Junkers setbacks with crashes of prototypes in 1937 and 1938. Further refinements enabled certification in 1939 and spurred South African Airways to make an initial order for two aircraft fitted with US-built Pratt & Whitney engines. Just as the aircraft was being readied for its first commercial flights, World War II began. With the outbreak of hostilities, all models were requisitioned by the Luftwaffe for military air-transport roles, and later, long-range maritime patrol. Military aircraft production was begun by the company in the 1930s and eventually monopolized all its resources. Perhaps the most notable design was the Junkers Ju 87 "Stuka"
Bristol Aeroplane Company Bristol Record Office include the papers of Lionel Harris, an engineer at the Bristol Aeroplane Company in the 1940s (Ref. 42794) (online catalogue) The Bristol Engine Company was originally a separate entity, Cosmos Engineering, formed from the pre-First World War automobile company Brazil-Straker. In 1917, Cosmos was asked to investigate air-cooled radial engines and, under Roy Fedden, produced what became the Cosmos Mercury, a 14-cylinder two-row (helical) radial, which they launched in 1918. This engine saw little use but the simpler nine-cylinder version known as the Bristol Jupiter was clearly a winning design. With the post-war rapid contraction of military