David Keith Duckworth, (August 10, 1933 – December 19, 2005), was an English mechanical engineer. He is most famous for designing the Cosworth DFV (Double Four Valve) engine, an engine that revolutionised the sport of Formula One.
Duckworth was born in Blackburn, Lancashire, and was educated at Giggleswick School. He served his two years of national service with the Royal Air Force, during which time he briefly trained to become a pilot but was grounded for dangerous and incompetent flying and was reclassified as a navigator. Duckworth claimed that allergy to medication he was receiving caused his flying problem - in civilian life he became a keen light aircraft and helicopter pilot. After completing his tour of duty, which he finished as a navigator, Duckworth studied engineering at Imperial College London. After completing his BSc degree in 1955 he began working for Lotus as a gearbox engineer.
After only three years with Lotus, Duckworth, along with fellow Lotus employee Mike Costin, founded Cosworth, a racing engine design and development firm, in 1958. Costin was obliged to remain with Lotus, having recently signed a restrictive contract; for the first few years Duckworth worked essentially alone at Cosworth until Mike could join him. From the start the company was closely associated with the Ford Motor Company and Lotus, and the two companies found early success in the newly formed Formula Junior in the early 1960s. Not only did these successes finance Cosworth's move from Barnet to Northampton, but they inspired Lotus founder Colin Chapman to persuade Ford to finance the production of Duckworth's DFV (double four valve) engine.
Chapman's idea was to reduce weight by using the engine as a stressed part of the chassis, bolted straight on to the front monocoque tub, removing the need for a spaceframe around the engine and making it easier for mechanics to maintain the cars. This arrangement has been standard in F1 ever since.
The DFV made a famous debut in the third race of the 1967 season, in the Dutch Grand Prix at Zandvoort. In the back of the Lotus 49, it proved lightning-quick straight out of the box, with Graham Hill taking pole position and Jim Clark taking the win. Teething problems prevented Clark mounting a serious title challenge but the Lotus-Ford was undoubtedly the class of the field. in 1968 the DFV was made available to all teams, and with its enviable power (about 400 bhp) and relatively low price the DFV quickly began to fill up the grid. This spawned a plethora of small, mainly English-based low-budget teams throughout the 1970s, with the DFV last racing in a Minardi in 1985.
The Cosworth DFV, and other engines based on the same design, became the standard in Formula One and many other types of racing and made Duckworth a very wealthy man. In 1980 he sold his majority stake in Cosworth for tax reasons but retained his position as chairman of the company; relinquishing the job to Mike Costin seven years later for health reasons. He was appointed 'President' of the company on his retirement, and remained interested in engines and engineering until his death.
Keith's son Roger joined his father's company and worked as a development engineer in the Road Engines division being a key part of the team that delivered the YB family of engines for the Ford Sierra and escort RS Cosworth vehicles. Roger left Cosworth in 1998 and founded Integral Powertrain Ltd with three of his Cosworth colleagues.