Today in Motorcycle History

W. O. Bentley, Motorcyclist

Walter Bentley, Brooklands
Walter Bentley (left) with the 1910 IoM TT Indian team after winning 1-2-3 at Brooklands

Sunbeam V12
Sunbeam V12 273 horsepower

W.O. Bentley, youngest son of parents both born in Adelaide, South Australia, was founder of the Bentley car company. Prior to this he was a keen motorcyclist who raced Quadrant, Rex, and Indian motorcycles in the years preceding the First World War, competing in two Isle of Man Tourist Trophy races.

He also sold and raced automobiles which he modified for increased performance by replacing the standard cast iron pistons with aluminium alloy units. His cars flogged the opposition mercilessly and he was not quick to give away the secret of his success.

When the guns of August thundered he revealed his secret*. He spoke to Rolls Royce who responded by fitting alloy pistons to their first aero engine. As is well known, Rolls Royce went on to build the Merlin engines fitted to Spitfires and Hurricanes, the planes which won the Battle of Britain.

He also spoke to Louis Coatalen, chief engineer at Sunbeam. Their aircraft engine plant expanded to cover several acres and produced thousands of aero engines during the war, all with alloy pistons.

Bentley became Mr Fixit for all things aviation, and one thing that desperately required attention was a French rotary engine made under licence in England. He bustled off to Humber, was given a workshop and a team, and designed a new rotary engine far superior to its predecessor which became the powerplant of choice for several other aircraft.

He left the services as a full captain in the RAF with a grant of £8000 (approx £250k today) and an MBE.

W.O. Bentley established his Bentley company in 1919, and the cars he designed and built won Le Mans five times between 1924 and 1930.

W.O. (as he was known) sold the Bentley firm to to Rolls-Royce in 1931. He joined Lagonda around 1935, and also worked with Aston Martin and Armstrong Siddeley.

Notes: Cappa used aluminium pistons in 1906, and the Borgo firm fitted them in 1911.

Sources:, wikiwand, History Website UK,, Museum Victoria

If you have information to add on this topic, please contact us