The Alfa Romeo D2 was a nine-cylinder radial engine for aircraft use produced in Italy. It was typically rated between 240-270 hp. The engine was designed by Vittorio Jano and produced 600 units between 1931-1934. This engine was also first purpose-built aircraft engine produced by Alfa Romeo, before it all Alfa engines used in airplanes were derived from engines used in cars. A supercharged derivative was produced as the D2 C..