Spec sheet for it was:
Twenty four-cylinder liquid-cooled horizontally-oppses H-shaped, sleeve-valve engine
Take off Power 2,250hp at 4000rpm Bore 127mm (5.0in) Stoke: 121mm (4.75in) Weight 1066KG (2350lb) Other Info: Engine Manufactuters such as D. Napier began work on a new classof very powerfull piston engines in the mid 1930s. To meet the demand for a 2000hp engine Napiers produced a liquid cooled 24-cylinder horizontally oposed 'H“ type fitted with two geared crankshafts. The New engine passed its Type Tests in 1939 and entered service with the RAF a year later.