distant, fast-flying target was extremely difficult to hit—but that the aircraft had merely to fly through a shrapnel burst to be damaged, perhaps fatally. The German term for antiaircraft artillery was Fliegerabwehrkanonen, typically contracted to the word flak. This contracted term was adopted by the Allies as well, not used to describe the artillery pieces themselves, but the bursting shells fired against the aircraft. Flak was most effective when fired by many massed antiaircraft guns, which thus created a "field" of flak into which enemy bombers had to fly. The likelihood of inflicting damage was multiplied in such flak barrage fields. Allied air crews often spoke of flying through flak thick enough to walk across. While flak was intended first and foremost to disable or shoot down aircraft, it was also effective directly against aircrews. Because of weight considerations, it was impossible to equip bombers with "flak-proof" armor, and many airmen were wounded or killed by pieces of flak (that is, shrapnel) that penetrated the fuselage or entered through windshields, cockpit canopies, and so on. Allied airmen were issued "flak jackets," heavy-fabric body armor, which afforded a degree of protection to vital organs. In 1944 alone, flak accounted for 3,501 American planes shot down, compared with about 600 shot down by fighter aircraft during this period. Sighting and aiming (often called by artillerists "laying") were critical to antiaircraft defense. Early in the war, sights consisted of simple arrangements of concentric rings, which yielded little accuracy. More sophisticated optical sights were developed as the war continued, as was a rudimentary computer called a "predictor." This electromechanical device could be made to follow a target, calculating its course and speed as well as the projectile's direction and velocity with the object of predicting the future position where the two would actually meet. The predictor generated information on bearing and elevation, which was fed to the gun via a pair of motors, which, in turn, automatically adjusted bearing and elevation. Because the predictor was bulky and required a large generator as well as careful calibration to align the guns to coincide with the alignment of the predictor, this device was generally installed on more-or-less permanently emplaced guns. In the field, with mobile artillery, manual sighting ("open sights") were generally more practical, despite their shortcomings. The single greatest advance in directing antiaircraft fire was radar, which was especially effective at night and in conditions of low visibility. Combined with powerful, long-range antiaircraft artillery, radar greatly extended the range of AAA fire, allowing gunners to commence firing—effectively— much earlier in an attack. Another aid to laying fire accurately was provided by the ammunition itself. Tracers were elements within the ammunition designed to burn through to the explosive and detonate the fuse if the (nonflak) round failed to hit a target. This provided an explosion clearly visible from the ground, which aided gunners in adjusting their aim for subsequent rounds. By igniting the round in the sky, the tracer also ensured that the shell would not fall back to Earth, hitting friendly targets. The term antiaircraft artillery generally refers to antiaircraft cannon, firing more-or-less heavy shells. These were used mostly to defend against large bombers making strategic attacks against cities and other substantial installations. To defend against tactical attack by lighter aircraft, including fighters, ground-attack aircraft, and fighter-bombers, light antiaircraft artillery was employed. These were essentially large-caliber machine guns, capable of firing many rounds per minute. Their range was limited, but they were effective against aircraft coming in low for tactical bombing or strafing attacks. Typically, tracer rounds were inserted into the ammunition supply (often at every eighth round), so that the gunner could more easily follow, direct, and adjust his stream of fire. GREAT BRITAIN Early in the war, London and other British cities were subject to massive German air raids, and so Great Britain developed and deployed an array of antiaircraft artillery. The most common early weapon, first produced in 1936 by the Bofors arms firm of Sweden, was a 40-mm gun commonly 58 antiaircraft weapons called the Bofors gun. The Bofors was very widely used, and it was manufactured under license by Austria, Belgium, Finland, France, Hungary, Italy, Norway, and Poland as well as by Great Britain. Those nations whose manufacturers did not license it merely copied it. Officially designated by the British the QF 40-mm AA gun, it was typically mounted on a mobile platform. It could throw a shell to an altitude of 8,400 feet. In the course of the war, the main British AAA weapon became the QF 3.7-inch Mk III, which fired a 28-pound shell to an altitude of 32,000 feet, much more effective against the high-altitude bombers that raided London and other cities. Even heavier was the QF 4.5-inch AA Mk II, which fired a 54-pound shell to an altitude of 42,000 feet and, with automated ammunition handling, could fire faster than hand-loaded weapons. The Mk II was so heavy that it also served in coastal defense as an antiship weapon. The British used a variety of light AAA, including the Swiss 20-mm Oerlikon and the American Maxson Mount, but the British firm Polsten produced the nation's own 20-mm piece, which could fire at an impressive 450 rounds per minute. Inexpensive to manufacture, the Polsten was produced and issued in great quantity for defense against low-level air attack. See also Artillery, British. FRANCE France was caught critically short of AAA at the outbreak of the war. Its most important weapon was the 25-mm Hotchkiss gun, which was used against ground as well as air targets. Although its rate of fire was rapid, its range was short, and it was not available in sufficient numbers to defend against Germany's massive tactical deployment of groundattack aircraft during the Battle of France. See also Artillery, French. GERMANY German AAA was extensively developed during World War II. Light AAA consisted of a miscellaneous host of machine gun weapons, but heavy AAA, designed to defend against the ruinous combined strategic assault of British and American heavy bombers, came in five important versions. The 20-mm Flak series consisted of many variations with a variety of mounts, but all were rapidfire weapons on a par with the British Polsten. The 37-mm Flak came in even more varieties than the smaller 20-mm Flak, including naval mounts, towed mounts, and self-propelled versions. The gun could also be permanently mounted in static locations. Germany's heavier AAA weapons included the Flak 38, Flak 40, and Flak 88. The Flak 38 fired a 105-mm shell to a ceiling of 7,218 feet. Its rate of fire was 420 to 480 rounds per minute. Too heavy to be transported readily, it was used in advanced stationary positions. The Flak 40 was a 128-mm weapon introduced in 1942. It fired twelve 26- pound shells per minute to an altitude of nearly 35,000 feet. Heaviest of all was the Flak 88, a gun of extreme versatility, which was used against ships and tanks as well as aircraft. Many weapons historians consider it the premier artillery piece of World War II. It lofted a 20-pound shell to 37,000 feet and was renowned for its extreme accuracy. See also Artillery, German. ITALY Notoriously weak in armor and artillery, Italy nevertheless fielded four significant AAA weapons. Two 20-mm guns served the light AAA function. The 20- mm Breda had the advantages of light weight and mobility, whereas the 20-mm Scotti, more numerous, was heavier but also had a high rate of fire. Italy's most important heavy AAA weapon was the Cannone DA 75/46 C.A. Modello 34, which fired a 14-pound shell to altitudes in excess of 27,000 feet. Like the Cannone DA 90/53, which followed it, the DA 75/46 was plagued by production problems, which kept the numbers deployed quite small. German forces, however, thought enough of the 75/46 that they readily took it into their AAA arsenal. See also Artillery, Italian. JAPAN World War II Japanese military doctrine emphasized rapid, highly mobile conquest. As a result, the antiaircraft weapons 59 nation produced virtually no heavy artillery and precious little antiaircraft artillery of note, relying instead on a miscellany of naval weapons and weapons captured from the Allies. The American bombers that attacked the Japanese mainland during 1944 and 1945 encountered far less flak than their colleagues flying against Germany. See also Artillery, Japanese. SOVIET UNION The Soviet Union produced some fine artillery, including the 85-mm AA Gun Model 1939, the nation's most important AAA weapon. The Model 1939 fired a 20-pound shell to 34,000 feet. As a result of the Battle of Stalingrad and subsequent Red Army victories, huge numbers of German 88-mm guns fell to the Soviets. These were used extensively to supplement the Model 1939 for fixed AAA defense. See also artillery, Soviet. UNITED STATES The principal U.S. AAA weapon was the MI 90- mm gun, which could fire a 23-pound shell to an altitude of 39,000 feet at an astounding rate of 27 rounds per minute. Ammunition was typically fitted with altimeter or radar proximity fuses for greater effectiveness. Between this behemoth and the light AAA Maxson Mount was the medium MI 37-mm AA gun, which could fire 120 37-mm rounds per minute to an altitude of 18,000 feet. The Maxson Mount, the main U.S. light AAA weapon, consisted of four .50-caliber Browning machine guns mounted on an electrically driven pedestal. With the four guns ganged in this fashion, the Maxson could pour a stream of fire at the withering rate of 2,400 rounds per minute, more intense than any other AAA weapon. Even a marginally competent gunner could achieve excellent results, provided the attack aircraft drew within range.