The final design of a long-line of air-cooled inline engines, the Ranger 440 was used in the Fairchild PT-19 and PT-26 trainers. Evolving from the 1928 6-370 design by Fairchild, the first 440s were introduced in 1941. The name refers to the 440 cubic inch displacement. During the 1930s, Fairchild changed the name of its engine division to Ranger. The Ranger 440 was unique thanks to key research on airflow around inline engines. A very reliable engine, it was considered "dirty" since the design elements that allowed the exact amount of airflow across the cylinders for cooling didn't carry away grime. Over 6,600 of the 440 series were made, with the I-440-1 producing 170 horsepower with the I-440-3 and the I-440-7 each yielding 200 horsepower.