The Armstrong Siddeley 18 HP

Production period	1921 to 1927
Number of cars produced	2,500
Engine	6 cylinder, 2318cc, 18HP
Body styles	(See below)
Transmission	Manual

The 18HP was produced between 1921 and 1927, with a total production of 2,500 vehicles (which includes the 18 Mk2).

The 18HP model was released at the Olympia Show in 1921. It was a contemporary of the 30HP, only smaller and cheaper.  It was in fact a 30HP, reduced in size but not in quality.

The 18HP had a wheelbase of 10' and a track of 4' 3”. The  6 cylinder motor, with an RAC rating of 17.9hp, had two 3-cylinder castings with aluminium water jacket coverings, overhead valves and magneto ignition.  The chassis was equipped with stepboards, wings, engine starter and electric lighting complete with 5 lamps!  The price of the chassis was £575 which included speedometer, electric klaxon horn and spare tyre.

A number of body styles were available, including open touring car, saloon to seat 4 and a  laundaulette to seat 4 or 6.  In 1922 the Duke of York (later King George VI) ordered two cars based on the 18HP chassis with all timber coachwork and wood paneling. One was a rather low, pale coloured sports model with a hide leather top, whilst the other was a formal State Car