The Royal Aircraft Factory 1a engine was a British aircraft engine developed during World War I. It was a water-cooled, inline engine that produced around 100 horsepower. Designed for use in various military aircraft, it played a crucial role in enhancing the performance and reliability of early warplanes. This engine was notable for its relatively lightweight design, which allowed for better maneuverability in the air. The Royal Aircraft Factory was known for its innovative contributions to aviation technology, and the 1a engine exemplified their commitment to improving aircraft capabilities during a pivotal time in aviation history.