14 Dec 06
Sikorsky Biplane
John Marston's Sunbeam company began life in 1859 as a bicycle-maker, and by 1899 Marston ventured into the new world of cars; a series of prototypes were drawn up before the first single-cylinder, 18mph cyclecar, designed by Maxwell Maberly-Smith, went on sale in 1901. Looking to make a heavier duty, faster machine, Sunbeam began licensed production of French Berliet cars in 1903, rebodied and badged Sunbeam 12/16; six-cylinder versions and uprated 12/14s followed before the Sunbeam Motorcar Company Ltd was spun off from John Marston Ltd in 1905 and Louis Coatalen, an engineer who had worked at Panhard, De Dion Bouton, Clement, Humber and Hillman, was recruited in 1909 to make the company's first self-developed motor vehicle.
At the Wolverhampton factory, Coatalen produced the 12/16 and a series of racing cars, which featured innovations such as shock absorbers; inspired by Peugeot's cars, his racers started to win events such as the 1914 Tourist Trophy. He wasn't just a car man, though; he designed Sunbeam's first aero engine, the 135bhp Crusader V8 (1912), a sidevalve, watercooled unit. This was tested in a Farman biplane, and was production-ready in time for World War I; according to Sunbeam Aero Engines, by Alec Brew, it was fitted in planes including the Avro 510 seaplane, Sopwith 806 Gunbus, Short 827 seaplane, Curtis R-2 biplane, the Coastal airship and Sikorsky I1'ya Mouromet biplane, as well as numerous other one-offs and low-volume craft from other manufacturers. An earlier 110bhp version was also used in Sunbeam's class-winning 24hp hillclimb car of 1913, as well as in powerboats.
Sunbeam built whole aircraft, too, during the war. Its Moorfield Works constructed over 40 Short 827 seaplanes and 20 bombers (the latter fitted with Sunbeam's Gurkha engine), 60 Avro 504 trainers, 50 Short 310 seaplanes, and nearly 500 Avro 504-series biplanes, making the company one of the most productive aircraft-makers of the era. It also prepared its own bomber, the Type 7, a huge biplane with a 42ft wingspan, a Vickers machine gun and Sunbeam's Arab engine; the Sopwith B1 was faster, though, and was commissioned instead. Sunbeam thus built its last plane, of around 650 in total, in 1919.
It's the company's engines, however, which are better remembered in aviation history. Wolverhampton University's archives detail how the Crusader was followed by the larger Mohawk, developing up to 225bhp; this was tested in Coatalen's racing car (known as Toodles, after his wife) and broke eight speed records on land before crashing into eight other cars at Kalamazoo, causing ten fatalities. Incidentally, Alec Brew claims that the remains of this car were bought by Packard, and the Crusader engine studied - thus influencing Packard's own V12s. The Mohawk was used in large numbers of Pemberton-Billing PB-7 flying boats, Wight 840 and Sopwith 860 seaplanes and Breguet biplanes, amongst others. Another version of the V12, the 1915 Zulu (160bhp) went into Short 827 seaplanes and Coastal airships, and the 240bhp Gurkha into the Short 184.
The Crusader-based engines were increasingly underpowered compared to the new engines from Rolls-Royce; a problem compounded by the tendency of the valves to overheat and some starting problems. So Coatalen looked to his racing car engines and the overhead camshaft design: the result was the 310/320bhp Cossack V12, again used in the Short 310 seaplanes and Handley-Page 0/400 bombers; post-war, it was fitted in Short's airships, the R36, R37 and R38, a project cancelled after a fatal accident over the river Humber.
A smaller 155bhp engine, the Nubian, was also produced in 1916 for the AD flying boat; this is said to have been derived from the 1913 Peugeot racing car's V8 Coatalen had studied. Sunbeam could not produce this engine in time, however, and the AD craft used a Hispano-Suiza engine instead, or Sunbeam's own Arab V8. This 200bhp engine (1916) was lighter and more powerful, though unreliable at first; over 1,000 were made, with manufacture by Austin, Lanchester, Napier and, in the US, Willys Overland, but it was not much-acclaimed. Its most common applications were in the Norman-Thompson flying boats, the Sopwith Cuckoo bomber and the Bristol F.2B biplane.
The Afridi and Maori overhead-cam V12s were rather better; replacing the Crusader and Zulu sidevalve engines, the 200bhp Afridi was succeeded by the 250/260/275bhp Maori (1916). Though unreliable at first, a new dual-ignition system with two spark plugs per cylinder (like Alfa Romeo's Twin Spark technology) solved the issue. The Afridi was used in planes such as the Curtiss R2 biplane, and the Maori in the Fairey Campania seaplane, Fairey III seaplanes and bombers, the Wight and Short 184-series seaplanes, the Handley-Page 0/400 and the HM R33/R34 airships. The Sunbeam-powered R34, with five Maori engines, made the first return air crossing of the Atlantic in 1919.
