Siddeley‑Deasy was a British motor‑vehicle and aircraft engineering company that operated in the early twentieth century.
Formation and Ownership
- The company was established in 1910 when Sir William Siddeley, a former manager at Wolseley Motors, acquired control of the Deasy Motor Car Company, which had been founded by Henry Hugh Peter Deasy in 1905.
- The merged entity was incorporated as Siddeley‑Deasy Motors Ltd., with its headquarters and principal manufacturing facilities in Coventry, England.
Products and Activities
- Automobiles: Siddeley‑Deasy produced a range of motor cars, including the Siddeley 12 hp and the Siddeley‑Deasy 14 hp models, which were marketed as high‑quality, moderately priced vehicles.
- Aircraft Engines: During the First World War the company expanded into aero‑engine production, most notably the Siddeley Puma, a 230 hp V‑12 engine used in aircraft such as the Airco DH.9.
- Aircraft Manufacture: The firm also built complete aircraft and airframes under contract, contributing to wartime production for the Royal Flying Corps and later the Royal Air Force.
Later Development
- In 1919 Siddeley‑Deasy merged with the engineering division of Armstrong Whitworth to form Armstrong Siddeley, which continued to produce both automobiles and aircraft engines.
- The Armstrong Siddeley business was eventually absorbed into the Rolls‑Royce Group in the mid‑1960s, ending the use of the Siddeley name in commercial manufacturing.
Legacy
Siddeley‑Deasy is historically noted for its role in the early British motor‑car industry and for establishing a foundation in aero‑engine design that influenced later British aviation engineering. The company's products are of interest to automotive and aviation historians, and several surviving examples of its cars and engines are preserved in museums and private collections.
