Technology during World War II

In the Western European Theatre of World War II, air power became crucial throughout the war, both in tactical and strategic operations (respectively, battlefield and long-range). Superior German aircraft, aided by ongoing introduction of design and technology innovations, allowed the German armies to overrun Western Europe with great speed in 1940, largely assisted by lack of Allied aircraft, which in any case lagged in design and technical development during the slump in research investment after the Great Depression. Since the end of World War I, the French Air Force had been badly neglected, as military leaders preferred to spend money on ground armies and static fortifications to fight another World War I-style war. As a result, by 1940, the French Air Force had only 1562 planes and was together with 1070 RAF planes facing 5,638 Luftwaffe fighters and fighter-bombers. Most French airfields were located in north-east France, and were quickly overrun in the early stages of the campaign. The Royal Air Force of the United Kingdom possessed some very advanced fighter planes, such as Spitfires and Hurricanes, but these were not useful for attacking ground troops on a battlefield, and the small number of planes dispatched to France with the British Expeditionary Force were destroyed fairly quickly. Subsequently, the Luftwaffe was able to achieve air superiority over France in 1940, giving the German military an immense advantage in terms of reconnaissance and intelligence.

German aircraft rapidly achieved air superiority over France in early 1940, allowing the Luftwaffe to begin a campaign of strategic bombing against British cities. Utilizing France's airfields near the English Channel the Germans were able to launch raids on London and other cities during the Blitz, with varying degrees of success.

After World War I, the concept of massed aerial bombing—"The bomber will always get through"—had become very popular with politicians and military leaders seeking an alternative to the carnage of trench warfare, and as a result, the air forces of Britain, France, and Germany had developed fleets of bomber planes to enable this (France's bomber wing was severely neglected, whilst Germany's bombers were developed in secret as they were explicitly forbidden by the Treaty of Versailles).

The bombing of Shanghai by the Imperial Japanese Navy on January 28, 1932, and August 1937 and the bombings during the Spanish Civil War (1936–1939), had demonstrated the power of strategic bombing, and so air forces in Europe and the United States came to view bomber aircraft as extremely powerful weapons which, in theory, could bomb an enemy nation into submission on their own. As a result, the fear of bombers triggered major developments in aircraft technology.

The Spanish Civil War had proved that tactical dive-bombing using Stukas was a very efficient way of destroying enemy troops concentrations, and so resources and money had been devoted to the development of smaller bomber craft. As a result, the Luftwaffe was forced to attack London in 1940 with heavily overloaded Heinkel and Dornier medium bombers, and even with the unsuitable Junkers Ju 87. These bombers were painfully slow—Italian engineers had been unable to develop sufficiently large piston aircraft engines (those that were produced tended to explode through extreme overheating), and so the bombers used for the Battle of Britain were woefully undersized. As German bombers had not been designed for long-range strategic missions, they lacked sufficient defenses. The Messerschmitt Bf 109 fighter escorts had not been equipped to carry enough fuel to guard the bombers on both the outbound and return journeys, and the longer-range Bf 110s could be outmaneuvered by the short-range British fighters. (A bizarre feature of the war was how long it took to conceive of the Drop tank.) The air defense was well organized and equipped with effective radar that survived the bombing. As a result, German bombers were shot down in large numbers, and were unable to inflict enough damage on cities and military-industrial targets to force Britain out of the war in 1940 or to prepare for the planned invasion. Nazi Germany put into production only one large, long-range strategic bomber (the Heinkel He 177 Greif, with many delays and problems), while the America Bomber concept resulted only in prototypes.

British long-range bomber planes such as the Short Stirling had been designed before 1939 for strategic flights and given a large armament, but their technology still suffered from numerous flaws. The smaller and shorter ranged Bristol Blenheim, the RAF's most-used bomber, was defended by only one hydraulically operated machine-gun turret, and whilst this appeared sufficient, it was soon revealed that the turret was a pathetic defense against squadrons of German fighter planes. American bomber planes such as the B-17 Flying Fortress had been built before the war as the only adequate long-range bombers in the world, designed to patrol the long American coastlines. Defended by as many as six machine-gun turrets providing 360° cover, the B-17s were still vulnerable without fighter protection even when used in large formations.

Despite the abilities of Allied bombers, though, Germany was not quickly crippled by Allied air raids. At the start of the war the vast majority of bombs fell miles from their targets, as poor navigation technology ensured that Allied airmen frequently could not find their targets at night. The bombs used by the Allies were very high-tech devices, and mass production meant that the precision bombs were often made sloppily and so failed to explode. German industrial production actually rose continuously from 1940 to 1945, despite the best efforts of the Allied air forces to cripple industry.

Significantly, the bomber offensive kept the revolutionary Type XXI U-Boat from entering service during the war. Moreover, Allied air raids had a serious propaganda impact on the German government, all prompting Germany to begin serious development on air defense technology—in the form of fighter planes.

The practical jet aircraft age began just before the start of the war with the development of the Heinkel He 178, the first true turbojet. Late in the war the Germans brought in the first operational Jet fighter, the Messerschmitt Me 262. However, despite their seeming technological edge, German jets were often hampered by technical problems, such as short engine lives, with the Me 262 having an estimated operating life of just ten hours before failing.[10] German jets were also overwhelmed by Allied air superiority, frequently being destroyed on or near the airstrip. The first and only operational Allied jet fighter of the war, the British Gloster Meteor, saw combat against German V-1 flying bombs[11] but did not significantly distinguish from top-line, late-war piston-driven aircraft.

Aircraft saw rapid and broad development during the war to meet the demands of aerial combat and address lessons learned from combat experience. From the open cockpit airplane to the sleek jet fighter, many different types were employed, often designed for very specific missions. Aircraft were used in anti-submarine warfare against German U-Boats, by the Germans to mine shipping lanes and by the Japanese against previously formidable Royal Navy battleships such as HMS Prince of Wales (53).

During the war the Germans produced various glide bombs, which were the first "smart" weapons; the V-1 flying bomb, which was the first cruise missile weapon; and the V-2 rocket, the first ballistic missile weapon. The last of these was the first step into the space age as its trajectory took it through the stratosphere, higher and faster than any aircraft. This later led to the development of the Intercontinental ballistic missile (ICBM). Wernher Von Braun led the V-2 development team and later emigrated to the United States where he contributed to the development of the Saturn V rocket, which took men to the moon in 1969.

The Axis countries had serious shortages of petroleum from which to make liquid fuel. The Allies had much more petroleum production. Germany, long before the war, developed a process to make synthetic fuel from coal. Synthesis factories were principal targets of the Oil Campaign of World War II.

The USA added tetra ethyl lead to its aviation fuel, with which it supplied Britain and other Allies. This octane enhancing additive allowed higher compression ratios, allowing higher efficiency, giving more speed and range to Allied Airplanes, and reducing the cooling load.

The Treaty of Versailles had imposed severe restrictions upon Germany constructing vehicles for military purposes, and so throughout the 1920s and 1930s, German arms manufacturers and the Wehrmacht had begun secretly developing tanks. As these vehicles were produced in secret, their technical specifications and battlefield potentials were largely unknown to the European Allies until the war actually began.

French and British Generals believed that a future war with Germany would be fought under very similar conditions as those of 1914–1918. Both invested in thickly armoured, heavily armed vehicles designed to cross shell-damaged ground and trenches under fire. At the same time the British also developed faster but lightly armoured Cruiser tanks to range behind the enemy lines.

Only a handful of French tanks had radios, and these often broke as the tank lurched over uneven ground. German tanks were, on the contrary, all equipped with radios, allowing them to communicate with one another throughout battles, whilst French tank commanders could rarely contact other vehicles.

The Matilda Mk I tanks of the British Army were also designed for infantry support and were protected by thick armour. This was ideal for trench warfare, but made the tanks painfully slow in open battles. Their light cannons and machine-guns were usually unable to inflict serious damage on German vehicles. The exposed caterpillar tracks were easily broken by gunfire, and the Matilda tanks had a tendency to incinerate their crews if hit, as the petrol tanks were located on the top of the hull. By contrast the Infantry tank Matilda II fielded in lesser numbers was largely invulnerable to German gunfire and its gun was able to punch through the German tanks. However French and British tanks were at a disadvantage compared to the air supported German armoured assaults, and a lack of armoured support contributed significantly to the rapid Allied collapse in 1940.

World War II marked the first full-scale war where mechanization played a significant role. Most nations did not begin the war equipped for this. Even the vaunted German Panzer forces relied heavily on non-motorised support and flank units in large operations. While Germany recognized and demonstrated the value of concentrated use of mechanized forces, they never had these units in enough quantity to supplant traditional units. However, the British also saw the value in mechanization. For them it was a way to enhance an otherwise limited manpower reserve. America as well sought to create a mechanized army. For the United States, it was not so much a matter of limited troops, but instead a strong industrial base that could afford such equipment on a great scale.

The most visible vehicles of the war were the tanks, forming the armored spearhead of mechanized warfare. Their impressive firepower and armor made them the premier fighting machine of ground warfare. However, the large number of trucks and lighter vehicles that kept the infantry, artillery, and others moving were massive undertakings also.

Naval warfare changed dramatically during World War II, with the ascent of the aircraft carrier to the premier vessel of the fleet, and the impact of increasingly capable submarines on the course of the war. The development of new ships during the war was somewhat limited due to the protracted time period needed for production, but important developments were often retrofitted to older vessels. Advanced German submarine types came into service too late and after nearly all the experienced crews had been lost.

In addition to aircraft carriers, its assisting counterpart of destroyers were advanced as well. From the Imperial Japanese Navy, the Fubuki-class destroyer was introduced. The Fubuki class set a new standard not only for Japanese vessels, but for destroyers around the world. At a time when British and American destroyers had changed little from their un-turreted, single-gun mounts and light weaponry, the Japanese destroyers were bigger, more powerfully armed, and faster than any similar class of vessel in the other fleets. The Japanese destroyers of World War II are said to be the world's first modern destroyer.[12]

The German U-boats were used primarily for stopping/destroying the resources from the United States and Canada coming across the Atlantic. Submarines were critical in the Pacific Ocean as well as in the Atlantic Ocean. Advances in submarine technology included the snorkel. Japanese defenses against Allied submarines were ineffective. Much of the merchant fleet of the Empire of Japan, needed to supply its scattered forces and bring supplies such as petroleum and food back to the Japanese Archipelago, was sunk. Among the warships sunk by submarines was the war's largest aircraft carrier, the Shinano.

The Kriegsmarine introduced the pocket battleship to get around constraints imposed by the Treaty of Versailles. Innovations included the use of diesel engines, and welded rather than riveted hulls.

The most important shipboard advances were in the field of anti-submarine warfare. Driven by the desperate necessity of keeping Britain supplied, technologies for the detection and destruction of submarines was advanced at high priority. The use of ASDIC (SONAR) became widespread and so did the installation of shipboard and airborne radar. The Allies Ultra code breaking allowed convoys to be steered around German U-Boat wolfpacks.

New production methods for weapons such as stamping, riveting, and welding came into being to produce the number of arms needed. Design and production methods had advanced enough to manufacture weapons of reasonable reliability such as the PPSh-41, PPS-42, Sten, Beretta Model 38, MP 40, M3 Grease Gun, Gewehr 43, Thompson submachine gun and the M1 Garand rifle. Other Weapons commonly found during World War II include the American, Browning Automatic Rifle (BAR), M1 Carbine Rifle, as well as the Colt M1911 A-1; The Japanese Type 11 the Type 96 machine gun, and the Arisaka bolt-action rifles all were significant weapons used during the war.

World War II saw the establishment of the reliable semi-automatic rifle, such as the American M1 Garand and, more importantly, of the first widely used assault rifles, named after the German sturmgewehrs of the late war. Earlier renditions that hinted at this idea were that of the employment of the Browning Automatic Rifle and 1916 Fedorov Avtomat in a walking fire tactic in which men would advance on the enemy position showering it with a hail of lead. The Germans first developed the FG 42 for its paratroopers in the assault and later the Sturmgewehr 44 (StG 44), the world's first assault rifle, firing an intermediate cartridge; the FG 42's use of a full-powered rifle cartridge made it difficult to control.

Developments in machine gun technology culminated in the Maschinengewehr 42 (MG42) which was of an advanced design unmatched at the time. It spurred post-war development on both sides of the upcoming Cold War and is still used by some armies to this day including the German Bundeswehr's MG 3. The Heckler & Koch G3, and many other Heckler & Koch designs, came from its system of operation. The United States military meshed the operating system of the FG 42 with the belt feed system of the MG42 to create the M60 machine gun used in the Vietnam War.

Despite being overshadowed by self-loading/automatic rifles and sub-machine guns, bolt-action rifles remained the mainstay infantry weapon of many nations during World War II. When the United States entered World War II, there were not enough M1 Garand rifles available to American forces which forced the US to start producing more M1903 rifles in order to act as a "stop gap" measure until sufficient quantities of M1 Garands were produced.

During the conflict, many new models of bolt-action rifles were produced as a result of lessons learned from the First World War with the designs of a number of bolt-action infantry rifles being modified in order to speed up production as well as to make the rifles more compact and easier to handle. Examples of bolt-action rifles that were used during World War II include the German Mauser Kar98k, the British Lee–Enfield No.4, and the Springfield M1903A3. During the course of World War II, bolt-action rifles and carbines were modified even further to meet new forms of warfare the armies of certain nations faced e.g. urban warfare and jungle warfare. Examples include the Soviet Mosin–Nagant M1944 carbine, which were developed by the Soviets as a result of the Red Army's experiences with urban warfare e.g. the Battle of Stalingrad, and the British Lee–Enfield No.5 carbine, that were developed for British and Commonwealth forces fighting the Japanese in South-East Asia and the Pacific.

When World War II ended in 1945, the small arms that were used in the conflict still saw action in the hands of the armed forces of various nations and guerrilla movements during and after the Cold War era. Nations like the Soviet Union and the United States provided many surplus, World War II-era small arms to a number of nations and political movements during the Cold War era as a pretext to providing more modern infantry weapons.

The massive research and development demands of the war included the Manhattan Project, the effort to quickly develop an atomic bomb, or nuclear fission warhead. It was perhaps the most profound military development of the war, and had a great impact on the scientific community, among other things creating a network of national laboratories in the United States. The British however started their own nuclear weapons program in 1940, being the first country to do so.[13] However, due to the potential radioactive fallout, the British considered the idea morally unacceptable and put it on hold. In 1947 the project was restarted and the first successful nuclear weapons test carried out on 3 October 1952 in Operation Hurricane and came info full service by 1955.[14] Britain was also the first to come up with the idea of nuclear energy and hint at a potential for atomic weapons in 1933. It was patented in 1934, (British patent 630,726), which help to lead the way into the further research and later, the successful development of nuclear weapons.

In 1942, and with the threat of invasion by Germany still apparent, the United Kingdom dispatched around 20 British scientists and technical staff to America, along with their work, which had been carried out under the codename Tube Alloys, to prevent the potential for vital information falling into enemy hands. The scientists formed the British contribution to the Manhattan Project, where their work on uranium enrichment was instrumental in jump-starting the project.

The invention of the atomic bomb meant that a single aircraft could carry a weapon so powerful it could burn down entire cities, making conventional warfare against a nation with an arsenal of them suicidal. Following the conclusion of the European Theater in May 1945, two atomic bombs were then employed against the Empire of Japan in August, hastening the end of the war, which averted the need for invading mainland Japan.

The strategic importance of the bomb, and its even more powerful fusion-based successors, did not become fully apparent until the United States lost its monopoly on the weapon in the post-war era. The Soviet Union developed and tested their first fire weapon in 1949, based partially on information obtained from Soviet espionage in the United States. Competition between the two superpowers played a large part in the development of the Cold War. The strategic implications of such a massively destructive weapon still reverberate in the 21st century.

There was also a German nuclear energy project, including talk of an atomic weapon. This failed for a variety of reasons, most notably German Antisemitism. Half of continental theoretical physicists—including Albert Einstein, Niels Bohr, Enrico Fermi, and Robert Oppenheimer—who did much of their early study and research in Germany, were either Jewish or, in the case of Enrico Fermi, married to a Jew. Erwin Schrödinger had also left Germany for political reasons. When they left Germany, the only leading nuclear physicist left in Germany was Heisenberg, who apparently dragged his feet on the project, or at best lacked the high morale that characterized the Los Alamos work. He made some faulty calculations suggesting that the Germans would need significantly more heavy water than was necessary. Otto Hahn, the physical chemist who had the central part in the original discovery of fission, was another key figure in the project. The project was doomed due to insufficient resources, time, and a lack of Governmental interest.

The Empire of Japan was also developing an atomic Bomb, however, it floundered due to lack of resources despite gaining interest from the government.

The collaboration between the British and the Americans led to the 1958 US-UK Mutual Defence Agreement between the two nations, whereby American nuclear weapons technology was adapted for British use.