Bentley BR1 aero engine
The Humber company in Coventry began making cycles and then moved on to making motor cars. By 1910 Humber was also making aircraft engines including this one, the Bentley BR1 aero engine.
During World War 1 several other Coventry motor car companies made aircraft and aero engines, including Daimler, Standard and Siddeley Deasy. The Bentley engine was one of the most successful aero engines of World War 1. It was designed by W.O. Bentley, who went on to design Bentley cars.