Alessandro Anzani began building motorcycle engines in France around 1905. Unusually, his motors were air- rather than water-cooled, making them light. His first designs were two-cylinder V-engines, and he rode machines powered by them to records and race success in 1905 and 1906. In the same period he had developed a three-cylinder version, more powerful than the twins.
In response to the growing interest in aviation in France after the Wright brothers’ visit in 1908, Anzani produced the first of a series of three-cylinder fan flight engines. The cylinders were each a single iron casting and the one-piece crankcase was aluminium. In most of these the outer cylinders were at 60° to the central one, they were all air-cooled side-valve engines; each exhaust valve was controlled from below by a cam in the crankcase. Each was mounted in a cell to the side of the cylinder, with the automatic, atmospheric pressure -driven spring-loaded inlet valve immediately above it, partly to minimise volume and partly to help cool the hot exhaust valve.
It was an engine of this sort that famously powered Louis Blériot’s Type XI monoplane across La Manche (the English Channel) on 25 July 1909.