|Successor(s)||Armstrong Siddeley Owners Club Ltd|
|Headquarters||Coventry, England, UK|
|Key people||John Davenport Siddeley|
|Parent||Armstrong Whitworth (1919 - 1927)|
|Subsidiaries||Armstrong Whitworth Aircraft (1927–1935)|
Armstrong Siddeley was a British engineering group that operated during the first half of the 20th century. It was formed in 1919 and is best known for the production of luxury motor cars and aircraft engines. The company was created following the purchase by Armstrong Whitworth of Siddeley-Deasy, a manufacturer of fine motor cars, that were marketed to the top echelon of society. After the merge of companies this focus on quality continued throughout in the production of cars, aircraft engines, gearboxes for tanks and buses, rocket and torpedo motors, and the development of railcars. Company mergers and takeovers with Hawker Aviation and Bristol Aero Engines saw the continuation of the car production but the production of cars ceased in August 1960. The company was absorbed into the Rolls-Royce conglomerate who were interested in the aircraft and aircraft engine business and eventually the remaining spares and all Motor Car interests were sold to the Armstrong Siddeley Owners Club Ltd who now own the patents, designs, copyrights and trademarks, including the name Armstrong Siddeley.
Siddeley Autocars, of Coventry, was founded by John Davenport Siddeley (1866–1953) in 1902. Its products were heavily based on Peugeots, using many of their parts but fitted with English-built bodies. This company merged with Wolseley in 1905 and made stately Wolseley-Siddeley motorcars. They were used by Queen Alexandra and the Duke of York later King George V.
In 1909, J. D. Siddeley resigned from Wolseley and took over the Deasy Motor Company, and the company became known as Siddeley-Deasy. In 1912, the cars used the slogan "As silent as the Sphinx" and started to sport a Sphinx  as a bonnet ornament, a symbol that became synonymous with descendent companies. During World War I, the company produced trucks, ambulances, and staff cars. In 1915, airframes and aero-engines started to be produced as well.
In April 1919 Siddeley-Deasy was bought out by Armstrong Whitworth Development Company of Newcastle upon Tyne and in May 1919 became Armstrong Siddeley Motors Ltd a subsidiary with J. D. Siddeley as Managing Director. In 1927, Armstrong Whitworth merged its heavy engineering interests with Vickers to form Vickers-Armstrongs. At this point, J. D. Siddeley bought Armstrong Siddeley and Armstrong Whitworth Aircraft into his control. In 1928, Armstrong Siddeley Holdings bought Avro from Crossley Motors. Also that year Siddeley partnered with Walter Gordon Wilson, inventor of the pre-selector gearbox, to create Improved Gears Ltd, which later became Self-Changing Gears - the gearbox that should be credited with enabling the marketing tagline "Cars for the daughters of gentlemen".
Armstrong Siddeley manufactured luxury cars, aircraft engines, and later, aircraft. In 1935, J. D. Siddeley's interests were purchased for £2 million by Tommy Sopwith owner of Hawker Aircraft to form - along with the Gloster Aircraft Company and Air Training Services - Hawker Siddeley, a famous name in British aircraft production. Armstrong Whitworth Aircraft became a subsidiary of Hawker. The aviation pioneer Thomas Octave Murdoch Sopwith - Tommy, later Sir Thomas, Sopwith - became chairman of Armstrong Siddeley Motors, a Hawker Siddeley subsidiary.
Armstrong Siddeley was merged with the aircraft engine business of Bristol Aeroplane Company (Bristol Aero Engines) to form Bristol Siddeley as part of an ongoing rationalisation under government influence of the British aircraft and aircraft engine manufacturers. Armstrong Siddeley produced their last cars in 1960. Bristol Siddeley and Rolls-Royce merged in 1966, the latter subsuming the former which remained for a while as an aircraft engine division within Rolls-Royce.
In June 1972, Rolls-Royce (1972) Ltd. sold all the stock of spares plus all patents, specifications, drawings, catalogues and the name of Armstrong Siddeley Motors Ltd to the Armstrong Siddeley Owners Club Ltd. This meant that "Armstrong Siddeley" and "A-S Sphinx Logo" are trademarks and copyright of the Armstrong Siddeley Owners Club Ltd.
The "Siddeley" name survived at while longer in aviation; in Hawker Siddeley Aviation and Hawker Siddeley Dynamics before they joined with others to become British Aerospace (BAe) which with further mergers is now BAE Systems.
The first car produced from the union was a fairly massive machine, a 5-litre 30 hp. A smaller 18 hp appeared in 1922 and a 2-litre 14 hp was introduced in 1923. 1928 saw the company's first 15 hp six; 1929 saw the introduction of a 12 hp 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 30 hp, the last 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 12 hp 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. Car production continued at a reduced rate throughout 1940, and a few were assembled in 1941.
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 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 Sapphire 346 sported a bonnet mascot in the shape of a Sphinx with namesake Armstrong Siddeley Sapphire jet engines attached. The 234 and 236 Sapphires might have looked to some of marque's loyal customers like a radical departure from the traditional Armstrong Siddeley appearance. However, in truth, they were simply too conservative in a period of rapidly developing automotive design. If the "baby Sapphire" brought about the beginning of the end for Armstrong Siddeley, it was because Jaguar had launched the unitary-construction 2.4 saloon in 1955, which was quicker, significantly cheaper, and much better-looking than the lumpy and frumpy 234/236 design.
The last model produced by Armstrong Siddeley was 1958's Star Sapphire, with a 4-litre engine, and automatic transmission. The Armstrong Siddeley was a casualty of the 1960 merger with Bristol; the last car left the Coventry factory in 1960.
Cars produced by Armstrong Siddeley had designations that came from the Tax horsepower rating of their engines.
|Model name||Type||Engine||From||To||No. produced|
|Eighteen||Various||2400 cc||1921||1925||2500 inc 18/50|
|18/50 or 18 Mk.II||Various||2872 cc||1925||1926||2500 inc Eighteen|
|Twenty||Short and Long chassis||2872 cc||1926||1936||8847|
|Fifteen||Tourer, saloon||1900 cc||1927||1929||7203 inc 15/6|
|Twelve||Tourer, saloon, sports||1236 (1434 cc from 1931)||1929||1937||12500|
|15/6||Tourer, saloon, sports||1900 cc (2169 cc from 1933)||1928||1934||7206 inc Fifteen|
|Siddeley Special||Tourer, saloon, limousine||4960 cc||1933||1937||253|
|Short 17||Coupe, saloon, sports saloon||2394 cc||1935||1938||4260 inc Long 17|
|Long 17||Saloon, tourer, Atalanta sports saloon, Limousine, landaulette||2394 cc||1935||1939||4260 inc Short 17|
|12 Plus & 14||Saloon, tourer||1666 cc||1936||1939||3750|
|20/25||Saloon, tourer, Atlanta sports saloon
|16||Saloon, Sports saloon||1991 cc||1938||1941||950|
|Lancaster 16||4-door saloon||1991 cc||1945||1952||3597 inc Lancaster 18.|
|Lancaster 18||4-door saloon||2309 cc||1945||1952||3597 inc. Lancaster 16.|
|Hurricane 16||Drophead coupé||1991 cc||1945||1953||2606 inc Hurricane 18.|
|Hurricane 18||Drophead coupé||2309 cc||1945||1953||2606 inc. Hurricane 16.|
|Typhoon||2-door fixed-head coupé||1991 cc||1946||1949||1701.|
|Tempest||4-door fixed-head coupé||1991 cc||1946||1949||6.|
|Whitley 18||Various||2309 cc||1949||1953||2624.|
|Sapphire 346||4-door saloon & Limousine||3435 cc||1952||1958||7697|
|Sapphire 234||4-door saloon||2290 cc||1955||1958||803|
|Sapphire 236||4-door saloon||2309 cc||1955||1957||603|
|Star Sapphire||Saloon & Limousine||3990 cc||1958||1960||980|
|Star Sapphire Mk II||Saloon & Limousine||3990 cc||1960||1960||1|
A feature of many of their later cars was the option of an electrically controlled pre-selector gearbox.
Like many British cars of the age, there are active owners' clubs supporting their continued use in several countries, e.g. the UK, Australia, New Zealand, the Netherlands and Germany. ASOC Ltd has members worldwide and many members of the ASCC in Australia are resident overseas. In the United Kingdom, the Armstrong Siddeley Owners Club Ltd publishes a monthly Members magazine "Sphinx". In Australia, the Armstrong Siddeley Car Club publishes "Southern Sphinx" six times a year. In the Netherlands ASOC Dutch publishes also six times a year, and in New Zealand, Armstrong Siddeley Car Club in New Zealand Inc. publish "Sphinx-NZ" every month. Further details are available from the Membership Secretary, or via the ASOC Ltd and ASCC Australia websites.
Throughout the 1920s and 1930s, Armstrong Siddeley produced a range of low- and mid-power aircraft radial engines, all named after big cats. They also produced a tiny 2-cylinder engine called the Ounce, another name for the snow leopard, for ultralight aircraft.
The company started work on their first gas turbine engine in 1939, following the design pioneered at the Royal Aircraft Establishment by Alan Arnold Griffith. Known as the "ASX" for "Armstrong Siddeley eXperimental", the original pure-turbojet design was later adapted to drive a propeller, resulting in the "ASP". From then on, AS turbine engines were named after snakes. The Mamba and Double Mamba were turboprop engines, the latter being a complex piece of engineering with two side-by-side Mambas driving through a common gearbox, and could be found on the Fairey Gannet. The Python turboprop powered the Westland Wyvern strike aircraft. Further development of the Mamba removed the reduction gearbox to give the Adder turbojet.
Another pioneer in the production of the RAE engine design was Metrovick, who started with a design known as the Metrovick F.2. This engine never entered production, and Metrovick turned to a larger design, the Beryl, and then to an even larger design, the Sapphire. Armstrong Siddeley later took over the Sapphire design, and it went on to be one of the most successful 2nd generation jet engines, competing with the better-known Rolls-Royce Avon.
The company went on to develop an engine - originally for unmanned Jindivik target drones - called the Viper. This product was further developed by Bristol Siddeley and, later, Rolls-Royce and was sold in great numbers over many years. A range of rocket motors were also produced, including the Snarler and Stentor. The rocket development complemented that of Bristol, and Bristol Siddeley would become the leading British manufacturer of rocket engines for missiles.
In 1946 Armstrong Siddeley produced their first diesel engines. They were medium-speed engines for industrial and agricultural use. Initially there was a single-cylinder engine producing 5 bhp (3.7 kW) at 900 rpm and a twin-cylinder version. Each cylinder had a capacity of 988 cm3 (60.2 cubic inches). The power output and speed was progressively increased. By the end of 1954 the single-cylinder engine was rated at 11 bhp (8.2 kW) at 1800 rpm and the twin-cylinder engine 22 bhp (16.4 kW) at the same speed. In 1955 the range was extended with the introduction of a 3-cylinder engine rated at 33 bhp (24.6 kW). 
The engines were built at Armstrong Siddeley's factory at Walnut Street, Leicester until that factory closed in August 1957. Production was transferred to the factory of Armstrong Siddeley (Brockworth) Ltd in Gloucestershire and in 1958 to the factory of Petters Limited at Staines, Middlesex. The engines built by Petters were designated AS1, AS2 and AS3 to distinguish them from that company's other products. Production ended in 1962 when Petters introduced a replacement range of lightweight small high speed air-cooled diesel engines.
In April 1958 the company obtained a licence to build the Maybach MD series high speed diesel engines. Several hundred were built by Bristol Siddeley Engines Ltd after that company had taken over Armstrong Siddeley's manufacturing activities in 1959.
- Armstrong Siddeley: the Sphinx Mascot, Silent and Inscrutable
- Smith, Bill (2006). Armstrong Siddeley Motors, The cars,the company and the people in definitive detail. Dorchester: Veloce Publishing Ltd. p. 494. ISBN 978-1-904788-36-2.
- RAC Rating
- Armstrong Siddeley Air-Cooled Diesel Engines by Sid Beck in'Stationary Engine' April 1992 reprinted in Rolls-Royce Heritage Trust Sphinx newsletter 49, December 2001
- Armstrong Siddeley Motors, Minutes of Board Meeting, 1 October 1957
- Armstrong Siddeley Air Cooled Diesel Engines by Tom Smith in Rolls-Royce Heritage Trust Sphinx newsletter 54, 2004
- Armstrong Siddeley Motors, Minutes of Board Meetings, 2 April 1958 and 28 April 1958
Robert Penn Bradly: Armstrong Siddeley, the Post War Cars; Motor Racing Publications, Croydon, 1989.
Robert Penn Bradly: The 346 Sapphire explored to great depth; Pimula PTY Pvt., Bardwell Park, NSW, 2008.
Bruce Lindsay: Armstrong Siddeley, the Sphinx with the heart of gold; Lindsay family trust, Thailand, 2010.
Bill Smith: Armstrong Siddeley Motors; Veloce Publishing, 2008.
|Wikimedia Commons has media related to Armstrong Siddeley vehicles.|
- Armstrong Siddeley Owners Club for the cars
- Non-affiliated Internet forum for Armstrong Siddeley enthusiasts world-wide