2017 Ariel Ace

The Ariel Square Four, with a 500 cc engine designed by Edward Turner, was launched for the 1931 season. Around this time the company went into receivership and then a new company was formed. The Square Four displacement was increased to 600cc. Throughout their history, the Square Fours had overheating problems with the rear cylinders which resulted in distorted heads. A redesign in 1937 resulted in a 995 cc OHV version designated the 4G. From 1939, Anstey-link plunger rear suspension was an option. It was still available when production restarted in 1946, with a telescopic front fork superseding the girder fork. During the Second World War the Ariel factory was turned over to military production, including the Ariel W/NG 350 army motorcycle based on the civilian NG model but with higher ground clearance frame inspired by that used successfully by Fred Povey in the ISDT.

In 1948 Ariel introduced a 500cc parallel-twin engine, following the trend that Triumph Engineering set with the Speed Twin and Tiger 100. Ariel offered the twin in two models: the low-tuned KG and slightly higher-tuned KH. In 1949 Ariel revised the Mark 1 Square Four engine to include a cast aluminium cylinder block and head in place of the cast iron components previously used, in an effort to promote cooling. With the lower weight the bike was a 90 mph (140 km/h) plus machine.

Cars were produced over two periods: from 1902 to 1915, and again from 1922 to 1925. The first proper Ariel car was a 10 hp (7.5 kW) twin-cylinder car produced in 1902. In 1903 its first four-cylinder was a 15/19 model. Both these vehicles had a leather cone clutch that was entirely separate from the flywheel. In 1904 the 15HP car had the distinction of being the first motor car to ascend Snowdon, albeit using the mountain railway trackbed which has long stretches of 1 in 5 gradient. In early 1904, Ariel began production of a six-cylinder model built on a seemingly inadequate tubular steel chassis. An entirely new range was announced at the end of 1905; called the 'Ariel-Simplex', these cars were Mercedes-inspired four-cylinder designs of 15 hp and 25/30 hp and a six of 35/40 hp. In 1907–1908 the company began production of their 50/60 hp six, which offered a 15.9-litre engine for a chassis price of £950. In 1907 Ariel sold its Birmingham factory to the French Lorraine-Dietrich company, who wanted to enter the British market; Ariel cars were thereafter assembled at the Coventry Ordnance Works, a branch of Cammell Laird. The arrangement with Lorraine-Dietrich was cancelled in 1910. Production of a 1.3-litre light car ended with the outbreak of World War I. Ariel resumed making motor cars in 1922 when it launched the Ariel Nine light car. The Nine had a 997 cc water-cooled side-valve flat twin engine with "square" dimensions of 85 mm bore and 85 mm stroke made by A Harper Sons & Bean, Ltd of Dudley. The Nine was designed by Jack Sangster, the son of Ariel's owner, who had designed the similar, but air-cooled, twin-cylinder Rover 8 when he worked for Rover. The Nine was capable of 55 mph (89 km/h) and about 700 were made. However, the engine was vibratory and noisy, so in 1924 Ariel discontinued the model and replaced it with the 10 hp (RAC) car. The "Ten" had a 1097 cc four-cylinder Q-Type engine made by the Swift Motor Company. Unlike the Nine it was a long-stroke engine, with a bore of only 60 mm and stroke of 97 mm. The Ten had a gearbox combined with the rear axle. The car was advertised at £180 for the chassis, and about 250 were made. In 1925 Ariel discontinued car production to concentrate on motorcycles.