The Armstrong-Siddeley automobiles (and later aircraft engines) were an English marque manufactured from 1919 (after the company was formed in 1917 by a merger between two Coventry-based companies, Armstrong-Whitworth and Siddeley-Deasy ) to 1960.

Automobiles

The first car produced from this union was a fairly massive machine, a 5-litre 30hp; a smaller 18 appeared in 1922 and a 2-litre 14hp was introduced in 1923. 1928 saw the company's first 15hp six; 1929 saw the introduction of a 12hp vehicle. This was a pioneering year for the marque, during which it first offered the Wilson preselector gearbox as an optional extra; it became standard issue on all cars from 1933. In 1930 the company marketed four models, of 12, 15, 20, and 30hp, the latter costing £1450.

The company's rather staid image was endorsed during the 1930s by the introduction of a range of six-cylinder cars with ohv engines, though a four-cylinder 12hp was kept in production until 1936. In 1933 the 5-litre six-cylinder Siddeley Special was announced, featuring a Hiduminium (aluminum alloy) engine; this model cost £950.

The week that World War II ended in Europe, Armstrong-Siddeley introduced its first post-war models; these were the Lancaster four-door saloon and the Hurricane drophead coupe. The names of these models echoed the names of aircraft produced by the Hawker Siddeley Group (the name adopted by the company in 1935) during the war. These cars all used a 2-litre six-cylinder engines, increased to 2.3-litre engines in 1949. From 1953 the company produced the Sapphire, with a of 3.4 litre six-cylinder engine. In 1956 the model range was expanded with the addition of the 234 (a 2.3-litre four cylinder) and the 236 (with the older 2.3 litre six-cylinder engine).

The last model produced by Armstrong-Siddeley was 1958's Star Sapphire, with a 4-litre engine, automatic transmission and the badge mascot in the shape of a Sphinx with rocket engines. In 1959 Bristol Aero Engines merged with Hawker Siddeley, forming Bristol Siddeley. The Armstrong-Siddeley was a casualty of the merger; the last car left the Coventry factory in 1960.

Aircraft Engines

The company started work on their first gas turbine engine in 1939 and soon produced the Mamba and Double Mamba and later the Python turboprop engines. Further development had the Mamba lose its reduction gearbox to become the Adder turbojet.

The company went on to develop an engine for unmaned target drones , called the Viper . This was passed for developement to Bristol Siddeley and, later, Rolls Royce. It was sold in great numbers over many years.

Armstrong-Siddeley's most powerful engine was the F9 Sapphire , developed by Metrovick later Armstrong-Siddeley when Metrovick withdrew from aircraft engine manufacturing.

In 1959 Armstrong Siddeley merged with Bristol Aero Engines to form Bristol Siddeley.