This dissertation presents, for the first time in the historiography, a critical aspect of British and American wartime production: how British and American aero engine manufacturers shifted from their pre-war practice of low-volume, batch production relying on highly skilled workers using standard machine tools, to large-scale production in wartime using new production methods, semi- and unskilled workers and new types of machine tools in new, larger factories. During World War II, Britain and America built over one million aero engines. The standard narrative of production in World War II is that mass production methods typically associated with the automotive industry were essential to all wartime production. In contrast, this dissertation will argue that aero engine production was not a case of simply adopting these mass production methods, nor was it a simple process of converting what some assume to have been a civilian industry to military production, using civilian factories and existing machine tools to aero engine production. Aero engines were not, and could not, be built on the assembly lines typical of mass production. This dissertation will argue that the key to large-scale production of aero engines was implementing flow production, an argument that has not heretofore appeared in the historiography of production in World War II.In comparing British and American aero engine production, the dissertation will focus on two leading aero engine manufacturers, Bristol Aeroplane Company in Britain and Wright Aeronautical Corporation in America. The dissertation will, for the first time, give a detailed picture of production of three types of air-cooled radial engines built by Bristol, the nine-cylinder Mercury and Pegasus engines and the fourteen-cylinder Hercules engine, and three types of similar engines built by Wright Aeronautical, the nine-cylinder Cyclone 9, the 14-cylinder Cyclone 14 and the 18-cylinder Cyclone 18. The dissertation will, also for the first time, provide a comparison of automobile engines and aero engines to bring out the extensive differences between them. These differences were not well understood at the time, nor later, but they had profound implications for manufacturing aero engines on a large scale. In describing the transition from low-volume batch production to large scale production the dissertation will describe how Bristol and Wright used production and process engineering to shift from the pre-war functional layout of machine tools in the factory to a system known as line production, arranging machine tools in the proper sequence of successive operations to achieve flow production, the direct and uninterrupted flow of material through the factory from raw material to finished product.The dissertation will describe how the British and American Governments organized aero engine production, bringing in the automotive industry through the shadow factory scheme in Britain and licensed production in America. Both governments financed a significant expansion of production capacity. This dissertation will provide the first detailed description and comparative study of the government-financed wartime aero engine factories in Britain and America. The dissertation will argue that aero engine factory design in Britain and America went through four generations of factories, a significant point missing in the historiography. The dissertation will show that many of the American aero engine factories were larger than their British counterparts, including what were, successively, the largest industrial single-story buildings in the world. As the dissertation will also show, American factories were different not only in size but in design and layout.Aero engine production during World War II provides a unique case in the history of machine tools, a subject not well covered in the historiography. To meet the demand for aero engines in unprecedented quantities, the aero engine manufacturers developed new types of machine tools to cope with the shortage of skilled workers and to facilitate large-scale production. Bristol and Wright replaced many standard machine tools use in their pre-war factories with special-purpose machine tools. Later, Wright developed even more efficient high-production machine tools specifically designed for aero engine production. The dissertation will describe the Greenlee Automatic Transfer machines, the epitome of these high-production machine tools, that Wright developed with the Greenlee Brothers Company.The dissertation will make clear that while Bristol and Wright were comparable companies in the pre-war years, Wright’s wartime aero engine production was on a completely different scale from production in Britain, quantitatively and qualitatively. There were significant differences between Bristol and Wright in output, size of factories, production methods and types of machine tools. The dissertation will, again for the first time in the historiography, look at comparative labour productivity and argue that labour productivity in American aero engine factories was superior to the British factories. The explanation for this difference, it will be argued, is that American aero engine factories were better suited to flow production and used greater numbers of high-production machine tools than British aero engine factories.<br/
