Initially asked in 1914 to study an overheating problem in rotary engines, Captain W. O. Bentley, an established car designer, developed a new and more efficient engine, with a weight-saving effect realized by careful design and the use of aluminum wherever possible. Equally important was the lower cost, as compared to the French Clerget, then widely used in British aircraft; and itself considered an improvement over the earlier Gnome

The initials A. R. 1 stood for Admiral Rotary 1, and was later renamed Model B. R. 1 for Bentley Rotary 1. The Humber Company of Coventry, England was the first to build the B. R. 1, and a larger model, known as the B. R. 2, was also manufactured by other firms. The A. R. 1 was used on aircraft such as the Sopwith F.1 Camel, Sopwith 7 F.1 Snipe, and Avro 504K.

 Display Status

This object is not on display at the National Air and Space Museum. It is either on loan or in storage.
Object Details
Date 1917 Country of Origin United Kingdom Type PROPULSION-Reciprocating & Rotary Manufacturer Humber Ltd. (Coventry, England)
 Designer W. O. Bentley
 Physical Description Type: Rotary, 9 cylinders, air-cooled Power rating: 112 kW (150 hp) at 1,250 rpm Displacement: 17.3 L (1053 cu in.) Bore and Stroke: 120 mm (4.72 in.) x 170 mm (6.69 in.) Weight: 184 kg (405 lb) Dimensions Diameter 107 cm (42 in.), Length 111 cm (43.5 in.)
 Inventory Number A19270007000 Credit Line Transferred from the U.S. Navy Department, Washington, D.C. Data Source National Air and Space Museum Restrictions & Rights Usage conditions apply
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