The R-1340 series, nine cylinder radial aircraft engines are amongst the most significant aero engines ever produced. Almost 35,000 were manufactured over a forty year period and they remain widely used. The Pratt & Whitney Aircraft Company was established in 1925 and developed the R-1340 for the United States Navy as its first production engine. A high power to weight ratio was achieved by a cast aluminium crankcase. The design was developed continuously and power output rose from around 400 horsepower to 600 horrsepower in later production models. Reliability was a notable feature of the R-1340 Wasp. Charles Kingsford Smith's Lockheed Sirius 'Lady Southern Cross' was fitted with a Wasp engine at the time it completed the first east to west flight across the Pacfic Ocean in October- November 1934. The Wasp was widely used by civil and military aircraft including the well-known AT-6/SNJ series of military training aircraft.
In October 1937, the United Aircraft Corporation, which had taken over Pratt & Whitney, announced that a licencing agreement had been reached with the Commonwealth Aircraft Corporation in Australia for the production of R-1340 engines to be fitted to the CAC Wirraway aircraft for the Royal Australian Air Force. The first locally-built engine appeared in January 1939. A total of 680 engines were built by CAC up to 1943, all of which were fitted to Wirraways. A number of these engines were re-fitted to the post-war Ceres crop-duster conversion of the Wirraway.