When Citroën Tried Rotary Power – GS Birotor 1973

Citroën promotional film from the early 1970

This is an original Citroën promotional film from the early 1970s, tracing the history of rotary engines and showcasing the debut of the Citroën GS Birotor. The film begins with the invention of the wheel and mankind’s search for new energy sources — from muscle power to animals, steam, and finally the automobile.

It then follows the long quest to create an engine that could deliver smooth rotary motion directly, leading through centuries of inventions before reaching the breakthrough of Felix Wankel’s rotary engine in 1954. With clear narration and historical footage, the video explains how the Wankel rotary engine works: a triangular rotor turning inside a specially shaped housing to complete three combustion cycles per revolution.

Compact, powerful, and quiet, it promised to be the future of automotive design. The story continues with Citroën’s partnership with NSU, the creation of Comotor, and the exhaustive testing of rotary prototypes. All of this culminated in the Citroën GS Birotor — launched in 1973 with a twin-rotor engine producing 107 horsepower, smooth-shifting transmission, and advanced engineering for its time. This rare film captures the excitement of a bold automotive experiment: Citroën’s dream of bringing rotary power to the road.

See it in person at the Tampa Bay Automobile Museum.