The Napier Cub was the world’s first 1,000 bhp aero-engine and Napier engine design E66 of 1919. The huge 60 litre capacity engine had four rows of four cylinders arranged in a squashed ‘X’ arrangement. The banks were set at 52.5 degrees (top) ad 127.5 degrees (bottom). This arrangement eased stresses on the crankshaft and made the engine easier to install.
Six prototype engies were built for evaluation and one had flight trials in the big Blackburn Cubaroo single engine bomber.
In 1925 the Air Ministry decided that it would be safer to develop multi-engined heavy bombers for the RAF. The engine design was briefy resurrected in 1926 as design E73 with engine No. 30007. In its final 1,000 bhp demonstration at Hendon Show powering an Avro 549 Aldershot, a reporter stated that the great powerof the ‘Cub’ seemed to ‘throw its aircraft around the sky’.