Costin's great understanding of airflow management came from his training with the De Havilland Aircraft Company. Working there on high-speed flight, he was unimpressed with the technology of early Fifties motorsport. His brother Mike (who became the "Cos" of Cosworth Engineering, in partnership with Keith Duckworth) had been introduced to the genius of the Lotus chief Colin Chapman, and had himself left De Havilland to work in motorsport. When Chapman began to design a new sportscar for the 1954 season, he was initially disappointed with the supposedly low-drag body another engineer had created for it. Mike Costin called his elder brother to see if he would be interested in assisting.
Frank Costin did not believe a man was a true engineer unless he designed things and then built them from scratch; but he was intrigued by Chapman, and the word "aerodynamic" hooked him. The result was the Lotus Mark Eight, which set new standards for performance and stability in the field, and set Costin on the motorsport road.
Later, when Vandervell became really serious about challenging the might of Ferrari and Maserati in the grand prix arena, he commissioned Chapman to design a new chassis for the 1956 season. Chapman, in turn, suggested that Costin create its bulbous yet dramatic shape which came to epitomise the grand prix car for every schoolboy of the era. In the hands of stars such as Stirling Moss and Tony Brooks, and the rising newcomer Stuart Lewis-Evans, the Vanwalls achieved Vandervell's well- documented desire to "beat the bloody red cars", and though Mike Hawthorn won Britain's first driving championship in 1958 in a Ferrari, Moss, Brooks and Lewis-Evans helped Vanwall to win the newly inaugurated Constructors' World Championship. Thereby was Britain set firmly on the road to the supremacy it now enjoys in grand prix motor racing.
Not all of Costin's projects succeeded; when in 1957 Maserati badly misinterpreted his brutal but elegant coup body design for their Le Mans car, its dismal performance was as nothing to Costin's rage. Despite such episodes, he never lost his enthusiasm for aerodynamic research, which had its expression in a wide variety of vehicles. There were Jaguar- powered racing sportscars, the wooden Protos Formula Two car, the radical 1971 March 711 grand prix car, or his own road-going sports two-seater, the Costin Amigo. With Jem Marsh he founded the Marcos sportscar.
In his later years he continued work as a consultant, recently modifying the body of a Formula Ford single-seater racing car for enhanced performance, and creating his own ultra-light Dragonfly glider in conjunction with his old friend Duckworth. His early days of Olympic- standard swimming had given way to gentler pursuits, including composing music.
Frank Costin was not a man to suffer half-baked projects gladly, and he was never afraid to speak his mind if he disagreed with something. He was a dedicated nonconformist, and more often than not he failed to receive the credit and recognition that were his due. Those who knew him well always spoke fondly of the kind, warm- hearted man sometimes hidden within the hard outer shell with which he protected himself from the many disappointments he suffered in the ethics of his motor-racing colleagues.
Francis Albert Costin, car designer: born 8 June 1920, died 5 February 1995.