The McCulloch O-100 is a four-cylinder, air cooled four piston drone engine developed by the McCulloch Aircraft Corporation (later to become the McCulloch Motors Corp.) which was founded 1943 in Milwaukee, Wisconsin and later moved to Los Angeles, California.

The aircraft corporation was formed from the McCulloch Engineering Company.

[2] In 1972, the corporation was renamed McCulloch Motors Corp. of Los Angeles and sold to Northrop-Ventura.

The first engines were used for industrial motor pumps and chainsaws.

development, the engines had experimental aircraft applications.