| Sunbeam 3-litre | |
|---|---|
 1926 Sunbeam 3-litre Super Sports 2-door | |
| Overview | |
| Manufacturer | Sunbeam |
| Production | 1926–1930 [1] |
| Body and chassis | |
| Body style | lightweight open tourer |
| Powertrain | |
| Engine | 2920 cc Straight-6 dohc [2] |
| Transmission | 4-speed manual sliding-pinion [2] |
| Dimensions | |
| Wheelbase | 130.5 in (3,315 mm) [2] |
The Sunbeam 3-litre is a heavy 26 long cwt (2,912 lb; 1,321 kg) [1] sports car introduced by Sunbeam in October 1925 [3] at the London Motor Show, [2] and was offered from 1926 until 1930. It was seen at the time and subsequently as the retort of Louis Hervé Coatalen, Sunbeam's energetic chief engineer, to the Bentley 3 Litre which by then was beginning to make its mark, having won at Le Mans earlier that year. [2]
Sunbeam Motor Car Company Limited was a British motor car manufacturer with its works at Moorfields in Blakenhall, a suburb of Wolverhampton in the county of Staffordshire, now West Midlands. Its Sunbeam name had been registered by John Marston in 1888 for his bicycle manufacturing business. Sunbeam motor car manufacture began in 1901. The motor business was sold to a newly incorporated Sunbeam Motor Car Company Limited in 1905 to separate it from Marston's pedal bicycle business; Sunbeam motorcycles were not made until 1912.
Louis Hervé Coatalen was an automobile engineer and racing driver born in Brittany who spent much of his adult life in Britain and took British nationality. He was a pioneer of the design and development of internal combustion engines for cars and aircraft.
The Bentley 3 Litre was a car chassis manufactured by Bentley. The company's first it was developed from 1919 and made available to customers' coachbuilders from 1921 to 1929. The Bentley was very much larger than the 1368 cc Bugattis that dominated racing at the time, but double the size of engine and strength compensated for the extra weight. The 4000 lb (1800 kg) car won the 24 Hours of Le Mans in 1924, with drivers John Duff and Frank Clement, and again in 1927, this time in Super Sports form, with drivers S. C. H. "Sammy" Davis and Dudley Benjafield. Its weight, size, and speed prompted Ettore Bugatti to call it "the fastest lorry in the world."
The Sunbeam's engine was of 2,920 cc, distributed between six cylinders. [2] It featured inclined valves operated via easily adjustable tappet levers by two overhead camshafts, an important innovation at the time. [2] The detailed design of the engine followed many of the principles of the engines which were gathering plaudits for the company on European racing circuits. [2] The cylinder head and block were formed from a single casting which was then considered normal for high-performance engines. [2] One of the novel features of the engine was its use of dry-sump lubrication whereby engine oil was drawn from a tank positioned beside the engine. [2] In 1929 a supercharger was added, increasing the power output to 135bhp. [4]
The cylinder bores translated into a fiscal horse-power rating of 20.9 hp which under the system operating in the 1920s attracted an annual Road Fund Tax of £21. [2] The big four-cylinder engines of the competitor vehicles from Bentley incurred an annual Road Fund Tax of £16. [2] The difference of £5 might be considered immaterial for anyone who could afford to purchase and run a car of this type, but £5 was at the time more than the average weekly wage in Britain, [2] [ citation needed ] so the annual saving to the Bentley buyer may well have been significant even in this class.
The tax horsepower or taxable horsepower was an early system by which taxation rates for automobiles were reckoned in some European countries, such as Britain, Belgium, Germany, France, and Italy; some US states like Illinois charged license plate purchase and renewal fees for passenger automobiles based on taxable horsepower. The tax horsepower rating was computed not from actual engine power but by a simple mathematical formula based on cylinder dimensions. At the beginning of the twentieth century, tax power was reasonably close to real power; as the internal combustion engine developed, real power became larger than nominal taxable power by a factor of ten or more.
The Bentley gained a reputation as the more robust of the two cars, although in standard form the Sunbeam was reported to be marginally quicker. Two Sunbeams were entered in the 1925 Le Mans, [5] one driven by Henry Segrave and George Duller, the other by Jean Chassagne and Sammy Davis. Segrave and Duller were forced to retire but Chassagne and Davis achieved second place, beaten only by the Lorraine-Dietrich of Rossignol and de Courcelles. [2] In retrospect the Sunbeam's achievement became eclipsed by the extent to which the race came to be dominated by Bentleys during the second half of the decade.
The 1925 24 Hours of Le Mans was the 3rd Grand Prix of Endurance, and took place on 20 and 21 June 1925. It was the last of the three races spanning 1923 to 1925 to determine the winner of the Rudge-Whitworth Triennial Cup, as well the second race of the inaugural Biennial Cup.
Sir Henry O'Neal de Hane Segrave was an early British pioneer in land speed and water speed records. Segrave, who set three land and one water record, was the first person to hold both titles simultaneously and the first person to travel at over 200 miles per hour (320 km/h) in a land vehicle. He died in an accident in 1930 shortly after setting a new world water speed record on Windermere in the Lake District, England. The Segrave Trophy was established to commemorate his life.
Jean Chassagne was a pioneer submariner, aviator and French racecar driver active 1906-1930. Chassagne finished third in the 1913 French Grand Prix; won the 1922 Tourist Trophy and finished second in the 1925 Le Mans Grand Prix d'Endurance - all in Sunbeam motorcars. He was second in the 1921 Italian Grand Prix with a Ballot, and set speed records and won races at Brooklands and hill climbs internationally.
Although the sturdily constructed chassis [2] [ citation needed ] was based on that from earlier Sunbeams, the hitherto characteristic semi-elliptical leaf springs were, at the back, replaced by cantilever rear springs which during the second half of the decade became a Sunbeam hallmark. [2]
