How was World War II fought?
Weapons used in World War II
World War II was fought with a wide variety of weapons from all countries that fought in the conflict. As the war progressed, new and more deadly weapons were deployed on the world's battlefields.

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By the twentieth century, the major industrialized powers of Eurasia and the Western Hemisphere had created standing armed forces based on some combination of voluntary and coerced service by their male populations. These forces are divided according to mission and operating environment into three services: ground forces (armies); air forces; and naval forces (navies). Marines are naval forces designed for amphibious operations and are considered a fourth service in some countries such as the United States. In the field, military services might operate under a single commander or not, as the case may be.

Air forces—the most recent creation—sometimes have full status independent of a nation’s army and navy, depending on interservice politics, strategic imperatives, and other nonmilitary factors. Germany, for example, had an autonomous air force, the Luftwaffe, that controlled airborne divisions, air base defense forces of ground divisions, massive anti-aircraft artillery forces, and its own prisoner-of-war camps for Allied aircrew men.

The naval forces of World War II had two essential components: operational fleets of ships and aircraft, such as the Imperial Japanese Combined Fleet, and shore establishments. Operational fleets tended to be organized as type commands of similar ships and aircraft for administrative and training purposes and task forces, task groups, and task units organized for actual operations. Submarine forces were type commands that often conducted their own campaigns but might also form part of task forces in fleet engagements. A fleet might be a combination of operational ships and aircraft in task forces, type commands, and a shore establishment.

Britain had an independent air force—the Royal Air Force—but in 1937 allowed its navy to create its own air force for fleet operations, the Fleet Air Arm. Yet the RAF, with its Coastal Command, still conducted its own naval campaign against the German U-boats. The United States and Japan created separate air forces as part of both their armies and navies. The Soviets created one air force subdivided into two functional air forces—one to support ground forces, the other to provide air defense.

The Germans and Japanese kept their services separate and their allies subservient. The Anglo-American Allies created a framework for coalition warfare that strengthened national and service cooperation. The highest level of coalition command was the theater, defined principally by geography but influenced by the preponderance of national interest and commitment of national forces.

Before men fought on horses or from boats, they attacked one another with their feet planted on the ground, thus defining war as the combat of foot soldiers or infantry. Even in World War II most infantrymen walked into battle, even if they reached the front by train or truck. Infantrymen did not inflict the most casualties, but they certainly suffered the majority of them in their effort to destroy enemy ground forces, seize key terrain, capture air and naval bases, occupy farmlands and cities, and generally represent the permanent conquest of an enemy by coming onto his land to stay unless driven off.

By World War II, infantry had joined forces with mobile artillery and gasoline-powered mechanized and motorized forces to increase the destructiveness and tempo of operations. This combination imposed cascading requirements for specialized service and support Units. These could appear in small detachments in an infantry battalion or regiment, making up however a major part of infantry divisions, or in larger formations like corps and field armies. When taking into account all the ground forces in a national army, the infantry might represent less than half of these troops.

The squadron was the essential tactical aviation unit during World War II. A squadron might be made up of as few as 6 and as many as 24 aircraft. When various ground support units were added to a squadron, it became a group. Groups might be aggregated as wings with two or more flying and support squadrons that provided personnel administration, base support and security, ordnance handling, transportation, fueling, aircraft maintenance, and communications/air control. The Soviets, holding firmly to the past, called wings aviation regiments. Larger aviation formations were called divisions and air forces. The largest were called commands or forces.

During World War II, the political leadership of all the belligerents found the existing service organizations unresponsive to what they considered they needed as special forces, defined by mission and politics. For this reason Germany created the Waffen SS, Britain the Special Air Service, Special Boat Service, Royal Marine Commandos and the Long Range Desert Group. The Americans had the Office of Strategic Services, marine raiders, parachute battalions and army rangers. The Italians had the naval commandos, the Japanese had the Special Naval Landing Forces, and the Soviets had airborne deep penetration forces.

Hitler supported SS Reichsführer Heinrich Himmler’s efforts to create within the multifunctional SS (Schutzstaffel) empire a corps of elite combat ground units, the Waffen SS. The rest of the Schutzstaffel ran the Third Reich’s national police, secret police, concentration camp, slave labor, and extermination organizations. The Waffen SS remained a ground force of 27 divisions that conducted land campaigns with the army.

Reflecting Winston Churchill’s fascination with special forces, the British organized elite units such as the Long Range Desert Group (LRDG), the Special Air Service Regiment (SAS), and the Royal Marine Special Boat Squadron (SBS), all infiltration groups for reconnaissance and raiding missions.

The American armed forces resisted such expedient organizations, fearing that special units would only weaken the regular field forces. But Franklin Roosevelt insisted on the creation of the Office of Strategic Services (OSS), which had wide-ranging responsibility for foreign intelligence gathering and assessment, propaganda and psychological warfare, subversion and sabotage, partisan warfare, and clandestine spying and negotiations. The American armed forces did provide an Air Commando (special operations wing) in Burma, marine raider and parachute battalions, army ranger battalions, and navy underwater demolition teams (‘frogmen’).

The Italian Decima Flottiglia MAS (10th Assault Vehicle Flotilla) was active from 1941 to 1943. Japan’s Special Naval Landing Forces saw extensive combat in the Pacific. Although Soviet airborne forces were mostly confined to fighting as ‘foot’ soldiers, they saw extensive action on the Eastern front.

Special forces always seemed to offer cheap and dramatic victories, like Skorzeny’s rescue of Mussolini in 1943, the Czech assassination of SS General Reinhard Heydrich in 1942, and the British raid on the great dock at St. Nazaire in March 1942. But many of their missions were aborted or resulted in catastrophic losses.

The principal belligerents of World War II shared a common legacy at least two centuries old: that military organizations would formulate and test their operational plans before a force tried to execute those plans in battle. The German Army led the world in creating regular war games and staff rides, which all other military establishments copied in varied forms.

The oldest type of activity for testing likely combat performance was the maneuver or mock battle. Restored in 17th century armies, drill was actually tactical rehearsal and testing. When extended to formations in the thousands, such drills became maneuvers, and with the appearance of formal staffs in the Napoleonic era, exercises might become war games in which nominally opposing forces faced each other in mock battle. When general staffs appeared in the 19th century, they built their expertise through professional military education and training.

Exercises of all sorts provided critical information for strategic and operational planners. They forced a realistic appraisal of enemy capabilities and intentions—or at least should have. They clarified critical decisions across the dimensions of time and space and forced some consideration of the logistical feasibility of various schemes of maneuver. They might reveal shocking limitations in methods of command, control and communications or clarify problems in task organization, weapons performance and unit training.

Military operations are the violent actions undertaken by armed forces in the pursuit of strategic objectives. Operations might take the form of a specific mission, such as landing an Allied expeditionary force in northern France, or they may be generic in nature, such as conducting amphibious assaults throughout the Pacific. They may be carried out by entire armies or by smaller forces. Operations usually have code names. The principles that shape military operations are based on centuries of experience and institutional refinement and are used almost universally. When codified and applied in training and wartime operations, such principles are called doctrine.

Operations entail armies, fleets and air forces numbering in the tens or hundreds of thousands of personnel and operating over vast distances and extended periods of time (a campaign) or activities of smaller forces for shorter periods of time.

Operations usually have codenames like Overlord (the Normandy invasion), Barbarossa (the German invasion of Russia), Zitadelle (the German offensive at Kursk), and A-Go (the Japanese naval attack on the U.S. Fifth Fleet off Saipan).

Doctrine usually applies to operations (by specifying how to conduct campaigns and extended battles) and to tactics (how to conduct a single engagement or series of similar engagements), but not to strategy. ‘Strategic doctrine’ is an oxymoron since strategy is defined by contingent war aims.

Throughout the war, various types of operations were employed by the armies of the world that clashed on the battlefield: offensive actions, defensive actions, combined arms, schemes of maneuver, turning movement, penetration, infiltration, airborne operations, amphibious operations, naval operations and air warfare.

An offensive action is a military action such as a battle or a campaign in which a combatant makes a forward movement to engage the enemy, and in so doing takes the initiative. A defensive action is a military action that usually combines some form of positional defense such as the defense of an ocean area or airspace or a ridgeline, with some form of mobile defense in which deployed forces seek opportunities for a counteroffensive once the enemy’s offensive intentions are clear. A defender may trade time and space in order to minimize losses, taking advantage of changing terrain and weather to disrupt the enemy’s forward movement.

Types of movement made by attacking forces that aim to produce high enemy casualties, destroy unit cohesion, and demoralize the enemy forces are called schemes of maneuver. The simplest such action is a frontal attack or assault, which pits an attacker directly against a defender’s strength but may have the advantages of surprise and superiority of combat power. An envelopment seeks to place overwhelming combat power on a vulnerable flank (side) of the enemy’s deployed forces. A turning movement is a flanking action that aims to change a strategic relationship by opening a new campaign theater or adding a new area of engagement to an ongoing campaign.

A penetration is an essentially linear action in which an attacking force ruptures enemy defenses, usually by massing forces with superiority in numbers, mobility, and firepower. A successful penetration allows the attacker to destroy enemy reserves behind the defensive line and to disrupt enemy command and logistical organization. An infiltration is the undetected movement of attacking forces through enemy advanced positions and main defenses, for the purpose of opening an engagement in an enemy’s rear areas or against more distant (and less alert) reserve forces. Such operations involve ambushes, roadblocks and surprise attacks.

An amphibious operation is an action in which seaborne ground combat forces land on beaches defended by the enemy in order to seize an island or a continental landing point. In World War II, the first requirement was air and naval superiority in the objective area so that amphibious shipping could conduct undisrupted landing operations. If the landing forces could not avoid an enemy ground defense force, the landing became an amphibious assault by the ship-to-shore movement of troops carried in amphibian tractors or beaching ships and craft. The lightly armed assault troops required fire support from naval guns and aircraft to overcome enemy beach defenses.

A permanent combat or a task force that integrates units of different combat capabilities to improve combat effectiveness constitutes a combined arms unit. The concept usually suggests an ability to operate with surprise, shock action, overwhelming firepower, and mobility against an enemy. A ground-combat combined-arms force, for example, would include elements of infantry, artillery, armor, engineers, and communications along with some logistical sustainability.

An airborne operation is an action in which parachute infantry drop from transport aircraft, followed by air-landing units that are flown to the secure drop zone or landing area in towed (unpowered) gliders or transport aircraft. All the major World War II belligerents developed airborne operations forces, ranging from companies to armies, to conduct airborne operations.

Air warfare is broadly defined military activity consisting of two components: strategic air campaigns, waged by aircraft that bomb a country's infrastructure, and tactical air campaigns targeted at enemy military bases and air, sea, and ground forces engaged in an active campaign. A naval operation is a military action fought by navies against other navies for control of the sea. Sea control is essential to naval operations. In World War II, naval operations involved attacks on fleets by carrier aircraft, land-based aircraft (usually long-range bombers), warships firing naval guns and torpedoes, and ships that laid mines.

Tactics are the discrete actions taken by ground combat units, aircraft, and ships and their personnel in order to defeat the enemy in battle. Tactics kill people and destroy things. Tactics may also refer to tactical doctrine—institutionally recommended ways of fighting used to train individuals and units before they enter combat. Aerial combat by fighter aircraft in World War II depended on pilot gunnery with machine guns and cannons. In naval combat, surface warships made zigzag maneuvers to avoid enemy shells, torpedoes, and aerial bombs. In tank warfare, maneuverability, firepower and armor had to be balanced.

Successful combat leadership and unit performance usually result from a combination of sound tactical doctrine and the flexibility to apply and adapt that doctrine under fire, according to battlefield conditions. Tactical performance depends on a thorough understanding of both weapons systems and human factors like morale, training, enemy capabilities, fatigue, unit cohesion and small-unit leadership.

A few air pilots were superior marksmen, but most were unable to choose the proper range and angle of attack against an elusive foe. Moreover, pilots had to be alert to their oxygen supply, which was affected by both altitude and gravity in steep, fast dives and sharp turns. Blacked-out pilots, deprived of blood flow to the brain, did not fly well.

Naval zigzag maneuvers had to be adjusted to allow a ship’s batteries to make accurate target-lying for their own salvos.

American and Soviet tanks tended to be more maneuverable, but German tanks took the lead in main gun lethality, measured by range, sighting and gun-shell penetrating characteristics. German tanks also carried heavier frontal armor. Therefore, even with better main guns, Allied and Soviet tank crews had to look for side angle and rear shots at close range to destroy or at least cripple German heavy tanks, whose crews placed a high premium on driver-gunner coordination and the clever use of terrain for cover and concealment. Allied and Soviet tanks fought and survived best when engaged as pairs and groups of three.

Logistics refers to the material support and movement of armed forces. It always influences, and often determines, the outcome of warfare. The United States and British Commonwealth required thousands of ships to supply their forces around the world. Germany relied on railroads to serve its continental forces on three fronts. Japan moved supplies by sea to its Pacific bases and by sea and rail to China. However, logistical activity entails more than just transportation. For military equipment, important considerations are mass production, standardization, and simplicity. The United States and the Soviet Union allowed for rapid replacement of destroyed weapons.

The flow of supplies varied depending on calculations of need (for training, routine combat, or emergency combat) and the distribution system. Requirements might come from providers (‘push’ logistics) or from requests by users (‘pull’ logistics). Planners in World War II became intimately familiar with concepts like ‘days of fire’ for shell consumption, steaming miles for warships, and flying hours for aircraft.

In addition to procuring and distributing supplies, military forces try to keep their durable goods in use through maintenance and repair, supplemented by recovery and salvage operations. A tank that blows up may leave a salvageable track; a tank with an inoperable track can be recovered and repaired.

Medical services are logistical requirements, at least until the wounded are out of a combat zone. At the operational level, military medical services focus on the emergency treatment, collecting, classification (triage) and evacuation (clearing) of casualties. Regardless of how severe or superficial wounds may seem, they can all kill through shock, heart and respiratory failure, brain damage or catastrophic bleeding. The quicker the treatment and evacuation to emergency surgical units, the more likely a patient’s survival.

Successful commanders are almost always skilled logisticians or have expert logistical staffs and service force commanders. As one military adage goes, amateurs talk tactics, but professionals talk logistics.

The arsenals that the forces of World War II turned upon each other brought warfare to a new level. Although many types of weapons made their first appearance in World War I or even earlier, the arsenals of 1937-1945 made combat between conventional armed forces more deadly than ever. The development of aerial weapons led to the possibility of horrific attacks on civilians in cities. Area fire characterized World War II combat. The World War II armed forces did make halting steps to improve the accuracy and effectiveness of weapons, largely through artillery or electromagnetic technology such as the radar.

The mass industrialized assembly-line production of weapons made such deluges of firepower possible. The exploration of nuclear energy for destructive purposes by both coalitions represented another path of advanced research and technology in weapons design. Given the limitations of 1940s technology, the limited time for training combatants, the sheer size and complexity of the armed forces, and the demand for mass-produced weapons, the forces involved could hardly afford to push technological innovation too far. The one nation that did—Nazi Germany—lost.

Probably the single most effective killer in ground combat was the artillery and mortar forward observer team: a group of soldiers armed with binoculars, compasses, good maps and—the critical element—dependable radios. These teams, used by all armies in some form, could call for fire from full battalions of artillery, could rapidly correct and adjust concentrations of shells, and could kill soldiers and destroy all military vehicles except the heaviest tanks and assault guns.

In air and naval combat, the greatest electronic advance was radar, which propagated radio waves through the atmosphere at known distances, altitudes and speed and then measured the ‘return’ when the waves met resistance from solid objects and bounced back. The underwater variant was sonar in which ultrasonic waves penetrated water at calculable ranges and depths. An operator using radar or sonar could ‘see’ or ‘hear’ anything from a flight of enemy bombers to a hostile submarine.

In broad terms, ground combat forces—infantry, artillery, armor, anti-tank, and combat engineer units—employed weapons that served their missions and means of mobility, but all also had weapons for personal and vehicle protection that did not principally serve offensive purposes. Infantrymen fought with rifles, submachine guns, pistols, machine guns, grenades, antitank weapons and so on.

Infantrymen had to carry their own weapons, often in difficult terrain like jungles and mountains and in all sorts of unpleasant weather. Infantry used rifles, submachine guns, automatic rifles, light and heavy machine guns, hand grenades and mortars. Leaders and members of crew-served weapons such as machine guns and mortars carried pistols and light rifles or submachine guns.

The best mass-produced rifle was the U.S. M-1 Garand, which fired eight rounds from a clip, one round with each trigger pull without working a manual bolt to reload the chamber. This feature made the M-1 a semiautomatic rifle with a gas-propelled bolt when all other standard models were hand-powered bolt-action rifles. The German Mauser and British Enfield rifles had better workmanship, but the M-1 fired faster and just as accurately and could be maintained under virtually any battlefield condition.

The only officers who consistently carried swords were the Japanese, although infantrymen carried a wide variety of bayonets, knives, machetes or bolo knives, and entrenching tools that proved useful for close combat as well as digging.

Pistols (revolvers and automatics) ranged from 7mm to 9mm (.35 caliber, with some up to .45 caliber) and came in many dependable models: Luger, Mauser, Sauer, Webley, Walther, Browning, Colt, Beretta, and Tokarev.

Submachine guns and carbines were for individual protection. The automatic fire and heavy bullets of submachine guns made them popular for close combat in jungles, forests, and houses. Paired with hand grenades they were deadly killers. The German MP40 and Russian PPsH Model 1941 shared the field with the American Thompson (‘Tommy’), the Australian Owen, and the British Sten guns. The Italian Beretta was also good, while the American M3 ‘grease gun’ was heavy and accurate only at close range. Submachine guns used spring-activated bullet feeding magazines that contained up to 30 rounds, or drums with up to 50 rounds.

As infantry tactics developed during the war, foot soldiers grouped around air-cooled light machine guns in what became known as fire teams or sections. The Americans had two such weapons: the Browning Automatic Rifle and the Browning .30-caliber M1919A4 and M1919A6 light machine guns. Other armies normally had similar weapons such as the German MG34 and MG42 machine guns and the British Bren gun.

Infantry battalions and regiments had two types of artillery: lighter variants of cannon and howitzers found in artillery battalions or anti-tank (AT) cannon, and mortars with a bore size ranging from 60mm to 100mm. Heavier mortars were classified as artillery. For destroying tanks, the German Panzerschreck used an 88mm shaped-charge rocket. The American version was a 2.36-inch rocket also fired from a shoulder-held launcher or ‘bazooka,’ named for an odd comic strip musical instrument. The British had the Projectile Infantry Anti-Tank or PIAT. The German Panzerfaust was probably the best because of its large warhead and simple one-man launching tube.

After the dominance of artillery on the battlefields of World War I, no major army ignored the need for a wide variety of guns in massive numbers. Artillery pieces can be classified by several characteristics. One measure is barrel length. A short-barreled cannon is a howitzer; a long-barreled cannon is a gun. Artillery pieces can also be classified by source of mobility: siege and railway guns, medium artillery and light artillery. Another World War II variant was the assault gun, designed to blast fortified positions.

Generally, a howitzer could fire a heavier shell more accurately than a gun, but at reduced range. A howitzer shell travels a high trajectory, while a gun shell follows a flatter trajectory. A gun fires shells at a higher velocity and has greater penetrating power against tanks, fortifications, and buildings.

Siege guns and railway guns were moved on railway cars or could be pulled only by the most powerful tractors. The heaviest field guns (175mm–240mm and above) moved slowly behind tractors. Medium artillery (105mm–175mm) was normally towed by dual-drive trucks, but such guns also served as self-propelled artillery in armored formations, which meant that 105mm howitzers and some heavier guns (150mm and 155mm) were mounted on tank chassis.

The best assault gun was the German tracked Sturmgeschütz with its high-velocity 100mm gun, also a tank killer. By war’s end the Russians had a reliable family of self-propelled guns for armored warfare: the Su 76 general-purpose cannon, the Su 100 anti-tank gun, and the Su 122 assault gun with the type designators indicating cannon bore width in millimeters. Light artillery came in sizes from 57mm to 105mm, the most common being the 75mm howitzer.

Tanks provided mobile fire support for infantry, but their principal missions came from a horse cavalry heritage: reconnaissance, screening and counter-reconnaissance, the penetration of enemy defenses. As World War II continued, tanks became larger, more heavily armed and armored, and more powerful, but not faster. Their basic components never changed. Tank chassis and modified tanks became armored vehicles that supported armored warfare. The armored forces included mobile reconnaissance forces and mounted infantry (or Panzergrenadiers) to make the tank battalions less vulnerable to ambushes.

Tanks carried a main, high-velocity cannon in a turret that could usually traverse 360o, supplemented by one or two internal, forward-firing machine guns (one a coaxial machine gun, turret-mounted and aligned with the cannon) and an external heavy machine gun mounted near the turret-hatch for anti-aircraft defense. Tank crews numbered three to five men to drive the tank and fire its weapons, two or three in the turret, and one or two inside the hull.

Main guns went from 37mm in the 1930s to 88mm and 90mm by the war’s end, the former mounted in some German Panther and Tiger tanks and the latter in the U.S. M-26 Pershing. The Russian T-34 at first mounted a 75mm short gun, then switched to 76mm and 85mm long guns. Most American and British tanks were undergunned until the Pershing arrived in 1945 or until the conversion was made to the Firefly Sherman with its long 17-pound gun. The Stalin (JS II) Russian heavy tank carried the heaviest gun at 122mm when it appeared in 1944.

Tank design involved trade-offs between shape (wider and lower was better), engine choice, amount of armor on the bow/frontal plane and turret, gun size, and maneuverability over soft and steep terrain. Another consideration was the ease of mass production and field maintenance—a factor that weighed heavily with the Americans and Russians. The Panthers and Tigers started at 44 tons and reached 69 tons while the Soviet Stalin reached 53 tons.

All tanks faced common problems: the crews’ limited visibility, fuel consumption, vulnerability to catastrophic fires and ammunition explosions, and mechanical breakdowns. Design changes sometimes helped, such as switching from gas to diesel engines. However, design changes made to increase chances of survival usually meant greater weight and thus a reduction in maneuverability, speed, and the ability to cross extemporized military bridges.

Armored formations employed light tanks, which reached high speeds by sacrificing armor and mounting light guns. Light tanks performed best in reconnaissance roles by supporting scouting vehicles, but required medium tank support if engaging enemy tanks. The American armored forces in Europe created cavalry groups of medium and light tanks and armored cars to scout ahead of corps-sized formations. Attached medium tank battalions (usually only one) provided armored support for infantry divisions.

The British were especially inventive in creating tracked engineering vehicles to breach barbed-wire and minefields, assault fortifications with flame-throwers, fill trench lines, and bridge canals and ditches. It became common for British and American tank battalions to include tanks with mounted bulldozer blades. Tank chassis could mount howitzers; the U.S. M-7 Priest with a 105mm howitzer became a mainstay for American armored divisions.

There were also reconnaissance vehicles with wheels (armored cars), ranging from unarmored jeeps and Kübelwagens to multi-wheeled cannon-armed cars like the Allied M-8 Greyhound or the German eight-wheeled M234 Panzerspähwagen. Accompanying infantry rode in vehicles with wheels in front and tracks in the rear. These ‘infantry fighting vehicles’ or ‘half-tracks’ could carry light cannons, but more often carried multiple heavy and light machine guns. Most common were the German Schützenpanzerwagen and the U.S. M-3 1 half-track, each designed to carry one infantry squad.

Although aircraft themselves reached new levels of capability, none of those improvements would have brought military advantage without improvements in aerial ordnance. Most of the damage in air warfare in World War II came from unguided bombs directed at ground targets and from wing mounted machine guns used in air-to-air combat. All the belligerents developed rockets to be fired from aircraft at either ground or aerial targets. The most dramatic attempt to escape the limitations of manned aircraft came from the Germans, who developed two operational unpiloted rockets, known as the V-1 buzz bomb and the V-2 ballistic missile.

The V-1 was a cruise missile powered by a jet engine, capable of carrying a high-explosive warhead of almost a ton. Launched from canted ground rails, the V-1 had a primitive navigation system and autopilot that could not be jammed, but its accuracy was equally primitive, since only three-quarters of the buzz bombs would fall within an eight-mile radius of the theoretical aim point. Moreover, the V-1 could be tracked by radar and shot down by interceptors and anti-aircraft artillery.

Belligerents counted on manned aircraft—bombers—to carry ordnance to industrial cities, power-generating complexes, and military factories and depots. Gravity or free-falling bombs followed fairly predictable flight trajectories to earth and could be fused to explode above ground, upon contact, or after penetrating the ground or concrete buildings.

Fires and collapsing buildings killed people and wrecked production facilities with much deadlier impact than bursting bombs. An alternative to the High Explosive bomb was the incendiary bomblet. This was loaded with white phosphorus or some other chemical mixture that reached high temperatures and could not be extinguished with water. For battlefield targets, the Allies developed napalm, a naphtha-jellied gasoline that burned or suffocated enemy personnel with its searing fires.

The Germans developed a short-range ballistic missile, the V-2, carrying a ton-plus of high explosives. It was even less accurate than the V-1, but it could not be shot down because of its high speed. The Germans fired some 3,000 V-2s at targets in Britain, France, Belgium, and western Germany, causing nearly 13,000 casualties. The relatively light payload and gross inaccuracy spared crowded cities and mass military bases from catastrophic damage. But the lack of defense against the V-2 gave Allied leaders pause. Allied air and ground operations gave a high priority to destroying V-1 and V-2 rocket sites.

Rockets could serve in the ground-to-ground artillery role, used most extensively by the Soviets. Since terminal guidance systems for rockets did not reach common operational use, military rocketry sought to join light but potent warheads with high-velocity rockets fired in salvos that would go roughly where they were aimed with crude sighting devices and the Mark I eyeball. The Americans, British and Soviets pioneered the use of rockets for aircraft attacks on tanks and found that rocket attacks from above brought massed armored attacks to a confused halt. Aerial rockets also proved deadly against railroad locomotives and railcars.

Confronted with raid after raid by Allied bombers, the Germans and then the Japanese tried to use air-to-air rockets to shoot down heavy bombers, a tactic that allowed the interceptors to operate outside the range of the bombers’ machine guns. The Germans had some success with aerial rockets against bombers, but American escort fighters blunted their use against day bombers. Luftwaffe night fighters, however, found aerial rockets deadly against the RAF and even dropped aerial mines with parachutes as effective anti-bomber weapons.

Aircraft machine guns and cannons were useful against ground or air targets. Cannons often replaced machine guns as the basic air weapon, especially for ground attack fighter-bombers. The Germans and the Russians even found ways to mount a 75mm cannon in an under-carriage pod as a tank-buster. The standard armament for strategic bombers remained a combination of .30-caliber and .50-caliber machine guns. The U.S. Air Force armed the B-29 Superfortress with a 20mm cannon as well as .50-caliber machine guns.

The surface warships of World War II depended on naval guns as their main armament, with torpedoes as supplementary weapons. In addition to their main batteries, large warships carried light guns and 40mm and 20mm rapid-firing cannons as well as heavy machine guns to defend themselves from aircraft and small surface combatants. The invention of the radar allowed the navies to enhance their targeting methods. The most dramatic change in naval warfare, especially in fleet battles, came from the use of land-based and carrier aircraft to attack warships.

The heaviest guns a ship carried were called its main battery. Main batteries, however, usually meant one to three guns mounted in a turret, either alone or in pairs, fore and aft of a warship’s superstructure. Some battleships and cruisers carried turreted guns amidships for additional firepower. But such a position limited turret traverse (turn) both fore and aft. For a battleship, the common arrangement was six guns in two turrets forward and three guns in one turret aft, but other arrangements might be four turrets of two or three guns each.

The torpedo was the greatest ship-killer of World War II. It sank more warships and merchantmen than any other piece of ordnance. Although naval torpedoes of the era carried more destructive warheads than their World War I predecessors, torpedo effectiveness depended on complementary developments in fusing, propulsion systems and target acquisition. Torpedoes could be adapted to several launching platforms: submarine torpedo tubes, the launchers of cruisers and destroyers, a variety of aircraft from carrier-based planes, and large, long-distance naval reconnaissance and anti-submarine bombers.

The most dramatic improvements in torpedo lethality came from sighting and guidance systems in submarines. First, submarines and surface ships adopted automated calculators to produce firing solutions that could match the speed and direction of the submarine, the torpedo, and the victim. The next major improvement, in which the Germans led the field, was to give torpedoes some terminal guidance capability, that is, to match homing capabilities in the warhead to the characteristics of the target.

The use of radar provided a welcome alternative to optical sighting and made accurate night-shooting a real possibility at long ranges. Careful plotting with radar also allowed a naval commander or ship’s captain to keep track of friendly warships, often the unintended victims of friendly fire in battles at night or in reduced visibility. Radar-based navigation allowed warships to take evasive action with reduced risk of collision or running aground. The central functions of naval command shifted from the bridge to the combat information center, where the radars and radios did their magic.