Frank Costin (1920–1995) was an automotive engineer who pioneered monocoque chassis design and was instrumental in adapting aircraft aerodynamic knowledge for automobile use. He was the brother of Mike Costin, co-founder of Cosworth. Frank Costin used his aeronautical knowledge to design and build a chassis from plywood. This led to a lightweight, stiff structure, which he could then clothe with an efficient, aerodynamic body, a huge advantage in low-capacity sports car racing of the immediate postwar period.
He was involved in a number of car projects for various manufacturers including Lister and Lotus, where he contributed to the early aerodynamic designs; Marcos, which he co-founded with Jem Marsh (MARsh and COStin); and racecar chassis for Maserati, Lotus, and DTV. He also designed the Costin Amigo, as well as the TMC Costin which was built in Wexford, Ireland in the mid-1980s.
He went on to work on the Costin Sports Roadster in the early 1990s