Renault 90 hp

The Renault 90 hp, also known as the 12A, was the world’s first V12 aircraft engine. Developed in 1911, it evolved from Renault’s earlier V8 models and retained the same air-cooled design.

The 90 hp model was also the first Renault engine to feature articulated master-and-slave connecting rods, allowing a pair of pistons to connect to a single bearing. As with other air-cooled Renault engines of the era, the propeller was mounted on an extension of the camshaft, which rotated at half the engine speed. This configuration enabled both the engine and the propeller to operate at their most efficient rotational speeds without the need for a dedicated reduction gearbox. Despite the incorporation of these design elements, the engine was relatively heavy for its power output.

The Renault 90 hp was first exhibited in December 1911 at the Paris Air Show and powered several aircraft during the 1912 competition season, though without any notable sporting successes. Renault followed up with a similarly designed, 100 hp model in the summer of 1912.