The AeroVee 4.0 is a lightweight, four-cylinder engine designed for use in small aircraft. It is known for its reliability and efficiency, making it a popular choice among aviation enthusiasts and builders of experimental aircraft. The engine typically runs on automotive fuel, which helps reduce operating costs. This engine features a compact design and is often praised for its ease of installation and maintenance. The AeroVee 4.0 is part of a broader trend in the aviation industry towards using more accessible and cost-effective power sources, appealing to hobbyists and those looking to build their own aircraft.