Tizard Mission

In the late September 1940 during the Battle of Britain in the Second World War, a delegation arrived from the UK in the United States on a mission instigated by Henry Tizard, known as the Tizard Mission.

Tizard was a British scientist and chairman of the Aeronautical Research Committee which had instigated the development of radar.

The objective of the mission was to cooperate in science and technology with the US which was neutral and in many quarters unwilling to become involved in the war. The US had greater resources for development and production which Britain desperately wanted to use. The information provided by the British delegation, subject to carefully vetted security procedures, were some of the greatest scientific advances made during the war: Radar (in particular the greatly improved cavity magnetron), details of Frank Whittle‘s jet engine and the Frisch-Peierls memorandum, which described the feasibility of an atomic bomb. However many other items were also taken such as designs for rockets, superchargers, gyroscopic gunsights, submarine detection devices, self-sealing fuel tanks and plastic explosives.

Britain was particularly interested in the Norden bombsight, but previous attempts at trading technology had problems in deciding whether the information exchanged was a good bargain. The American Congress had many proponents of neutrality for the USA and so there were further barriers to co-operation. Tizard decided that the most productive approach would be simply to give the information and use America’s productive capacity. Neither Winston Churchill nor the radar pioneer, Robert Watson-Watt, initially were in agreement with these tactics for the mission. Nevertheless, Tizard first arranged for Archibald Hill, another scientific member of the committee, to go to Washington to explore the possibilities. Hill’s report to Tizard was optimistic.

At the end of August, Tizard went to the US by air to make preliminary arrangements. The rest of the mission followed by ship, arriving in Halifax, Nova Scotia on 6 September and going on to Washington a few days later. The team of six assembled in Washington on 12 September 1940. They were:

Bowen was allowed to take ‘Magnetron Number 12’ with him. After spending the night under Bowen’s hotel bed, it was strapped to the roof of a taxi to the station. An over-eager railway porter whisked it from Bowen at Euston Station to take it to the train to Liverpool and Bowen almost lost sight of it. (Inconsistently, in Liverpool the magnetron was given a full Army escort.) According to James Phinney Baxter III, Official Historian of the Office of Scientific Research and Development: “When the members of the Tizard Mission brought one to America in 1940, they carried the most valuable cargo ever brought to our shores.” The British magnetron was a thousand times more powerful that the best American transmitter at the time and produced accurate pulses[2]. The magnetron not only enabled radar small enough to be installed in night-fighters, it allowed aircraft to locate U-boats and provided great navigational assistance to bombers. It is considered to be the most significant factor in the Allied victory in the Second World War.[3]

Tizard had met Vannevar Bush on 31 August 1940, who was the chairman of National Defense Research Committee, and arranged a series of meetings with each division of the NDRC. When the American and British teams met, there was initially some cautious probing by each side to avoid giving away too much without getting anything back in exchange. At a meeting hosted by Dr Alfred Loomis on 19 September 1940 at the Wardman Park Hotel the British disclosed the technical details of the Chain Home early warning stations. The British thought the Americans did not have anything like this, but found it was virtually identical to the U.S. Navy’s CXAM radar. The Americans then described their microwave research done by Loomis and Karl Compton earlier in 1940. The British realised that Bell Telephone Laboratories and General Electric both could contribute a lot to receiver technology. The Americans had showed a Navy experimental 10-centimeter radar but had to admit that it had not enough transmitter power and they were at a dead-end. Bowen and Cockcroft then revealed the cavity magnetron. This disclosure dispelled any tension left between the delegations and things then went smoothly.

Bowen stayed in America and a few days later at the General Electric labs in New Jersey, he showed to the incredulous Americans that the magnetron worked. As a result a ‘Microwave Committee’ was set up with Loomis as Chairman. The Bell Telephone Company was given the job of making magnetrons, producing the first thirty in October 1940, and over a million by the end of the war. The Tizard mission caused the foundation of the MIT Radiation Lab, which became one of the largest wartime projects, employing nearly 4,000 people at its peak.

The Tizard delegation also visited Enrico Fermi at Columbia University and told Fermi of the Frisch-Peierls concept for an atomic bomb. Fermi was highly sceptical, mainly because his research was geared towards using nuclear power to raise steam, not atomic bombs. In Ottawa, the delegation also met a Canadian, George Laurence, who had secretly built his own slow neutron experiment. (Laurence had anticipated Fermi’s work by several months.)

When they returned in November 1940, the delegation reported that the slow neutron researches being conducted by French exiles in Cambridge, Columbia (by Fermi) and Canada (by Laurence), are probably irrelevant to the war effort. But since nuclear boilers could have some post-war value, they arranged for some financial support for the Canadian fission experiments. George Laurence later became involved in the secret exchanges of nuclear information between the British and the Americans. James Chadwick did not realise the atomic bomb was a serious possibility until Franz Simon reported to the MAUD Committee that it was feasible to separate the isotope uranium-235.

Tizard met with both Vannevar Bush and George W. Lewis and told them about jet propulsion, but he revealed very little except the seriousness of British efforts. Bush later recalled: “The interesting parts of the subject, namely the explicit way in which the investigation was being carried out, were apparently not known to Tizard, and at least he did not give me any indication that he knew such details”. Later Bush realised that the development of the Whittle engine was far ahead of the NACA project. In July 1941 he wrote to General Henry Arnold: “It becomes evident that the Whittle engine is a satisfactory development and that it is approaching production, although we yet do not know just how satisfactory it is. Certainly if it is now in such state that the British plans call for large production in five months, it is extraordinarily advanced and no time should be lost on the matter”. Bush recommended that arrangements should be made to produce the British engine in the United States by finding a suitable company.

Although the Tizard mission was hailed as a success, especially in radar, it is possibly significant that on his return to London on the 8 October 1940, Tizard found that his job no longer existed.

The mission is seen as one of the key events in forging the Anglo-American alliance. However the UK was in a desperate situation and had to give away technology that had immense commercial value after the war. The main success of the mission had been radar, but the mission opened up channels of communication for jet engine and atomic-bomb development.

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