• Bentley, Walter Owen

Walter Owen Bentley was born on 16 September 1888, in Hampstead, London, the son of Alfred Bentley, a retired businessman, and his wife Emily (née Waterhouse). He was privately educated at Clifton College, Bristol, from 1902 until 1905 when he left to begin a five-year apprenticeship with the Great Northern Railway in Doncaster. After his apprenticeship he studied theoretical engineering at King's College London and then took employment with the National Motor Cab Co, where his duties included overseeing maintenance of the fleet's 250 Unic taxis. In 1912 he joined his brother, Horace Millner Bentley, in a firm called Bentley & Bentley that sold French Doriot, Flandrin & Parant (DFP) cars. Dissatisfied with the performance of the DFPs Walter Bentley – who preferred to be known as W O – was inspired by a paperweight to have pistons made for the engine in aluminium alloy. Fitted with the alloy pistons and a modified camshaft, a DFP took several records at Brooklands in 1913 and 1914. At the outbreak of the First World War Bentley knew that using aluminium alloy pistons in military applications would benefit the national interest and approached Commander Wilfred Briggs, the official liaison between manufacturers and the Navy. Commissioned in the Royal Naval Volunteer Reserve, Bentley was asked to share his engine design ideas with Louis Coatalen at Sunbeam Motor Car Co Ltd and Ernest Hives at Rolls-Royce Ltd, resulting in his innovation being used in all of their aero engines.

Bentley subsequently liaised with Gwynne’s Engineering Co, Chiswick, which made French-designed Clerget engines under licence, with a brief to improve their quality and reliability. However, due to production pressures Gwynnes could not allow Bentley sufficient development time so the Navy sent him to Humber Ltd’s factory in Coventry where he refined the research carried out at Gwynnes to create the Admiralty Rotary 1 (AR1). This was later re-named the Bentley Rotary 1 (BR1) once production began at Humber Ltd and Vickers Ltd. During his time at Humber Bentley liaised with squadrons in France to determine how his engines were working in the field. He went on to design the bigger Bentley Rotary 2 (BR2) which went into production in late 1917. As a result of manufacturing problems with the BR1, Daimler Co Ltd was made the manufacturing hub for the BR2 coordinating the manufacturing efforts of Daimler, Crossley, Gwynnes, Humbers and Ruston Proctor. While liaising with Daimlers, Bentley developed the Daimler sleeve valve engine used to power tanks. In recognition of his wartime design work Bentley was awarded the MBE.

Upon demobilisation Bentley was given a £1,000 gratuity which, along with an award of £8,000 in recognition of the use of his aluminium pistons and his creation of reliable aero engines, gave him the resources to form car manufacturers Bentley Motors in Cricklewood, London, in 1919, with Frank Burgess and Harry Varley. Bentley Motors’ cars won the 24-hour Le Mans race several times during the 1920s, but the company soon got into financial difficulties and was bought out by Rolls-Royce Ltd in 1931, for whom Bentley continued to work until 1935 when he to join Lagonda Ltd, Staines, as technical director. There he worked on designing new engines and, during the Second World War, on armament production. However, that company had also got into financial trouble by 1947 when it was bought by David Brown & Sons (Huddersfield) Ltd, largely to acquire the engines and engineering skills of Bentley for the firm’s new line of Aston Martin motor cars. Bentley moved on from Aston Martin-Lagonda to Armstrong Siddeley Motors Ltd in 1947, where he designed another engine before retiring in 1950. Bentley married three times, but had no children - Leonie Gore in 1914 (died 1919), Poppy Hutchinson in 1920 (divorced 1931) and Margaret Roberts Hutton, née Murray, in 1934. He died on 13 August 1971 in Woking, Surrey.