LeRhone C-9 Note: This item is currently in storage. The LeRhone C-9 was a French air-cooled rotary engine rated at 80 hp. It was installed in combat airplanes early in World War I, but as larger and more powerful engines were developed, it was gradually relegated to training-type airplanes. LeRhone engines were being manufactured in England, Italy and the United States in addition to France. In fact, the German-produced 110-hp Oberursel was practically an exact copy of the 110-hp LeRhone. Click here to return to the Featured Accessions index. Find Out More Related Fact Sheets Oberursel UR-2 Rotary Engine Note: The appearance of hyperlinks does not constitute endorsement by the National Museum of the USAF, the U.S. Air Force, or the Department of Defense, of the external website, or the information, products or services contained therein.