Charles Benjamin Redrup was a mechanical and aeronautical engineer and inventor. Born in Newport, South Wales, he was apprenticed with the Great Western Railway Company. After completing his apprenticeship, he became Assistant Engineer on a cargo vessel. On his return he decided the sea was not for him and joined the firm of Mr R Stephens of Clevedon, Somerset, maker of the Stephens car.

In 1902 he was employed by the Tyneside Engine Co at Barry Dock. Shortly after this he became a partner in Barry Motor Ltd to sell a Supercharged Rotary engine he developed and which was used in motorcycles.

By 1911 Redrup was working with the Gyroscopic Syndicate, but he left in 1913 to form the Hart Engine Company in partnership with his brother, Alfred Redrup, John Boyle from the Gyroscopic Syndicate and his son Walter, and financier Major Arthur Bray. Redrup designed a rotary engine for aircraft, naming it the Hart engine. It was taken up by Vickers and fitted to a Vickers Gun Bus but, after a serious accident during testing, the company did not take up the option.

Redrup went into partnership with John Boyle again in 1918, this time producing radial engines for motorcycles in Leeds under the company name Boyle and Redrup. The company was dissolved in 1921, and Redrup established a new business, the British Radial Co. He had a patented an axial piston engine with a wobble-plate in 1917. A marine version he developed attracted the attention of Crossley Motors, which commissioned a five-cylinder engine from him, and it was probably this that led to AVRO recruiting Redrup.

The Alpha engine that Redrup designed for A.V. Roe and Co Ltd made its first appearance in 1926 at a race at Woodford Aerodrome. It was fitted to an AVRO Gosport. When AVRO merged with Armstrong Siddeley Motors in 1927 Redrup was once again out of a job. He was hired by the Bristol Tramways and Carriage Co, where he would design the Bristol Axial Engine for use in buses.

During the Second World War Redrup rejoined A.V. Roe as Head of the Experimental Armaments Department and was responsible for designing a hydraulic bomb loading system, which up until then had been done manually.

In the post-war years, Redrup continued to design engines for motorcycles and aircraft. He did most of his development work in a home workshop, using simple tools that he joked were little more than a ‘knife and fork.’