Why the Allies Won

by Richard Overy

  The oil campaign was a chapter of disasters. German forces were divided and weakly spread over a vast geographical area. Shortages of fuel meant resort once again to large numbers of horses. When the first German forces reached the oil-town of Maikop, with its annual supply of over 2 million tons of light crude oil, they found the wells and refineries burning and demolished. German forces never reached Grozny but were stopped 100 miles west of it. The annual production here exceeded all German supplies. Beyond, on the Apsheron peninsula by the Caspian Sea, lay Baku, a city literally floating on oil. From a forest of derricks and chimneys came annually over 20 million tons of oil, three times Germany’s yearly consumption.60 At Maikop the revival of oil output was beset with difficulties. Almost nothing had been done, for all Hitler’s insistence on the economic objectives, to prepare for the revival and exploitation of the Caucasus oil. Germany was short of drills and oil-producing equipment. What drills she had were already in use in Germany and Austria, in the search for new sources of natural oil. There were few oil technicians to spare. A group of forty experts sent to Maikop were housed in a large barrack block with German guards at the door, but during the night Soviet partisans broke in and slit their throats. There were severe food shortages for the oilworkers. When the drilling equipment was finally prepared for transit it was held up in the overtaxed rail network and had not reached Maikop by the time Soviet armies recaptured the town. All Germany acquired during the period of occupation was 70 barrels of oil a day.61

  The defeat at Stalingrad completed the rout of the oil offensive. Germany was forced to rely on synthetic production and Romania for the rest of the war. Oil supply from these sources reached a peak in 1943 and then declined sharply. In 1944 Germany received less than half the oil from Romania supplied in previous years. The Allies had long regarded oil as the German Achilles heel. The British and French planned to attack German sources of oil supply from the air in 1939 and 1940 but lacked the technical means to do so.62 During 1944 the bombing offensive was used to impose an aerial oil blockade on Germany. The Romanian fields at Ploesti, one of the most heavily defended targets in Europe, were attacked first on 5 April, and were then bombed heavily until 19 August, the day before the Soviet invasion of Romania forced her to change sides and cut off all supplies of oil to Germany. The Danube had been mined by British bombers, reducing traffic along the river from Romania by two-thirds.63 Germany was compelled to rely more and more on home production, but in May 1944 the Allied bomber forces began a systematic assault on synthetic oil production. The impact was immediate. In June synthetic output fell by 60 per cent; by September it had been reduced to a mere 10 per cent of the output before bombing began. The American air force mounted 127 oil attacks, the RAF some 53. From the summer of 1944 the German forces lived off reserved stocks. At the beginning of the year these had been kept at roughly a month’s consumption. By September 1944 they were down to a mere 150,000 tons, less than half the monthly total needed to keep the German forces in the field.64

  During the course of 1944 the lifeblood of German armoured and air forces drained away. It was impossible to fight modern war without fuel. German air training, like Japanese, was reduced to simulation. New pilots got their first taste of real flying when they reached the squadrons, and the high loss rates reflected it. Reports from every German front-line complained of the lack of oil. Tanks were dug in as artillery. Oil use was rationed to only the most essential operations. The shortage of aviation fuel in particular – down by September to 5 per cent of its peak production level that year – gave the Allied air forces virtual command of the skies, allowing them to attack Germany’s meagre oil supply lines at will. Even had the modern weapons been available in sufficient quantity, the problem of driving and flying them was insuperable. Both Germany and Japan gambled that they could win with careful use of their existing oil supplies and the seizure of oil-producing regions, but in reality oil remained a vulnerable aspect of their war efforts, and one that limited the extent to which their forces could be armed and supplied with modern petrol-driven equipment. The oil shortage was exacerbated by enemy action. The seaborne blockade of Japan and the aerial blockade of Germany were deliberately designed to exploit this Axis vulnerability.

  It would be wrong to argue that oil determined the outcome of the war on its own, though there could scarcely have been a resource more vital to waging modern combat. Because they had sufficient supplies, the Allies enjoyed a much greater flexibility both in choosing the structure of their forces and deciding how to use them. But even the Allies, for all their preponderant supply of oil resources, were not free of oil problems. Soviet production fell by almost half thanks to the disruption of the industrial economy, and the supply of high-grade aviation fuel was made possible only by importing chemicals from America to upgrade Soviet fuels. Britain fought for much of 1942 and 1943 to keep open the oil supply lines from the Americas across the Atlantic, and to guard the gateway to Middle Eastern oil in Egypt, Even the United States, endowed with more oil than the rest of the world together, could not simply turn on the tap. California alone produced more than the Soviet Union, but there were no pipelines running eastwards, and west coast oil went largely to fuel the Pacific war. After a decade of low output and prices the oil industry suddenly found itself faced with demands from the armed forces and America’s allies that it could barely meet. A state oil commissioner was appointed to plan the expansion of output. The choice fell on Roosevelt’s Secretary of the Interior, Harold C. Ickes. He was a politician of the New Deal, far too liberal for the oilmen. Ickes swallowed his scruples and built bridges to the industry. Government investment and subsidies poured into some of America’s largest and richest corporations.65

  There were two particular problems to be solved. The first was to find a safe way of getting oil to the main industrial areas of the east and north-east in the face of the German submarine threat to the oil supply routes along the coast. At the beginning of the German-American war tanker tonnage took heavy losses. Petrol rationing was introduced in the eastern states, and speeds restricted to 35 miles per hour. Ickes urged the industry to build new pipelines to deliver the oil across country. So began the construction of the ‘Big Inch’ pipeline, one of the largest engineering projects undertaken anywhere during the war. The pipe was in fact 24 inches in diameter, and ran from Longview in Texas to Phoenixville, Pennsylvania. It was designed to carry 15 million tons of oil a year. Pumping stations were constructed every 25 miles along its 1,380-mile course. The line was completed in 1943.66

  The second problem was the production of high-octane fuel for aircraft. Hundred-octane fuel produced much better performance than the 87-octane fuel used by the Luftwaffe. It allowed aircraft longer range, greater manoeuvrability, and those surges of power that gave Spitfires the edge over the Messerschmitt-109 in 1940. In 1940 the United States produced fewer than 40,000 barrels of it a day. Ickes pushed hard for another great engineering effort to expand 100-octane production above all else. By 1944 the United States produced over 90 per cent of the Allies’ high-octane fuel, more than half a million barrels a day.67 American production made it possible to sustain a vast navy, the bomber fleets of both western Allies, and a fully motorised army. Though the distribution of supplies never worked perfectly – the shortage of fuel for Patton as he raced across France is the most notorious example – the oil weapon gave the Allies the means to exploit the modernisation of their forces to the full. At the dinner for Churchill’s birthday in the middle of the Teheran conference Stalin stood up to propose one of many toasts: ‘This is a war of engines and octanes. I drink to the American auto industry and the American oil industry.’68

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  The only way the Axis states could have reversed the technological balance decisively was by finding entirely new weapons. In effect that meant the atomic bomb. A great many technical novelties were proposed on both sides, but nothing approached the unique destructive power of atomic energy. Every combatant knew by the
war that atomic physics might have a military application, but only the United States was able to turn this knowledge into a usable atomic weapon by the war’s end.

  Japanese scientists pursued a number of secret weapons, none more bizarre than the ‘death ray’. By the end of the war they had developed an electronic device based on a high-frequency electromagnetic wave tube emitting 13-foot waves that could stop a petrol engine at a short distance, or kill a rabbit at 10 feet from haemorrhages of brain and lungs. The plan to turn the ray on enemy bombers never materialised.69 Atomic research got little further. Japanese physicists were well aware that a bomb was a possibility, and that their American enemy was working on just such a project, but they did not believe that any power could produce one within the likely period of conflict. The Japanese navy began exploratory experiments in 1942, working with Japan’s leading atomic scientist, Yoshio Nishina, a pupil of the Danish physicist, Niels Bohr. The navy was more interested in the prospects for nuclear propulsion – given the shortages of oil – but by March 1943 naval researchers could see that the likelihood was poor and abandoned atomic research. Nishina switched loyalties to the Japanese army, which would not collaborate with its sister service, and continued to pursue the separation of the vital U235 isotope of uranium which held the key to atomic fission. Neither his equipment nor method matched his ambition. By 1944 the experiments faced stalemate. The money and high-quality scientific equipment Nishina wanted could not be spared from the war effort. When he complained to his army contact that he still needed 10 kilograms of U235 to make a bomb, the general replied, ‘Why not use ten kilograms of a conventional explosive?’70 Four months after this interview B-29 bombers hit Nishina’s laboratory. The wooden building burnt to the ground; Japan’s atomic weapons programme was reduced to ash.

  The prospects for producing atomic weapons were much greater in Germany. Much of the pioneering work in atomic physics was German. Germany was endowed with extensive scientific resources, and an outstanding scientific community, even after the emigration of distinguished scientists to the west in the 1930s. It was a German chemist, Otto Hahn, who published in January 1939 the first paper to demonstrate that the nuclear fission of uranium was a possibility; this was the process at the heart of nuclear power. The fruits of overseas research were freely available in the scientific periodicals. In the spring of 1939 German physicists grasped that the energy released in the fission of uranium would be sufficient not only to produce a new source of fuel, but also to create an explosion that would dwarf those produced by conventional weapons. On 24 April 1939 the Hamburg chemist Paul Harteck, a Nazi Party member who had worked in Cambridge in the 1920s with Ernest Rutherford, the New Zealand physicist who first split the atom, wrote to the Army Ordnance Office with news of the potential new weapon: ‘That country’, he warned, ‘which first makes use of it has an unsurpassable advantage over the others.’71 The same month the German Education Ministry set up a high level nuclear research team; in September many of its resources were absorbed by an even larger project funded by the German army. In December 1939 Werner Heisenberg, Germany’s outstanding theoretical physicist, submitted to the research team a paper that outlined in detail how a nuclear reactor worked, and the possibility of an atomic bomb.72

  Over the next two years the research teams pursued the practical issue of turning these theoretical insights into a usable product. Nuclear fission required processes of exceptional complexity and expense. Uranium, the heaviest known element in 1939, contains two isotopes. The first, U238, makes up 99.3 per cent of the metal; the other, U235, a mere 0.7 per cent. The preponderant isotope absorbs free neutrons in the element and keeps it stable, but neutrons can divide U235 and create a chain reaction, which releases enormous kinetic energy. To create a bomb it was necessary to increase the number of unstable isotopes until a sufficient mass of fissionable material was available to cause an explosion. Uranium, when bombarded with neutrons, also produced a new artificial element made up of U239 isotopes. This new element, numbered 94, was christened plutonium. It was found to be as fissile as U235, and promised an alternative source of material for bomb-making. Both the production of additional U235 isotopes and of plutonium were examined, but the army opted for enhanced uranium, and so this was where most of the German research effort was concentrated until 1945.

  There were several ways of producing more U235. It could be done electro-magnetically, as it was at the Oak Ridge facility in the United States later in the war. Or it could be produced by adding a moderating material which could slow down the neutrons in uranium without absorbing them. This allowed the neutrons to avoid the U238 isotopes, which absorbed them only when they moved at higher speeds, and to divide the U235 isotopes instead. Heisenberg suggested a number of moderators: pure graphite was one, and another was so-called heavy water (D2O or deuterium oxide), produced by removing hydrogen atoms from ordinary water by electrolytic conversion. Graphite was required for the army’s rocket research programme, and so by default the choice fell on heavy water. The more effective electro-magnetic method was ignored. Europe’s only source of heavy water lay in Norway, at the Norsk Hydro plant at Vermork. Production was time-consuming and costly. In February 1943 the plant was successfully sabotaged by the Norwegian resistance. By the end of the war German scientists had 2½ tons of heavy water, only half the quantity needed even to begin serious production of fissile material.73

  In early 1942 the army gave up on the project. The prospect of producing a weapon in time for it to be used seemed remote. The Education Ministry once again assumed responsibility; atomic physicists were ordered to use their time for more immediate war-work, and neither a nuclear reactor nor adequate quantities of enhanced uranium were ever produced. Research work continued, interrupted by bombing and evacuation, but when Allied intelligence teams scoured Germany in 1945 for scientists and laboratories they found that Germany was still years from producing an atomic weapon. Some German scientists blamed the system with its excessive compartmentalisation and political interference; others, Heisenberg among them, argued that they had deliberately dragged their feet to prevent nuclear weapons falling into Hitler’s hands.

  The truth is more complicated. Whatever the views of Germany’s scientists, Hitler remained hostile to the whole project. Without the wholehearted support of the political leadership the atomic programme was unable to generate the huge resources of labour, materials and brain power necessary. Though Hitler saw himself as an expert on guns and tanks, he found the principles of modern physics hard to grasp and disliked discussing them. Party scientists branded much of the new work as non-Aryan, ‘Jewish physics’. When Speer tried to talk to him about the research Hitler condemned it as ‘a spawn of Jewish pseudo-science’. He retained the fear that nuclear explosions would prove incapable of control, and might burn up the hydrogen in the atmosphere, destroying the globe. Nothing that was presented to him during the war carried sufficient conviction about the short-term feasibility of atomic weapons to disperse that scepticism.

  Hitler did not bring nuclear physics to a halt, but the research lacked the urgency of other more pressing armament projects. The potential scale and expense of the task, given the uncertainties still evident in atomic physics, weighed heavily against committing resources to it. Though German scientists knew of American research they remained reasonably confident that they were ahead in the atomic race throughout the war, despite its low priority. This arrogant assumption, shared, it should be added, by the anxious enemy, was the product of a science establishment heavily weighted towards pure theory. When the theoreticians turned to the practical development of the ideas they ran into difficulties. The experimental physicists were looked down upon, and the practical problems in producing atomic energy were neglected. Lacking a solid experimental foundation, Heisenberg undermined the whole development by insisting that a uranium bomb needed only a small amount of U235 to achieve critical mass (the American project required 30 pounds), and by arguing that a chain reac
tion could not be controlled. There were practical researchers who by the middle of the war had discovered that one of the best ways of producing fissile material was to employ extremely low temperatures (at Oak Ridge the Americans used liquid helium to achieve this). Harteck realised in 1941 that low-temperature reactors would solve the production problems, but was denied the uranium to verify his findings. Another researcher, Baron Manfred von Ardenne, who worked, improbably, for the German Post Office, successfully developed the method of electro-magnetic isotope separation.74 Neither idea was taken up by the elite of theorists who dominated the field. Was this a form of resistance, or sabotage? or was it simply that they failed to grasp their significance? Did it reflect professional self-interest? or a genuine belief that a workable bomb was many years off? No doubt moral scruple played a part with some of Germany’s science community, but there were enough scientists who supported the war effort and understood the nature of the atomic bomb to have produced a nuclear capability if the regime had been enthusiastic enough. As it was, the scepticism was borne out by events; even the Americans, with vast resources, 150,000 workers, and top priority for the project, failed to produce a bomb until the war in Europe was over.

  Just what a difference Hitler made in the field of research and development was evident from the fate of the German rocket programme. Rocket research dated back to the 1920s, fired by the seminal work of a German-speaking Transylvanian, Hermann Oberth. His book The Rocket into Interplanetary Space, first published in 1923, provided the theoretical frame; but when Oberth tried to build a liquid-fuelled rocket in 1929 as publicity for the Fritz Lang film The Woman in the Moon the project was a technical disaster. The furore over Oberth’s rocket attracted the attention of the German army, which began a programme of rocket development initially with Oberth’s assistance. In 1932 the army decided the project was so important that it set up its own top-secret laboratory. The first employee was a twenty-year-old student at the Berlin Technical High School, Wernher Freiherr von Braun. Despite his youth, von Braun had grasped the principles of rocket propulsion, and led the way in developing the first generation of army rockets. By 1935 enough was achieved to secure generous funding and the cooperation of the fledgling Luftwaffe. The two services combined their research on a remote and barren stretch of the Baltic coast, at Peenemünde. Here laboratories, production facilities and giant rocket launchpads were built under the leadership of an ex-captain of artillery, Walther Dornberger.75