Air Cooled Motors Corporation was formed in 1935 by several former engineers of the failed Franklin Automobile Company. By 1938 a range of flat-4 and 6 aircraft engines was being produced, retaining the Franklin name.

In May 1942, the U.S. Navy issued a contract to Aircooled for 14 XO-805-2 engines. By June 1943, 0-805-2 engines had been installed in a prototype Interstate XTD2R-1, a twin-engine, radio-controlled, bomb carrier (drone aircraft). Initially, Interstate experienced severe overheating difficulties with the engine installation, and two engines burned up during testing. After considerable trouble-shooting, the overheating problem began to clear up. However, because much work had yet to be done and the gain was not considered worthwhile, the Navy canceled the contract.

In 1975, the company disbanded and sold all rights to the Polish government, becoming part of PZL, an association of Polish aero and engine manufacturers. Following the 1989 fall of Communism, the firm became WSK PZL – Rzeszów.