With a basic design dating from 1929, the L-440s were designed and built by Ranger Engine Division, part of Fairchild Aircraft, and were used mainly in Fairchild designed planes. Featuring inverted cylinders, a relatively rare configuration for an American engine, over 6,500 L-440s of all types were built during World War II. Ranger extensively researched cooling airflow and designed close-fitting baffles around the cylinders. Requiring a much smaller air intake in the cowling, it was said at the time that an L-440 transformed an ordinary aircraft into a beautiful one. While the Ranger sixes were reliable, their close cowling made them quite dirty.